New Incentive System Of Resonant Fuel Density Meter

Aircraft fuel density measurement is an important part of many aircraftparameter measurement. In order to improve the aircraft’s endurance ability, it is veryimportant to achieve the online high precision fuel density measurement. After severalyears of research, our laboratory developed a high-performance aircraft fuel densitysensor, which can meet the above requirements, and has been accepted by ChinaAviation Industry609. Trying to make the sensors to be products, this article usesDSP+FPGA architecture which has much more powerful computing capability,replaces the C8051F021microcontroller to achieve a more flexible control andadjustment.This paper mainly completed the following work：(1) Expound the resonant cylinder fuel density sensor (CFDS)’s workingprinciples well as the realization conditions; Analysis of the resonant characteristics ofthe resonant circuit, and find out the amplitude relationship and phase relationship toguide to adjust the circuit.(2) Design hardware circuit system to meet resonance condition, and set uparchitecture based on DSP and FPGA; realized the function such as automaticadjustment of the gain and phase, the filter and impedance measurement by software.(3) Realized resonance by the use of positive feedback principle and cooperatedwith local negative feedback. When the quality factor of system is low, for the firsttime, we use phase difference as a resonance frequency adjustment basis. Realizedexperiment from each module to the whole excitation system.The advantage of this system:①the flexibility of the AGC: The outputamplitude and gain size can be adjusted by modifying the software at any time, so thatit can be applied to more sensors.②it can achieve360°of the phase adjustment, inorder to meet the resonance condition.③using the principle of local negativefeedback, so that the circuit is stable.④a more accurate parameter compensation canbe realized by more powerful computing control ability.Experiments indicated that the system implemented the core functionality of theoriginal system: automatic gain adjustment and automatic phase adjustment function,and can achieve filtering functions; possessed a resonant the fuel density sensorexcitation system of the basic conditions.