阅读说明：本技术 一种激光陀螺双轴旋转惯导系统姿态误差补偿方法 (Attitude error compensation method for laser gyro double-shaft rotation inertial navigation system ) 是由 蔡庆中 涂勇强 杨功流 刘洋 孙艺丁 于 2019-07-31 设计创作，主要内容包括：本发明公开了一种激光陀螺双轴旋转惯导系统姿态误差补偿方法,依次通过构建激光陀螺双轴旋转惯导系统的六自由度动力学模型,获得内框轴和外框轴旋转时的动力学方程,并利用四阶龙格-库塔法求解得到内/外框轴旋转时由橡胶减振器变形造成的偏差角,对通过动力学分析得到的框架轴角速率与橡胶减振器变形产生的偏差角的对应关系进行拟合得到姿态误差补偿信息；以及根据姿态误差补偿信息补偿姿态输出实现；该姿态误差补偿方法能够有效提高激光陀螺双轴旋转惯导系统的姿态精度的目的,经过误差补偿的姿态与原有未补偿的姿态输出相比,纵摇角和航向角的输出精度可提高约8倍,充分证明了该方法的有效性。(The invention discloses an attitude error compensation method of a laser gyro double-shaft rotation inertial navigation system, which comprises the steps of sequentially constructing a six-degree-of-freedom dynamic model of the laser gyro double-shaft rotation inertial navigation system, obtaining a dynamic equation when an inner frame shaft and an outer frame shaft rotate, solving by utilizing a four-order Runge-Kutta method to obtain a deviation angle caused by the deformation of a rubber shock absorber when the inner/outer frame shaft rotates, and fitting the corresponding relation between the frame shaft angular rate obtained through dynamic analysis and the deviation angle generated by the deformation of the rubber shock absorber to obtain attitude error compensation information; compensating attitude output according to the attitude error compensation information; the attitude error compensation method can effectively improve the attitude accuracy of the laser gyro biaxial rotation inertial navigation system, compared with the output of the original uncompensated attitude, the output accuracy of the longitudinal rocking angle and the course angle can be improved by about 8 times, and the effectiveness of the method is fully proved.)

1. a method for compensating attitude errors of a laser gyro biaxial rotation inertial navigation system is characterized by comprising the following steps:

S1, constructing a three-dimensional rigidity damping model for each rubber shock absorber, and constructing a six-degree-of-freedom dynamic model of the laser gyro biaxial rotation inertial navigation system by replacing 8 rubber shock absorbers with 8 three-dimensional rigidity damping models;

S2, respectively obtaining kinetic equations when the inner frame shaft and the outer frame shaft rotate by utilizing a six-degree-of-freedom kinetic model of the laser gyro biaxial rotation inertial navigation system constructed in the step S1, and solving by utilizing a fourth-order Runge-Kutta method to obtain a deviation angle caused by deformation of the rubber shock absorber when the inner frame shaft and the outer frame shaft rotate;

s3, fitting the corresponding relation between the frame shaft angular rate obtained through the dynamic analysis and the deviation angle generated by the deformation of the rubber shock absorber to obtain attitude error compensation information;

And S4, compensating the attitude output of the laser gyro biaxial rotation inertial navigation system according to the attitude error compensation information.

2. The method for compensating the attitude error of the laser gyro biaxial rotational inertial navigation system according to claim 1, wherein the step S1 specifically comprises the steps of:

S101, constructing a three-dimensional stiffness damping model for each rubber shock absorber, and defining physical parameters of the three-dimensional stiffness damping model of the rubber shock absorber: unidirectional stiffness k and unidirectional damping c;

construction of inertial measurement Unit coordinate System CO-x_my_mz_mAnd the virtual inertial measurement unit coordinate system COs-x_msy_msz_mswherein CO is the center of mass of the inertial measurement unit, CO-x_my_mz_mAre parallel to the axis of symmetry of the inertial measurement unit; COs-x_msy_msz_msFor assuming the corresponding CO-x when the rubber vibration damper is not deformed_my_mz_mA coordinate system which is a virtual coordinate system;

S103, in the laser gyro biaxial rotation inertial navigation system, an outer frame is arranged on a support frame through an outer frame shaft system, an inner frame is arranged on the outer frame through an inner frame shaft system, and an inertia measuring device is fixed on the inner frame through 8 rubber vibration dampers A, B, C, D, E, F, G and H; thus, further, the mass of the inertial measurement unit is defined as m, which is relative to the axis CO-x_m,CO-y_mwith CO-z_mRespectively is I_x,I_yAnd I_z(ii) a 8 rubber vibration dampers A, B, C, D, E, F, G and H are arranged in a coordinate system CO-x_my_mz_mCoordinate of (x)_A,y_A,z_A)，(x_B,y_B,z_B)，(x_C,y_C,z_C)，(x_D,y_D,z_D)，(x_E,y_E,z_E)，(x_F,y_F,z_F)，(x_G,y_G,z_G)，(x_H,y_H,z_H)；

S104, defining a deviation angle θ ═ α β γ due to deformation of the rubber damper]^Twherein alpha, beta and gamma are respectively coordinate system CO-x_my_mz_mAnd coordinate system COs-x_msy_msz_msAbout an axis COs-x_ms，COs-y_ms，COs-z_msThe deviation angle of (d); defining the center of mass movement r ═ x y z caused by deformation of rubber vibration damper]^Twherein x, y and z are coordinate systems CO-x respectively_my_mz_mAnd coordinate system COs-x_msy_msz_msAbout axis COs-x_ms，COs-y_ms，COs-z_msdisplacement of (2);

And S105, representing the rubber shock absorber by the constructed three-dimensional rigidity damping model according to the deviation angle and the definition of each physical parameter, and constructing a six-degree-of-freedom dynamic model of the laser gyro biaxial rotation inertial navigation system.

3. The method for compensating the attitude error of the laser gyro biaxial rotational inertial navigation system according to claim 1, wherein the step S2 specifically comprises the steps of:

(1) When the inner frame shaft of the double-shaft rotating mechanism rotates and the outer frame shaft does not rotate, the six-degree-of-freedom dynamic model is simplified into a three-degree-of-freedom dynamic model which only considers x, y and gamma in a plane vertical to the inner frame shaft, and the dynamic equation is as follows:

z＝0；

α＝0；

β＝0；

The rotation angular rate omega of the inner frame shaft and the outer frame shaft_iAnd ω_osubstituting the parameters into a kinetic equation, and solving the kinetic equation through a fourth-order Runge-Kutta algorithm to obtain deviation angles alpha, beta and gamma generated by deformation of the rubber shock absorber;

(2) when the outer frame shaft of the double-shaft rotating mechanism rotates and the inner frame shaft does not rotate, the six-degree-of-freedom dynamic model is simplified into a three-degree-of-freedom dynamic model which only considers x, z and beta in a plane vertical to the outer frame shaft, and the dynamic equation is as follows:

y＝0；

α＝0；

γ＝0；

the rotation angular rate omega of the inner frame shaft and the outer frame shaft_iand ω_osubstituting the parameters into a kinetic equation, and solving the kinetic equation through a fourth-order Runge-Kutta algorithm to obtain deviation angles alpha, beta and gamma generated by deformation of the rubber shock absorber;

Wherein the deviation angles alpha, beta and gamma are respectively a coordinate system CO-x of the inertial measurement unit_my_mz_mAnd the virtual inertial measurement unit coordinate system COs-x_msy_msz_msAbout an axis COs-x_ms，COs-y_ms，COs-z_msThe angle of deviation of (c).

4. The method of claim 3, wherein in step S2, the rotation angular rates ω of the inner frame axis and the outer frame axis are determined according to the rotation angular rates ω_iAnd ω_oparticularly, the angular encoders arranged on the inner frame shaft and the outer frame shaft measure in real time to obtain the rotation angular rate omega of the motor of the inner frame shaft_iAnd angular velocity ω of rotation of outer frame axis motor_o。

5. The method for compensating the attitude error of the laser gyro biaxial rotational inertial navigation system according to claim 1, wherein the step S3 specifically comprises the steps of:

(1) when the inner frame shaft of the biaxial rotation mechanism rotates and the outer frame shaft does not rotate, the rotation angular rate omega of the inner frame shaft_iWith deviation angle γ according to the formula:Fitting to obtain fitting parameters a, b, c and d;

Further, the attitude error compensation information is obtained according to the fitting parameters as follows:

Δα＝0；

in the formula, delta alpha, delta beta and delta gamma are error compensation information of a roll angle, a pitch angle and a course angle of the biaxial rotation inertial navigation system respectively;

(2) when the outer frame shaft of the double-shaft rotating mechanism rotates and the inner frame shaft does not rotate, the rotation angular rate of the outer frame shaft is omega_oWith deviation angle γ according to the formula:Fitting to obtain fitting parameters e, f, g and h;

Further, the attitude error compensation information is obtained according to the fitting parameters as follows:

Δα＝0；

In the formula, Δ α, Δ β, and Δ γ are respectively yaw angle error compensation information, pitch angle error compensation information, and course angle error compensation information of the biaxial rotational inertial navigation system.

6. the method for compensating the attitude error of the laser gyro biaxial rotational inertial navigation system according to claim 1, wherein the step S4 specifically comprises the steps of:

S401, acquiring an inertial signal of the navigation resolving plate based on an inertial measurement unit to obtain attitude output of the inertial navigation system: roll angle theta, pitch angle thetaand a course angle phi;

S402, obtaining the roll angle theta and the pitch angle of the inertial navigation system obtained in the step S401And the course angle phi, the error compensation information of the roll angle, the pitch angle and the course angle of the double-shaft rotary inertial navigation system obtained in the step S3, and the angular encoders arranged on the inner frame shaft and the outer frame shaft to measure in real time to obtain the rotation angular rate omega of the motor of the inner frame shaft_iAnd angular velocity ω of rotation of outer frame axis motor_oSubstituting into the following equation:

θ_c＝θ；

obtaining the attitude output after real-time compensation, i.e. the compensated roll angle theta_cCompensated pitch angleAnd compensated course angle phi_c。

Technical Field

The invention relates to the technical field of attitude error compensation of a rotary inertial navigation system, in particular to an attitude error compensation method of a laser gyro double-shaft rotary inertial navigation system.

background

the inertial measurement unit is a core component of the inertial navigation system, and provides inertial device information (three-dimensional acceleration and three-dimensional angular velocity information relative to the inertial system) of a carrier to the inertial navigation system through the orthogonally mounted three-axis gyro assembly and three-axis accelerometer assembly. And a navigation computer board of the inertial navigation system performs navigation calculation on the inertial device information to obtain real-time navigation information of the carrier including position, speed and attitude information. Because the navigation calculation method of the inertial system is based on the dead reckoning principle, the precision of the inertial system is limited by the zero offset error of an inertial device and is accumulated along with time. In order to solve the problem that the navigation error of the inertial navigation system is accumulated along with time, the rotary inertial navigation system enables the inertial measurement unit to periodically rotate around the symmetrical axis of the inertial measurement unit by the aid of the rotary mechanism to modulate the zero offset error, and accuracy of the inertial navigation system is greatly improved. In view of accuracy, cost, and mechanism reliability, the dual-axis rotation mechanism is widely used in a high-accuracy rotary inertial navigation system. Meanwhile, in order to avoid the influence of the rotary motion of the rotary mechanism on the precision of the gyroscope, a laser gyroscope with stable scale performance is adopted to form a triaxial gyroscope assembly in the inertial measurement unit. Therefore, the laser gyro biaxial rotation inertial navigation system is a typical high-precision navigation device at present. In practical use, in order to avoid the influence of the jitter device of the laser gyroscope on the gyroscope precision, the laser gyroscope inertia measurement device must be provided with a vibration reduction system, and the common mode is to mount the laser gyroscope inertia measurement device on the inner frame of the biaxial rotation mechanism through 8 rubber vibration dampers in a spatial 8-point layout.

Although the double-shaft rotating mechanism greatly improves the accuracy of the inertial system, the introduction of the double-shaft rotating mechanism brings about deviation angles between the double-shaft rotating mechanism and the inertial measurement unit, which include fixed mounting errors between the double-shaft rotating mechanism and the inertial measurement unit and deviation angles due to deformation of the rubber damper. The deviation angle seriously reduces the attitude accuracy of the biaxial rotary inertial navigation system, and in order to overcome the influence of the deviation angle, the published patent CN104121926A provides a calibration method for the installation error angle between the rotating shaft and the sensitive shaft of the biaxial rotary inertial navigation system, and the published patent CN109211269A provides a calibration method for the attitude error angle of the biaxial rotary inertial navigation system, however, although these methods perfectly solve the attitude error caused by the deviation angle generated by the fixed installation error between the biaxial rotating mechanism and the inertial measurement unit, these methods cannot solve the influence of the deviation angle generated by the deformation of the rubber shock absorber in the laser gyro biaxial rotary inertial navigation system on the attitude accuracy.

therefore, in order to overcome the influence of the deviation angle generated by the deformation of the rubber damper in the laser gyro dual-axis rotational inertial navigation system on the attitude accuracy and further improve the attitude accuracy of the laser gyro dual-axis rotational inertial navigation system, it is necessary to compensate for the attitude error caused by the deviation angle generated by the deformation of the rubber damper in the laser gyro dual-axis rotational inertial navigation system.

Disclosure of Invention

the invention aims to provide a laser gyro biaxial rotational inertial navigation system attitude error compensation method which obtains a determined relation between a rotation angular rate and a deviation angle of a rotating mechanism through a dynamics modeling analysis method and a data fitting method so as to provide attitude error compensation information for implementing compensation of system attitude errors.

therefore, the technical scheme of the invention is as follows:

an attitude error compensation method for a laser gyro biaxial rotation inertial navigation system comprises the following steps:

1. a method for compensating attitude errors of a laser gyro biaxial rotation inertial navigation system is characterized by comprising the following steps:

s1, constructing a three-dimensional rigidity damping model for each rubber shock absorber, and constructing a six-degree-of-freedom dynamic model of the laser gyro biaxial rotation inertial navigation system by replacing 8 rubber shock absorbers with 8 three-dimensional rigidity damping models;

S2, respectively obtaining kinetic equations when the inner frame shaft and the outer frame shaft rotate by utilizing a six-degree-of-freedom kinetic model of the laser gyro biaxial rotation inertial navigation system constructed in the step S1, and solving by utilizing a fourth-order Runge-Kutta method to obtain a deviation angle caused by deformation of the rubber shock absorber when the inner frame shaft and the outer frame shaft rotate;

S3, fitting the corresponding relation between the frame shaft angular rate obtained through the dynamic analysis and the deviation angle generated by the deformation of the rubber shock absorber to obtain attitude error compensation information;

And S4, compensating the attitude output of the laser gyro biaxial rotation inertial navigation system according to the attitude error compensation information.

Further, the specific step of step S1 is:

S101, constructing a three-dimensional stiffness damping model for each rubber shock absorber, and defining physical parameters of the three-dimensional stiffness damping model of the rubber shock absorber: unidirectional stiffness k and unidirectional damping c;

construction of inertial measurement Unit coordinate System CO-x_my_mz_mAnd the virtual inertial measurement unit coordinate system COs-x_msy_msz_mswherein CO is the center of mass of the inertial measurement unit, CO-x_my_mz_mAre parallel to the axis of symmetry of the inertial measurement unit; COs-x_msy_msz_msFor assuming the corresponding CO-x when the rubber vibration damper is not deformed_my_mz_mA coordinate system which is a virtual coordinate system;

S103, in the laser gyro biaxial rotation inertial navigation system, an outer frame is arranged on a support frame through an outer frame shaft system, an inner frame is arranged on the outer frame through an inner frame shaft system, and an inertial measurement device is fixed on the inner frame through 8 rubber vibration dampers A, B, C, D, E, F, G and H; thus, further, the mass of the inertial measurement unit is defined as m, which is relative to the axis CO-x_m,CO-y_mwith CO-z_mrespectively is I_x,I_yAnd I_z(ii) a 8 rubber vibration dampers A, B, C, D, E, F, G and H are arranged in a coordinate system CO-x_my_mz_mcoordinate of (x)_A,y_A,z_A)， (x_B,y_B,z_B)，(x_C,y_C,z_C)，(x_D,y_D,z_D)，(x_E,y_E,z_E)，(x_F,y_F,z_F)，(x_G,y_G,z_G)，(x_H,y_H,z_H)；

s104, defining a deviation angle θ ═ α β γ due to deformation of the rubber damper]^TWherein alpha, beta and gamma are respectively coordinate system CO-x_my_mz_mAnd coordinate system COs-x_msy_msz_msAbout an axis COs-x_ms，COs-y_ms，COs-z_msThe deviation angle of (d); defining the center of mass movement r ═ x y z caused by deformation of rubber vibration damper]^TWherein x, y and z are coordinate system CO-x respectively_my_mz_mand coordinate system COs-x_msy_msz_msAbout axis COs-x_ms，COs-y_ms，COs-z_msDisplacement of (2);

And S105, representing the rubber shock absorber by the constructed three-dimensional rigidity damping model according to the deviation angle and the definition of each physical parameter, and constructing a six-degree-of-freedom dynamic model of the laser gyro biaxial rotation inertial navigation system.

Further, the specific step of step S2 is:

(1) When the inner frame shaft of the double-shaft rotating mechanism rotates and the outer frame shaft does not rotate, the six-degree-of-freedom dynamic model is simplified into a three-degree-of-freedom dynamic model which only considers x, y and gamma in a plane vertical to the inner frame shaft, and the dynamic equation is as follows:

z＝0；

α＝0；

β＝0；

The rotation angular rate omega of the inner frame shaft and the outer frame shaft_iAnd ω_oSubstituting the parameters into a kinetic equation, and solving the kinetic equation through a fourth-order Runge-Kutta algorithm to obtain deviation angles alpha, beta and gamma generated by deformation of the rubber shock absorber;

(2) when the outer frame shaft of the double-shaft rotating mechanism rotates and the inner frame shaft does not rotate, the six-degree-of-freedom dynamic model is simplified into a three-degree-of-freedom dynamic model which only considers x, z and beta in a plane vertical to the outer frame shaft, and the dynamic equation is as follows:

y＝0；

α＝0；

γ＝0；

The rotation angular rate omega of the inner frame shaft and the outer frame shaft_iand ω_oSubstituting the parameters into a kinetic equation, and solving the kinetic equation through a fourth-order Runge-Kutta algorithm to obtain deviation angles alpha, beta and gamma generated by deformation of the rubber shock absorber;

Wherein the deviation angles alpha, beta and gamma are respectively a coordinate system CO-x of the inertial measurement unit_my_mz_mAnd the virtual inertial measurement unit coordinate system COs-x_msy_msz_msAbout an axis COs-x_ms，COs-y_ms，COs-z_msThe angle of deviation of (c).

further, in step S2, the rotation angular rates ω of the inner frame axis and the outer frame axis_iAnd ω_oParticularly, the angular encoders arranged on the inner frame shaft and the outer frame shaft measure in real time to obtain the rotation angular rate omega of the motor of the inner frame shaft_iAnd angular velocity ω of rotation of outer frame axis motor_o。

further, the specific step of step S3 is:

(1) When the inner frame shaft of the biaxial rotation mechanism rotates and the outer frame shaft does not rotate, the rotation angular rate omega of the inner frame shaft_iWith deviation angle γ according to the formula:Fitting to obtain fitting parameters a, b, c and d;

Further, the attitude error compensation information is obtained according to the fitting parameters as follows:

Δα＝0；

in the formula, delta alpha, delta beta and delta gamma are respectively yaw angle error compensation information, pitch angle error compensation information and course angle error compensation information of the biaxial rotation inertial navigation system;

(2) When the outer frame shaft of the double-shaft rotating mechanism rotates and the inner frame shaft does not rotate, the rotation angular rate of the outer frame shaft is omega_oWith deviation angle γ according to the formula:Fitting to obtain fitting parameters e, f, g and h;

Further, the attitude error compensation information is obtained according to the fitting parameters as follows:

Δα＝0；

In the formula, Δ α, Δ β, and Δ γ are error compensation information of a roll angle, a pitch angle, and a course angle of the biaxial rotational inertial navigation system, respectively.

Further, the specific step of step S4 is:

s401, acquiring an inertial signal of the navigation resolving plate based on an inertial measurement unit to obtain an attitude output of the inertial navigation system: roll angle theta, pitch angle thetaAnd a course angle phi;

S402, obtaining the roll angle theta and the pitch angle of the inertial navigation system obtained in the step S401And a course angle phi, the roll angle error compensation information, the pitch angle error compensation information and the course angle error compensation information of the biaxial rotational inertial navigation system obtained in the step S3, and an angle encoder arranged on the inner frame shaft and the outer frame shaft to measure in real time to obtain the rotation angular rate omega of the motor of the inner frame shaft_iAnd angular velocity ω of rotation of outer frame axis motor_oSubstituting into the following equation:

θ_c＝θ；

drawing (A)

Obtaining the attitude output after real-time compensation, i.e. the compensated roll angle theta_cCompensated pitch angleand compensated course angle phi_c。

Compared with the prior art, the beneficial effect of this application lies in:

(1) The attitude error compensation method for the laser gyro biaxial rotation inertial navigation system is clear in mechanism, the determination relation between the rotation angular rate and the deviation angle of the rotation mechanism is obtained through a dynamics modeling analysis method and a data fitting method, attitude error compensation information is given, the purpose of improving the attitude accuracy of the laser gyro biaxial rotation inertial navigation system is achieved, and the method is high in pertinence.

(2) According to the attitude compensation method, the error compensation model used in the process of compensating the output attitude is processed in advance, and the compensation model is also in a simple polynomial form and is suitable for real-time calculation, so that the method is easy to implement in the working process of an actual system, and can meet the real-time requirement of engineering application.

(3) The attitude error compensation method provided by the application has a remarkable effect. The method compensates the errors of the longitudinal rocking angle and the heading angle except that the rubber shock absorber is deformed and does not obviously affect the errors of the transverse rocking angle and not compensate the errors of the transverse rocking angle, compared the error-compensated attitude with the output of the original uncompensated attitude, the output accuracy of the longitudinal rocking angle and the heading angle can be improved by about 8 times, and the effectiveness of the method is fully proved.

Drawings

FIG. 1 is a flow chart of an attitude error compensation method of a laser gyro biaxial rotation inertial navigation system according to the present invention;

FIG. 2(a) is a schematic diagram of the z-axis direction of a three-dimensional stiffness damping model of a single rubber vibration damper of the present invention;

FIG. 2(b) is a schematic diagram of the x-axis and y-axis directions of a three-dimensional stiffness damping model of a single rubber vibration damper of the present invention;

FIG. 3 is a schematic illustration of a three-dimensional stiffness damping model of a single rubber shock absorber of the present invention;

FIG. 4 is a schematic diagram of a six-degree-of-freedom dynamics model constructed in the method for compensating the attitude error of the laser gyro biaxial rotational inertial navigation system according to the present invention;

FIG. 5 is a schematic diagram of a three-degree-of-freedom dynamic model obtained by simplifying a six-degree-of-freedom dynamic model in an attitude error compensation method of a laser gyro biaxial rotational inertial navigation system in a state that an inner frame shaft rotates and the outer frame shaft is static;

FIG. 6 is a schematic diagram of a three-degree-of-freedom dynamic model obtained by simplifying a six-degree-of-freedom dynamic model in an attitude error compensation method of a laser gyro biaxial rotational inertial navigation system in a state that an outer frame shaft rotates and an inner frame shaft is static;

FIG. 7 is a flow chart of implementing the method for compensating the attitude output of the laser gyro dual-axis rotational inertial navigation system according to the attitude error compensation information;

FIG. 8(a) is a diagram illustrating a comparison between roll angle compensation in a compensated attitude and an uncompensated attitude according to the attitude error compensation method of the embodiment of the present invention;

FIG. 8(b) is a diagram illustrating a comparison of pitch angle compensation between a compensated attitude and an uncompensated attitude obtained by the attitude error compensation method according to the embodiment of the present invention;

FIG. 8(c) is a comparison diagram of course angle compensation between the compensated attitude and the uncompensated attitude obtained by the attitude error compensation method according to the embodiment of the invention.

Detailed Description

The invention will be further described with reference to the following figures and specific examples, which are not intended to limit the invention in any way.

As shown in fig. 1, by taking 8 rubber dampers disposed between a laser gyro inertia measurement device and an inner frame of a biaxial rotation mechanism as an example in a laser gyro biaxial rotational inertial navigation system, a specific process description is performed on the attitude error compensation method of the present application, and the specific steps are as follows:

s1, constructing a three-dimensional rigidity damping model for each rubber shock absorber, and constructing a six-degree-of-freedom dynamic model of the laser gyro biaxial rotation inertial navigation system by replacing 8 rubber shock absorbers with 8 three-dimensional rigidity damping models;

specifically, the six-degree-of-freedom dynamic model in step S1 is constructed by the following steps:

S101, constructing a three-dimensional stiffness damping model for each rubber shock absorber, and defining physical parameters of the three-dimensional stiffness damping model of the rubber shock absorber: unidirectional stiffness k and unidirectional damping c; specifically, the unidirectional rigidity k of the rubber damper in the embodiment is 120000N/m, and the unidirectional damping c is 50N · s/m.

as shown in fig. 2(a) and 2(b), the specific arrangement directions of the x-axis, the y-axis and the z-axis in the corresponding coordinate system of the three-dimensional stiffness damping model for constructing the single rubber shock absorber are shown; specifically, the x-axis direction is the direction of a connecting line of two mounting holes on the rubber vibration absorber, the z-axis direction is the direction of a central axis of the rubber vibration absorber, and the y-axis direction is the other direction perpendicular to the x-axis;

abstracting three directions of the rubber damper entity into a three-dimensional stiffness damping model based on the directions of the x-axis, the y-axis and the z-axis set in fig. 2(a) and 2(b), as shown in fig. 3; at the moment, each direction is a rigidity damping model with rigidity of k and damping of c;

S102, constructing a coordinate system CO-x of an inertial measurement unit_my_mz_mAnd the virtual inertial measurement unit coordinate system COs-x_msy_msz_msWherein CO is the center of mass of the inertial measurement unit, CO-x_my_mz_mis parallel to the symmetry axis of the inertial measurement unit; COs-x_msy_msz_msFor assuming the corresponding CO-x when the rubber vibration damper is not deformed_my_mz_mA coordinate system which is a virtual coordinate system;

s103, in the laser gyro biaxial rotation inertial navigation system, an outer frame is arranged on a support frame through an outer frame shaft system, an inner frame is arranged on the outer frame through an inner frame shaft system, and an inertial measurement device is fixed on the inner frame through 8 rubber vibration dampers A, B, C, D, E, F, G and H; thus, further, the mass of the inertial measurement unit is defined as m, which is relative to the axis CO-x_m,CO-y_mWith CO-z_mRespectively is I_x,I_yAnd I_z(ii) a 8 rubber vibration dampers A, B, C, D, E, F, G and H are arranged in a coordinate system CO-x_my_mz_mCoordinate of (x)_A,y_A,z_A)， (x_B,y_B,z_B)，(x_C,y_C,z_C)，(x_D,y_D,z_D)，(x_E,y_E,z_E)，(x_F,y_F,z_F)，(x_G,y_G,z_G)，(x_H,y_H,z_H)；

in particular, in the present embodiment, the mass m of the inertial measurement unit is 16.9kg, relative to the axis CO-x_m,CO-y_mWith CO-z_mmoment of inertia I_x,I_yand I_z0.1496,0.1031,0.1130kg · m²(ii) a 8 rubber vibration dampers A, B, C, D, E, F, G and H are arranged in a coordinate system CO-x_my_mz_mthe coordinates in (0.0866, -0.1111,0.0996) m, (-0.0694, -0.1111,0.0996) m, (-0.0694, -0.1111, -0.1104) m, (0.0866, -0.1111, -0.1104) m, (0.0866,0.1149,0.0996) m, (-0.0694,0.1149,0.0996) m, (0.0866,0.1149, -0.1104) m, (-0.0694,0.1149, -0.1104) m;

S104, defining a deviation angle θ ═ α β γ due to deformation of the rubber damper]^TWherein alpha, beta and gamma are respectively coordinate system CO-x_my_mz_mAnd coordinate system COs-x_msy_msz_msAbout an axis COs-x_ms，COs-y_ms，COs-z_msThe deviation angle of (d); defining the center of mass movement r ═ x y z caused by deformation of rubber vibration damper]^Twherein x, y and z are coordinate system CO-x respectively_my_mz_mAnd coordinate system COs-x_msy_msz_msAbout axis COs-x_ms，COs-y_ms，COs-z_msDisplacement of (2);

and S105, representing the rubber shock absorber by the constructed three-dimensional rigidity damping model according to the deviation angle and the definition of each physical parameter, and constructing a six-degree-of-freedom dynamic model of the laser gyro biaxial rotation inertial navigation system, namely as shown in FIG. 4.

s2, respectively obtaining kinetic equations when the inner frame shaft and the outer frame shaft rotate by utilizing a six-degree-of-freedom kinetic model of the laser gyro biaxial rotation inertial navigation system constructed in the step S1, and solving by utilizing a fourth-order Runge-Kutta method to obtain a deviation angle caused by deformation of the rubber shock absorber when the inner frame shaft and the outer frame shaft rotate;

in the actual use process, the rotation mode of the double-shaft rotating mechanism is that the inner frame rotating mechanism and the outer frame rotating mechanism rotate alternately, so that the movement of the inner frame and the outer frame has the following two conditions:

the first condition is as follows: the inner frame shaft rotates, and the outer frame shaft is static;

Case two: the outer frame shaft rotates, and the inner frame shaft is static;

therefore, the deviation angle caused by the deformation of the rubber damper is obtained specifically according to the two rotation conditions of the biaxial rotation mechanism; in particular, the amount of the solvent to be used,

(1) When the rotation condition of the biaxial rotation mechanism is the above-mentioned condition one, that is, when the inner frame shaft rotates and the outer frame shaft does not rotate, the six-degree-of-freedom dynamic model shown in fig. 4 is simplified into a three-degree-of-freedom dynamic model considering only x, y and gamma in a plane perpendicular to the inner frame shaft, as shown in fig. 5;

the dynamic equation of the three-degree-of-freedom dynamic model is as follows:

z＝0；

α＝0；

β＝0；

The rotation angular rates ω of the inner frame axis and the outer frame axis to be determined based on the rotation condition_iAnd ω_osubstituting the dynamic equation into the dynamic equation, solving the dynamic equation by utilizing a fourth-order Runge-Kutta algorithm module ode45 in mathematic calculation software Matlab to obtain deviation angles alpha, beta and gamma generated by the deformation of the rubber shock absorber in the state of the first rotation condition; wherein the deviation angles alpha, beta and gamma are respectively a coordinate system CO-x of the inertial measurement unit_my_mz_mand the virtual inertial measurement unit coordinate system COs-x_msy_msz_msAbout an axis COs-x_ms，COs-y_ms，COs-z_msThe angle of deviation of (c).

(2) when the rotation condition of the dual-axis rotation mechanism is the second condition, that is, the outer frame axis rotates, and the inner frame axis does not rotate, the six-degree-of-freedom dynamic model shown in fig. 4 is simplified into a three-degree-of-freedom dynamic model which only considers x, z and beta in a plane perpendicular to the outer frame axis, as shown in fig. 6;

the three-degree-of-freedom dynamic model has the following dynamic equation:

y＝0；

α＝0；

γ＝0；

The rotation angular rates ω of the inner frame axis and the outer frame axis to be determined based on the second rotation condition_iAnd ω_osubstituting the dynamic equation into the dynamic equation, solving the dynamic equation by utilizing a fourth-order Runge-Kutta algorithm module ode45 in mathematic calculation software Matlab to obtain deviation angles alpha, beta and gamma generated by the deformation of the rubber shock absorber in the state of the second rotation condition; wherein the deviation angles alpha, beta and gamma are respectively a coordinate system CO-x of the inertial measurement unit_my_mz_mAnd the virtual inertial measurement unit coordinate system COs-x_msy_msz_msAbout an axis COs-x_ms，COs-y_ms，COs-z_msthe angle of deviation of (c).

In step S2, the rotation angular rate ω of the inner frame axis and the outer frame axis_iAnd ω_oParticularly, the angular encoders arranged on the inner frame shaft and the outer frame shaft measure in real time to obtain the rotation angular rate omega of the motor of the inner frame shaft_iAnd angular velocity ω of rotation of outer frame axis motor_o；

In the present embodiment, the inner frame shaft motor rotation angular rate ω_iand angular velocity ω of rotation of outer frame axis motor_othe settings were as follows: the first case and the second case are alternately carried out, and one rotation period is 72 s; in a rotation period, 0-18s, the inner frame rotates at a constant speed at an angular rate of 10 DEG/s, and the outer frame is stationary; 18-36s, the inner frame is stationary and the outer frame is rotating at a constant speed at an angular rate of 10 °/s; 36-54s, the inner frame rotates at a constant speed at an angular rate of-10 DEG/s, and the outer frame is stationary; 54-72s, the inner frame is stationary and the outer frame is rotating at a constant speed at an angular rate of-10 °/s;

s3, fitting the corresponding relation between the frame axial angular rate obtained through the dynamic analysis and the deviation angle (alpha, beta, gamma) generated by the deformation of the rubber shock absorber to obtain attitude error compensation information;

Specifically, the specific method for acquiring the attitude error compensation information includes:

(1) When the rotation mode of the biaxial rotation mechanism is the above-described case one, that is, when the inner frame shaft rotates and the outer frame shaft does not rotate, the inner frame shaft rotation angular rate ω_iwith deviation angle γ according to the formula:Fitting to obtain fitting parameters a, b, c and d;

Further, the attitude error compensation information is obtained according to the fitting parameters as follows:

Δα＝0；

in the formula, delta alpha, delta beta and delta gamma are respectively yaw angle error compensation information, pitch angle error compensation information and course angle error compensation information of the biaxial rotation inertial navigation system;

(2) when the rotation mode of the biaxial rotation mechanism is the second case, that is, the outer frame shaft rotates and the inner frame shaft does not rotate, the rotation angular rate to the outer frame shaft is ω_owith deviation angle γ according to the formula:Fitting to obtain fitting parameters e, f, g and h;

further, the attitude error compensation information is obtained according to the fitting parameters as follows:

Δα＝0；

In the formula, Δ α, Δ β, and Δ γ are respectively yaw angle error compensation information, pitch angle error compensation information, and course angle error compensation information of the biaxial rotational inertial navigation system.

in this embodiment, according to the methods in the steps S1 to S3, the obtained specific fitting parameters are: 0.0008 for a, 0.012 for b, 0.002 for c, 0.0004 for d, 0.0007 for e, 0.036 for f, 0.004 for g, and 0.0002 for h.

s4, compensating the attitude output of the laser gyro biaxial rotation inertial navigation system according to the attitude error compensation information;

specifically, the compensated attitude output method is as follows:

s401, acquiring an inertial signal of the navigation resolving plate based on an inertial measurement unit to obtain an attitude output of the inertial navigation system: roll angle theta, pitch angle thetaand a course angle phi;

S402, outputting the attitude (roll angle theta, pitch angle theta) of the inertial navigation system obtained in the step S401and a course angle phi), error compensation information of the roll angle, the pitch angle and the course angle of the biaxial rotational inertial navigation system obtained in the step S3, and an angle encoder arranged on the inner frame shaft and the outer frame shaft to measure in real time to obtain the rotation angular rate omega of the motor of the inner frame shaft_iAnd an outer frameRotation angular rate omega of a shaft motor_osubstituting into the following equation:

θ_c＝θ；

Obtaining the attitude output after real-time compensation, i.e. the roll angle theta_cAngle of pitchand a heading angle phi_c。

fig. 7 shows a process of compensating the attitude output of the laser gyro biaxial rotational inertial navigation system according to the attitude error compensation information.

Because the deformation of the rubber shock absorber does not obviously influence the roll angle error, the method compensates the errors of the pitch angle and the course angle without compensating the roll angle error. This embodiment compares the compensated attitude output obtained by the attitude error compensation method for 288s with the original uncompensated attitude by comparing 4 rotation periods. As shown in FIGS. 8(a) - (c), the roll angle θ between the attitude output compensated by the attitude error compensation method of the present embodiment and the original uncompensated attitude is shown_cAngle of pitchAnd a heading angle phi_cthe specific compensation method is completed by the steps described above. Because the deformation of the rubber shock absorber does not cause obvious influence on the transverse rocking angle error, the method compensates the errors of the longitudinal rocking angle and the course angle except for the compensation of the transverse rocking angle error. This embodiment compares the compensated attitude output obtained by the attitude error compensation method for 4 rotation periods, i.e., 288s, with the original uncompensated attitude. As can be seen from fig. 8(a) to (c), if attitude error compensation is not performed, the laser gyro biaxial rotational inertial navigation system of the present embodimentThe pitch angle output of the system has an approximate rectangular wave error with a peak-to-peak value of 2.4 ', and the course angle output has an approximate rectangular wave error with a peak-to-peak value of 2.0'; after compensation by the compensation method, the peak-to-peak value of the output error of the longitudinal angle is reduced to 0.3 ', the output error of the course angle is reduced to 0.2', and the output accuracy of the compensated longitudinal angle and course angle is improved by about 8 times.

Portions of the invention not disclosed in detail are well within the skill of the art.

although illustrative embodiments of the present invention have been described above to facilitate the understanding of the present invention by those skilled in the art, it should be understood that the present invention is not limited to the scope of the embodiments, and it will be apparent to those skilled in the art that various changes may be made without departing from the spirit and scope of the invention as defined and defined in the appended claims.