U.S. patent application number 16/255405 was filed with the patent office on 2019-05-23 for reservoir plunger position monitoring and medical device incorporating same.
The applicant listed for this patent is MEDTRONIC MINIMED, INC.. Invention is credited to Afshin BAZARGAN, EJMar FONACIER, Pablo VAZQUEZ, Andrew E. WEAVER.
Application Number | 20190151537 16/255405 |
Document ID | / |
Family ID | 50148660 |
Filed Date | 2019-05-23 |
View All Diagrams
United States Patent
Application |
20190151537 |
Kind Code |
A1 |
BAZARGAN; Afshin ; et
al. |
May 23, 2019 |
RESERVOIR PLUNGER POSITION MONITORING AND MEDICAL DEVICE
INCORPORATING SAME
Abstract
Apparatus are provided for infusion devices and related control
systems and methods. In one embodiment, an infusion device includes
a voided portion adapted to receive a shaft portion that includes a
shaft coupled to a plunger of a reservoir. The shaft portion
includes a detectable feature, and the infusion device includes a
sensing arrangement proximate the voided portion to sense the
detectable feature. In some embodiments, a control module is
coupled to the sensing arrangement to determine a remaining amount
of fluid in the reservoir based at least in part on the sensed
position of the detectable feature. In other embodiments, the
control module identifies an anomalous condition based at least in
part on the sensed position of the detectable feature.
Inventors: |
BAZARGAN; Afshin; (Simi
Valley, CA) ; VAZQUEZ; Pablo; (Granada Hills, CA)
; FONACIER; EJMar; (Woodland Hills, CA) ; WEAVER;
Andrew E.; (Granada Hills, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MEDTRONIC MINIMED, INC. |
Northridge |
CA |
US |
|
|
Family ID: |
50148660 |
Appl. No.: |
16/255405 |
Filed: |
January 23, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15345480 |
Nov 7, 2016 |
10232112 |
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16255405 |
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14323931 |
Jul 3, 2014 |
9517303 |
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15345480 |
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13591129 |
Aug 21, 2012 |
8808269 |
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14323931 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 2205/332 20130101;
A61M 5/1723 20130101; A61M 5/16831 20130101; A61M 2205/3317
20130101; A61M 5/1684 20130101; A61M 5/14248 20130101; A61M
2205/6063 20130101; A61M 2205/6081 20130101; A61M 5/14212 20130101;
A61M 2205/3306 20130101; A61M 2205/3365 20130101; A61M 2205/14
20130101; A61M 2005/16863 20130101; A61M 2205/6054 20130101; A61M
5/1456 20130101 |
International
Class: |
A61M 5/168 20060101
A61M005/168; A61M 5/142 20060101 A61M005/142; A61M 5/145 20060101
A61M005/145 |
Claims
1. A method of operating an infusion device comprising a housing
including a voided portion to receive a shaft portion including a
displaceable shaft coupled to a plunger of a reservoir and a
sensing arrangement proximate the voided portion to sense a
detectable feature on a side of the shaft facing the sensing
arrangement, the method comprising: monitoring an electrical output
signal from the sensing arrangement; and detecting seating of the
reservoir based on the electrical output signal, wherein an
electrical characteristic of the sensing arrangement is influenced
by the detectable feature.
2. The method of claim 1, the detectable feature comprising a
protruding feature, wherein detecting seating of the reservoir
comprises determining the electrical output signal is indicative of
the protruding feature contacting the sensing arrangement.
3. The method of claim 2, wherein a resistance of the sensing
arrangement is influenced by the protruding feature contacting the
sensing arrangement.
4. The method of claim 3, wherein the sensing arrangement comprises
a resistive sensing arrangement having a variable resistance that
is influenced by a position of the protruding feature with respect
to the sensing arrangement.
5. The method of claim 1, the sensing arrangement generating the
electrical output signal based on a proximity of the detectable
feature, wherein detecting seating of the reservoir comprises
determining the electrical output signal is indicative of the
detectable feature within a threshold distance of the sensing
arrangement.
6. The method of claim 5, wherein a capacitance of the sensing
arrangement is influenced by the proximity of the detectable
feature.
7. The method of claim 6, wherein the sensing arrangement comprises
a capacitive sensing arrangement having a variable capacitance that
is influenced by a position of the detectable feature with respect
to the sensing arrangement.
8. The method of claim 5, wherein an inductance of the sensing
arrangement is influenced by the proximity of the detectable
feature.
9. The method of claim 6, wherein the sensing arrangement comprises
an inductive sensing arrangement having a variable inductance that
is influenced by a position of the detectable feature with respect
to the sensing arrangement.
10. The method of claim 1, further comprising automatically
initiating a priming sequence to initialize positioning of the
plunger within the reservoir in response to detecting seating of
the reservoir.
11. The method of claim 1, further comprising, after detecting
seating, providing indication the reservoir has become unseated
when the electrical output signal fails to indicate presence of the
reservoir.
12. The method of claim 1, wherein the sensing arrangement
comprises an optical sensing arrangement.
13. The method of claim 1, further comprising: operating a motor
having a rotor coupled to the shaft to displace the shaft in
response to rotation of the rotor, displacement of the shaft
resulting in displacement of the plunger to deliver fluid from the
reservoir; obtaining a measured shaft position based at least in
part on the electrical output signal provided by the sensing
arrangement, wherein the electrical output signal corresponds to a
position of the detectable feature; determining a remaining amount
of fluid in the reservoir based on the measured shaft position; and
providing a low fluid notification when the remaining amount is
less than a threshold value.
14. The method of claim 1, further comprising: operating a motor
having a rotor coupled to the shaft to displace the shaft in
response to rotation of the rotor, displacement of the shaft
resulting in displacement of the plunger to deliver fluid from the
reservoir; obtaining a measured shaft position based at least in
part on the electrical output signal provided by the sensing
arrangement, wherein the electrical output signal corresponds to a
position of the detectable feature; determining an expected shaft
position based on an amount of rotation of the rotor; and
identifying an occlusion condition when a difference between the
expected shaft position and the measured shaft position exceeds a
threshold amount.
15. The method of claim 1, further comprising: operating a motor
having a rotor coupled to the shaft to displace the shaft in
response to rotation of the rotor, displacement of the shaft
resulting in displacement of the plunger to deliver fluid from the
reservoir; obtaining a measured shaft position based at least in
part on the electrical output signal provided by the sensing
arrangement, wherein the electrical output signal corresponds to a
position of the detectable feature; determining an expected shaft
position based on an amount of rotation of the rotor; and
identifying a drive system anomaly when a difference between the
expected shaft position and the measured shaft position exceeds a
threshold amount.
16. A computer-readable medium having computer-executable
instructions stored thereon that, when executed by a control module
coupled to the sensing arrangement, cause the control module to
perform the method of claim 1.
17. A method of operating an infusion device, the method
comprising: monitoring an electrical output signal from a sensing
arrangement disposed proximate a voided portion of a housing to
sense a protruding feature, the voided portion receiving a shaft
portion including a displaceable shaft coupled to a plunger of a
reservoir and the shaft portion comprising the protruding feature
on a side of the shaft, wherein an electrical characteristic of the
sensing arrangement is influenced by contact with the protruding
feature; and detecting seating of the reservoir based on the
electrical output signal.
18. The method of claim 17, wherein the sensing arrangement
comprises a resistive sensing arrangement having a variable
resistance that is influenced by a position of the protruding
feature with respect to the sensing arrangement.
19. The method of claim 17, further comprising: operating a motor
having a rotor coupled to the shaft to displace the shaft in
response to rotation of the rotor, displacement of the shaft
resulting in displacement of the plunger to deliver fluid from the
reservoir; obtaining a measured shaft position based at least in
part on the electrical output signal provided by the sensing
arrangement, wherein the electrical output signal corresponds to a
position of the protruding feature; determining a remaining amount
of fluid in the reservoir based on the measured shaft position; and
providing a low fluid notification when the remaining amount is
less than a threshold value.
20. The method of claim 17, further comprising: operating a motor
having a rotor coupled to the shaft to displace the shaft in
response to rotation of the rotor, displacement of the shaft
resulting in displacement of the plunger to deliver fluid from the
reservoir; obtaining a measured shaft position based at least in
part on the electrical output signal provided by the sensing
arrangement, wherein the electrical output signal corresponds to a
position of the protruding feature; determining an expected shaft
position based on an amount of rotation of the rotor; and
identifying an occlusion condition when a difference between the
expected shaft position and the measured shaft position exceeds a
threshold amount.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/345,480, filed Nov. 7, 2016, which is a
continuation of U.S. patent application Ser. No. 14/323,931, filed
Jul. 3, 2014, now issued U.S. Pat. No. 9,517,303, which is a
continuation of U.S. patent application Ser. No. 13/591,129, filed
Aug. 21, 2012, now issued U.S. Pat. No. 8,808,269.
TECHNICAL FIELD
[0002] Embodiments of the subject matter described herein relate
generally to medical devices, and more particularly, embodiments of
the subject matter relate to monitoring the position of a plunger
in a fluid infusion device.
BACKGROUND
[0003] Infusion pump devices and systems are relatively well-known
in the medical devices, for use in delivering or dispensing an
agent, such as insulin or another prescribed medication, to a
patient. A typical infusion pump includes a pump drive system which
typically includes a small motor and drive train components that
convert rotational motor motion to a translational displacement of
a plunger (or stopper) in a reservoir that delivers medication from
the reservoir to the body of a user via a fluid path created
between the reservoir and the body of a user. Some fluid infusion
devices also include a force sensor designed to detect and indicate
a pump malfunction and/or non-delivery of the medication to the
patient due to a fluid path occlusion.
[0004] In some fluid infusion devices, the reservoir is obscured
from the user by being contained inside a housing, thereby
preventing the user from being able to visually monitor the amount
of fluid remaining in the reservoir. Additionally, the reservoir
could become disengaged from the drive system due to an unexpected
anomaly within the pump drive system. Thus, it is desirable to
inform the user of the remaining amount of fluid in the reservoir
and notify the user in the event the reservoir becomes disengaged
from the infusion device or there is an anomaly with the drive
system.
BRIEF SUMMARY
[0005] An embodiment of an infusion device is provided. The
infusion device includes a voided portion adapted to receive a
shaft portion that includes a shaft coupled to a plunger of a
reservoir. The shaft portion includes a detectable feature, and the
infusion device includes a sensing arrangement proximate the voided
portion to sense the detectable feature.
[0006] In another embodiment, an infusion device includes a
reservoir having a plunger disposed within a barrel portion, a
shaft that is coupled to the plunger and includes a detectable
feature, and a sensing arrangement proximate the shaft to sense a
position of the detectable feature.
[0007] In yet another embodiment, a method of operating an infusion
device to deliver fluid from a reservoir is provided. The reservoir
includes a plunger coupled to a shaft such that displacement of the
shaft results in displacement of the plunger. The infusion device
includes a sensing arrangement to sense a detectable feature on the
shaft and a motor having a rotor coupled to the shaft to displace
the shaft in response to rotation of the rotor and deliver fluid
from the reservoir. The method involves operating the motor to
displace the shaft and deliver fluid from the reservoir, obtaining
a measured shaft position based at least in part on a position of
the detectable feature sensed by the sensing arrangement,
determining a remaining amount of fluid in the reservoir based on
the measured shaft position, and providing a low fluid notification
when the determined amount of remaining fluid is less than a
threshold value.
[0008] In another embodiment, a method for operating an infusion
device to deliver fluid from a reservoir involves operating a motor
having a rotor coupled to a shaft coupled to a plunger in the
reservoir displace the shaft and deliver fluid from the reservoir,
obtaining a measured shaft position based at least in part on a
position of a detectable feature on the shaft sensed by a sensing
arrangement, determining an expected shaft position based on an
amount of rotation of the rotor, and identifying an anomalous
condition when a difference between the expected shaft position and
the measured shaft position exceeds a threshold amount.
[0009] This summary is provided to introduce a selection of
concepts in a simplified form that are further described below in
the detailed description. This summary is not intended to identify
key features or essential features of the claimed subject matter,
nor is it intended to be used as an aid in determining the scope of
the claimed subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] A more complete understanding of the subject matter may be
derived by referring to the detailed description and claims when
considered in conjunction with the following figures, wherein like
reference numbers refer to similar elements throughout the
figures.
[0011] FIG. 1 depicts an exemplary embodiment of an infusion
system;
[0012] FIG. 2 is a perspective view of an exemplary embodiment of a
fluid infusion device suitable for use in the infusion system of
FIG. 1;
[0013] FIG. 3 is a perspective view that depicts internal structure
of the durable housing of the fluid infusion device shown in FIG.
2;
[0014] FIG. 4 is a perspective view of the drive system in the
durable housing of the fluid infusion device of FIGS. 2-3;
[0015] FIG. 5 is cross-sectional perspective view of the motor of
drive system of FIG. 4 illustrating a sensor integrated
therein;
[0016] FIG. 6 is a perspective view illustrating the drive system
engaged with the shaft of the plunger when the fluid reservoir is
seated within the durable housing of FIG. 3;
[0017] FIG. 7 is a plan view of an exemplary durable housing
including a sensing arrangement that is suitable for use as the
durable housing in the fluid infusion device of FIG. 2 in
accordance with one embodiment;
[0018] FIG. 8 is a plan view of an exemplary fluid reservoir
including a detectable feature that is suitable for use with the
durable housing of FIG. 7 in the fluid infusion device of FIG. 2 in
accordance with one embodiment;
[0019] FIG. 9 is an exploded perspective view of an exemplary
resistive sensing arrangement suitable for use as the sensing
arrangement in the durable housing of FIG. 7 in accordance with one
embodiment;
[0020] FIG. 10 is a cross-sectional view of the resistive sensing
arrangement of FIG. 9;
[0021] FIG. 11 is a block diagram of an exemplary control system
suitable for use with a fluid infusion device;
[0022] FIG. 12 is a flow diagram of an exemplary control process
suitable for use with the control system of FIG. 11;
[0023] FIG. 13 is a plan view of an exemplary durable housing
including a sensing arrangement comprised of a plurality of sensing
elements that is suitable for use as the durable housing in the
fluid infusion device of FIG. 2 in accordance with another
embodiment;
[0024] FIG. 14 is a plan view of an exemplary durable housing
including a magnetic sensing arrangement suitable for use as the
durable housing in the fluid infusion device of FIG. 2 in
accordance with another embodiment;
[0025] FIG. 15 is a plan view of an exemplary reservoir suitable
for use with the durable housing of FIG. 14 in accordance with one
embodiment;
[0026] FIG. 16 is a plan view of another exemplary reservoir
suitable for use with the durable housing of FIG. 14 in accordance
with one embodiment;
[0027] FIG. 17 is a plan view of an exemplary durable housing
including an inductive sensing arrangement suitable for use as the
durable housing in the fluid infusion device of FIG. 2 in
accordance with another embodiment;
[0028] FIG. 18 is a plan view of an exemplary reservoir suitable
for use with the durable housing of FIG. 17 in accordance with one
embodiment;
[0029] FIG. 19 is a plan view of an exemplary durable housing
including an optical sensing arrangement that is suitable for use
as the durable housing in the fluid infusion device of FIG. 2 in
accordance with another embodiment;
[0030] FIG. 20 is a plan view of an exemplary reservoir suitable
for use with the durable housing of FIG. 19 in accordance with one
embodiment;
[0031] FIG. 21 is a plan view of another exemplary durable housing
including an optical sensing arrangement that is suitable for use
as the durable housing in the fluid infusion device of FIG. 2 in
accordance with another embodiment;
[0032] FIG. 22 is a plan view of an exemplary reservoir suitable
for use with the durable housing of FIG. 21 in accordance with one
embodiment; and
[0033] FIG. 23 is a plan view of another exemplary reservoir
suitable for use with the durable housing of FIG. 21 in accordance
with one embodiment.
DETAILED DESCRIPTION
[0034] The following detailed description is merely illustrative in
nature and is not intended to limit the embodiments of the subject
matter or the application and uses of such embodiments. As used
herein, the word "exemplary" means "serving as an example,
instance, or illustration." Any implementation described herein as
exemplary is not necessarily to be construed as preferred or
advantageous over other implementations. Furthermore, there is no
intention to be bound by any expressed or implied theory presented
in the preceding technical field, background, brief summary or the
following
DETAILED DESCRIPTION
[0035] Embodiments of the subject matter described herein generally
relate to infusion devices adapted to sense, measure, or otherwise
detect the position of a shaft coupled to a plunger disposed within
a barrel of a reservoir to estimate the remaining amount of fluid
in the reservoir and identify an anomalous condition based on the
shaft position. As described in greater detail below, in exemplary
embodiments, the housing of the infusion device includes a voided
portion corresponding to the shaft that includes a sensing
arrangement capable of sensing or otherwise detecting one or more
detectable feature(s) associated with the position of the shaft. In
this regard, although the subject matter may be described herein in
the context of the detectable feature(s) being provided on the
shaft, in other embodiments, the detectable feature(s) may be
provided at other locations such that the sensing and/or detection
of the detectable feature(s) by the sensing arrangement is
influenced by or otherwise corresponds to the position of the
shaft. For example, the detectable feature(s) may be provided at a
location that allows the shaft to be interposed between the sensing
arrangement and the detectable feature(s), such that the position
of the shaft influences the ability of the sensing arrangement to
sense or otherwise detect the detectable feature(s) and thereby
provides an indication of the shaft position.
[0036] In exemplary embodiments, based on the measured shaft
position obtained using the sensing arrangement, the remaining
amount of fluid is estimated to provide the user with indication of
the remaining amount of fluid and/or alert the user when the
remaining amount falls below a threshold amount where the user
would like to be notified to replace and/or refill the reservoir.
Additionally, during operation of the infusion device, an expected
shaft position may be determined and compared to the measured shaft
position for detecting or otherwise identifying an anomalous
condition, such as an occlusion condition or a drive system
anomaly, when the difference between the expected shaft position
and the measured shaft position exceeds a threshold amount.
Furthermore, in embodiments where the shaft is integral with or
otherwise joined to the plunger of the reservoir, the presence of
the reservoir in the infusion device may be detected or otherwise
identified based on the measured shaft position. For example, the
infusion device may include a housing adapted to receive the
reservoir as described below, and seating of the reservoir within
the housing may be detected or otherwise identified when the shaft
is detected.
[0037] While the subject matter described herein can be implemented
in any electronic device that includes a displaceable shaft coupled
to a motor, exemplary embodiments described below are implemented
in the form of medical devices, such as portable electronic medical
devices. Although many different applications are possible, the
following description focuses on a fluid infusion device (or
infusion pump) as part of an infusion system deployment. For the
sake of brevity, conventional techniques related to infusion system
operation, insulin pump and/or infusion set operation, and other
functional aspects of the systems (and the individual operating
components of the systems) may not be described in detail here.
Examples of infusion pumps may be of the type described in, but not
limited to, U.S. Pat. Nos.: 4,562,751; 4,685,903; 5,080,653;
5,505,709; 5,097,122; 6,485,465; 6,554,798; 6,558,320; 6,558,351;
6,641,533; 6,659,980; 6,752,787; 6,817,990; 6,932,584; and
7,621,893 which are herein incorporated by reference.
[0038] Turning now to FIG. 1, in exemplary embodiments, an infusion
system 100 includes, without limitation, a fluid infusion device
(or infusion pump) 102, a sensing arrangement 104, a command
control device (CCD) 106, and a computer 108. The components of an
infusion system may be realized using different platforms, designs,
and configurations, and the embodiment shown in FIG. 1 is not
exhaustive or limiting. In practice, the infusion device 102 and
the sensing arrangement 104 are secured at desired locations on the
body of a user (or patient), as illustrated in FIG. 1. In this
regard, the locations at which the infusion device 102 and the
sensing arrangement 104 are secured to the body of the user in FIG.
1 are provided only as a representative, non-limiting, example. The
elements of the infusion system 100 may be similar to those
described in U.S. patent application Ser. No. 13/049,803, assigned
to the assignee of the present application, the subject matter of
which is hereby incorporated by reference in its entirety.
[0039] In the illustrated embodiment of FIG. 1, the infusion device
102 is designed as a portable medical device suitable for infusing
a fluid, a liquid, a gel, or other agent into the body of a user.
In exemplary embodiments, the infused fluid is insulin, although
many other fluids may be administered through infusion such as, but
not limited to, HIV drugs, drugs to treat pulmonary hypertension,
iron chelation drugs, pain medications, anti-cancer treatments,
medications, vitamins, hormones, or the like. In some embodiments,
the fluid may include a nutritional supplement, a dye, a tracing
medium, a saline medium, a hydration medium, or the like. The
sensing arrangement 104 generally represents the components of the
infusion system 100 configured to sense a condition of the user,
and may include a sensor, a monitor, or the like, for providing
data indicative of the condition that is sensed and/or monitored by
the sensing arrangement. In this regard, the sensing arrangement
104 may include electronics and enzymes reactive to a biological
condition, such as a blood glucose level, or the like, of the user,
and provide data indicative of the blood glucose level to the
infusion device 102, the CCD 106 and/or the computer 108. For
example, the infusion device 102, the CCD 106 and/or the computer
108 may include a display for presenting information or data to the
user based on the sensor data received from the sensing arrangement
104, such as, for example, a current glucose level of the user, a
graph or chart of the user's glucose level versus time, device
status indicators, alert messages, or the like. In other
embodiments, the infusion device 102, the CCD 106 and/or the
computer 108 may include electronics and software that are
configured to analyze sensor data and operate the infusion device
102 to deliver fluid to the body of the user based on the sensor
data and/or preprogrammed delivery routines. Thus, in exemplary
embodiments, one or more of the infusion device 102, the sensing
arrangement 104, the CCD 106, and/or the computer 108 includes a
transmitter, a receiver, and/or other transceiver electronics that
allow for communication with other components of the infusion
system 100, so that the sensing arrangement 104 may transmit sensor
data or monitor data to one or more of the infusion device 102, the
CCD 106 and/or the computer 108. In various embodiments, the
sensing arrangement 104 may be secured to the body of the user or
embedded in the body of the user at a location that is remote from
the location at which the infusion device 102 is secured to the
body of the user. In various other embodiments, the sensing
arrangement 104 may be incorporated within the infusion device 102.
In other embodiments, the sensing arrangement 104 may be separate
and apart from the infusion device 102, and may be, for example,
part of the CCD 106. In such embodiments, the sensing arrangement
104 may be configured to receive a biological sample, analyte, or
the like, to measure a condition of the user.
[0040] As described above, in various embodiments, the CCD 106
and/or the computer 108 include electronics and other components
configured to perform processing, delivery routine storage, and to
control the infusion device 102 in a manner that is influenced by
sensor data measured by and/or received from the sensing
arrangement 104. By including control functions in the CCD 106
and/or the computer 108, the infusion device 102 may be made with
more simplified electronics. However, in other embodiments, the
infusion device 102 may include all control functions, and may
operate without the CCD 106 and/or the computer 108. In various
embodiments, the CCD 106 may be a portable electronic device. In
addition, in various embodiments, the infusion device 102 and/or
the sensing arrangement 104 may be configured to transmit data to
the CCD 106 and/or the computer 108 for display or processing of
the data by the CCD 106 and/or the computer 108.
[0041] In some embodiments, the CCD 106 and/or the computer 108 may
provide information to the user that facilitates the user's
subsequent use of the infusion device 102. For example, the CCD 106
may provide information to the user to allow the user to determine
the rate or dose of medication to be administered into the user's
body. In other embodiments, the CCD 106 may provide information to
the infusion device 102 to autonomously control the rate or dose of
medication administered into the body of the user. In some
embodiments, the sensing arrangement 104 may be integrated into the
CCD 106. Such embodiments may allow the user to monitor a condition
by providing, for example, a sample of his or her blood to the
sensing arrangement 104 to assess his or her condition. In some
embodiments, the sensing arrangement 104 and the CCD 106 may be for
determining glucose levels in the blood and/or body fluids of the
user without the use of, or necessity of, a wire or cable
connection between the infusion device 102 and the sensing
arrangement 104 and/or the CCD 106.
[0042] In some embodiments, the sensing arrangement 104 and/or the
infusion device 102 may utilize a closed-loop system for delivering
fluid to the user. Examples of sensing devices and/or infusion
pumps utilizing closed-loop systems may be found at, but are not
limited to, the following U.S. Pat. Nos.: 6,088,608, 6,119,028,
6,589,229, 6,740,072, 6,827,702, and 7,323,142, all of which are
incorporated herein by reference in their entirety. In such
embodiments, the sensing arrangement 104 is configured to sense a
condition of the user, such as, blood glucose level or the like.
The infusion device 102 may be configured to deliver fluid in
response to the condition sensed by the sensing arrangement 104. In
turn, the sensing arrangement 104 may continue to sense a new
condition of the user, allowing the infusion device 102 to deliver
fluid continuously in response to the new condition sensed by the
sensing arrangement 104 indefinitely. In some embodiments, the
sensing arrangement 104 and/or the infusion device 102 may be
configured to utilize the closed-loop system only for a portion of
the day, for example only when the user is asleep or awake.
[0043] FIGS. 2-6 depict an exemplary embodiment of a fluid infusion
device 200 suitable for use as the infusion device 102 in the
infusion system 100 of FIG. 1. FIGS. 2-3 depict perspective views
of the fluid infusion device 200, which includes a durable housing
202 and a base plate 204. While FIG. 2 depicts the durable housing
202 and the base plate 204 as being coupled together, in practice,
the durable housing 202 and/or the base plate 204 may include
features, structures, or elements to facilitate removable coupling
(e.g., pawls, latches, rails, slots, keyways, buttons, or the like)
and accommodate a removable/replaceable fluid reservoir 206. As
illustrated in FIG. 3, in exemplary embodiments, the fluid
reservoir 206 mates with, and is received by, the durable housing
202. In alternate embodiments, the fluid reservoir 206 mates with,
and is received by, the base plate 204.
[0044] In exemplary embodiments, the base plate 204 is temporarily
adhered to the skin of the user, as illustrated in FIG. 1 using,
for example, an adhesive layer of material. After the base plate
204 is affixed to the skin of the user, a suitably configured
insertion device or apparatus may be used to insert a fluid
delivery needle or cannula 208 into the body of the user. The
cannula 208 functions as one part of the fluid delivery path
associated with the fluid infusion device 200. The durable housing
202 receives the fluid reservoir 206 and retains the fluid
reservoir 206 in a substantially fixed position and orientation
with respect to the durable housing 202 and the base place 204
while the durable housing 202 and the base plate 204 are coupled.
The durable housing 202 is configured to secure to the base plate
204 in a specified orientation to engage the fluid reservoir 206
with a reservoir port receptacle formed in the durable housing 202.
In particular embodiments, the fluid infusion device 200 includes
certain features to orient, align, and position the durable housing
202 relative to the base plate 204 such that when the two
components are coupled together, the fluid reservoir 206 is urged
into the reservoir port receptacle to engage a sealing assembly and
establish a fluid seal, as described in more detail below.
[0045] In exemplary embodiments, the fluid reservoir 206 includes a
fluid delivery port 210 that cooperates with the reservoir port
receptacle to establish a fluid delivery path. In this regard, the
fluid delivery port 210 has an interior 211 defined therein that is
shaped, sized, and otherwise configured to receive a sealing
element when the fluid reservoir 206 is engaged with the reservoir
port receptacle on base plate 204. The sealing element forms part
of a sealing assembly for the fluid infusion device 200 and
preferably includes one or more sealing elements and/or fluid
delivery needles configured to establish fluid communication from
the interior of the reservoir 206 to the cannula 208 via the fluid
delivery port 210 and a mounting cap 212, and thereby establish a
fluid delivery path from the reservoir 206 to the user via the
cannula 208. In the illustrated embodiment, the fluid reservoir 206
includes a second fluid port for receiving fluid. For example, the
second fluid port 213 may include a pierceable septum, a vented
opening, or the like to accommodate filling (or refilling) of the
fluid reservoir 206 by the patient, a doctor, a caregiver, or the
like.
[0046] As illustrated in FIG. 3, the reservoir 206 includes a
barrel 220 for containing fluid and a plunger 222 (or stopper)
positioned to push fluid from inside the barrel 220 of the
reservoir 206 along the fluid path through the cannula 208 to the
user. A shaft 224 is mechanically coupled to or otherwise engages
the plunger 222, and the shaft 224 has exposed teeth 225 that are
configured to mechanically couple or otherwise engage the shaft 224
with a drive system 230 contained in the durable housing 202. In
this regard, the shaft 224 functions as a rack gear as part of a
rack and pinion gear configuration, as described in greater detail
below. Although the subject matter may be described herein in the
context of the shaft 224 being integral with or otherwise part of
the plunger 222, in practice, the shaft 224 and the plunger 222 may
be provided separately.
[0047] FIGS. 4-6 depict perspective and cross-sectional views of
the drive system 230 provided in the durable housing 202. Various
aspects of the motor drive system 230 may be similar to those
described in U.S. patent application Ser. No. 13/049,803. The drive
system 230 includes a motor 232 having a rotor 530 that is
mechanically coupled to a gear assembly 236 that translates
rotation of the rotor 530 of the motor 232 to translational
displacement the plunger 222 in the direction 250 of the fluid
delivery port 210. In exemplary embodiments, the motor 232 is
realized as a DC motor, such as a stepper motor or brushless DC
motor capable of precisely controlling the amount of displacement
of the plunger 222 during operation of the infusion device 200, as
described in greater detail below. As best illustrated in FIGS.
4-5, in exemplary embodiments, the rotor 530 of the motor 232 is
mechanically coupled to a rotary shaft 402, which, in turn, is
mechanically coupled to a first gear 404 of the gear assembly 236.
In the illustrated embodiment of FIGS. 4-5, the first gear 404 is
coaxial and/or concentric to and disposed about the rotary shaft
402, and the first gear 404 is affixed to or otherwise integrated
with the rotary shaft 402 such that the first gear 404 and the
rotary shaft 402 rotate in unison. The gear assembly 236 also
includes a second gear 238 (or pinion gear) having exposed teeth
239 that are configured to mate with or otherwise engage the
exposed teeth 225 on the shaft 224, such that rotation or
displacement of the pinion gear 238 produces a corresponding linear
displacement of the shaft 224 in direction 250, which results in a
corresponding displacement of the plunger 222 in direction 250 to
deliver fluid from the user. The gear assembly 236 includes various
additional gears and potentially other drive train components
(e.g., screws, cams, ratchets, jacks, pulleys, pawls, clamps, nuts,
slides, bearings, levers, beams, stoppers, plungers, sliders,
brackets, guides, bearings, supports, bellows, caps, diaphragms,
bags, heaters, and the like) configured to mechanically couple the
first gear 404 to the pinion gear 238 so that rotation (or
displacement) of the first gear 404 produces a corresponding
rotation (or displacement) of the pinion gear 238.
[0048] During operation of the fluid infusion device 200, when the
motor 232 is operated to rotate the rotor 530, the rotary shaft 402
rotates in unison with the rotor 530 to cause a corresponding
rotation of the first gear 404, which, in turn, actuates the gears
of the gear assembly 236 to produce a corresponding rotation or
displacement of the pinion gear 238, which, in turn, displaces the
shaft 224 in direction 250. In this manner, the rotary shaft 402
translates rotation (or displacement) of the rotor 530 into a
corresponding rotation (or displacement) of the gear assembly 236
such that the exposed teeth 239 of the pinion gear 238 to apply
force to the exposed teeth 225 of the shaft 224 of the plunger 222
in the direction 250 of the fluid delivery port 210 to thereby
displace the plunger 222 in the direction 250 of the fluid delivery
port 210 and dispense, expel, or otherwise deliver fluid from the
barrel 220 of the reservoir 206 to the user via the fluid delivery
path provided by the cannula 208.
[0049] Referring to FIG. 5, in an exemplary embodiment, a sensor
500 is configured to measure, sense, or otherwise detect rotation
(or displacement) of the rotary shaft 402 and/or the rotor 530 of
the motor 232. For convenience, but without limitation, the motor
position sensor 500 may alternatively be referred to herein as a
motor position sensor or rotor position sensor. In exemplary
embodiments, the rotary shaft 402 includes a detectable feature
that is measurable or otherwise detectable by the motor position
sensor 500. In the illustrated embodiment, a rotary member (or
wheel) 502 is provided on the rotary shaft 402 and includes a
plurality of protruding features (or arms) 504 that are measurable
or otherwise detectable by the motor position sensor 500. In the
illustrated embodiment, the wheel 502 is coaxial and/or concentric
to and disposed about the rotary shaft 402, and the wheel 502 is
affixed to or otherwise integrated with the rotary shaft 402 such
that the wheel 502 and the rotary shaft 402 rotate in unison. In
this manner, rotation (or displacement) of the wheel 502
corresponds to the displacement of the rotary shaft 402 and/or the
rotor 530 of the motor 232.
[0050] In exemplary embodiments, the sensor 500 is realized as an
incremental position sensor configured to measure, sense, or
otherwise detect incremental rotations of the rotary shaft 402
and/or the rotor 530 of the motor 232. For example, in accordance
with one or more embodiments, the sensor 500 is realized as a
rotary encoder. In alternative embodiments, the sensor 500 may be
realized using any other suitable sensor, such as (but not limited
to) a magnetic sensor, optical sensor (or other light detector),
tactile sensor, capacitive sensor, inductive sensor, and/or the
like. In exemplary embodiments, the incremental position sensor 500
may be configured to count or otherwise sense incremental rotations
of the motor 232 via the wheel 502, for example, by counting each
time a protruding feature 504 passes by the sensor 500. In this
regard, when the number of protruding features 504 equals or
otherwise corresponds to the number of discrete motor steps of the
stepper motor 232, the incremental position sensor 500 counts or
otherwise senses the number of motor steps traversed by the rotary
shaft 402 and/or rotor of the motor 232. In some embodiments, the
sensor 500 includes an emitter 510 and a detector 512 disposed on
opposite sides of the wheel 502 such that at least a portion of the
protruding features 504 passes between the emitter 510 and the
detector 512 as the wheel 502 rotates. In this regard, the sensor
500 may detect or otherwise count each instance when a protruding
feature 504 interrupts a transmission from the emitter 510 to the
detector 512. Alternatively, the sensor 500 may detect or otherwise
count each instance a transmission from the emitter 510 to the
detector 512 is uninterrupted or otherwise completed (e.g., via
gaps between protruding features 504).
[0051] Still referring to FIGS. 2-6, as described in greater detail
below in the context of FIGS. 7-12, in exemplary embodiments, to
allow the position of the plunger 222 and/or shaft 224 to be
monitored, measured, or otherwise detected, the shaft 224 includes
one or more detectable features provided or otherwise formed
thereon and a voided portion of the durable housing 202 that
corresponds to or otherwise surrounds the shaft 224 includes a
sensing arrangement capable of sensing or otherwise detecting the
one or more detectable features on the shaft 224. In this regard,
when the reservoir 206 is inserted in the durable housing 202, the
sensing arrangement is disposed proximate the shaft 224 to sense or
otherwise detect the one or more detectable features on the shaft
224. In exemplary embodiments, the sensing arrangement provides an
electrical output signal that is indicative of or otherwise
corresponds to the position or location of the detectable
feature(s), which in turn, corresponds to the position or location
of the shaft 224 relative to the durable housing 202, which, in
turn, corresponds to the position or location of the plunger 222
within the barrel 220 of the reservoir 206. For example, in one or
more embodiments, the detectable feature influences an electrical
characteristic (e.g., a resistance, capacitance, inductance, or the
like) of the sensing arrangement based on the position of the
detectable feature with respect to the sensing arrangement. In this
manner, an electrical output signal from the sensing arrangement is
influenced by the detectable features on the shaft 224 and is
thereby indicative of the position or location of the shaft 224.
Additionally, when the shaft 224 is integral with the plunger 222
or another feature of the reservoir 206, the electrical output
signal from the sensing arrangement that is influenced by the
detectable features on the shaft 224 is also indicative of the
reservoir 206 being seated within the housing 202 and/or device
200. In one or more alternative embodiments, the detectable
feature(s) may be optically detected, for example, using a
photodiode or the like, that is provided in the durable housing
202. In yet other embodiments, the detectable feature(s) may have a
magnetic field or another electromagnetic characteristic that is
detected or otherwise sensed by corresponding sensors provided in
the durable housing 202 (e.g., Hall effect sensors, capacitive
sensors, inductive sensors, and the like). It should be noted that
there are numerous potential sensing techniques and/or
configurations that may be utilized to sense, measure, or otherwise
detect the position of the shaft 224 relative to the durable
housing 202, and the exemplary sensing configurations described
herein are provided for purposes of explanation and are not
intended to be exhaustive or limiting. In this regard, the subject
matter described herein is not limited to a particular sensing
technique described herein.
[0052] FIG. 7 illustrates an exemplary embodiment of a durable
housing 700 including a sensing arrangement 702 that may be
utilized as the durable housing 202 in the fluid infusion device
200 of FIG. 2, and FIG. 8 illustrates an exemplary embodiment of a
reservoir 800 that includes a shaft portion 802 having a feature
804 that is detectable by the sensing arrangement 702 in the
housing 700. The durable housing 700 and the reservoir 800 are
similar to the durable housing 202 and the fluid reservoir 206
described above in the context of FIGS. 2-6, and the common
features and/or functionality of the durable housing 700 and the
reservoir 800 will not be redundantly described in detail in the
context of FIGS. 7-8. As described above, the reservoir 800
includes a barrel 806 having a plunger 808 (or stopper) disposed
therein that is mechanically coupled to a shaft 810 having exposed
teeth 812 configured to engage the exposed teeth of a pinion gear
710 in the housing 700.
[0053] In the illustrated embodiment of FIG. 8, the reservoir 800
includes a guide portion 814 encompassing the shaft 810 that
includes a first cutout portion 816 to expose at least some of the
teeth 812 of the shaft 810 and a second cutout portion 818 to
expose or otherwise accommodate the detectable feature 804. As
illustrated in FIG. 7, the housing 700 includes a voided region 704
(or cavity) adapted to receive the reservoir 800 that includes a
first portion 706 that corresponds to the barrel 806 of the
reservoir 800 and a second portion 708 that corresponds to the
shaft portion 802 of the reservoir 800. The pinion gear 710 is
positioned within the housing 700 such that the exposed teeth of
the pinion gear 710 extend into the voided shaft portion 708 to
engage the teeth 812 of the reservoir 800 when the reservoir 800 is
inserted in the voided region 704. In an exemplary embodiment, the
sensing arrangement 702 is formed in (or on) a wall of the voided
shaft portion 708 so that the sensing arrangement 702 is proximate
to (or adjacent to) the shaft portion 802 of the reservoir 800 when
the reservoir 800 is inserted in the voided region 704.
[0054] In accordance with one or more exemplary embodiments, the
detectable feature 804 is provided on the side of the shaft 810
that faces the sensing arrangement 702 at or near the distal end of
the shaft 810, that is, the end of shaft 810 distal to the plunger
808 and/or barrel 806. In this manner, when the shaft 810 and/or
plunger 808 is fully retracted (e.g., when the reservoir 800 is
full of fluid), the detectable feature 804 is at or near the distal
end of the sensing arrangement 702. Thus, as the shaft 810 and/or
plunger 808 is displaced to deliver fluid from the reservoir, the
detectable feature 804 approaches the end of the sensing
arrangement 702 proximate the barrel 806 and produces a
corresponding change in the electrical output signal generated by
the sensing arrangement 702. In this manner, the position of the
detectable feature 804 relative to the sensing arrangement 702
functions as a proxy for the position of the plunger 808 with
respect to the barrel 806, thereby allowing the amount of fluid
remaining in the reservoir 800 to be estimated based at least in
part on the sensed position of the detectable feature 804.
[0055] As described in greater detail below in the context of FIGS.
9-10, in accordance with one embodiment, the sensing arrangement
702 is realized as a resistive sensing arrangement having a
variable resistance that is influenced by a location (or position)
of the detectable feature 804 with respect to the sensing
arrangement. For example, the resistive sensing arrangement may
include one or more layers of material that, when compressed,
provide a resistance corresponding to the location (or position) on
the sensing arrangement 702 where the one or more layers are
compressed. In this regard, the detectable feature 804 may be
realized as a protruding feature, such as a peg or pin, that
extends from the shaft 810 through the cutout portion 818 to
contact the sensing arrangement 702 and compress the one or more
layers to produce a resistance corresponding to the position of the
protruding feature with respect to the sensing arrangement 702. In
this regard, as the shaft 810 is displaced in response to rotation
of the pinion gear 710, the location (or position) of the
protruding feature changes by a corresponding amount to compress
the layers of the sensing arrangement 702 at a different location
to produce a corresponding change in the resistance of the sensing
arrangement 702.
[0056] In accordance with another embodiment, the sensing
arrangement 702 is realized as a capacitive sensing arrangement
having a variable capacitance corresponding to a location (or
position) of the detectable feature 804 with respect to the sensing
arrangement 702. In this regard, the detectable feature 804 may be
realized as a conductive material, such as a metal material, that
provides a capacitance or a change in capacitance between the
detectable feature 804 and the sensing arrangement 702. In this
regard, as the shaft 810 is displaced in response to rotation of
the pinion gear 710, the location (or position) of the detectable
feature 804 changes by a corresponding amount to vary the
capacitance of the capacitive sensing arrangement in a manner that
corresponds to the location of the detectable feature 804 with
respect to the sensing arrangement 702. In alternative embodiments,
the sensing arrangement 702 may be realized as an inductive sensing
arrangement having a variable inductance corresponding to a
location (or position) of the detectable feature 804 with respect
to the sensing arrangement 702.
[0057] FIGS. 9-10 depict an exemplary embodiment of a resistive
sensing arrangement 900 suitable for use as the sensing arrangement
702 in the durable housing 700 of FIG. 7. The sensing arrangement
900 includes, without limitation, a bottom conductive layer 902, a
spacer layer 904, an upper conductive layer 906, and an adhesive
layer 908. A flexible cover layer 910 is provided overlying the
layers 902, 904, 906, 908 to seal the layers 902, 904, 906, 908
within the housing 700 and protect the sensing arrangement 900 from
environmental elements that could interfere with its operation. In
exemplary embodiments, the cover layer 910 is realized as a thin
layer of flexible yet resilient material (which may or may not be
the same material as the remainder of the housing 700) that is
capable of being flexed without permanent deformation, such as a
polycarbonate polybutylene terephthalate (PC/PBT) blend material,
that, in turn, is affixed to, joined to, or otherwise integral with
the surrounding surfaces of the housing 700 that define the voided
shaft portion 708 to seal the remaining layers 902, 904, 906, 908
within the housing 700. In this regard, the cover layer 910 may be
understood as being part of the housing 700. The bottom conductive
layer 902 is realized as a substantially rigid material having a
conductive resistive carbon ink layer 920 deposited or otherwise
formed thereon. In accordance with one embodiment, the bottom
conductive layer 902 is realized as a layer of FR-4 printed circuit
board (PCB) material. The upper conductive layer 906 is realized as
a flexible material having another conductive resistive carbon ink
layer 930 deposited or otherwise formed on the bottom surface that
corresponds to or is otherwise aligned with the resistive carbon
ink layer 920 on the upper surface of the bottom conductive layer
902. The spacer layer 904 is realized as two longitudinal portions
914 of a rigid material that are affixed to the upper surface of
the bottom conductive layer 902 and the bottom surface of the upper
conductive layer 906 along the edges of the conductive layers 902,
906 such that conductive layers 902, 906 are spaced apart from one
another in the absence of a compressive force applied to the upper
surface of the upper conductive layer 906. The adhesive layer 908
is affixed to the upper surface of the upper conductive layer 906
and the bottom surface of the cover layer 910 so that the
underlying layers 902, 904, 906 of the sensing arrangement 900 are
affixed to the cover layer 910.
[0058] Referring now to FIGS. 7-10, in an exemplary embodiment, the
cover layer 910 is integrated with or otherwise provided on a wall
of the voided shaft portion 708 that faces the detectable feature
804 on the shaft 810. In this regard, the resistive carbon ink
layers 920, 930 are positioned on the conductive layers 902, 906
such that they are substantially aligned with the detectable
feature 804. When the sensing arrangement 702 is realized as the
sensing arrangement 900, the detectable feature 804 is realized as
a protruding feature that contacts the cover layer 910 when the
reservoir 800 is provided within the voided region 704 of the
housing 700. The protruding feature 804 on the shaft 810 compresses
the cover layer 910 and the upper conductive layer 906 and causes
the resistive carbon ink layers 920, 930 to contact one another at
the location where the protruding feature 804 contacts the sensing
arrangement 900. In this regard, the contact between the resistive
carbon ink layers 920, 930 provides a resistive electrical
connection between the conductive layers 902, 906. In an exemplary
embodiment, the bottom resistive carbon ink layer 920 is configured
as a voltage divider, wherein the magnitude of the voltage across
the resistive carbon ink layer 920 is influenced by the resistance
of the resistive carbon ink layer 920 between an end of the sensing
arrangement 900 and the location where the protruding feature 804
contacts the sensing arrangement 900, which corresponds to the
length of the resistive carbon ink layer 920 between the end of the
sensing arrangement 900 and the location where the protruding
feature 804 contacts the sensing arrangement 900. In this manner,
as the protruding feature 804 moves closer to and/or further from
the end of the sensing arrangement 900, the voltage across the
resistive carbon ink layer 920 and/or the sensing arrangement 900
increases and/or decreases by a corresponding amount, and is
thereby indicative of the position of the shaft 810 with respect to
the sensing arrangement 702, 900 and/or the housing 700.
[0059] FIG. 11 depicts an exemplary embodiment of a control system
1100 suitable for use with an infusion device in an infusion
system, such as infusion device 200 or infusion device 102 in the
infusion system 100. The illustrated control system 1100 includes,
without limitation, a control module 1102, a pulse-width modulation
(PWM) module 1104, a motor driver module 1106, a motor 1108 (e.g.,
motor 232), and a motor (or rotor) position sensor 1110 (e.g.,
sensor 500). In exemplary embodiments, the control system 1100 is
suitably configured to operate the motor 1108 to displace a plunger
1160 and provide a desired amount of fluid to a user in response to
a dosage command indicative of the desired amount of fluid to be
delivered that is received from a pump control system 1120, as
described in greater detail below. In this regard, the pump control
system 1120 generally represents the electronics and other
components of the infusion system that process sensor data (e.g.,
from sensing arrangement 104) pertaining to a condition of the user
and control operation of the fluid infusion device according to a
desired infusion delivery program in a manner that is influenced by
sensor data measured by and/or received from the sensing
arrangement 104 or otherwise dictated by the user. In practice, the
features and/or functionality of the pump control system 1120 may
be implemented by control electronics located in the fluid infusion
device 102, 200, the CCD 106 and/or the computer 108. It should be
understood that FIG. 11 is a simplified representation of the
system 1100 for purposes of explanation and is not intended to
limit the subject matter described herein in any way. For example,
in practice, the features and/or functionality of the control
module 1102 may implemented by or otherwise integrated into the
pump control system 1120, or vice versa.
[0060] In the illustrated embodiment, the PWM module 1104 generally
represents the combination of circuitry, hardware and/or other
electrical components configured to generate a pulse-width
modulated voltage output applied to the motor 1108 via the motor
driver module 1106. In an exemplary embodiment, the PWM module 1104
is coupled to an energy source 1130, such as a battery housed
within the infusion device 200 (e.g., in the housing 202), to
receive a supply voltage. Based on a duty cycle setting for the PWM
module 1104, the PWM module 1104 generates or otherwise produces a
pulse-width modulated voltage output that oscillates between the
supply voltage provided by the energy source 1130 and a ground (or
reference) voltage over a time interval (e.g., the PWM period),
wherein the pulse-width modulated voltage output is equal to the
supply voltage for a percentage of the time interval corresponding
to the duty cycle setting. For example, if the supply voltage
provided by the energy source 1130 is equal to five volts and the
duty cycle setting is equal to 30%, then the pulse-width modulated
voltage output generated by the PWM module 1104 may be a square
wave having a magnitude equal to five volts for 30% of the time
interval and zero volts for the remaining 70% of the time interval.
In this regard, the duty cycle setting corresponds to the width of
a portion of the square wave (e.g., the portion corresponding the
supply voltage), and accordingly, the duty cycle setting may
alternatively be referred to herein as the PWM width setting. As
described in greater detail below, in exemplary embodiments, the
control module 1102 is coupled to the PWM module 1104 to adjust,
modify, or otherwise control the duty cycle setting of the PWM
module 1104.
[0061] In an exemplary embodiment, the motor 1108 is a stepper
motor or brushless DC motor having a toothed rotor and a number of
sets of windings, wherein the number of teeth on the rotor along
with the number of winding sets and the physical arrangement of the
winding sets with respect to the rotor teeth provides a finite
number of motor steps within a revolution of the rotor. In this
regard, as used herein, a "motor step" or any variant thereof
should be understood as referring to an incremental rotation of the
rotor of the motor 1108 that is dictated by the number of teeth of
the rotor along with the number and/or arrangement of the winding
sets. As described above in the context of FIGS. 2-6, in an
exemplary infusion pump embodiment, the rotor of the motor 1108 is
mechanically coupled to the plunger 1160 via a gear assembly 1140
(e.g., gear assembly 236) and a shaft 1150 (e.g., shaft 224 or
shaft 810). In this regard, the gear assembly 236 includes gears
and/or other drive train components configured to translate
rotation of the rotor of the motor 1108 into a corresponding amount
of displacement of the shaft 1150, which in turn, displaces the
plunger 1160 (e.g., plunger 222 or plunger 808) into the barrel
(e.g., barrel 206 or barrel 806) of a reservoir (e.g., reservoir
206 or reservoir 800) to deliver fluid (e.g., insulin) to the body
of a user.
[0062] The control system 1100 also includes one or more detectable
features 1180 associated with the shaft 1150 and a sensing
arrangement 1170 capable of sensing, measuring, or otherwise
detecting the relative position of the detectable feature(s) 1180.
As described above in the context of FIG. 8, in accordance with one
or more embodiments, the detectable feature(s) 1180 are formed on
or otherwise integrated into the shaft 1150, however, in other
embodiments, the detectable feature(s) 1180 may be separate from
the shaft. For example, as described in greater detail below in the
context of FIG. 13, one or more detectable feature(s) may be
provided inside the guide portion 814 so that a portion of the
shaft 810 may be interposed between the detectable feature(s) and
the sensing arrangement 702 to influence the ability of the sensing
arrangement 702 to sense, measure, or otherwise detect by
detectable feature(s) in a manner that corresponds to the amount of
the shaft 810 that is interposed between the detectable feature(s)
and the sensing arrangement 702. The control module 1102 is coupled
to the sensing arrangement 1170 utilizes the position of the
detectable feature(s) 1180 sensed by the sensing arrangement 1170
to obtain a measured position of the shaft 1150 and utilizes the
measured shaft position to determine the amount of fluid remaining
in the reservoir and/or identify anomalous conditions, as described
in greater detail below in the context of FIG. 12.
[0063] Still referring to FIG. 11, the motor driver module 1106
generally represents the combination of circuitry, hardware and/or
other electrical components configured to sequentially apply a
voltage provided at a supply voltage input of the motor driver
module 1106 to one or more sets of windings of the motor 1108 in a
particular order to produce a corresponding number of commanded
motor steps of rotation by the motor 1108. In the illustrated
embodiment, the supply voltage input of the motor driver module
1106 is coupled to the output of the PWM module 1104, such that the
motor driver module 1106 provides the pulse-width modulated voltage
from the PWM module 1104 to the one or more sets of windings of the
motor 1108 in a particular order under control of the control
module 1102. In this regard, in some embodiments, the motor driver
module 1106 is coupled to the control module 1102 to receive a
commanded number of motor steps from the control module 1102,
wherein in response to the commanded number of motor steps, the
motor driver module 1106 sequentially applies the pulse-width
modulated voltage from the PWM module 1104 to the sets of windings
of the motor 1108 in the appropriate order to produce the commanded
number of motor steps. In other embodiments, the control module
1102 may operate the switches and/or other circuitry of the motor
driver module 1106 to produce the commanded number of motor steps.
The frequency at which the motor driver module 1106 is operated
(e.g., the frequency at which the pulse-width modulated voltage is
changed from being applied to one winding set to another winding
set) is less than the frequency of the pulse-width modulated
voltage output from the PWM module 1104, such that the pulse-width
modulated voltage output oscillates between the supply voltage and
the ground voltage multiple times over the time period (e.g., the
inverse of the motor driver frequency) during which the pulse-width
modulated voltage output is applied to a particular set of windings
of the motor 1108.
[0064] In an exemplary embodiment, the motor position sensor 1110
is realized as an incremental position sensor, such as a rotary
encoder, that is configured to sense, measure, or otherwise detect
an incremental rotation of the rotor of the motor 1108, in a
similar manner as described above in the context of the sensor 500
of FIG. 5. In exemplary embodiments, the resolution of the position
sensor 1110 is greater than or equal to the resolution of the motor
1108, that is, the number of discrete incremental rotations
measurable by the position sensor 1110 over one revolution of the
rotor of the motor 1108 (e.g., the number of detectable features
504) is greater than or equal to the number of discrete motor steps
over one revolution of the rotor of the motor 1108. In accordance
with one or more embodiments, the output of the position sensor
1110 is coupled to the control module 1102 to provide dynamic
closed-loop PWM control of the motor 1108, as described in greater
detail below.
[0065] Still referring to FIG. 11, the control module 1102
generally represents the hardware, software, firmware and/or
combination thereof that is configured to receive or otherwise
obtain a commanded dosage from the pump control system 1120,
convert the commanded dosage to a commanded number of motor steps,
and command, signal, or otherwise operate the motor driver module
1106 to cause the motor 1108 to produce the commanded number of
motor steps. As described in greater detail below in the context of
FIG. 12, in exemplary embodiments, the control module 1102 obtains
or otherwise determines the measured position of the shaft 1150 via
the sensing arrangement 1170 and estimates or otherwise determines
an amount of fluid remaining in a fluid reservoir based on the
corresponding position of the plunger 1160. Additionally, the
control module 1102 determines an expected position of the shaft
based on the commanded number of motor steps and/or the commanded
dosage, and determines whether an occlusion condition or some other
anomalous condition exists when a difference between the expected
position of the shaft and the measured position exceeds a threshold
amount. Depending on the embodiment, the control module 1102 may be
implemented or realized with a general purpose processor, a
microprocessor, a controller, a microcontroller, a state machine, a
content addressable memory, an application specific integrated
circuit, a field programmable gate array, any suitable programmable
logic device, discrete gate or transistor logic, discrete hardware
components, or any combination thereof, designed to perform the
functions described herein. Furthermore, the steps of a method or
algorithm described in connection with the embodiments disclosed
herein may be embodied directly in hardware, in firmware, in a
software module executed by the control module 1102, or in any
practical combination thereof. In exemplary embodiments, the
control module 1102 includes or otherwise accesses a memory,
including any sort of random access memory (RAM), read only memory
(ROM), flash memory, registers, hard disks, removable disks,
magnetic or optical mass storage, or any other short or long term
storage media or other non-transitory computer-readable medium,
which is capable of storing programming instructions for execution
by the control module 1102. The computer-executable programming
instructions, when read and executed by the control module 1102,
cause the control module 1102 to perform the tasks, operations,
functions, and processes described in greater detail below.
[0066] FIG. 12 depicts an exemplary control process 1200 suitable
for implementation by the control system 1100 to monitor the
position of the shaft 1150 and/or plunger 1160 while operating an
infusion device to deliver fluid to a user. The various tasks
performed in connection with the control process 1200 may be
performed by software, hardware, firmware, or any combination
thereof. For illustrative purposes, the following description
refers to elements mentioned above in connection with FIG. 11. In
practice, portions of the control process 1200 may be performed by
different elements of the control system 1100, such as, for
example, the control module 1102, the PWM module 1104, the motor
driver module 1106, the motor 1108, the position sensor 1110, the
detectable feature(s) 1180 and/or the sensing arrangement 1170. It
should be appreciated that the control process 1200 may include any
number of additional or alternative tasks, the tasks need not be
performed in the illustrated order and/or the tasks may be
performed concurrently, and/or the control process 1200 may be
incorporated into a more comprehensive procedure or process having
additional functionality not described in detail herein. Moreover,
one or more of the tasks shown and described in the context of FIG.
12 could be omitted from a practical embodiment of the control
process 1200 as long as the intended overall functionality remains
intact.
[0067] In accordance with one or more embodiments, the control
process 1200 begins by detecting or otherwise identifying the
presence of a reservoir in the infusion device using the sensing
arrangement (task 1202). For example, as described above in the
context of FIGS. 7-10, in accordance with one or more embodiments,
when the reservoir 800 is provided within the voided region 704 of
the housing 700 and the housing 700 is coupled to a base plate
(e.g., base plate 204), the sensing arrangement 702, 900 is capable
of sensing or otherwise detecting the presence of the detectable
feature 804 in contact with or otherwise proximate to the sensing
arrangement 702, 900. In this regard, the control module 1102
monitors or otherwise obtains the electrical output signal from the
sensing arrangement 1170 to determine whether the presence of a
detectable feature 1180 has been detected. In accordance with one
embodiment, the control module 1102 detects or otherwise identifies
seating of the reservoir by obtaining the electrical output signal
from the sensing arrangement 1170 and determining the reservoir is
seated within the housing of the infusion device when the
electrical output signal is indicative of the detectable feature
1180 contacting the housing of the infusion device or otherwise
being within a threshold distance of the sensing arrangement 1170.
For example, when the sensing arrangement 1170 generates an
electrical output signal in response to physical contact with the
detectable feature 1180 on the shaft 1150 (e.g., resistive sensing
arrangement 900), the control module 1102 detects seating of the
reservoir when the sensing arrangement 1170 generates an electrical
output signal indicating presence of the detectable feature 1180.
In other embodiments, when the sensing arrangement 1170 generates
an electrical output signal based on the proximity of the
detectable feature 1180 on the shaft 1150, the control module 1102
may detect seating of the reservoir when the sensing arrangement
1170 generates an electrical output signal indicating that the
detectable feature 1180 of the shaft 1150 is within a threshold
distance of the sensing arrangement 1170 that indicates the
reservoir is seated. In accordance with one or more embodiments, in
response to detecting the initial seating of the reservoir, the
control module 1102 automatically initiates a priming sequence or
the like to initialize the positioning of the plunger 1160 within
the reservoir for subsequent operation.
[0068] In an exemplary embodiment, after the presence of the
reservoir is detected, the control process 1200 continues by
operating the motor to achieve a displacement of the plunger
corresponding to a desired dosage of fluid to be administered to a
user (task 1204). In this regard, the control module 1102 obtains
commands from the pump control system 1120 corresponding to the
desired dosage and operates the motor 1108 to rotate the rotor by
an amount that produces an amount of displacement of the shaft 1150
and/or plunger 1160 that corresponds to the desired dosage. For
example, the pump control system 1120 may determine or otherwise
receive (e.g., from the CCD 106 and/or the computer 108) a dose (or
bolus) of fluid to be provided to the user based on a sensed
condition of the user (e.g., a blood glucose level). In some
embodiments, the pump control system 1120 converts the amount of
fluid to be provided to the user into a commanded displacement of
the plunger 1160, converts the commanded displacement of the
plunger 1160 to a corresponding number of motor steps (or
incremental rotations) based on the relationship between one motor
step of rotation and the resulting linear displacement of the shaft
1150 and/or plunger 1160, and provides that commanded number of
motor steps to the control module 1102. In other embodiments, the
pump control system 1120 provides the amount of fluid to be
provided to the user to the control module 1102, wherein the
control module 1102 converts the commanded dosage into a
corresponding number of commanded motor steps based on the amount
of displacement of the plunger 1160 corresponding to that amount of
fluid.
[0069] In accordance with one or more embodiments, the control
module 1102 utilizes closed-loop dynamic PWM control by dynamically
adjusting the duty cycle setting of the PWM module 1104 to ensure
the rotor rotates by the commanded amount. For example, the control
module 1102 may determine an expected number of incremental
rotations of the rotor of the motor 1108 that should be measured by
the position sensor 1110 based on the commanded number of motor
steps corresponding to the commanded dosage. After operating the
motor driver module 1106 to produce the commanded number of motor
steps of rotation, the control module 1102 obtains a measured
number of incremental rotations of the rotor of the motor 1108 from
the position sensor 1110, and based on differences between the
measured number and the expected number of incremental rotations,
increases or otherwise adjusts the PWM width setting of the PWM
module 1104 to achieve the commanded number of motor steps during
subsequent operation of the motor 1108.
[0070] After operating the motor to achieve a desired displacement
of the plunger, the control process 1200 continues by obtaining a
measured position of the shaft using the sensing arrangement and
estimating or otherwise determining the amount of fluid remaining
in the fluid reservoir based on the measured position of the shaft
(tasks 1206, 1208). In this regard, when the detectable feature(s)
1180 are provided on the plunger 1160, the control module 1102
obtains, from the sensing arrangement 1170, electrical signals
indicative of the position of the detectable feature(s) 1180 with
respect to the sensing arrangement 1170 and/or the durable housing.
For example, when the sensing arrangement 1170 is realized as the
resistive sensing arrangement 900, the control module 1102 may
obtain a voltage across the sensing arrangement 900 (which is
influenced by the resistance of the sensing arrangement 900, which,
in turn, is influenced by the position of the detectable feature
804 on the shaft 810) and determine the position of the shaft
relative to the sensing arrangement 900 based on that obtained
voltage relative to a reference voltage or the voltage(s) across
the sensing arrangement 900 when the detectable feature is located
at the end(s) of the sensing arrangement 900. Based on the measured
position of the shaft relative to the sensing arrangement 1170
and/or the durable housing, the control module 1102 may determine
or otherwise estimate the corresponding position of the plunger
1160 within the barrel of the reservoir, and based on the position
of the plunger 1160 within the barrel of the reservoir, determine
or otherwise estimate the amount of fluid remaining in the
reservoir. For example, a calibration procedure may be performed to
compress the resistive carbon ink layers 920, 930 into contact at
specific locations associated with the shaft position for known
amounts of fluid remaining in the reservoir to correlate the
resulting electrical output signals generated by the resistive
sensing arrangement 900 to the respective remaining amounts of
fluid. The relationship between the electrical output signals and
the remaining amounts of fluid (or contact locations) may be
interpolated and/or extrapolated (e.g., by performing linear
regression or another suitable regression technique) to
characterize the electrical output signal generated by the
resistive sensing arrangement 900 as a function of the remaining
amount of fluid in the reservoir (or a particular location where
the resistive carbon ink layers 920, 930 are in contact). In this
manner, a calibration table may be created that correlates values
for remaining amounts of fluid in the reservoir and/or shaft
positions to values of the electrical output signal generated by
the resistive sensing arrangement 900 over the potential range of
displacement for the shaft. Thus, the control module 1102 may
utilize the calibration table to correlate the electrical output
signal obtained from the sensing arrangement 1170 to an estimated
amount of fluid remaining in the reservoir. In accordance with one
or more embodiments, the control module 1102 may provide the
estimated amount of fluid remaining in the reservoir to the pump
control system 1120 for display or presentation to the user (e.g.,
via CCD 106 and/or computer 108).
[0071] As described in greater detail below in the context of FIG.
13, in some embodiments, the control module 1102 may augment the
measured position of the shaft 1150 obtained using the sensing
arrangement 1170 with a number of incremental rotor rotations
measured by the position sensor 1110 to improve the resolution of
the estimated amount of fluid. For example, if the detectable
feature(s) 1180 and/or the sensing arrangement 1170 are configured
to provide discrete measurements of the shaft position (e.g., as
opposed to the continuous measurement range provided by sensing
arrangement 900), the control module 1102 may utilize incremental
rotations measured by the position sensor 1110 to estimate or
otherwise determine the measured position of the plunger 1160 when
the shaft position is between two discrete measurement positions.
In this regard, the sensing arrangement 1170 may be comprised of a
plurality of sensing elements, wherein the control module 1102
utilizes incremental rotations measured by the position sensor 1110
to estimate or otherwise determine the measured position of the
plunger 1160 when the shaft position is between or overlaps two
sensing elements. For example, the control module 1102 may
implement a counter that counts the incremental rotations detected
by the position sensor 1110 and is reset each time the detectable
feature 1180 changes between discrete positions measurable by the
sensing arrangement 1170 (e.g., each time the detectable feature
1180 passes from one sensing element to another). The value of the
counter may be used to determine the position of the shaft 1150
and/or plunger 1160 based on the position of the detectable feature
1180 relative to the next discrete position, that is, the amount by
which the detectable feature 1180 is offset from a current and/or
previous discrete position. For example, the control module 1102
may convert the value of the counter into an offset amount of
displacement based on the relationship between an incremental
rotation of the rotor and a corresponding linear displacement of
the shaft 1150 (e.g., the displacement of the shaft 1150 that would
result from an incremental rotation of the rotor), and add or
subtract the offset amount from the position of the detectable
feature 1180 measured by the sensing arrangement 1170.
[0072] Still referring to FIG. 12, in an exemplary embodiment, the
control process 1200 continues by determining whether the estimated
amount of remaining fluid is less than a threshold amount of fluid
indicative of a low fluid volume condition in the reservoir and
generating or otherwise providing a notification when the estimated
amount of remaining fluid is less than the threshold amount (tasks
1210, 1212). In this regard, the threshold amount of fluid may be
configured or otherwise chosen by a user of the fluid infusion
device 102, 200 (e.g., using the CCD 106 and/or the computer 108)
to correspond to a level of fluid in the reservoir where the user
would like to be reminded or otherwise notified to refill or
replace the reservoir. In some embodiments, the control module 1102
provides a notification of the low fluid volume condition to the
pump control system 1120 or another supervisory system or module
(e.g., the CCD 106 and/or the computer 108) in response to
determining the estimated amount of fluid remaining is less than
the threshold amount. For example, the control module 1102 may
generate an interrupt signal that is handled by the pump control
system 1120. In response to the notification from the control
module 1102, the pump control system 1120 may generate an auditory
and/or visual alert to the user, for example, by causing the CCD
106 and/or the computer 108 to generate one or more auditory cues
(e.g., a beep) or display one or more visual cues to notify the
user of the low fluid volume condition.
[0073] In an exemplary embodiment, the control process 1200
continues by determining an expected position of the shaft and/or
plunger based on the commanded rotation of the motor and
determining whether a difference between the expected position of
the shaft and/or plunger and the measured position of the shaft
and/or plunger obtained using the sensing arrangement is greater
than a threshold amount (tasks 1214, 1216). In this regard, the
threshold amount is indicative of a difference between the measured
shaft position and the expected shaft position that indicates that
the drive system and/or motor 1108 is not displacing the shaft
and/or plunger in the desired manner due to an anomalous condition,
such as a fluid path occlusion or a drive system anomaly (e.g., a
stripped or slipped gear). The control module 1102 may determine
the expected position of the plunger 1160 by obtaining an initial
position of the shaft (e.g., via the sensing arrangement 1170)
prior to operating the motor 1108 to produce a commanded rotation,
converting the commanded rotation to a corresponding displacement
of the plunger 1160 based on the relationship between the motor
steps (or incremental rotations) for the motor 1108 and the linear
displacement of the shaft 1150, and add or subtract that resulting
displacement to the initial shaft position to obtain the expected
shaft position after the motor 1108 has been operated to produce
the commanded rotation. In other embodiments, the control module
1102 may convert the number of incremental rotations measured by
the position sensor 1110 to an expected displacement of the shaft
1150 based on the relationship between an incremental rotation
detected by the position sensor 1110 and the corresponding linear
displacement of the shaft 1150, and add or subtract that expected
displacement to the initial position. In an exemplary embodiment,
when the difference between the expected position of the shaft
and/or plunger and the measured position of the shaft and/or
plunger is less than the threshold amount, the control process 1200
repeats the loop defined by tasks 1202, 1204, 1206, 1208, 1210,
1212, 1214 and 1216 throughout operation of the fluid infusion
device to deliver fluid to the user and notify the user when the
reservoir should be replaced and/or refilled. In this regard, in
accordance with one or more embodiments, whenever the control
process 1200 fails to detect presence of the reservoir, the control
process 1200 generates or otherwise provides a notification
indicative of an anomalous condition within the fluid infusion
device (e.g., task 1224). For example, the control module 1102 may
indicate that the reservoir has become unseated to the pump control
system 1120, which, in turn provides a notification to the user
(e.g., by generating an auditory and/or visual alert) so that the
user may reseat the reservoir.
[0074] Still referring to FIG. 12, in an exemplary embodiment, when
the difference between the expected position of the shaft and/or
plunger and the measured position of the shaft and/or plunger is
greater than the threshold amount, the control process 1200
continues by obtaining an axial force aligned with the shaft and/or
plunger and determining whether the axial force exceeds a threshold
force value indicative of a fluid path occlusion (tasks 1218,
1220). For example, the fluid infusion device may include a force
sensor configured to measure axial forces applied by the shaft 1150
and/or plunger 1160 in a direction aligned with the longitudinal
axis of the shaft 1150 (e.g., direction 250). In this regard, the
force sensor may be positioned within the durable housing (e.g.,
within the gear assembly 236) such that the force sensor is
subjected to a reactionary compressive force when the drive system
and/or motor is operated to displace the shaft 1150 and/or plunger
1160 in the axial direction in opposition to the fluid pressure in
the reservoir. Thus, if an occlusion develops within the fluid path
that blocks fluid delivery from the fluid infusion device to the
body of the user, the fluid pressure increases as the shaft 1150
and/or plunger 1160 is forced forward in the axial direction by the
motor 1108, which, in turn, increases the force applied to the
force sensor. However, if an anomalous condition exists within the
drive system and/or fluid infusion device that decouples the shaft
1150 and/or plunger 1160 from the motor 1108, such as a stripped or
slipped gear or another drive system anomaly, rotation of the rotor
of the motor 1108 displaces the shaft 1150 and/or plunger 1160 by a
reduced amount (if at all) and the force sensor will not be
subjected to rapidly increasing forces as the motor 1108 is
operated as compared to an occlusion condition. Accordingly, when
the axial force measured by the force sensor is greater than the
threshold force value indicative of a fluid path occlusion and the
difference between the expected shaft position and measured shaft
position exceeds the threshold amount, the control process 1200
detects or otherwise identifies an occlusion condition and
generates or otherwise provides a notification indicative of the
occlusion condition (task 1222). Conversely, when the difference
between the expected shaft position and measured shaft position
exceeds the threshold amount but the axial force measured by the
force sensor is less than the occlusion threshold force value, the
control process 1200 detects or otherwise identifies a drive system
anomaly or some other anomalous condition (e.g., a stripped gear)
in the infusion device and generates or otherwise provides a
notification indicative of the anomalous condition within the fluid
infusion device (task 1224).
[0075] In accordance with one or more embodiments, the control
module 1102 is coupled to the force sensor and provides a
notification of an anomalous condition in the drive system to the
pump control system 1120 or another supervisory system or module
(e.g., the CCD 106 and/or the computer 108) when the axial force
measured by the force sensor is less than the threshold force
indicative of a fluid path occlusion and the difference between the
expected position and the measured position of the shaft and/or
plunger is greater than a threshold amount. In response, the pump
control system 1120 may generate an auditory and/or visual alert to
the user to notify the user of the anomalous condition. Conversely,
the control module 1102 may provide a notification of an occlusion
condition to the pump control system 1120 when the axial force
measured by the force sensor is greater than the threshold force
and the difference between the expected position and the measured
position of the shaft and/or plunger is greater than the threshold
amount, wherein the pump control system 1120 generates an auditory
and/or visual alert to the user to notify the user of the occlusion
condition in response to the notification from the control module
1102. In other embodiments, the control module 1102 generates or
otherwise provides a notification to the pump control system 1120
when the difference between the expected position and the measured
position of the shaft and/or plunger exceeds the threshold amount,
wherein the pump control system 1120 is coupled to the force sensor
and determines whether the difference between the expected position
and the measured position of the shaft and/or plunger is
attributable to a fluid path occlusion or another anomalous
condition, such as a drive system anomaly. In this manner, the
difference between the expected position and the measured position
of the shaft and/or plunger may be used to monitor the health of
the drive system while also verifying, confirming, or otherwise
augmenting occlusion detection algorithms and/or techniques
performed by the pump control system 1120 and/or the fluid infusion
device.
[0076] FIG. 13 depicts another exemplary embodiment of a durable
housing 1300 of a fluid infusion device suitable for use with the
reservoir 800 of FIG. 8. The housing 1300 includes a sensing
arrangement 1302 having a plurality of discrete sensing elements
1304 formed in (or on) a wall of the voided shaft portion 1308 so
that the sensing elements 1304 are proximate to (or adjacent to)
the shaft portion 802 of the reservoir 800 when the reservoir 800
is inserted in the housing 1300. It should be noted that although
FIG. 13 depicts the sensing elements 1304 as being visible, in
exemplary embodiments, a cover layer (similar to cover layer 910)
may be provided overlying the sensing arrangement 1302 to retain
the sensing arrangement 1302 within the durable housing 1300 and/or
protect the sensing elements 1304 from environmental elements. The
output of an individual sensing element 1304 indicates a discrete
position of the shaft 810 and/or the detectable feature 804 with
respect to the sensing arrangement 1302 and/or the housing 1300.
For example, when the detectable feature 804 is aligned with and/or
proximate the first sensing element 1310, the first sensing element
1310 may output an electrical signal (e.g., a voltage or current)
that indicates the detectable feature 804 is aligned with and/or
proximate the first sensing element 1310 while the remaining
sensing elements 1304 output electrical signals that indicate the
detectable feature 804 is not aligned with and/or proximate the
remaining sensing elements 1304. In response to displacement of the
shaft 810 that causes the detectable feature 804 to be aligned with
and/or proximate a second sensing element 1312, the second sensing
element 1312 outputs an electrical signal that indicates the
detectable feature 804 is aligned with and/or proximate the second
sensing element 1312 while the remaining sensing elements 1304
output electrical signals that indicate the detectable feature 804
is not aligned with and/or proximate the remaining sensing elements
1304. For example, when the detectable feature 804 is aligned with
the first sensing element 1310, the first sensing element 1310 may
output a logical high voltage that indicates the detectable feature
804 is aligned with the first sensing element 1310 and the second
sensing element 1312 may output a logical low voltage that
indicates the detectable feature 804 is not aligned with the second
sensing element 1312 until the detectable feature 804 is aligned
with the second sensing element 1312, at which point the second
sensing element 1312 outputs a logical high voltage. Once the
detectable feature 804 is no longer aligned with the first sensing
element 1310, the outputs a logical low voltage indicating the
detectable feature 804 is no longer aligned with the first sensing
element 1310. It should be noted that in some embodiments, for
improved resolution, the detectable feature 804 may be configured
to overlap or otherwise be sensed by adjacent sensing elements 1304
concurrently, or alternatively, the sensing elements 1304 may be
positioned or otherwise arranged so that the detectable feature 804
is capable of overlapping or otherwise being sensed by adjacent
sensing elements 1304 concurrently. For example, both sensing
arrangements 1310, 1312 may output a logical high voltage when the
detectable feature 804 is aligned between the first sensing
arrangement 1310 and the second sensing arrangement 1312, thereby
indicating the detectable feature 804 is positioned between the
sensing elements 1310, 1312.
[0077] As described above in the context of FIG. 12, in accordance
with one or more embodiments, when the sensing arrangement 1170 is
realized as sensing arrangement 1302, the control module 1102
implements a counter that counts the incremental rotations detected
by the position sensor 1110 and is reset each time the detectable
feature 804 passes from one sensing element 1304 to another. For
example, the control module 1102 may reset the counter when the
output signal from the second sensing element 1312 changes state
(e.g., from logical low voltage to logical high voltage) and use
the value of the counter to determine the position of the
detectable feature 1180 relative to the second sensing element 1312
and/or the third sensing elements 1314, thereby improving the
resolution of the measured shaft position.
[0078] In accordance with one embodiment, the sensing elements 1304
are realized as magnetic sensing elements, such as Hall effect
sensors or the like, and the detectable feature 804 is realized as
a magnet or another magnetic element formed on or in the shaft 810.
In this regard, the magnetic field of the magnetic element 804
influences the state of the magnetic sensing elements 1304 based on
the position of the magnetic element 804 relative to the magnetic
sensing elements 1304, and thereby, the output electrical signals
generated by the magnetic sensing elements 1304 are indicative of
the relative position of the magnetic element 804 and/or shaft
810.
[0079] In accordance with another embodiment, the sensing elements
1304 are realized as an optical sensing element, such as a
photodiode or another photodetector. In this regard, the detectable
feature 804 may be realized as a reflective feature (e.g., a
portion of reflective material, a mirror, or the like) or another
optical feature that is detectable by the optical sensing elements
1304. In some embodiments, the sensing arrangement 1302 and/or
sensing elements 1304 may also include a radiation source, such as
a light-emitting diode (LED) or the like, that emits
electromagnetic radiation that is directed towards the shaft 810
and/or shaft portion 802 and reflected by the optical feature 804
to the sensing element 1304 aligned with the optical feature 804.
In some embodiments, the radiation source may emit a reference
electromagnetic signal having one or more reference signal
characteristics that is directed towards the optical feature 804,
wherein the optical feature 804 modulates or otherwise modifies one
or more signal characteristics of the reference signal to produce a
modified signal that is reflected and sensed, measured, or
otherwise received by the sensing element(s) 1304. In this regard,
the optical feature 804 may be configured so that the signal
characteristics of the reflected signal(s) sensed, measured, or
otherwise received by the sensing element(s) 1304 may correspond to
the position of the shaft 810. For example, the optical feature 804
may be provided along the length of the shaft 810 and configured so
that the intensity of the reflected signal received by the sensing
element 1318 proximate the barrel 806 increases as the shaft 810
and/or plunger 808 is displaced further into the barrel 806.
[0080] In accordance with yet another embodiment, the sensing
elements 1304 are realized as optical sensing elements, wherein the
optically detectable feature is provided on an interior of the
guide portion 814 of the reservoir 800. For example, the interior
wall of the guide portion 814 that faces the sensing arrangement
1302 when the reservoir 800 is provided in the housing 1300 may
include one or more reflective features and/or other optical
features that are detectable by the optical sensing elements 1304
via the cutout portion 818 as the as the shaft 810 and/or plunger
808 is displaced further into the barrel 806. For example, in
accordance with one embodiment, the interior walls of the guide
potion 814 include a reflective material provided thereon and the
sensing arrangement 1302 may include one or more radiation sources
to direct electromagnetic radiation into the interior of the guide
portion 814 via the cutout portion 818, wherein the intensity of
the electromagnetic signals reflected back to the sensing elements
1304 via the cutout portion 818 increases as the as the shaft 810
and/or plunger 808 is displaced further into the barrel 806 and
exposes a greater portion of the reflective material on the
interior of the guide portion 814 and allows a greater amount of
electromagnetic radiation to be reflected back out of the guide
portion 814.
[0081] Still referring to FIG. 13, in accordance with one
embodiment, the interior of the guide portion 814 may include a
single detectable feature at or near the end of the guide portion
proximate the barrel 806 of the reservoir 800 that is detectable by
the sensing element 1318 proximate the barrel region of the housing
1300 when the shaft 810 is at or near a fully depressed position
within the barrel 806 of the reservoir 800, and is thereby utilized
to detect or otherwise obtain a measured position of the shaft 810
corresponding to the plunger 808 being at or near a fully depressed
position within the barrel 806. In such an embodiment, additional
sensing elements 1310, 1312, 1314, 1316 need not be present inside
the housing 1300. When the sensing element 1318 proximate the
barrel region of the housing 1300 detect the detectable feature
inside the guide portion 814, the control module 1102 may obtain or
otherwise identify the measured shaft position as corresponding to
the shaft 810, 1150 being at or near a fully depressed position
within the barrel 806, and thereby determine that the remaining
amount of fluid is less than the threshold amount and generate
notification of a low fluid volume condition in a similar manner as
described above.
[0082] Turning now to FIGS. 14-15, in accordance with one or more
embodiments, a durable housing 1400 of a fluid infusion device
includes a magnetic sensing arrangement 1402 including plurality of
magnetic sensing elements 1404 suitable for use with a reservoir
1500 having a plurality of magnetic elements 1504, 1506, 1508
provided on its shaft 1502. In the illustrated embodiment, the
magnetic sensors 1404 are realized as Hall effect sensors provided
on a circuit board 1410 that is disposed within the housing 1400
and covered or otherwise contained by a cover layer.
[0083] In exemplary embodiments, the magnetic elements 1504, 1506,
1508 are realized as magnets having alternate polarity. For
example, the magnetic element 1504 at the distal end of the shaft
1502 may have its magnetic north pole facing the magnetic sensing
arrangement 1402, with the adjacent magnetic element 1506 having
its magnetic south pole facing the magnetic sensing arrangement
1402 and the magnetic element 1508 closest to the barrel portion of
the reservoir 1500 having its magnetic north pole facing the
magnetic sensing arrangement 1402. In a similar manner as described
above in the context of FIG. 13, the outputs of the magnetic
sensors 1404 indicate the relative locations of the magnetic
elements 1504, 1506, 1508 with respect to the sensing arrangement
1402 and/or housing 1400, which, in turn, indicates the position of
the shaft 1502 with respect to the barrel portion of the reservoir
1500. In this regard, increasing the number of detectable features
(e.g., magnetic elements 1504, 1506, 1508) combined with increasing
the number of individual sensing elements (e.g., magnetic sensors
1404) improves the resolution for determining the shaft
position.
[0084] FIG. 16 depicts another embodiment of a reservoir 1600
suitable for use with the housing 1400 of FIG. 14. The reservoir
1600 includes a single magnetic element 1604 on the shaft 1602 near
the end of the shaft 1602 distal to the barrel of the reservoir
1600. The length of the magnetic element 1604 (e.g., the dimension
of the magnetic element 1604 along the longitudinal axis of the
shaft 1602) is greater than a sum of the length of an individual
magnetic sensor 1404 and the distance between adjacent magnetic
sensors 1404 so that the magnetic element 1604 concurrently
overlaps or is otherwise aligned with multiple magnetic sensors
1404 when the reservoir 1600 is disposed within the housing 1400.
As described above, a counter may be implemented that counts the
incremental rotations detected by a position sensor and is reset
each time the output of the next magnetic sensor 1404 closer to the
barrel of the reservoir 1600 changes state to determine the shaft
position.
[0085] Turning now to FIGS. 17-18, in accordance with one or more
embodiments, a durable housing 1700 of a fluid infusion device
includes an inductive sensing arrangement 1702 including plurality
of inductive sensing elements 1704 suitable for use with a
reservoir 1800 having a resonator 1804 provided on the end of its
shaft 1802 that is distal to the barrel of the reservoir 1800. In
the illustrated embodiment, the inductive sensing elements 1704 are
realized as inductive sensors including one or more wires that
zigzag relatively perpendicular to the longitudinal axis of the
shaft 1802 of the reservoir 1800, wherein the inductive sensing
elements 1704 are provided on a circuit board 1710 that is disposed
within the housing 1700 and covered or otherwise contained by a
cover layer. In exemplary embodiments, the resonator 1804 is
affixed to the distal end of the shaft 1802 and includes an
inductor 1806 that is affixed or otherwise mounted to a capacitor
1808, with the inductor 1806 and capacitor 1808 being configured
electrically in series with one another to provide a resonant
circuit. When the resonator 1804 overlaps or is otherwise aligned
with an inductive sensing element 1704, the output of the inductive
sensing element 1704 indicates the relative position of the
resonator 1804, which, in turn, indicates the position of the shaft
1802.
[0086] Turning now to FIGS. 19-20, in accordance with one or more
embodiments, a durable housing 1900 of a fluid infusion device
includes an optical sensing arrangement 1902 suitable for use with
a reservoir 2000 having a plurality of reflective elements 2004,
2006 provided on its shaft 2002. The optical sensing arrangement
1902 includes a plurality of light emitting elements 1904 and
corresponding light detecting elements 1906 that are arranged along
a longitudinal axis of a circuit board 1910 that corresponds to the
longitudinal axis of the shaft 2002. The light emitting elements
1904 and the light detecting elements 1906 are oriented towards the
shaft 2002 so that the light emitting elements 1904 direct light
towards the shaft 2002 and the light detecting elements 1906 detect
or otherwise sense the portion of the light reflected back towards
the optical sensing arrangement 1902 by the reflective elements
2004, 2006 on the shaft 2002. In an exemplary embodiments, the
light emitting elements 1904 are realized as light emitting diodes
and the light detecting elements 1906 are realized as photodiodes
which are mounted to a circuit board 1910 that is disposed within
the housing 1900 and covered or otherwise contained by a
transparent cover layer.
[0087] As illustrated in FIG. 20, in exemplary embodiments, a first
reflective element 2004 is disposed near the end of the shaft 2002
that is distal to the barrel and the second reflective element 2006
is disposed near the end of the shaft 2002 that is proximate to the
barrel. In this regard, when the reservoir 2000 is full, the
reflective elements 2004, 2006 are aligned with or otherwise
overlap the pairs of elements 1904, 1906 that are near the ends of
the circuit board 1910. In accordance with one embodiment, when the
optical sensing arrangement 1902 detects light reflected by both
reflective elements 2004, 2006, a control system coupled to the
optical sensing arrangement 1902 (e.g., control module 1102)
determines that the reservoir 2000 is full. As described above, as
the shaft 2002 is displaced in the axial direction toward and/or
into the barrel, the reflective element 2004 at the distal end of
the shaft 2002 overlaps one or more of the light detecting elements
1906, thereby providing an indication of the relative position of
the shaft 2002.
[0088] Turning now to FIGS. 21-22, in accordance with one or more
embodiments, a durable housing 2100 of a fluid infusion device
includes an optical sensing arrangement 2102 suitable for use with
a reservoir 2200 having an optically detectable pattern 2204
provided on its shaft 2202. The optical sensing arrangement 2102
includes a pair of light emitting elements 2104, such as light
emitting diodes, disposed near opposing ends of an optical array
sensor 2106, with the light emitting elements 2104 and optical
array sensor 2106 being mounted or otherwise provided on a circuit
board 2110 that is disposed within the housing 2100 and covered or
otherwise contained by a transparent cover layer. The light
emitting elements 2104 and the optical array sensor 2106 are
oriented towards the shaft 2202 so that the light emitting elements
2104 direct light towards the shaft 2202 and the optical array
sensor 2106 detects the pattern 2204 provided on the shaft 2202. In
the illustrated embodiment, the pattern 2204 on the shaft 2202 is
graduated so that the width of the pattern 2204 linearly increases
towards the distal end of the shaft 2202. In this regard, the
output of the optical array sensor 2106 is indicative of the width
of the portion of the pattern 2204 that overlaps or is otherwise
aligned with the optical array sensor 2106, and thus, is indicative
of the relative position of the shaft 2202 with respect to the
barrel of the reservoir 2200. In a similar manner as described
above, a calibration procedure may be performed to correlate the
output of the optical array sensor 2106 to the respective remaining
amounts of fluid based on width of the portion of the pattern 2204
aligned with the optical array sensor 2106 at specific locations
associated with shaft positions for known amounts of fluid
remaining in the reservoir 2200. The relationship between the
output of the optical array sensor 2106 and the remaining amounts
of fluid may be interpolated and/or extrapolated to characterize
the output generated by the optical array sensor 2106 as a function
of the remaining amount of fluid in the reservoir, and a
calibration table may be created that correlates values for
remaining amounts of fluid in the reservoir and/or shaft positions
to values of the output generated by the optical array sensor 2106
over the potential range of displacement for the shaft 2202.
[0089] FIG. 23 depicts another embodiment of a reservoir 2300
suitable for use with the housing 2100 of FIG. 21. The shaft 2302
of the reservoir 2300 includes a plurality of optically
distinguishable portions 2304, 2306, 2308. In accordance with one
embodiment, each portion 2304, 2306, 2308 of the shaft 2302 has a
different color. For example, the portion 2308 of the shaft 2302
proximate the barrel may be colored red and the portion 2304 of the
shaft 2302 distal to the barrel may be colored blue, with the
intermediate portion 2306 of the shaft 2302 being colored green. In
this regard, the relative position of the shaft 2302 (or the
corresponding amount of fluid remaining in the reservoir 2300) may
be determined based on the wavelength of light detected by the
optical sensor 2106. For example, when the average wavelength
detected by the optical sensor 2106 indicates the red portion 2308
of the shaft 2302 is primarily aligned with the optical sensor
2106, the amount of fluid remaining in the reservoir 2300 may be
determined to be within a first range (e.g., greater than 150
units). Similarly, when the average wavelength detected by the
optical sensor 2106 indicates the intermediate portion 2306 of the
shaft 2302 is primarily aligned with the optical sensor 2106, the
amount of fluid remaining in the reservoir 2300 may be determined
to be within a second range (e.g., between 50 and 150 units), and
when the average wavelength detected by the optical sensor 2106
indicates the end portion 2304 of the shaft 2302 is primarily
aligned with the optical sensor 2106, the amount of fluid remaining
in the reservoir 2300 may be determined to be within a third range
(e.g., less than 50 units remaining). In this manner, the optically
distinguishable portions 2304, 2306, 2308 provide a coarse
measurement of the position of the shaft 2302.
[0090] The foregoing description may refer to elements or nodes or
features being "connected" or "coupled" together. As used herein,
unless expressly stated otherwise, "coupled" means that one
element/node/feature is directly or indirectly joined to (or
directly or indirectly communicates with) another
element/node/feature, and not necessarily mechanically. In
addition, certain terminology may also be used in the herein for
the purpose of reference only, and thus is not intended to be
limiting. For example, terms such as "first", "second", and other
such numerical terms referring to structures do not imply a
sequence or order unless clearly indicated by the context.
[0091] While at least one exemplary embodiment has been presented
in the foregoing detailed description, it should be appreciated
that a vast number of variations exist. It should also be
appreciated that the exemplary embodiment or embodiments described
herein are not intended to limit the scope, applicability, or
configuration of the claimed subject matter in any way. For
example, the subject matter described herein is not limited to the
infusion devices and related systems described herein. Moreover,
the foregoing detailed description will provide those skilled in
the art with a convenient road map for implementing the described
embodiment or embodiments. It should be understood that various
changes can be made in the function and arrangement of elements
without departing from the scope defined by the claims, which
includes known equivalents and foreseeable equivalents at the time
of filing this patent application.
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