Fault Tolerant Control for Trajectory Tracking of a Pneumatic Servo Positioning System

Pneumatic technology plays an important role in modern mechatronic systems. They widely use in industries due to good power density, high travel speed, cleanness and simple operation mechanism. Pneumatic actuators exhibit nonlinear behavior in control applications given by air compressibility, mass flow characteristics, etc. Smooth and precise motion control in pneumatic systems can be improved by using appropriates model of system. In this study, a novel mathematical modeling of a laboratory servo pneumatic system is presented and validated. PID and sliding mode controllers are designed for propose of position control and their performance are compared in terms of tracking accuracy and operating speed. As novelty of the paper, trajectory tracking under actuator faults is investigated. The results indicate that the sliding mode control method has better performance in trajectory tracking in comparison with the PID method especially under actuator faults and failures.