摘要
The collision and wear caused by inevitable clearance in kinematic pair have an effect on the dynamic characteristics of the mechanism.Therefore,we established the dynamic model of a 3RSR(R is the revolute joint and S is the spherical joint)parallel mechanism with spherical joint clearance based on the modified Flores contact force model and the modified Coulomb friction model using Newton-Euler method.The standard quaternion was introduced in the constraint equation,and the four-order Runge-Kutta method was adopted to solve the 3RSR dynamic model.The simulation results were compared and analyzed with the numerical results.The geometrical parameters of the worn ball socket were solved based on the Archard wear model,and the geometrical reconstruction of the worn surface was carried out.The geometric reconstruction parameters were substituted into the dynamic model,which was to analyze the dynamic response of the 3RSR parallel mechanism with wear and spherical joint clearance.The simulation results show that the irregular wear occurs in the spherical joint with clearance under the presence of the impact and friction force.The long-term wear will increase the fluctuation of the contact force,thereby decreasing the movement stability of the mechanism.
运动副难以避免地存在间隙,间隙的存在将引起碰撞与磨损,而运动副间隙和磨损会影响机构动力学特性。考虑3RSR(R为转动副,S为球副)并联机构中球副间隙,基于改进的Flores接触力模型和修正的Coulomb摩擦力模型,利用牛顿-欧拉法建立机构的动力学模型,引入标准四元数搭建约束方程,并采用四阶Runge-Kutta法进行求解,将仿真与数值求解结果进行分析对比。基于Archard磨损模型,求解磨损球窝的几何参数,利用其对磨损的表面进行几何重构,并将几何重构参数代入动力学模型,分析考虑磨损特性的含球副间隙3RSR并联机构的动力学响应。仿真结果表明,在冲击力和摩擦力存在的情况下,球副出现不规则磨损,长期磨损会增加接触力的波动,从而降低机构的运动稳定性。
作者
HOU Yu-lei
DENG Yun-jiao
ZENG Da-xing
侯雨雷;邓云蛟;曾达幸(School of Mechanical Engineering,Yanshan University,Qinhuangdao 066004,China;School of Mechanical Engineering,Dongguan University of Technology,Dongguan 523015,China)
基金
Project(2018YFB1307900)supported by the National Key R&D Program of China
Project(51775473)supported by the National Natural Science Foundation of China
Projects(E2018203140,E2019203109)supported by the Natural Science Foundation of Hebei Province,China
Project(ZD2019020)supported by the Key Research Project in Higher Education Institutions of Hebei Province,China
Project(2017KSYS009)supported by the Key Laboratory of Robotics and Intelligent Equipment of Guangdong Regular Institutions of Higher Education,China
Project(KCYCXPT2017006)supported by the Innovation Center of Robotics and Intelligent Equipment of Dongguan University of Technology,China。
