Non-uniformly Sampled Relay Auto-tuning Digital PID Control

Relay feedback auto-tuning PID control has been widely used, but the waveform of oscillation test is not pure sinusoidal form, which has a certain influence on the identification of characteristic parameters and the tuning effect of PID parameters. The relay feedback auto-tuning digital PID control system causes the non-sinusoidal oscillation waveform in the form of high order harmonic frequency and frequency aliasing carried on the thorough research in this paper. Bring in the non-uniformly sampled to the relay feedback auto-tuning, the mathematical model of the system after discretization is derived, and building system model for the simulation to verify the effect in the last.