Research Of The Dynamic Performance Of DC Servo Control System Based On Fractional Order PID

Comparing the integer order PID controller，the fractional order PID controller includes an integration orderλand a differential orderμ, whereλ is an order impacting the control system steady state and μ is an order impacting the control system dynamic. The research verifies that the fractional order PID controller has more flexibly and strong robust because of the unique structure. At present, the study is most concentrated in two aspects which are parameter setting and controller design，but which is very few in the the practical application of control system. In this dissertation, the fractional order PID controller is applied to the DC servo control system to improve its dynamic performance, the main works of the dissertation include:The theory of fractional order calculus is introduced. It verifies that the operator of order can be flexible to change system of amplitude frequency and phase frequency curve of the slope based on analyzing the frequency of fractional calculus operator performance. The Outaloup recursive filter is accuracy for calculus operator approximation, and it verifies the fractional order system stability is variability because the fractional order system stable region is relative for the order of infinitesimal calculus.The optimal fractional order PID controller parameter setting method is designed which is based on that analyzing the frequency of the fractional order controller performance. Through the analysis of the fractional order PID controller and the influence of various parameters on the control system for simulation examples compared to the control performance of integer order PID controller, it verifies the fractional order PID controller has strong robust and is helpful to improve the dynamic performance of control system,The fractional order system has the high dynamic performance with the unique structure, but which’s controller design becomes extremely difficult because of the higher order system. This dissertation briefly introduces the traditional methods of H2 norm model reduction, then a new model reduction based on that is proposed, which extends to the fractional order after the mode reduction and models a large variety of higher order systems with greater accuracy. And the optimal fractional PID controller is designed with the constraint conditions of the reduced order model of the phase margin and gain crossover frequency and robustness to gain variation.Servo control system simulation model is established based on the project requirements for the design of the control system to calculate and determine the type and parameters of the motor. At the same time, under the requirements of dual-ten index, the bandwidth of the feedforward controller and the PID controller of the DC servo system was compared, of course the comparison and analysis of the velocity and acceleration at the same bandwidth. The simulation results show that, the DC servo system of fractional-oder PID controller has better dynamic performance.