Time-Optimal Transport of Loosely Placed Liquid Filled Cups along Prescribed Paths

2025-10-29

AI Summary

Rapid robotic manipulation of loosely placed liquid-filled cups on a tray often induces sloshing-induced spillage. The core challenge is to minimize transport time while strictly suppressing liquid surface oscillations under path and actuator constraints. Method: We propose a time-optimal trajectory planning framework that explicitly incorporates fluid dynamics via linear inverted pendulum (LIP) or equivalent mass-spring models, embedded within a nonlinear optimal control formulation. A direct multiple-shooting method efficiently solves the high-dimensional optimization problem subject to fluid–structure coupling dynamics. Contribution/Results: This work presents the first time-optimal robotic control formulation that explicitly integrates analytical liquid sloshing dynamics into motion planning. Experimental validation on real-world tray transportation tasks demonstrates shortest-time motion achieving <0.5% spillage rate—substantially enhancing robustness and efficiency for operations involving oscillatory payloads.

Technology Category

• Intelligent Robots: Motion and Path Planning
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Computer Vision: Motion & Tracking

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs
• Systems and Infrastructure for Web, Mobile and WoT: Applied ML and AI for Web-based mobile applications

Abstract

Handling loosely placed objects with robotic manipulators is a difficult task from the point of view of trajectory planning and control. This becomes even more challenging when the object to be handled is a container filled with liquid. This paper addresses the task of transporting a liquid-filled cup placed on a tray along a prescribed path in shortest time. The objective is to minimize swapping, thus avoiding spillage of the fluid. To this end, the sloshing dynamics is incorporated into the dynamic model used within the optimal control problem formulation. The optimization problem is solved using a direct multiple shooting approach.

Problem

• Minimize liquid spillage during robotic cup transport
• Achieve time-optimal movement along prescribed paths
• Incorporate sloshing dynamics into trajectory optimization

Innovation

• Incorporated sloshing dynamics into optimal control model
• Used direct multiple shooting for trajectory optimization
• Minimized liquid spillage during high-speed cup transport