Collaboration concept and HRI safety measures – by Sapienza University
|A collaborative human-robot task is performed with a Universal Robots UR10, mounting an ATI mini45 6D F/T sensor and without any other external sensing|
The control algorithm distinguishes external torques acting at the robot joints in two components, one due to (polishing) forces applied at the end-effector level, the other due to intentional physical interaction engaged by the human. When the human operator exerts a pushing force (emulating manual polishing of a part held by the robot), the end-effector tool tip is kept in the working position and orientation under high-gain control. To change the orientation of the part mounted on the robot, the user simply pushes or pulls the robot body and changes thus its configuration. The controller recognizes the situation and keeps instead the position of the work piece fixed. Thanks to the decomposition, the two operations can be done also simultaneously.
Reference: C. Gaz, E. Magrini, A. De Luca, ”A model-based residual approach for human-robot collaboration during manual polishing operations,” submitted in revised form to IFAC Journal of Mechatronics, January 2018.
|Collaboration concept and pHRI safety measures|
A collaborative human-robot task performed with a Universal Robots UR10 monitored by a Kinect, but without the use of a F/T sensor. A hand gesture activates the collaboration and the robot stops. The end-effector tool tip is kept then in the working position and orientation under high-gain position control, while the human operator is exerting a pushing force (emulating the force exerted for manual polishing of a part held by the robot).
|Collaborative human-robot task with a KUKA LWR4 robot|
A collaborative human-robot task performed with a KUKA LWR4 robot mounting an ATI 6D F/T sensor and monitored by a Kinect. A hand gesture activates the collaboration and the robot stops. The end-effector tool tip is kept then in the working position under high-gain position control while the human operator is exerting a pushing force (emulating the force exerted for manual polishing of a part held by the robot). The human can push the robot structure at any other point, so as to achieve a reconfiguration of the manipulator: the end-effector orientation changes, but not the tool tip position (this mimics the need to polish a different side of the part held by the robot). This can be done also when pushing at the same time on the tool tip, which continues to keep its position. This selective behaviour is obtained thanks to the use of our residual-based method to estimate contact forces, which includes now also the F/T sensor measurement of forces applied at a known contact point (the tool tip).