Tactile stimulus receptor for a hand prosthesis

• US 4,808,187 A
• Filed: 10/05/1987
• Issued: 02/28/1989
• Est. Priority Date: 10/05/1987
• Status: Expired due to Fees

• Current Assignee: Iowa State University Research Foundation Incorporated (Iowa State University)
• Original Assignee: Iowa State University Research Foundation Incorporated (Iowa State University)
• Inventors: Katz, Judd A., Patterson, Patrick E.
• Primary Examiner(s): FRINKS, RONALD
• Application Number:
  US07/104,067
• Time in Patent Office: 512 Days
• Field of Search: 623/24, 623/25, 623/26, 623/63, 623/64
• US Class Current: 623/25
• CPC Class Codes: A61F 2/588 Hands having holding devices shaped differently from human fingers, e.g. claws, hooks, tubes
• CPC Class Codes: A61F 2/72 Bioelectric control, e.g. myoelectric
• CPC Class Codes: A61F 2/74 fluid , i.e. hydraulic or pneumatic
• CPC Class Codes: A61F 2/741 using powered actuators, e.g. stepper motors or solenoids
• CPC Class Codes: A61F 2002/6827 Feedback system for providing user sensation, e.g. by force, contact or position
• CPC Class Codes: A61F 2002/704 computer-controlled, e.g. robotic control

Abstract

A means and method for tactile stimulus reception for use with a myoelectric prosthesis includes a pressure transducer positioned on the prosthesis. The pressure transducer senses the level of pressure experienced by the gripping portion of the prosthesis and converts the sensed pressure into a corresponding signal. A pressure stimulus member is positionable upon the user and creates a pressure stimulus proportionally corresponding to the sensed pressure of the pressure transducer by utilizing the signal from the pressure transducer. The pressure stimulus is tactile so that the user can be given direct tactile pressure stimulation corresponding directly with the pressure sensed by the pressure transducer.

Claims

1. A tactile stimulus receptor for use with a myoelectric prosthesis comprising:

pressure transducer means positioned on the prosthesis for sensing pressure experienced by gripping of an object by the prosthesis, and converting the sensed pressure into a corresponding signal, the pressure transducer means comprising a piezoelectric means which creates electronic impulses proportional to pressure experienced;

pressure stimulus means adapted to be operatively positioned on a user for producing a pressure stimulus corresponding to the pressure sensed by the pressure transducer means, the pressure stimulus means comprising a tactile pressure means adapted to be placed in abutment with the user, and variable pressure generating means operatively connected to the pressure transducer means for producing a variable tactile pressure stimulus proportional to pressure sensed by the pressure transducer means, the tactile pressure means comprising a hydraulically pressurizable cuff member which substantially encircles and abuts the user'"'"'s truncated limb, the cuff member being variably pressurized.

2. The means of claim 1 wherein the piezoelectric means comprises a piezoelectric film.

3. A tactile stimulus receptor for use with a myoelectric prosthesis comprising:

pressure transducer means positioned on the prosthesis for sensing pressure experienced by gripping of an object by the prosthesis, and converting the sensed pressure into a corresponding signal; and

pressure stimulus means adapted to be operatively positioned on a user for providing a pressure stimulus corresponding to the pressure sensed by the pressure transducer means, the pressure stimulus means comprising a tactile pressure means adapted to be placed in abutment with the user, and variable pressure generating means operatively connected to the pressure transducer means for producing a variable tactile pressure stimulus proportional to pressure sensed by the pressure transducer means, the variable pressure generating means comprising a motor which operates a hydraulic cylinder to produce variable hydraulic pressure according to the operation of the motor.

4. The means of claim 3 wherein the motor comprises a stepper motor which is reversible so as to operate to increase and decrease pressure in the hydraulic cylinder according to instruction.

5. The means of claim 4 wherein the pressure stimulus means further includes an electrical control circuitry means.

6. The means of claim 5 wherein the electrical control circuitry includes a Schmidtt trigger to detect signal polarity for determining the direction in which the stepper motor will turn.

7. The means of claim 5 wherein the electrical control circuitry includes a signal control means which automatically reduces the signal to the pressure stimulus means when no pressure changes are detected so that no pressure stimulus changes are affected.

8. A tactile stimulus receptor for use with a myoelectric prosthesis comprising:

pressure transducer means positioned on the prosthesis for sensing pressure experienced by gripping of an object by the prosthesis, and converting the sensed pressure into a corresponding signal; and

pressure stimulus means adapted to be operatively positioned on a user for producing a pressure stimulus corresponding to the pressure sensed by the pressure transducer means, the pressure stimulus means including an electrical control circuitry means which in turn includes a noise reduction electrical circuitry means for reducing common mode pick-up noise.

9. The means of claim 8 wherein the electrical control circuitry includes a band pass filter for reducing the effects of temperature and low frequency noise.

10. A tactile stimulus receptor for use with a myoelectric prosthesis comprising:

pressure transducer means positioned on the prosthesis for sensing pressure experienced by gripping of an object by the prosthesis, and converting the sensed pressure into a corresponding signal;

pressure stimulus means adapted to be operatively positioned on a user for producing a pressure stimulus corresponding to the pressure sensed by the pressure transducer means;

the pressure stimulus means further including an electrical control circuitry means which includes a signal control means which automatically reduces the signal to the pressure stimulus means when no pressure changes are detected so that no pressure stimulus are affected.

11. The prosthesis device including a tactile stimulus receptor to allow, precise and accurate control of the prosthesis device comprising:

a myoelectrically controlled artificial hand means;

pressure transducer means for position on the myoelectrically controlled artificial hand for sensing pressure experienced by gripping of an object by the artificial hand; and

converting the sensed pressure into a corresponding signal, the pressure means comprising a piezoelectric means which creates electronic pulses proportional to pressure experienced;

pressure stimulus means adapted to be operatively positioned on a user for producing a pressure stimulus corresponding to the pressure sensed by the pressure transducer means the pressure stimulus means comprising a hydraulically pressurizable cuff means adaptable to be positioned around the user'"'"'s truncated limb and a hydraulic cylinder for producing variable hydraulic pressure in response to operation of a motor, which in turn operates in response to the electronic impulses from the piezoelectric means to produce constriction proportional to the release of pressure sensed at the pressure transducer means.

12. A method for tactile stimulus reception for use with a myoelectric prosthesis, comprising the steps of:

positioning a pressure transducer means comprising a piezoelectric film means on the prosthesis for sensing pressure experienced by gripping an object by the prosthesis and converting the sensed pressure into a corresponding electrical signal proportional to pressure experienced; and

positioning a hydraulically pressurizable cuff means on the truncated limb of a user;

utilizing the electrical signals from the pressure transducer means to operate a hydraulic cylinder means to create hydraulic pressure in the cuff means proportional to the pressure experienced at the pressure transducer means, causing the cuff means to constrict the truncated limb, reduce constriction onthe truncated limb, or remain at a certain constriction level according to the pressures experienced at the pressure transducer means, the cuff means producing a precise, accurate sensory stimulus to allow precise and accurate control of the artificial hand.

13. The method of claim 12 comprising the further step of reducing electrical noise to reduce interference with the accurate operation of the artificial hand.

14. The method claim 12 further comprising the step of reducing the effects of temperature to operation of the artificial hand, by including electrical circuitry to suppress the effects of temperature.

15. The method of claim 12 further comprising the step of producing a signal which automatially reduces hydraulic pressure to the cuff means when no pressure changes are detected by the pressure transducer means.