Takanori Higashihara

Powered orthosis and attachable power-assist device with Hydraulic Bilateral Servo System

This paper discusses the developments and control strategies of exoskeleton-type robot systems for the application of an upper limb powered orthosis and an attachable power-assist device for care-givers. Hydraulic Bilateral Servo System, which consist of a computer controlled motor, parallel connected hydraulic actuators, position sensors, and pressure sensors, are installed in the system to derive the joint motion of the exoskeleton arm. The types of hydraulic component structure and the control strategy are discussed in relation to the design philosophy and target joints motions.

Study of desktop type external shoulder prosthesis control with bilateral servo system

Recent developments in shoulder powered prosthesis control can be divided into two types. The first type, as seen in development at Northwestern University, is depended on a myo-electrical signal replacement surgery in the chest area to allow the control of shoulder rotation, elevation, arm flexion and extension and the opening closing of the hand. On the other hand, our research focuses on using a microcomputer to control pre-developed patterns of the different motions. From our experience in position control of the shoulder prosthesis, this project proposes the need for force control in each of the joints set on the desk. A major concern of the shoulder prosthesis is the need of simultaneously control on its with the consideration of external loads. The external loads on the prosthesis post-installment are significant enough that the position control heavily depends on these external loads. This project proposes our bilateral servo system as a solution for near future desktop type shoulder prosthesis to provide the necessary position and force controlled by myo-electrical command.