Uncertainty vs Performance Trade-Offs in Robust Feedback Control: A Mimo Case Study

We use a non-trivial MIMO three-cart Mass-Spring-Dashpot (MSD) system to demonstrate how performance (disturbance-rejection) is reduced as the level of uncertainty in one or two real parameters is increased in the presence of unmodeled dynamics. All designs are carried out by the mixed-mu robust synthesis methodology. Comparisons are made: (a) in the frequency-domain, (b) by RMS values of key signals and (c) in time-domain simulation results