谐振式耦合悬臂梁力传感器设计与检测性能分析

Design and detection performance analysis of resonantcoupled cantilever beam force sensor

谐振式力传感器的检测性能取决于谐振敏感元件的几何尺寸、结构形式和传感机制,目前,单纯依靠减小尺寸提高检测性能的方法已经处于瓶颈期。为了研究发展新型谐振式力传感器,协调非线性振动与谐振结构检测性能之间的矛盾,从而探索灵敏度更高的传感机制,提高其检测性能,提出了一种压电驱动的谐振式磁耦合悬臂梁力传感器。首先,对磁耦合悬臂梁的结构进行了设计和理论建模,通过理论分析了外界压力对磁耦合悬臂梁结构振动特性的影响,随着压力增大,磁耦合悬臂梁之间的距离减小,谐振频率增大。其次,实验验证了分岔跳跃动力学行为的优点,相比单根谐振梁共振时的最大振幅提高了2.8倍,然后研究了基于分岔跳跃特性和基于倍频响应的两种压力检测方案,分别利用分岔跳跃时的临界频率与模态耦合时高阶响应频率实现了压力检测,并对灵敏度和线性度进行了分析。实验结果表明,基于分岔跳跃特性的检测方案振幅变化明显,是基于倍频特性检测方案的5倍左右,易于检测,克服了非线性因素带来的不良影响;基于倍频响应的检测方案输出灵敏度高,是基于分岔跳跃检测方案的4倍左右,信噪比大,为设计不同检测原理的谐振式力传感器提供了一定的参考价值。

The detection performance of resonant force sensor depends on the geometry dimensions,structure configuration and sensing mechanism of the resonant sensitive element.At present,the method of improving the detection performance by simply reducing the size has been in the bottleneck period.In order to study and develop a novel resonant force sensor,coordinate the contradiction between nonlinear vibration and resonant structure detection performance,explore a more sensitive sensing mechanism and improve its detection performance,a piezoelectric driven resonant magnetically coupled cantilever force sensor is proposed.Firstly,the design and theoretical modeling of the structure of the magnetically coupled cantilever beam are carried out.The influence of the external pressure on the vibration characteristics of the magnetically coupled cantilever beam structure is analyzed theoretically.With the increase of the pressure,the distance between the magnetically coupled cantilever beams decreases and the resonance frequency increases.Secondly,the experiment verifies the advantages of the bifurcation jump dynamic behavior,which increases the maximum amplitude by 2.8 times compared with the resonance of a single resonant beam.Then,two pressure detection schemes based on the bifurcation jump characteristics and frequency doubling response are studied,and the pressure detection is realized by using the critical frequency of the bifurcation jump and the high order response frequency when the mode is coupled.The sensitivity and linearity are analyzed.The experimental results show that the amplitude change of the detection scheme based on the bifurcation jump characteristic is obvious,which is about 5 times that of the detection scheme based on the frequency doubling characteristic,and it is easy to detect and overcome the adverse effects of nonlinear factors.The detection scheme based on frequency doubling response has high output sensitivity,which is about 4 times that of the detection scheme based on bifurcation jump,and large signal-to-noise ratio,which provides a certain reference value for designing resonant force sensors with different detection principles.