Experimental research of helicopter blade load in flight based on optical sensing

Abstract The actual flight measurement of blade load is an extremely important part of the new helicopter. In order to solve the problems existing in the traditional electrical measurement method, such as weak anti-interference ability, short life, and large added mass, a flight measurement method of blade load based on optical sensing is proposed. Firstly, the strain mode distribution law is obtained by calculating the dynamic response of the real blade. The optimal layout of the optical fiber measurement points is determined. Through theoretical analysis of strain transferring and experimental verification, a highly reliable fusion scheme of blade and fiber is designed to meet the flight requirements. Based on the power line carrier technology, the optical sensing test system for helicopter flight test is developed. The flight test of blade load is completed successfully. The results of optical fiber measurement are consistent with the results of traditional electrical measurement, which indicates that the optical sensing technology has good applicability in the measurement of helicopter blade load. At the same time, it has been proved that the optical measurement system set is reliable and durable. It is of great significance for the leap from electric measurement to optical measurement.