Optimal Tuning PID Controller Gains from Ziegler-Nichols Approach for an Electrohydraulic Servo System

The Proportional-Integral-Derivative (PID) controller is widely used to control industrial systems due to its ease of implementation, flexibility and well-known theory. The Ziegler-Nichols  method is the primary method of adjusting this gains controller. Unfortunately, this method generates limited performances, especially on nonlinear systems. This paper shows the optimization of the gains of the PID controller from the values of the gains obtained by the ZN method. To do this, the Matlab Response Optimization tool is used to control the angular position of an electrohydraulic servo system. The initial conditions of this optimization process are the gain values adjusted by the ZN method. The numerical results obtained after a few iterations show a reduction of approximately  in the tracking error for a sinusoidal input. Unfortunately, the performance improvement is not achieved for the step signal input because only the sine wave was used as the signal reference requirement for the optimization procedure.