Structural design and output characteristic analysis of magnetostrictive tactile sensor for robotic applications

Wendong Zheng,Ling Weng,Yunkai Li,Ran Zhao,Bowen Wang,Huaping Liu,Changgeng Zhang

doi:10.1063/1.5006448

Abstract

A novel magnetostrictive tactile sensor has been designed according to the transduction mechanism of cilia and Villari effect of iron-gallium alloy. The tactile sensor consists of a Galfenol beam, a pair of permanent magnets, a Hall sensor and a signal processing system. Compared with the conventional tactile sensor, our proposed tactile sensor can not only detect the contact-force, but also sense stiffness of an object. The performance and measurement range of tactile sensor have theoretically been analyzed and experimentally investigated. The results have revealed that the sensibility of tactile sensor for sensing force is up to 22.81mV/N at applied bias magnetic field of 2.56kA/m. Moreover, the sensor can effectively discriminate objects with different stiffness. The sensor is characterized by high sensitivity, good linearity, and quick response. It has the potential of being miniaturized and integrated into the finger of a robotic hand to realize force sensing and object recognition in real-time.

Highlights

The development of tactile sensors has attracted a lot of research interest over the last decades, in particular in the areas of transduction methods, materials, and tactile sensation of robots
In this work, enlightened by the transduction mechanism of cilia and Villari effect of Galfenol, we proposed a magnetostrictive tactile sensor with the functions of contact force and elasticity sensing
The output characteristic model of the sensor is established based on the dynamic theory of Euler-Bernoulli beam, the Jiles-Atherton model, the Hertz contact theory

Summary

Introduction

The development of tactile sensors has attracted a lot of research interest over the last decades, in particular in the areas of transduction methods, materials, and tactile sensation of robots. Various types of tactile sensors have been presented using transduction mechanism of piezoelectricity, piezoresistivity, and capacitivity for a robot.[1,2] little research on tactile sensing of magnetostriction effect has been reported in literatures. The iron-gallium alloy (Galfenol) is a kind of magnetostrictive material, which combines significant magneto-elastic effect with unique mechanical properties.[3] The inverse-magnetostriction effect indicates that the elastic deformation changes magnetic domain orientation, directly altering the net magnetization of the material that can be used for sensor applications.[4] Downey et al have investigated the magnetoelastic bending behavior of Galfenol and demonstrated that it can be used in a variety of novel sensors.[5] the superior properties of Galfenol with respect to rare earth materials, such as low field magnetostriction,[6] high mechanical strength, and good ductility, make it have a great potential as an active structural material for tactile sensing

Methods

Results

Conclusion