On disturbance rejection proportional–integral–differential control with model-free adaptation

In this paper, an adaptive disturbance-rejection proportional–integral–differential (PID) control method is proposed for a class of nonlinear systems. First, PID-type criterion is introduced in a model-free adaptive control (MFAC) framework, which gives an optimal control interpretation for PID controller. Then, the design of adaptive disturbance rejection PID is proposed based on this new interpretation to realize controller gain auto-tuning. Due to the ingenious integration of active disturbance rejection and adaptive mechanism, the proposed adaptive disturbance rejection PID control scheme exhibits better control performance than MFAC case. Furthermore, the boundedness of controller gain, the convergence of tracking error and the bounded-input–bounded-output stability are proved for the proposed control system. Finally, the effectiveness of the proposed method is verified by numerical simulation.