Coupled Dynamic Analysis and Decoupling Optimization Method of the Laser Gyro Inertial Measurement Unit

Abstract

The mechanical dithered ring laser gyro (RLG) effectively overcomes the lock-in effect and ensures the sensitive accuracy of the low angular rate for the gyro. However, in the inertial measurement unit (IMU) system, the dither excitation of three RLGs causes the coupled vibration of the IMU structure, which could seriously limit the measuring accuracy of RLGs. In this paper, the vibration frequency response characteristic of laser gyro IMU is taken as the focus point, and the method of multi-rigid body dynamics is used to establish the dynamic model of IMU suitable for vibration frequency response analysis. On the basis of the model, the multi-degree-of-freedom coupling vibration of IMU with the gyro dither excitation is clearly described. A new IMU dynamic decoupling optimization method is proposed to minimize the coupled vibration frequency response, and compared with the previous optimal design method. The prototype experimental test results show that the coupled vibration of IMU is restrained more effectively by the proposed new method than by the previous optimal design method. Finally, on the basis of this new method, the measuring accuracy of the RLGs in the IMU system is improved, which is quite useful for practical engineering application.

Zero-bias error compensation method of laser gyro based on neural network

“…RBF function is a nonlinear Gaussian radial basis function, and the function is a radial symmetric function. If the distance between the data input and the symmetry centre is farther, the output of the hidden layer is smaller; On the contrary, the larger the output value of hidden layer nodes (Fang et al, 2020;Andre et al, 2019)…”

“…At present, the commonly used error modelling methods of laser gyro include time series method, wavelet network, neural network and so on. At the same time, the temperature error model in the temperature compensation method of laser gyroscope can effectively realise the real-time temperature compensation of laser gyroscope (Klimkovich, 2021;Chen, 2022;Fang et al, 2020). In view of this, a neural network oriented zero deviation compensation model of laser gyroscope is proposed and compared with the improved model, in order to improve the temperature compensation effect of laser gyroscope in China.…”

The Application of the Vibration Absorber in Laser Inertial Navigation Products

“…To eliminate the lockin effect, dither is involved in the operation of DRLG [1][2][3]. However, dithering coupled noise causes the accuracy of DRLG to sharply decrease in products [4]. The origin of dithering coupled noise is that the dither of one gyro excited the platform to dither, which changes the dynamic state of the other DRLG.…”