A robust controller design method for a flexible manipulator with a large time varying payload and parameter uncertainties

A new robust controller design method is proposed to obtain a less conserva tive feedback controller and it is applied to a single-link flexible manipu lator. The objective is to maximize the control performance guaranteeing th e robust stability when regulating the tip position of the flexible manipul ator in the presence of a large time-varying payload and parameter uncertai nties such as stiffness and joint friction. A descriptor form representatio n, which allows separate treatment of payload uncertainty from other parame tric uncertainties, is used to reduce the conservatism of the conventional robust control approaches. Uncertainty of the payload in the inertia matrix is represented by polytopic approach and the uncertain parameters in the d amping and stiffness matrices are treated with descaling techniques. Using aforementioned techniques, the robust LQ controller design problem for a fl exible manipulator based on the guaranteed cost approach is formulated. The n, the formulated problem is solved by LMIs.