Learning Equivariant Neural-Augmented Object Dynamics From Few Interactions
This work addresses the challenge of data-efficient dynamics modeling for robotic manipulation of deformable objects, which is critical for real-world robot learning.
PIEGraph combines a physically informed spring-mass system with an equivariant graph neural network to model object dynamics from few interactions, achieving accurate long-horizon predictions and outperforming state-of-the-art baselines on reorientation and repositioning tasks with ropes, cloth, stuffed animals, and rigid objects.
Learning data-efficient object dynamics models for robotic manipulation remains challenging, especially for deformable objects. A popular approach is to model objects as sets of 3D particles and learn their motion using graph neural networks. In practice, this is not enough to maintain physical feasibility over long horizons and may require large amounts of interaction data to learn. We introduce PIEGraph, a novel approach to combining analytical physics and data-driven models to capture object dynamics for both rigid and deformable bodies using limited real-world interaction data. PIEGraph consists of two components: (1) a \textbf{P}hysically \textbf{I}nformed particle-based analytical model (implemented as a spring--mass system) to enforce physically feasible motion, and (2) an \textbf{E}quivariant \textbf{Graph} Neural Network with a novel action representation that exploits symmetries in particle interactions to guide the analytical model. We evaluate PIEGraph in simulation and on robot hardware for reorientation and repositioning tasks with ropes, cloth, stuffed animals and rigid objects. We show that our method enables accurate dynamics prediction and reliable downstream robotic manipulation planning, which outperforms state of the art baselines.