arXiv subjects

Nicholas Gravish

Publications and source records attributed to Nicholas Gravish.

3 recordsLinked to original sources

arXiv2026

Interdisciplinary Workshop on Mechanical Intelligence: Summary Report

This report provides a summary of the outcomes of the Interdisciplinary Workshop on Mechanical Intelligence held in 2024. Mechanical Intelligence (MI) represents the phenomenon that novel structural features of material/biological/robotic systems can encode intelligence through responsiveness, adaptivity, memory, and learning in the mechanical structure itself. This is in contrast to computational intelligence, wherein the intelligence functions occur through electrical signaling and computer code. The two-day workshop was held at NSF headquarters on May 30-31 and included 38 invited academic researcher participants, and 8 program officers from the NSF. The workshop was structured around active small and large group discussions in groups of 4-5 and 9-10 with the goal of addressing topical questions on MI. Working groups entered notes into shared presentation slides for each discussion session and presented their outcomes in a final presentation on the last day. Here we summarize the overall outcomes of the workshop.

cs.RO↗

arXiv2026

Three phases of odd robotic active matter

Nonreciprocal interactions in active matter are known to generate exotic mechanical behaviors such as odd elasticity and odd viscosity. However, these phenomena have largely been studied in isolation, raising a fundamental question: Is there a single system that embodies these distinct regimes of odd matter and can transition between phases, establishing a unified phase diagram for nonreciprocal active matter? To address this, we introduce a tunable robotic active matter platform, the Magnetomechanically Augmented Spinning roBotic (MASBot) collective, in which particle-level control of chirality, activity, and pairwise interactions enables access to distinct phases of odd matter. By continuously increasing repulsive forces relative to attractive and transverse forces, we experimentally map a transition from an odd elastic crystal to an odd viscous liquid, and then to a chiral active gas. We find that this latter phase forms a non-space-filling, nonreciprocal active gas stabilized by long-range hydrodynamic attractive forces, whose statistical signatures are consistent with those of a two-dimensional self-gravitating point vortex gas. Within these phases, adjusting spinning frequency and introducing spatially patterned activity allows us to fine-tune odd mechanical responses and tailor power spectra. Further polar and rotational symmetry breaking at the particle scale leads to novel emergent states such as phase separation and collective translation. Together, our system provides a fundamental experimental testbed for nonequilibrium physics and establishes a blueprint for treating robotic swarms as programmable states of matter, enabling functions that range from resilient structures to adaptive swarm reconfiguration.

cond-mat.soft↗

arXiv2024

Grasping and Rolling In-plane Manipulation Using Deployable Tape spring Appendages

Rigid multi-link robotic arms face a tradeoff between their overall reach distance (the workspace), and how compactly they can be collapsed (the storage volume). Increasing the workspace of a robot arm requires longer links, which adds weight to the system and requires a larger storage volume. However, the tradeoff between workspace and storage volume can be resolved by the use of deployable structures with high extensibility. In this work we introduce a bidirectional tape spring based structure that can be stored in a compact state and then extended to perform manipulation tasks, allowing for a large manipulation workspace and low storage volume. Bidirectional tape springs are demonstrated to have large buckling strength compared to single tape springs, while maintaining the ability to roll into a compact storage volume. Two tape spring structures are integrated into a bimanual manipulator robot called GRIP-tape that allows for object Grasping and Rolling In Planar configurations (GRIP). In demonstrations we show that the continuum kinematics of the tape springs enable novel manipulation capabilities such as simultaneous translation-rotation and multi-object conveyance. Furthermore, the dual mechanical properties of stiffness and softness in the tape springs enables inherent safety from unintended collisions within the workspace and soft-contact with objects. Our system demonstrates new opportunities for extensible manipulators that may benefit manipulation in remote environments such as space and the deep sea.

cs.RO↗