End-effector accuracy and reliability analysis for robotic manipulators with lubricated clearance joint

End-effector accuracy and reliability of the robotic arm is greatly affected by the joint error, and the different joint clearance reflects the interaction between the local and global error, which is the basis for the design reliability of the robot. At present, most research has focused on the kinematic accuracy of the robotic arm, and few have focused on the dynamic response error and accuracy reliability including clearance joint without lubrication. In this paper, a method for analyzing the dynamic response error and accuracy reliability of the robotic arm with lubrication clearance joint is proposed. Firstly, the dry contact and lubricated clearance joint were modeled respectively, and a six-degree-of-freedom robotic dynamic model with multiple lubrication clearance joints was developed using the Lagrangian multiplier method. Then, the first-order second-moment method is used to calculate the dynamic accuracy reliability of the robot. Finally, the effects of different clearance sizes, locations, and lubricating oil viscosities on the dynamic response error and accuracy reliability of the robot were compared and analyzed. This research demonstrates the potential to improve the stability and service life of the robotic arm, as well as the reliability design.