Industrial robot calibration method using denavit — Hatenberg parameters

Robotic manipulators have been used widely in industrial applications such as assembly and machining operations. To perform these operations precisely, the robots must possess good accuracy and repeatability. For that reason, all the industrial robot manufacturers and users are focused on the performance test of the robots using laser tracker. However, robot calibration is needed to precisely align the robot to the sensor and the world coordinate system to get accurate data of the accuracy. It also useful to identify an accurate kinematic robot model. The general idea of calibration is to measure n points in space while storing the joint data for each measured point. Using the joint data the forward kinematics can be calculated to obtain a target position of the robot. The calibration algorithm them starts tweaking the kinematic parameters of the robot such that the measured points are optimally fit the points provided by forward kinematics.