Energy-efficient tracking control of pneumatic cylinders

Pneumatic actuators have been widely used in industry for over a hundred years. However, it is well-known that pneumatic actuators have very poor energy efficiency. Also, it is difficult to achieve accurate positioning due to the inherent nonlinearity caused by air compressibility. This paper presents recent work in developing an energy-efficient tracking control strategy for pneumatic cylinders. The pneumatic system is initially transformed into a linear system description using the nonlinear input/output feedback linearization method. Then energy efficient velocity profile is derived based on optimal control theory. A servo/tracking controller is then designed to drive the system to follow the derived new energy efficiency velocity profile. The simulation study indicates that energy consumption can be reduced by 3–5%.