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.

Abstract: A biomechanical feedback arrangement wherein a varying force tending to improve the neuromotor tracking response of a human subject, particularly in the presence of lateral or front-back G force fields, is added to the test subject input member of a feedback control system. Use of the biomechanical feedback in a high-performance aircraft and in a ground-based simulator apparatus is also disclosed, along with comparison results from simulator testing of human subjects.

Abstract: This invention relates to the hydraulic control field wherein an electronic controller provides the necessary electrical elements for controlling the movement of an actuator shaft from one pre-selected position to another pre-selected position at a pre-selected velocity and provided with an automatic timing control circuit to sustain the movement or a manual operation to selectively move the actuator. The pre-selected positions and velocities are adjustable over the full range of actuator movement and velocity limit of the hydraulics.

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.