Analysis and Design of a Cantilever as a Vertical Graphene-Based Displacement Sensor

Displacement measurement is crucial across various fields, and this study introduced an innovative system using vertical graphene (VG) for this purpose. The system incorporates cantilevers and wedge structures to minimize graphene material deformation. The study delves into the sensing mechanism of flexible VG sensors, involving sliding, crack propagation, carbon nanofragment contact changes, and tunneling effects in graphene sheets. Additionally, the impact of temperature annealing and aging treatment on VG sensor stability was explored, along with an assessment of VG bars’ temperature sensitivity. The results show that the VG sensor’s relative resistance change rate increases with temperature up to 70 °C, with decreased stability beyond that point. Calibration tests demonstrated the sensor’s performance, revealing a measurement range of 0–30 mm, a sensitivity of 20%, and a resolution of 0.0094 mm. The hysteresis error was measured at 0.33%, with repeatability and accuracy errors at 10.39% and 7.47%, respectively. These outcomes underscore the sensor’s potential for diverse sensing applications.

I. Introduction

Displacement measurement plays a crucial role in various fields such as civil engineering [1], aerospace [2], and mechanical engineering [3]. Nevertheless, existing displacement measurement technologies face certain limitations. For example, surface tool displacement sensor technology demands high-precision self-compensation functions, resulting in elevated labor costs [4]. While the linear variable differential transformer (LVDT) has good environmental adaptability, its installation is complex [5], and the measurement accuracy can be reduced if the installation direction is not precisely aligned with the displacement direction. To address these limitations, Gao et al. [6] developed a 2-D displacement measurement system based on grating, which realized multidimensional measurement technology. Additionally, hostile work environments, subpar performance, and exorbitant costs render several current measurement methods impractical. Some researchers have introduced capacitive sensor systems with varying performance indicators that meet the specific requirements of these tasks admirably. Capacitive sensors, being compact, uncomplicated, and possessing high detection capabilities, prove to be well-suited. Nevertheless, this system encounters challenges associated with manufacturing high-precision, large-area gratings and the necessity for miniaturization. As the intelligent high-end manufacturing industry is driven by new materials, measurement methods, and network communication technologies [7], [8], there is a need for research and attention to improve device performance requirements, which helped to overcome the limitations of traditional testing methods and advance the field of displacement measurement.