Precise Robot Calibration Method-Based 3-D Positioning and Posture Sensor

This article presents a distance accuracy technique for zero-offset industrial robot calibration based on 3-D positioning and posture (3DPP) sensor along with modified Denavit–Hartenberg (MDH) for robot kinematics identification. Industrial robots’ distance and positioning accuracy tend to diminish rapidly due to repetitive tasks and heavy loads. Many aspects can be involved in reducing the distance and positioning accuracy of the industrial robot; therefore, using the proper sensors and identification methods is essential to increase or restore the accuracy back to the original state. Normally, maintenance requires apparatus made specifically for robot kinematic calibration which are costly, time-consuming, and must be done by trained operators, while traditional calibration techniques suffer from cumulative error between the calibration device coordinates and robot coordinates. In this article, a 3DPP measurement device and MDH robot kinematic identification method is proposed for a six-degree-of-freedom (6DOF) industrial manipulator calibration, and a distance error calibration model is applied. The results indicate that the proposed 3DPP sensor and calibration model based on MDH improved the absolute position accuracy and distance accuracy greatly, the positioning maximum and average error were reduced by 94% and 96% respectively, and the distance maximum and average error were reduced by 95% and 96% respectively. The experimental results confirm the efficiency of the sensor and proposed method.