Trajectory control of robot arm using flexible pneumatic cylinders and embedded controller

Robots, due to their excellent speed, accuracy and cost-effectiveness in repetitive tasks, now have a tendency to be used in rehabilitation field. A simple trajectory control of robot arm using flexible pneumatic cylinders and embedded controller which can be used as rehabilitation for human wrist is described. The system consists of the flexible robot arm, an accelerometer, embedded microcomputer, a potentiometer and compact quasi-servo valves. The analytical model for trajectory control is proposed and applied on the flexible pneumatic robot arm. The proposed trajectory control method does not need a linearized model which is commonly used in a robot arm. The flexible structure has the characteristics of high safety such as not to cause harm to user and is suitable for use in therapeutic devices. The trajectory control can help patients recover more quickly by repeating the movements based on the patient's individual condition. Both experiment and simulation show that the trajectory control of robot arm can be realized for several kinds of trajectory by using the proposed control method and the tested robot arm.