Feel the Tension: Manipulation of Deformable Linear Objects in Environments with Fixtures using Force Information

Abstract

Humans are able to manipulate Deformable Linear Objects (DLOs) such as cables and wires, with little or no visual information, relying mostly on force sensing. In this work, we propose a reduced DLO model which enables such blind manipulation by keeping the object under tension. Further, an online model estimation procedure is also proposed. A set of elementary sliding and clipping manipulation primitives are defined based on our model. The combination of these primitives allows for more complex motions such as winding of a DLO. The model estimation and manipulation primitives are tested individually but also together in a real-world cable harness production task, using a dual-arm YuMi, thus demonstrating that force-based perception can be sufficient even for such a complex scenario.

Improved results on state estimation for switched continuous‐time linear systems

“…These shape control tasks pose a significant challenge due to the inherent mismatch between the finite constraints that can be imposed on DLOs by manipulators and the infinite degrees of freedom DLOs possess [4]. In tackling this challenge and striving to achieve complex shapes, additional constraints are required, typically provided by contacts from environmental fixtures [1], [5]- [9]. To safely fasten DLOs using fixtures, reliable contact state estimation is crucial for prevention of potential anomalies such as misalignment or insufficient pushing, and for enhancing the overall robustness of the shape control system.…”

“…RELATED WORK The utilization of environmental fixtures to control the shape of DLOs was first introduced by Zhu et al [5]. Since then, there has been a widespread adoption of this approach in DLO manipulation [1], [4], [6]- [9]. A crucial step in this process is estimating the contact status of the DLO constrained by fixtures.…”

“…Finally, DLO manipulation primarily involves contact with only a small segment of the DLO, which makes focusing on the existence and position of contact points more suitable than creating a contact distribution. Therefore, previous works in manipulation of DLOs tend to adopt more intuitive and computationally efficient criteria to estimate the contact states, either by detecting the contact establishment and resulting shape changes from top images [4]- [8], or by detecting the contact position on the DLO from force measurements [1], [9].…”