Nonlinear component-based modelling and hardware-in-the loop simulation of servo-pneumatic systems

Modelling and control of pneumatic systems are tedious and difficult because of the inherent nonlinearity associated with these systems. In this paper, a component-based modelling approach is proposed to create a nonlinear mathematical model of servo-pneumatic systems. According to the proposed modelling approach, the system is decomposed into the main components, the linkage nature between components is identified, and the model of each component is created separately. A generalised nonlinear model of pneumatic system is created by simply aggregating the model of the separate components. This model is then validated using a real pneumatic system available in De Montfort University labs. Experimental results show that real and simulated responses agreed well. Afterward, the developed model is used to design and tune PID-based controller using two different methods. Both controllers have been tested on the real system through hardware-in-the-loop (HIL). Experimental results show that both controllers succeeded to follow a reference speed profile. The proposed approach should lead to reduction in model complexity, faster model formulation, and high model accuracy and reliability.