Active Disturbance Rejection Control for a class of parallel systems

This paper discusses the control of parallel systems by active disturbance rejection control technique. The concept of parallel systems is introduced. A class of n-th order parallel systems are analyzed and the total disturbances are determined respectively when the control algorithm is selected as Active Disturbance Rejection Control (ADRC) and Alternative ADRC (Alt. ADRC). Two kinds of parallel systems are given as examples to show the process of determining the total disturbance. The procedure of solving the control problem of a second order parallel system is given in detail. Simulation experiments on flexible structures show that the ADRC technique has a much better performance than the traditional Positive Position Feedback (PPF) control strategy when dealing with unknown disturbance and unmodeled modes.