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Design of optimal PID controller with $$\epsilon$$-Routh stability for different processes. (English) Zbl 1299.93186
Summary: This paper presents a design method of the optimal proportional-integral-derivative (PID) controller with $$\epsilon$$-Routh stability for different processes through Lyapunov approach. The optimal PID controller could be acquired by minimizing an augmented integral squared error (AISE) performance index which contains control error and at least first-order error derivative, or even may contain $$n$$th-order error derivative. The optimal control problem could be transformed into a nonlinear constraint optimization (NLCO) problem via Lyapunov theorems. Therefore, optimal PID controller could be obtained by solving NLCO problem through interior method or other optimization methods. The proposed method can be applied for different processes, and optimal PID controllers under various control weight matrices and $$\epsilon$$-Routh stability are presented for different processes. Control weight matrix and $$\epsilon$$-Routh stability’s effects on system performances are studied, and different tuning methods’ system performances are also discussed. $$\epsilon$$-Routh stability’s effects on disturbance rejection ability are investigated, and different tuning methods’ disturbances rejection ability is studied. To further illustrate the proposed method, experimental results of coupled water tank system (CWTS) under different set points are presented. Both simulation results and experiment results show the effectiveness and usefulness of the proposed method.
MSC:
 93C85 Automated systems (robots, etc.) in control theory 93C80 Frequency-response methods in control theory 93B50 Synthesis problems
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