Friction Model And Simulation In Mechanical System

Friction exists in almost all-mechanical system. The phenomena such as steady-state error, and limit circle have already become a serious obstacle that impedes the efficiency of the system. Therefore, the research on dynamics of mechanical system with friction is becoming a hot issue in the current times.In this thesis, first, based on the physics characteristic of friction and the latest research achievements on friction modeling, the reason for friction phenomena is explained. By analyzing the established simple physical model, the reason and influence factors for creeping are obtained, At last, the advantages and disadvantages of friction models developed in the recent years are discussed,The numerical simulation on Lurge models is performed using MATLAB, based on which, the observed phenomena of non-linear friction such as pre-sliding displacement, frictional lag, varying break-away friction and viscous sliding phenomena are simulated and discussed. Meanwhile, the influences of the Lugre friction model parameter on the second-order system response are analyzed.The parameter identification of Lurge friction model is carried out by means of two steps procedure. In the first step, four static parameters are identified from the Stribeck curves. In the second step, the two dynamic parameters are identified from the pre-sliding response. In the above two steps, the non-linear least squares method and genetic algorithm are applied to search the optimum.Finally, a PD-controlled single degree of freedom motion system with the Lurge friction model and driven by DC motor is simulated.