Computer controlled hydraulic resistance device for a prosthesis and other apparatus

Abstract

A computer controlled hydraulic resistance device for apparatus such as a prosthetic knee for above knee amputees, includes a two stage pilot operated solenoid valve connected to control the flow of hydraulic fluid to and from a hydraulic actuator which applies resistance to the prosthetic knee or other apparatus through a coupling. Hydraulic pressure is sensed on the high and low side of the actuator by a spring biased magnet and a magnetically actuated electronic sensor and is used by a micro-controller in a closed-loop manner to compensate automatically for variations in the device and in the hydraulic fluid viscosity. The device also has magnetically actuated electronic sensors which sense positions of the apparatus and feed back to the micro-controller for applying a predetermined resistance profile to the apparatus.

Description

RELATED APPLICATION[0001]This application is a continuation-in-part of application Ser. No. 08 / 883,614, Filed Jun. 26, 1997, now U.S. Pat. No. 5,888,212. This application also claims the benefit of prior application Ser. No. 60 / 020,904, Filed Jun. 27, 1996.<?delete-end id="DEL-S-00001" ?> <?insert-start id="INS-S-00001" date="20071225" ?>This application is a continuation of application 10 / 237,571, filed 5 Sep. 2002 (abandoned), which is a reissue of U.S. Pat. No. 6,113,642, issued 5 Sep. 2000, which is a continuation-in-part of application 08 / 883,614, filed 26 Jun. 1997(now U.S. Pat. No. 5,888,212), which claims the benefit of provisional application 60 / 020,904, filed 27 Jun. 1996.<?insert-end id="INS-S-00001" ?>BACKGROUND OF THE INVENTION[0002]The present invention is ideally suited for use with an artificial leg or prosthesis worn by an above knee amputee, but also has other applications and uses. Normally this type of prosthesis involves an artificial knee jo...

AI Technical Summary

Benefits of technology

The present invention is a computer-controlled closed-loop electromechanical resistance device for a lower limb prosthesis. The device can provide swing resistance to a knee unit of a lower limb prosthesis, rehabilitation equipment, exercise equipment, braking devices, or other various damping applications. The device uses a rotary paddle or vane type rotor, which is controlled by a computer to create a variable pressure differential between two sides of the rotor. The control system uses a microprocessor to read the rotor pressure differential, knee position, pressure differential error, and prosthetic force, and calculates the required resistance based on these readings. The control system is adaptive and can compensate for changes in the system operating environment. The device can be used in various applications such as knee control for an above knee amputee, rehabilitation equipment, or exercise equipment.

Problems solved by technology

It has not been feasible to duplicate muscle contraction in leg prosthesis because of the weight and bulk that would be required to duplicate this function.

Mechanical braking mechanisms can be difficult to keep adjusted properly and can cause the amputee to walk with a slightly unnatural gait.

Position activated polycentric mechanisms require more concentration and can be difficult for amputees to use in some situations.

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