Loading and Unloading of Pallets Using Sensor-Assisted Industrial Robots

Abstract The loading and unloading of pallets is a common problem in the field of component handling. Alternative automation possibilities are shown, and boundary conditions to be observed in the use of industrial robots for this application, as well as drawbacks as compared with other automation devices are discussed. The demands placed upon a palletizing robot regarding the kinematic construction, the control and the peripherals are determined. The efficiency of robots is compared with that of other alternative solutions. To ensure the operational reliability of the overall system, apart from the actual handling process sensor problems have to be mastered. The problem-related scope of sensor requirements are defined. Various sensor principles are assessed with regard to their suitability. Position recognition of pallets and of the objects placed thereon is an essential task for the sensors. Test results from various sensors for this problem area are discussed, whereby above all the arrangement of the sensors is important. In the investigations and practical experiments carried out, ultrasonic distance measuring systems as well as reflected-light barriers proved to be particularly suitable. Further developments are to lead to the implementation of sensor systems on palletizing robots, whereby signal evaluation strategies and the robot control software are of foremost interest.