Canadian Patents Database / Patent 2543061 Summary

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(12) Patent: (11) CA 2543061
(54) English Title: INSTRUMENTED PROSTHETIC FOOT
(54) French Title: PROTHESE DE PIED INSTRUMENTEE
(51) International Patent Classification (IPC):
  • A61F 2/66 (2006.01)
  • A61F 2/68 (2006.01)
  • A61F 2/76 (2006.01)
(72) Inventors :
  • BEDARD, STEPHANE (Canada)
  • ROY, PIERRE-OLIVIER (Canada)
(73) Owners :
  • VICTHOM LABORATORY INC. (Canada)
(71) Applicants :
  • VICTHOM HUMAN BIONICS, INC. (Canada)
(74) Agent: SIM & MCBURNEY
(45) Issued: 2012-01-24
(86) PCT Filing Date: 2003-11-18
(87) PCT Publication Date: 2005-06-02
Examination requested: 2008-10-06
(30) Availability of licence: N/A
(30) Language of filing: English

English Abstract




The present application discloses an instrument prosthetic foot (20) for use
with an actuated leg prothesis (14) controlled by a controller, the
instrumented prosthetic foot (20) comprising a connector to connect the
instrumented prosthetic foot (20) to the leg prothesis (14), an ankle
structure connected to the connector, a ground engaging member connected to
the ankle, at least one sensor (22a, 22b, 24a, 24b, 26) for detecting changes
in weight distribution along the foot, and an interface for transmitting
signals from the sensor to the controller.


French Abstract

La présente invention se rapporte à une prothèse de pied instrumentée (20), destinée à être utilisée avec une prothèse de jambe (14) actionnée et commandée par un dispositif de commande. La prothèse de pied instrumentée (20) selon l'invention comprend un dispositif de liaison permettant de relier la prothèse de pied instrumentée (20) à la prothèse de jambe (14), une structure de cheville reliée au dispositif de liaison, un élément de contact avec le sol relié à la cheville, au moins un capteur (22a, 22b, 24a, 24b, 26) conçu pour détecter les variations de la répartition du poids le long du pied, ainsi qu'une interface destinée à transmettre au dispositif de commande les signaux émanant du capteur.


Note: Claims are shown in the official language in which they were submitted.



13

What is claimed is:


1. An instrumented prosthetic foot, the instrumented prosthetic foot
comprising:
an elongated foot plate having a top and a bottom part;
an ankle structure pivotally connected to the elongated foot plate top
part;
a connector to operably connect the instrumented prosthetic foot to a
user;
a first rotational sensor positioned on the ankle structure about its pivot
axis with the elongated foot plate, the first sensor being configured to
measure
the rotation of the ankle structure about its pivot axis; and
a second sensor interposed between the connector and the ankle
structure, the second sensor being configured to measure the pressure force
on the connector;
wherein the ankle structure and second sensor are connected between
the connector and the top part.


2. An instrumented prosthetic foot according to claim 1, wherein the first
sensor is an optical encoder.


3. An instrumented prosthetic foot according to claim 1 or 2, wherein the
second sensor is a load cell.


4. An instrumented prosthetic foot according to any one of claims 1 to 3,
wherein the first and second sensor are configured to transmit signals to a
controller of an actuated leg prosthesis using a wired connection


5. An instrumented prosthetic foot according to any one of claims 1 to 3,
wherein the first and second sensor are configured to transmit signals to a
controller of an actuated leg prosthesis using a wireless connection.



14

6. An instrumented prosthetic foot according to any one of claims 1 to 3,
wherein the first and second sensor are configured to transmit signals to a
controller of an actuated leg prosthesis using an optical interface.


7. An instrumented prosthetic foot according to any one of claims 1 to 6,
wherein the connector removably connects the instrumented prosthetic foot to
a leg prosthesis.


8. An instrumented prosthetic foot according to claim 1, wherein the
second sensor is configured to measure an axial force on the connector.

9. An instrumented prosthetic foot system, the system comprising:
an instrumented foot comprising an elongated foot plate having a top
and a bottom part and a toe and a heel region;
an ankle structure pivotally connected to the elongated foot plate top
part;
a connector to connect the instrumented prosthetic foot to the leg
prosthesis;
a first rotational sensor positioned on the ankle structure about its pivot
axis with the elongated foot plate configured to measure the rotation of the
ankle structure about its pivot axis;
a second sensor interposed between the connector and the ankle
structure configured to measure the pressure force on the connector; and
a controller configured to receive data relative to the position of the ankle
structure about its pivot axis from the first sensor and to the pressure force
on
the connector from the second sensor, and configured to determine the torque
between the elongated foot plate top part and the connector using the received

data.


10. An instrumented prosthetic foot system according to claim 9, wherein the
controller further determines the pressure force on the toe and the heel
region
of the elongated foot plate using the received data.



15

11. An instrumented prosthetic foot system according to claim 9, wherein the
controller determines the torque via the following equation:

M = R ANKLE R CONST
where
M is the torque;
R ANKLE is the data relative to rotation of the ankle structure about
its pivot axis measured by the first sensor; and
R CONST is a constant associated with the rotation of the ankle
about its axis.


12. An instrumented prosthetic foot system according to claim 11, wherein
the controller further determines the pressure force on the toe and the heel
region of the elongated foot plate via the following equation:

F TOE = (M + F S2 L HEEL) / (L HEEL + L TOE)
F HEEL = (-M + F S2 L TOE) (L HEEL + L TOE)
where
F S2 is the pressure force measured by the second sensor;
F TOE is the pressure force on the toe region of the elongated foot
plate;
F HEEL is the pressure force on the heel region of the elongated
foot plate;
L TOE is the distance between a center of the connector and a
center of the toe region; and
L HEEL is the distance between the center of the connector and a
center of the heel region.


13. An instrumented prosthetic foot system according to any one of claims 9
to 12, wherein the first and second sensor transmit signals to the controller
using a wired connection.



16

14. An instrumented prosthetic foot system according to any one of claims 9
to 12, wherein the first and second sensor transmit signals to the controller
using a wireless connection.


15. An instrumented prosthetic foot system according to any one of claims 9
to 12, wherein the first and second sensor transmit signals to the controller
using an optical interface.


16. An instrumented prosthetic foot system according to claim 9, wherein the
connector removably connects the instrumented prosthetic foot to a leg
prosthesis.


17. An instrumented prosthetic foot system according to any one of claims 9
to 16, wherein the first sensor is an optical encoder.


18. An instrumented prosthetic foot system according to any one of claims 9
to 17, wherein the second sensor is a load cell.


19. An instrumented prosthetic foot system according to claim 9, wherein the
second sensor is configured to measure an axial force on the connector.

Note: Descriptions are shown in the official language in which they were submitted.


CA 02543061 2011-01-27

INSTRUMENTED PROSTHETIC FOOT
BACKGROUND
As is well known to control engineers, the automation of complex mechanical
systems is not something easy to achieve. Among such systems, conventional
powered artificial limbs are notorious for having control problems. These
conventional prostheses are equipped with basic controllers that artificially
mobilize
the joints without any interaction from the amputee and are only capable of
generating basic motions. Such basic controllers do not take into
consideration the
dynamic conditions of the working environment, regardless the fact that the
prosthesis is required to generate appropriate control within a practical
application.
They are generally lacking in predictive control strategies necessary to
anticipate
the artificial limb's response as well as lacking in adaptive regulation
enabling the
adjustment of the control parameters to the dynamics of the prosthesis.
Because
human limb mobility is a complex process including voluntary, reflex and
random
events at the same time, conventional prostheses do not have the capability to
interact simultaneously with the human body and the external environment in
order
to have minimal appropriate functioning.

Accordingly, it is an object of the present application to obviate or mitigate
some or
all of the above disadvantages.

SUMMARY
According to the present invention, there is provided an instrumented
prosthetic
foot, the instrumented prosthetic foot comprising:
an elongated foot plate having a top and a bottom part;
an ankle structure pivotally connected to the elongated foot plate top part;
a connector to operably connect the instrumented prosthetic foot to a user;
a first rotational sensor positioned on the ankle structure about its pivot
axis
with the elongated foot plate, the first sensor being configured to measure
the
rotation of the ankle structure about its pivot axis; and
a second sensor interposed between the connector and the ankle structure,
the second sensor being configured to measure the pressure force on the


CA 02543061 2011-01-27

1a
connector;
wherein the ankle structure and second sensor are connected between the
connector and the top part.

According to another aspect of the present invention, there is provided an
instrumented prosthetic foot system, the system comprising:
an instrumented foot comprising an elongated foot plate having a top and a
bottom part and a toe and a heel region;
an ankle structure pivotally connected to the elongated foot plate top part;
a connector to connect the instrumented prosthetic foot to the leg prosthesis;
a first rotational sensor positioned on the ankle structure about its pivot
axis
with the elongated foot plate configured to measure the rotation of the ankle
structure about its pivot axis;
a second sensor interposed between the connector and the ankle structure
configured to measure the pressure force on the connector; and
a controller configured to receive data relative to the position of the ankle
structure about its pivot axis from the first sensor and to the pressure force
on the
connector from the second sensor, and configured to determine the torque
between
the elongated foot plate top part and the connector using the received data.


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2
BRIEF DESCRIPTION OF THE FIGURES

Embodiments of the invention will be described by way of example only with
reference to the accompanying drawings, in which:

FIG. I shows the lower body of an individual provided with a prosthesis and an
instrumented prosthetic foot on one side and having a healthy leg on the other
side.

FIG. 2 is a block diagram showing a control system for a prosthesis having an
actuating mechanism.

FIG. 3 is a perspective view, from the front and slightly above, of a
instrumented
prosthetic foot.

FIG. 4 is an exploded perspective view of the instrumented prosthetic foot of
FIG. 3.

FIG. 5 is a perspective view, from the front and slightly above, of an
alternative
embodiment of the instrumented prosthetic foot of FIG. 3.

FIG. 6 is an exploded perspective view of the instrumented prosthetic foot of
FIG. 5.

FIG. 7 is a perspective view, from the front and slightly above, of another
alternative embodiment of the instrumented prosthetic foot of FIG. 3

FIG. 8 is an exploded perspective view of the instrumented prosthetic foot of
FIG. 7.

FIG. 9 is schematic view of forces exerted on a foot.

FIG. 10 is a perspective view, from the front and slightly above, of a further
still
alternative embodiment of the instrumented prosthetic foot of FIG. 3

FIG. 11 is an exploded perspective view of the instrumented prosthetic foot of
FIG. 10.


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3
FIG. 12 is a perspective view, from the front and slightly above, of a yet
further still
alternative embodiment of the instrumented prosthetic foot of FIG. 3

FIG. 13 is an exploded perspective view of the instrumented prosthetic foot of
FIG. 12.

FIG. 14 is a perspective view, from the front and slightly above, of a further
alternative embodiment of the instrumented prosthetic foot of FIG. 3

FIG. 15 is an exploded perspective view of the instrumented prosthetic foot of
FIG. 14.

DETAILED DESCRIPTION

The appended figures show a instrumented prosthetic foot (20) having sensors
(22A, 22B) for use, in cooperation with possible additional sensors (24A, 24B,
26),
with a control system (100) for controlling a prosthesis (14) having an
actuating
mechanism (16). It should be understood that the present invention is not
limited
to the illustrated implementation since various changes and modifications may
be
effected herein without departing from the scope of the appended claims.

Referring therefore to FIG. 1 an individual (10) has a pair of legs (26) and
(28),
one of which, (26), is amputated above the knee. A prosthesis (14) is attached
to
the leg (26) and includes an actuating mechanism (16), which may be either
passive or active. An instrumented prosthetic foot (20) is attached to the
prosthesis (14) and includes sensors (22A, 22B). Additional sensors (24A, 24B)
are located on the healthy foot and additional sensors (26) located on the
individual (10) and/or the prosthesis (14). A passive actuating mechanism may
be
generally defined as an electro-mechanical component that only absorbs
mechanical energy in order to modify dynamics of mechanical joints of the
prosthesis, while an active actuating mechanism may be generally defined as an
electro-mechanical component that absorbs and supplies mechanical energy in
order to set dynamics of mechanical joints of the prosthesis.


CA 02543061 2011-01-27
4

An example of the passive actuating mechanism is described in U.S. Patent No.
6,764,520 issued July 20, 2004, entitled "ELECTRONICALLY CONTROLLED
PROSTHETIC KNEE". Examples of active actuating mechanisms are described
in U.S. Patent No. 7,314,490 issued January 1, 2008, entitled "ACTUATED LEG
PROSTHETIC FOR ABOVE-KNEE AMPUTEES".

The prosthesis (14) is controlled, as shown schematically in FIG. 2, by a
basic
control system (100) comprising sensors (22A, 22B, 24A, 24B, 26), connected
through an interface (30) to a controller (40). The controller (40) provides
signals
to an actuating mechanism (16) in the prosthesis (14) , such as shown in FIG.
1.
The purpose of the control system (100) is to provide the required signals for
controlling the actuating mechanism (16). To do so, the control system (100)
is
interfaced with the amputee (10) using sensors (22A, 22B, 24A, 24B, 26) to
ensure proper coordination between the amputee (10) and the movements of the
prosthesis (14). The sensors (22A, 22B, 24A, 24B, 26) capture information, in
real
time, about the dynamics of the amputee's movement and provide that
information
to the controller (40) via the interface (30). The controller (40) then uses
the
information to determine the resistance to be applied to a joint, in the case
of a
passive actuating mechanism, or the joint trajectories and the required
angular
force or torque that must be applied by a joint, in the case of an active
actuating
mechanism, in order to provide coordinated movements.

The sensors (22A, 22B, 24A, 24B, 26) may include myoelectric sensors, neuro-
sensors, kinematic sensors, kinetic sensors, strain gauges or plantar pressure
sensors. Myoelectric sensors are electrodes used to measure the internal or
the
external myoelectrical activity of skeletal muscles. Neuro-sensors are
electrodes
used to measure the summation of one or more action potentials of peripheral
nerves. Kinematic sensors are used to measure the position of articulated
joints,
the mobility speed or acceleration of lower extremities. Kinetic sensors are
used
to measure angular forces at articulated joints or reaction forces of lower
extremities. Strain gages are used to measure the strain forces at a specific


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underfoot area. Plantar pressure sensors are used to measure the vertical
plantar
pressure of a specific underfoot area. Of course, additional types of sensors
which provide various information about dynamics of human locomotion may be
used. For a given application, the use of sensors (22A, 22B, 24A, 24B, 26) is
not
5 restricted to a specific type of sensor, multiple types of sensors in
various
combinations may be used.

As illustrated in FIG. 1, the sensors (22A, 22B, ) may comprise localized
plantar
pressure sensors located at spaced locations on the prosthetic foot (20) to
measure the vertical plantar pressure of a specific underfoot area. Similarly,
the
plantar pressure sensors (24A, 24B) located on the side of the healthy foot
may be
provided at spaced locations in a custom-made insole, preferably in the form
of a
standard orthopaedic insole, that is modified to embed the two sensors (24A,
24B)
for the measurement of two localized plantar pressures. The sensors (22A, 22B,
24A, 24B) are operable to measure the weight transfer along the foot as the
individual moves which may be combined with other sensors (26) such as
kinematic sensors to measure the angular speed of body segments of the lower
extremities and kinematic sensors to measure the angle of the prosthesis (14)
knee joint.

Each sensor (22A, 22B, 24A, 24B) may comprise a thin Force-Sensing Resistor
(FSR) polymer cell directly connected to the interface (30) of the control
system
(100) or indirectly using an intermediary system (not shown), for instance a
wireless emitter. Of course, other types of communication link technologies
may
be used, such as, for example, optical. The FSR cell has a decreasing
electrical
resistance in response to an increasing force applied perpendicularly to the
surface thereof. Each cell outputs a time variable electrical signal for which
the
intensity is proportional to the total vertical plantar pressure over its
surface area.
The size and position of the plantar pressure sensors (22A, 22B, 24A, 24B) may
be defined in accordance with the stability and the richness (intensity) of
the
localized plantar pressure signals provided by certain underfoot areas during
locomotion. For example, it was found by experimentation that the heel and the
toe regions are two regions of the foot sole where the Plantar Pressure
Maximum


CA 02543061 2011-01-27

6
Variation (PPMV) may be considered as providing a signal that is both stable
and
rich in information.

Accordingly, the controller (40) may use the data signals from the four
localized
plantar pressure sensors (22A, 22B, 24A, 24B), as well as the information
gathered from the data signals of the other sensors (26) such as kinematic
sensors, in order to decompose the locomotion of the individual (10) into a
finite
number of states, and generate the appropriate control signals for controlling
the
actuating mechanism (16) according to the locomotion. Of course, the
controller
(40) is not limited to the use of the preceding data signals.

An example of a controller (40) and control system (100) using sensors
comprising plantar pressure sensors as well as kinematic sensors is described
in
U.S. Patent No. 7,147,667 issued December 12, 2006, entitled "CONTROL
SYSTEM AND METHOD FOR CONTROLLING AN ACTUATED PROSTHESIS".

To facilitate the acquisition of the data in a repeatable and dependable
manner,
the sensors (22A, 22B) are incorporated in to the structure of the foot (20).
An
embodiment of the instrumented prosthetic foot (20) is shown in more detail in
FIGS 3 and 4. The instrumented prosthetic foot (20) includes a foot plate
(53),
forming an elongated body, with a connector (51) at one end, a toe plate (55A)
and a heel plate (55B) that is cantilevered from the foot plate (53). Such an
arrangement is provided by, for example, a Vari-Flex prosthetic foot from
Ossur.
Pressure sensors (22A, 22B) are located at longitudinally spaced locations on
the
underside of the foot plate (53) and heel plate (55) respectively. The sensors
(22A, 22B) are covered by rigid plates (52A, 52B) and resilient pads (54A,
54B).
The pressure sensors (22A, 22B) are located so as to be responsive to loads
imposed on the instrumented prosthetic foot (20) at the regions corresponding
to
the toe area and the heel area respectively.

The rigid plates (52A, 52B) covering the sensors (22A, 22B), although not
essential, help to optimize the pressure distribution on the entire surface of
the


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7
sensors (22A, 22B) as well as inhibiting any shearing and may be made of 85A
durometer polyurethane. Of course, other type of material may be used as well.
The pads (54A, 54B) wrap up the rigid plates (52A, 52B) and the sensors (22A,
22B), forming a ground engaging member, in order to optimize the contact
between the instrumented prosthetic foot (20) and the ground. The pads (54A,
54B) may be made of 40A durometer polyurethane. Of course, other type of
material may be used as well.

In operation, therefore, as the foot (20) traverses the ground, the force
applied to
the heel plate (55B) is measured by the sensor (22B) and a corresponding
signal
forwarded to the controller (40). The force applied to the toe plate (55A) is
also
measured by the sensor (22A) and the relative loading between the two
locations
is measured. As the foot (20) continues to traverse the ground, the force
applied
to the toe area increases and that at the heel decreases to provide a pair of
signals from which the disposition of the leg may be determined and the
appropriate control provided to the actuator (16).

An alternative embodiment of the instrumented prosthetic foot (20) is shown in
FIGS 5 and 6. The instrumented prosthetic foot (20) includes connector (61),
foot
plate (63), toe plate (64A) and heel plate (64B), such as provided by, for
example,
a Vari-Flex prosthetic foot from Ossur. Pressure sensors (22A, 22B) are
located
between the foot plate (63) and rigid plates (62A, 62B). The pressure sensors
(22A, 22B) are located so as to be responsive to load imposed on the
instrumented prosthetic foot (20) at the regions corresponding to the toe area
and
the heel area respectively. More specifically, pressure sensor (22A) is
sandwiched between a pair of rigid plates (62A), which in turn are positioned
between the heel plate (64B) and the foot plate (63). Pressure sensor (22B) is
sandwiched between a pair of rigid plates (62B), which in turn are positioned
between the foot plate (63) and the connector (61).

As for the previous embodiment, rigid plates (62A, 62B) covering the sensors
(22A, 22B), although not essential, help to optimize the pressure distribution
on
the entire surface of the sensors (22A, 22B) as well as inhibiting any
shearing and


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8
may be made of 85A durometer polyurethane. Of course, other type of material
may be used as well.

Another alternative embodiment of the instrumented prosthetic foot (20) is
shown
in FIGS 7 and 8. The instrumented prosthetic foot (20) includes connector
(71),
top foot plate (75), foam cushion core (73) and bottom foot plate (74), such
as
provided by, for example, a LP Talux prosthetic foot from Ossur. Pressure
sensors (22A, 22B) are sandwiched between pairs of rigid plates (72A, 72B).
The
pressure sensors (22A, 22B) are located so as to be responsive to load imposed
on the instrumented prosthetic foot (20) at the regions corresponding to the
toe
area and the heel area respectively. More specifically, pressure sensor (22A)
is
sandwiched between a pair of rigid plates (72A), which in turn are positioned
within gap (76A), which is located between a bottom foot plate (74) and a foam
cushion core (73). Pressure sensor (22B) is sandwiched between a pair of rigid
plates (72B), which in turn are positioned within gap (76B), which is located
within
the foam cushion core (73).

Again, as for the previous embodiments, rigid plates (72A, 72B) covering the
sensors (22A, 22B), although not essential, help to optimize the pressure
distribution on the entire surface of the sensors (22A, 22B) as well as
preventing
any shearing and may be made of 85A durometer polyurethane. Of course, other
type of material may be used as well.

In the previous embodiments, the force (or pressure) at the toe and heel
areas,
F -toe and F_heel respectively, was obtained by positioning pressure sensors
(22A, 22B) directly at those areas. More specifically, referring to FIG. 9, F -
toe
and F -heel were obtained as follows:

F_toe=F_toe_meas Equation I
F_heel = F_heel_meas Equation 2
In other possible embodiments of the instrumented prosthetic foot (20),
sensors
(22A, 22B) may not be restricted to being positioned directly at the toe and
heel


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9
areas, the equivalent information may be obtained by measuring the equivalent
torque at the ankle and the axial force at the connector of the instrumented
prosthetic foot (20). F toe and F -heel may be defined in terms of the torque
measured at the ankle, M_ankle_meas, and the force measured at the connector,
F_conn_mess, using the following equations:

F toe= M_ankle_meas+(F_conn_meas=I_heel) Equation 3
(I _ heel + I _ toe)

F_heel = -M ankle_meas+(F_conn meas. I_toe) Equation 4
(I_heel+l_toe)
where

1 -heel is the distance between the center of the connector and the
center of the heel area;

1 -toe is the distance between the center of the connector and the
center of the toe area.

Following the previous discussion about the locations of sensors (22A, 22B), a
further alternative embodiment of the instrumented prosthetic foot (20) is
shown in
FIGS 10 and 11. The instrumented prosthetic foot (20) includes connector (81),
foot plate (83), toe plate (84A) and heel plate (84B), such as provided by,
for
example, a Vari-Flex prosthetic foot from Ossur, and load cells (22A, 22B).
Load
cells (22A, 22B) are located below connector'(81), load cell (22A) being
slightly
biased towards the toe area of the foot and load cell (22B) being slightly
biased
towards the heel area. Since the sensors (22A, 22B) are not located directly
at
the toe and heel areas, Equation 3 and Equation 4 may be used, for example by
controller (40), to compute the equivalent pressures at the toe and heel areas
by
defining the equivalent torque at the ankle and the axial force at connector
(81) as
follows:

F_conn _meas = F_ 22B +F-22A Equation 5


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M_ankle_measF_22B=I_22B-F_22A=I_22A Equation 6
where

F_22B is the force measured at sensor 22B;
F_22A is the force measured at sensor 22A;

5 1_22B is the distance between the center of the connector (81) and
the center of sensor 22B;

I_22A is the distance between the center of the connector (81) and
the center of sensor 22A.

In the previous embodiments of the instrumented prosthetic foot (20), the
force (or
10 pressure) at the toe and heel areas, F -toe and F_heel respectively, was
obtained
either by positioning pressure sensors (22A, 22B) directly at those areas or
by
positioning pressure sensors or load cells (22A, 22B) in other areas and
obtaining
the equivalent information by computing the equivalent torque at the ankle and
the
axial force at the connector. Other types of sensors may also be used to
obtain
the equivalent torque at the ankle and the axial force at the connector. Such
an
example is illustrated by a further still embodiment of the instrumented
prosthetic
foot (20), which is shown in FIGS 12 and 13. The instrumented prosthetic foot
(20) includes connector (91), mounted on pivoting ankle (93). Bumpers (92A,
92B) are positioned between the pivoting ankle (93) and rocker plate (95)
located
on a foot plate (94). The pivoting ankle (93) is connected to the rocker plate
(95)
by a pivot pin (96). Such an arrangement is provided by, for example, an
Elation
prosthetic foot from Ossur. A load cell (22A) and an optical encoder (22B).
are
incorporated into the foot (20) to provide measurement of the distribution of
forces
along the foot (20). Load cell (22A) is positioned between connector (91) and
pivoting ankle (93). Optical encoder (22B) comprises reader (221) and disk
(223).
Reader (221) is located on pivoting ankle (93) while disk (223) is located on
rocker
plate (95) and encircles pivot pin (96). Once again, Equation 3 and Equation 4
may be used, for example by controller (40), to compute the equivalent
pressures


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11
at the toe and heel areas by defining the equivalent torque at the ankle and
the
axial force at connector (91) as follows:

F_conn_meas = F_22A Equation 7
M_ankle_meas=R_ankle_meas=R_const Equation 8
where

F_22A is the force measured at sensor 22A;

R ankle meas is the rotation measurement of pivoting an kle (93)
about pivot pin (96) as measured by optical encoder (22B);

R const is a constant associated with the resistance of bumpers
(92A, 92B) to compression, which constant varies depending in the
material used.

A yet further alternative embodiment of the instrumented prosthetic foot (20)
is
shown in FIGS 14 and 15. The instrumented prosthetic foot (20) includes
connector (101), mounted on pivoting ankle (103). Bumpers (102A, 102B) are
positioned between the pivoting ankle (103) and rocker plate (105) located on
a
foot plate (104). The pivoting ankle (103) is connected to the rocker plate
(105) by
a pivot pin (106). Such an arrangement is provided by, for example, an Elation

prosthetic foot from Ossur. Pressure sensors (22A, 22B) and load cell (22C)
are
incorporated into the foot (20) to provide measurement of the distribution of
forces
along the foot (20). Pressure sensor (22A) is positioned between rocker plate
(85)
and bumper (82A) while pressure sensor (22B) is positioned between rocker
plate
(85) and bumper (82B). A load cell (22C) is positioned between connector (91)
and pivoting ankle (93).

In this embodiment, Equation 6 is used to compute the equivalent torque at the
ankle, while the axial force at connector (101) is computed using the
following
equation:


CA 02543061 2006-04-19
WO 2005/048887 PCT/CA2003/001802
12
F_conn_meas=F_22C Equation 9

Load cell (22C) is required to compute the axial force at connector (101)
since
when there is no torque at the ankle, i.e. the wearer of the prosthesis is
standing
still, the axial force is being exerted in its entirety onto pivot pin (96).

In all of the described embodiments, the sensors (22A, 22B) may be directly
connected to interface (30) of control system (100) or indirectly using an
intermediary system (not shown), for instance a wireless emitter. Of course,
other
types of communication link technologies may be used, such as, for example,
optical.

Other types of non-articulated or articulated prosthetic foot may be used as
well as
long as the selected prosthetic foot provides approximately the same dynamical
response as the ones mentioned here above. Nevertheless, an articulated foot
offers the best performances. The instrumented prosthetic foot (20) may
further
have an exposed metal or composite structure or it may have a cosmetic
covering
that gives it the appearance of a human ankle and foot.

It should be noted that the present invention is not limited to its use with
the
mechanical configuration illustrated in FIG. 1 or the control system (100)
illustrated
in FIG. 2. It may be used with a leg prosthesis having more than one joint.
For
instance, it may be used with a prosthesis having an ankle joint, a
metatarsophalangeal joint or a hip joint in addition to a knee joint.
Moreover,
instead of a conventional socket a osseo-integrated devices could also be
used,
ensuring a direct attachment between the mechanical component of the
prosthesis
and the amputee skeleton. Other kinds of prostheses may be used as well.

A single figure which represents the drawing illustrating the invention.

For a clearer understanding of the status of the application/patent presented on this page, the site Disclaimer , as well as the definitions for Patent , Administrative Status , Maintenance Fee  and Payment History  should be consulted.

Admin Status

Title Date
Forecasted Issue Date 2012-01-24
(86) PCT Filing Date 2003-11-18
(87) PCT Publication Date 2005-06-02
(85) National Entry 2006-04-19
Examination Requested 2008-10-06
(45) Issued 2012-01-24

Maintenance Fee

Description Date Amount
Last Payment 2018-10-24 $450.00
Next Payment if small entity fee 2019-11-18 $225.00
Next Payment if standard fee 2019-11-18 $450.00

Note : If the full payment has not been received on or before the date indicated, a further fee may be required which may be one of the following

  • the reinstatement fee set out in Item 7 of Schedule II of the Patent Rules;
  • the late payment fee set out in Item 22.1 of Schedule II of the Patent Rules; or
  • the additional fee for late payment set out in Items 31 and 32 of Schedule II of the Patent Rules.

Payment History

Fee Type Anniversary Year Due Date Amount Paid Paid Date
Filing $400.00 2006-04-19
Maintenance Fee - Application - New Act 2 2005-11-18 $100.00 2006-04-19
Registration of Documents $100.00 2006-07-06
Maintenance Fee - Application - New Act 3 2006-11-20 $100.00 2006-10-12
Maintenance Fee - Application - New Act 4 2007-11-19 $100.00 2007-11-19
Request for Examination $800.00 2008-10-06
Maintenance Fee - Application - New Act 5 2008-11-18 $200.00 2008-10-06
Maintenance Fee - Application - New Act 6 2009-11-18 $200.00 2009-10-30
Maintenance Fee - Application - New Act 7 2010-11-18 $200.00 2010-11-18
Reinstatement - failure to respond to examiners report $200.00 2011-01-27
Maintenance Fee - Application - New Act 8 2011-11-18 $200.00 2011-11-08
Final $300.00 2011-11-10
Maintenance Fee - Patent - New Act 9 2012-11-19 $200.00 2012-10-10
Maintenance Fee - Patent - New Act 10 2013-11-18 $250.00 2013-10-09
Maintenance Fee - Patent - New Act 11 2014-11-18 $250.00 2014-10-29
Maintenance Fee - Patent - New Act 12 2015-11-18 $250.00 2015-10-28
Registration of Documents $100.00 2016-03-30
Maintenance Fee - Patent - New Act 13 2016-11-18 $250.00 2016-10-26
Maintenance Fee - Patent - New Act 14 2017-11-20 $250.00 2017-10-25
Registration of Documents $100.00 2018-04-04
Maintenance Fee - Patent - New Act 15 2018-11-19 $450.00 2018-10-24
Current owners on record shown in alphabetical order.
Current Owners on Record
VICTHOM LABORATORY INC.
Past owners on record shown in alphabetical order.
Past Owners on Record
BEDARD, STEPHANE
ROY, PIERRE-OLIVIER
VICTHOM HUMAN BIONICS, INC.
Past Owners that do not appear in the "Owners on Record" listing will appear in other documentation within the application.

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Description 2011-01-27 13 625
Claims 2011-01-27 4 125
Abstract 2006-04-19 2 61
Claims 2006-04-19 3 95
Drawings 2006-04-19 15 229
Description 2006-04-19 12 591
Representative Drawing 2006-04-19 1 13
Cover Page 2006-06-27 2 38
Representative Drawing 2012-01-03 1 13
Cover Page 2012-01-03 1 36
Correspondence 2010-07-27 1 13
Correspondence 2006-06-20 1 26
Correspondence 2010-07-27 1 16
Correspondence 2010-07-22 3 133
PCT 2006-04-19 4 155
Fees 2006-10-12 1 29
Fees 2007-11-19 1 34
Prosecution-Amendment 2008-10-06 1 34
Fees 2008-10-06 1 31
Prosecution-Amendment 2010-07-05 2 75
Fees 2010-11-18 1 66
Prosecution-Amendment 2011-01-27 14 534
Correspondence 2011-11-10 1 65