Design, Modelling and Characterisation of a Miniature Fibre-Reinforced Soft Bending Actuator for Endoluminal Interventions

2026-03-25

AI Summary

This work proposes a centimeter-scale, single-chamber soft bending actuator reinforced with fiber architecture to meet the stringent demands of natural orifice interventional procedures—namely, large bending capability, hermetic sealing, and structural robustness. The design integrates multi-hardness silicone segments via casting, embedded Kevlar helical reinforcement, and a high-fidelity Abaqus finite element model incorporating hyperelastic material calibration and embedded beam enhancement for synergistic optimization of compactness and performance. Experimental results demonstrate that the optimized 100 SH configuration achieves a bending angle of 202.9° under 100 kPa driving pressure, with simulation predicting a peak deflection of 297.6°, while effectively suppressing radial expansion to satisfy the spatial constraints of medical device integration. This approach offers a promising solution for minimally invasive interventions within highly confined anatomical pathways.

Technology Category

• Search and Optimization: Sampling/Simulation-based Search
• Intelligent Robots: Manipulation
• Machine Learning: Hardware-aware ML

Application Category

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

Abstract

Miniaturised soft pneumatic actuators are crucial for robotic intervention within highly constrained anatomical pathways. This work presents the design and validation of a fibre-reinforced soft actuator at the centimetre scale for inte- gration into an endoluminal robotic platform for natural-orifice interventional and diagnostic applications. A single-chamber geometry reinforced with embedded Kevlar fibre was de- signed to maximise curvature while preserving sealing integrity, fabricated using a multi-stage multi-stiffness silicone casting process, and validated against a high-fidelity Abaqus FEM using experimentally parametrised hyperelastic material models and embedded beam reinforcement. The semi-cylindrical actuator has an outer diameter of 18,mm and a length of 37.5,mm. Single and double helix winding configurations, fibre pitch, and fibre density were investigated. The optimal 100 SH configuration achieved a bending angle of 202.9° experimentally and 297.6° in simulation, with structural robustness maintained up to 100,kPa and radial expansion effectively constrained by the fibre reinforcement. Workspace evaluation confirmed suitability for integration into the target device envelope, demonstrating that fibre-reinforcement strategies can be effectively translated to the centimetre regime while retaining actuator performance.

Problem

• soft actuator
• endoluminal intervention
• miniaturisation
• fibre reinforcement
• bending performance

Innovation

• soft actuator
• fibre reinforcement
• miniaturisation
• endoluminal robotics
• hyperelastic modelling