含非规则粗糙间隙表面铰链关节的平面柔性多连杆传动系统动态误差与运动副磨损周期行为分析

Analysis of Dynamic Error and Wear Cycle Behavior of Kinematic Pair for Planar Flexible Multi-link Transmission System Including Revolute Clearance Joints with Irregular Rough Surfaces

传统旋转间隙关节接触模型假定销轴和衬套接触面形状是规则的并忽略了磨损效应的影响,降低了机构动力学模型预测精度。提出了一种含非规则粗糙间隙表面铰链关节的平面柔性多连杆机构多体动力学建模、磨损预测和动态误差分析方法。为准确描述运动副元素间碰撞行为,考虑滑动轴承间隙关节的磨损效应,提出了一种非规则粗糙间隙表面铰链关节的改进接触模型。在此基础上,考虑柔性杆的影响,基于绝对节点坐标法建立了含非规则粗糙间隙表面铰链关节的平面柔性多连杆传动系统多体动力学模型。与基于传统光滑间隙模型的结果相比,基于非规则粗糙间隙改进模型的多连杆机构动态响应更接近于试验值,验证了所提出计算方法的有效性。仿真结果表明,选用CuSn10P和CuPb30作为铰链衬套材料能够有效降低多连杆机构滑块动态响应偏差和提高机构的运动精度;表面粗糙度过高会导致运动副磨损加剧,过低则会降低间隙表面微凸体对碰撞能量的吸收。此外,磨损加剧了间隙表面轮廓不规则度,导致机构动态响应的不稳定性增大,运动精度降低。

Traditional contact models of revolute clearance joints consider the contact surface shape of bushing and pin to be regular and neglect the effect of wear, which reduces the prediction accuracy of dynamic model. A method for multi-body dynamic modelling,wear prediction and dynamic error analysis of a planar flexible multilink mechanism including revolute clearance joints with irregular rough surfaces is presented. In order to describe the collision behavior between two elements of kinematic pair, an improved contact model of revolute clearance joint with irregular rough surfaces is proposed considering the wear effect of the sliding bearing clearance joint. Then, with the flexibility of linkage considered, a multi-body dynamics model of planar flexible multi-link transmission system with including revolute clearance joints with irregular rough surfaces is developed using the absolute nodal coordinate method.Compared with the results based on the traditional models with regular smooth surfaces, the dynamic responses of the multi-link mechanism based on the improved model agree better with experimental data, which verifies the validity of the proposed method. The simulation results show that CuSn10P and CuPb30 are selected as the material of bushing in the revolute clearance joint, which can reduce the slider’s dynamic response deviations of the multi-link mechanism and improve its motion accuracy. Too high surface roughness will increase the wear of kinematic pair, while too low surface roughness will reduce the absorption of collision energy due to the asperities on the bushing surface. In addition, wear aggravates the irregularity of the bushing surface profile, which increases the instability of the dynamic response for the multi-link mechanism and reduces the corresponding motion accuracy.