Decoupling feedback control for improved multivariable vibration test rig tracking

Within the framework of the tracking problem on an automotive vibration test rig, a new control strategy is developed which is applicable to square multiple-input-multiple-output systems (MIMO-systems) with a certain degree of symmetry. Classical MIMO-controller design is a three step procedure: response measurement, MIMO-identification and MIMO-controller design. The latter two steps are often very cumbersome. In this paper, a new procedure is proposed which avoids these steps. It consists of the following steps: response measurement, almost decoupling of the MIMO-system into multiple single-input-single-output systems (SISO-systems) by transformations of the inputs and the outputs, SISO-identification of the decoupled systems, and multiple SISO-controller design. The great advantage of the decoupled model, is that it allows the use of well-understood, robust SISO-controller design methods. This paper shows that the automotive vibration test rig can be described with a decoupled model, at least as accurate as with a full MIMO-model.status: publishe