对称单质量微机电陀螺的零偏自补偿方法

Bias self-compensation method for single-mass MEMS gyroscope with symmetric structure

针对微机电陀螺的零偏易受环境因素如温度的影响而发生漂移的问题,提出了一种适用于全对称单质量陀螺的零偏自补偿方法,该方法以两种基本单轴工作模式为基础,将两种工作模式下的检测信号进行差分即可实现零偏自补偿。建立了陀螺的动力学模型,对于结构完全对称的单质量陀螺,得出了两种基本工作模式对应的标度因数互为相反数、温度变化引起的零偏变化量一致的结论,并通过实验得到了验证。零偏自补偿方法实现了标度因数叠加、零偏变化量抵消的效果。设计了一种基于FPGA的零偏自补偿数字电路,并进行了零偏试验。零偏温度试验结果表明,在25℃~70℃的温度范围内,两种基本工作模式对应的零偏输出随温度变化的趋势一致,零偏自补偿后的零偏变化量降为了基本工作模式的24%;常温零偏试验结果表明,零偏自补偿后的陀螺零偏稳定性和零偏不稳定性分别抑制到了基本单轴工作模式的18%和31.85%,验证了该零偏自补偿方法的有效性。

The bias of MEMS gyroscope is liable to be affected by environment factors such as temperature. To solve this problem, a bias self-compensation method for single-mass gyroscope with symmetric structure is proposed, which is based on two basic single-axis work patterns and realize the bias autocompensation by means of the differential signal of the sense outputs in basic work patterns. The dynamic model of gyroscope is established, which shows that, for the single-mass gyroscope with symmetric structure, the scale factors in basic work patterns are opposite, and the bias variations caused by temperature are the same. The conclusions are proved by experiments. The Bias self-compensation method realizes the addition of the basic scale factors and the substation of the basic biases. A bias self-compensation digital circuit is designed, and the bias experiment is carried out. The bias temperature test results show that the basic biases＇ changing trends with temperature are similar, and the bias variation after self-compensation is reduced to 24% of the basic bias variations in 25℃？70℃. The bias test results at room temperature show that the bias stability and bias instability after self-compensation are depressed to 18% and 31.85% respectively, compared with that in basic work patterns.