Stretchable and High-Precision Optical Tactile Sensor for Trajectory Tracking of Parallel Mechanisms

2025-12-23

AI Summary

Addressing the challenge of simultaneously achieving high spatial resolution, axial self-decoupling, and off-axis interference suppression in stretchable tactile sensors, this work introduces a novel optical flexible tactile sensing mechanism based on continuous spectral filtering. The approach integrates optical encoding, elastomeric waveguide microstructures, spectral-domain continuous demodulation algorithms, and soft–hard co-packaging fabrication. It achieves 7 μm spatial resolution and 5 mN force resolution, maintains high linearity (R² = 0.996) under stretching and bending, and exhibits robustness against puncture and cutting, alongside structural scalability. When integrated onto a planar parallel manipulator, the sensor enables real-time trajectory tracking with 0.02° rotational resolution, demonstrating high-fidelity dynamic tactile feedback. This study pioneers the application of continuous spectral filtering to stretchable optical tactile sensing, establishing a new paradigm for perception in soft robotics.

Technology Category

• Intelligent Robots: Multimodal Perception & Sensor Fusion
• Search and Optimization: Mixed Discrete/Continuous Search
• Constraint Satisfaction and Optimization: Mixed Discrete/Continuous Optimization

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments
• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Search and Retrieval-Augmented AI: Personalized, context-aware and across-device search

Abstract

Stretchable sensors indicate promising prospects for soft robotics, medical devices, and human-machine interactions due to the high compliance of soft materials. Discrete sensing strategies, including sensor arrays and distributed sensors, are broadly involved in tactile sensors across versatile applications. However, it remains a challenge to achieve high spatial resolution with self-decoupled capacity and insensitivity to other off-axis stimuli for stretchable tactile sensors. Herein, we develop a stretchable tactile sensor based on the proposed continuous spectral-filtering principle, allowing superhigh resolution for applied stimuli. This proposed sensor enables a high-linear spatial response (0.996) even during stretching and bending, and high continuous spatial (7 μm) and force (5 mN) resolutions with design scalability and interaction robustness to survive piercing and cutting. We further demonstrate the sensors' performance by integrating them into a planar parallel mechanism for precise trajectory tracking (rotational resolution: 0.02°) in real time.

Problem

• Develops a stretchable optical tactile sensor for high-precision sensing
• Achieves high spatial and force resolution with self-decoupled capacity
• Enables real-time trajectory tracking in parallel mechanisms despite stretching

Innovation

• Continuous spectral-filtering principle for superhigh resolution
• High-linear spatial response during stretching and bending
• Integrated into parallel mechanism for precise trajectory tracking