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过低的灵敏度性能一直是声表面波(SAW)陀螺仪的瓶颈问题,对此,提出了一种结合金属点阵用以改善陀螺效应的新型行波模式SAW陀螺仪,并对其性能进行了评价。该结构由双延迟线型振荡器构成,两延迟线平行且反向制作于同一压电基片上,在延迟线的声传播路径上分布铜点阵。结合层状介质中声波传输特性的研究方法分析了两种压电晶体材料、不同金属点阵膜厚对传感器响应的影响,从而为确定陀螺仪的设计奠定理论基础。基于理论计算结果,研制了以128°YX LiNbO3及X-112°Y LiTaO_3为压电基片,铜点阵厚度分别为3000 A,6000 A,9000 A的95 MHz声表面波陀螺仪。为改善振荡器的频率稳定性,延迟线采用了具有梳状结构的单相单向换能器结构。振荡器的测试频率稳定度达到了±5 Hz/h。利用精确速率转台对所研制的SAW陀螺仪性能进行了测试。测试结果表明:采用机电耦合系数较高的128°YX LiNbO_3基片并增加金属点阵厚度均能有效提高陀螺仪的检测灵敏度,所获得的最大检测灵敏度为2.7 Hz/(deg/s)。
Too low sensitivity performance has always been the bottleneck of SAW gyroscopes. In this regard, a new SAW gyroscope with a combination of metal dots to improve the gyro effect has been proposed and its performance has been studied Evaluation. The structure consists of a double-delay linear oscillator in which two delay lines are fabricated in parallel and oppositely on the same piezoelectric substrate, distributing copper dots on the acoustic propagation path of the delay line. Combined with the research method of acoustic wave transmission in layered media, the influence of two kinds of piezoelectric crystal materials and different metal dot film thickness on the sensor response is analyzed, which lays a theoretical foundation for the determination of gyro design. Based on the theoretical calculation results, a 95 MHz SAW gyro was fabricated with piezoelectric substrates of 128 ° YX LiNbO3 and X-112 ° Y LiTaO_3 with copper lattice thicknesses of 3000 A, 6000 A and 9000 A, respectively. To improve the frequency stability of the oscillator, the delay line uses a single-phase unidirectional transducer structure with a comb-like structure. Oscillator test frequency stability of ± 5 Hz / h. The performance of the developed SAW gyroscope was tested using an accurate turret. The test results show that the detection sensitivity of the gyroscope can be effectively improved by using a 128 ° YX LiNbO_3 substrate with high electromechanical coupling coefficient and increasing the thickness of the metal lattice. The maximum detection sensitivity is 2.7 Hz / (deg / s).