HapMorph: A Pneumatic Framework for Multi-Dimensional Haptic Property Rendering

2025-09-05

AI Summary

Existing wearable haptic interfaces struggle to simultaneously and independently modulate multiple physical attributes—such as object size and stiffness—in a continuous, decoupled manner. To address this, we propose a lightweight, wearable haptic interface based on antagonistic fabric pneumatic actuators. Our approach enables the first continuous, decoupled control of size and stiffness, along with morphologically adaptive expansion. Leveraging coordinated dual-chamber pneumatic actuation, a custom-designed flexible fabric-based pneumatic structure, and closed-loop pressure feedback, the prototype—weighing only 21 g—achieves a size range of 50–104 mm and stiffness modulation up to 4.7 N/mm. User perception experiments demonstrate that users can reliably distinguish nine distinct size–stiffness states across three categories with 89.4% accuracy. This work significantly advances the precision and practicality of multidimensional haptic rendering in wearable systems.

Technology Category

• Humans and AI: Interaction Techniques and Devices
• Intelligent Robots: Manipulation
• Cognitive Modeling & Cognitive Systems: Simulating Human Behavior

Application Category

• User Modeling, Personalization and Recommendation: On-Device user modeling, personalization, and recommendation
• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Systems and Infrastructure for Web, Mobile and WoT: Web performance, measurement, and characterization

Abstract

Haptic interfaces that can simultaneously modulate multiple physical properties remain a fundamental challenge in human-robot interaction. Existing systems typically allow the rendering of either geometric features or mechanical properties, but rarely both, within wearable form factors. Here, we introduce HapMorph, a pneumatic framework that enables continuous, simultaneous modulation of object size and stiffness through antagonistic fabric-based pneumatic actuators (AFPAs). We implemented a HapMorph protoytpe designed for hands interaction achieving size variation from 50 to 104 mm, stiffness modulation up to 4.7 N/mm and mass of the wearable parts of just 21 g. Through systematic characterization, we demonstrate decoupled control of size and stiffness properties via dual-chamber pressure regulation. Human perception studies with 10 participants reveal that users can distinguish nine discrete states across three size categories and three stiffness levels with 89.4% accuracy and 6.7 s average response time. We further demonstrate extended architectures that combine AFPAs with complementary pneumatic structures to enable shape or geometry morphing with concurrent stiffness control. Our results establish antagonistic pneumatic principle as a pathway toward next-generation haptic interfaces, capable of multi-dimensiona rendering properties within practical wearable constraints.

Problem

• Simultaneously modulating multiple haptic properties in wearable interfaces
• Enabling continuous control of both object size and stiffness
• Achieving multi-dimensional haptic rendering within practical wearable constraints

Innovation

• Pneumatic framework for simultaneous size and stiffness modulation
• Antagonistic fabric-based pneumatic actuators enable decoupled control
• Combines AFPAs with complementary structures for shape morphing