On the design and physical validation of a time-frequency controller
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2017, Editorial Department of Control Theory & Applications South China University of Technology. All right reserved. A general framework feasible for time-frequency (TF) controller design is presented in order to improve the dynamic characteristics in all working frequency domain of systems. And the effort is the application of wavelet analysis to enhance the performance of the traditional controller to reach the goal. Based on the principle, a new controller incorporates traditional PI controller into TF control to realize a novel concept properly termed as the time-frequency PI (TFPI) approach. Although optimal control performance can be achieved by tuning PI gains, however, the large number of parameters to tune in TFPI can be overwhelming. To address the particular issue, the ISTE criteria and the simplex optimization method is followed to optimize the gains. The TFPI concept is successfully applied to an electro-hydraulic hybrid system using a hardware-in-the-loop test rig to demonstrate feasibility. The performance of the TFPI controller is favorably evaluated against the conventional PI controller. It is found that TFPI controller can decrease the step response time of the system from 0.15 s that is the best result of the traditional PI controller to 0.06 s on the premise of the overshoot less than 1%. Besides, the comparison between this method and the other two control algorithm in literatures is conducted and the results prove further that the TFPI controller can improve the dynamic performance markedly and maintain the stability of the system at the same time.
