Robust Controller Design Satisfying Iso-Damping Characteristics

Abstract

In this paper, we propose a robust controller design that satisfies the characteristics of phase margin and Iso-damping braking using a reduction model with secondary delay time.
For higher-order models, it is not easy to find a specific frequency that satisfies the so-damping and fault margins. As the model reduction method, the reduction method using a Nyquist plot shows excellent characteristics in the frequency domain and time domain. In this paper, the reduction model with the second delay time considering the improved steady-state is applied.
The PID controller design method that satisfies the characteristics of phase margin and iso-damping is as follows. First, the parameter value of the Ti controller that satisfies the characteristics of iso-damping is determined by using the reduction model with the second delay time. Second, the Kc and Td parameter values are obtained by considering only the phase margin in the control transfer function that satisfies the phase margin and gain margin. The PID controller parameters thus obtained have the characteristics of robust control by satisfying the characteristics of phase margin and iso-damping. Simulation results show that the proposed method is excellent for lower and higher models.
In this paper, we designed a PID controller that satisfies the phase margin and iso-damping using a reduced model. In order to satisfy the above characteristics, improvement of the model reduction algorithm is required. Extending this method will improve the performance of the classic PID controller.