Calibration of a Load Measurement System for an Unmanned Aircraft Composite Wing Based on Fibre Bragg Gratings and Electrical Strain Gauges

Abstract

This paper presents the issues concerning calibration of a measurement system for monitoring the cross-sectional forces and moments of an unmanned aircraft’s wing. A composite cantilever wing with built-in measurement systems based on electrical resistance and Fibre Bragg Grating strain gauges has been made for the purpose of the study. Measurement systems placed along the span of the wing consist of strain gauges arranged in a manner that allows the monitoring of shear force, bending and twisting moments. The calibration process was described in terms of both experimental tests and mathematical formalism. The calibration results were compared for the complete system, consisting of three sensor units, and for various combinations of separated measuring points. For each case, a reading inaccuracy analysis was carried out and conclusions, including recommendations for the design of this kind of measurement system, were formulated.