Leoni improves machine perception with its calibration system
Presentation at the Hanover Trade Fair: precision laser measuring systems for part unracking, gripper and part location
The challenges during part unracking lie in ensuring that bodywork components are correctly picked from containers and stacks; e.g. bonnets, side and roof panels etc. This is achieved by 6D part location, meaning that both translations and rotations are taken into account during the measurement process. Integrated precision laser or ultrasonic sensors are used in the gripper. The gripping position is adjusted automatically. The system is compact, lightweight, robust and integrated directly in the gripper; it can be easily installed for part picking and retrofitted to the production line without any costly modifications.
In the case of gripper measurement, the system is deployed for precise calibration of grippers or picked components in precision handling. This is frequently required in powertrain applications where engine or transmission parts have to be located. Changes in the gripper or in the part location are detected early and corrected in-line. This avoids collisions and optimises position accuracy.
The challenges in part location lie in ensuring that parts are positioned correctly for processing in such precision applications as handling, welding, sealing or milling. The robot path is automatically corrected according to the part position, thereby ensuring that processing always takes place in the correct location.
6D measurement process
To begin with, the starting point and search direction are defined for the respective part by means of teach-in in the robot programme. The features for the search, e.g. hole centre, edge or curve, are determined, with at least three features having to be localised on the part for 6D measurement. To measure, the robot arm passes the laser beam across the features to be recognised. The height profile of the features is stored by the controller and its position is calculated. A 6D correction is then extrapolated from the localised features and transmitted to the robot control system. The system operates with a laser sensor system that provides reliable results within seconds without any aids or reference pins and even in rough production environments – in-line and fully automatic. Subsequent teaching is unnecessary. Various kinds of laser sensors can be used, depending on the application. The typical measurement time starts from 3 seconds depending on the configuration.
Precision, cost saving, simplicity and short measuring times
The advintec 6D laser measurement system enables the user to make substantial cost savings because this high-precision measuring copes without any aids or reference components. The system presents a very attractive alternative in terms of price; especially in comparison with conventional mechanical systems. Position-related failures or even collisions can be avoided entirely, as can manual programme corrections, because correction of the processing position takes place directly and automatically in the ongoing production process. In addition, the system is particularly easy to integrate and use. It is commissioned by means of the supplied robot programme. The system furthermore has a high tolerance to ambient light, is scalable and can be standardised. Finally, the advintec 6D laser measurement system facilitates an increase in plant uptime as well as quality assurance in production, and all that at a measurement time starting from 3 seconds depending on the respective configuration and application.