2022–2023 Maeda Lab, Yokohama National University
Caging and Caging-based Grasping
Caging is a method to constrain objects geometrically so that they cannot escape from a “cage”
constituted of robot bodies.
3D multifingered caging While most of related studies deal with planar caging, we study three-
dimensional caging by multifingered robot hands (Fig. 9). Caging does not require force con-
trol, and therefore it is well-suited to current robotic devices and contributes to provide a variety
of options of robotic manipulation. We are investigating sufficient conditions for 3D multi-
fingered caging and developing an algorithm to plan hand motions for caging based on the
conditions [1]. Robot motions generated by the developed planning algorithm were validated
on an arm-hand system [2] (Fig. 10).
Caging-based Grasping Position-controlled robot hands can capture an object and manipulate
it via caging without force sensing or force control. However, the object in caging is movable in
the closed region, which is not allowed in some applications. In such cases, grasping is required.
We proposed a new simple approach to grasping by position-controlled robot hands: caging-
based grasping by robot fingers with rigid parts and outer soft parts. In caging-based grasping,
we cage an object with the rigid parts of a robot hand, and construct a complete grasp with
the soft parts of the hand. We are studying the formal definition of the caging-based grasping
and concrete conditions for caging-based grasping in planar and spatial cases. Based on the
derived conditions, we demonstrated planar caging-based grasping by mobile robots and spatial
caging-based grasping by a multifingered hand (Fig. 11) [3][4]. We also extend the theory of
caging-based grasping so that it can deal with deformable objects (Fig. 12) ([5]).
References
[1] S. Makita and Y. Maeda: 3D Multifingered Caging: Basic Formulation and Planning, Proc. of 2008
IEEE/RSJ Int. Conf. on Intelligent Robots and Systems (IROS 2008), pp. 2697–2702, 2008.
[2] S. Makita, K. Okita and Y. Maeda: 3D Two-Fingered Caging for Two Types of Objects: Sufficient
Conditions and Planning, Int. J. of Mechatronics and Automation, Vol. 3, No. 4, pp. 263–277, 2013.
[3] Y. Maeda, N. Kodera and T. Egawa: Caging-Based Grasping by a Robot Hand with Rigid and Soft Parts,
Proc. of 2012 IEEE Int. Conf. on Robotics and Automation (ICRA 2012), pp. 5150–5155, 2012.
[4] T. Egawa, Y. Maeda and H. Tsuruga: Two- and Three-dimensional Caging-Based Grasping of Objects
of Various Shapes with Circular Robots and Multi-Fingered Hands, Proc. of 41st Ann. Conf. of IEEE
Industrial Electronics Soc. (IECON 2015), pp. 643–648, 2015.
[5] D. Kim, Y. Maeda and S. Komiyama: Caging-based Grasping of Deformable Objects for Geometry-
based Robotic Manipulation
, ROBOMECH J., Vol. 6, 3, 2019.
Fig. 9 3D Multifin-
gered Caging
Fig. 10 Caging of a
Sphere
Fig. 11 Caging-
based Grasping by a
Multifingered Hand
Fig. 12 Caging-
based Grasping of a
Deformable Object
5