A method of suppressing mechanical vibration noise in an inertial measurement unit output signal

Abstract

The application discloses a method for inhibiting mechanical vibration noise in an output signal of an inertial measurement unit. First, a dynamic coordinate system and a dynamic equation set of the inertial measurement unit are established, then the center of an elastic coordinate system is axially offset relative to the origin of the dynamic coordinate system; in the two axes which do not occur offset, the linear motion of any one axis and the angular motion of the other axis are coupled, thus two motion coupling dynamic equation sets are obtained. The motion coupling dynamic equation sets are transformed to obtain an angular displacement transfer function model of the inertial measurement unit around any one of the two axes which do not occur offset and find the mechanical vibration noise part in the model, finally, a compensation amount corresponding to the mechanical vibration noise part is added in signal processing to offset the mechanical vibration noise part in the output through algorithm. Compared with physical structure inhibition, the application can fundamentally inhibit the mechanical vibration noise existing in the output signal of the inertial measurement unit through algorithm compensation.

Description

Technical Field

[0001] This invention relates to improvements in inertial measurement technology, specifically to a method for suppressing mechanical vibration noise in the output signal of an inertial measurement unit, belonging to the field of inertial measurement technology. Background Technology

[0002] A strapdown inertial measurement unit (SIM) or strapdown inertial navigation system (SINS) is an instrument sensitive to the motion information of a carrier. It typically uses three gyroscopes and three accelerometers orthogonally fixed to the carrier (such as an aircraft, missile, satellite, or vehicle) to measure the carrier's angular velocity and linear acceleration. In practical applications, the SIM must withstand significant shocks and vibrations. Therefore, to ensure reliable and normal operation, vibration dampers are commonly used to protect the SIM. The vibration damper works by elastically storing mechanical energy and dissipating it as heat through damping. Because the damper is elastic, the SIM is not rigidly connected to the carrier. This means that in vibration or shock environments, the SIM output includes noise from the mechanical vibration of the damping system, in addition to the carrier's motion information. Since this noise is not the carrier's actual motion information, suppressing the mechanical vibration noise in the SIM output signal is a crucial issue in SIM development.

[0003] The formation mechanisms of mechanical vibration noise brought about by the vibration reduction system of the inertial measurement unit are mainly divided into the following types: (1) linear-angular motion coupling of the inertial measurement unit; (2) angular-angular motion coupling of the inertial measurement unit; (3) local mechanical vibration of the carrier or the inertial measurement unit. The reasons for motion coupling of the inertial measurement unit in the vibration environment are: (1) the center of mass of the inertial measurement unit does not coincide with the elastic center formed by the vibration damper of the inertial measurement unit; (2) the inertial tensor of the inertial measurement unit has non-zero and non-diagonal elements; (3) the various vibration dampers of the inertial measurement unit have differences in stiffness and damping.

[0004] The vibration reduction system of the inertial measurement unit (IMU) consists of the IMU body, several dampers, and a carrier. The key structural design points for suppressing mechanical vibration noise in the IMU are: (1) Through structural design, the center of mass of the IMU should be made to coincide with the elastic center of the damper to reduce the linear-angular coupling motion of the IMU; (2) The elastic coordinate system should be made to be parallel to the principal axis of inertia of the IMU to reduce the non-zero values ​​of the off-diagonal elements of the inertial tensor, thereby reducing the angular coupling motion of the IMU; (3) The stiffness and damping parameters of each damper of the IMU should be as consistent as possible. Although the above design points provide directions for suppressing mechanical vibration noise from a physical perspective, in actual operation, these design points are difficult to achieve the ideal situation completely. Therefore, the causes of motion coupling still exist to some extent, and the problem of mechanical vibration noise in the output signal of the IMU cannot be fundamentally solved. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the existing technology, the purpose of this invention is to provide a method for suppressing mechanical vibration noise in the output signal of an inertial measurement unit. This invention adds a compensation link and compensation amount in the signal processing, which can fundamentally suppress the mechanical vibration noise in the output signal of the inertial measurement unit.

[0006] The technical solution of this invention is implemented as follows:

[0007] A method for suppressing mechanical vibration noise in the output signal of an inertial measurement unit (IMU) involves a dynamic coordinate system and an elastic coordinate system. The origin of the dynamic coordinate system is located at the center of mass of the IMU body, and its coordinate axes coincide with the principal axes of inertia of the IMU. The origin of the elastic coordinate system is located at the geometric center of all vibration dampers. When there is no motion coupling, the elastic coordinate system coincides with the dynamic coordinate system. The steps are as follows:

[0008] 1) Establish a set of dynamic equations for the inertial measurement unit with six degrees of freedom and no motion coupling; the six degrees of freedom refer to the linear displacement of the inertial measurement unit along the X, Y, and Z axes of the dynamic coordinate system and the angular displacement about the X, Y, and Z axes.

[0009] 2) Let the center of the elastic coordinate system be offset relative to the dynamic coordinate system in one of the three axes of X, Y, and Z, while the dynamic coordinate system is still parallel to the principal axis of inertia of the inertial measurement unit body, and assume that all damper parameters in the vibration reduction system are consistent; at this time, the axial linear motion of any one axis and the axial angular motion of the other axis in the other two axes that have not been offset will be kinematically coupled, resulting in two kinematically coupled dynamic equations.

[0010] 3) Transform the two sets of motion coupling dynamic equations obtained in step 2) to obtain the angular displacement transfer function of the inertial measurement unit rotating around any one of the other two axes that have not shifted.

[0011] 4) Based on the angular displacement transfer function obtained in step 3), identify the part of the expression that belongs to mechanical vibration noise;

[0012] 5) In signal processing, a compensation amount corresponding to the mechanical vibration noise part in the expression is added in a targeted manner. The compensation amount is used by the algorithm to cancel the mechanical vibration noise part in the expression, thereby suppressing the mechanical vibration noise in the output signal of the inertial measurement unit.

[0013] Compared with the prior art, the beneficial effects of the present invention are:

[0014] This invention derives the angular displacement transfer function under coupled conditions from the dynamic equations of motion coupling, and extracts the mechanical vibration noise component from the expression. A targeted compensation step is then added to the signal processing. This compensation step directly cancels out the mechanical vibration noise in the expression through an algorithm, thereby achieving vibration noise suppression. Compared to existing suppression methods that address the physical structure level, this invention can fundamentally suppress the mechanical vibration noise in the output signal of the inertial measurement unit without altering the system structure, making it more adaptable. Attached Figure Description

[0015] Figure 1 The block diagram of the line-angle coupled noise transfer function when the elastic center is offset in the Z-axis;

[0016] Figure 2 A schematic diagram of the arrangement of vibration dampers with the elastic center deviating from the Z-axis;

[0017] Figure 3 This is a schematic diagram of the Y-axis angular velocity response signal of a rigid cuboid under step linear motion obtained from simulation calculations.

[0018] Figure 4 for Figure 1 Block diagram of the line-angle coupling noise transfer function after adding compensation;

[0019] Figure 5 A comparison of the Y-axis angular velocity measurement signal curves under step motion with and without compensation for angular coupling noise.

[0020] Figure 6 The graph shows the Y-axis angular velocity measurement signal curve of a randomly vibrating body with sinusoidal angular motion input and uncompensated linear angular coupling noise.

[0021] Figure 7 The curve of the Y-axis angular velocity measurement signal after compensation for linear angular coupling noise under sinusoidal angular motion input for a randomly vibrating body. Detailed Implementation

[0022] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0023] This method involves a dynamic coordinate system and an elastic coordinate system. The origin of the dynamic coordinate system is located at the center of mass of the inertial measurement unit, and the coordinate axes coincide with the principal axes of inertial measurement unit. The origin of the elastic coordinate system is located at the geometric center of all dampers. When there is no motion coupling, the elastic coordinate system coincides with the dynamic coordinate system.

[0024] 1) Establish a set of dynamic equations for the six degrees of freedom of the inertial measurement unit without motion coupling; the six degrees of freedom refer to the linear displacement of the inertial measurement unit along the X, Y, and Z axes of the dynamic coordinate system and the angular displacement around the X, Y, and Z axes; the origin of the dynamic coordinate system of the vibration reduction system of the inertial measurement unit without motion coupling is located at the center of mass of the inertial measurement unit, and the coordinate axes are parallel to the principal axes of inertia of the inertial measurement unit and coincide with the elastic coordinate system. At this time, the set of dynamic equations for the six degrees of freedom of the model is shown in equation (1). The six equations are independent of each other and can be solved separately to obtain the motion.

[0025] (1)

[0026] In equation (1), m is the mass of the inertial measurement unit, and x, y, and z are the linear displacements of the inertial measurement unit along the X, Y, and Z axes, respectively. , , These represent the linear velocities of the inertial measurement unit along the X, Y, and Z axes, respectively. , , These represent the linear accelerations of the inertial measurement unit along the X, Y, and Z axes, respectively, k. x k y k z These represent the linear motion stiffness of the vibration damping system along the X, Y, and Z axes, respectively, and c x c y c z These represent the linear motion damping of the vibration reduction system along the X, Y, and Z axes, respectively. x u y u z These represent the linear displacements of the carrier along the X, Y, and Z axes, respectively. , , These represent the linear velocities of the carrier along the X, Y, and Z axes, respectively. xx I yy I zz These are the moments of inertia of the inertial measurement unit about the X, Y, and Z axes, respectively. , , These represent the angular displacements of the inertial measurement unit around the X, Y, and Z axes, respectively. , , These represent the angular velocities of the inertial measurement unit around the X, Y, and Z axes, respectively. , , These are the angular accelerations of the inertial measurement unit around the X, Y, and Z axes, respectively; k xx k yy k zz These represent the angular motion stiffness of the vibration reduction system about the X, Y, and Z axes, respectively, c xx c yy c zz These are the angular motion damping of the vibration reduction system about the X, Y, and Z axes, respectively. , , These represent the angular displacements of the carrier about the X, Y, and Z axes, respectively. , , These are the angular velocities of the carrier around the X, Y, and Z axes, respectively.

[0027] 2) In practical engineering, it is difficult to guarantee the absolute coincidence of the center of the elastic coordinate system and the center of mass of the inertial measurement unit, making the motion coupling phenomenon of the inertial measurement unit vibration reduction system unavoidable. Let the center of the elastic coordinate system shift relative to the dynamic coordinate system of the vibration reduction system in one of the X, Y, or Z axes, while the dynamic coordinate system of the vibration reduction system remains parallel to the principal axis of inertia of the inertial measurement unit body, and assume that all damper parameters in the vibration reduction system are consistent. In this case, the axial linear motion of any one of the other two axes that has not shifted and the axial angular motion of the other axis become motionally coupled, resulting in two sets of motion-coupled dynamic equations.

[0028] 3) Transform the two sets of motion coupling dynamic equations obtained in step 2) to obtain the angular displacement transfer function of the inertial measurement unit rotating around any one of the other two axes that have not shifted.

[0029] 4) Based on the angular displacement output transfer function obtained in step 3), identify the part of the expression that belongs to mechanical vibration noise;

[0030] 5) In signal processing, a compensation amount corresponding to the mechanical vibration noise part in the expression is added in a targeted manner. The mechanical vibration noise part in the expression is canceled out by the compensation amount through the algorithm, thereby suppressing the mechanical vibration noise in the output signal of the inertial measurement unit.

[0031] In step 2) of this invention, there are three scenarios where the center of the elastic coordinate system shifts relative to the dynamic coordinate system of the vibration reduction system, namely, shifts along the X, Y, and Z axes. Each shift scenario corresponds to two scenarios in step 3), namely, the inertial measurement unit performs angular motion around the two axes that have not shifted. Each angular motion along an axis is coupled with mechanical vibration noise, so there are a total of 6 scenarios.

[0032] Case 1: Assume that the center of the elastic coordinate system is offset relative to the dynamic coordinate system in the Z-axis, the elastic coordinate system is still parallel to the principal axis of inertia of the cuboid, and assume that all damper parameters are consistent. In step 1), the dynamic equations without motion coupling change due to motion coupling, as shown in equations (2.1) to (2.3).

[0033] (2.1)

[0034] (2.2)

[0035] (2.3)

[0036] In the formula, , , , Let be the linear motion stiffness of the i-th damper along the X-axis and Y-axis, respectively. Let be the Z-axis coordinate value of the i-th vibration damper. The distance of the elastic center offset along the Z-axis;

[0037] By comparing the above equation with equation (1), it can be seen that the formulas for calculating the linear and angular displacements along the Z-axis have not changed and can be solved independently. Equation (2.2) reflects the coupling between the linear motion of the X-axis and the angular motion of the Y-axis.

[0038] Equation (2.2) is transformed by Laplace to obtain equation (3).

[0039] (3)

[0040] Equation (3) is the angular displacement transfer function of the inertial measurement unit around the Y-axis in the X and Y axes where no offset has occurred; where, This belongs to the mechanical vibration and noise part. The angular displacement of the carrier around the Y-axis is useful information. Based on equation (3), a block diagram of the line-angle coupled noise transfer function model can be drawn when the center of the elastic coordinate system shifts along the Z-axis, as shown below. Figure 1 As shown.

[0041] Figure 1 middle, The angular velocity of the carrier around the Y-axis is a physical quantity that the inertial measurement unit needs to measure. The linear acceleration of the carrier along the X-axis, after passing through multiple stages, forms linear-angular coupled mechanical vibration noise, which, along with... After the signals from multiple stages converge, they form the angular velocity of the inertial measurement unit around the Y-axis, which is mixed with linearly coupled mechanical vibration noise. This transfer function model can be modeled and simulated in Matlab Simulink software.

[0042] The following example illustrates how to simulate and suppress mechanical vibration noise. The inertial measurement unit (IMU) body ① is a rigid cuboid, with dimensions of 100mm in length, width, and height, and a mass of 1kg. Four vibration dampers ② are located at the four corner points of the central plane of the cuboid. A dynamic coordinate system OXYZ is established at the center of mass of the IMU body ①. The center of the elastic coordinate system formed by the four vibration dampers ② is offset by z on the Z-axis. c (See Figure 2 The excitation is a linear acceleration along the positive X-axis applied to the mounting base of the inertial measurement unit at time 1 second, with a signal waveform of 10g. The center of the elastic coordinate system is offset from z along the Z-axis. c Simulations were performed for the case of 1mm. The simulation calculations yielded the angular velocity response signal of the rigid cuboid as follows: Figure 3 As shown. From Figure 3 As can be seen, the linear motion excitation of the mounting base of the inertial measurement unit (IMU) causes the IMU to output a step response signal of angular velocity. Since the mounting base of the IMU does not rotate, this step response signal of angular velocity is an erroneous signal caused by linear-angular coupling motion.

[0043] In addition to suppressing angular velocity noise caused by linear-angular coupling by reducing the offset distance between the center of the elastic coordinate system and the center of mass, the compensation step proposed in this invention can be added to the signal processing to suppress mechanical vibration angular velocity noise. The mechanical vibration angular velocity noise signal is... This signal can be reconstructed using the output signal of the X-axis accelerometer, as follows:

[0044] The output of the X-axis accelerometer is After a second integration, the displacement is converted into the X-direction displacement of the inertial measurement unit, which can be derived from the first row of equation (3): Ignoring the second term in the formula, we can derive: The reconstructed mechanical vibration angular velocity noise signal is then:

[0045]

[0046] The reconstructed mechanical vibration angular velocity noise signal is the compensation amount. Subtracting the reconstructed mechanical vibration angular velocity noise signal from the Y-axis gyroscope signal restores the true angular velocity information of the carrier around the Y-axis. Figure 4 The transfer function model incorporates a compensation element to suppress mechanical vibration angular velocity noise. The area within the dashed box is used to reconstruct the mechanical vibration angular velocity noise signal. The Y-axis gyroscope output is designed to eliminate mechanical vibration angular velocity noise.

[0047] After compensation, the influence of linear vibration on the angular velocity output of the inertial measurement unit is greatly suppressed. A noise suppression simulation was performed for the case where the center of mass deviates by 1mm. A comparison of the Y-axis angular velocity measurement signal curves before and after compensation is shown below. Figure 5 .from Figure 5 It can be seen that the angular velocity measurement output of the inertial measurement unit after compensation at time 1s is not affected by the step acceleration.

[0048] A random vibration with an amplitude of 30g was input along the X-axis of the mounting base of the inertial measurement unit (IMU), and a sinusoidal angular velocity signal with an amplitude of 1° / s was input along the Y-axis of the mounting base. The simulation results are shown below. Figure 6 and Figure 7 The compensated Y-axis angular velocity measurement output noise can be seen ( Figure 7 The noise level is significantly lower than that of the uncompensated Y-axis angular velocity measurement output noise. Figure 6 ).

[0049] In scenario two, the center of the elastic coordinate system shifts relative to the dynamic coordinate system along the Z-axis, and equation (2.3) reflects the coupling between the linear motion of the Y-axis and the angular motion of the X-axis. The method for suppressing mechanical vibration noise in the angular displacement output of the inertial measurement unit around the X-axis is as follows. Similar to the compensation approach in scenario one, equation (2.3) is first transformed by Laplace to obtain equation (4).

[0050] (4)

[0051] Equation (4) is the angular displacement transfer function of the inertial measurement unit around the X-axis in the X and Y axes where no offset has occurred; in Equation (4), the part belonging to mechanical vibration noise is .

[0052] Reconstructing mechanical vibration noise, i.e., the compensation amount is ,

[0053] Subtracting the compensation amount from the X-axis gyroscope signal cancels out the mechanical vibration noise component in the expression.

[0054] Case 3: The elastic center is offset along the X-axis, and the mechanical vibration noise in the angular displacement output of the inertial measurement unit around the Y-axis is suppressed as follows. The linear motion of the Z-axis and the angular motion of the Y-axis are coupled, as shown in Equation (5);

[0055] (5)

[0056] In the formula, , Let be the linear motion stiffness of the i-th damper along the Z-axis. Let be the X-axis coordinate value of the i-th vibration damper. The distance of the elastic center offset along the X-axis;

[0057] Equation (5) is transformed by Laplace to obtain equation (6).

[0058] (6)

[0059] Equation (6) is the angular displacement transfer function of the inertial measurement unit around the Y-axis in the Z and Y axes where no offset has occurred; in Equation (6), the part belonging to mechanical vibration noise is Similar to scenario one, reconstructed mechanical vibration noise. Subtracting the compensation amount from the Y-axis gyroscope signal cancels out the mechanical vibration noise part in the expression.

[0060] Case 4: The elastic center is offset along the X-axis, and the mechanical vibration noise in the angular displacement output of the inertial measurement unit around the Z-axis is suppressed as follows. The linear motion of the Y-axis and the angular motion of the Z-axis are coupled, as shown in Equation (7);

[0061] (7)

[0062] In the formula, , Let be the linear motion stiffness of the i-th damper along the Y-axis. Let be the X-axis coordinate value of the i-th vibration damper. The distance of the elastic center offset along the X-axis;

[0063] Equation (7) is transformed by Laplace to obtain equation (8).

[0064] (8)

[0065] Equation (8) is the angular displacement transfer function of the inertial measurement unit around the Z-axis in the Z and Y axes where no offset has occurred; in Equation (8), the part belonging to mechanical vibration noise is Similar to scenario one, reconstructed mechanical vibration noise. Subtracting the compensation amount from the Z-axis gyroscope signal cancels out the mechanical vibration noise part in the expression.

[0066] Case 5: The elastic center shifts along the Y-axis, and the mechanical vibration noise in the angular displacement output of the inertial measurement unit around the X-axis is suppressed as follows. The linear motion of the Z-axis and the angular motion of the X-axis are coupled, as shown in equation (9);

[0067] (9)

[0068] In the formula, , Let be the linear motion stiffness of the i-th damper along the Z-axis. Let be the Y-axis coordinate value of the i-th vibration damper. The distance of the elastic center offset along the Y-axis;

[0069] Equation (9) is transformed by Laplace to obtain equation (10).

[0070] (10)

[0071] Equation (10) is the angular displacement transfer function of the inertial measurement unit around the X-axis in the Z and X axes where no offset has occurred; in Equation (10), the part belonging to mechanical vibration noise is Similar to scenario one, reconstructed mechanical vibration noise. Subtracting the compensation amount from the X-axis gyroscope signal cancels out the mechanical vibration noise part in the expression.

[0072] Case 6: The elastic center shifts along the Y-axis, and the mechanical vibration noise in the angular displacement output of the inertial measurement unit around the Z-axis is suppressed as follows. The linear motion of the X-axis and the angular motion of the Z-axis are coupled, as shown in Equation (11);

[0073] (11)

[0074] In the formula, , Let be the linear motion stiffness of the i-th damper along the X-axis. Let be the Y-axis coordinate value of the i-th vibration damper. The distance of the elastic center offset along the Y-axis;

[0075] Equation (11) is transformed by Laplace to obtain equation (12).

[0076] (12)

[0077] Equation (12) is the angular displacement transfer function of the inertial measurement unit around the Z-axis when no offset occurs in the Z and X axes; in Equation (12), the part belonging to mechanical vibration noise is Similar to scenario one, reconstructed mechanical vibration noise. Subtracting the compensation amount from the Z-axis gyroscope signal cancels out the mechanical vibration noise part in the expression.

[0078] This invention simplifies the strapdown inertial measurement unit (SIM) into a rigid body, spring, and damping vibration reduction system, and establishes a set of dynamic equations and a transfer function model. An excitation signal is input into the transfer function model, and the SIM response output, including mechanical vibration noise, is calculated. A mechanical vibration noise compensation mechanism is constructed, and a noise compensation program is written to suppress mechanical vibration noise.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the applicant has described the present invention in detail with reference to preferred embodiments, those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of the present invention without departing from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A method for suppressing mechanical vibration noise in the output signal of an inertial measurement unit (IMU), comprising a dynamic coordinate system and an elastic coordinate system. The origin of the dynamic coordinate system is located at the centroid of the IMU body, and the coordinate axes coincide with the principal axes of inertia of the IMU. The origin of the elastic coordinate system is located at the geometric center of all vibration dampers. When there is no motion coupling, the elastic coordinate system coincides with the dynamic coordinate system. The method is characterized by: The steps are as follows: 1) Establish a set of dynamic equations for the inertial measurement unit with six degrees of freedom and no motion coupling; the six degrees of freedom refer to the linear displacement of the inertial measurement unit along the X, Y, and Z axes of the dynamic coordinate system and the angular displacement about the X, Y, and Z axes. 2) Let the center of the elastic coordinate system be offset relative to the dynamic coordinate system in one of the three axes of X, Y, and Z, while the dynamic coordinate system is still parallel to the principal axis of inertia of the inertial measurement unit body, and assume that all damper parameters in the vibration reduction system are consistent; at this time, the axial linear motion of any one axis and the axial angular motion of the other axis in the other two axes that have not been offset will be kinematically coupled, resulting in two kinematically coupled dynamic equations. 3) Transform the two sets of motion coupling dynamic equations obtained in step 2) to obtain the angular displacement transfer function of the inertial measurement unit rotating around any one of the other two axes that have not shifted. 4) Based on the angular displacement transfer function obtained in step 3), identify the part of the expression that belongs to mechanical vibration noise; 5) In signal processing, a compensation amount corresponding to the mechanical vibration noise part in the expression is added in a targeted manner. The compensation amount is used by the algorithm to cancel the mechanical vibration noise part in the expression, thereby suppressing the mechanical vibration noise in the output signal of the inertial measurement unit.

2. The method for suppressing mechanical vibration noise in the output signal of an inertial measurement unit according to claim 1, characterized in that: Step 1) The set of uncoupled dynamic equations for the six degrees of freedom of the inertial measurement unit is shown below. （1） In equation (1), m is the mass of the inertial measurement unit, and x, y, and z are the linear displacements of the inertial measurement unit along the X, Y, and Z axes, respectively. , , These represent the linear velocities of the inertial measurement unit along the X, Y, and Z axes, respectively. , , These represent the linear accelerations of the inertial measurement unit along the X, Y, and Z axes, respectively, k. x k y k z These represent the linear motion stiffness of the vibration damping system along the X, Y, and Z axes, respectively, and c x c y c z These represent the linear motion damping of the vibration reduction system along the X, Y, and Z axes, respectively. x u y u z These represent the linear displacements of the carrier along the X, Y, and Z axes, respectively. , , These represent the linear velocities of the carrier along the X, Y, and Z axes, respectively; I xx I yy I zz These are the moments of inertia of the inertial measurement unit about the X, Y, and Z axes, respectively. , , These represent the angular displacements of the inertial measurement unit around the X, Y, and Z axes, respectively. , , These represent the angular velocities of the inertial measurement unit around the X, Y, and Z axes, respectively. , , These are the angular accelerations of the inertial measurement unit around the X, Y, and Z axes, respectively; k xx k yy k zz These represent the angular motion stiffness of the vibration reduction system about the X, Y, and Z axes, respectively, c xx c yy c zz These are the angular motion damping of the vibration reduction system about the X, Y, and Z axes, respectively. , , These represent the angular displacements of the carrier about the X, Y, and Z axes, respectively. , , These are the angular velocities of the carrier around the X, Y, and Z axes, respectively.

3. The method for suppressing mechanical vibration noise in the output signal of an inertial measurement unit according to claim 2, characterized in that: In step 2), the center of the elastic coordinate system shifts relative to the dynamic coordinate system along the Z-axis, and the linear motion of the inertial measurement unit along the X-axis and the angular motion along the Y-axis are coupled. The dynamic equations under motion coupling are shown in equation (2.2). （2.2） In the formula, , Let be the linear motion stiffness of the i-th damper along the X-axis. Let be the Z-axis coordinate value of the i-th vibration damper. The offset distance of the center of the elastic coordinate system along the Z-axis; Equation (2.2) is transformed by Laplace to obtain equation (3): （3） Equation (3) is the angular displacement transfer function of the inertial measurement unit around the Y-axis in the X and Y axes where no offset has occurred; in Equation (3), the part belonging to mechanical vibration noise is ; The compensation amount corresponding to the mechanical vibration and noise part is: Subtracting the compensation amount from the Y-axis gyroscope signal cancels out the mechanical vibration noise component in the expression.

4. The method for suppressing mechanical vibration noise in the output signal of an inertial measurement unit according to claim 2, characterized in that: In step 2), the center of the elastic coordinate system shifts relative to the dynamic coordinate system along the Z-axis, and the linear motion of the inertial measurement unit along the Y-axis and the angular motion along the X-axis are coupled. The dynamic equations under motion coupling are shown in equation (2.3). （2.3） In the formula, , Let be the linear motion stiffness of the i-th damper along the Y-axis. Let be the Z-axis coordinate value of the i-th vibration damper. The distance of the elastic center offset along the Z-axis; Equation (2.3) is transformed by Laplace to obtain equation (4); （4） Equation (4) is the angular displacement transfer function of the inertial measurement unit around the X-axis in the X and Y axes where no offset has occurred; in Equation (4), the part belonging to mechanical vibration noise is ; The compensation amount corresponding to the mechanical vibration and noise part is: ， Subtracting the compensation amount from the X-axis gyroscope signal cancels out the mechanical vibration noise component in the expression.

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