UVDtact: UV Marker-Embedded Fingertip-Like Vision-Based Tactile Sensor for Shape Reconstruction and Force Estimation
Woojong Kim, Won Dong Kim, Hyunkyu Park, Joonho Lee, Jeong-Jung Kim, Jung Kim
AI summary
Problem
Existing all-around vision-based tactile sensors struggle to match human fingertip size while integrating both shape reconstruction and force estimation capabilities without compromising performance or durability.
Approach
The authors developed UVDtact, a compact hemi-ellipsoid sensor that switches between white and UV illumination to decouple tactile imaging, using a two-layer UV-ink-infused translucent elastomer that darkens under contact for shape mapping and reveals embedded markers for force tracking.
Key results
- 0.172 mm shape reconstruction error
- 0.120 N force estimation error
- 60% reduction in force estimation error via UV markers
- Compact ϕ18 × 24 mm all-around sensing design
Why it matters
Enables robots to perform human-like dexterous manipulation by providing high-resolution, multi-modal tactile feedback in a compact, fingertip-sized form factor.
Abstract
Vision-based tactile sensors are highly promising for enabling robots to perform dexterous, contact-rich manip- ulation tasks by providing high-resolution tactile data. Recent studies have attempted to implement shape reconstruction and force estimation capabilities for sensors with omnidirectional sensing surfaces and a compact form factor. However, achieving a small diameter comparable to that of a human fingertip remains challenging, and integrating the multiple functionalities within the fingertip form factor poses significant challenges. In this study, we present UVDtact, a vision-based tactile sensor with a fingertip-like form factor that incorporates a switchable translucent elastomer. The proposed switchable translucent elastomer, which integrates ultraviolet (UV) ink and a translucent elastomer, decouples tactile images for shape reconstruction and force estimation. The independent tactile images ensure that shape reconstruction remains unaffected by UV markers, making them visible when needed, thereby enabling effective force estimation. For shape reconstruction, we leverage the darkening effect of the translucent elastomer in response to tactile stimuli and introduce a calibration method that utilizes this effect in an all-around curved sensor configuration. Furthermore, we validate that embedding UV markers enhances tactile features, improving force estimation performance while preserving the quality of tactile images used for shape reconstruction. By integrating various tactile sensing capabilities into a compact, fingertip-like design, UVDtact contributes to developing robotic systems with human-like dexterity.