Investigation into the Influence of Link Dimensional Errors on the Positioning Accuracy of a Four-Degree-of-Freedom SCARA Robot

The SCARA (Selective Compliance Assembly Robot Arm) is a four-degree-of-freedom robot widely used in microchip assembly and placement processes, thanks to its high flexibility in the horizontal plane. The positioning accuracy of the robot's end-effector directly determines the quality of the assembled products. This paper presents a study evaluating the influence of link dimensional manufacturing errors on the positioning accuracy of the SCARA robot gripper. The mathematical relationship is established using the Denavit-Hartenberg (D-H) homogeneous transformation matrix method and total differentiation. Numerical simulation results in MATLAB indicate the error contribution level of each individual link to the final position error. This research provides an important database to help designers allocate manufacturing tolerances rationally and optimize robot production costs.