Study On Friction Characteristics Of Pneumatic Cylinders Base On LuGre Model

Recently with the rapid development of microelectronics technology, the pneumatic servo system, especially the pneumatic position servo control system, has become more and more widespread application in many industrial fields. However, the pneumatic servo systems have many disadvantages to be overcome. For example, they have very low stiffness, inherently non-linear behavior and low damping, which cause difficulties to precise control. Among these, the most complex non-linearity in pneumatic position servo systems is the friction force of the actuator, which has a decisive influence on its motion characteristics. So learning more about the friction force in pneumatic actuators is an important step to obtain the precise control and its appropriate design.In this regard, we look at the current research status on the friction of cylinders, and have a comparison of various existing friction models, then briefly analyze the friction factors. On this basis, a new experimental apparatus on which the cylinder tested is driven by a servo motor, is designed to have an in-depth study. The friction of a rodless and a single-rod cylinders are tested under different working pressures and speeds, as an example. And then the method to identify the parameters of LuGre Model using the experiment data is proposed. Also the impact of various pressures on the parameters is investigated. Finally, According to the experimental results, some useful suggestions on how to measure and describe the friction characteristics of the cylinder reasonably and effectively are carried out.The whole paper consists of four sections:Chapter one is the introduction of this paper. It first briefs the current application situation of cylinders, and then briefly introduces the current research status on the cylinder friction. In the end, it points out the main subjects of the research work.Chapter two introduces the theory of friction by tribology method, including a variety of typical friction phenomenon, various existing static and dynamic friction models, and the impact of the friction factors.The third chapter describes in detail the design of test rig on cylinder friction, including its hardware and software design.In the fourth chapter the method to identify the parameters of the friction model is proposed. And then the friction of a rodless and a single-rod cylinders are tested under different working pressure and speed. Also the impact of various pressures on the parameters of the friction model is investigated. Finally, According to the experimental results, some useful suggestions on how to measure and describe the friction characteristics of the cylinder reasonably and effectively are put forward.