MoiréTac: A Dual-Mode Visuotactile Sensor for Multidimensional Perception Using Moiré Pattern Amplification

Anonymous Submission

Abstract

Visuotactile sensors typically employ sparse marker arrays that limit spatial resolution and lack clear analytical force-to-image relationships. To solve this problem, we present MoiréTac, a dual-mode sensor that generates dense interference patterns via overlapping micro-gratings within a transparent architecture. When two gratings overlap with slight misalignment, they create moiré patterns that amplify microscopic deformations. The design preserves optical clarity for vision tasks while producing continuous moiré fields for tactile sensing.

We combine physics-based features (brightness, phase gradient, orientation, and period) from moiré patterns with deep spatial features. These are mapped to six-axis force/torque measurements, enabling interpretable force/torque regression through end-to-end learning. Experimental results demonstrate three capabilities: six-axis force/torque measurement with R²>0.98 across tested axes; sensitivity tuning through geometric parameters (threefold gain adjustment); and vision functionality for object classification despite moiré overlay. Finally, we integrate the sensor into a robotic arm for cap removal with coordinated force and torque control, validating its potential for dexterous manipulation.

Video Demonstration

Key Contributions

  1. Moiré interferometry for visuotactile sensing: We apply moiré pattern amplification to transform marker-based sensing into continuous interference fields, achieving R²>0.98 across six force/torque axes. Unlike sparse marker methods that interpolate between discrete points, our continuous fields directly encode mechanical deformations at every pixel.
  2. Physics-grounded force/torque framework: We establish analytical mappings from four moiré observables (I, ∇φ, θ, Λ) to six-axis wrench, enabling sensitivity adjustment through geometric parameters. This interpretable approach permits analytical sensitivity analysis and systematic calibration transfer, capabilities absent in pure learning-based methods.
  3. Transparent dual-mode operation: We maintain optical transparency for object recognition while measuring forces, demonstrated in automated cap removal tasks. The preserved visual channel operates concurrently with tactile sensing, unlike opaque sensors that lose visual information upon contact.

Overview

Overview

Overview of MoiréTac. The dual-grating optical system generates moiré observables, which are mapped to force/torque measurements. The top-left panels show how press and rotation affect stripe density and orientation.

Structure Illustration

Structure

Structure illustration showing mapping from Moiré observables (intensity I, phase ∇φ, angle θ, wavelength Λ) to six-axis force/torque sensing with the layered architecture and cross-section view.

Sensor Fabrication

Fabrication

Fabrication process of MoiréTac sensor showing assembly steps from optical base assembly to sensing layer completion and final integration.

System Workflow

Workflow

Overview of the MoiréTac processing pipeline with dual-mode operation for vision and tactile sensing.

Six-Axis Force/Torque Calibration

Six-axis Calibration

Six-axis force/torque calibration results demonstrating high accuracy (R²>0.98) across all axes with experimental setup using robotic arm and commercial F/T reference sensor.

Dual-Mode Manipulation Demonstration

Demonstration

Hand-assisted cap removal demonstrating dual-mode operation with vision-guided approach, force feedback for grip, torque monitoring during rotation, and visual verification upon completion.

Citation

To Appear

@article{anonymous2025moiretac,
  title={MoiréTac: Comprehensive Visuotactile Perception Through Continuous Moiré Fields },
  author={Anonymous},
  journal={Anonymous Submission},
  year={2025}
}