Direct Control Parameter Tuning Method for Disturbance Attenuation Based on Variance Evaluation

The direct control parameter tuning methods derive the control parameters from the one-shot experimental input and output data with no need of help from the plant model. Most prior methods have been based on the perfect model matching design strategy so that the output of the closed loop system should follow the prescribed reference model output. In considering the disturbance attenuation problem, however, the model following criterion is a rather demanding specification because the disturbance response is just required to be suppressed around the target value. Therefore, the paper proposes a direct control parameter tuning method which employs the variance evaluation for the performance criterion to solve the disturbance attenuation problem. The proposed method tunes the control parameters so that the variance of the plant output approaches the variance of the reference model output. The proposed method can avoid an additive experiment where test signals are fed to the closed loop system for collecting the initial input and output data. The feature facilitates applying the proposed method to the industrial applications. Finally, the efficiency of the proposed method is demonstrated from a numerical example.