ArrayTac: A Closed-loop Piezoelectric Tactile Platform for Continuously Tunable Rendering of Shape, Stiffness, and Friction

TL;DR

ArrayTac is a novel closed-loop piezoelectric tactile display capable of rendering shape, stiffness, and friction simultaneously with high fidelity, enabling advanced remote and multidimensional haptic interactions.

Contribution

The paper introduces ArrayTac, a high-fidelity, continuously tunable tactile platform that integrates three-dimensional cues for realistic touch simulation.

Findings

Participants accurately identified 3D shapes and material properties through touch.

ArrayTac successfully rendered images and detected tumors remotely with high accuracy.

The platform demonstrated high refresh rate and bandwidth for realistic tactile feedback.

Abstract

Human touch depends on the integration of shape, stiffness, and friction, yet existing tactile displays cannot render these cues together as continuously tunable, high-fidelity signals for intuitive perception. We present ArrayTac, a closed-loop piezoelectric tactile display that simultaneously renders these three dimensions with continuous tunability on a 4 by 4 actuator array. Each unit integrates a three-stage micro-lever amplifier with end-effector Hall-effect feedback, enabling up to 5 mm displacement, greater than 500 Hz array refresh, and 123 Hz closed-loop bandwidth. In psychophysical experiments, naive participants identified three-dimensional shapes and distinguished multiple stiffness and friction levels through touch alone without training. We further demonstrate image-to-touch rendering from an RGB image and remote palpation of a medical-grade breast tumor phantom over 1,000 km, in which all 11 naive participants correctly identified tumor number and type with sub-centimeter localization error. These results establish ArrayTac as a platform for multidimensional haptic rendering and interaction.