Efficient selection of inputs and outputs for robust control

A method is proposed to efficiently select controller inputs and outputs that assure a desired level of robust performance. It is based on an efficiently computable and sufficient existence condition test and it uses an effective search strategy. The selection condition is based on D-scales used in p-analysis, while the search strategy uses a method to generate all so-called minimal dependent sets. The D-scale test is followed up with a more accurate test employing expensive DK-iterations for smaller-sized subproblems. The tests together yield a good compromise between efficiency and effectiveness. This is demonstrated with an application for a large scale active suspension design problem with a ten DOF model of a tractor-semitrailer. In the application, seven actuators and twenty-one sensors are available to choose from.