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Journal of Sensors
Volume 2017 (2017), Article ID 1241280, 8 pages
Research Article

A Two-Dimensional Deflection Sensor Based on Force Sensing Resistors

State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150001, China

Correspondence should be addressed to Chunya Wu

Received 10 March 2017; Revised 17 May 2017; Accepted 22 May 2017; Published 5 July 2017

Academic Editor: Lucio Pancheri

Copyright © 2017 Chuangqiang Guo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A flexible deflection sensor for elastic shaft with the capability of measuring the amplitude and direction of bending is introduced in this paper. A thin force sensing resistors (FSR) film is taken as its basic material, which is sandwiched by an elastomer layer and a printed circuit board (PCB) with detecting electrode grids. Two fix rings are used to fix the three thin components perpendicularly to the longitudinal direction of the flexible shaft. When the shaft bends under forces, the fix rings will generate a normal pressure on FSR, which will cause the change of the resistance. Therefore, the amplitude of bending can be got based on the value of resistance. The electrode grid on the PCB is divided into four detection areas used to estimate the distribution of normal pressure on the FSR; thus the bending direction of shaft can also be obtained. Test results of a prototype (140 mm in length) show that the amplitude of deflection can reach 30 mm and the sensitivities of sensor are 40.37, 32.8, 37.77, and 39.47 mV/mm in the four directions, respectively. The proposed flexible deflection sensor can be applied in continuum robots or other applications, which require rapid measurement of bending amplitude and direction.