Dexterous manipulation with compliant grasps and external contacts

Abstract

Abstract-We propose a method that allows for dexterous manipulation of an object by exploiting contact with an external surface. The technique requires a compliant grasp, enabling the motion of the object in the robot hand while allowing for significant contact forces to be present on the external surface. We show that under this type of grasp it is possible to estimate and control the pose of the object with respect to the surface, leveraging the trade-off between force control and manipulative dexterity. The method is independent of the object geometry, relying only on the assumptions of type of grasp and the existence of a contact with a known surface. Furthermore, by adapting the estimated grasp compliance, the method can handle unmodelled effects. The approach is demonstrated and evaluated with experiments on object pose regulation and pivoting against a rigid surface.

Dual-Arm In-Hand Manipulation and Regrasping Using Dexterous Manipulation Graphs

“…An additional support that enhances the dexterity, other than gravity, friction and inertial forces, is the use of external contacts with other surfaces [28]- [30]. The presence of external contacts helps in manipulating the object and allows the robot to reorient it and obtain the desired pose.…”

Benchmarking In-Hand Manipulation

“…Some of these works exploit gravity and inertial forces to initiate the motion of the object [30], [34]- [37], while others rely on pushes against an external contact. This contact can be either a fixture or a surface present in the environment [9], [38], [39], or a second gripper in a dual-arm manipulation scenario [10].…”

Discrete Bimanual Manipulation for Wrench Balancing

“…We consider robots equipped with parallel grippers, which are non-dexterous in nature. Such grippers can execute dexterous manipulation tasks by leveraging extrinsic dexterity [17]; extrinsic dexterity is the exploitation of supports external to the gripper, such as additional contact surfaces [18]- [20], gravity and friction [21], to compensate for the lack of degrees-of-freedom of the grippers. As external support, we exploit the redundancy of the dual-arm system to enable motions of the gripper along the tray without releasing the grasp: while one gripper moves, the other keeps a tight grasp on the tray so that the gripper's fingers can slide along its surface without affecting its pose.…”