Control of system with large parametric uncertainty using multiple robust controllers and switching

In practice, models always have uncertainties due to unavoidable factors. A multiple model robust control method for linear multi-input and multi-output plants with large parametric uncertainty is presented in this paper. The candidate controllers are designed by H-inf control method and by analyzing how model uncertainty influences the error of estimated output, a new estimator and switching index, which can evaluate the system norm of model uncertainty, are proposed. By this way, the control system can be equivalent to a switching system with small uncertainty whose system norm is limited. The robust stability of the closed control system is studied by using small gain theorem. And furthermore simulations have been done on a second order inertial system to validate its effectiveness of this new multiple model robust control method.