MOESP approach for designing a compensation input to linear unknown SISO systems

This paper deals with a compensation method for linear unknown single-input-single-output systems. A mechanical system is often suffered by frictions, so that aging degradation is unavoidable. If the original controller does not bring out a control performance, controller redesign is demanded. However it sometimes degrades the control performance due to variance of the system dynamics. The present paper considers supplying the system with a compensation input satisfying the control performance. Since the transfer function of the system is unknown, we apply a test signal merely one-time and observe its response to get hold of the system characteristics. From this once trial, several pairs of the input-output signals are generated by applying the MOESP approach. Lack of control performance, which appears on the output channels, is compensated by a linear mixture of the generated output signals. By using the mixing coefficient, the compensation input signal is back calculated. Effectiveness of the proposed design method is demonstrated through numerical simulations.