Switching Operative Coordinate System Using Intuitive Haptic Device for Alignment of Six-DOF Robot Arm

Robotics teleoperation is useful in various situations. However, when considering the operation of a six-degrees-of-freedom (DOF) robot arm, aligning the six axes for both position and orientation, operations such as the removal of screws become highly challenging, because it is difficult to coordinate the three-DOF position and three-DOF orientation in a way that aligns with human cognitive processes. However, the operational coordinate systems optimal for alignment are different to those for orientation. This study developed a teleoperation system using a custom interface to enable the arbitrary switching of operational coordinates. Comparative experiments were conducted to evaluate the coordinate-switching system. The task of unscrewing was considered because it requires six -DOF alignment. The switching coordinate system significantly reduced the translational movement of the robot arm compared with the tip coordinate system and achieved a decrease of 12% in the average task completion time compared with the base coordinate system. The results reveal that a coordinate-switching system allows for more efficient bolt removal tasks.