Opening Doors With A Mobile Manipulator Without Force-Torque Feedback

Mobile Robots with manipulators are more and more used as instruments of civil protection, for defusing bombs or their disposal. For such vital tasks, these robots are mostly teleoperated by a human expert, but some assistance functions can help the operator in uncritical tasks and reduce the burden of controlling manipulators with many degrees of freedom (DOF). Most urban buildings made for humans are entered or exited through doors. In order to move effectively in such environments, a robot has to be able to pass doors, too, even if they are closed. Opening doors is a very difficult task for an operator of a robot, as it involves many subtasks (e.g. finding the door handle, grasping the handle and pressing it down correctly, moving on circular paths). We developed assistance functions that open a door without the use of sensors, that are often not available for mostly teleoperated robots. Manipulators of bomb defusing robots often do not have force or torque sensors, because they were designed for teleoperation. The operator specifies the door geometry in a 3D environment model. Then, the necessary trajectories are generated by our algorithms and followed by the manipulator to open the door.