Optimal PI controller tuning for dynamic TITO systems with rate-limiters based on parallel grid search

As dynamic nonlinearities, rate-limiters make it difficult to obtain globally optimal parameters for proportional-integral (PI) controllers to optimize a given control performance index. This paper proposes a parallel grid-search method to determine optimal PI controller parameters. First, the latent parameter set is formulated subject to feasible ranges and search steps for controller parameters. Second, values of the control performance index are calculated for all members in the latent parameter set. The parameters corresponding to the best control performance index are determined as optimal PI controller parameters. Parallel computations at multi-core CPUs are exploited to ensure all required computations to be completed within a given time span. Numerical and experimental examples are provided to support the proposed method.