A robotic hand performing a scooping grasping motion — something you probably haven't seen often.
When humans pick up an object from the floor, we naturally use a scooping motion to lift and grasp it. However, controlling this motion is extremely challenging for grippers or robotic hands with rigid fingertips. Even with direct human teleoperation, managing contact with the environment remains difficult.
While using soft fingertips is an alternative, it inevitably comes with a trade-off: a loss of grasping force and positional accuracy.
💡 Our research team has solved this problem using fingertip sensors attached to the AIDIN Robotics hand. By utilizing the external forces generated when the finger makes contact with the environment, we successfully achieved a seamless scooping grasping motion.
Through this approach, the kinematic joints of the finger avoid forming a closed-loop chain with the environment upon contact, enabling safe interaction against external constraints.
Scooping grasping motion achieved via fingertip force sensing on AIDIN Robotics hand.
Fingertip force-torque values are transformed to the wrist frame and combined with the wrist F/T sensor for compliance control of the manipulator.
Each fingertip wrench \(\mathbf{w}_i = (\mathbf{f}_i,\, \boldsymbol{\tau}_i)\) measured in the fingertip frame is transformed to the wrist frame \(\{W\}\) via the kinematic transform \({}^W T_i\). The rotation matrix \(\mathbf{R}_i\) and position offset \(\mathbf{r}_i\) are obtained from TF.
The aggregated wrench at the wrist combines all \(N\) fingertip contributions and is merged with the physical wrist F/T reading \((\mathbf{f}_\text{wrist},\,\boldsymbol{\tau}_\text{wrist})\):
This combined wrench \((\mathbf{f}_\text{total},\, \boldsymbol{\tau}_\text{total})\) is fed as the external force input to the impedance controller, enabling the manipulator to react compliantly to both wrist-level and fingertip-level contacts during the scooping grasping motion.
Without the aggregator, the manipulator cannot react sensitively to floor contact. With the aggregator, the combined fingertip wrench enables immediate compliant response.
Click on any video to play both simultaneously.