| Calibration is a necessity for those who operate industrial robots and a cost-effective, time-efficient means of accomplishing this task is highly desired. This thesis describes the development of a calibration procedure for six-axis serial robots where the distinctive feature of the procedure is that it employs the novel Relative Measurement Concept. The main goal of this procedure is to utilize measurements relative to the end-effector of the robot, as opposed to those provided in an absolute fixed coordinate frame. Images of a precision-ruled straight-edge, acquired along its length and focused on the graduations, yield relative measurement of the positioning errors. Robot parameter deviations can then be identified so that the nominal parameters, resident in the robot controller, can be corrected. The objectives of this thesis are to: develop the robot kinematics necessary to compute the forward and inverse kinematics for any six-axis serial robot, develop a procedure capable of using relative measurements, perform a simulation of the procedure, and validate the results through experimentation with a Thermo CRS A465 serial robot. Simulation results are very encouraging and the experimental results lead to the identification of the multiple sources of error corrupting the experimental calibration measurements. |
