Fuzzy precompensated PID controllers

While proportional integral derivative (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, the authors propose a fuzzy logic-based precompensation approach for PID controllers. The authors demonstrate the performance of their scheme via experiments performed on a DC servomotor position control testbed under varying load conditions. The authors´ results show that the fuzzy precompensated PID controllers have superior performance compared to conventional PID controllers. In addition, the proposed scheme is robust to variations in load. In the experimental testbed, the variations in loading conditions correspond to variations in the level of nonlinearities in the plant. The authors´ scheme is easily implemented in practice simply by adding a fuzzy precompensator to an existing PID controller