Realization of causal current output-based optimal full/reduced-order observer and tracker for the linear sampled-data system with a direct transmission term

Realization of causal current output‐based optimal full/reduced‐order observer and tracker for the linear sampled‐data system with a direct transmission term from input to output is proposed in this paper. First, a high‐gain optimal linear quadratic analog tracker based on the reduced‐order observer is proposed for the system model with a direct transmission term from input to output, so that it can effectively induce a high quality performance on state estimation and trajectory tracking design theoretically. Then, the prediction‐based digital redesign method enables it to make the digitally controlled system to track the desired trajectory closely. However, there induces a causal problem on the realization of current output‐based optimal full/reduced‐order observer and tracker for the sampled‐data system with a direct transmission term form input to measured output. To overcome this problem, a realization of the causal observer‐based sampled‐data tracker is newly proposed in this paper. An illustrative example is presented to demonstrate the effectiveness of the proposed method.