STAIR ASCENT AND DESCENT CONTROL FOR POWERED LOWER LIMB DEVICES

• US 20130310949A1
• Filed: 03/15/2013
• Published: 11/21/2013
• Est. Priority Date: 05/15/2012
• Status: Active Grant

• Current Assignee: Vanderbilt University
• Original Assignee: Vanderbilt University
• Inventors: Goldfarb, Michael, Lawson, Brian, Varol, Atakan Huseyin
• Granted Patent: US 10,441,439 B2
• Time in Patent Office: Days
• US Class Current: 623/27
• CPC Class Codes: A61F 2/60 Artificial legs or feet or parts thereof
• CPC Class Codes: A61F 2/64 Knee joints
• CPC Class Codes: A61F 2/6607 Ankle joints
• CPC Class Codes: A61F 2/70 electrical
• CPC Class Codes: A61F 2002/607 Lower legs
• CPC Class Codes: A61F 2002/701 operated by electrically controlled means, e.g. solenoids or torque motors
• CPC Class Codes: A61F 2002/704 computer-controlled, e.g. robotic control
• CPC Class Codes: A61F 2002/7625 for measuring angular position
• CPC Class Codes: A61F 2002/7635 for measuring force, pressure or mechanical tension

Abstract

Systems and methods of operating a lower limb device having at least a powered joint are provided. A method includes configuring the device to a first state in a finite state model for a current activity mode including a stair ascent mode or a stair descent mode. The method also includes, based on real-time sensor information, transitioning the device between different states in the finite state model when pre-defined criteria for transitioning among the different states are met. In the method, the finite state model for stair ascent includes lifting and swing phases, where the lifting phase includes a powered knee extension and a powered ankle push-off. The finite state model for stair descent includes yielding and swing states, where the swing states include providing a powered plantarflexion of the powered ankle joint and the yielding states include providing a resistive and passive plantarflexion of the powered ankle joint.

Claims

1. A method of operating a lower limb device comprising a powered knee joint and a powered ankle joint, the method comprising:

configuring the lower limb device to a state of a finite state model for a current activity mode comprising a stair ascent mode;

based on real-time sensor information for the lower limb device, transitioning the lower limb device from a current state to a subsequent state in the finite state model when a pre-defined criteria for transitioning to the subsequent state is met; and

repeating the transitioning until the current activity mode changes,

wherein the finite state model for the stair ascent mode comprises a series of states, the series of states comprising at least one lifting state and at least one swing state, wherein the at least one lifting state comprises a powered knee extension and a powered ankle push-off.

2. The method of claim 1, wherein the at least one lifting state comprise a powered knee straightening state and an ankle push off portion state, and wherein the at least one swing state comprises a knee flexion state and a knee extension state.

3. The method of claim 1, wherein the transitioning between the at least one lifting state and at least one swing state is based on at least a measurement of load in the lower limb device.

4. The method of claim 1, further comprising selecting the current activity mode to be the stair ascent mode when an estimate of an orientation with respect to gravity for a thigh associated with the powered knee joint indicates hip extension for a period of time.

5. The method of claim 1, further comprising selecting to exit the stair ascent mode when an estimate of an orientation with respect to gravity for a thigh associated with the powered knee joint indicates an absence of hip flexion for a period of time.

6. The method of claim 1, further comprising selecting to change the current activity mode to or from the stair ascent mode based on a measurement of at least one of a stance time, a swing time, or a stride time.

7. A method of operating a lower limb device comprising at least a powered ankle joint, the method comprising:

configuring the lower limb device to a state in a finite state model for a current activity mode comprising a stair descent mode;

based on real-time sensor information for the lower limb device, transitioning the lower limb device from a current state to a subsequent state in the finite state model when a pre-defined criteria for transitioning to the subsequent state is met; and

repeating the transitioning until the current activity mode changes,

wherein the finite state model for the stair descent mode comprises a series of states, the series of states comprising at least one yielding state and at least one swing state, wherein the at least one swing state comprises providing a powered plantarflexion of the powered ankle joint, and wherein the at least one yielding state comprises providing a resistive and passive plantarflexion of the powered ankle joint.

8. The method of claim 7, wherein the lower limb device further comprises a powered knee joint, and wherein at least one yielding state further comprises providing a resistive and passive flexion of the powered knee joint.

9. The method of claim 7, wherein the at least one yielding state comprises an ankle dorsiflexion state and a knee flexion state, and wherein the at least one swing state comprises a knee flexion state and a knee extension state.

10. The method of claim 7, wherein the transitioning between the at least one yielding state and the at least one swing state is based on at least a measurement of load in the lower limb device.

11. The method of claim 7, wherein the transitioning between at least one yielding state and the at least one swing state is based on at least a measure of ankle angle.

12. The method of claim 7, further comprising:

selecting the current activity mode to be the stair descent mode when an estimate of the orientation of the user'"'"'s thigh with respect to gravity indicates hip flexion for a period of time, and

selecting to exit the stair descent mode when an estimate of the orientation with respect to gravity for a thigh associated with the powered knee joint indicates the absence of hip flexion for a period of time.

13. The method of claim 8, further comprising selecting to change the current activity mode to or from the stair descent mode based on a measurement of at least one of a stance time, a swing time, or a stride time.

14. A computer-readable medium comprising a plurality of instructions for causing a controller device for a lower limb device to perform the method comprising:

configuring the lower limb device to a state of a finite state model for a current activity mode comprising a stair ascent mode;

based on real-time sensor information for the lower limb device, transitioning the lower limb device from a current state to a subsequent state in the finite state model when a pre-defined criteria for transitioning to the subsequent state is met; and

repeating the transitioning until the current activity mode changes,

wherein the finite state model for the stair ascent mode comprises a series of states, the series of states comprising at least one lifting state and at least one swing state, wherein the at least one lifting state comprises a powered knee extension and a powered ankle push-off.

15. A computer-readable medium comprising a plurality of instructions for causing a controller device for a lower limb device to perform the method comprising:

configuring the lower limb device to a state in a finite state model for a current activity mode comprising a stair descent mode;

based on real-time sensor information for the lower limb device, transitioning the lower limb device from a current state to a subsequent state in the finite state model when a pre-defined criteria for transitioning to the subsequent state is met; and

repeating the transitioning until the current activity mode changes,

wherein the finite state model for the stair descent mode comprises a series of states, the series of states comprising at least one yielding state and at least one swing state, wherein the at least one swing state comprises providing a powered plantarflexion of the powered ankle joint, and wherein the at least one yielding state comprises providing a resistive and passive plantarflexion of the powered ankle joint.

16. A lower limb device comprising at least one of a powered knee joint and a powered ankle joint, comprising:

at least one sensor for generating real-time sensor information for the lower limb device;

at least one processor communicatively coupled to the at least one sensor, the powered knee joint and the powered ankle joint; and

a computer-readable medium, having stored thereon instructions for causing the at least one processor to perform the method comprising;

configuring the lower limb device to a state of a finite state model for a current activity mode comprising a stair ascent mode;

based on real-time sensor information for the lower limb device, transitioning the lower limb device from a current state to a subsequent state in the finite state model when a pre-defined criteria for transitioning to the subsequent state is met; and

repeating the transitioning until the current activity mode changes,

wherein the finite state model for the stair ascent mode comprises a series of states, the series of states comprising at least one lifting state and at least one swing state, wherein the at least one lifting state comprises a powered knee extension and a powered ankle push-off.

17. A lower limb device comprising at least one of a powered knee joint and a powered ankle joint, comprising:

at least one sensor for generating real-time sensor information for the lower limb device;

at least one processor communicatively coupled to the at least one sensor, the powered knee joint and the powered ankle joint; and

a computer-readable medium, having stored thereon instructions for causing the at least one processor to perform the method comprising;

configuring the lower limb device to a state in a finite state model for a current activity mode comprising a stair descent mode;

based on real-time sensor information for the lower limb device, transitioning the lower limb device from a current state to a subsequent state in the finite state model when a pre-defined criteria for transitioning to the subsequent state is met; and

repeating the transitioning until the current activity mode changes,

wherein the finite state model for the stair descent mode comprises a series of states, the series of states comprising at least one yielding state and at least one swing state, wherein the at least one swing state comprises providing a powered plantarflexion of the powered ankle joint, and wherein the at least one yielding state comprises providing a resistive and passive plantarflexion of the powered ankle joint.