Being one of the major robot manufacturers, Kuka Roboter GmbH certainly is the number one supplier of Absolute Accurate Robots. This is mainly due to the wide acceptance of these calibrated Kuka robots at BMW and DaimlerChrysler.
An absolute accurate robot is based on the standard robot, but is individually measured in a high number of poses. The deviations and errors that come out of these measurements are used to build a robot signature. This robot signature is different for each of the robots and predicts all geometrical and flexibility errors in the entire working range. The signature will be used inside the robot controller to make it “absolute accurate”, independent from position or active payload.
Absolute accuracy is one of the necessary steps to limit the difference between the off line simulations and the real production line.
When Kuka was looking at the most appropriate 6D measurement system to measure these calibration poses, lots of criteria had to be taken into account: measurement speed to keep the total calibration time limited, measurement volume, measurement accuracy, user friendliness for the operators, service, price, long term stability, …
For another important criteria we have to look further in the robot lifetime: Like any robot, also absolute accurate robots might require repair or overhaul after crashes. To get the initial absolute accuracy back, these robots might need to be recalibrated after working in the production line. A measurement system should thus also allow recalibration at customer site in the robot workshop or even in the production line!
The Metris K600 measurement system suited these demands perfectly and is now used in seven production cells to calibrate encoder offsets before setting the null marks for the standard robots, to measure the absolute accurate robots in a high number of poses and to perform an outgoing quality control.
Also most of the BMW and DaimlerChrysler robot workshops have seen the interest to be able to recalibrate these robots and are now equipped with a Metris measurement system for robot calibration and performance testing.
For more information about the Metris measurement system for robotics, please contact us at steven.renders@metris.com or visit www.Metris.com
For more information about the Kuka robots, please visit www.kuka.com
