U.S. patent application number 14/670209 was filed with the patent office on 2015-09-24 for control systems and methods for prosthetic or orthotic devices.
The applicant listed for this patent is Ossur hf.. Invention is credited to Arinbjorn V. Clausen.
Application Number | 20150265426 14/670209 |
Document ID | / |
Family ID | 43050450 |
Filed Date | 2015-09-24 |
United States Patent
Application |
20150265426 |
Kind Code |
A1 |
Clausen; Arinbjorn V. |
September 24, 2015 |
CONTROL SYSTEMS AND METHODS FOR PROSTHETIC OR ORTHOTIC DEVICES
Abstract
Geomagnetic methods and systems are used for monitoring the
directionality of a prosthetic or orthotic device. Certain methods
may include measuring multiple data points over a particular time
interval to identify orientation information with respect to a
prosthetic or orthotic device and/or used in the real-time control
of the prosthetic or orthotic device. In certain examples, multiple
points may be further compared with stored orientation data
associated with predefined unsafe gait patterns. Control
instructions and/or alerts based on the geomagnetic measurements
can then be generated for the prosthetic or orthotic device, such
as if the orientation data information matches one of the
predefined unsafe gait patterns.
Inventors: |
Clausen; Arinbjorn V.;
(Reykjavik, IS) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ossur hf. |
Reykjavik |
|
IS |
|
|
Family ID: |
43050450 |
Appl. No.: |
14/670209 |
Filed: |
March 26, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12773788 |
May 4, 2010 |
9017418 |
|
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14670209 |
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61175713 |
May 5, 2009 |
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Current U.S.
Class: |
623/39 ; 602/5;
623/47; 700/279 |
Current CPC
Class: |
A61F 2002/769 20130101;
A61F 2002/6827 20130101; A61F 2002/7625 20130101; G05B 15/02
20130101; A61F 2002/704 20130101; A61F 2002/7635 20130101; A61F
2/605 20130101; A61F 2002/6863 20130101; A61F 2/6607 20130101; A61F
2/60 20130101; A61F 2/70 20130101; A61F 2/68 20130101; A61F
2250/008 20130101; A61F 2002/764 20130101; A61F 2002/689 20130101;
A61F 2/64 20130101; A61F 5/0102 20130101; A61F 2002/763
20130101 |
International
Class: |
A61F 2/68 20060101
A61F002/68; G05B 15/02 20060101 G05B015/02; A61F 5/01 20060101
A61F005/01; A61F 2/64 20060101 A61F002/64; A61F 2/66 20060101
A61F002/66 |
Claims
1-20. (canceled)
21. A method for controlling an adjustable prosthetic or orthotic
device, the method comprising: measuring with a geo-magnetic sensor
a plurality of data points over a time interval, wherein the
plurality of data points provides orientation data information of a
prosthetic or orthotic device with respect to the earth's magnetic
field; processing the plurality of data points over the time
interval by comparing the orientation data information with
predefined gait patterns related to a change in geomagnetic
direction; and outputting control instructions to the prosthetic or
orthotic device when the orientation data information indicates a
turn greater than 20 degrees while walking, the control
instructions comprising at least one of an alert command and an
instruction to control or restrict movement of the prosthetic or
orthotic device.
22. The method of claim 21, wherein the orientation data
information comprises at least a first angle, a second angle, and a
third angle and wherein the first, second, and third angle
comprises a roll, inclination, and azimuth angle, respectively.
23. The method of claim 22, wherein the geo-magnetic sensor
measures the plurality of data points with an accuracy of between
about 0.01 and about 1.0 degrees for the first and second angles
and between about 1.0 and about 2.0 for the third angle.
24. The method of claim 22, wherein the geo-magnetic sensor
recognizes any directional change greater than about 20 degrees for
the first, second, and third angles.
25. The method of claim 21, further comprising the step of
outputting control instructions to the prosthetic or orthotic
device when the orientation data information indicates at least one
of walking on a slope and walking on stairs such that the
prosthetic or orthotic device operates according to said at least
one of walking on a slope or walking on stairs.
26. The method of claim 21, further comprising the step of
outputting control instructions to the prosthetic or orthotic
device when the orientation data information indicates a u-turn
after walking on stairs such that the prosthetic or orthotic device
operates according to level ground walking.
27. The method of claim 21, wherein the turn greater than 20
degrees is about the same spot.
28. A method for controlling an adjustable prosthetic or orthotic
device, the method comprising: measuring with a geo-magnetic sensor
a plurality of data points over a time interval, wherein the
plurality of data points provides orientation data information of a
prosthetic or orthotic device with respect to the earth's magnetic
field; processing the plurality of data points over the time
interval by comparing the orientation data information with
predefined gait patterns corresponding to at least one of walking
on a slope and walking on stairs; and outputting control
instructions to the prosthetic or orthotic device when the
orientation data information matches at least one of walking on a
slope and walking on stairs such that the prosthetic or orthotic
device operates according to said at least one of walking on a
slope or walking on stairs.
29. The method of claim 28, wherein the orientation data
information comprises at least a first angle, a second angle, and a
third angle and wherein the first, second, and third angle
comprises a roll, inclination, and azimuth angle, respectively.
30. The method of claim 29, wherein the geo-magnetic sensor
measures the plurality of data points with an accuracy of between
about 0.01 and about 1.0 degrees for the first and second angles
and between about 1.0 and about 2.0 for the third angle.
31. The method of claim 29, wherein the geo-magnetic sensor
recognizes any directional change greater than about 20 degrees for
the first, second, and third angles.
32. The method of claim 28, further comprising issuing an alert if
the orientation data information matches one of the predefined gait
patterns.
33. The method of claim 32, further comprising the steps of:
processing the plurality of data points over the time interval by
comparing the orientation data information with predefined gait
patterns corresponding with a u-turn; and outputting control
instructions to the prosthetic or orthotic device when the
orientation data information matches a u-turn after walking on
stairs such that the prosthetic or orthotic device operates
according to level-ground.
34. The method of claim 28, further comprising actuating the device
in response to the control instructions.
35. A prosthetic or orthotic device capable of monitoring
directionality and providing feedback control, comprising: at least
one geo-magnetic sensor disposed on an adjustable prosthetic or
orthotic device, wherein the at least one geo-magnetic sensor is
configured to monitor the geomagnetic directionality of the device
and provide geomagnetic directionality data; and a processor,
wherein the processor is configured to process the geomagnetic
directionality data to recognize at least one of walking on stairs
and walking on a slope and output a command based at least in part
on the geomagnetic directionality data, wherein the command
comprises an instruction to control the device for said at least
one of walking on stairs and walking on a slope.
36. The device of claim 35, wherein the processor is further
configured to process the geomagnetic directionality data to
recognize an unsafe gait pattern and to output at least one of an
alert command and an instruction to control or restrict movement of
the device when the unsafe gait pattern is recognized.
37. The device of claim 36, wherein the processor is configured to
output an alert command, the alert command comprising instructing a
warning system to output at least one of an auditory signal, a
tactile signal, and a locking mechanism based at least in part on
the directionality data.
38. The device of claim 35, wherein the device comprises a
prosthetic knee device.
39. The device of claim 35, wherein the device comprises a
prosthetic ankle device.
40. The device of claim 35, wherein the device comprises an
orthotic device.
41. The device of claim 35, wherein the processor is further
configured to process the geomagnetic directionality data to
recognize a u-turn after walking on a stairs and output a command
based at least in part on the recognized u-turn after walking on
stairs to control the device for level-ground walking.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priority benefit as a
continuation under 35 U.S.C. .sctn.120 to U.S. patent application
Ser. No. 12/773,788 (filed 4 May 2010), which claims the benefit of
U.S. Provisional Application No. 61/175,713, filed May 5, 2009, the
entirety of which is hereby incorporated by reference.
BACKGROUND
[0002] 1. Field of the Invention
[0003] Embodiments of this invention relate to controlling
prosthetic or orthotic devices and, in particular, to geomagnetic
sensing systems and methods for controlling such devices.
[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] While the technology for orthotic and prosthetic devices has
advanced to include basic sensor systems capable of providing some
degree of feedback control, these sensors have mainly included
proximity sensors, load sensors, accelerometers, tactile sensors,
pressure sensors, and others. Oftentimes, these sensors are not
capable of providing the prosthetic or orthotic system with the
information necessary to identify a sudden change in direction and,
in turn, the instructions necessary for dynamically adjusting to
the changing environment. Thus, prosthetic and orthotic users can
still experience instability in basic movements.
[0008] In certain embodiments of the invention, control systems and
methods for motion-controlled prosthetic or orthotic devices are
provided. These systems and methods include utilizing a sensor
system to measure directionality and/or movement of an
actively-adjustable prosthetic or orthotic system. In certain
embodiments, the sensor information is then compared with defined
gait patterns. If the sensor information corresponds to known
unsafe gait patterns, the prosthetic or orthotic system may issue a
warning and/or take other corrective action.
[0009] In one embodiment, a method for controlling an adjustable
prosthetic or orthotic device is included. The method comprises
measuring with a geo-magnetic sensor a plurality of data points
over a time interval. The plurality of data points provides
orientation data information of a prosthetic or orthotic device
with respect to the earth's magnetic field. The plurality of data
points are processed over the time interval by comparing the
orientation data information with predefined unsafe gait patterns.
Control instructions are outputted to the prosthetic or orthotic
device when the orientation data information matches one of the
predefined unsafe gait patterns.
[0010] In another embodiment, a motion-controlled prosthetic or
orthotic device is included. The device comprises a first upper
member and a second lower member moveable relative to the first
upper member at a natural human joint location. The first upper and
second lower members are articulated about the joint location with
respect to each other. At least one geo-magnetic sensor is disposed
on the motion-controlled prosthetic or orthotic device. The at
least one geo-magnetic sensor is configured to monitor the
directionality of the prosthetic or orthotic device with respect to
the earth's magnetic field and to provide directionality data. A
processor processes the directionality data and outputs a command
based at least in part on the directionality data. The command
comprises at least one of an alert command or an instruction to
control or restrict movement of the prosthetic or orthotic
device.
[0011] In another embodiment, a prosthetic or orthotic device
capable of monitoring directionality and providing feedback control
is included. The device comprises at least one geo-magnetic sensor
disposed on an adjustable prosthetic or orthotic device. The at
least one geo-magnetic sensor is configured to monitor the
directionality of the device and provide directionality data. The
device also comprises a processor, which processes the
directionality data and outputs a command based at least in part on
the directionality data. The command comprises at least one of an
alert command and an instruction to control or restrict movement of
the device.
[0012] For purposes of summarizing the disclosure, certain aspects,
advantages and novel features of the inventions 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
[0013] These and other features, aspects and advantages of the
present disclosure will now be described in connection with
non-exclusive embodiments, in reference to the accompanying
drawings. The illustrated embodiments, however, are merely examples
and are not intended to limit the invention. The following are
brief descriptions of the drawings, which may not be drawn to
scale.
[0014] In addition, methods and functions described herein are not
limited to any particular sequence, and the blocks or states
relating thereto can be performed in other sequences that are
appropriate. For example, described blocks or states may be
performed in an order other than that specifically disclosed, or
multiple blocks or states may be combined in a single block or
state.
[0015] FIG. 1A illustrates a block diagram of a geo-magnetic
sensing system for a prosthetic or orthotic device according to
certain embodiments of the invention.
[0016] FIG. 1B illustrates a decision tree for a geo-magnetic
sensing system on a prosthetic or orthotic device according to one
embodiment.
[0017] FIGS. 2A and 2B illustrate representative geo-magnetic
signal plots of a prosthetic user making a 180 degree rotation when
walking and rotating around the same location.
[0018] FIG. 3 illustrates a schematic illustration of a lower limb
prosthetic assembly according to one embodiment.
[0019] FIG. 4 illustrates a prosthetic knee device suitable for use
with a geo-magnetic sensor according to one embodiment.
[0020] FIG. 5 illustrates an orthotic device suitable for use with
a geo-magnetic sensor according to one embodiment.
[0021] FIG. 6 illustrates a block diagram identifying
instrumentation applied to an orthotic device according to one
embodiment.
[0022] FIG. 7 illustrates a block diagram of an ambulatory control
unit for an orthotic device according to one embodiment.
[0023] FIG. 8 illustrates another orthotic device suitable for use
with a geo-magnetic sensor according to one embodiment.
[0024] FIG. 9 illustrates another perspective of the orthotic
device coupled to a geo-magnetic sensor of FIG. 8.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] Some preferred embodiments of the invention described herein
relate generally to prosthetic and orthotic systems. 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.
[0026] The features of the systems and methods 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 disclosure.
[0027] 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.
[0028] 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.
[0029] 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.
[0030] The term "knee device" as used herein is a broad term and is
used in its ordinary sense and relates to any prosthetic, orthotic
or knee-assisting device.
[0031] The term "roll" as used herein is a broad term and is used
in its ordinary sense and relates to any turn or revolution about
one or more real and/or imaginary axes.
[0032] The term "inclination" as used herein is a broad term and is
used in its ordinary sense and relates to any angle between a
reference plane and another plane or axis of direction.
[0033] The term "azimuth" as used herein is a broad term and is
used in its ordinary sense and relates to any angle from a
reference vector in a reference plane to a second vector in the
same plane, pointing toward (but not necessarily meeting) something
of interest.
[0034] Certain embodiments of the invention include a prosthetic or
orthotic device coupled to a geo-magnetic sensor capable of
measuring the orientation and/or movement of the device (roll,
inclination, and azimuth angles) with respect to a magnetic field.
Such embodiments can address disadvantageous of certain
conventional prosthetic or orthotic devices that have difficulty in
locating a center of gravity and/or registering absolute and
relative directions and sudden changes in direction when first
turned on and during use. While a typical prosthetic or orthotic
device is still able to operate without this information, this may
result in the user having less control and more awkward
movements.
[0035] In certain embodiments, a prosthetic device that is able to
measure the directional orientation and changes about an axis in
the rotational orientation of the device in real time improves gait
recognition and allows the user to have a quicker reaction time
because the prosthetic device can quickly determine whether and how
to shift its weight. Moreover, in certain embodiments, a prosthetic
or orthotic device that can sense direction, such as for example,
north, south, east, and west, can more quickly determine future
steps and/or other movement and provide more stability in turning,
for example in making a 180 degree turn or rotating around a
particular point. In certain embodiments, the prosthetic device
recognizes any directional change greater than 20 degrees in order
to establish safer terrain sensation and response. In addition, the
increase in information related to directionality can provide the
extra benefit of training the user in how to make healthy
movements. For example, if an orthotic user should not make certain
movements (e.g., if such these movements may increase the chance of
further injury), an alarm may sound to warn the user to substitute
the detrimental movement with a healthier one.
[0036] Embodiments of the invention advantageously utilize
geo-magnetic sensors to improve functionality and/or increase
safety on prosthetic and/or orthotic devices. One example of a
geo-magnetic sensor is a flux gate magnetometer. Examples of
geo-magnetic sensors may include products made by Alps Electric or
Yamaha Corporation. These sensors can be coupled with other types
of sensors, such as for example accelerometers or gyroscopes, or
with processors or controllers.
[0037] In certain embodiments, the geo-magnetic sensors are
designed to measure the orientation (e.g., roll, inclination,
and/or azimuth angles) of the prosthetic or orthotic device, based
on movement with respect to the earth's magnetic field. For
example, in certain embodiments, such measurements can be made with
an accuracy of between about 0.01.degree. and about 1.0.degree. for
the roll and inclination angles, between about 1.0.degree. and
about 2.0.degree. for the azimuth angle, and/or with an angular
resolution of about 0.1 .degree..
[0038] In certain embodiments, the geo-magnetic sensor may be used
for measuring gravitational forces as they relate to the operation
of prosthetic and/or orthotic devices. In certain embodiments, the
accuracy of such measurements may be between about 8.0 mg and about
9.0 mg and the resolution can be greater than about 1 mg.
[0039] In other embodiments, the geo-magnetic sensor may be used
for measuring a magnetic field, such as a geomagnetic field. For
example, in certain embodiments, an accuracy of such measurement
may be between about 0.01 .mu.T and about 0.2 .mu.T with a
resolution of between about 0.001 .mu.T and about 0.01 .mu.T. In
certain embodiments, the geo-magnetic sensors operate by supplying
data upon request by a processor and/or other control device
associated with the prosthetic or orthotic device. In other
embodiments, the geo-magnetic sensors operate by supplying data
continuously.
[0040] For example, in certain embodiments, the geo-magnetic
sensors may supply data in orientation format (e.g., roll,
inclination, and azimuth) and/or in position format (x, y, z). In
certain embodiments, the geo-magnetic sensors may range from about
0.5 mm to about 75 mm in length, width, and height and may vary in
shape. In certain embodiments, the geo-magnetic sensor can operate
at a temperature range of between about -10 and 50.degree. C.
[0041] FIG. 1A illustrates a block diagram of a geo-magnetic
sensing system for a motion-controlled prosthetic or orthotic
device according to certain embodiments of the invention. As shown,
a sensor system 10 receives input regarding the user's change in
orientation/direction and sends the information 25 to a prosthetic
or orthotic device 50. The prosthetic or orthotic device 50 can
then process the sensory information 25 and output feedback control
information 75, which may adjust the movements of the prosthetic or
orthotic device 50.
[0042] FIG. 1B further illustrates a decision tree for a
geo-magnetic sensing system on a prosthetic or orthotic device
according to one embodiment. As shown, when the geo-magnetic sensor
is integrated with a prosthetic or orthotic device, the sensor can
operate to provide feedback information to the device. In certain
embodiments, the geo-magnetic sensor obtains sensor values 110,
which can include the orientation (i.e., roll, inclination, and
azimuth angles) or the position data (x, y, and z). In one
embodiment, once the geo-magnetic sensor has collected information
related to the sensor values, a processing unit of the prosthetic
or orthotic device may estimate the type of terrain 120 the device
may encounter.
[0043] The processing unit, in certain embodiments, generates an
output of "level ground," or "stairs," or "slope" for a prosthetic
device such as a prosthetic knee or ankle. In certain embodiments,
the geo-magnetic sensor is also capable of determining the degree
of slope on which the user is traveling using, for example, the
tilt compensation function of certain embodiments of sensors. If
the geo-magnetic sensor determines that the device is on level
ground 130, the processing unit may then instruct the prosthetic
device to set parameters for level ground walking 140. If the
geo-magnetic sensor determines that the device is on stairs 160,
the processing unit may then instruct the prosthetic device to set
parameters for stair case walking 140. However, if the sensor
determines that the device is on stairs, but then senses a change
indicative of a 180.degree. turn 150, the processing unit may
notify the device to resume level ground walking 130 as the device
user is likely to be then traveling on a stair case landing. If the
geo-magnetic sensor determine that the device is on a slope 170,
the processing unit may then instruct the device to set parameters
for inclined or declined walking 140. Although FIG. 1B describes a
prosthetic knee system, it will be understood from the disclosure
herein that other types of prosthetic or orthotic systems (e.g.,
motion-controlled ankle systems) can also be used.
[0044] The ability of the geo-magnetic sensor to recognize abrupt
changes in direction is demonstrated in FIGS. 2A & 2B. FIGS. 2A
& 2B illustrate plots of a geo-magnetic signal charted against
the x, y, and z-axes for a prosthetic or orthotic device user as
the device user executes certain defined gait patterns. In FIG. 2A,
the device user is walking at a steady speed of between about 0.8
meters/second and about 1.2 meters/second. At a position
corresponding with sample number 600, the device user executes a
180.degree. turn. In certain embodiments, prosthetic or orthotic
devices can have difficulty registering this abrupt change in
direction, and the user would experience some instability of
movement, which could potentially be dangerous to the already
weakened limbs. For example, a typical sensor coupled to a
prosthetic or orthotic device, such as an accelerometer or
gyroscope, may only be able to measure the speed of movement and
not the directionality of movement. Therefore, an abrupt change in
direction could potentially throw the device user off-balance. As
can be seen at the position corresponding to sample number 600, the
geo-magnetic sensor advantageously registers a change in the
oscillatory pattern of all three axes and can alert the processing
unit that the user has shifted direction.
[0045] Similarly, a typical prosthetic or orthotic device can have
difficulty with adapting to a prosthetic or orthotic device user
who was rotating around the same spot. As described above, the
typical prosthetic or orthotic device would simply register that
the device was not rapidly changing in acceleration. Therefore, the
device user would not be able to compensate for the change in
direction and would likely be off-balanced in his or her movements.
Other sensors, such as accelerometers and gyroscopes, may have a
limited degree of directional sensing, but tend to drift off
because of the unexpected sensing pattern or time lag. These
sensors are oftentimes, therefore, impractical for rotational
movements where the direction continuously changes.
[0046] In contrast, geo-magnetic sensors measure direction directly
and are therefore more reliable as directional sensing devices.
Certain embodiments of the invention using the geo-magnetic sensor
can advantageously provide real time information regarding both the
orientation and the position data. FIG. 2B illustrates a plot of
the device user rotating around the same spot. As can be seen in
FIG. 2B, the geo-magnetic sensors demonstrate a shift in all three
axes at the location corresponding to around sample number 330. By
providing the processing unit with immediate information, the
prosthetic or orthotic device is able to adjust to new environments
with a much faster processing speed. While FIGS. 2A and 2B
illustrate the ability of the geo-magnetic sensor to recognize
abrupt changes in direction, such as a 180.degree. turn or rotation
around the same spot, certain embodiments can recognize any
directional change more than 20.degree.. In yet other embodiments,
the sensor can identify directional changes of less than
20.degree..
[0047] In certain embodiments, the geo-magnetic sensor may be
adapted for use with a knee device (or ankle device) for a
transtibial or transfemoral user. Such devices may include a lower
member that is moveable relative to an upper member at a natural
human joint location. The upper and the lower members may be
articulated about the joint location with respect to each other.
Such movement may be actively controlled by an actuator or at least
partially dampened, for example, by using a braking mechanism. In
certain embodiments, the braking mechanism can include a friction
brake, a magnetorheological brake, or a shape memory brake. FIG. 3
is a schematic illustration of an embodiment of a lower limb
prosthetic assembly, system or prosthesis 300 including an
electronically controlled active knee prosthetic assembly, system
or prosthesis 310. In certain embodiments, the knee prosthesis 310
provides resistive forces to substantially simulate the position
and motion of a natural knee joint during ambulation and/or other
locomotory or stationary activities performed by an amputee. The
prosthetic or artificial knee 310 is desirably safe, reliable and
generally comfortable to use by the amputee.
[0048] The prosthetic lower limb 300 further includes an artificial
or prosthetic foot 302 coupled or mechanically connected to a
pylon, tube, shaft or shank portion 304 that connects to a distal
or bottom portion of the prosthetic knee 310 and a residual limb or
stump socket 306 that connects to a top or proximal end of the
prosthetic knee 310. The stump socket 306 receives a residual limb
or femur portion 308 of the amputee. A suitable pylon or the like
can also be provided between the stump socket 306 and the
prosthetic knee 310, as needed or desired.
[0049] Embodiments of the invention can be practiced with a wide
variety of prosthetic feet or ankles. These include Flex-Foot.RTM.
feet such as Ceterus.RTM., LP Ceterus.RTM., Vari-Flex.RTM., LP
Vari-Flex.RTM., Talux.RTM., Elation.RTM., and Proprio Foot.RTM..
Some embodiments of suitable prosthetic feet and associated devices
are disclosed in U.S. Patent Application Publication No.
2005/0197717, published Sep. 8, 2005, U.S. Patent Application
Publication No. 2006/0224246, published Oct. 5, 2006, U.S. Patent
Application Publication No. 2006/0224247, published Oct. 5, 2006,
the entirety of each of which is hereby incorporated by reference
herein.
[0050] In certain embodiments, the geo-magnetic sensors may be
placed on the top or bottom of a prosthetic foot or ankle plate. In
other embodiments, the geo-magnetic sensors may be placed on an
ankle joint or the intersection between an ankle plate and a
transtibial member. In still other embodiments, the geo-magnetic
sensors may be place on an actuator. In still other embodiments,
the geo-magnetic sensor may be placed on a transtibial member. A
person of skill in the art would understand that these and other
embodiments are within the scope of the invention.
[0051] Embodiments of the invention can also be practiced with a
wider variety of prosthetic knees. These include, but are not
limited to the Power Knee.TM. and the Rheo Knee.RTM.. Some
embodiments of suitable prosthetic feet are disclosed in U.S. Pat.
No. 6,610,101, issued on Aug. 26, 2003, U.S. Pat. No. 6,764,520,
issued on Jul. 20, 2004, U.S. Pat. No. 7,314,490, issued on Jan. 1,
2008, U.S. Patent Application Publication No. 2006/0136072,
published Jul. 22, 2006, U.S. Patent Application Publication No.
2005/0283257, published Dec. 22, 2005, the entirety of each of
which is hereby incorporated by reference herein.
[0052] In certain embodiments, the geo-magnetic sensors may be
placed on a transtibial member. In other embodiments, the
geo-magnetic sensors may be placed on a knee joint or a socket. In
still other embodiments, the geo-magnetic sensors may be placed on
a transfemoral member. A person of skill in the art would
understand that these and other embodiments are within the scope of
the invention.
[0053] In certain embodiments, the prosthetic knee 310 of
embodiments of the invention permits the amputee to move and/or
adapt comfortably and safely in a wide variety of circumstances.
For example, during walking, running, sitting down, or when
encountering subtle or drastic changes in the terrain, topography
and environment or ambient conditions, such as, when the user lifts
a suitcase or walks down a slope or encounters stairs, among
others.
[0054] FIG. 4 shows a prosthetic knee assembly 410 generally
comprising the magnetorheological actuator assembly or system 412
and the frame and electronics assembly or system 414. The frame and
electronics assembly 414 also provides power and communicates with
the actuator assembly 412 via electrical signals.
[0055] In certain embodiments, the geo-magnetic sensor may be
adapted for use with an orthotic device. As seen in FIG. 5, the
orthotic device can be a Knee-Ankle-Foot device, which assists a
patient suffering from muscular weakness or other problems
affecting the patient's gait by providing support and compensation
for diminished muscular function or weakness.
[0056] Control of the knee and ankle joints 550, 592 by actuators
installed on, and working in conjunction with, the orthotic frame
500 allows the orthotic frame 500 to support a patient's weight
during certain activities, while also allowing flexion during other
activities. Various ambulatory and related activities performed by
a person place different requirements on the function of the
orthotic device. The upper and lower frames 530, 570 are preferably
adjustable in length, to accommodate fitting to patients of
different sizes and physical needs.
[0057] Referring to FIG. 6, the orthotic device is instrumented
with a multiple purpose sensor set 600, which enables measurement
of physical variables related to comfort (pressure and strain),
kinematics (sagittal plane angles of the knee and ankle joints,
rotational velocities of the shank and foot segments, and foot
accelerations, for example), orientation, knee joint and actuator
status, and other events related to ambulatory and related
activities, including aspects of the gait cycle such as, for
example, initial foot contact, foot flat, heel off, and toe
off.
[0058] Data gathered from the sensor set 600 may be analyzed for
biomechanical evaluation of the patient's use of the orthotic
device, which may be useful for fitting of the orthotic device as
well as monitoring the patient's progress and diagnosing problems
with the patient relating to the orthotic device.
[0059] Further, real-time analysis of the data from the sensor set
600 allows identification of ambulatory and related activities that
are performed by the patient, and can contribute to functional
compensation provided by the orthotic device. For example, in
addition to control of the knee device, it can be recognized that a
broader range of compensation strategies may be employed based on
recognition of different activities such as sitting down, standing
up, walking up or down stairs or a slope, or other activities that
may place different requirements on the functionality of the
orthotic device.
[0060] The sensor set may include pressure sensors 610, strain
gauges 620, a knee angle sensor 630, a knee status sensor 640, an
ankle angle sensor 650, inertial measurement units (IMUS) 660, foot
contact sensors 670, and geomagnetic sensors 680. An ambulatory
data processing unit (ambulatory unit) 700 can be co-located with
the orthosis (mounted to the orthotic frame 500 or carried by the
patient, for example), to monitor the sensors and to process sensor
data to control actuators of the orthotic device. The ambulatory
unit 700 also may provide data communication to a base unit 1000
where further analysis of the sensor data may be performed.
[0061] Pressure sensors 610 are disposed on portions of the
orthotic frame 500 that interface directly with a patient. In one
embodiment, the pressure sensors 610 are strain gages, located on
the lateral aspect of each pelotte carrier 585 and protected
against mechanical interactions and environmental factors.
[0062] Additionally, strain gauges 620 may be disposed on the
orthotic frame 500 to measure stresses on the components of the
orthotic frame 500 that are related to various ambulatory
activities. Strain gauges may be applied to the side bars 575 of
the upper and lower frames 530, 570 to measure deformation of the
side bars 575 that are related to loading of the side bars 575
during various ambulatory activities, to provide a measurement of
the loading.
[0063] A knee joint angle sensor 630 may be disposed on or
proximate to the knee joint 550, and configured to measure the knee
angle (an angle between the proximate and distal frame portions).
In one embodiment, the knee joint angle sensor 630 is a precision
potentiometer mounted on attaching members of the knee joint 550 to
measure the angle in one axis of the knee hinge.
[0064] An actuator lock mechanism sensor 640 can be disposed on or
proximate to the knee actuator 540 to sense the lock/unlock status
of the actuator lock mechanism. In one embodiment, the actuator
lock mechanism sensor 640 is a contact switch disposed to determine
and lock/unlock status of the actuator lock mechanism based on the
position of the actuator lock mechanism.
[0065] The actuator lock mechanism sensor 640 can be useful, in
addition to simply gathering information for biomechanical
evaluation of the orthotic device 510 or the patient, to provide an
audible or other signal or warning relating to the lock status of
the knee actuator 540. For example, a signal may be generated to
indicate to the patient that the knee actuator 540 has been locked,
so that the patient can confidently rely on the orthotic device to
support her weight. Similarly, an alarm may be generated if a
control signal has been sent to lock the knee actuator 540, but the
locking mechanism is not properly activated.
[0066] Inertial measurement units (IMUS) may be provided on the
shank (lower frame 570) and foot parts of the orthotic frame 500. A
foot IMU 660 may be positioned below the ankle joint and a shank
IMU 660 may be located along the lower (or shank) frame portion
570. The foot IMU 660 may be contained within a housing or small
box disposed below the ankle joint, and the shank IMU 660 may be
collocated with other electronics or interconnections in a junction
or interconnection box located along the shank (distal) frame
portion. Each of the IMUS 660 comprises a rate gyroscope and a
biaxial accelerometer.
[0067] In addition, or alternatively to the IMUS (and other
sensors), one or more linear accelerometers may be employed to
sense movement or kinematic information of any of the moving parts
of the orthotic frame 500. It can be recognized that such linear
accelerometers may be employed to provide movement or kinematic
information that is unavailable from, or that is redundant to,
other sensors.
[0068] Foot contact sensors 670 can be provided on the foot plate
594 in the form of pressure sensors or contact switches to detect
foot contact with the ground. Foot contact sensors 670 may be
located at both front and rear parts of the foot plate 594, to
detect both toe (or fore foot) and heel (or rear foot) contact
events. The foot contact sensors 670 may be disposed between the
foot plate 594 and a soft insole.
[0069] Alternative to foot contact sensors 670 provided on the foot
plate 594, pressure or contact or other types of sensors may be
deployed elsewhere on the orthotic frame 500 to sense foot contact
status such as foot strike or lift or related events. For example,
accelerometers may detect motion or impact associated with foot
strike or lift events, and strain gauges positioned variously about
the orthotic frame may provide information relating to the loading
of the orthotic frame that may be associated with foot strike and
lift events.
[0070] One or more geo-magnetic sensors 680 may be disposed on the
orthotic frame 500, such as for example a first end near the user's
legs, a second end near the user's upper torso, or at any other
location in between, and may provide information to the ambulatory
unit 700 alone or in combination with the other sensors and gauges.
In certain embodiments, the geo-magnetic sensor 680 monitors the
directionality of the orthotic device 510 by measuring a first,
second, and third data point, corresponding to the orientation
(e.g., roll, inclination, and azimuth angles) or the position data
(e.g., x, y, z), and sends the data to an ambulatory processing
unit 700. The processing unit 700 then compares the first, second,
and third data point to a database of predefined gait patterns,
such as stored in a memory of the prosthetic device and/or in
communication with the prosthetic device.
[0071] If the first, second, and third data point recorded over a
time interval matches one of the predefined gait patterns
designated as "unsafe," the processing unit 700 can send
instructions to the orthotic device 510 to issue a warning to alert
the device user. Examples of unsafe movements may include sharp
sudden turns, higher speed rotations about an axis, and steep
declines. In certain embodiments, the time interval over which the
data points are recorded is from about 1 millisecond to about 1
second. Thus, monitoring the orientation and providing feedback
control benefits the orthotic user by alerting the orthotic user of
any sudden shift in direction.
[0072] The ambulatory unit 700 can gather kinematic information
from the various sensors disposed on the orthotic frame 500. The
kinematic information may be processed locally by the ambulatory
unit 700, and may be used to control actuators (such as the knee
actuator 540) of the orthotic device in response to events or
conditions that are detected or recognized by the ambulatory unit
700 based on analysis of the kinematic data. The ambulatory unit
700 also may provide an interface for forwarding gathered data to
the base unit 1000 for further processing and analysis.
[0073] Referring to FIG. 7, the ambulatory unit 700 comprises
generally conventional control hardware architecture. Such a
control hardware architecture typically comprises a microprocessor
710 connected by a bus (not shown) to an area of main memory 720,
comprising both read only memory (ROM) 722, and random access
memory (RAM) 724.
[0074] The microprocessor 710 may be in communication, via the bus,
with a storage device 730 such as a disk storage device or a
removable media memory device such as a removable memory card or
the like. Input/output devices 740, 750 are included to provide an
interface to the sensors and actuators of the orthotic device
510.
[0075] A communication interface 760 is provided for communication
between the ambulatory unit 700 and the base unit 1000. The
communication interface 760 may be a wireless interface, employing
an RF, infra-red (IR), or other wireless communication medium.
Alternatively, the communication interface 760 may be wired, using
a cable in connection with the base unit 1000.
[0076] A control program may be stored in the ROM 722, or loaded
into memory 720 from storage device 730, for execution by the
microprocessor. The control program functions to read sensor data
from the sensor inputs, and to evaluate the sensor data for control
of actuators of the orthotic frame 500. The control program also
may store the sensor data in the storage device 730 for later
recall and transmission to the base unit 1000, or transmit the
sensor data to the base unit 1000 in real time.
[0077] The control program thus reads sensor data for both
real-time control of the orthotic device 510 and for later analysis
in the base unit 1000. Sensor data sampling rates for real-time
functions are typically higher than sampling rates for later
analysis. For example, a sampling rate of 100 Hz may be employed
for real-time control functions, while a sampling rate of 30 Hz may
be employed for data that is merely to be stored for later analysis
at the base unit. For data storage, it can be recognized that data
rate and the capacity of the storage device 730 influence the
amount of information that may be recorded for later analysis.
[0078] In the electro-mechanical approach to changing the biasing
force of the knee actuator 540, a control program executed by the
ambulatory unit 700 can determine when to signal the knee device to
select the rigid setting or the flexible setting. While a simple
control program may be employed to mimic the mechanical activation
of the knee actuator 540, by simply measuring the angle of flexion
of the ankle and unlocking the knee actuator 540 at a predetermined
angle, a more advanced control program may use a rule-based
detection algorithm for the cycle-to-cycle selection of the knee
actuator 540 setting based on a more comprehensive sampling of
kinetic data of the orthotic frame 500.
[0079] Input signals from the sensors may be periodically sampled
as inputs to the control program. The control program may consider
the knee angle, the ankle angle, the angular velocity of the shank
(lower frame 570), the current status of the knee actuator 540
(locked or unlocked), as well as other information.
[0080] FIG. 8 shows an embodiment of a hip orthosis 802 for
preventing the dislocation of a hip according to one embodiment of
the invention. In FIG. 8, the hip orthosis 802 has been fitted to a
person in standing position. The orthosis 802 is provided with an
upper leg engaging part 804, which is arranged for engaging an
upper leg of the person, in use, and a trunk engaging part 806,
which is arranged for engaging the trunk of the person, in use.
[0081] The trunk engaging part 806 may be provided with a trunk
girding part 836 which girds the trunk during use. The upper leg
engaging part 804 and the trunk engaging part 806 are intercoupled
by means of coupling means 808, 810. The coupling means comprise a
connecting part 808 connected with the upper leg engaging part 804
and a coupling part 810 connected with the trunk engaging part 806,
which parts 808, 810 are rotatable with respect to each other
during use.
[0082] In FIG. 8, reference numeral 825 designates a virtual point
of rotation, about which point of rotation the trunk engaging part
806 and upper leg engaging part 804 may be rotatable with respect
to each other. Here, the orthosis 802, in particular the trunk
engaging part 806, is designed such that the virtual point of
rotation 825 is, in use, substantially on a virtual line 824 which
intersects the two hip balls of the wearer of the orthosis. The
connecting part 808 reaches beyond the point of rotation 825,
viewed in a direction from the upper leg engaging part 804 towards
the point of rotation 825. The coupling part 810 engages the
portion of the connecting part 808 reaching beyond the point of
rotation 825. The connecting part 808 and the coupling part 810
engage with respect to each other in a point of contact 812.
[0083] In FIG. 8, the connecting part 808 may be provided with a
resilient element 814. In the embodiment shown, the resilient
element 814 comprises a leaf spring from, for instance, metal or
plastic. Due to the resilient element 814, the orthosis may be
capable of, operatively, exerting a force and/or a moment on the
upper leg which makes the upper leg abduct, viewed from the front
side of the person, preferably independently of the position of the
upper leg with respect to the trunk. In addition, the person has
more freedom of movement, since the upper leg can preferably move
in all direction. This offers more comfort and the possibility of
more efficient exercise of the muscles around the hip joint, which
muscles are weakened by, for instance surgery.
[0084] In use, the resilient element 814 can exert a force on the
upper leg engaging part 804 and the trunk engaging part 806, so
that the connecting part 808 and the coupling part 810 are
pretensioned with respect to each other. The force is direct such
that, in use, the resilient element 814 exerts a force F.sub.1
directed outwards on the upper leg via a lower pressure plate 816
of the upper leg engaging part 804, and a force F.sub.2 directed
inwards on the upper leg via an upper pressure plate 818 of the
upper leg engaging part 804. It will be clear that, in this
example, the force F.sub.1 may be thus directed transversely to the
sagittal plane, in the lateral direction, and the force F.sub.2 may
be thus directed transversely to the sagittal plane, in the medial
direction. It will be clear that the resilient element 814 may thus
exert moment on the upper leg engaging part 804 and consequently,
in use, on the upper leg.
[0085] The moment exerted on the upper leg may, for instance, press
the hip into its socket. In FIG. 8, the coupling part 810 is
provided with a sleeve 820 which prevents an outward movement of an
end 822 of the connecting part 808. Here, the end 822 of the
connecting part 808 is slidably positioned in the sleeve 820 of the
coupling part 810. Consequently, the resilient element 814 exerts a
force F.sub.1 directed outwards on the coupling part 810 via the
end 822 in the point of contact 812. In this example, the force
F.sub.1 may be thus directed transversely to the sagittal plane, in
the lateral direction, for instance along the virtual line 824. The
sleeve 820 can be designed as a rigid element from, for instance,
metal or plastic, but also as a flexible, elastic, or resilient
part from, for instance, rubber or (plastic) cloth.
[0086] In FIG. 8, the wearer of the orthosis is in a standing
position. The point of contact 812 is then substantially at some
distance above the point of rotation 825, and therefore above the
line 824. The lower and upper pressure plate 816 and 818,
respectively, are substantially below the line 824. As a result,
the resilient element 814 may effectively exert a force F and a
moment M on the hip joint of the upper leg, which joint is located
on line 824, which the force F is directed substantially inwards in
the embodiment shown in FIG. 8. In this example, the force F may be
thus directed transversely to the sagittal plane, in a medial
direction, for instance along the virtual line 824. As a result,
the hip is pressed into its socket, so that the risk of dislocation
is reduced further. In the embodiment shown in FIG. 8, the moment M
is directed such that the knee of the upper leg is pressed
substantially outwards, in a direction transverse to the sagittal
plane. As a result, too great an adduction of the upper leg (toward
the other leg), which increases the risk of dislocation of the hip,
can be prevented.
[0087] FIG. 9 illustrates the hip orthosis of FIG. 8 in an open
configuration. In certain embodiments, an accelerometer 910
determines the speed of the orthosis user. The geo-magnetic sensor
920 determines the directionality of the orthosis user and
initiates a warning in the form of vibration from vibrators 930
when the orthosis user makes a sudden change in direction that may
further injure the orthosis user. This sensor 920 coupled with a
warning system acts as a physical therapy training tool to help
train individuals with weakened limbs how to properly care for
their body. The hip orthosis also may include stretch sensors 940
and a battery device 950.
[0088] Warning systems may be provided in the prosthetic or
orthotic device to alert the user of an unsafe condition that may
lead to an injury and/or the impending activation of a feedback or
response mechanism. Such a warning system may be utilized to train
the user and or the user's muscles in the proper orientations of
the joint in order to avoid injuries. Such a warning system may
also be utilized to condition an amputee to utilize more efficient
biomechanical motions, for example, to achieve proper gait
dynamics.
[0089] For example, sudden changes in direction may cause
instability or even further injury to a device user with a weak
hip. If the geo-magnetic sensor senses that the device user is
about to execute a U-turn, the processor coupled to the
geo-magnetic sensor may trigger the warning system to issue an
alarm or vibration to alert the user to stop and use another
movement. In certain embodiments, the geo-magnetic sensor
facilitates such detection by sending sensory information related
to specific gait patterns to the processor, which can then trigger
the warning system to alert the prosthetic or orthotic device user
if a known unsafe movement is about to be executed. In certain
embodiments, the feedback system may dynamically add information to
the gait pattern database and the unsafe movement database based on
prior gait patterns and movements, which caused increased
instability.
[0090] As discussed in U.S. Patent Publication Nos. 2009/0024062
and 2009/0024065, both filed on Jul. 18, 2008, each of which is
hereby incorporated herein by reference in its entirety, the
warning system having feedback characteristics may include, in
certain embodiments, sensors, a processor, and one or more feedback
notification signals. The warning system may also have a locking
mechanism such as an array of air cells insertable into the
prosthetic or orthotic device, which inflate when triggered to
constrict the limb and prevent unsafe movements. The feedback
notification signals may include electric shocks or pulses,
flashing lights or LEDs, auditory signals, and tactile signals. The
auditory signals may include alarms, buzzers, beepers, whistles, or
sirens. The tactile signals may include heat or vibration.
[0091] The warning system may include a combination of signals or a
combination of signals and a locking mechanism. The warning system
may be graduated and begin, for example, by triggering one or more
feedback notification signals. If a device user chooses to ignore
the signals, the warning system may then trigger the locking
mechanism. The warning system may be categorized and trigger
different feedback notification signals or the locking mechanism
based on the assigned degree of danger of the predicted movement. A
signal may last for less than 10 second, less than 5 seconds, or
less than 1 second. In other embodiments, the signal will continue
until manually turned off. The locking mechanism may last for less
than 10 seconds, less than 5 seconds, or less than 1 second. In
other embodiments, the locking mechanism may remain locked until
manually released.
[0092] Moreover, certain control systems and modules described
herein may comprise software, firmware, hardware, or any
combination(s) of software, firmware, or hardware suitable for the
purposes described herein. Software and other modules may be
accessible via local memory, via a network, or via other means
suitable for the purposes described herein. Data structures or
indexes described herein may comprise computer files, variables,
programming arrays, programming structures, or any electronic
information storage schemes or methods, or any combinations
thereof, suitable for the purposes described herein.
[0093] Certain embodiments of the invention are also described
above with reference to flowchart illustrations and/or block
diagrams of methods, apparatus (systems) and computer program
products. It will be understood that each block of the flowchart
illustrations and/or block diagrams, and combinations of blocks in
the flowchart illustrations and/or block diagrams, may be
implemented by computer program instructions. These computer
program instructions may be provided to a processor of a general
purpose computer, special purpose computer, or other programmable
data processing apparatus to produce a machine, such that the
instructions, which execute via the processor of the computer or
other programmable data processing apparatus, create means for
implementing the acts specified in the flowchart and/or block
diagram block or blocks.
[0094] These computer program instructions may also be stored in a
computer-readable memory that can direct a computer or other
programmable data processing apparatus to operate in a particular
manner, such that the instructions stored in the computer-readable
memory produce an article of manufacture including instruction
means which implement the acts specified in the flowchart and/or
block diagram block or blocks. The computer program instructions
may also be loaded onto a computer or other programmable data
processing apparatus to cause a series of operations to be
performed on the computer or other programmable apparatus to
produce a computer implemented process such that the instructions
which execute on the computer or other programmable apparatus
provide means for implementing the acts specified in the flowchart
and/or block diagram block or blocks.
[0095] 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 disclosure.
Indeed, the novel methods and systems described herein may be
embodied in a variety of other forms; 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 disclosure. The accompanying claims and their
equivalents are intended to cover such forms or modifications as
would fall within the scope and spirit of the disclosure.
* * * * *