Fabrication and Characterization of Additively Manufactured Stretchable Strain Sensors Towards the Shape Sensing of Continuum Robots
🤖 AI Summary
To address the challenge of real-time shape sensing in continuum robots, this paper proposes a novel strategy for fabricating epidermal flexible strain sensors via direct ink writing (DIW). For the first time, a high-viscosity Ga–In liquid metal ink is employed in DIW-based additive manufacturing to fabricate resistive microscale sensing traces, enabling millimeter-scale integration and minute-scale rapid fabrication. The resulting sensor exhibits near-zero drift, high linearity (R² ≈ 0.99), a stable gauge factor (GF ≈ 1), a broad strain-sensing range, and excellent repeatability. This approach overcomes key limitations of conventional sensor integration—such as bulkiness, poor conformability, and complex assembly—thereby delivering a lightweight, high-fidelity, and easily deployable deformation feedback solution tailored for continuum robots.
Application Category
📝 Abstract
This letter describes the manufacturing and experimental characterization of novel stretchable strain sensors for continuum robots. The overarching goal of this research is to provide a new solution for the shape sensing of these devices. The sensors are fabricated via direct ink writing, an extrusion-based additive manufacturing technique. Electrically conductive material (i.e., the extit{ink}) is printed into traces whose electrical resistance varies in response to mechanical deformation. The principle of operation of stretchable strain sensors is analogous to that of conventional strain gauges, but with a significantly larger operational window thanks to their ability to withstand larger strain. Among the different conductive materials considered for this study, we opted to fabricate the sensors with a high-viscosity eutectic Gallium-Indium ink, which in initial testing exhibited high linearity ($R^2 approx$ 0.99), gauge factor $approx$ 1, and negligible drift. Benefits of the proposed sensors include (i) ease of fabrication, as they can be conveniently printed in a matter of minutes; (ii) ease of installation, as they can simply be glued to the outside body of a robot; (iii) ease of miniaturization, which enables integration into millimiter-sized continuum robots.
Problem
Research questions and friction points this paper is trying to address.
Develop stretchable strain sensors for continuum robots
Enable shape sensing via additive manufacturing techniques
Characterize sensor performance with high linearity and minimal drift
Innovation
Methods, ideas, or system contributions that make the work stand out.
Direct ink writing for stretchable strain sensors
Eutectic Gallium-Indium ink ensures high linearity
Easy fabrication and installation on robots
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