Semi-intrusive multivariable model invalidation

This paper introduces a mechanism for testing multivariable models on which model-based controllers are designed. Although external excitation is not necessary, the data collection includes a stage where the controller is switched to open-loop operation (manual mode). The main idea is to measure a certain "distance" between closed-loop and open-loop signals, and then trigger a flag if this "distance" is larger than a threshold level. Moreover, a provision is made for accommodating model uncertainty. Since no hard bounds are assumed with respect to the noise amplitude, the model invalidation mechanism works on a probabilistic framework.