MULTIVARIABLE PID CONTROL VIA ILMIs: PERFORMANCES ASSESSMENT

This paper addresses the problem of performance assessment for MIMO PID controllers. An efficient comparative analysis is established using two Iterative Linear Matrix Inequality (ILMI) approaches. To evaluate the robustness and the performances of each ILMI approach, four tests are carried out on the closed-loop system including White Gaussian noise, set point changes, parametric perturbation, and multiple time-delays influence. Different performance criterion such as IAE, ISE, ITAE and ITSE are also presented to evaluate the closed-loop system performances. The quadruple-tank process as a benchmark of minimum/non-minimum phase systems is applied to show the effectiveness and utility of the proposed analysis. The comparative analysis between the two PID controllers leads to nearly similar performance results in parametric perturbation and noise attenuation but different results in terms of set point changes, multiple time-delays influence and performance indices.