A direct design method of controllers based on the frequency response indices for servo systems

To improve the design efficiency of servo systems, a novel controller design method is proposed based on the desired closed-loop transfer functions satisfying the required frequency response indices. Taking into account the constraint due to the physical realizability of controllers, the desired closed-loop transfer functions are specified. In addition, the analytical expressions for certain kinds of performance indices and design constraints, including dual-ten indices of frequency responses, crossover frequency, phase margin, and magnitude margin, are derived. Then, the principles for controller parameter determination are discussed. The controller design is formulated as an optimal problem with a variety of constraints, and the design guidelines are presented. At last, experiments are conducted to verify the effectiveness of the proposed method.