# Research of Calibration Method for Industrial Robot Based on Error Model of Position
## 1 Introduction
However, the user needs to have relevant measurement skills, and the measurement results are easy to be interfered by environmental factors. In reference [14], the robot of IRB2400 was calibrated with a laser tracker. In this application, the base coordinate was obtained by means of making axis 1 and axis 2 rotate, respectively, and measuring the base plane, so that the coordinate transformation can be realized between laser tracker and robot base. Reference [15] uses the FARO ARM to calibrate the robot and obtain the RBCS by quaternion form. [PERSON] [16] used Faro laser tracker to measure and calibrate ABB IRB1600 (ABB, Zurich, Switzerland) industrial robot from Switzerland. The mean absolute positioning accuracy can be reduced from 0.981 mm to 0.292 mm in eight different measurement points on the robot end effector. The measurement of the equipment is very accurate, and it can further cooperate with other relevant tools to obtain the target attitude. The equipment is easy to operate, but it is very expensive. In addition to use the above measuring instruments to directly measure the absolute pose of the end of the robot for calibration, some scholars have studied the robot self-calibration method of indirectly measuring the pose of the end of the robot through the algorithm without relying on the measuring instruments. [PERSON] [17] proposed a closed-loop self-calibration method, which kept the end of the robot at a point unchanged, and changed the pose of the end of robot, so as to finally solve the closed-loop equation. [PERSON] [18] used multi-plane constraints to calibrate the six axes flexible robot. [PERSON] [19] used corded sensor to measure the position and pose of the robot and complete the calibration of the kinematic parameters of the robot. However, in the existing robot calibration and measurement process, the pose errors of the robot caused by base coordinate system and FCS are neglected basically, which is also an important part of the robot pose error model and should be considered in the process of robot calibration, and this part of the error cannot be improved only depending on optimizing the motion algorithm of the manipulator. The absolute positioning error must be measured by a measuring instrument and then improved by the algorithm. The robot's calibration can be achieved by establishing the robot's position error model or pose error model. Since most measuring devices can measure the position of the end of the robot, the position error model is more suitable for a wide range of measuring devices (such as coordinate measuring machine, six or seven axes measuring arm, laser tracker (with a target ball)). It is more versatile. This paper aims to enhance the APA of the robot. The measurement hidden errors from the robot's flange and base coordinates and the kinematics model parameters errors are unified as the source of the absolute positioning errors. A comparatively general measurement method of robot calibration is proposed, and the algorithms of parameter error identification and compensation are discussed in detail. The algorithms are verified by experiments.