Performance Assessment Methods of MIMO Control Systems based on Output Variance Limit

In this paper, performance assessment methods of multivariable control system subject to piecewise constant time varying disturbance dynamics has been studied. The problem appeared on most industrial controllers are linear time invariant (LTI) while the process are often time varying. Take a series of disturbance dynamics that can be modelled by piecewise linear disturbance models, namely piecewise linear time varying (LTV) disturbance dynamics. The problem is formulated as searching for a multi-input multi-output (MIMO) benchmark control. In the paper, a method, which is based on output variance limit, is proposed to assess the performance of MIMO control system. A weighted performance index is constructed through dividing time varying disturbance in to three types of constant disturbance. The upper and lower limits of the output variance would be determined by a special principle, and then Integral of time-weighted absolute value of the error (ITAE) would be used to optimize the parameters of controller and give the feasible controller model. The results show that the method is simple and available in practical application.