Probabilistic 3D force estimation improves control of flexible cables
3D-Force Estimation for Dual-arm Manipulation of Deformable Linear Objects via Factor Graphs
Robotics
Summary
Estimating forces acting on flexible objects like cables is hard because they can bend and stretch unpredictably. The authors propose a new method that uses a type of mathematical model called factor graphs to figure out where, how strong, and in what direction forces act on such objects. Their method also reconstructs the shape of the cable at the same time. They only rely on one type of sensor data and test their approach with simulations including noise, showing accurate force estimates.
What this means in practice
- •For robotics engineers: Improve manipulation and control of flexible cables using probabilistic 3D force estimation with minimal sensor requirements.
- •For automation system designers: Design safer dual-arm robotic systems for handling deformable objects in manufacturing by accurately estimating contact forces and shapes.
Authors
Annika Delucchi, Vincenzo Di Paola, Bruno Marco Quadrelli, Matteo Zoppi
Abstract
Estimating forces acting on Deformable Linear Objects (DLOs) is challenging due to their underactuated nature. However, reliable contact estimation is crucial to precisely control them and enable safe manipulation tasks. Differently from the various approaches presented in the literature, this work adopts a probabilistic formulation where the DLO state and sensor data are related through conditional distributions. In particular, factor graphs are used to determine the magnitude, direction, and location of a 3D force acting on a DLO, while simultaneously reconstructing its shape. Since DLOs are not actuated and are typically thin, like cables and wires, strain gauges and actuation readings are usually impractical. Therefore, to overcome this issue, this work is tested using one type of sensing information only, thus developing a generic technique suited for a wider variety of tasks. Realistic tests are performed by introducing noise into the measurements while the DLO follows a prescribed path in the presence of external forces that are accurately estimated.