In-Hand Sliding Regrasp With Spring-Sliding Compliance and External Constraints

Abstract

We investigate in-hand regrasping by pushing an object against an external constraint and allowing sliding at the fingertips. Each fingertip is modeled as attached to a multidimensional spring mounted to a position-controlled anchor. Spring compliance maps contact forces to spring compressions, ensuring the fingers remain in contact, and sliding ''compliance'' governs the relationship between sliding motions and tangential contact forces. A spring-sliding compliant regrasp is achieved by controlling the finger anchor motions. We derive the fingertip sliding mechanics for multifingered sliding regrasps and analyze robust regrasping conditions in the presence of finger contact wrench uncertainties. The results are verified in simulation and experiment with a two-fingered sliding regrasp designed to maximize robustness of the operation.

In-Hand Object-Dynamics Inference using Tactile Fingertips

“…Given knowledge of object dynamics, robots can perform accurate and robust multi-contact manipulation of modeled objects via physics-based planning and control [11][12][13][14][15][16][17][18]. Physically realistic simulation could also benefit from realworld object dynamics knowledge to train policies in simulation that robustly transfer to real systems.…”

“…Apart from inertial parameters, friction also plays an important role in contact-based object interaction such as in grasp planning via force-closure optimization [33] and sliding based in-hand manipulation [17]. Empirical studies of planar manipulation have also shown friction to play a key role in how objects react to contact [16,34].…”