Friction Model Identification for Dynamic Modeling of Pneumatic Cylinder

Friction is one of the main nonlinear properties that makes pneumatic actuators difficult to control and reduces their energy efficiency. Many phenomenological friction models are used to describe pneumatic cylinders dynamic behavior, including in pre-sliding zone. These models maintain many unknown empirical parameters (maybe 7 or more). Expensive test equipment and special mathematical methods are required to define the parameters of friction model. But the results may vary significantly for one size cylinders of various manufactures. This paper presents the results of determination the Stribeck friction model parameters based on limited experimental data and procedure of vector identification which implemented in the software complex MOVI (Multicriteria Optimization and Vector Identification). Results were obtained for two types of piston seals materials: NBR and PTFE composite. The minimal value of the piston stable speed for single action cylinders with these seals was estimated.