Positioning Control and Force Feedback Control of a Flexible Arm Applying a MRACS

This paper describes the application of a Model Reference Adaptive Control System (MRACS) to the positioning control and the force feedback control of a flexible arm. The flexible robotic arm is simply modelled as flexible cantilever beam revolving at a joint. The mathematical models of the flexible beam for positioning and force feedback are induced as a lumped parameter system. By discretizing these models through a sampling period, discrete time equations are obtained and a discrete MRACS is designed for each discrete model. A set of experiments is carried out to examine the effectiveness. In the experiment for positioning cotrol, a CCD camera and image processor were used to measure the position of the tip of the beam. In the experiment for force feedback control, a load cell was used to measure the force acting on the end of the beam. A dc servo motor was used as an actuator. The adaptive control system can be designed by the simple algorithms and structure. Experimental results have shown that the control performance is good and the constructed MRACS is effective.