Optimal design of controllers based on libraries and differential evolution

This paper presents a new method for optimal design of controllers based on a "library" thought and differential evolution. At first an extensible component library and a performance criteria library are established in the approach. The component library contains different types of system components which may be essential for controller structure. Appropriate components can be selected from the library and then combined to form a controller with richer structure. The performance criteria library includes some common control performance indexes. Users can choose one from it according to performance requirements. Then, the differential evolution algorithm is utilized to optimize the parameters of each component in order to find the optimal solution and ultimately obtain the controller structure and parameters which meet requirements. Simulations were done on different types of control objects. Simulation results show that the controllers designed by the proposed method for different types of control objects generally have better comprehensive performance than the PID controllers designed by conventional methods, differential evolution and genetic algorithm. Validity, stability and generalizability of the proposed method were also tested and verified.