Manipulating open liquid containers is challenging because liquids are highly sensitive to vessel accelerations and jerks. Although spill-free liquid manipulation has been widely studied, emergency stopping under unexpected hazards has received little attention, despite the fact that abrupt braking may cause hazardous spills. This letter presents an emergency stop system for robots manipulating liquids in open containers. We formulate emergency stopping as an optimal control problem and solve it in a model predictive control framework to generate time-optimal, spill-free stopping trajectories. The method operates as a plug-and-play safety layer on top of existing slosh-free motion planning methods, enabling immediate reaction to detected hazards while accounting for nonlinear liquid dynamics. We demonstrate, through simulation and on a 7-DoF Franka Emika Panda robot, that the proposed approach achieves fast emergency stopping without spilling.
Samuli Hynninen, Mohammad Amman, Meri Mäkelä, Anirvan Dutta, Ville Kyrki
原文摘要
Granular materials exhibit complex and highly variable interaction dynamics, making their reliable manipulation challenging without knowledge of their physical properties. We present an interactive perception framework that infers granular material properties directly from force-torque measurements acquired during scooping. The proposed Latent Filter++ combines a bio-inspired frequency-temporal filter-bank representation with a causal latent dynamical model, allowing the representation to evolve as interaction observations become available while avoiding hand-crafted signal preprocessing. The learned latent representation captures physically meaningful variation in granular materials and supports estimation of properties including grain size and bulk density. Evaluated on 26 diverse granular materials, the approach generalizes to materials excluded from training and enables few-shot adaptation of property-specific mappings using a small number of additional interaction samples. Finally, we demonstrate the relevance of the inferred properties to downstream manipulation by examining their correlation with the maximum acceleration the materials can withstand without spilling from the spoon during transport.