MODELING AND SIMULATION OF STICK-SLIP PHENOMENON IN PNEUMATIC CYLINDER

Abstract

Stick-slip phenomenon may occur in the motion of pneumatic cylinders at
low velocities and causes difficulties in controlling the position/velocity of the
pneumatic cylinders. Therefore, a comprehensive understanding of stick-slip
characteristics in the pneumatic cylinders plays an important role in improving
the controllability of pneumatic systems. This paper investigates the dynamic
characteristics of pneumatic cylinders when stick-slip occurs and develops a
suitable mathematical model of the system to simulate this phenomenon. To
accomplish this, an experimental setup of the pneumatic servo system is
considered. The characteristics of the cylinder when slip-stick occurs including
piston position, pressures in the cylinder chambers and cylinder friction force
are measured and analyzed. A mathematical model of the system is proposed
in which a dynamic friction model in a pneumatic cylinder is developed based
on a modified LuGre model. The comparison between simulation and
experiment results show that the proposed mathematical model can describe
the stick-slip phenomenon in pneumatic cylinder with a relatively good
accurately.