Dynamic output-feedback guaranteed cost control for linear systems with uniform input quantization

There have existed the researches on guaranteed cost control for systems with the dynamic or logarithmic quantizer; however, intensive studies not only on continuous-time output-feedback linear systems with uniform input quantization but also on guaranteed cost control for such systems have not been carried out thus far. This paper first solves the problem of guaranteeing the linear quadratic (LQ) cost for continuous-time output-feedback linear systems with uniform input quantization. The proposed output-feedback controller comprises the main and the additional control parts. The former part is designed as a linear dynamic output-feedback controller for determining the fundamental characteristics of the system associated with the LQ cost, and the latter part is constructed as an integer multiple of the quantization level for eliminating the effect of uniform input quantization. The additional control part adopts the state estimate instead of the state itself, which causes the state estimation errors. By computing their quantity added to the upper bound of the LQ cost, this paper shows that the proposed controller still guarantees the LQ cost despite the state estimation errors.