Discussion on: Comparison of Different Multivariable Control Design Methods Applied on Half Car Test Setup

The multivariable tracking accuracy on an automotive vibration test rig can be improved by extending the current industrial off-line iterative feedforward procedure with a real time feedback controller. This article compares three MIMO feedback control design procedures with respect to design complexity and obtained performance: (1) DK-iteration, the most common -synthesis method to design robust MIMO-controllers, (2) a control design based on static decoupling, which is a combination of a static input – output transformation to decouple the system, and independent SISO-controllers designed for the diagonal elements of the transformed system and (3) an inverse-based control design, which is also based on a decoupling transformation, but the decoupling is performed by a dynamic precompensator. The performance of these controllers is compared experimentally on a half car test setup. The tracking performance of the controller designs based on static or dynamic decoupling is comparable with the performance of the controller based on -synthesis. The decoupling-based controller designs, using standard SISO H1 techniques, are however much simpler and more straightforward.