Large language models (LLMs) can provide rich physical descriptions of most worldly
objects, allowing robots to achieve more informed and capable grasping.
We leverage LLMs' common sense physical reasoning and code-writing abilities to
infer an object's physical characteristics—mass m, friction coefficient µ, and
spring constant k—from a semantic description, and then translate those
characteristics into an executable adaptive grasp policy. Using a
current-controllable, two-finger gripper with a built-in depth camera, we
demonstrate that LLM-generated, physically-grounded grasp policies outperform
traditional grasp policies on a custom benchmark of 12 delicate and deformable items
including food, produce, toys, and other everyday items, spanning two orders of
magnitude in mass and required pick-up force. We also demonstrate how compliance
feedback from DeliGrasp policies can aid in downstream tasks such as measuring
produce ripeness.