Trajectory controls and its analysis for robot arm using flexible pneumatic cylinders

Due to their excellent speed, accuracy and cost-effectiveness in repetitive tasks, now extensive use of robotic technology for medical applications is in rehabilitation robotics. The trajectory controls and analysis of robot arm using flexible pneumatic cylinders and embedded controller which can be used as rehabilitation for human wrist are described. The system consists of the flexible robot arm, an accelerometer, embedded microcomputer, a potentiometer and compact quasi-servo valves. This robot arm has three degree-of-freedom; bending about x and y axis (2-DOF) and extending-and-contracting (1-DOF). Two analytical models for trajectory controls are proposed and applied on the flexible pneumatic robot arm. The difference between two proposed models is as follows. One is needed to be linearized which is commonly used in a robot arm. Another does not need a linearization that is a direct method. The trajectory control can help patients recover more quickly by repeating the movements based on the patient's individual condition. Both experiments and simulations from two trajectory models show that the proposed trajectory controls of robot arm can be realized by using the proposed control methods and the tested robot arm.