The digital LQG/LTR controller with a compensated observer for a tethered reflector/antenna system

The purpose of this paper is to develop a practical method of robustness recovery for discrete-time systems. It has been proven that the robustness recovery method for the LQG control with the filtering observer is also valid for discrete-time systems, but it is not valid for the control with the predicting observer. In engineering practice, however, due to the data transmission and computation delay the use of the filtering observer is not practical. One of the main contributions of this paper is to make the LQG/LTR methodology practicable in engineering implementation. The strategy here is to use the predicting observer at the beginning of every sampling period and then modified by the later data coming from the sensors; the error is compensated by resistor-capacitor circuits. The parameters of the compensator depend on the solution of a set of multi-element high powered equations. This methodology has been successfully applied to the reduced order controller for the orbiting tethered reflector/antenna system. Copyright (C) 1996 Elsevier Science Ltd