An Improved Pendulum-Based Fiber Bragg Grating Inclinometer With the Capability of Compensating Initial Installation Deviation

This study proposes a high-performance fiber Bragg grating (FBG)-based inclinometer with the capability to self-compensate for initial installation deviation. On the one hand, the proposed inclinometer, featuring an improved pendulum design and equipped with a pair of FBGs, can accurately identify both the magnitude and direction of inclination, and it exhibits temperature-insensitive characteristics. On the other hand, with the help of a self-developed compact universal joint structure, the issue of the inclinometer’s initial tilt angle caused by installation deviation has been effectively resolved. The experimental results demonstrate that a high degree of linearity with a sensitivity of 89.464 pm/° is achieved over a wide range from −20° to 20°. The self-developed universal joint structure is compact and can effectively compensate for initial installation deviation of up to ±5° in any tilt orientation. The developed inclinometer exhibits a high degree of repeatability and long-term stability, demonstrating great potential for practical engineering applications.