A simple self-tuning speed controller

The authors present a self-tuning PID adaptive speed controller for AC motor speed regulation with a very low computational algorithm. The traditional industrial solution to obtain acceptable characteristics for tracking and process regulation consists to find a compromise point for both two situations, or in advanced regulators, to adopt a simple two degrees of freedom PID control, whose parameters are fixed by auto-tuning. But when plant parameters vary strongly this auto-tuning algorithm have to be continuously started. In those cases, this work proposes a single self-tuning PID control method with a simple adaptation mechanism. The controller is based in a novel fuzzy adaptation method that changes the parameters of an standard PID controller, concretely integral constant K/sub I/, for adapting it to the plant evolution according to the dynamics of the system. This fuzzy logic adaptive strategy has been readily implemented, with very fast learning features and very good tracking characteristics. The developed controller has been also compared with other classical controls, and experimental results demonstrate the robustness of the suggested algorithm in contending with varying load and torque disturbance.