Control system for prosthetic devices

• US 5,376,128 A
• Filed: 08/31/1992
• Issued: 12/27/1994
• Est. Priority Date: 08/31/1992
• Status: Expired due to Fees

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Bozeman, Richard J. Jr.
• Primary Examiner(s): Willse, David H.
• Application Number:
  US07/937,325
• Time in Patent Office: 848 Days
• Field of Search: 623/24, 623/25, 623/58, 623/63, 623/64, 623/62, 623/60
• US Class Current: 623/24
• CPC Class Codes: A61B 5/1121 Determining geometric values, e.g. centre of rotation or angular range of movement
• CPC Class Codes: A61B 5/1125 Grasping motions of hands
• CPC Class Codes: A61B 5/4528 Joints A61B5/4533, A61B5/4538 take precedence
• CPC Class Codes: A61F 2/585 Wrist joints
• CPC Class Codes: A61F 2/586 Fingers
• CPC Class Codes: A61F 2/72 Bioelectric control, e.g. myoelectric
• CPC Class Codes: A61F 2002/704 computer-controlled, e.g. robotic control

Abstract

A control system and method for prosthetic devices is provided. The control system comprises a transducer for receiving movement from a body part for generating a sensing signal associated with that movement. The sensing signal is processed by a linearizer for linearizing the sensing signal to be a linear function of the magnitude of the distance moved by the body part. The linearized sensing signal is normalized to be a function of the entire range of body part movement from the no-shrug position of the moveable body part through the full-shrug position of the moveable body part. The normalized signal is divided into a plurality of discrete command signals. The discrete command signals are used by typical converter devices which are in operational association with the prosthetic device. The converter device uses the discrete command signals for driving the moveable portions of the prosthetic device and its sub-prosthesis. The method for controlling a prosthetic device associated with the present invention comprises the steps of receiving the movement from the body part, generating a sensing signal in association with the movement of the body part, linearizing the sensing signal to be a linear function of the magnitude of the distance moved by the body part, normalizing the linear signal to be a function of the entire range of the body part movement, dividing the normalized signal into a plurality of discrete command signals, and implementing the plurality of discrete command signals for driving the respective moveable prosthesis device and its sub-prosthesis.

Claims

1. A control system for use with a prosthetic device, the prosthetic device comprising a plurality of moveable sub-prostheses and incorporating any implementation of the well known harness and shoulder control hardware such that the conventional shoulder shrug control movement associated with a moveable body part ranging from the no-shrug position of the moveable body part through the full-shrug position of the moveable body part provides control by the user to the prosthetic device, the control system comprising:

(a) transducer means for generating at Least one sensing signal in consonance with the movement of the body part,

(b) a linearizer configured to receive the sensing signal from said transducer means and to linearize the sensing signal to be a linear function of the magnitude of the distance moved by the body part,

(c) a normalizer operatively associated with said linearizer for receiving the linear signal from said linearizer and for normalizing the linear signal to be a function of the entire range of body part movement from the no-shrug position of the moveable body part through the full-shrug position of the moveable body part,

(d) a discriminator configured to receive the normalized signal from said normalizer for dividing the normalized signal into a plurality of discrete command signals, and

(e) a converter in operational association with the prosthetic device to receive the discrete command signals from said discriminator and to couple each of said discrete command signals to drive means to drive a different one of said plurality of moveable sub-prostheses of the prosthetic device.

2. A control system for use with a prosthetic device as defined in claim 1 wherein said discriminator for dividing the normalized signal into a plurality of discrete command signals further comprises means for providing sustained linear commands.

3. A control system for use with a prosthetic device as defined in claim 2 wherein the sustained linear commands are sequential.

4. A control system for use with a prosthetic device as defined in claim 2 wherein the sustained linear commands are non-sequential.

5. A control system for use with a prosthetic device as defined in claim 1 wherein said discriminator for dividing the normalized signal into a plurality of discrete command signals further comprises means for providing unsustained linear commands.

6. A control system for use with a prosthetic device as defined in claim 5 wherein the unsustained linear commands are sequential.

7. A control system for use with a prosthetic device as defined in claim 5 wherein the unsustained linear commands are non-sequential.

8. A control system for use with a prosthetic device as defined in claim 1 wherein said discriminator for dividing the normalized signal into a plurality of discrete command signals further comprises means for providing sustained logarithmic commands.

9. A control system for use with a prosthetic device as defined in claim 8 wherein the sustained logarithmic commands are sequential.

10. A control system for use with a prosthetic device as defined in claim 8 wherein the sustained logarithmic commands are non-sequential.

11. A control system for use with a prosthetic device as defined in claim 1 wherein said discriminator for dividing the normalized signal into a plurality of discrete command signals further comprises means for providing unsustained logarithmic commands.

12. A control system for use with a prosthetic device as defined in claim 11 wherein the unsustained logarithmic commands are sequential.

13. A control system for use with a prosthetic device as defined in claim 11 wherein the unsustained logarithmic commands are non-sequential.