Extension of a Multirate Output Feedback Control System for Improvement in Quantization Error

Abstract

This paper proposes a new method for designing a multirate output feedback (MROF) control system, where the update interval of the control input is an integer multiple of the sampling interval of the plant output. In the MROF method, the state variable is calculated without the observer. In this study, a conventional MROF system is extended with the latest information of a plant, and hence, new design parameters are obtained independently of the calculation of the state variable. As a result, the proposed method can resolve the quantization error independently of the calculation of the state variable and improve the control performance compared with conventional methods in which the latest information is not employed. Furthermore, the obtained control structure can be simpler than conventional methods. To demonstrate the effectiveness of the proposed method, it is applied to a linear system and a nonlinear system, and the control results are compared with conventional methods.