Experimental and analytical investigations of friction at lubricant bearings in passive suspension systems

摘要

Friction is a very complex phenomenon, arising from the contact of surfaces. In many engineering applications, the success of models in predicting experimental results remains strongly sensitive to the friction model. In practice, it is not possible to determine an exact friction model; however, based on observation results and dynamic systems analysis, a recently proposed model of nonlinear friction at linear supported lubricant bearings is investigated. This model involved static friction, stiction region, and dynamic friction, which is consisted of transition, Stribeck effect, Coulomb and viscous frictions. On the other hand, this model is applied in the passive suspension system. Accordingly, a new quarter-car passive suspension model with the implementation of friction force is considered. Also, a vital experimental and simulation aspect is the generation of system input. Therefore, a nonlinear hydraulic actuator used, modelling this actuator including the dynamic of servovalve derived by the proportional-integral (PI) controller, is prepared. This study is validated experimentally, with simulation achieving C++ compiler. Consequently, a good agreement between the experimental and simulation results is obtained, i.e., the nonlinear friction, passive suspension system and nonlinear hydraulic actuator models are entirely accurate and useful. The suggested PI controller successfully derived the hydraulic actuator to validate the control scheme.