Accuracy assessment of the modern industrial robot

The main drawback to programming robots off line lies in the poor accuracy of the robot. Robots are mainly programmed using the traditional teach and repeat method of programming which requires only good repeatability. As a result robots are manufactured with this in mind. Little is done to improve or even quote figures for the accuracy, which is generally regarded as being poor. A trial has been conducted on three modern serial linkage robots to assess and compare robot accuracy. Using a laser interferometry measurement system each robot has been measured in a similar area of its working envelope. The results and conclusions from this trial show that compared to older robots the accuracy can be remarkably good though it is dependent on a calibration process which is far from robust.