Large feedback control design with limited plant information

A novel method is presented that provides a novel, large feedback design with adequate stability margins without a plant model. First, a PID controller is found using on-line tuning. Next, the closed-loop transient response of the PID system is used to define a bandwidth, and the PID compensator transfer function is used to determine the plant gain and heuristically estimate the plant slope at crossover. Then, these parameters are used to find the compensator. A prefilter is designed to improve transient response, and adjustments are suggested for plants possessing feedback-limiting dynamics. Analytical examples and experimental data illustrate the approach's efficacy.