BIOMIMETIC CONTROLLER FOR INCREASED DEXTERITY PROSTHESIS

• US 20140128992A1
• Filed: 11/08/2013
• Published: 05/08/2014
• Est. Priority Date: 11/08/2012
• Status: Active Grant

• Current Assignee: University of Akron
• Original Assignee: University of Akron
• Inventors: Engeberg, Erik
• Granted Patent: US 10,543,111 B2
• Time in Patent Office: Days
• US Class Current: 623/25
• CPC Class Codes: A61F 2/583 Hands; Wrist joints
• CPC Class Codes: A61F 2/68 Operating or control means
• CPC Class Codes: A61F 2/70 electrical
• CPC Class Codes: A61F 2/72 Bioelectric control, e.g. myoelectric
• CPC Class Codes: B25J 9/1612 characterised by the hand, wrist, grip control

Abstract

A sliding mode biomimetic (BSM) controller for a prosthetic device, such as a prosthetic hand, includes an input classification component that receives electromyogram (EGM) signals from two or more electromyogram (EGM) sensors that are positioned on an amputee'"'"'s body. The input classification component compares the EGM input signals based on predetermined activation threshold values and identifies an input class to determine the amputee'"'"'s intended movement of the prosthetic device. A finite state machine utilizes the current position of the prosthetic hand and the identified input class to identify the coordinates of a lookup table to determine the next state or position of the prosthetic device. As a result, the biomimetic controller is able to simultaneously control two or more degrees of freedom (DOFs) or functions of the prosthetic hand using only two EGM input signals.

Claims

1. A control system for a prosthetic device having at least two degrees of freedom, the control system comprising:

a controller adapted to be coupled to the prosthetic device, and adapted to receive at least two electromyogram (EMG) signals, each signal being from different muscle groups of an individual, said controller configured to compute a first motion control signal and a second motion control signal, such that said first motion control signal is a scaled sum of the at least two EMG signals, and said second motion control signal is a scaled difference of the at least two EMG signals;

wherein said first motion control signal and said second motion control signal simultaneously control the at least two degrees of freedom of the prosthetic device.

2. The control system of claim 1, wherein the prosthetic device comprises a hand.

3. The control system of claim 2, wherein the at least two degrees of freedom comprise wrist flexion/extension and grip force.

4. A method for controlling a prosthetic device having at least two degrees of freedom comprising:

providing a controller adapted to be interfaced with the prosthetic device;

receiving at least two electromyogram (EMG) signals from different muscles of an individual at said controller;

generating a first motion control signal defined as a scaled sum of the at least two EMG signals;

generating a second motion control signal defined as a scaled difference of the at least two EMG signals; and

controlling the prosthetic device using said first and second motion control signals to simultaneously control the at least two degrees of freedom.

5. The control system of claim 4, wherein the prosthetic device comprises a hand.

6. The control system of claim 5, wherein the at least two degrees of freedom comprise wrist flexion/extension and grip force.

7. A method for controlling a prosthetic device having at least two degrees of freedom comprising:

providing a control system adapted to be coupled to a control interface of the prosthetic device, said control system including a first electromyography (EMG) sensor and a second electromyography (EMG) sensor that are adapted to be attached to the skin of the user to detect muscle contractions, said control system storing a first and a second activation threshold value, and a lookup table of a plurality of actuation positions of the prosthetic device that are each identified by an initial position of the prosthetic hand and one or more predetermined input classes;

detecting a first electromyography signal at said first EMG sensor, and detecting a second electromyography signal at said second EMG sensor;

comparing the magnitude of said first and second EMG signals to each of said first and second activation threshold values;

identifying the input class based on said comparison step;

determining said actuation position from said lookup table based on said identified input class and said initial position of the prosthetic device; and

simultaneously controlling at least two degrees of freedom, so as to move the prosthetic device to said actuation position.

8. The method of claim 7, wherein the prosthetic device comprises a hand.

9. The method of claim 8, wherein the at least two degrees of freedom comprise wrist flexion/extension and grip force.