Kinematic Calibration of the Hexaglide Parallel Robot Using a Simple Measurement System

Because of errors in the geometric parameters of the parallel robots, it is necessary to calibrate them to improve the positioning accuracy for accurate task performance. Traditionally, to perform system calibration, one needs to measure a number of robot poses using an external measuring device. However, this process is often time-consuming, expensive and difficult for robot on-line calibration. In this paper, a methodical way of self-calibrating of Hexaglide parallel robot is introduced. This method is performable only by measuring input joint variables and errors of positioning relative to the desired position in some sets of configurations where in each set the desired position is fixed, but orientations of the moving platform are different. In this method, measurements are relative, so it is performable by using a simple measurement device. Simulations give us an idea about the number of desired points, the number of orientations in each point and the effect of noise on the calibration accuracy.