Positional Error Estimation in Serial Link Manipulator Under Joint Clearances and Backlash

Abstract

The serial link manipulators are most commonly used for industrial applications. The positional accuracy is an important specification for performance evaluation of a serial chain manipulator. The factors influencing the positional accuracy of serial link robotic manipulator includes joint clearances, and drive backlash. This paper presents method for evaluating the effect of joint error on positional accuracy of the robotic manipulator. Serial chain Two Revolute Joint (2R) planar manipulator is modeled to position the end effector in workspace. The inverse kinematic analysis under ideal joint provides the link properties for respective end effector location. Formulation for manipulator link properties under influence of the joint clearance is presented. Effect of drive backlash on positional accuracy of end effector is analyzed. Positional deviations at end effector positions over workspace are estimated. Maximum error under influence of backlash and clearances is estimated at all possible end effector positions.