Highly Efficient Control System Enabling Robot Accuracy Improvement

A significant challenge when using industrial robots as flexible handling devices - for example in the area of creating miniaturized conductive patterns on three dimensional molded interconnect devices - is their relatively low absolute accuracy, which is caused by inaccuracies in the robots kinematic chain. This characteristic has to be considered, especially if complex and precise 3D-movements are needed. One approach to overcome this problem investigated at FAPS is the usage of a specially designed robot control system with parallel data processing for real-time correction value determination and usage of these values for remote control of a robot to improve its accuracy. The developed control system utilizes existing network technologies and uses data of sensor systems for continuous process monitoring to derive the robots actual state in course of its movement. In case of a high speed camera the image data is acquired by the control system via a first thread and subsequently the actual robot position is calculated based on this data. At the same time, for determining the robots target state, the system continuously requests the robots nominal position from the robot controller by utilizing a parallel second thread. The information describing the robots actual state is then compared with the sensor data for calculating offset values. These offset values are subsequently filtered and a correction value is calculated. In a third parallel thread new movement instructions are generated, considering the offset values as well as the robots target trajectory. Finally, for remote control of the robot, these movement instructions are transferred to the robot controller. (C) 2014 Elsevier B.V.