ass日本风韵熟妇pics男人扒开女人屁屁桶到爽|扒开胸露出奶头亲吻视频|邻居少妇的诱惑|人人妻在线播放|日日摸夜夜摸狠狠摸婷婷|制服 丝袜 人妻|激情熟妇中文字幕|看黄色欧美特一级|日本av人妻系列|高潮对白av,丰满岳妇乱熟妇之荡,日本丰满熟妇乱又伦,日韩欧美一区二区三区在线

The kinematics of a 4-SPS/CU parallel mechanism was analyzed. In order to quantitatively analyze the influence of joint friction acted as non-conservative force on the mechanism dynamics, the calculation of the normal force corresponding to joint friction was important. For simplifying the dynamics model, the driving chain was treated as a rigid body so the driving friction could be seemed as internal force. Based on the “Coulomb + viscous” friction model, the dynamics model with joint friction of up platform, driving chain and driven chain were built respectively by using Newton-Euler formulation, which could obtain the joint constraint forces/torques with giving motion trajectory of the mechanism’s up platform. Subsequently, the driving friction models were established on account of the relationship between the driving chain’s normal forces and joint constraint reactions. The iterative procedure of complicated dynamics equations was formulated for the effective simulation. The research results showed that joint friction forces significantly impacted on the driving forces of the mechanism.