动热源摆式单轴MEMS热加速度计敏感机理的研究

Study on Sensing Mechanism of Single-Axis MEMS Thermal Accelerometer with Dynamic Heat Source Pendulum

该文揭示了一种动热源摆式单轴微机电系统(MEMS)热加速度计的敏感机理。在给出敏感结构原理的基础上,通过建立二维物理研究模型、划分网格、加载加速度等方法对敏感结构内的温度场进行了计算。结果表明,开机1.8 s后在敏感结构内形成了一个稳定的以动热源为中心的温度场;输入加速度a时,动热源沿着加速度方向偏移,温度场随之偏移,敏感轴方向上对称设置的两个热线温差ΔT X随着输入加速度a的加大而呈线性增长,温度灵敏度为7.1×10^(-2)mK/g。根据输入-输出(a-V X OUT)特性曲线给出数学模型,得到该加速度计灵敏度为0.5 V/g,非线性度为2.8%,从而揭示了敏感机理。

The sensing mechanism of a dynamic thermal source pendulum single-axis MEMS thermal accelerometer was revealed in this paper.Based on the principle of the sensitive structure,the temperature field inside the sensitive structure is calculated by establishing the two-dimensional physical research model,meshing the grid,loading the acceleration and other methods.The results show that a stable temperature field centered at the dynamic heat source is formed within the sensitive structure after 1.8 s of power-on.When inputting the acceleration a,the dynamic heat source shifts along the direction of acceleration,then the temperature field is shifted.The temperature differenceΔT X between the two hot lines symmetrically set in the direction of sensitive axis increases linearly with the increase of input acceleration a,and the temperature sensitivity is 7.1×10^(-2) mK/g.According to the input-output characteristic a-V X OUT curve,the mathematical model is given,and the sensitivity of accelerometer is 0.5 V/g,and the nonlinearity is 2.8%,which reveals the sensing mechanism.