Bio-Inspired Fiber Attitude Sensor for Direction-Distinguishable Pitching and Rolling Sensing

Attitude sensors are critical elements in the field of automation control. In this study, we propose and demonstrate a whisker-inspired fiber attitude sensor (WI-FAS) capable of simultaneously measuring pitching and rolling angles. A photopolymerized whisker grows out of the central core of a seven-core fiber (SCF) and holds a solid pendulum. Six parallel Fabry-Perot interferometers formed between the SCF. The pendulum transforms variations in cavity length caused by pitching and rolling into the evolution of the interference signal. A fan-in/fan-out device is used to implement space division multiplexing of the SCF, enabling the proposed sensor to judge direction. We also develop a mathematical expression to explain the association between the pitching and rolling angles and the WI-FAS output signals. Mechanical simulations are carried out to investigate the primary factors that affect the sensitivity. With optimum settings, the proposed WI-FAS achieves continuous and simultaneous monitoring of pitching and rolling with a sensitivity of greater than 0.13 nm/
$^\circ$
in the angle range of
$-180 ^\circ$
to
$+180 ^\circ$
. The suggested WI-FAS exhibits the advantages of compact size, high sensitivity, and has the ability to monitor pitching and rolling simultaneously. Thus it is a competitive candidate in the field of attitude sensing.