Control of the Electro-pneumatic VGT Actuator with Friction Compensators

This paper describes friction compensation based control of an industrial pneumatic actuator used for the variable geometry turbocharger (VGT). Adaptive LuGre model for friction has been used in this work. Friction force that is responsible for hysteresis and hunting phenomenon in the position control is compensated with two different control strategies designed to improve low velocity position tracking. The first approach is related to the knocking the input signal to reduce position error. In the second approach, an adaptive LuGre model based friction observer is proposed for friction compensation. At the end both approaches are compared with the help of experiments on the actuator.