Computerized electronic prosthesis apparatus and method

• US 5,413,611 A
• Filed: 07/21/1992
• Issued: 05/09/1995
• Est. Priority Date: 07/21/1992
• Status: Expired due to Fees

• Current Assignee: MCP Services Incorporated
• Original Assignee: MCP Services Incorporated
• Inventors: Tompkins, Michael E., Haslam, Thomas P. II
• Primary Examiner(s): Willse, David H.
• Application Number:
  US07/915,618
• Time in Patent Office: 1,022 Days
• Field of Search: 623/24, 623/25, 623/57, 623/64
• US Class Current: 623/25
• CPC Class Codes: A61F 2/583 Hands; Wrist joints
• CPC Class Codes: A61F 2/586 Fingers
• CPC Class Codes: A61F 2/72 Bioelectric control, e.g. myoelectric
• CPC Class Codes: A61F 2002/587 Thumbs
• 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
• CPC Class Codes: A61F 2002/7635 for measuring force, pressure or mechanical tension

Abstract

A computerized electronic hand prosthesis apparatus and method utilizing input, feedback, control, and operating systems configurable to provide precise control and gripping forces corresponding to the particular capabilities and requirements of an individual wearer. An articulated prosthesis is capable of exerting a mechanical gripping force and contains a programmable microcomputer. Electrodes on the prosthesis contact muscles of the remnant portion of a limb and produce an electric command signal responsive to the myoelectric signal created by the wearer contracting and relaxing the muscles in the remnant portion. A drive motor in the prosthesis causes the prosthesis to exert a mechanical gripping force responsive and proportional to the electric command signal. Force sensors in the digits of the prosthesis detect the force exerted and produce an electric sensor signal responsive and proportional thereto. A motor driven vibratory device on the prosthesis engages the remnant portion of the limb adjacent sensory nerves and produces a feedback signal perceptible to the wearer which changes in vibratory pattern and amplitude at various selective grip forces. A communication port on the prosthesis is releasably connected to peripheral devices for exchanging data, diagnosing, correcting, or setting the operational parameters of the prosthesis. The electrodes, drive motor, force sensors, vibratory device, and communication port are controlled by the microcomputer.

Claims

1. A computerized electronic prosthesis apparatus having selectively configurable operating parameters corresponding to the particular capabilities and requirements of an individual wearer comprising:

an articulated prosthesis adapted to be worn by a living being as a replacement for an amputated limb and capable of exerting a mechanical force;

programmable microcomputer means in said prosthesis connected with a power supply and including a microprocessor, memory, input/output circuitry for receiving signals and producing an output drive signal and an output vibratory signal, signal processing means, drivers, and controllers;

electrode means on said prosthesis operatively connected with said microcomputer and adapted to contact certain muscles of the remnant portion of the limb to produce an electric command signal responsive to a myoelectric signal created by the wearer contracting and relaxing certain muscles in the remnant portion, the threshold voltage points at which said microcomputer will acknowledge a valid electric command signal while eliminating nuisance activations due to movement and environmental noise selectively configured and stored in said microcomputer memory;

drive means in said prosthesis operatively connected with said microcomputer for causing said prosthesis to exert a mechanical force responsive and proportional to said electric command signal, the speed of said drive means and value of said mechanical force exerted by said prosthesis selectively configured relative to the intensity of the myoelectric signal generated by the wearer and stored in said microcomputer memory;

sensor means on said prosthesis operatively connected with said microcomputer for detecting the mechanical force exerted by said prosthesis and producing an electric sensor signal responsive and proportional thereto, the threshold voltage points at which said microcomputer will acknowledge a valid electric sensor signal selectively configured and stored in said microcomputer memory; and

vibratory means on said prosthesis opperatively connected with said microcomputer and adapted to engage the remnant portion of the limb adjacent sensory nerve endings in the skin of the remnant portion of the limb and transmit vibrations which stimulate the nerve endings to produce a feedback signal perceptible to the wearer which is responsive to and indicative of the mechanical force exerted, said vibrations having frequency, amplitude, and modulation characteristics, the operating values of which are selectively configured and stored in said microcomputer memory;

upon said microcomputer receiving a valid said electric command signal, said microcomputer producing an output drive signal to operate said drive means to cause said prosthesis to exert a mechanical force relative to the intensity of the myoelectric signal generated by the wearer, and upon said microcomputer receiving a sensor signal exceeding said threshold voltage points, said microcomputer producing an output vibratory signal causing said vibratory means to transmit vibrations which stimulate the nerve endings to produce feedback signals perceptible to the wearer which are indicative of the mechanical force being exerted; and

said command signal, said drive means, said sensor means, and said vibratory means each being selectively adjustable to compensate for changes in muscle strength, sensitivity, usage, and other conditions affecting operability;

a communication port on said prosthesis operatively connected with said microcomputer and adapted to be releasably connected to peripheral devices for exchanging data, monitoring, diagnosing, adjusting, correcting, or setting the operational parameters of said prosthesis; and

a modem adapted for connection to a telephone and said communications port for data communication between said microcomputer in said prosthesis and a local or remote computer, whereby the wearer can call the manufacturer of said prosthesis, connect said modem into the telephone line and said communication port on said prosthesis, and the manufacturer can then communicate directly with said microcomputer in said prosthesis via telephone to perform diagnostic tests, determine where and if there is a problem or a power failure, and correct problems via the telephone by making corrections to the operating parameters of said prosthesis.

2. A computerized electronic prosthesis apparatus according to claim 1 in which

said microcomputer includes timer means,

said drive means is stopped upon the wearer relaxing a muscle which was contracted sufficiently to terminate the myoelectric signal and the mechanical force exerted by said prosthesis is maintained, and

the value of the mechanical force being exerted by said prosthesis at termination of the myoelectric signal is recorded in said microcomputer memory,

after a preset time delay said microcomputer terminates said feedback signal, and

periodically thereafter, said microcomputer drives said vibratory means to produce an intermittent reminder feedback signal perceptible to the wearer to indicate that the mechanical force is still being exerted.

3. A computerized electronic prosthesis apparatus according to claim 1 in which

said drive means is reversed upon the wearer contracting a muscle to create a myoelectric signal to produce a command signal representing the release of the exerted mechanical force,

said drive means continuing in the reversed mode as long as the myoelectric signal is created by the wearer or until said prosthesis attains a predetermined condition, and

upon termination of the myoelectric signal by the wearer or upon said prosthesis attaining a predetermined condition, said microcomputer terminating the operation of said drive means.

4. A computerized electronic prosthesis apparatus according to claim 1 in which

said prosthesis enters a standby reduced power operational mode upon said microcomputer detecting no electric command signal or no electric sensor signal to minimize current consumption of the system, and

upon detection of an electric command signal, the system immediately returning to a full power operational mode.

5. A computerized electronic prosthesis apparatus according to claim 1 in which

the upper limit value for an amount of voltage gain of said electrode means is selectively configured to facilitate maximum operation of said prosthesis by a wearer having a weak myoelectric signal and stored in said microcomputer memory.

6. A computerized electronic prosthesis apparatus according to claim 1 in which

said drive means is an electric motor and said output drive signal is selectively configured to control the speed of the motor relative to the intensity of the myoelectric signal created by the wearer and stored in said microcomputer memory.

7. A computerized electronic prosthesis apparatus according to claim 6 in which

the maximum speed at which said electric motor causes said prosthesis to exert a mechanical force is selectively configured and stored in said microcomputer memory.

8. A computerized electronic prosthesis apparatus according to claim 6 in which

proportionality of the speed at which said electric motor causes said prosthesis to exert a mechanical force relative to the intensity of the myoelectric signal created by the wearer is selectively configured and stored in said microcomputer memory.

9. A computerized electronic prosthesis apparatus according to claim 6 in which

the maximum speed at which said electric motor is turned on or off upon the myoelectric command signal going above or below the configured threshold voltage points is selectively configured and stored in said microcomputer memory.

10. A computerized electronic prosthesis apparatus according to claim 6 including

a motor stall detection program stored in said microcomputer memory which monitors and analyzes the range of voltage generated by said electric motor during a drive on mode and the back electromotive force of said electric motor during a drive off mode, linearizes the data, and interprets the data relative to the mechanical force exerted by said prosthesis.

11. A computerized electronic prosthesis apparatus according to claim 1 in which

the main frequency of said vibrations is set at a frequency to allow maximum penetration through the skin to nerve endings and reduce the amount of power consumed,

the modulation of said vibrations is linearly proportional to the electric sensor signal produced by said sensor means to represent the mechanical forces exerted by said prosthesis, and

the vibratory pattern and amplitude of said output vibratory signal being selectively configured corresponding to various mechanical force values exerted by said prosthesis and stored in said microcomputer memory, whereby

the vibratory pattern and amplitude of said output vibratory signal changes at various predetermined mechanical force values exerted by said prosthesis.

12. A computerized electronic prosthesis apparatus according to claim 1 including

a force loss detection and correction program stored in said microcomputer memory which monitors and analyzes the mechanical force being exerted by said prosthesis and upon determination that the exerted force is being reduced will activate said drive means to regain but not exceed the force originally established by said electric command signal,

the activation of said drive means to regain the force originally established being independent of myoelectric signals created by the wearer, such that

said prosthesis is capable of automatically detecting and compensating for loss of mechanical force without any action on the part of the wearer.

13. A computerized electronic prosthesis apparatus according to claim 1 including

a diagnostics program stored in said microcomputer memory and invoked upon power being supplied at start up which performs internal diagnostic tests to check the status and condition of the operating components and memory devices, record any detected abnormalities in memory for later retrieval, and to correct any abnormalities where possible.

14. A computerized electronic prosthesis apparatus according to claim 1 including

a security program stored in said microcomputer memory which monitors and detects any unauthorized attempt to read, evaluate, or remove the system programs, and upon detection thereof to provide only the manufacturer'"'"'s name, copyright notification, and a security message.

21. The method according to claim 12 including the steps of;

setting the maximum speed at which said electric motor is turned on or off upon the electric command signal going above or below the set threshold voltage points and storing the setting in microcomputer memory.

15. A method of controlling the operation of an electronic prosthesis apparatus relative to the particular capabilities and requirements of a particular wearer and providing feedback signals to the wearer relative to the prosthesis operation comprising the steps of:

providing an articulated prosthesis to be worn by a living being as a replacement for an amputated limb and capable of exerting a mechanical force, said prosthesis including programmable microcomputer means connected with a power supply and having a microprocessor, memory, input/output circuitry for receiving signals and producing an output drive signal and an output vibratory signal, signal processing means, drivers, and controllers;

providing electrode means on said prosthesis operatively connected with said microcomputer which contact certain muscles of the remnant portion of the limb to produce an electric command signal responsive to a myoelectric signal created by the wearer contracting and relaxing certain muscles in the remnant portion;

setting threshold voltage points at which said microcomputer will acknowledge a valid electric command signal while eliminating nuisance activations due to movement or environmental noise and storing the setting in said microcomputer memory;

providing drive means in said prosthesis operatively connected with said microcomputer for causing said prosthesis to exert a mechanical force responsive and proportional to said electric command signal;

setting the speed of said drive means and the value of said mechanical force exerted by said prosthesis relative to the intensity of the myoelectric signal generated by the wearer and storing the setting in said microcomputer memory;

providing sensor means on said prosthesis operatively connected with said microcomputer for detecting the mechanical force exerted by said prosthesis and producing an electric sensor signal responsive and proportional thereto;

setting the threshold voltage points at which said microcomputer will acknowledge a valid electric sensor signal and storing the setting in said microcomputer memory;

providing vibratory means on said prosthesis operatively connected with said microcomputer and adapted to engage the remnant portion of the limb adjacent sensory nerve endings in the skin of the remnant portion and transmit vibrations having frequency, amplitude, and modulation characteristics which stimulate the nerve endings to produce a feedback signal perceptible to the wearer which is responsive to and indicative of the mechanical force exerted;

setting the operating values of the frequency, amplitude, and modulation characteristics of said vibrations and storing the operating values in said microcomputer memory;

configuring said microcomputer to receive said electric command signal and, responsive to a valid electric command signal, to produce an output drive signal to operate said drive means to cause said prosthesis to exert a mechanical force relative to the intensity of the myoelectric signal generated by the wearer;

configuring said microcomputer to receive and monitor said sensor signal and upon said sensor signal exceeding said threshold voltage points to produce an output vibratory signal to cause said vibratory means to transmit vibrations such that upon said microcomputer receiving a valid said electric command signal, said microcomputer produces an output drive signal to operate said drive means to cause said prosthesis to exert a mechanical force relative to the intensity of the myoelectric signal generated by the wearer, and upon said microcomputer receiving a sensor signal exceeding said threshold voltage points, said microcomputer produces an output vibratory signal causing said vibratory means to transmit vibrations which stimulate the nerve endings to produce feedback signals perceptible to the wearer which are indicative of the mechanical force being exerted;

providing a communication port on said prosthesis operatively connected with said microcomputer and adapted to be releasably connected to peripheral devices for exchanging data, monitoring, diagnosing, adjusting, correcting, or setting the operational parameters of said prosthesis;

providing for a modem adapted for connection to a telephone and said communications port for data communication between said microcomputer in said prosthesis and a local or remote computer, whereby the wearer can call the manufacturer of said prosthesis, connect said modem into the telephone line and said communication port on said prosthesis, and the manufacturer can then communicate directly with said microcomputer in said prosthesis via telephone to perform diagnostic tests, determine where and if there is a problem or a power failure, and correct problems via the telephone by making corrections to the operating parameters of said prosthesis.

16. The method according to claim 15 including the steps of:

providing a communication port on said prosthesis operatively connected with said microcomputer; and

releasably connecting said communication port to peripheral devices, and

exchanging data, monitoring, diagnosing, adjusting, correcting, and setting the operational parameters of said prosthesis as necessary to facilitate maximum operation of said prosthesis.

17. The method according to claim 15 including the steps of:

setting the upper limit value for an amount of voltage gain of said electrode means to facilitate maximum operation of said prosthesis by a wearer having a weak myoelectric signal and storing the setting in said microcomputer memory.

18. The method according to claim 15 in which

said drive means is an electric motor, and including the step of;

setting said output drive signal to control the speed of the motor relative to the intensity of the myoelectric signal created by the wearer and storing the setting in said microcomputer memory.

19. The method according to claim 18 including the step of;

setting the maximum speed at which said electric motor causes said prosthesis to exert a mechanical force and storing the setting in said microcomputer memory.

20. The method according to claim 18 including the step of;

setting the proportionality of the speed at which said electric motor causes said prosthesis to exert a mechanical force relative to the intensity of the myoelectric signal created by the wearer and storing the setting in said microcomputer memory.

22. The method according to claim 16 including the steps of;

electronically monitoring and analyzing the range of voltage generated by said electric motor during a drive on mode and the back electromotive force of said electric motor during a drive off mode, linearizing the data, and interpreting the data relative to the mechanical force exerted by said prosthesis

23. The method according to claim 15 in which

the main frequency of said vibrations is set at a frequency to allow maximum penetration through the skin to nerve endings and reduce the amount of power consumed,

the modulation of said vibrations is set to be linearly proportional to the electric sensor signal produced by said sensor means to represent the mechanical forces exerted by said prosthesis, and

the vibratory pattern and amplitude of the output vibratory signal is set at predetermined values corresponding to various mechanical force values such that as the mechanical force exerted by the prosthesis changes, the vibratory pattern and amplitude of said vibrations change corresponding to the set mechanical force values.

24. The method according to claim 15 including the step of

electronically monitoring and analyzing the mechanical force being exerted by said prosthesis and, upon determination that the exerted force is being reduced, activating said drive means to regain but not exceed the force originally established by said electric command signal,

the activation of said drive means to regain the force originally established being independent of myoelectric signals created by the wearer, such that

said prosthesis is capable of automatically detecting and compensating for loss of mechanical force without any action on the part of the wearer.

25. The method according to claim 15 including the steps of

storing a diagnostics program in said microcomputer memory, and

invoking said diagnostics program upon power being supplied at start up to perform internal diagnostic tests to check the status and condition of the operating components and memory devices, record any detected abnormalities in memory for later retrieval, and to correct any abnormalities where possible.

26. The method according to claim 15 including the steps of

storing a security program in said microcomputer memory,

invoking said security program upon power being supplied at start up, and

electronically monitoring and detecting any unauthorized attempt to read, evaluate, or remove the system programs, and upon detection thereof causing said microcomputer to provide only find the manufacturer'"'"'s name, copyright notification, and a security message.