High-Speed, Small-Deformation Catching of Soft Objects Based on Active Vision and Proximity Sensing

In this letter, we propose a combination of sensing and control modules for catching soft objects (i.e., a marshmallow and paper balloon) at a high speed with small deformation. A paper balloon and marshmallow are deformed by a small force and they have individual differences in terms of softness. Therefore, model-based, small-deformation catching is difficult. To realize small-deformation catching, we used high-speed sensor-based (vision and proximity) control modules without a deformation model of the soft objects. A high-speed vision-based controller adjusts the positions of the fingertips of a robot to some extent. As the distance to the object decreased, the fingertip positions were accurately controlled by the high-speed, high-precision proximity-based control. Furthermore, the fingertips were stopped by a proximity-based contact detection before the object surface was deformed. Virtual damping control was effective in catching an object whose surface can be easily deformed by a small impact force or vibration of the fingertips, such as a paper balloon.