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A modified global harmony search algorithm for robust PID controller tuning

The robust turning of proportional-integral-derivative (PID) controller is a hard work, and it is restricted by multiple H∞ performance criteria. The robust PID controller turning is essentially a constrained optimization problem, therefore, a modified global harmony search algorithm (MGHS) is proposed to handle this problem. The MGHS algorithm is a population-based algorithm, and it updates the worst solution in each iteration so as to improve the quality of all candidate solutions. In this paper, we combine the MGHS and a penalty function method to trade off the objective function value and constraint violations. Experimental results demonstrate that the MGHS can find satisfactory controller parameters for robust PID controller tuning.