U.S. patent application number 14/573220 was filed with the patent office on 2015-06-18 for system and method for motion-controlled foot unit.
The applicant listed for this patent is Ossur hf. Invention is credited to Arinbjorn Viggo Clausen, Helgi Jonsson, Heidrun Gigja Ragnarsdottir, Hjordis Thorhallsdottir.
Application Number | 20150164661 14/573220 |
Document ID | / |
Family ID | 34890463 |
Filed Date | 2015-06-18 |
United States Patent
Application |
20150164661 |
Kind Code |
A1 |
Ragnarsdottir; Heidrun Gigja ;
et al. |
June 18, 2015 |
SYSTEM AND METHOD FOR MOTION-CONTROLLED FOOT UNIT
Abstract
A system and method associated with the movement of a limb. In
one example, the system, such as a prosthetic or orthotic system,
includes an actuator that actively controls, or adjusts, the angle
between a foot unit and a lower limb member. A processing module
may control movement of the actuator based on data obtained from a
sensor module. For instance, sensing module data may include
information relating to the gait of a user and may be used to
adjust the foot unit to substantially mimic the movement of a
natural, healthy ankle. The system may further accommodate, for
example, level ground walking, traveling up/down stairs, traveling
up/down sloped surfaces, and various other user movements. In
addition, the processing module may receive user input or display
output signals through an external interface. For example, the
processing module may receive a heel height input from the
user.
Inventors: |
Ragnarsdottir; Heidrun Gigja;
(Reykjavik, IS) ; Clausen; Arinbjorn Viggo;
(Reykjavik, IS) ; Thorhallsdottir; Hjordis;
(Reykjavik, IS) ; Jonsson; Helgi; (Reykjavik,
IS) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ossur hf |
Reykjavik |
|
IS |
|
|
Family ID: |
34890463 |
Appl. No.: |
14/573220 |
Filed: |
December 17, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12891085 |
Sep 27, 2010 |
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14573220 |
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11056344 |
Feb 11, 2005 |
7811334 |
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12891085 |
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60544259 |
Feb 12, 2004 |
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60588232 |
Jul 15, 2004 |
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Current U.S.
Class: |
623/24 |
Current CPC
Class: |
A61F 2002/6685 20130101;
A61F 2002/7645 20130101; A61F 2002/704 20130101; A61F 2/68
20130101; A61F 2002/6642 20130101; A61F 2002/705 20130101; A61F
2/6607 20130101; A61F 2/72 20130101; A61F 2013/00455 20130101; A61F
2002/764 20130101; A61F 2002/5073 20130101; A61F 2002/7635
20130101; A61F 2002/701 20130101; A61F 2002/5018 20130101; A61F
2/66 20130101 |
International
Class: |
A61F 2/68 20060101
A61F002/68; A61F 2/66 20060101 A61F002/66 |
Claims
1-23. (canceled)
24. A method of controlling operation of a prosthetic ankle device
comprising a foot unit and a lower limb member rotatably connected
to each other about a pivot location, the method comprising:
collecting data with one or more sensors located on the prosthetic
ankle device while the prosthetic ankle device is connected either
to a tibial stump of a transtibial amputee or to a separate
prosthetic knee device worn by a transfemoral amputee, while a user
of the prosthetic ankle device is moving; processing data received
from the one or more sensors to determine a current state of
locomotion for the prosthetic ankle device; and when the prosthetic
ankle device is determined to be in a stance position, actuating an
actuator to input a mechanical motion to rotate the foot unit
relative to the lower limb member such that an angle between the
foot unit and the lower limb member increases toward a
plantarflexion position toward the end of the stance phase.
25. The method of claim 24, further comprising, when the prosthetic
ankle device is determined to be in the stance position, actuating
the actuator to input a mechanical motion to rotate the foot unit
relative to the lower limb member such that the angle between the
foot unit and the lower limb member decreases toward a dorsiflexion
position before increasing the angle toward a plantarflexion
position.
26. The method of claim 24, further comprising changing the angle
between the foot unit and the lower limb member toward a
dorsiflexion position at the beginning of swing phase after the
angle is increased toward the end of stance phase.
27. The method of claim 24, wherein the prosthetic ankle device
comprises an attachment pyramid attaching the prosthetic ankle
device either to the amputated stump of the transtibial amputee or
to the separate prosthetic knee device at a location below the
natural or artificial knee joint of the user.
28. The method of claim 27, wherein the actuator is located below
the attachment pyramid.
29. The method of claim 24, wherein the actuator is located behind
the lower limb member and is attached at a first end to an upper
end of the lower limb member and at a second end to the foot unit
behind the pivot location between the foot unit and the lower limb
member.
30. The method of claim 24, wherein the actuator comprises a motor
that provides a pushing or pulling force to the foot unit with
respect to the lower limb member to change the angle between the
foot unit and the lower limb member.
31. The method of claim 24, wherein the prosthetic ankle device is
connected to a tibial stump of a transtibial amputee.
32. The method of claim 24, wherein the prosthetic ankle device is
connected to a separate prosthetic knee device of a transfemoral
amputee.
33. The method of claim 32, wherein the prosthetic ankle device is
connected to a prosthetic knee comprising a second actuator
separate from the actuator of the prosthetic ankle device.
34. The method of claim 24, wherein the motor is powered by a
battery located on the prosthetic ankle device.
35. The method of claim 24, wherein the data is collected with one
or more accelerometers.
36. The method of claim 24, wherein the data is collected with one
or more pressure sensors.
Description
RELATED APPLICATIONS
[0001] The present application is a continuation application of
U.S. patent application Ser. No. 12/891,085, filed Sep. 27, 2010,
which is a continuation application of U.S. patent application Ser.
No. 11/056,344, filed Feb. 11, 2005, issued as U.S. Pat. No.
7,811,334, and entitled "SYSTEM AND METHOD FOR MOTION-CONTROLLED
FOOT UNIT", which claims the benefit of priority under 35 U.S.C.
.sctn.119(e) of U.S. Provisional Application No. 60/544,259, filed
Feb. 12, 2004, and entitled "LOWER LIMB PROSTHESIS WITH
ANKLE-MOTION-CONTROLLED FOOT," and U.S. Provisional Application No.
60/588,232, filed Jul. 15, 2004, and entitled "PROSTHETIC OR
ORTHOTIC SYSTEM WITH ANKLE-MOTION-CONTROLLED FOOT," each of which
is incorporated herein by reference in its entirety and is to be
considered a part of this specification.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] Preferred embodiments of this invention relate to systems
and methods having a motion-controlled limb and, in particular, an
ankle-motion-controlled foot.
[0004] 2. Description of the Related Art
[0005] Millions of individuals worldwide rely on prosthetic and/or
orthotic devices to compensate for disabilities, such as amputation
or debilitation, and to assist in the rehabilitation of injured
limbs. Orthotic devices include external apparatuses used to
support, align, prevent, protect, correct deformities of, or
improve the function of movable parts of the body. Prosthetic
devices include apparatuses used as artificial substitutes for a
missing body part, such as an arm or leg.
[0006] The number of disabled persons and amputees is increasing
each year as the average age of individuals increases, as does the
prevalence of debilitating diseases such as diabetes. As a result,
the need for prosthetic and orthotic devices is also increasing.
Conventional orthoses are often used to support a joint, such as an
ankle or a knee, of an individual, and movement of the orthosis is
generally based solely on the energy expenditure of the user. Some
conventional prostheses are equipped with basic controllers that
artificially mobilize the joints without any interaction from the
amputee and are capable of generating only basic motions. Such
basic controllers do not take into consideration the dynamic
conditions of the working environment. The passive nature of these
conventional prosthetic and orthotic devices typically leads to
movement instability, high energy expenditure on the part of the
disabled person or amputee, gait deviations and other short- and
long-term negative effects. This is especially true for leg
orthoses and prostheses.
SUMMARY OF THE INVENTION
[0007] Accordingly, one embodiment of the invention includes a
prosthetic or orthotic system that is self-powered and that mimics
the natural movement of a healthy limb, and in particular, the
movement of a healthy ankle. Another embodiment of the invention
includes a sensor system and a control system that manage the
motion of the prosthetic or orthotic system so as to facilitate
movement by the disabled person or amputee.
[0008] One embodiment of the invention includes a system associated
with the movement of a limb. In one embodiment, the system
comprises a foot unit; an attachment member having an upper end and
a lower end, wherein the lower end is pivotably attached to a first
location on the foot unit; and an actuator operatively coupled to
the foot unit and to the attachment member, wherein the actuator is
configured to actively adjust an angle between the attachment
member and the foot unit. For example, the foot unit may be a
prosthetic or orthotic device.
[0009] Another embodiment of the invention includes a prosthetic
system for mimicking the natural movement of an ankle. In one
embodiment, the prosthetic system comprises a prosthetic foot; a
pivot assembly attached to a first position on the prosthetic foot,
wherein the first position is near a natural ankle location of the
prosthetic foot; a lower limb member extending in a tibial
direction, the lower limb member having an upper end and a lower
end, wherein the lower end of the lower limb member is operatively
coupled to the pivot assembly; and an actuator operatively coupled
to the prosthetic foot and to the lower limb member, wherein the
actuator is configured to actively adjust an angle between the
lower limb member and the prosthetic foot about the pivot
assembly.
[0010] One embodiment of the invention includes a method for
controlling a device associated with the movement of a limb. In one
embodiment, the method comprises monitoring with at least one
sensor the movement of an actuatable device associated with a limb;
generating data indicative of said movement; processing the data
with a processing module to determine a current state of locomotion
of the actuatable device; and adjusting the actuatable device based
on the determined state of locomotion, wherein said adjusting
comprises substantially mimicking the movement of a healthy ankle.
For example, the actuatable device may be a prosthesis or an
orthosis.
[0011] Another embodiment of the invention includes a method for
controlling a prosthetic ankle device. In one embodiment, the
method comprises monitoring with at least one sensor the movement
of an actuatable prosthetic ankle device, wherein the at least one
sensor generates data indicative of the movement of the prosthetic
ankle device; receiving and processing the data with a control
module to determine a current state of locomotion of the actuatable
prosthetic ankle device; outputting with the control module at
least one control signal based on the determined state of
locomotion; and adjusting the actuatable prosthetic ankle device
based at least upon the control signal, wherein said adjusting
comprises substantially mimicking the movement of a healthy
ankle.
[0012] In one embodiment, a prosthetic or orthotic system is
provided having an ankle-motion-controlled foot. The prosthetic or
orthotic system comprises, among other things, a lower limb member,
an actuator, and a foot unit. The actuator is configured to mimic
the motion of an ankle by adjusting the angle between the lower
limb member and the foot unit. The prosthetic or orthotic system
also comprises an attachment portion that facilitates coupling of
the lower limb member to another prosthetic or orthotic member, to
the stump of an amputee, or to another component. The prosthetic or
orthotic system may also comprise a rechargeable battery to provide
power to the actuator or other components of the system.
Embodiments of the invention include systems for both transtibial
and transfemoral amputees.
[0013] In another embodiment of the invention, the prosthetic or
orthotic system comprises a sensor system that is used to capture
information regarding the position and movement of the prosthetic
or orthotic device. This information may be processed in real-time
so as to predict appropriate movements for the prosthetic or
orthotic device and to adjust the prosthetic or orthotic device
accordingly.
[0014] In one embodiment of the invention, a system architecture is
provided having a sensor module, a central processing unit, a
memory, an external interface, a control drive module, an actuator,
and an ankle device. The system architecture may receive
instructions and/or data from external sources, such as a user or
an electronic device, through the external interface.
[0015] In one embodiment, a control system may also be provided
that manages the movement of the orthosis or the prosthesis. In one
embodiment, the control system manages the movement of an actuator,
such as a screw motor. Such motion control provides for movement by
the user up inclined surfaces, down declines, or on stairs. In one
embodiment, the control system may be configured to monitor through
sensors the movements of a healthy limb and use the measurements to
control the movement of the prosthesis or orthosis. The control
system may also manage the damping of the actuator or other
portions of the orthosis or prosthesis.
[0016] In one embodiment, a method is provided for controlling
actuation of a prosthetic or orthotic device. The method comprises
providing one or more sensors on an actuatable prosthetic or
orthotic device. Data received from the sensors is processed and is
used to determine the current state of locomotion for the
prosthetic device. A processing unit, using at least a portion of
the data received from the sensors, then predicts movement of the
prosthetic or orthotic device. In one embodiment, a prosthetic
ankle is provided that mimics the movement of a healthy ankle. The
one or more sensors may comprise, for example, gyroscopes and/or
accelerometers. In another embodiment of the invention, adjustments
are not made to the actuatable prosthetic or orthotic device unless
the locomotion type of the user is determined by the processing
unit to have a security factor above a predetermined threshold
value.
[0017] In another embodiment, a method is provided for identifying
motion of an orthotic or prosthetic device. The method comprises
receiving data from one or more sensors placed on an orthotic or
prosthetic device while the device is moving. A waveform is
generated from the data received by the sensors. A specific motion
for the orthotic or prosthetic device is identified by correlating
the waveform with known waveforms for particular types of motion.
For example, known waveforms may be inputted by a user or
downloaded from an external device or system. The waveforms may
also be stored in a memory on the prosthetic or orthotic
device.
[0018] In another embodiment, a method is provided for actuating an
ankle-assisting device. The device is actuated by providing a
computer control to provide relative motion between a first and a
second portion of the device. In one embodiment, the device is an
orthosis. In another embodiment, the device is a prosthesis. In one
embodiment, the computer control predicts future motion of the
device. In another embodiment, the computer control receives input
from at least one sensor module that receives information regarding
environmental variables and/or the movement or position of the
prosthetic or orthotic device. In another embodiment, the computer
control receives input from at least one sensor module that
receives information regarding the movement or position of a
healthy limb.
[0019] For purposes of summarizing the invention, certain aspects,
advantages and novel features of the invention have been described
herein. It is to be understood that not necessarily all such
advantages may be achieved in accordance with any particular
embodiment of the invention. Thus, the invention may be embodied or
carried out in a manner that achieves or optimizes one advantage or
group of advantages as taught herein without necessarily achieving
other advantages as may be taught or suggested herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a perspective view of a lower limb prosthesis
having an ankle-motion-controlled foot unit according to one
embodiment of the invention.
[0021] FIG. 2 is a perspective view of the lower limb prosthesis of
FIG. 1, wherein a cover is removed to show inner components of the
prosthesis.
[0022] FIG. 3 is a side view of the lower limb prosthesis of FIG.
2.
[0023] FIG. 4 is a rear view of the lower limb prosthesis of FIG.
2.
[0024] FIG. 5 is a side view of the lower limb prosthesis of FIG. 1
with the cover shown partially removed, wherein the
ankle-motion-controlled foot is adjusted to accommodate an
incline.
[0025] FIG. 6 is a side view of a lower limb prosthesis of FIG. 5,
wherein the ankle-motion-controlled foot is adjusted to accommodate
a decline.
[0026] FIG. 7 is a schematic drawing indicating the correlation
between an ankle pivot point on an exemplifying embodiment of a
prosthetic foot unit with the natural ankle joint of a human
foot.
[0027] FIG. 8 is a graph depicting the range of ankle motion of an
exemplifying embodiment of a prosthetic or orthotic system during
one full stride on a level surface.
[0028] FIG. 9 is a block diagram of an exemplifying embodiment of a
control system architecture of a prosthetic or orthotic system
having an ankle-motion-controlled foot.
[0029] FIG. 10 is a table illustrating control signals usable to
adjust the ankle angle of a prosthetic or orthotic system according
to one embodiment of the invention.
[0030] FIG. 11 is a graph depicting an exemplifying embodiment of
the relationship between the control of a prosthetic or orthotic
system and the motion of a corresponding sound limb.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] Some preferred embodiments of the invention described herein
relate generally to prosthetic and orthotic systems and, in
particular, to prosthetic and orthotic devices having an
ankle-motion-controlled foot. While the description sets forth
various embodiment-specific details, it will be appreciated that
the description is illustrative only and should not be construed in
any way as limiting the invention. Furthermore, various
applications of the invention, and modifications thereto, which may
occur to those who are skilled in the art, are also encompassed by
the general concepts described herein.
[0032] The features of the system and method will now be described
with reference to the drawings summarized above. Throughout the
drawings, reference numbers are re-used to indicate correspondence
between referenced elements. The drawings, associated descriptions,
and specific implementation are provided to illustrate embodiments
of the invention and not to limit the scope of the invention.
[0033] The terms "prosthetic" and "prosthesis" as used herein are
broad terms and are used in their ordinary sense and refer to,
without limitation, any system, device or apparatus usable as an
artificial substitute or support for a body part.
[0034] The term "orthotic" and "orthosis" as used herein are broad
terms and are used in their ordinary sense and refer to, without
limitation, any system, device or apparatus usable to support,
align, prevent, protect, correct deformities of, immobilize, or
improve the function of parts of the body, such as joints and/or
limbs.
[0035] The term "ankle device" as used herein is a broad term and
is used in its ordinary sense and relates to any prosthetic,
orthotic or ankle-assisting device.
[0036] The term "transtibial" as used herein is a broad term and is
used in its ordinary sense and relates to without limitation any
plane, direction, location, or cross-section that is located at or
below a knee joint of a body, including artificial knee joints.
[0037] The term "transfemoral" as used herein is a broad term and
is used in its ordinary sense and relates to without limitation any
plane, direction, location, or cross-section that is located at or
above a knee joint of a body, including artificial knee joints.
[0038] The term "sagittal" as used herein is a broad term and is
used in its ordinary sense and relates to any description,
location, or direction relating to, situated in, or being in or
near the median plane (i.e., the plane divides the body lengthwise
into right and left halves) of the body or any plane parallel or
approximately parallel thereto. A "sagittal plane" may also refer
to any vertical anterior to posterior plane that passes through the
body parallel or approximately parallel to the median plane and
that divides the body into equal or unequal right and left
sections.
[0039] The term "coronal" as used herein is a broad term and is
used in its ordinary sense and relates to any description,
location, or direction relating to, situated in, or being in or
near the plane that passes through the long axis of the body. A
"coronal plane" may also refer to any plane that passes vertically
or approximately vertically through the body and is perpendicular
or approximately perpendicular to the median plane and that divides
the body into anterior and posterior sections.
[0040] FIG. 1 illustrates one embodiment of a lower limb prosthesis
100 having an ankle-motion-controlled foot with an attachment
member. The prosthesis 100 comprises an attachment member, in the
form of a lower limb member 102, operatively coupled to a foot unit
104. As used herein, the term "attachment member" is a broad term
and is used in its ordinary sense and in a prosthetic foot
embodiment relates to, without limitation, any member that attaches
either directly or indirectly to the foot unit 104 and is moveable
in relation thereto, for example by a pivoting motion, and is used
to attach the prosthesis 100 to a stump or intermediate prosthesis.
As illustrated, the attachment member may take the form of a lower
limb member in an ankle-prosthesis embodiment. In other
embodiments, for example an orthotic embodiment, the attachment
member may be used to attach to and support a body part, such as
with a brace, which also is moveably connected to a second member,
such as a foot unit, which would also attach to and support a body
part, such as the foot. In one embodiment, the lower limb member
102 is a generally elongated member with a main longitudinal axis
that extends in approximately a tibial direction, that is, a
direction that extends generally along the axis of a natural tibia
bone. For example, FIG. 1 depicts the lower limb member 102 as
being a generally vertical orientation.
[0041] In another embodiment, the lower limb member 102 may
comprise multiple sections. For example, the lower limb member 102
may comprise two elongated sections that extend approximately
parallel in a tibial direction and that are connected together. In
another embodiment, the lower limb member 102 comprises a two-sided
chamber having two substantially symmetrical parts to form a
partially enclosed housing. In another embodiment, the lower limb
member 102 may comprise a hollow member, such as a tube-like
structure. In other embodiments, the lower limb member 102 may
comprise elongated flat portions or rounded portions. In yet other
embodiments, the structure of the lower limb member 102 is not
elongated. For example, the lower limb member 102 may comprise a
generally circular, cylindrical, half-circular, dome-shaped, oval
or rectangular structure. One example of a possible lower limb
member is the ankle module and the structures described in U.S.
patent application Ser. No. 10/742,455, filed Dec. 18, 2003, and
entitled "PROSTHETIC FOOT WITH ROCKER MEMBER," the entirety of
which is hereby incorporated herein by reference and is to be
considered as part of this specification.
[0042] In one embodiment, the lower limb member 102 is generally
formed of a machine metal, such as aluminum, or a carbon fiber
material. In other embodiments of the invention, the lower limb
member 102 may comprise other materials that are suitable for
prosthetic devices. In one embodiment, the lower limb member 102
advantageously has a height between approximately 12 and 15
centimeters. In other embodiments of the invention, the lower limb
member 102 may have a height less than 12 centimeters or height
greater than 15 centimeters depending on the size of the user
and/or the intended use of the prosthesis 100. For example, the
lower limb member 102 may have a height of approximately 20
centimeters.
[0043] In one embodiment, the prosthesis 100 is configured such
that the main longitudinal axis of the lower limb member 102 is
substantially perpendicular to a lower surface of the foot unit 104
when the prosthesis 100 is in a resting position. In another
embodiment, the lower limb member 102 may be substantially
perpendicular to a level ground surface when the foot unit 104
rests on the ground. Such a configuration advantageously provides a
user with increased support and/or stability.
[0044] As depicted in FIG. 1, the lower limb member 102 further
comprises a cover 106. The cover 106 houses and/or protects the
inner components of the lower limb member 102. In another
embodiment, the cover 106 may be rounded or may be shaped in the
form of a natural human leg.
[0045] The lower limb member 102 further comprises an attachment
portion 108 to facilitate coupling of the lower limb member 102.
For example, as depicted in FIG. 1, the attachment portion 108 of
the lower limb member 102 couples the prosthesis 100 to a pylon
110. In other embodiments of the invention, the attachment portion
108 may be configured to couple the prosthesis 100 to a stump of an
amputee or to another prosthetic device. FIG. 1 also depicts a
control wire 112 usable to provide power to and/or communicate
control signals to the prosthesis 100.
[0046] The foot unit 104 may comprise various types of prosthetic
or orthotic feet. As illustrated in FIG. 1, the foot unit 104
incorporates a design described in Applicant's co-pending U.S.
patent application Ser. No. 10/642,125, entitled "LOW PROFILE
PROSTHETIC FOOT," and filed Aug. 15, 2003 the entirety of which is
hereby incorporated by reference and is to be considered as part of
this specification. For example, the foot unit 104 may comprise a
standard LP VARI-FLEX.RTM. unit available from Ossur.
[0047] In one embodiment, the foot unit 104 is configured to exert
a proportional response to weight or impact levels on the foot unit
104. In addition, the foot unit 104 may comprise shock absorption
for comfortable loading of the heel and/or for returning expended
energy. The foot unit 104 may comprise a full-length toe lever with
enhanced flexibility so as to provide a stride length for the
prosthetic limb that mimics the stride length of the healthy limb.
In addition, as depicted in FIG. 1, the foot unit 104 may comprise
a split-toe configuration, which facilitates movement on uneven
terrain. The foot unit 104 may also include a cosmesis or a foot
cover such as, for example, a standard Flex-Foot cover available
from Ossur.
[0048] FIG. 2 depicts the prosthesis 100 with the cover 106
removed. As shown, a lower end of the lower limb member 102 is
coupled to the foot unit 104 at a pivot assembly 114. As
illustrated, the lower limb member 102 is coupled to an ankle plate
103 of the foot unit 104, which extends generally rearward and
upward from a toe portion of the foot unit 104. The pivot assembly
114 allows for angular movement of the foot unit 104 with respect
to the lower limb member 102. For example, in one embodiment, the
pivot assembly 114 advantageously comprises at least one pivot pin.
In other embodiments, the pivot assembly 114 comprises a hinge, a
multi-axial configuration, a polycentric configuration,
combinations of the same or the like. Preferably, the pivot
assembly 114 is located on a portion of the foot unit 104 that is
near a natural ankle location of the foot unit 104. In other
embodiments of the invention, the pivot assembly 114 may be bolted
or otherwise releasably connected to the foot unit 104.
[0049] FIG. 2 further depicts the prosthesis 100 having an actuator
116. In one embodiment, the actuator 116 advantageously provides
the prosthesis 100 with the necessary energy to execute angular
displacements synchronized with the amputee's locomotion. For
example, the actuator 116 may cause the foot unit 104 to move
similar to a natural human foot. In one embodiment, the lower end
of the actuator 116 is coupled to the foot unit 104 at a first
attachment point 118. As illustrated, the foot attachment point 118
is advantageously located on the upper surface of the foot unit 104
on a posterior portion thereof. The upper end of the actuator 116
is coupled to the lower limb member 102 at a second attachment
point 120.
[0050] In one embodiment, the linear motion (or extension and
contraction) of the actuator 116 controls, or actively adjusts, the
angle between the foot unit 104 and the lower limb member 102. FIG.
2 depicts the actuator 116 comprising a double-screw motor, wherein
the motor pushes or pulls a posterior portion of the foot unit 104
with respect to the lower limb member 102. In other embodiments,
the actuator 116 comprises other mechanisms capable of actively
adjusting an angle, or providing for motion between, multiple
members. For example, the actuator 116 may comprise a single-screw
motor, a piston cylinder-type structure, a servomotor, a stepper
motor, a rotary motor, a spring, a fluid actuator, or the like. In
yet other embodiments, the actuator 116 may actively adjust in only
one direction, the angle between the lower limb member 102 and the
foot unit 104. In such an embodiment, the weight of the user may
also be used in controlling the angle caused by and/or the movement
of the actuator 116.
[0051] FIG. 2 illustrates the actuator 116 in a posterior
configuration, wherein the actuator 116 is located behind the lower
limb member 102. In other embodiments, the actuator 116 may be used
in an anterior configuration, wherein the actuator 116 is located
in front of the lower limb member 102. In another embodiment of the
invention, the actuator 116 comprises an auto adjusting ankle
structure and incorporates a design, such as described in U.S. Pat.
No. 5,957,981, the entirety of which is hereby incorporated by
reference and is to be considered as a part of this specification.
The particular configuration or structure may be selected to most
closely imitate the movement and location of a natural human ankle
joint and to facilitate insertion of the prosthesis 100 into an
outer cosmesis.
[0052] Furthermore, the actuator 116 is advantageously configured
to operate so as to not to emit loud noises, such as intermittent
noises, perceptible by the user and/or others. The actuator 116 may
also be configured to not operate or adjust if the prosthesis 100
experiences torque, such as in the sagittal plane, that exceeds a
certain level. For example, if the torque level exceeds four Newton
meters (Nm), the actuator 116 may cease to operate or may issue an
alarm.
[0053] The actuator 116 may also be substantially enclosed within
the cover 106 as shown in FIG. 1 such that the portions of the
actuator 116 are not visible and/or exposed to the environment. In
another embodiment, the actuator may be at least partially enclosed
by the lower limb member 102.
[0054] FIG. 2 further depicts control circuitry 122 usable to
control the operation of the actuator 116 and/or the foot unit 104.
In one embodiment, the control circuitry 122 comprises at least one
printed circuit board (PCB). The PCB may further comprise a
microprocessor. Software may also reside on the PCB so as to
perform signal processing and/or control the movement of the
prosthesis 100.
[0055] In one embodiment, the prosthesis 100 includes a battery
(not shown) that powers the control circuitry 122 and/or the
actuator 116. In one embodiment, the battery comprises a
rechargeable lithium ion battery that preferably has a power cycle
of at least 12 to 16 hours. In yet other embodiments, the power
cycle of the battery may be less than 12 hours or may be more than
16 hours. In other embodiments of the invention, the battery
comprises a lithium polymer battery, fuel cell technology, or other
types of batteries or technology usable to provide power to the
prosthesis 100. In yet other embodiments, the battery is removably
attached to a rear surface of the lower limb member 102, to other
portions of the prosthesis 100, or is located remote the prosthesis
100. In further embodiments, the prosthesis 100 may be connected to
an external power source, such as through a wall adapter or car
adapter, to recharge the battery.
[0056] In one embodiment, the prosthesis 100 is configured to lock
in a neutral position, such as the lower limb member 102 being
aligned generally vertical relative to a level ground surface when
the foot unit 104 is resting on the level ground surface, when the
battery is out of power or enters a low power stage. Such locking
provides for operational safety, reliability, and/or stability for
a user. The prosthesis 100 may also provide a battery status
display that alerts the user as to the status (i.e., charge) of the
battery. In another embodiment, the prosthesis 100 locks into a
substantially neutral position when the motion control functions of
the prosthesis 100 are turned off or disabled by a user.
[0057] As discussed above, a cosmesis material or other dressings
may be used with the prosthesis 100 so as to give the prosthesis
100 a more natural look or shape. In addition, the cosmesis,
dressings, or other filler material may be used to prevent
contaminants, such as dirt or water, from contacting the components
of the prosthesis 100.
[0058] FIG. 3 depicts a side view of the prosthesis 100 according
to one embodiment of the invention. As depicted in FIG. 3, the
actuator 116 further comprises a main housing 124, a lower
extendable portion 126, and an upper extendable portion 128. The
lower extendable portion 126 couples the main housing 124 of the
actuator 116 to the foot unit 104 at the first attachment point
118. The upper extendable portion 128 couples the main housing 124
of the actuator 116 to the lower limb member 102 at the second
attachment point 120. During operation and active adjustment of the
prosthesis 100, the lower extendable portion 126 and/or the upper
extendable portion 128 move into and/or out of the main housing 124
of the actuator 116 to adjust an angle between the foot unit 104
and the lower limb member 102.
[0059] For example, to increase an angle between the foot unit 104
and the lower limb member 102, the actuator 116 causes the lower
extendable portion 126 and/or the upper extendable portion 128 to
contract or withdraw into the main housing 124. For example, at
least one of the extendable portions 126, 128 may have a threaded
surface such that rotation in one direction (e.g., clockwise)
causes the extendable portion to withdraw into the main housing 124
of the actuator. In other embodiments, at least one of the
extendable portions 126, 128 comprises multiple telescoping pieces
such that, upon contraction, one of the multiple pieces of
extendable portion contracts into another of the multiple pieces
without withdrawing into the main housing 124. Likewise, to
decrease an angle between the foot unit 104 and the lower limb
member 102, the lower extendable portion 126 and/or the upper
extendable portion 128 may extend from the main housing 124.
[0060] In embodiments of the invention having an anterior
configuration for the actuator 116, extension of the lower
extendable portion 126 and/or the upper extendable portion 128
causes an increase in the angle between the lower limb member 102
and the foot unit 104. Likewise, a contraction of the lower
extendable portion 126 and/or the upper extendable portion 128
causes a decrease in the angle between the foot unit 104 and the
lower limb member 102.
[0061] FIG. 4 illustrates a rear view of the prosthesis 100
depicted in FIGS. 1-3. In other embodiments of the invention, the
cover 106 extends around the posterior portion of the prosthesis
100 to house at least a portion of the actuator 116 such that
portions of the actuator 116 are not visible and/or not exposed to
the environment.
[0062] FIGS. 5 and 6 illustrate one embodiment of the prosthesis
100 as it adjusts to inclines and declines. With reference to FIG.
5, the prosthesis 100 is depicted as adjusting to an incline. In
this embodiment, the actuator 116 extends so as to decrease an
angle .theta. between the lower limb member 102 and the foot unit
104 (or "dorsiflexion"). With respect to dorsiflexion, in one
embodiment, the angular range of motion of the prosthesis 100 is
from about 0 to 10 degrees from the neutral position. Other
embodiments may also facilitate exaggerated dorsiflexion during
swing phase.
[0063] FIG. 6 illustrates the prosthesis 100 as it adjusts to a
decline. The actuator 116 extends so as to increase the angle
.theta. between the lower limb member 102 and the foot unit 104 (or
"plantarflexion"). With respect to plantarflexion, in one
embodiment, the angular range of motion of the prosthesis 100 is
from about 0 to 20 degrees from the neutral position. Such
plantarflexion mimics natural ankle movement and provides for
greater stability to an amputee or a user. In one embodiment, the
total range of motion about the ankle pivot axis of the prosthesis
100, including both plantarflexion and dorsiflexion, is
approximately 30 degrees or more.
[0064] In addition to operating on inclines and declines, the
motion-controlled foot of the prosthesis 100 advantageously
accommodates different terrain, operates while traveling up and
down stairs, and facilitates level ground walking. In addition, the
prosthesis 100 may provide for automatic heel height adjustability.
Heel height may be measured, in one embodiment, from an ankle
portion of the lower limb member 102 to a ground surface when the
foot unit 104 is generally flat to the ground. For example, a user
may adjust to various heel heights, such as through pressing one or
more buttons, such that the prosthesis 100 automatically aligns
itself to the appropriate heel height. In one embodiment, the
prosthesis 100 includes a plurality of predetermined heel heights.
In yet other embodiments, the prosthesis 100 may automatically
adjust the heel height without the need for user input.
[0065] FIGS. 5 and 6 further illustrate one embodiment of the
attachment portion 108. The attachment portion 108 provides
alignment between the natural limb of the amputee and the
prosthesis 100 and may be configured so as to decrease pressure
peaks and shear forces. For example, the attachment portion 108 may
be configured to attach to another prosthesis, to the stump of the
amputee, or to another component. In one embodiment, the attachment
portion 108 comprises a socket connector. The socket connector may
be configured to receive a 32 mm-thread component, a male pyramid
type coupler, or other components. In other embodiments, the
attachment portion 108 may also comprise, or be configured to
receive, a female pyramid adapter.
[0066] As depicted in FIGS. 5 and 6, the pivot assembly 114 is
positioned to mimic a normal human ankle axis. FIG. 7 further
illustrates a schematic drawing indicating the correlation between
an ankle pivot point on a prosthetic foot unit 204 with the natural
human ankle joint of a foot. In particular, the prosthetic foot
unit 204 comprises a pivot assembly 214 that corresponds to an
ankle joint 240 of a human foot 242. For example, in one embodiment
of the invention, the pivot assembly 114 is located near the
mechanical ankle center of rotation of the prosthesis 100.
[0067] FIG. 8 illustrates a graph depicting the possible range of
ankle motion of an embodiment of the prosthesis 100 during one full
stride on a level surface. As shown, the x-axis of the graph
represents various points during one full stride of a user (i.e., 0
to 100 percent). The y-axis represents the ankle angle (.DELTA.) of
the prosthesis 100 relative to the ankle angle when the prosthesis
is in a neutral position. During one full stride, the ankle angle
(.DELTA.) varies from approximately 20 degrees plantarflexion
(i.e., neutral position angle+20 degrees) to approximately 10
degrees dorsiflexion (i.e., neutral position angle-10 degrees).
[0068] In embodiments as described above, no dampening is provided
when adjusting the angular range of motion. In another embodiment
of the invention, the prosthesis 100 is configured to provide
dampening or passive, soft resistance to changes in the angle
between the lower limb member 102 and the foot unit 104. An example
of a system for controlling such dampening is disclosed in U.S.
Pat. No. 6,443,993, which is hereby incorporated herein by
reference and is to be considered as a part of this
specification.
[0069] For example, when the user is in a standing position, the
actuator 116 may provide for increased resistance, or dampening, so
as to provide stability to the user. In one embodiment of the
invention, dampening of the prosthesis 100 may be provided by
hydraulic dampers. In other embodiments of the invention, other
components or devices that are known in the art may be used to
provide dampening for the prosthesis 100. In addition, in one
embodiment of the invention, the dampers may be dynamically
controlled, such as through an electronic control system, which is
discussed in more detail below. In yet other embodiments, the
dampers may be controlled through mechanical and/or fluid-type
structures.
[0070] It is also recognized that, although the above description
has been directed generally to prosthetic systems and devices, the
description may also apply to an embodiment of the invention having
an orthotic system or device. For example, in one embodiment of the
invention, an orthotic system may comprise at least one actuator
that actively controls the angle of an orthosis that is used with
an injured or debilitated ankle. In addition, the orthotic system
may, in addition to the electronic control of the orthotic system,
provide for the user's control or natural movement of the injured
ankle or leg.
[0071] In addition, the above-described systems may be implemented
in prosthetic or orthotic systems other than transtibial, or
below-the-knee, systems. For example, in one embodiment of the
invention, the prosthetic or orthotic system may be used in a
transfemoral, or above-the-knee, system, such as is disclosed in
U.S. Provisional Application No. 60/569,512, filed May 7, 2004, and
entitled "MAGNETORHEOLOGICALLY ACTUATED PROSTHETIC KNEE" and U.S.
Provisional Application No. 60/624,986, filed Nov. 3, 2004, and
entitled "MAGNETORHEOLOGICALLY ACTUATED PROSTHETIC KNEE", each of
which is hereby incorporated herein by reference in its entirety
and is to be considered as part of this specification. For example,
the prosthetic or orthotic system may include both a prosthetic or
orthotic ankle and/or a prosthetic or orthotic knee.
[0072] FIG. 9 illustrates a block diagram of one embodiment of a
system architecture of a control system 300 for an
ankle-motion-controlled foot. In one embodiment of the invention,
the control system 300 is usable by the lower limb prosthesis 100
depicted in FIGS. 1-6. In other embodiments of the invention the
control system 300 is usable by an orthotic system or a
rehabilitation system having an ankle-motion-controlled foot, or
other motion-controlled limb. In one embodiment, the control system
300 is based on a distributed processing system wherein the
different functions performed by the prosthetic or orthotic system,
such as sensing, data processing, and actuation, are performed or
controlled by multiple processors that communicate with each other.
With reference to FIG. 9, the control system 300 includes a sensor
module 302, an ankle device 304 (such as, for example, the
prosthesis 100 depicted in FIG. 1), a central processing unit
("CPU") 305, a memory 306, an interface module 308, a control drive
module 310, an actuator 316 and a power module 318.
[0073] In one embodiment, the control system 300 depicted in FIG. 9
processes data received from the sensing module 302 with the CPU
305. The CPU 305 communicates with the control drive module 310 to
control the operation of the actuator 316 so as to mimic natural
ankle movement by the ankle device 304. Furthermore, the control
system 300 may predict how the ankle device 304 may need to be
adjusted in order to accommodate movement by the user. The CPU 305
may also receive commands from a user and/or other device through
the interface module 308. The power module 318 provides power to
the other components of the control system 300. Each of these
components is described in more detail below.
[0074] In one embodiment, the sensor module 302 is used to measure
variables relating to the ankle device 304, such as the position
and/or the movement of the ankle device 304 throughout a gait
cycle. In such an embodiment the sensor module 320 is
advantageously located on the ankle device 304. For example, the
sensor module 302 may be located near a mechanical ankle center of
rotation of the ankle device 304, such as the pivot assembly 114 of
the prosthesis 100 depicted in FIG. 2. In another embodiment, the
sensor module 302 may be located on the user's natural limb that is
attached to, or associated with, the ankle device 304. In such an
embodiment, the sensors are used to capture information relating to
the movement of the natural limb on the user's ankle-device side to
adjust the ankle device 304.
[0075] In one embodiment, the sensor module 302 advantageously
includes a printed circuit board housing, multiple sensors, such as
accelerometers, which each measures an acceleration of the ankle
device 304 in a different axis. For example, the sensor module 302
may comprise three accelerometers that measure acceleration of the
ankle device 304 in three substantially, mutually perpendicular
axes. Sensors of the type suitable for the sensor module 302 are
available from, for example, Dynastream Innovations, Inc. (Alberta,
Canada).
[0076] In other embodiments, the sensor module 302 may include one
or more other types of sensors in combination with, or in place of,
accelerometers. For example, the sensor module 302 may include a
gyroscope configured to measure the angular speed of body segments
and/or the ankle device 304. In other embodiments, the sensor
module 302 includes a plantar pressure sensor configured to
measure, for example, the vertical plantar pressure of a specific
underfoot area. In yet other embodiments, the sensor module 302 may
include one or more of the following: kinematic sensors,
single-axis gyroscopes, single- or multi-axis accelerometers, load
sensors, flex sensors or myoelectric sensors that may be configured
to capture data from the user's natural limb. U.S. Pat. No.
5,955,667, U.S. Pat. No. 6,301,964, and U.S. Pat. No. 6,513,381,
also illustrate examples of sensors that may be used with
embodiments of the invention, which patents are herein incorporated
by reference in their entireties and are to be considered as part
of this specification.
[0077] Furthermore, the sensor module 302 may be used to capture
information relating to, for example, one or more of the following:
the position of the ankle device 304 with respect to the ground;
the inclination angle of the ankle device 304; the direction of
gravity with respect to the position of the ankle device 304;
information that relates to a stride of the user, such as when the
ankle device 304 contacts the ground (e.g., "heel strike"), is in
mid-stride, or leaves the ground (e.g., "toe-off"), the distance
from the ground of the prosthesis 100 at the peak of the swing
phase (i.e., the maximum height during the swing phase); the timing
of the peak of the swing phase; and the like.
[0078] In yet other embodiments, the sensor module 302 is
configured to detect gait patterns and/or events. For example, the
sensor module 302 may determine whether the user is in a
standing/stopped position, is walking on level ground, is ascending
and/or descending stairs or sloped surfaces, or the like. In other
embodiments, the sensor module 302 is configured to detect or
measure the heel height of the ankle device 304 and/or determine a
static shank angle in order to detect when the user is in a sitting
position.
[0079] As depicted in FIG. 9, in one embodiment of the invention,
the sensor module 302 is further configured to measure
environmental or terrain variables including one or more of the
following: the characteristics of the ground surface, the angle of
the ground surface, the air temperature and wind resistance. In one
embodiment, the measured temperature may be used to calibrate the
gain and/or bias of other sensors.
[0080] In other embodiments, the sensor module 302 captures
information about the movement and/or position of a user's natural
limb, such as a healthy leg. In such an embodiment, it may be
preferable that when operating on an incline or a decline, the
first step of the user be taken with the healthy leg. Such would
allow measurements taken from the natural movement of the healthy
leg prior to adjusting the ankle device 304. In one embodiment of
the invention, the control system 300 detects the gait of the user
and adjusts the ankle device 304 accordingly while the ankle device
304 is in a swing phase of the first step. In other embodiments of
the invention, there may be a latency period in which the control
system 300 requires one or two strides before being able to
accurately determine the gait of the user and to adjust the ankle
device 304 appropriately.
[0081] In one embodiment of the invention, the sensor module 302
has a default sampling rate of 100 hertz (Hz). In other
embodiments, the sampling rate may be higher or lower than 100 Hz
or may be adjustable by a user, or may be adjusted automatically by
software or parameter settings. In addition, the sensor module 302
may provide for synchronization between types of data being sensed
or include time stamping. The sensors may also be configured so as
to have an angular resolution of approximately 0.5 degrees,
allowing for fine adjustments of the ankle device 304.
[0082] In one embodiment, the sensor module 302 is configured to
power down into a "sleep" mode when sensing is not needed, such as
for example, when the user is relaxing while in a sitting or
reclining position. In such an embodiment, the sensor module 302
may awake from the sleep state upon movement of the sensor module
302 or upon input from the user. In one embodiment, the sensor
module 302 consumes approximately 30 milliamps (mA) when in an
"active" mode and approximately 0.1 mA when in a "sleep" mode.
[0083] FIG. 9 illustrates the sensor module 302 communicating with
the CPU 305. In one embodiment, the sensor module 302
advantageously provides measurement data to the CPU 305 and/or to
other components of the control system 300. In one embodiment, the
sensor module 302 is coupled to a transmitter, such as, for
example, a Bluetooth.RTM. transmitter, that transmits the
measurements to the CPU 305. In other embodiments, other types of
transmitters or wireless technology may be used, such as infrared,
WiFi.RTM., or radio frequency (RF) technology. In other
embodiments, wired technologies may be used to communicate with the
CPU 305.
[0084] In one embodiment, the sensor module 302 sends a data string
to the CPU 305 that comprises various types of information. For
example, the data string may comprise 160 bits and include the
following information:
[0085] [TS; AccX; AccY; AccZ; GyroX, GyroY, GyroZ, DegX, DegY, FS,
M]; [0086] wherein TS=Timestamp; AccX=linear acceleration of foot
along X axis; AccY=linear acceleration of foot along Y axis;
AccZ=linear acceleration of foot along Z axis; GyroX=angular
acceleration of foot along X axis; GyroY=angular acceleration of
foot along Y axis; GyroZ=angular acceleration of foot along Z axis;
DegX=foot inclination angle in coronal plane; DegY=foot inclination
angle in sagittal plane; FS=logic state of switches in the ankle
device 304; and M=orientation of the sensors. In other embodiments
of the invention, other lengths of data strings comprising more or
less information may be used.
[0087] The CPU 305 advantageously processes data received from
other components of the control system 300. In one embodiment of
the invention, the CPU 305 processes information relating to the
gait of the user, such as information received from the sensor
module 302, determines locomotion type (i.e., gait pattern), and/or
sends commands to the control drive module 310. For example, the
data captured by the sensor module 302 may be used to generate a
waveform that portrays information relating to the gait or movement
of the user. Subsequent changes to the waveform may be identified
by the CPU 305 to predict future movement of the user and to adjust
the ankle device 304 accordingly. In one embodiment of the
invention, the CPU 305 may detect gait patterns from as slow as 20
steps per minute to as high as 125 steps per minute. In other
embodiments of the invention, the CPU 305 may detect gait patterns
that are slower than 20 steps per minute or higher than 125 steps
per minute.
[0088] In one embodiment of the invention, the CPU 305 processes
data relating to state transitions according to the following table
(TABLE 1). In particular, TABLE 1 shows possible state transitions
usable with the control system 300. The first column of TABLE 1
lists possible initial states of the ankle device 304, and the
first row lists possible second states of the ankle device 304. The
body of TABLE 1 identifies the source of data used by the CPU 305
in controlling, or actively adjusting, the actuator 316 and the
ankle device 304 during the transition from a first state to a
second state; wherein "N" indicates that no additional data is
needed for the state transition; "L" indicates that the CPU 305
uses transition logic to determine the adjustments to the ankle
device 304 during the state transition; and "I" indicates the CPU
receives data from an interface (e.g., interface module 308,
external user interface, electronic interface or the like).
Transition logic usable with embodiments of the invention may be
developed by one with ordinary skill in the relevant art. Examples
of transition logic used in similar systems and methods to
embodiments of the present invention are disclosed in U.S.
Provisional Application No. 60/572,996, entitled "CONTROL SYSTEM
AND METHOD FOR A PROSTHETIC KNEE," filed May 19, 2004, which is
hereby incorporated herein by reference and is to be considered as
a part of this specification.
TABLE-US-00001 TABLE 1 TRANSITIONS FROM STATE TO STATE OFF
HEEL_HEIGHT_CAL SENSOR_CAL NEUTRAL WALK OFF N I I I N
HEEL_HEIGHT_CAL L N N L N SENSOR_CAL L N N L N NEUTRAL I I I N L
WALK I N N L N STAIRS_UP I N N L L STAIRS_DOWN I N N L L RELAX I N
N L N PANTS I N N I N TRANSITIONS FROM STATE TO STATE STAIRS_UP
STAIRS_DOWN RELAX PANTS OFF N N I I HEEL_HEIGHT_CAL N N N N
SENSOR_CAL N N N N NEUTRAL L L L I WALK L L N N STAIRS_UP N L N N
STAIRS_DOWN L N N N RELAX N N N I PANTS N N N N
[0089] In one embodiment, the above described states in TABLE 1 are
predefined states of the ankle device 304. For example, the "OFF"
state may indicate that the functions of the ankle device 304 and
the actuator 316 are in an off or suspend mode. The
"HEEL_HEIGHT_CAL" state relates to the measuring of a heel height
from a static sensor angle such as, for example, when the ankle
device 304 is not in motion. The "SENSOR_CAL" state relates to
surface angle calibration when the user is walking on a level
surface. The "NEUTRAL" state relates to when the ankle device 304
is locked in a substantially fixed position. The "WALK" state
relates to when the user is walking, such as on a level or sloped
surface. "The "STAIRS_UP" and "STAIRS_DOWN" states relate to when
the user is walking, respectively, up and down stairs. The "RELAX"
state relates to when the user is in a relaxed position. For
example, in one embodiment, the "RELAX" state relates to when a
user is in a sitting position with the limb having the ankle device
304 crossed over the other limb. In such an embodiment, the control
system 300 may cause the ankle device 304 to move into a maximum
plantarflexion position to mimic, for example, the natural position
and/or look of a healthy foot. The "PANTS" state relates to when a
user is putting on pants, trousers, shorts or the like. In such a
state, the control system 300 may, in one embodiment, cause the
ankle device 304 to move into a maximum plantarflexion position to
facilitate putting the clothing on over the ankle device 304.
[0090] In other embodiments of the invention, other states are
usable with the ankle device 304 in place of, or in combination
with, the states identified in TABLE 1. For example, states may be
defined that correspond to lying down, cycling, climbing a ladder
or the like. Furthermore, in controlling the state transitions, the
CPU 305 and/or control system 300 may process or derive data from
sources other than those listed in TABLE 1.
[0091] In other embodiments, the CPU 305 may perform a variety of
other functions. For example, the CPU 305 may use information
received from the sensor module 302 to detect stumbling by the
user. The CPU 305 may function as a manager of communication
between the components of the control system 300. For example, the
CPU 305 may act as the master device for a communication bus
between multiple components of the control system 300. As
illustrated, in one embodiment, the CPU 305 communicates with the
power module 318. For example, the CPU 305 may provide power
distribution and/or conversion to the other components of the
control system 300 and may also monitor battery power or battery
life. In addition, the CPU 305 may function so as to temporarily
suspend or decrease power to the control system 300 when a user is
in a sitting or a standing position. Such control provides for
energy conservation during periods of decreased use. The CPU 305
may also process error handling, such as when communication fails
between components, an unrecognized signal or waveform is received
from the sensor module 302, or when the feedback from the control
drive module 310 or the ankle device 304 causes an error or appears
corrupt.
[0092] In yet other embodiments of the invention, the CPU 305 uses
or computes a security factor when analyzing information from the
sensor module 302 and/or sending commands to the control drive
module 310. For example, the security factor may include a range of
values, wherein a higher value indicates a higher degree of
certainty associated with a determined locomotion type of the user,
and a lower security factor indicates a lower degree of certainty
as to the locomotion type of the user. In one embodiment of the
invention, adjustments are not made to the ankle device 304 unless
the locomotion type of the user is recognized with a security
factor above a predetermined threshold value.
[0093] In one embodiment, the CPU 305 includes modules that
comprise logic embodied in hardware or firmware, or that comprise a
collection of software instructions written in a programming
language, such as, for example C++. A software module may be
compiled and linked into an executable program, installed in a
dynamic link library, or may be written in an interpretive language
such as BASIC. It will be appreciated that software modules may be
callable from other modules or from themselves, and/or may be
invoked in response to detected events or interrupts. Software
instructions may be embedded in firmware, such as an EPROM or
EEPROM. It will be further appreciated that hardware modules may be
comprised of connected logic units, such as gates and flip-flops,
and/or may be comprised of programmable units, such as programmable
gate arrays or processors.
[0094] FIG. 9 further depicts CPU 305 including a memory 306 for
storing instructions and/or data. For example, the memory 306 may
store one or more of the following types of data or instructions:
an error log for the other components of the control system 300;
information regarding gait patterns or curves; information
regarding past activity of the user (e.g., number of steps);
control parameters and set points; information regarding software
debugging or upgrading; preprogrammed algorithms for basic
movements of the prosthetic or orthotic system; calibration values
and parameters relating to the sensor module 302 or other
components; instructions downloaded from an external device;
combinations of the same or the like.
[0095] The memory 306 may comprise any buffer, computing device, or
system capable of storing computer instructions and/or data for
access by another computing device or a computer processor. In one
embodiment, the memory 306 is a cache that is part of the CPU 305.
In other embodiments of the invention, the memory 306 is separate
from the CPU 305. In other embodiments of the invention, the memory
306 comprises random access memory (RAM) or may comprise other
integrated and accessible memory devices, such as, for example,
read-only memory (ROM), programmable ROM (PROM), and electrically
erasable programmable ROM (EEPROM). In another embodiment, the
memory 306 comprises a removable memory, such as a memory card, a
removable drive, or the like.
[0096] In one embodiment, the CPU 305 may also be configured to
receive through the interface module 308 user- or activity-specific
instructions from a user or from an external device. The CPU 305
may also receive updates to already existing instructions.
Furthermore, the CPU 305 may communicate with a personal computer,
a personal digital assistant, or the like so as to download or
receive operating instructions. Activity-specific instructions may
include, for example, data relating to cycling, driving, ascending
or descending a ladder, adjustments from walking in snow or sand,
or the like.
[0097] In one embodiment, the interface module 308 comprises an
interface that the user accesses so as to control or manage
portions or functions of the prosthetic or orthotic system. In one
embodiment, the interface module 308 is a flexible keypad having
multiple buttons and/or multiple light emitting diodes (LEDs)
usable to receive information from and/or convey information to a
user. For example, the LEDs may indicate the status of a battery or
may convey a confirmation signal to a user. The interface module
308 may be advantageously located on the ankle device 304.
Furthermore, the interface module 308 may comprise a USB connector
usable for communication to an external computing device, such as a
personal computer.
[0098] In a further embodiment, the interface module 308 comprises
an on/off switch. In another embodiment, the interface module 308
may receive input regarding the user-controlled heel height or a
forced relaxed mode of the prosthetic or orthotic system. In other
embodiments, the user may adjust the type of response desired of
the prosthesis or enable/disable particular functions of the ankle
device 304. The input from the user may be entered directly via the
interface module 308, such as through actuating a button, or user
input may be received via a remote control.
[0099] The interface module 308 may comprise a touch screen,
buttons, switches, a vibrator, an alarm, or other input-receiving
or output structures or devices that allow a user to send
instructions to or receive information from the control system 300.
In another embodiment of the invention, the interface module 308
comprises an additional structure, such as a plug, for charging a
battery powering the control system 300, such as at home or in a
vehicle. In other embodiments of the invention, the interface
module 308 may also communicate directly or indirectly with
components of the control system 300 other than the CPU 305.
[0100] The control drive module 310 is used to translate high-level
plans or instructions received from the CPU 305 into low-level
control signals to be sent to the actuator 316. In one embodiment,
the control drive module 310 comprises a printed circuit board that
implements control algorithms and tasks related to the management
of the actuator 316. In addition, the control drive module 310 may
be used to implement a hardware abstraction layer that translates
the decision processes of the CPU 305 to the actual hardware
definition of the actuator 316. In another embodiment of the
invention, the control drive module 310 may be used to provide
feedback to the CPU 305 regarding the position or movement of the
actuator 316 or ankle device 304. The control drive module 310 may
also be used to adjust the actuator 316 to a new "neutral" setting
upon detection by the CPU 305 that the user is traveling on an
angled surface.
[0101] In one embodiment of the invention, the control drive module
310 is located within the ankle device 304. In other embodiments,
the control drive module 310 may be located on the outside of the
ankle device 304, such as on a socket, or remote to the ankle
device 304.
[0102] The actuator 316 provides for the controlled movement of the
ankle device 304. In one embodiment, the actuator 316 functions
similarly to the actuator 116 described with respect to FIGS. 1-6,
which actuator 116 controls the ankle motion of the prosthesis 100.
In other embodiments of the invention, the actuator 316 may be
configured to control the motion of an orthotic device, such as a
brace or other type of support structure.
[0103] The ankle device 304 comprises any structural device that is
used to mimic the motion of a joint, such as an ankle, and that is
controlled, at least in part, by the actuator 316. In particular,
the ankle device 304 may comprise a prosthetic device or an
orthotic device.
[0104] The power module 318 includes one or more sources and/or
connectors usable to power the control system 300. In one
embodiment, the power module 318 is advantageously portable, and
may include, for example, a rechargeable battery, as discussed
previously. As illustrated in FIG. 9, the power module 318
communicates with the control drive module 310 and the CPU 305. In
other embodiments, the power module 318 communicates with other
control system 300 components instead of, or in combination with,
the control drive module 310 and the CPU 305. For example, in one
embodiment, the power module 318 communicates directly with the
sensor module 302. Furthermore, the power module 318 may
communicate with the interface module 308 such that a user is
capable of directly controlling the power supplied to one or more
components of the control system 300.
[0105] The components of the control system 300 may communicate
with each other through various communication links. FIG. 9 depicts
two types of links: primary communication links, which are depicted
as solid lines between the components, and secondary communication
links, which are depicted as dashed lines. In one embodiment,
primary communication links operate on an established protocol. For
example, the primary communication links may run between physical
components of the control system 300. Secondary communication
links, on the other hand, may operate on a different protocol or
level than the primary communication links. For example, if a
conflict exists between a primary communication link and a
secondary communication link, the data from the primary
communication link will override the data from the secondary
communication link. The secondary communication links are shown in
FIG. 9 as being communication channels between the control system
300 and the environment. In other embodiments of the invention, the
modules may communicate with each other and/or the environment
through other types of communication links or methods. For example,
all communication links may operate with the same protocol or on
the same level of hierarchy.
[0106] It is also contemplated that the components of the control
system 300 may be integrated in different forms. For example, the
components can be separated into several subcomponents or can be
separated into more devices that reside at different locations and
that communicate with each other, such as through a wired or
wireless network. For example, in one embodiment, the modules may
communicate through RS232 or serial peripheral interface (SPI)
channels. Multiple components may also be combined into a single
component. It is also contemplated that the components described
herein may be integrated into a fewer number of modules. One module
may also be separated into multiple modules.
[0107] Although disclosed with reference to particular embodiments,
the control system 300 may include more or fewer components than
described above. For example, the control system 300 may further
include an actuator potentiometer usable to control, or fine-tune,
the position of the actuator 316. The user may also use the
actuator potentiometer to adjust the heel height of the ankle
device 304. In one embodiment, the actuator potentiometer
communicates with the CPU 305. In other embodiments, the control
system 300 may include a vibrator, a DC jack, fuses, combinations
of the same, or the like.
[0108] Examples of similar or other control systems and other
related structures and methods are disclosed in U.S. patent
application Ser. No. 10/463,495, filed Jun. 17, 2003, entitled
"ACTUATED LEG PROSTHESIS FOR ABOVE-KNEE AMPUTEES," now published as
U.S. Publication No. 2004/0111163; U.S. patent application Ser. No.
10/600,725, filed Jun. 20, 2003, entitled "CONTROL SYSTEM AND
METHOD FOR CONTROLLING AN ACTUATED PROSTHESIS," now published as
U.S. Publication No. 2004/0049290; U.S. patent application Ser. No.
10/627,503, filed Jul. 25, 2003, entitled "POSITIONING OF LOWER
EXTREMITIES ARTIFICIAL PROPRIOCEPTORS," now published as U.S.
[0109] Publication No. 2004/0088057; and U.S. patent application
Ser. No. 10/721,764, filed Nov. 25, 2003, entitled "ACTUATED
PROSTHESIS FOR AMPUTEES," now published as U.S. Publication No.
2004/0181289; each which is herein incorporated by reference in its
entirety and is to be considered as part of this specification. In
addition, other types of control systems that may be used in
embodiments of the present invention are disclosed in U.S.
Provisional Application No. 60/551,717, entitled "CONTROL SYSTEM
FOR PROSTHETIC KNEE," filed Mar. 10, 2004; U.S. Provisional
Application No. 60/569,511, entitled "CONTROL SYSTEM AND METHOD FOR
A PROSTHETIC KNEE," filed May 7, 2004; and U.S. Provisional
Application No. 60/572,996, entitled "CONTROL SYSTEM AND METHOD FOR
A PROSTHETIC KNEE," filed May 19, 2004, which are herein
incorporated by reference in their entireties to be considered as
part as this specification.
[0110] FIG. 10 is a table that depicts possible control signals
that may be involved in adjusting the ankle angle of a prosthetic
or orthotic device when a user is transitioning between different
states, or types of locomotion, according to one embodiment of the
invention. In particular, the states listed in a column 402
identify a first state of the user, and the states listed in a row
404 identify a second state of the user, or the state to which the
user is transitioning. The remainder of the table identifies
possible actions that may be taken by the prosthetic or orthotic
device with respect to the ankle angle. "User set point" is the
neutral, or default, value that may be set during shoe heel height
adjustment. The angles specified are examples of changes to the
ankle angle of the prosthetic or orthotic device. For example, when
a user is transitioning from a "stance" state to an "ascending
stairs" state, the ankle angle may be adjusted to the angle of the
stairs, such as for example, -10 degrees (or 10 degrees
dorsiflexion). Ankle angles given in the "Incline (up)" and
"Decline" columns reflect threshold levels of ankle angle
adjustment depending on the angle of the incline.
[0111] The following table (TABLE 2) illustrates possible ankle
motion strategies for one embodiment of the invention. The first
column of TABLE 2 lists different types of locomotion types or gait
patterns that may be frequently detected. The second column of
TABLE 2 identifies examples of ankle angle adjustment of the
prosthetic or orthotic device during the swing phase of each of the
identified locomotion types.
TABLE-US-00002 TABLE 2 Locomotion Type/Gait Pattern Ankle Motion
During Swing Phase of Ankle Device Level Ground Toe clearance
during swing Walking Ascending Stairs Ankle adjusts to dorsiflexion
(e.g., 7.5.degree.) Descending Stairs Ankle adjusts to dorsiflexion
(e.g., 5.degree.) Incline (up) Ankle adjust to dorsiflexion: a) Two
incline angle threshold levels (x.degree., y.degree.) b) Stepwise
(2 steps) angle adjustment (z.degree., w.degree.) Example: If
incline angle > x.degree., ankle will adjust to -z.degree.; if
incline angle > y.degree., ankle will adjust to -w.degree.,
wherein x = 2.5.degree. and y = 5.degree.. Decline Ankle adjusts to
plantarflexion: a) Two decline angle threshold levels (x.degree.,
y.degree.) b) Stepwise (2 steps) angle adjustment (z.degree.,
w.degree.) Example: If decline angle > x.degree., ankle will
adjust to z.degree.; if decline angle > y.degree., ankle will
adjust to w.degree., wherein x = 2.5.degree. and y = 5.degree..
Sitting/Relaxed Set Heel Height Adjust Heel Stepless heel height
adjustment up to 20.degree. Height plantarflexion
[0112] FIG. 11 depicts a graph that illustrates the interaction and
relationship between the control of a prosthetic or orthotic leg
and the measurements taken from a healthy, sound leg. In
particular, FIG. 11 depicts the movement of a prosthetic or
orthotic leg and a healthy leg during one full stride of a user.
For example, during approximately the first 60% of the stride, the
graph shows the prosthetic or orthotic leg as being in a "stance"
position or being planted on a surface, such as the ground. In one
embodiment, during the beginning portion of the stance phase the
ankle angle of the prosthetic or orthotic leg may decrease
(dorsiflexion). Toward the end of the stance phase the ankle angle
of the prosthetic or orthotic leg may then increase
(plantarflexion) to facilitate natural stride movements. In other
embodiments of the invention, the ankle angle of the prosthetic or
orthotic leg is not actively adjusted during the stance phase.
During a portion of this same period, up to approximately point
40%, the healthy leg may be in a swinging position, wherein the
healthy leg is not in contact with the ground. Between the points
of approximately 40% and 60%, both legs are in contact with the
ground.
[0113] From approximately point 60% to 100% (the end of the
stride), the prosthetic or orthotic leg is in a swinging position,
and the healthy leg is in contact with the ground. The graph in
FIG. 11 shows that the ankle angle of the prosthetic or orthotic
leg is adjusted during the swing phase. This angle adjustment may
be based on previous measurements of the healthy leg during the
swing phase of the healthy leg. In one embodiment, during the
beginning portion of the swing phase of the prosthetic or orthotic
leg, the ankle angle of the prosthetic or orthotic leg may
decrease. This allows, for example, a toe portion of the prosthetic
or orthotic leg to clear stairs. Toward the latter portion of the
swing phase of the prosthetic or orthotic leg, the ankle angle of
the prosthetic or orthotic leg may then increase before contacting
the ground. In other embodiments, the angle adjustment is based on
readings taken by sensors on the prosthetic side.
[0114] It is to be understood that FIG. 11 is illustrative of the
functioning of one embodiment of the invention under certain
conditions. Other embodiments or circumstances may require a longer
or shorter stance or swing phase and require other adjustments to
the angle of the ankle portion of the prosthetic leg.
[0115] While certain embodiments of the inventions have been
described, these embodiments have been presented by way of example
only, and are not intended to limit the scope of the inventions.
Indeed, the novel methods and systems described herein may be
embodied in a variety of other forms. For example, the foregoing
may be applied to the motion-control of joints other than the
ankle, such as a knee or a shoulder. Furthermore, various
omissions, substitutions and changes in the form of the methods and
systems described herein may be made without departing from the
spirit of the inventions. The accompanying claims and their
equivalents are intended to cover such forms or modifications as
would fall within the scope and spirit of the inventions.
* * * * *