Fuzzy precompensation of PID controllers

While PID controllers are widely used in industrial applications, they exhibit poor performance when applied to systems containing unknown nonlinearities, such as deadzones, saturation, and hysteresis. In this paper, we propose a fuzzy logic-based precompensation approach for PID controllers. We demonstrate the performance of our scheme via experiments performed on a DC servomotor position control testbed under varying load conditions. Our results show that the fuzzy precompensated PID controller has superior performance compared to conventional PID controllers. In addition, the proposed scheme is robust to variations in load. In our experimental testbed the variations in loading conditions correspond to variations in the level of nonlinearities in the plant. Our scheme is easily implemented in practice simply by adding a fuzzy precompensator to an existing PID controller