Digital redesign of observer-based weighting switch controller for cascaded analog systems with state saturation and external loads

This paper presents an observer-based weighting switch controller for dealing with the problem of cascaded systems with state saturation and external loads. This method improves the generally poor transition response and output deviation caused by state saturation and external loads. In order to maintain the state-saturation limits, we adopt the evolutionary programming optimal search technique to find the optimal switching parameters for the weighted switch controller. Also, a digital redesign method is utilized to replace a designed high-gain analog controller with a low-gain digital controller. It is shown that the digitally redesigned outputs closely track the analogously controlled outputs. The digital redesign technique is then extended to find the digital version of the continuous-time observer. An illustrative example is demonstrated to show the effectiveness of the proposed procedure.