An algorithm for multivariable-system closed-loop performance assessment using step data

Among approximate-model techniques, assessment of the closed-loopperformance deterioration arising from the approximate modelplays an important role in control-system design. The earlywork of Owens & Chotai (1983) proposed a method to boundthe closed-loop output transient performance deterioration.But in practice it has been found that the assessment for multivariable(MIMO) systems is not good as the one for single-input single-output(SISO) systems. The obstacle comes from the non-commutationof multivariable convolution operators (Owens & Chotai 1983).This paper proposes a one-step method to assess the closed-loopresponse of a MIMO system. The algorithm to implement the assessmentis discussed. Because the new algorithm assesses the outputtransient performance without the need to assess input performance,the uncertainty in closed-loop output predictions has been reducedgreatly. On leave from Department of Electrical Engineering, ZhejiangUniversity Hangzhou, China.