Abstract:Piecewise linear friction in the joints is often used to model dynamic behavior of robot arms. Nonlinear friction has been, however, found as one of the key factors to determine the dynamic jitter trajectory of robot arm tips. It is studied that the nonlinear friction model of the robot joints and its influence on the dynamic trajectory of robots. A kinematic model is established for multi-joint robots, using which the angular displacement, velocity and acceleration of joints are

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... ed for any planned trajectory. The Newton-Euler inverse dynamics analysis is then carried out to find out the forces and torques at the joints considering nonlinear frictions, for a given trajectory at the arm-tip. These forces and torques are substituted applied into the forward dynamics model to obtain the actual trajectory of the arm-tip. Using our analysis procedure, the influence of different driving torques on the trajectory and the angular displacement of each joint are studied in great detail. The results show that the nonlinear friction has a significantly influence on the trajectory of the arm-tip. The present forward and inverse dynamic analysis procedure and the nonlinear friction model proposed in this work provide a useful analytic and modeling tool for the development of high-precision robots. Keywords:robot arm;nonlinear friction model;dynamic modeling;Newton-Euler methods;forward-inverse dynamics;robot arm kinematics;motion trajectory * 国家重点研发计划(2017YFB1301300) 和国家自然科学基金青年基金 (11902110)资助项目。20190528 收到初稿,20190925 收到修改稿 月 2020 年 5 月 段书用等:机械臂动力学分析及关节非线性摩擦模型建立 19