Flexible Temperature Sensor Integrated with Soft Pneumatic Microactuators for Functional Microfingers

Satoshi Konishi,Akiya Hirata

doi:10.1038/s41598-019-52022-x

Abstract

The integration of a flexible temperature sensor with a soft microactuator (a pneumatic balloon actuator) for a functional microfinger is presented herein. A sensor integrated with a microactuator can actively approach a target for contact detection when a distance exists from the target or when the target moves. This paper presents a microfinger with temperature sensing functionality. Moreover, thermocouples, which detect temperature based on the Seebeck effect, are designed for use as flexible temperature sensors. Thermocouples are formed by a pair of dissimilar metals or alloys, such as copper and constantan. Thin-film metals or alloys are patterned and integrated in the microfinger. Two typical thermocouples (K-type and T-type) are designed in this study. A 2.0 mm × 2.0 mm sensing area is designed on the microfinger (3.0 mm × 12 mm × 400 μm). Characterization indicates that the output voltage of the sensor is proportional to temperature, as designed. It is important to guarantee the performance of the sensor against actuation effects. Therefore, in addition to the fundamental characterization of the temperature sensors, the effect of bending deformation on the characteristics of the temperature sensors is examined with a repeated bending test consisting of 1000 cycles.

Highlights

Various teleoperated manipulators have been developed in robotics for operation in inaccessible environments[1]
A flexible temperature sensor was designed to be integrated into a soft microfinger that was fabricated using PDMS and driven by a pneumatic balloon actuators (PBAs)
The soft microfinger was designed as a disposable device for safety considerations in biomedical applications

Summary

Introduction

Various teleoperated manipulators have been developed in robotics for operation in inaccessible environments[1]. A fluid-resistive strain sensor with a microchannel was integrated with a PBA via batch fabrication to detect the bending motion of a microfinger. The function of tactile sensing using this type of strain sensor has been studied by analyzing the influence of the force from a contacted object on the bending motion of a microfinger. Electrical resistance changes depending on the strain It is important for thermocouples composed of thin-film metals or alloys to perform reliability against such actuation effects. Polymer-based organic photonic devices have been demonstrated by combining highly flexible conducting polymers, semiconducting polymers and thin metal layers[28,30] These smart designs would be effective in improving the robustness of sensors integrated into microfingers in the future, regardless of the sufficient reliability demonstrated by the current device in our application

Objectives

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Conclusion