Position and Force Control of a Translation/Rotation-Decoupled Direct-Drive Robot Using Visual Feedback.

Abstract

In this paper, a method for acquiring trajectory information from the object of task through a vision sensor to generate reference trajectory to a robot control system is proposed. The trajectory generation is done online and "on-task" (during the execution of the task). The whole image acquired from the vision sensor is processed to get the relevant trajectory data, taking considerable computation time if compared with the computation time of a robot control system. Making use of the preview characteristic of the vision information, a method for the synchronization of the image processing system and the robot control system, implemented separately, is proposed. This synchronization method allows the application of the proposed system in image pocessing systems with low frame rate. The proposed method is experimentally verified by applying it to a force and position control system of a translation/rotation-decoupled direct-drive (DD) robot, of which the generation of the desired trajectory is not a trivial task. The image processing is performed on images grabbed from a CCD camera installed on the robot arm and the desired trajectory is generated online.