Nonlinear dynamic behaviors of electro-hydraulic servo system under friction

With electro-hydraulic servo system as the research object,the influence laws of nonlinear friction on system dynamic characteristics were explored. Based on the principle of the nonlinear dynamics,the nonlinear dynamical model of system was established. Then,a conclusion was put forward that the effect of nonlinear friction could be described by Van Der Pol equation. The bifurcation phenomenon and typical nonlinear dynamical behaviors which implied within the system were revealed through numerical experimental analysis. Moreover,with the nonlinear dynamics methods,the measured dynamic data were thoroughly analyzed. And the "limit cycle oscillation"phenomenon caused by friction was revealed. The results indicate that the nonlinear effect of friction can cause nonlinear vibration occurred in system working process. The influence of friction on system dynamic characteristics cannot be ignored. The nonlinear effect of friction should be taken into account in system modeling and dynamic characteristics research.