PID Controller Design And Simulation Research Based On H_∞ Control Theory

Although many advanced control methods appear continuously, PID controller is the most widely and maturely used controller in process industry. The conventional parameters-tuning method of PID controller depends on the plenty of experiences of the technical men, it waste plenty of time and energy. There are many kinds of uncertainties in complex process. For this kind of process, The conventional parameters-tuning method of PID controller can hardly achieve perfect control effects. In order to strengthen the tolerance of PID controller to Process'uncertainties, two parameters-tuning methods of PID controller is studied in this paper. And through simulation researches, the performance and robustness of the robust PID controllers are proved.In chapter four, the parameters-tuning methods of PID controller based on H_∞control theory is investigated. Based on Youla parameterization principle, andthrough optimizing the sensitivity function of the system, the parameters-tuning method of PID controller is accomplished. With regard to time-delay process, the first order Pade approximation method is adopted. Finally simulation researches on SISO time-delay plant and MIMO time-delay plant. Through analysis, for system's performance and robustness, this paper's method can get better control effect.In chapter five, the parameters-tuning methods of PID controller based on H_∞loop-shaping principle is studied. This method based on the conventional loop-shaping theory and modern H_∞control theory. The designing procedure of thePID controller is given and the selection of weighting function is discussed in detail in this chapter. Finally through the algorithm of the parameters-tuning methods of PID controller, simulation researches on SISO time-delay plant and MIMO time-delay plant.In all of the two methods stated above, the configuration is fixed, the PID controllers are functions of parameterγ, whose value will affect the performance and robustness of the system. The range ofγand its effect to the control performance of the systems are analyzed, and relevant simulation researched are accomplished in this paper.