基于AD7746的电容法间隙测量应用系统研究

为精确测量航空发动机部件间隙,针对电容法间隙测量进行了应用研究,重点设计了基于可编程电容—数字转换器AD7746的电容法间隙测量应用系统。采用驱动电缆法等措施,以减小寄生电容,提高抗干扰能力,并通过对AD7746内部可编程寄存器的补偿设置实现宽范围、高精度测量。该系统在自行设计的实验台架上进行多次实验,表明系统具有较好的线性度、重复性和较高的测量精度。最后,提出了电容法测量发动机叶尖间隙的方案。

Study on capacitance method clearance measurement application system based on AD7746

In order to measure aero-engine parts'clearance precisely,an application research on capacitance method clearance measurement is carried out,and it mainly designs a capacitance method clearance measurement application system based on the programmable capacitance-digital converter AD7746.Driven cable is used to avoid parasitic capacitance's influence on measuring results and enhance its anti-jamming ability,wide measurement range and high precision can be achieved by configuring compensation registers of AD7746.This system is tested many times on the own-designed experiment platform,which shows that expected targets are achieved with nice linearity,good repeatability and high precision.Finally a scheme of engine's tip clearance measurement by capacitance method is given.