Friction Characteristics of a Cylinder Based on a Bridge-Type Pneumatic Energy-saving Circuit

Abstract

A bridge-type energy-saving circuit is a new type of pneumatic system that uses four on-off valves to control the inlet and exhaust of two cylinder chambers. It saves energy through the open-and-close sequence of the four control valves. Cylinder friction is the key factor in accuracy and stability of the bridge-type pneumatic energysaving circuit. This paper focuses on research of the circuit’s friction characteristics. Based on friction theory and the classic Stribeck model, a composite dynamic friction model of a cylinder in a circuit system is established, and a cylinder friction test platform is constructed. The Nelder-Mead algorithm is used to identify static parameters of the model through the relationship between friction and velocity while the piston is moving. Friction model verification with error analysis is achieved by comparison with the traditional friction model. Experiments with the energy-saving circuit under certain conditions are carried out to illustrate the effectiveness of the composite dynamic friction model. Finally, compared with existing friction model, the validity of the model is proved to be applicable to different working conditions.