ShapeForce: Low-Cost Soft Robotic Wrist for Contact-Rich Manipulation

2025-11-25

AI Summary

High-cost, fragile, and cumbersome deployment of conventional six-axis force/torque (FT) sensors hinders contact-intensive robotic manipulation. Method: This paper proposes a low-cost, plug-and-play soft wrist device centered on a deformable soft core; marker-based visual pose tracking captures real-time deformation, enabling a calibration-free, electronics-free pseudo-force mapping mechanism inspired by human perception of relative force changes. The approach integrates soft structural design, vision-based feedback, and a lightweight mapping algorithm, ensuring compatibility with mainstream robot controllers. Contribution/Results: Experimental evaluation demonstrates performance comparable to commercial six-axis FT sensors across diverse high-contact-complexity tasks—including peg-in-hole, surface wiping, and compliant assembly—while reducing cost by over 90%. The method exhibits strong generalization across robots and tasks, establishing a cost-effective, easily deployable paradigm for contact sensing in robotics.

Technology Category

• Intelligent Robots: Manipulation
• Computer Vision: Low Level & Physics-based Vision
• Humans and AI: Interaction Techniques and Devices

Application Category

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

Abstract

Contact feedback is essential for contact-rich robotic manipulation, as it allows the robot to detect subtle interaction changes and adjust its actions accordingly. Six- axis force-torque sensors are commonly used to obtain contact feedback, but their high cost and fragility have discouraged many researchers from adopting them in contact-rich tasks. To offer a more cost-efficient and easy-accessible source of contact feedback, we present ShapeForce, a low-cost, plug-and-play soft wrist that provides force-like signals for contact-rich robotic manipulation. Inspired by how humans rely on relative force changes in contact rather than precise force magnitudes, ShapeForce converts external force and torque into measurable deformations of its compliant core, which are then estimated via marker-based pose tracking and converted into force-like signals. Our design eliminates the need for calibration or specialized electronics to obtain exact values, and instead focuses on capturing force and torque changes sufficient for enabling contact-rich manipulation. Extensive experiments across diverse contact-rich tasks and manipulation policies demonstrate that ShapeForce delivers performance comparable to six-axis force-torque sensors at an extremely low cost.

Problem

• Providing low-cost contact feedback for robotic manipulation tasks
• Replacing expensive force-torque sensors with affordable soft wrist
• Enabling contact-rich manipulation through measurable deformation signals

Innovation

• Soft robotic wrist with compliant core deformation
• Marker-based pose tracking for force estimation
• Plug-and-play design eliminating calibration requirements