Frequency response-based decoupling tuning for feedforward compensation ADRC of distributed parameter systems

Abstract

A practical tuning method is proposed via frequency response or even cut-off frequency for active disturbance rejection control (ADRC) of distributed parameter systems (DPSs), whose models are hard to get but frequency characteristics are easy to measure. Moreover, a novel control structure, feedforward compensation ADRC (FC-ADRC), is presented to decouple the tuning of tracking and disturbance rejection (DR). The frequency response-based tuning method initializes the parameters and then iterates them to the optimal solution by following a simple rule. The basic idea of FC-ADRC is skillful. The closed-loop system is tuned to the desired dynamic via ADRC. Such a control system is a platform for a compensation block to be combined in cascade. ADRC only rejects disturbance while the feedforward compensation purely tracks. Simulation of six accepted irrational transfer functions (ITFs) shows the frequency response-based tuning for FC-ADRC performs better than compared control methods in robustness and performance of tracking and DR. The stability is proved based on the Nyquist criterion for DPSs. Two experiments verify the effectiveness of decoupling tuning and frequency response-based tuning. Therefore, frequency response-based tuning for FC-ADRC is not only a skillful and effective control structure but also a practical and compact method.