Robot accuracy and stiffness—An experimental study

Investigations in robotics have been mainly directed toward the design of robots with a significant degress of intelligence, capable of high adaptability. However, very little research has been done on the design of a robot manipulator as an executive mechanism of the intelligent control system, whose high quality design will allow the sophisticated functions imposed by the control system.

Experimental investigations of robot accuracy show unacceptable results which limit their future wider application. This is the reason why the off-life programming of robots has not been widely used, without which it is impossible to imagine a more significant integrationof robots in the CIM environment.

The object of our study has been to find out the causes of low degreee of robot accuracy, emphasizing the non-corresponding choice of the robot coordinate system, algorithmic and computational errors and drive and transmission element design. Comparison with corresponding results gained from investigations of CNC machine tools cannot be avoided because of the fact that robots are also machines from which accuracy is required. What is missing in robotics today, but which inevitably is required, is the establishment of a standard methodology for testing robot accuracy and other performance.