Estimating Force Interactions of Deformable Linear Objects from their Shapes

2026-02-01

AI Summary

This work addresses the challenge of accurately estimating external forces applied at non-end-effector locations on deformable linear objects—such as wires—during robotic manipulation, a key limitation for safe physical interaction. The authors propose a novel method that relies solely on depth-camera–derived shape observations, eliminating the need for additional force sensors or assumptions about end-effector contact. Under static equilibrium conditions, the approach formulates a linear system based on force–moment consistency to analytically estimate both the location and magnitude of external forces. To the best of the authors’ knowledge, this is the first technique capable of directly inferring arbitrary external forces from purely visual shape data, making it suitable for scenarios involving indirect manipulation or passive obstacles. Extensive simulations and real-world experiments demonstrate the method’s high accuracy and robustness in localizing and quantifying external forces.

Technology Category

• Intelligent Robots: Manipulation
• Computer Vision: Low Level & Physics-based Vision
• Planning, Routing, and Scheduling: Activity and Plan Recognition

Application Category

• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs
• Responsible Web: Human-perceived consequences of algorithmic deployment on the web
• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments

Abstract

This work introduces an analytical approach for detecting and estimating external forces acting on deformable linear objects (DLOs) using only their observed shapes. In many robot-wire interaction tasks, contact occurs not at the end-effector but at other points along the robot's body. Such scenarios arise when robots manipulate wires indirectly (e.g., by nudging) or when wires act as passive obstacles in the environment. Accurately identifying these interactions is crucial for safe and efficient trajectory planning, helping to prevent wire damage, avoid restricted robot motions, and mitigate potential hazards. Existing approaches often rely on expensive external force-torque sensor or that contacts occur at the end-effector for accurate force estimation. Using wire shape information acquired from a depth camera and under the assumption that the wire is in or near its static equilibrium, our method estimates both the location and magnitude of external forces without additional prior knowledge. This is achieved by exploiting derived consistency conditions and solving a system of linear equations based on force-torque balance along the wire. The approach was validated through simulation, where it achieved high accuracy, and through real-world experiments, where accurate estimation was demonstrated in selected interaction scenarios.

Problem

• deformable linear objects
• force estimation
• robot-wire interaction
• contact detection
• external force

Innovation

• deformable linear objects
• force estimation
• shape-based sensing
• static equilibrium
• force-torque balance