A Construction of an Inverse Model with Cut-off Filter and Its Application to Model Feedback Control System

An inverse system for a given time-invariant system has been used as a compensator. However, in control systems where traditional inverse system is applied, the adverse effects of sensor noise may give seriously influence to the systems because the inverse system generally has a characteristic of high gain in high frequency area. Therefore, in these control systems other compensators except the inverse system must be constructed with complex characteristics.In this paper, a design method of a new inverse model with cut-off filter for Model Feedback Control System (MFCS) is proposed. Inverse model designed by the proposed method is an approximate inverse model for a given model. The approximation can be estimated by norm criterion for the difference between the model and the biproper transfer function used for construction of the inverse model. In order to demonstrate the usefulness of the proposed inverse model, this inverse model is applied to the MFCS. By theoretical and numerical analysis it can be shown that the proposed inverse model can reduce sufficiently the effects of sensor noise in the MFCS.