Hybrid control of complex dynamical systems

To address some of the issues related to the control of complex dynamical systems, such as simultaneous achievement of high performance and stability robustness over a wide operating envelope, several topics have been studied in the dissertation. First, it introduces the design of superstable controllers and observers. Based on one property of the superstable systems, i.e., prefixed output bound when the input is bounded, one can attenuate the effects of any persistent-but-bounded input disturbances on the outputs. Algorithms for designing such controllers and observers are given and numerical examples show their efficacy. Second, the conceptual design and validation of switching decision and control system is studied. The switching decision is realized with a bank of feedback controllers that are designed for different operating envelopes and a variety of performance and robustness specifications. The role of switching control is to orchestrate the bank of controllers to achieve smooth handling of the plant over the entire envelope under different operating conditions. The decision and control system not only maintains stability of the switching operations by promptly suppressing any resulting oscillations, but also attenuates the detrimental effects of modeling uncertainties and exogenous disturbances. Moreover, a simulation testbed of a commercial-scale rotorcraft is built for purpose of control method validation. The switching decision and control system designed has been tested on the testbed and its efficacy is shown.