Now industrial robots are typically able to move with best positional accuracy. The accuracy of the robot can be asserted by measuring the position and orientation of robots. In order to achieve the best absolute accuracy, manufacturers usually offer a calibration. This work deals with inverse kinematic analysis of robot manipulator by using Denavit-Hartenberg (DH) parameters and also presents a methodology for finding geometric error using an error model based on all DH parameters. One of the sources of error in robots is the changes in DH parameters. Such as Joint angles, link lengths, offset distances and twist angles. In this work, DH parameters are optimized by using Jacobian approach. For a particular pose the minimum or required error at the end effector can be achieved through iterations. It can be inferred from the analyzed variations of DH parameters through the error model that, Variations in the DH parameter values for the poses are minimal and Variations in joint angles are least compared to other three DH parameters. SCORA ER14 Robot is used for the analysis. These errors have been compensated by incorporating in the robot controller, and the controller performance is analyzed through the help of numerical simulations.

Keywords:Robot manipulator, Denavit-Hartenberg parameters, Kinematic error model, Jacobian, Robot control.