Control Of System With Model Uncertainties And Parameters Uncertainties

For a variety of reasons, the uncertainties usually exist in the system. These uncertainties will lead to system model often difficulty to be precise describe. If these uncertainties does not be taken into account in the designing of control system, It will cause the designed control system becomes unstable system or can not get the really required performance of the control object.In this paper, the main work is to study how to control the system with model uncertainties and parameter uncertainties. The uncertainties of system was classified and taken into mathematical model. Introduce and compare the main previous control methods and analysis their strengths and weaknesses. A design method of robustμ-synthesis controller was proposed to solve the perturbation for the structural problem. A simply method was introduced to change the decentralized perturbation into diagonal matrix perturbation. The robust performance problem of system was transformed into the robust stability problem of augment system via the introduction of a fictive uncertainty module. This method can provide a good disturbance rejection and is more robust to parameter variations and reduce the conservative of the system. The weighting function plays an important role in robust control problem, the paper discusses how to choose the weighting function and the selection principle is given. At the end of the paper, an example– satellite antenna tracking system was given. Based onμ-synthesis theory, theμ-synthesis controller was design. Simulation results indicate thatμ-synthesis can provide a good disturbance rejection and is more robust to parameter variation.