Reaction force based grasping position estimation of multi-teleoperated robots for pipe installation in offshore plants

When two robots grasp a long object such as a pipe, each robot needs information on the position of the other robot´s grippers to create a path while handling the pipe. Thus, our study discusses methods of estimating the other robot´s position and angle during a grasping operation by one robot, which is a fundamental pipe-handling technique using for tele-operated robots. For verification of handling a pipe by robot grippers, our experiment is designed with three cases: the grippers of the two robots are separated by the same distance in opposite directions; one robot´s grippers are separated, whereas the other robot´s grippers are fixed; and the grippers of the two robots grasp a pipe that is not laid parallel to the ground. The three cases were tested by using two practical robot grippers and a pipe. Using force/torque sensors installed on the robot grippers, the reaction forces of each robot´s grippers were measured at the location where the pipe was grasped. By comparing and analyzing the measured reaction forces, the estimated relative position and angle between the grippers were described for each case.