IROS 2022 - Slosh-free Robot Trajectory Optimization

“Jenkins! You have too much coffee in your mug!”
The general expression to say there is nothing worse than spilling coffee/hot beverages on oneself or others is the starting point of the no-spilling robotics solution that I have developed with Mr Laha and Mr Muchacho at MIRMI - TUM. The work is focused on the Geriatronics project and the elderly care scenario whereby it is critical for a robot to serve food / liquids, such as hot soups and/or beverages, to an elderly while being reactive and guaranteeing not spilling. The solution takes inspiration from the past and models the robot motion as the 300-year-old Maroccan tea tray devise ensuring above-human motions with large velocities without spilling even when the cup is filled up to the water surface tension. The solution is not only for coffee or hot beverages, but can be extended to industrial applications or any scenario that requires fast and above-human liquid or non-prehensile transportation.

This video is related to our work accepted at IROS-22.

The work is entitled: "Slosh-free Robot Trajectory Optimization"
Authors: Rafael I. Cabral Muchacho, Riddhiman Laha, Luis Figueredo, Sami Haddadin.

Abstract:
In this work, we propose a motion planning strategy for high-speed spill-free fluid transportation using robot manipulators. The conditions for a slosh-free motion are carefully studied and a solution based on modeling the motion dynamics as a spherical pendulum is proposed to minimize the main source of sploshing, i.e., lateral reaction forces of the container. In contrast to existing solutions which are either highly-computationally complex or focused on minimizing jerks and accelerations alone, the proposed approach can be deployed online by linearizing the dynamics around equilibrium and casting the optimization problem as a quadratic program. We notice that even for aggressive trajectories, the small angle approximation is rarely violated. The effectiveness of the proposed approach has been validated by thorough simulation studies as well as several experimental results as shown in this video.