project specification

Simple-structured Pneumatic Robot Arm

A flexible robot arm applied into a rehabilitation device for the human wrist. This robot arm has three degree-of-freedom that is bending, expanding and contracting. When the robot arm is applied to a rehabilitation device, two kinds of control method are needed. One is a masterslave control, and the other is a trajectory control. The master-slave control is necessary when a physical therapist wants to give a rehabilitation motion to a patient.

Overview

This robot arm has three degree-of-freedom that is bending, expanding and contracting. When the robot arm is applied to a rehabilitation device, two kinds of control method are needed. One is a masterslave control, and the other is a trajectory control. The master-slave control is necessary when a physical therapist wants to give a rehabilitation motion to a patient.

While the trajectory control system is necessary when a sequential rehabilitation motion is applied to a patient. This robot uses a compact and inexpensive control system constructed and tested by using a low-cost embedded controller. The control system consists of a flexible robot arm, a low cost microcomputer, accelerometers, and small-sized quasi-servo valves which are developed by us using the on/off control valve. The master-slave control system and the trajectory control system were carried out using a PID control scheme.

Specifications

  • Degrees of freedom: 3
  • Pneumatic cylinder actuators: 3
  • Outer diameter: 100 mm
  • Quasi-servo valves: 6
  • Microcomputer: Renesas Co. Ltd., SH7125
    • Clock frequency: 16 MHz
    • ROM: 32 kB
    • RAM: 2 kB
    • 10bit A/D converter
    • 3ch PWM ports

References