Liu Shi Qiang, Zhu Rong
State Key Laboratory of Precision Measurement Technology and Instrument, Department of Precision Instruments, Tsinghua University, Beijing 100084, China.
Sensors (Basel). 2016 Jan 29;16(2):175. doi: 10.3390/s16020175.
Errors compensation of micromachined-inertial-measurement-units (MIMU) is essential in practical applications. This paper presents a new compensation method using a neural-network-based identification for MIMU, which capably solves the universal problems of cross-coupling, misalignment, eccentricity, and other deterministic errors existing in a three-dimensional integrated system. Using a neural network to model a complex multivariate and nonlinear coupling system, the errors could be readily compensated through a comprehensive calibration. In this paper, we also present a thermal-gas MIMU based on thermal expansion, which measures three-axis angular rates and three-axis accelerations using only three thermal-gas inertial sensors, each of which capably measures one-axis angular rate and one-axis acceleration simultaneously in one chip. The developed MIMU (100 × 100 × 100 mm³) possesses the advantages of simple structure, high shock resistance, and large measuring ranges (three-axes angular rates of ±4000°/s and three-axes accelerations of ± 10 g) compared with conventional MIMU, due to using gas medium instead of mechanical proof mass as the key moving and sensing elements. However, the gas MIMU suffers from cross-coupling effects, which corrupt the system accuracy. The proposed compensation method is, therefore, applied to compensate the system errors of the MIMU. Experiments validate the effectiveness of the compensation, and the measurement errors of three-axis angular rates and three-axis accelerations are reduced to less than 1% and 3% of uncompensated errors in the rotation range of ±600°/s and the acceleration range of ± 1 g, respectively.
微机电惯性测量单元（MIMU）的误差补偿在实际应用中至关重要。本文提出了一种基于神经网络识别的MIMU新补偿方法，该方法能够解决三维集成系统中存在的交叉耦合、失准、偏心及其他确定性误差等普遍问题。利用神经网络对复杂的多变量非线性耦合系统进行建模，通过全面校准可轻松补偿误差。本文还提出了一种基于热膨胀的热气体MIMU，它仅使用三个热气体惯性传感器来测量三轴角速率和三轴加速度，每个传感器能够在一个芯片中同时测量一个轴的角速率和一个轴的加速度。与传统MIMU相比，所开发的MIMU（100×100×100 mm³）具有结构简单、抗冲击性强和测量范围大（三轴角速率为±4000°/s，三轴加速度为±10 g）的优点，这是因为使用气体介质代替机械质量块作为关键的运动和传感元件。然而，气体MIMU存在交叉耦合效应，会影响系统精度。因此，所提出的补偿方法被应用于补偿MIMU的系统误差。实验验证了补偿的有效性，在±600°/s的旋转范围和±1 g的加速度范围内，三轴角速率和三轴加速度的测量误差分别降低到未补偿误差的1%和3%以下。
