A study on tracking peformance of the pneumatic system with enhanced NPID controller

An investigation on the performance of enhanced Nonlinear Proportional Integral Derivative (ENPID) controller is presented in this paper. The study is focused on the potential of the controller to perform well in tracking set point of pneumatic actuator system. Two control strategies of the ENPID are considered in this paper, namely Multi-rate NPID (MN-PID) and Self-regulation NPID (SN-PID). These control strategies are tested against NPID and conventional PID controller. Also, the dead-zone compensation (DZC) is applied to the system to overcome the dead-band of the valve. Feed forward path is also included to improve the tracking performance. Two different input signals i.e. sinusoidal and S-curve waveforms are used to evaluate the performance of the techniques. To further examine the controller performance, the frequency and amplitude of the sinusoidal test signal are varied. The effectiveness of the proposed controllers is verified through simulation and experimental studies.