Nonlinear Dynamic Characteristics Analysis of Planar Mechanism Multibody System Considering Lubrication Clearances

Due to various factors, there will inevitably be clearance in the mechanism. The clearance can reduce the accuracy and stability of mechanism, while lubrication effectively improves this situation. Previous researches mainly centered on mechanism with dry friction clearance, but less on complex mechanism with lubrication clearance. Moreover, previous researches mainly centered on dynamic response of mechanism, while less on nonlinear characteristics of mechanism. To research the impact of lubrication clearances of mechanism, nonlinear dynamic characteristics of nine-bar mechanism multi-body system are studied. Lubrication force model is established by modified Pinkus–Sternlicht model. Dynamic model of mechanism with lubrication clearances is established by Lagrange multiplier method. The experimental platform of the mechanism is built, and correctness of theoretical model is verified by experiments. This paper analyzes the influence of dry friction clearances and lubrication clearances on output response of mechanism. The influence of clearance value, lubrication viscosity and driving speed on dynamic response are analyzed. The influence of clearance value and driving speed on nonlinear characteristics of mechanism are analyzed by means of Poincare mapping, phase and bifurcation diagram. The research provides theoretical references for prediction and control of dynamic performance for mechanism with clearance.