U.S. patent application number 13/349216 was filed with the patent office on 2012-10-11 for controlling powered human augmentation devices.
Invention is credited to Christopher E. Barnhart, Adrienne Bolger, Richard J. Casler, JR., David A. Garlow, Gary Girzon, Zhixiu Han, Hugh M. Herr, Jennifer T. McCarthy.
Application Number | 20120259430 13/349216 |
Document ID | / |
Family ID | 45541103 |
Filed Date | 2012-10-11 |
United States Patent
Application |
20120259430 |
Kind Code |
A1 |
Han; Zhixiu ; et
al. |
October 11, 2012 |
CONTROLLING POWERED HUMAN AUGMENTATION DEVICES
Abstract
In a communication system for controlling a powered human
augmentation device, a parameter of the powered device is adjusted
within a gait cycle by wirelessly transmitting a control signal
thereto, whereby the adjusted parameter falls within a target range
corresponding to that parameter. The target range is selected and
the device parameters are controlled such that the powered device
can normalize or augment human biomechanical function, responsive
to a wearer's activity, regardless of speed and terrain and, in
effect, provides at least a biomimetic response to the wearer of
the powered device.
Inventors: |
Han; Zhixiu; (Acton, MA)
; Barnhart; Christopher E.; (Carlisle, MA) ;
Garlow; David A.; (Lynnfield, MA) ; Bolger;
Adrienne; (Cambridge, MA) ; Herr; Hugh M.;
(Somerville, MA) ; Girzon; Gary; (Sudbury, MA)
; Casler, JR.; Richard J.; (Lowell, MA) ;
McCarthy; Jennifer T.; (Concord, MA) |
Family ID: |
45541103 |
Appl. No.: |
13/349216 |
Filed: |
January 12, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61432093 |
Jan 12, 2011 |
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Current U.S.
Class: |
623/24 |
Current CPC
Class: |
A61F 5/01 20130101; A61F
2/70 20130101; A61F 2002/7625 20130101; A61F 2/60 20130101; G05B
13/0205 20130101; A61F 2002/7635 20130101; A61F 2002/707 20130101;
A61F 2002/705 20130101; A61F 2002/6827 20130101; A61F 2002/7645
20130101; A61F 2/66 20130101; A61F 2/78 20130101 |
Class at
Publication: |
623/24 |
International
Class: |
A61F 2/48 20060101
A61F002/48 |
Claims
1. A method of controlling a powered human augmentation device, the
method comprising: adjusting a parameter of the powered device
within a gait cycle by wirelessly transmitting a control signal
thereto, whereby the adjusted parameter falls within a target range
corresponding to that parameter, providing at least a biomimetic
response to a wearer of the powered device.
2. The method of claim 1, wherein the parameter is selected from
the group consisting of net work, toe-off angle, peak power applied
by the powered device, and timing of the peak power relative to the
gait cycle.
3. The method of claim 1, wherein the target range corresponding to
the parameter is a function of at least one of ambulation speed and
ambulation pattern.
4. The method of claim 1, wherein the adjusting step is based at
least in part on at least one of ambulation speed and ambulation
pattern.
5. The method of claim 1, wherein the adjusting step is based at
least in part on at least one of terrain and activity.
6. The method of claim 5, wherein the activity is selected from the
group consisting of walking on level ground, walking on uneven
ground, walking upslope, walking downslope, ascending stairs, and
descending stairs.
7. The method of claim 1, wherein the adjusting step is related to
at least one of weight of the wearer, early-stance stiffness, power
applied by the powered device, timing of application of power,
hard-stop sensitivity, and a speed threshold for low-power mode of
the powered device.
8. The method of claim 7, wherein the adjusted parameter comprises
a gain in a positive force-feedback, whereby the power applied by
the powered device is adjusted.
9. The method of claim 7, wherein the adjusted parameter comprises
an exponent in a positive force-feedback, whereby the timing of the
application of power is adjusted.
10. The method of claim 1 further comprising the step of receiving
a data signal from the powered device, whereby adjusting the
parameter is based at least in part on the received data
signal.
11. The method of claim 10, wherein the received data signal is
related to at least one of rate of plantarflexion, heel rise, and
ambulation-step length.
12. The method of claim 1, wherein the control signal is
transmitted during at least one of a training mode and a use
mode.
13. The method of claim 1 further comprising the step of storing
the transmitted control signal for subsequent retransmission
thereof.
14. A communication system for interfacing with a powered human
augmentation device, the system comprising: a wireless transmitter
for adjusting a parameter of the powered device within a gait cycle
by transmitting a control signal thereto, whereby the adjusted
parameter falls within a target range corresponding to that
parameter, providing at least a biomimetic response to a wearer of
the powered device.
15. The system of claim 14, wherein the parameter is selected from
the group consisting of net work, toe-off angle, peak power applied
by the powered device, and timing of the peak power relative to the
gait cycle.
16. The system of claim 14, wherein the target range corresponding
to the parameter is a function of at least one of ambulation speed
and ambulation pattern.
17. The system of claim 14, wherein adjusting the parameter is
based at least in part on at least one of ambulation speed and
ambulation pattern.
18. The system of claim 14, wherein adjusting the parameter is
based at least in part on at least one of terrain and activity.
19. The system of claim 18, wherein the activity is selected from
the group consisting of walking on level ground, walking on uneven
ground, walking upslope, walking downslope, ascending stairs, and
descending stairs.
20. The system of claim 14, wherein adjusting the parameter is
related to at least one of weight of the wearer, early-stance
stiffness, power applied by the powered device, timing of
application of power, hard-stop sensitivity, and a speed threshold
for low-power mode of the powered device.
21. The system of claim 20, wherein the adjusted parameter
comprises a gain in a positive force-feedback, whereby the power
applied by the powered device is adjusted.
22. The system of claim 20, wherein the adjusted parameter
comprises an exponent in a positive force-feedback, whereby the
timing of the application of power is adjusted.
23. The system of claim 14, further comprising a receiver for
receiving a data signal from the powered device, wherein adjusting
the parameter is based at least in part on the received data
signal.
24. The system of claim 23, wherein the received data signal is
related to at least one of rate of plantarflexion, heel rise,
ambulation-step length.
25. The system of claim 14, wherein the control signal is
transmitted during at least one of a training mode and a use
mode.
26. The system of claim 14, wherein the wireless transmitter is
adapted to store the transmitted control signal for subsequent
retransmission thereof.
27. The system of claim 14, wherein the powered augmentation device
is selected from the group consisting of a prosthetic device and an
orthotic device.
28. The system of claim 14, wherein the wireless transmitter is
adapted to transmit the control signal to a second powered human
augmentation device.
29. The system of claim 14, wherein the wireless transmitter
comprises a transmitter of a mobile device.
30. The system of claim 29, wherein the mobile device is selected
from the group consisting of a cell phone, a personal digital
assistant, and a tablet PC.
31. An article of manufacture, comprising a non-transitory
machine-readable medium storing instructions that, when executed by
a processor, configure the processor to: adjust a parameter of the
powered device within a gait cycle by wirelessly transmitting a
control signal thereto, whereby the adjusted parameter falls within
a target range corresponding to that parameter, providing at least
a biomimetic response to a wearer of the powered device.
Description
RELATED APPLICATIONS
[0001] This application claims priority to and the benefit of U.S.
Provisional Patent Application Ser. No. 61/432,093, filed on Jan.
12, 2011, the entire content of which is hereby incorporated by
reference in its entirety.
FIELD OF THE INVENTION
[0002] This invention relates generally to powered human
augmentation devices, such as lower-extremity prosthetic orthotic,
or exoskelton apparatus, designed to emulate human biomechanics and
to normalize function, components thereof, and methods for
controlling the same.
BACKGROUND
[0003] Approximately 65% of service members seriously injured in
Iraq and Afghanistan sustain injuries to their extremities. Many of
these individuals experience muscle tissue loss and/or nerve
injury, resulting in the loss of limb function or substantial
reduction thereof. Injuries to the lower leg can be particularly
devastating, due to the critical importance of the ankle in
providing support for body position and in propelling the body
forward economically during common functions, such as level-ground
walking and the ascent and descent of stairs and slopes.
[0004] Increasingly, robotic technology is employed in the
treatment of individuals suffering from physical disability, either
for the advancement of therapy tools or as permanent assistive
devices. An important class of robotic devices provides therapy to
the arms of stroke patients. Additionally, lower-extremity robotic
devices have been developed for the enhancement of locomotor
function. Although decades of research has been conducted in the
area of active permanent assistive devices for the treatment of
lower-extremity pathology, many of these devices are not designed
to produce a biomimetic response, generally described in terms of
joint torque, joint angle, and other related parameters as observed
in a human not having substantial muscle tissue injury and not
using any device to assist in ambulation. Therefore, these robotic
devices may cause discomfort to the wearer. The commercially
available ankle-foot orthotic devices are generally passive,
non-adaptive devices.
[0005] Some powered prosthetic and orthotic devices have been
described in co-pending U.S. patent application Ser. No. 12/157,727
"Powered Ankle-Foot Prosthesis" filed on Jun. 12, 2008 (Publication
No. US2011/0257764 A1); co-pending U.S. patent application Ser. No.
12/552,013 "Hybrid Terrain-Adaptive Lower-Extremity Systems" filed
on Sep. 1, 2009 (Publication No. US2010/0179668 A1); co-pending
U.S. patent application Ser. No. 13/079564 "Controlling Power in a
Prosthesis or Orthosis Based on Predicted Walking Speed or
Surrogate for Same" filed on Apr. 4, 2011; co-pending U.S. patent
application Ser. No. 13/079571 "Controlling Torque in a Prosthesis
or Orthosis Based on a Deflection of Series Elastic Element" filed
on Apr. 4, 2011; and co-pending U.S. patent application Ser. No.
13/347443 "Powered Joint Orthosis" filed on Jan. 10, 2012. These
powered devices are adopted to provide at least a biomimetic
response and can eliminate or mitigate slapping of the foot after
heel strike (foot slap) and dragging of the toe during swing (toe
drag). In general, a biomimetic response refers to a range of
responses from humans and can vary according to the wearer of the
powered device and the nature and environment of the wearer's
activity. As such, even the powered devices described above need to
be tailored or calibrated to the wearer so as to reliably provide a
biomimetic response. Therefore, there is a need for systems and
methods of controlling permanent assistive devices for the
treatment of lower-extremity pathology to achieve optimal wearer
comfort and satisfaction.
SUMMARY
[0006] In various embodiments, the present invention provides
systems and methods that can dynamically control a powered
prosthetic/orthotic human augmentation device, such that the device
can provide and maintain at least a biomimetic response during the
wearer's activity. This is achieved, in part, by recording within a
gait cycle typical ranges of various ambulation-related parameters
in humans not having substantial muscle tissue injury and not using
any device to assist in ambulation. A user interface is provided
that enables an operator, the wearer, or another person to adjust
various parameters of the powered device such that the response of
the powered device, as described in terms of the ambulation-related
parameters, is substantially similar to the recorded ranges of
those parameters, i.e., at least biomimetic. These adjustments may
be carried out in a training mode, during actual use, or both. The
parameters of the powered device may also be adjusted or modified
according to the wearer's characteristics, such as weight, desired
walking speed, etc. and/or according to ambulation patterns, such
as slow walking, walking in incomplete steps or shuffling, etc.
Moreover, the parameters of the powered device may also be adjusted
or modified according to terrain and activity, e.g., walking
upslope, downslope, ascending and/or descending stairs, etc.
Accordingly, a biomimetic response of the powered
prosthetic/orthotic device can be maintained throughout the
duration of the wearer's activity, regardless of terrain, walking
speed, etc.
[0007] In one aspect, embodiments of the invention feature a method
of controlling a powered human augmentation device. The method
includes adjusting a parameter of the powered device within a gait
cycle by wirelessly transmitting a control signal thereto. After
adjustment based on the control signal, the adjusted parameter
falls within a target range corresponding to that parameter,
providing at least a biomimetic response to a wearer of the powered
device. The parameter may be net work, toe-off angle, peak power
applied by the powered device, or timing of the peak power relative
to the gait cycle. In some embodiments, more than one or even all
of these parameters are adjusted. The target range corresponding to
the parameter may be a function of ambulation speed and/or
ambulation pattern. The adjusting step may also be based, at least
in part, on one or more of the ambulation speed, ambulation
pattern, terrain, and activity. The activity may include walking on
level ground, walking on uneven ground, walking upslope, walking
downslope, ascending stairs, and/or descending stairs.
[0008] In some embodiments, the adjusting step is related to one or
more of weight of the wearer, early-stance stiffness, power applied
by the powered device, timing of application of power, hard-stop
sensitivity, and a speed threshold for low-power mode of the
powered device. The adjusted parameter may also include a gain in a
positive force-feedback control loop that can adjust the power
applied by the powered device and/or an exponent in a positive
force-feedback that can adjust the timing of the application of
power.
[0009] In some embodiments, the method includes the step of
receiving a data signal from the powered device, such that
adjusting the parameter is based at least in part on the received
data signal. The received data signal may be related to one or more
of rate of plantar flexion, heel rise, and ambulation-step length.
The control signal may be transmitted during a training mode, a use
mode, or both. The method may also include the step of storing the
transmitted control signal for subsequent retransmission
thereof.
[0010] In another aspect, a communication system for interfacing
with a powered human augmentation device includes a wireless
transmitter for adjusting a parameter of the powered device. The
parameter is adjusted within a gait cycle by transmitting a control
signal to the powered device, such that the adjusted parameter
falls within a target range corresponding to that parameter. This
provides at least a biomimetic response to a wearer of the powered
device.
[0011] The parameter may be net work, toe-off angle, peak power
applied by the powered device, or timing of the peak power relative
to the gait cycle. In some embodiments, more than one or even all
of these parameters are adjusted. The target range corresponding to
the parameter may be a function of ambulation speed and/or
ambulation pattern. The adjustment of the parameter may also be
based, at least in part, on one or more of the ambulation speed,
ambulation pattern, terrain, and activity. The activity may include
walking on level ground, walking on uneven ground, walking upslope,
walking downslope, ascending stairs, and/or descending stairs.
[0012] In some embodiments, the parameter adjustment is related to
one or more of weight of the wearer, early-stance stiffness, power
applied by the powered device, timing of application of power,
hard-stop sensitivity, and a speed threshold for low-power mode of
the powered device. The adjusted parameter may also include a gain
in a positive force-feedback control loop that can adjust the power
applied by the powered device and/or an exponent in a positive
force-feedback that can adjust the timing of the application of
power.
[0013] In some embodiments, the communication system includes a
receiver for receiving a data signal from the powered device, such
that adjusting the parameter is based at least in part on the
received data signal. The received data signal may be related to
one or more of rate of plantar flexion, heel rise, and
ambulation-step length. The control signal may be transmitted
during a training mode, a use mode, or both. The communication may
also store the transmitted control signal for subsequent
retransmission thereof.
[0014] The powered augmentation device may be a prosthetic device
or an orthotic device, such as an exoskeleton. In some embodiments,
the wireless transmitter is adapted to transmit the control signal
to a second powered human augmentation device. The wireless
transmitter may include a transmitter of a mobile device, and the
mobile device can be a cell phone, a personal digital assistant, or
a tablet PC.
[0015] In yet another aspect, various embodiments feature an
article of manufacture, including a non-transitory machine-readable
medium storing instructions. The instructions, when executed by a
processor, configure the processor to adjust a parameter of the
powered device within a gait cycle by wirelessly transmitting a
control signal thereto. After adjustment based on the control
signal, the adjusted parameter falls within a target range
corresponding to that parameter, providing at least a biomimetic
response to a wearer of the powered device.
[0016] These and other objects, along with advantages and features
of the embodiments of the present invention herein disclosed, will
become more apparent through reference to the following
description, the accompanying drawings, and the claims.
Furthermore, it is to be understood that the features of the
various embodiments described herein are not mutually exclusive and
can exist in various combinations and permutations. As used herein,
the term "substantially" means.+-.10% and, in some embodiments,
.+-.5%.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In the drawings, like reference characters generally refer
to the same parts throughout the different views. Also, the
drawings are not necessarily to scale, emphasis instead generally
being placed upon illustrating the principles of the invention. In
the following description, various embodiments of the present
invention are described with reference to the following drawings,
in which:
[0018] FIG. 1 depicts an exemplary prosthetic device and a
communication system according to one embodiment;
[0019] FIGS. 2a-2d depict various joint parameters within a gait
cycle, describing respective biomimetic responses;
[0020] FIGS. 3a-3e depict steps of adjusting various parameters of
a powered device according to one embodiment; and
[0021] FIG. 4 shows various parameters of a powered device that may
be adjusted, and the ranges of those parameters, according to one
embodiment.
DESCRIPTION
[0022] The entire contents of each of U.S. patent application Ser.
No. 12/157,727 "Powered Ankle-Foot Prosthesis" filed on Jun. 12,
2008 (Publication No. US2011/0257764 A1); U.S. patent application
Ser. No. 12/552,013 "Hybrid Terrain-Adaptive Lower-Extremity
Systems" filed on Sep. 1, 2009 (Publication No. US2010/0179668 A1);
U.S. patent application Ser. No. 13/079564 "Controlling Power in a
Prosthesis or Orthosis Based on Predicted Walking Speed or
Surrogate for Same" filed on Apr. 4, 2011; U.S. patent application
Ser. No. 13/079571 "Controlling Torque in a Prosthesis or Orthosis
Based on a Deflection of Series Elastic Element" filed on Apr. 4,
2011; and U.S. patent application Ser. No. 13/347443 "Powered Joint
Orthosis" filed on Jan. 10, 2012 are incorporated herein by
reference. FIG. 1 shows a BiOM.TM. Ankle 102, a powered prosthetic
ankle available from iWalk, Inc. (Bedford, Mass.), and a smart
phone 104 for controlling/tuning various parameters of the BiOM
Ankle 102. The smart phone 104 includes a transmitter 106 for
sending one or more control signals to the BiOM Ankle 102, whereby
one or more parameters of the BiOM Ankle 102 can be adjusted. The
smart phone 104 also includes a receiver 108 for receiving
parameter values as data signals from the BiOM Ankle 102 which has
a corresponding transmitter and receiver capability. These data
signals can be used to adjust the values of the corresponding
and/or other parameters of the BiOM Ankle 102. To facilitate
convenient adjustment of various parameters, the BiOM Ankle 102
provides a user interface that includes a software application and
firmware. The software application, implemented in Java for the
Android 2.1 Operating System, may be run on the smart phone 104.
The software application builds a packet structure that is sent out
over Android's Bluetooth hardware interface. Corresponding software
on the BiOM Ankle 102, written in C and stored in the firmware of
the BiOM Ankle 102, receives commands from the same packet
structure, and adjusts the operation of the BiOM Ankle 102
accordingly.
[0023] It should be understood that the BiOM Ankle 102 and the
smart phone 104 are illustrative only and, in general, a powered
human augmentation device can be any powered prosthetic, orthotic
and/or exoskeleton device that can assist in ankle, knee, and/or
hip function. Uses in other joint devices are also contemplated.
The communication system, in general, can be any mobile
communication device capable of communicating with the powered
device. Exemplary mobile communication devices include smart
phones, personal digital assistants (PDAs, such as a BlackBerry),
tablet computers, etc. The communication between the communication
system and the powered device may be established via wireless link
such as Bluetooth, WiFi, etc., or via a wired link. The software
applications run on the BiOM Ankle 102 and the smart phone 104 may
also be written in any other programming languages and/or may be
provided as circuitry.
[0024] Various parameters of the BiOM Ankle 102 (or in any powered
human augmentation device, in general) are controlled using the
smart phone 104, such that the BiOM Ankle 102 produces at least a
biomimetic response. Such a response may enable a wearer of the
powered device to ambulate in a natural manner, e.g., in a manner
in which a typical human not using a powered device walks (i.e.,
slowly or briskly), ascends/descends stairs, etc. In addition to
enabling ambulation with a natural feel, a powered device producing
at least a biomimetic response can also decrease stress on other
body parts of the human, e.g., on knees and hips while using the
BiOM Ankle 102. As a result, net metabolic cost of transport to the
wearer can be minimized.
[0025] In one embodiment, a biomimetic response of a human can be
characterized by four parameters, namely, net work, toe-off angle,
peak power, and peak-power timing. Each of these parameters varies
according to the human's ambulation speed. Net work is the time
integral of mechanical power applied by the powered device (e.g.,
the BiOM Ankle 102) during one ambulation step (i.e., gait cycle).
FIG. 2a shows that for typical humans, who do not have injured
muscle tissue and do not use a powered augmentation device, the net
work normalized according to the human's weight varies according to
the walking speed, but stays within a certain range. For example,
at a walking speed of about 1.5 m/s, the normalized net work may be
in the range of about 0.1-0.25 J/kg, and at a walking speed of
about 2 m/s the normalized net work may be in the range of about
0.2-0.4 J/kg.
[0026] A net-work response of a powered augmentation device is
biomimetic if the net work produced by the device remains within a
range corresponding to the ambulation speed, i.e., substantially
within the dashed lines 202, 204. If the net-work response of the
powered device falls outside the range indicated by the lines 202,
204, one or more parameters of the device can be tuned using the
communication system, e.g., the smart phone 104, (as described
below), such that the net work is adjusted to fall within a desired
range.
[0027] FIG. 2b depicts a relationship between the toe-off angle and
walking speed for a typical human. If the toe-off angle while using
a powered augmentation device is not substantially the same as that
indicated by the dashed line 206, the foot may not be
plantarflexing sufficiently. Therefore, one or more parameters of
the powered device (e.g., BiOM Ankle 102) may be tuned using the
smart phone 104.
[0028] FIGS. 2c and 2d depict the peak power delivered by a typical
human and timing within a gait cycle at which the peak power is
delivered, respectively. If the peak power to the ankle (a joint,
in general) delivered by a powered augmentation device does not
fall within the range indicated by the dashed lines 208, 210, the
wearer receives too little or too much power. If the powered
augmentation device delivers the peak power at a time less than
that indicated by line 212, the peak power may be delivered too
early, i.e., significantly before the time at which the powered
plantar flexion state of the gait cycle begins. In this case, the
wearer might feel that the ankle is lifting up but not
pushing/propelling forward sufficiently. On the other hand, if the
powered augmentation device delivers the peak power at a time
substantially greater than that indicated by the line 212, the peak
power may be delivered too late, i.e., significantly after the time
at which the powered plantar flexion state of the gait cycle
begins. In this case, the wearer might feel that the ankle is
pushing forward but not lifting up sufficiently.
[0029] In any of the scenarios describe above, unlike a typical
human, the wearer may not receive adequate power to the ankle at
the time of toe off, resulting in unnatural ambulation. Therefore,
one or more parameters of the powered device may be adjusted such
that at a certain ambulation speed the peak power applied by the
device remains substantially within the range indicated by the
dashed lines 208, 210. Moreover, one or more parameters may also be
adjusted such that the timing within the gait cycle at which the
powered device delivers the peak power corresponds generally to
that indicated by the line 212.
[0030] In general, by tuning one or more parameters of the powered
augmentation device using a communication system, each of the net
work, toe-off angle, peak power, and peak power timing can be
adjusted, such that the powered device delivers at least a
biomimetic response to the wearer. In some instances, the
parameters such as the peak power and peak power timing can be
adjusted directly. In other instances, other related parameters,
e.g., heel stiffness, are adjusted using the communication system,
which in turn causes an adjustment of the parameters described with
reference to FIGS. 2a-2d.
[0031] With reference to FIGS. 3a-3e, in an exemplary tuning
process 300, a communication system (phone for convenience,
hereafter) scans for a powered augmentation device within the
phone's range, in step 302. When any such devices are located, one
of them may be selected and a Bluetooth connection is established
with that device in step 304, pairing the phone with the selected
powered device. In general, the phone can be paired with more then
one powered devices. In step 306, the wearer's ID and weight are
entered and the transmitter of the phone may supply the weight to
the paired power device by sending a control signal thereto. The
wearer's weight may range from about 100 lbs up to about 300 lbs.
Various parameters of the powered device adjusted subsequently may
be adjusted according to the wearer's weight.
[0032] In step 308, a powered ankle device is tuned by selecting
"Tune Ankle." In other embodiments, other joints such as knee or
hip may be tuned alternatively or in addition. In step 310, the
wearer walks at a self-selected walking speed (SSWS), and an
operator i.e., the wearer himself/herself or another person
(clinician, researcher, etc.) adjusts "stiffness," e.g., by
gradually increasing it from zero. In response, the rate of plantar
flexion may change, which is observed by the operator, or the
wearer may inform it to the operator. In some embodiments, a sensor
of the powered device may sense the rate of plantar flexion and may
transmit a corresponding data signal to the phone. The phone may
then display the sensed rate to the operator. In the step 308, the
operator adjusts the stiffness so as to achieve a desired rate of
plantar flexion which, in turn, adjusts one or more of the net
work, toe-off angle, peak power, and peak power timing.
[0033] In step 312, the power applied by the powered augmentation
device is adjusted by asking the wearer to walk at SSWS. The
operator gradually increases the power from an initial value (e.g.,
zero percent) until the wearer verifies that powered plantar
flexion is engaged correctly, i.e., adequate power is received
approximately at the time the ankle dorsiflexion is at a maximum
level. Increasing (decreasing) the power may include increasing
(decreasing) a gain parameter in a positive-feedback system of the
powered device that delivers the power. In some embodiments,
correct engagement of the powered plantar flexion can be verified
by analyzing various sensors signals detected by the powered
augmentation device and transmitted to the communication system as
data signals. The received data signals may relate to parameters
such as heel rise, walking-step length, and tracking performed
during the swing phase. The operator may also manually (e.g.,
visually) compare values of these parameters with their values
corresponding to a previous power setting, so as to identify the
power setting that results in at least a biomimetic response as
described above and/or the wearer's preference.
[0034] The timing at which peak power is applied by the powered
augmentation device (e.g., the BiOM Ankle 102 shown in FIG. 1) is
adjusted in step 314 by asking the wearer to walk at SSWS. The
operator adjusts the "Power Trigger" timing such that power is
delivered at terminal stance, i.e., approximately at the time the
ankle dorsiflexion is at a maximum level. Adjusting the power
timing may include adjusting an exponent parameter in a
positive-feedback system that delivers the power. Whether the
timing is correct may be verified by the wearer. The operator may
also verify that gait cycle is balanced and that a desired knee
flexion is maintained during stance. Alternatively, or in addition,
data signals corresponding to various parameters of the powered
device may be received therefrom, and used to guide adjustment of
the power trigger. Adjusting the timing of application peak power
enables timely powered plantar flexion at toe off. This adjustment
can also allow the wearer to take a full step using the leg having
any injured muscle tissue.
[0035] When a wearer prefers to walk at a speed slower than the
SSWS, the parameters of the powered device may be readjusted, to
provide a biomimetic response corresponding to the slower speed, in
part, and also to conserve battery life, in part. To this end, in
step 316, the wearer is asked to walk at a slower speed, and the
power is adjusted down from an initial value (e.g., 100%) which may
be the power setting for the SSWS, to a "slow-walk mode" setting.
The power may be adjusted according to the wearer's preference
and/or according to parameters such as heel rise, walking-step
length, and tracking performed during the swing phase. The values
of these parameters may be received from the powered device as data
signals and/or may be observed by the operator similarly as
described in the step 310.
[0036] The slow-walk mode can also be used to adjust parameters
according to the wearer's ambulation pattern, e.g., when the wearer
does not take full steps or shuffles. In the step 318, a threshold
at which the BiOM Ankle's slow-walk mode, also called "low-power"
mode engages can also be adjusted. In addition to conserving
battery life, the slow-walk mode setting can increase walking
efficiency at a slower speed and can also enhance the real-time
response of the ankle.
[0037] In step 320, the hard-stop sensitivity of the powered device
can be adjusted. The hard stop corresponds to the wearer's walking
speed, and the maximum dorsiflexion angle embodied within the
design of the powered device. Generally, the small angular
displacements that occur after engagement of the hard-stop are used
to estimate ankle torque. This torque is an important input to the
positive force feedback. By slightly changing this torque model
parameter, an increased or decreased reflex torque adjustment can
be made which is particularly useful for slow walking performance.
The hard-stop sensitivity can be increased such that the powered
device delivers more power (e.g., compared to the power setting for
the SSWS) early in the gait cycle, and the hard-stop sensitivity
can be decreased such that relatively less power is delivered later
in the gait cycle.
[0038] The communication device can also facilitate adapting the
powered device to terrain and/or the wearer's activity. For
example, power and/or timing of peak power can be adjusted to
provide additional power when the wearer is walking upslope. These
adjustment can be made as described with reference to the steps
312, 314. If the wearer is walking downslope, these parameters can
be adjusted to provide adequate plantar flexion and knee stability
when the foot rests flat on a surface. The phone (the communication
system, in general) can set the powered device to operate in "Stair
Mode." In this mode, the wearer is asked to ascend stairs, landing
on the toe of a leg having affected muscle tissue. Various device
parameters may be adjusted as described above with reference to the
steps (power applied, in particular, as described in step 312) so
that the powered augmentation device delivers at least a biomimetic
response. The wearer may also be asked to descend stairs and the
device parameters may be adjusted for descending stairs.
[0039] In step 328, the various device parameters adjusted in any
of these steps can be saved for subsequent use. The
tuning/adjusting described above may be performed in a training
mode in one or more training sessions. More than one sets of
settings, each set corresponding to one training session, may be
saved for each joint (ankle, knee, hip, etc.), and may be restored
during a subsequent use. The tuning/adjusting described above may
also be performed during actual use of the powered device.
[0040] The ranges of various parameters described above with
reference to FIGS. 3a-3e according to one embodiment are shown in a
Table in FIG. 4. The Table shows additional parameters of the
powered device that may be adjusted, so as to achieve and maintain
at least a biomimetic response, and typical ranges of those
parameters. It should be understood that the parameters shown in
the Table are illustrative, and that according to some embodiments
fewer or additional parameters may be controlled. Some other
embodiments may control different parameters, and/or the typical
ranges within which the parameters can be set may be different.
[0041] Accordingly, various embodiments of the invention may be
used to initially set up or tune an augmentation device at the time
of manufacture and commissioning to achieve a biomimetic response,
on an individual employed as a model for this purpose. The device
can then be fitted to the end user and the device further adjusted
to tailor the device to that individual. As described, achieving a
biomimetic response is a primary objective, in order to order to
normalize user function and satisfaction. However, the methods and
systems according to various embodiments of the invention may be
used to achieve a greater than biomimetic response, or vary one or
more of the response parameters as desired by the user or the
user's physician, therapist, or clinician. Naturally, as will be
understood, changes in a user's weight, strength, endurance or
other physical condition may require further monitoring and
adjustment of the device over time. Accordingly, the systems and
associated methods may be utilized on regular time intervals or
whenever a change to user or device occurs that warrants
checking.
[0042] While the invention has been particularly shown and
described with reference to specific embodiments, it will be
understood by those skilled in the art that various changes in form
and detail may be made therein without departing from the spirit
and scope of the invention as defined by the appended claims. The
scope of the invention is thus indicated by the appended claims and
all changes that come within the meaning and range of equivalency
of the claims are therefore intended to be embraced.
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