Emergency Stopping for Liquid-manipulating Robots

2026-04-17

AI Summary

This work addresses the challenge of liquid spillage during emergency braking in robotic liquid handling by proposing, for the first time, an emergency stop mechanism that integrates nonlinear liquid dynamics with real-time responsiveness. The approach formulates the braking process as a time-optimal control problem and leverages model predictive control to generate spill-free stopping trajectories. These trajectories are implemented as a plug-and-play safety layer within existing anti-sloshing motion planning frameworks. By combining optimal control theory with a high-fidelity liquid dynamics model, the method achieves rapid deceleration while rigorously preventing spillage. Experimental validation in both simulation and on a Franka Emika Panda seven-degree-of-freedom robotic platform demonstrates the efficacy of the proposed strategy, confirming its ability to execute fast emergency stops without liquid overflow.

Technology Category

• Intelligent Robots: Motion and Path Planning
• Planning, Routing, and Scheduling: Replanning and Plan Repair
• Natural Language Processing: Safety and Robustness

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Search and Retrieval-Augmented AI: Web learning to rank, online learning, and counterfactual learning for ranking
• Systems and Infrastructure for Web, Mobile and WoT: Applied ML and AI for Web-based mobile applications

Abstract

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.

Problem

• emergency stopping
• liquid manipulation
• spill-free
• robotics
• hazard response

Innovation

• emergency stopping
• liquid manipulation
• model predictive control
• optimal control
• slosh dynamics