Abstract:

The fractional order proportional-integral-derivative(PID) controller is the expansion of the classical integral order PID controller in complex domain. Two variable parameters λandμ are brought to expand the tuning range, but the controller is made more complicated. For the characteristics of the fractional order PID, a modified differential evolution algorithm with parameter self-adjusting is presented to tune the controller. To choose the objective function, the weighted addition of error and control signal as the disadvantage of overshoot control with integrated time and absolute error criterion are introduced. Theoretical analysis and simulation are carried on with integer order plant and fractional order plant separately. The simulation results illustrate the effectiveness and accuracy of the proposed method.