Design of a Performance-driven One-parameter Tuning Controller

Abstract

The properties of most real systems vary every moment. For such systems, performance-adaptive control systems, which assess current control performance and tune their controller based on the assessment, are effective. This paper proposes a one-parameter tuning method as one of design methods of the performance-adaptive control systems. When the current control performance is diagnosed as being poor, the conventional performance-adaptive control systems redesign their controllers using the results of system re-identification. However, the system has a risk that the redesigned controller may cause further deterioration of the control performance depending on the identification accuracy of the estimated parameters. In the proposed method, the controller has a unique user-specified adjustable parameter. The controller can improve the control performance by adjusting only the parameter. However, only if the desired control performance cannot be maintained by adjusting the parameter because of drastic changes in the controlled object, the control system redesigns the controller using the estimated system parameters. Thanks to this strategy, the number of controller redesigns using the estimated system parameters is decreased when compared to the conventional performance-adaptive control system. It can also reduce the risk of further deterioration of the control performance because of the controller redesign. The effectiveness of the proposed method is evaluated by simulations and application to a weigh feeder that is one of food process systems.