Research And Design Of Optimized Fractional-Order PID Controller

In recent years, with the development of the fractional-order calculus theory, it is worth while researching the fractional-order PID controller which is a general form of the conventional PID controller. Due to the extra tuning knobs, fractional-order PID controllers are expected that better control performance and robust can be achieved. In this thesis, fractional-order PID controller is mainly researched in the following field.Firstly, the Oustaloup approximation of the fractional-order differentiation is achieved, and masked the Oustaloup approximation using SIMULINK model, so that it's convenient for solving the fractional-order differential equations. What's important, the fractional-order PID controller is composed by the subsystem.Secondly, the method of designing the optimized fractional-order PID controller is proposed. While designing the optimized fractional-order PID controller, the position servomechanism is used as our controlled object, and the ITAE and ISE as our optimization criterion is chosen. Through the comparison of the optimized integrator-order PID controller, it is proved that the optimized fractional-order PID controller can be better than the optimized integrator-order PID controller in control performance and robust.Thirdly, the nearest optimized fractional-order PID controller which can reduce the time which is wasted in design the optimized fractional-order PID controller is proposed. While getting the better control performance, the whole process is more quickly than before.At last, a experiment of the optimized fractional-order PID controller, the nearest optimized fractional-order PID controller and the fractional-order PID controller which is optimized by using the Genetic Algorithm is made to do a comparison of the three fractional-order PID controller's control performance and the robust of the fractional-order PID controller while controlling the controlled system. From the comparison of the three fractional-order PID controller, it is proved that the optimized fractional-order PID controller can achieve the best control performance and robust. While the nearest optimized fractional-order PID controller also can achieve the better control performance than the fractional-order PID controller which is optimized by Genetic Algorithm in the time domain and the frequency domain. And achievement of the thesis is summarized, ideas about the optimized fractional-order PID controller are introduced, and the optimized fractional-order PID controller research forecast is proposed also.