A Polyetheretherketone Six-Axis Force/Torque Sensor

Liyue Fu,Aiguo Song,Dapeng Chen

doi:10.1109/access.2019.2932387

Abstract

At present, six-axis force/torque (F/T) sensor has been increasingly used in robot application, and most of the elastic elements of resistance strain type F/T sensors are made of metal materials, such as alloy steel, stainless steel, aluminum alloy, and so on. In this paper, a novel six-axis F/T sensor based on Polyetheretherketone (PEEK) material is presented. Comparison with ordinary F/T sensor purpose was served by building simplified statics model that demonstrates the conclusion of highly sensitivity of the F/T sensor based on PEEK material. The strain mapped on the strain sensitive path was analyzed using finite element analysis (FEA), frequency response curves were depicted by means of harmonic analysis, and the static and dynamic performances analyses of the six-axis F/T sensor based on PEEK material (later called PEEK sensor) were studied. Moreover, the properties of this sensor were compared with a six-axis F/T sensor based on aluminum alloy 2024 material (later called metallic sensor). The results show the properties of linearity (≤1%), hysteresis (≤2%), high sensitivity (force: ≥ 2.37×10 -4 /N; torque (Tx, Ty): 0.19×10 -4 /Nmm), and crosstalk (≤8%) between the dominant F/T component and other components. The dynamic response time of the PEEK sensor was also measured via dynamic calibration experiment, which is much higher than that of the metallic sensor. This study demonstrates that the PEEK sensor has a comparable static performance with the metallic sensor, and even higher sensitivity, but it is only suitable for measurement below 200 Hz.

Highlights

Force sensing systems have emerged in a variety of industrial automation equipment since the late 1970s [1]–[5]
In order to show the performances of the six-axis F/T sensor made of PEEK material better, two F/T sensors prototypes with identical structures and sizes, but different materials (i.e. PEEK and Aluminum alloy 2024) of the cross-beam elastic element are made
Various performance indices of the PEEK sensor are obtained via finite element analysis (FEA) and calibration experiments, and compared with the metallic sensor

Summary

INTRODUCTION

Force sensing systems have emerged in a variety of industrial automation equipment since the late 1970s [1]–[5]. We select PEEK material as a substitute for aluminum alloy 2024 to make cross-beam elastic element. In order to show the performances of the six-axis F/T sensor made of PEEK material better, two F/T sensors prototypes with identical structures and sizes, but different materials (i.e. PEEK and Aluminum alloy 2024) of the cross-beam elastic element are made. The cross beams have bending deformation when forces/ torques in different directions are applied on the central position of the elastic element. The strains of the principal beams of two materials (i.e. aluminum alloy and PEEK) can be derived as follows. The sensitivity of the elastic beam based on PEEK material is 26 times of the beam based on aluminum alloy material

FINITE ELEMENT ANALYSIS

STATIC PERFORMANCES ANALYSIS AND DISCUSSION

DYNAMIC PERFORMANCES ANALYSIS AND COMPARISON

Findings

CONCLUSIONS