Measurement Device and Method for Radial Dynamic Characteristics of Compressed Rubber for Inertial Navigation System

Abstract

The present invention relates to a measuring device and a measuring method for the radial dynamic characteristics of compressed rubber used in an inertial navigation system. The characteristics of the device are as follows: The bolt is inserted into the bolt hole in the center of the base in a manner that the bolt head faces downward. The upper end of the bolt is inserted with a gasket and a connecting nut. The rubber specimen to be measured is inserted onto the bolt through the central hole and is arranged between the upper end of the base and the lower end of the gasket. An actuator plate is inserted into the actuator plate slot arranged on one side of the rubber to be measured and is connected through a fixing pin. On the other side of the rubber to be measured, a lead-out plate is inserted into each of the two lead-out plate slots in the horizontal direction. The measuring block is fixedly clamped between the outer extended ends of the two lead-out plates, and the strain gauge is fixed on the outer vertical surface of the measuring block. The strain gauge is connected to the force sensor through a wire. The present invention realizes the accurate measurement of the radial dynamic characteristics of compressed rubber.

Description

Technical Field

[0001] The present invention belongs to the technical field of hemispherical resonator gyro inertial navigation technology, and in particular relates to a device and method for measuring the radial dynamic characteristics of compressed rubber for an inertial navigation system. Background Art

[0002] During the product design process of a hemispherical resonator gyro inertial navigation system, see Figure 1 , the installation space of its conical frustum is limited, the vertical accuracy requirement is high, and the combined component has high vibration damping characteristics. Therefore, the accurate measurement of the dynamic characteristics (including dynamic stiffness and damping angle) of the compressed rubber 3 used to connect the conical frustum 1 and the system base 2 can improve the dynamic adaptation range of the hemispherical resonator gyro inertial assembly.

[0003] As a typical hyperelastic material, the installation and loading process of rubber is complex. Along with the nonlinearity of the constitutive equation of the rubber elastic material, the broadness of the rubber geometry, the contact of the actual installation state, etc., these nonlinearities seriously affect the accuracy of the hemispherical resonator gyro inertial navigation. Also, since the dynamic characteristics of rubber are mainly determined by the nonlinear viscoelastic mechanical properties of rubber such as the hysteresis effect and strain rate sensitivity, they are easily affected by factors such as the structural size, load, excitation frequency, and excitation amplitude of the compressed rubber. And the quantitative characterization of the dynamic characteristics (dynamic stiffness and damping angle) of the compressed rubber plays an important role in the accuracy compensation of the hemispherical resonator gyro inertial navigation system. Therefore, how to achieve the accurate measurement of the radial dynamic characteristics of the compressed rubber material has become a key problem that urgently needs to be solved in the design process of the hemispherical resonator gyro inertial navigation system. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a device and method for measuring the radial dynamic characteristics of compressed rubber for an inertial navigation system.

[0005] One of the above purposes of the present invention is achieved through the following technical solutions:

[0006] A device for measuring the radial dynamic characteristics of compressed rubber for an inertial navigation system, characterized in that it includes a basic base, bolts, nuts, gaskets, an actuator plate, two lead-out plates, a measuring block, strain gauges, wires, a force sensor, and a rubber specimen to be measured;

[0007] A bolt hole is provided at the center of the basic base, the bolt is inserted into the bolt hole with the bolt head facing downwards, and the upper end of the bolt passes through the gasket and is connected to the nut;

[0008] The rubber specimen to be tested is provided with a central hole, is sleeved on a bolt through the central hole, and is arranged between the upper end of the base and the lower end of the gasket; on one side of the rubber specimen to be tested, a horizontal actuator plate slot is provided, and on the other side of the rubber specimen to be tested, two horizontal guide plate slots are arranged in parallel up and down; at the position corresponding to the actuator plate slot on the rubber specimen to be tested, two vertical pin holes are provided, and at the positions corresponding to the two guide plate slots on the rubber specimen to be tested, two vertical pin holes are communicated and arranged;

[0009] At one end of the actuator plate and one end of the two guide plates, two pin holes are provided; the end of the actuator plate provided with the pin holes is inserted into the actuator plate slot, and is connected with the rubber specimen to be tested through two fixing pins inserted into the corresponding pin holes; the ends of the two guide plates provided with the pin holes are respectively inserted into the upper and lower guide plate slots, and are connected with the rubber specimen to be tested through two fixing pins inserted into the corresponding pin holes;

[0010] The measuring block is fixedly clamped between the outer extending ends of the two guide plates, and the strain gauge is fixed on the outer vertical surface of the measuring block; the strain gauge is connected with the force sensor through a wire.

[0011] The second above-mentioned object of the present invention is achieved through the following technical solution:

[0012] A measuring method for a measuring device for the radial dynamic characteristics of compressed rubber based on the above inertial navigation system, characterized in that it includes the following steps:

[0013] Step 1: According to the geometric dimensions of the actuator plate, the guide plate and the fixing pin, process the rubber specimen to be tested to ensure that the assembled rubber specimen to be tested and the three are in clearance fit;

[0014] Step 2: Perform preloading:

[0015] 2.1 First, assemble the rubber specimen to be tested, the actuator plate, the two guide plates, the fixing pins, the measuring block and the strain gauge to the base through nuts, gaskets and bolts;

[0016] 2.2 Then tighten the nut to apply a certain preload to the rubber specimen to be tested, so that the rubber specimen to be tested and the actuator plate and the two guide plates form a fixed connection through the fixing pins, and this connection state is the initial installation state of the rubber specimen to be tested;

[0017] 2.3 Then measure the height h0 of the base and the rubber specimen to be tested in the initial installation state through an altimeter;

[0018] 2.4 Screw in the nut to deform the rubber specimen to be tested, and measure the height h1 of the compressed rubber specimen to be tested and the base through an altimeter;

[0019] 2.5 Calculate the compression of the rubber specimen to be measured, Δh = h0 - h1;

[0020] Step 3: Apply displacement excitation:

[0021] 3.1 First, connect the outer end of the actuator plate to the actuator end of the vibration test bench, and fix the base on the vibration test bench;

[0022] 3.2 Apply a displacement excitation x(t) = X0sin(ω0t) in the radial direction of the actuator end, where "ω0" is the angular frequency of the excitation and "t" is the excitation time. Record the displacement signal x(t) of the actuator end of the vibration test bench and the force sensor signal F T (t);

[0023] 3.3 Obtain the dynamic stiffness and damping angle of the compressed rubber through geometric construction. Specifically, when the displacement excitation is sinusoidal, its force response is sinusoidal. Plot the displacement on the abscissa and the force on the ordinate to obtain the hysteresis loop of the system. Denote F0 and X0 as the amplitudes of the force and displacement respectively, and U as the area of the hysteresis loop. Then the dynamic stiffness K d and the damping angle δ are calculated by the following formulas

[0024] K d = F0 / X0 (1)

[0025]

[0026] Apply displacement excitations with different frequencies to the actuator end, and obtain the curves of the dynamic stiffness and damping angle of the compressed rubber varying with frequency through calculation.

[0027] Advantages and positive effects of the present invention:

[0028] The present invention realizes the accurate measurement of the radial dynamic characteristics of compressed rubber. Through the construction method, it reveals the evolution law of the radial dynamic characteristics of compressed rubber under different test parameters (depression amount, excitation frequency, and excitation amplitude), and effectively solves the dynamic adaptability requirements of the hemispherical resonator gyro inertial navigation system. This technology is not limited to the accurate measurement of the radial dynamic characteristics of compressed rubber in the resonator inertial navigation system, but can also be extended to rubber components in other strapdown inertial navigation systems. Brief Description of the Drawings

[0029] Figure 1 is a schematic structural diagram of a hemispherical resonator gyro inertial assembly;

[0030] Figure 2 is an overall view of the device for measuring the radial dynamic characteristics of compressed rubber for the inertial navigation system of the present invention;

[0031] Figure 3 is Figure 2Schematic diagram of the appearance without the wires and force sensor;

[0032] Figure 4 It is the displacement excitation and force response diagram of the present invention;

[0033] Figure 5 Schematic diagram of the hysteresis loop of the rubber of the present invention. DETAILED DESCRIPTION

[0034] The structure of the present invention is further described below with reference to the accompanying drawings and by way of examples. It should be noted that the present examples are descriptive rather than restrictive.

[0035] A device for measuring dynamic characteristics of compressed rubber for inertial navigation system, see Figure 2 and Figure 3 It is mainly composed of a basic base 9, bolts 8, nuts 4, gaskets 5, an actuating plate 6, two lead-out plates 10, a measuring block 11, a wire 12, a force sensor 13, and a rubber specimen to be tested 14.

[0036] The basic base is composed of a bottom plate portion, a cylindrical portion arranged at the upper end of the bottom plate portion, and a plurality of triangular rib portions connecting the cylindrical portion and the bottom plate portion, and has good structural stability. A bolt hole is arranged at the center of the basic base, and the bolt hole is a three-order hole structure, the middle hole has the smallest diameter and matches the rod diameter of the bolt, the lower hole has the largest diameter and is used to install the bolt head, and the hole diameter of the upper hole is larger than the rod diameter of the bolt, which facilitates the installation and fixing of the bolt. The bolt is installed in the bolt hole with the bolt head facing downward, and the upper end of the bolt is installed with the gasket and connected to the nut.

[0037] The rubber specimen to be tested is provided with a center hole, through which the bolt is installed, and is arranged between the upper end of the base and the lower end of the gasket. An actuating plate slot along the horizontal direction is provided on one side of the rubber specimen to be tested, and two upper and lower parallel export plate slots along the horizontal direction are provided on the other side of the rubber specimen to be tested. Two vertical pin holes are provided at positions corresponding to the actuating plate slot on the rubber specimen to be tested, and two vertical pin holes are provided at positions corresponding to the two export plate slots on the rubber specimen to be tested.

[0038] Two pin holes are provided at one end of the actuating plate and at one end of the two export plates. One end of the actuating plate with the pin holes is inserted into the actuating plate slot of the rubber specimen to be tested, and is connected to the rubber specimen to be tested through two fixing pins 7 inserted into the corresponding pin holes; one end of the two export plates with the pin holes is respectively inserted into the upper and lower export plate slots, and is connected to the rubber specimen to be tested through two fixing pins inserted into the corresponding pin holes.

[0039] The above nut can achieve the control of different compression amounts of the rubber specimen to be measured. When the rubber specimen to be measured is in the initial installation state of preloading, the actuator plate forms a fixed connection with the rubber specimen to be measured through two fixing pins, and the two lead-out plates also form a fixed connection with the rubber specimen to be measured through two fixing pins.

[0040] The measuring block is fixedly clamped between the outer protruding ends of the two lead-out plates. The measuring block is connected to the force sensor through a wire.

[0041] The measuring method based on the above inertial navigation system for measuring the dynamic characteristics of compressed rubber is as follows, including the following steps:

[0042] Step 1: According to the geometric dimensions of the actuator plate, the lead-out plate, and the fixing pins, process the rubber specimen to be measured to ensure that the assembled rubber specimen to be measured and the three are in clearance fit;

[0043] Step 2: Perform preloading:

[0044] 2.1 First, assemble the rubber specimen to be measured, the actuator plate, the two lead-out plates, the fixing pins, the measuring block, and the strain gauge onto the base through the nut, washer, and bolt;

[0045] 2.2 Then tighten the nut to apply a certain preload to the rubber specimen to be measured. The preload is about 100 N, so that the rubber specimen to be measured forms a fixed connection with the actuator plate and the two lead-out plates through the fixing pins. This connection state is the initial installation state of the rubber specimen to be measured;

[0046] 2.3 Then measure the height h0 of the base and the rubber specimen to be measured in the initial installation state through the altimeter;

[0047] 2.4 Screw in the nut to deform the rubber specimen to be measured, and measure the height h1 of the compressed rubber specimen to be measured and the base through the altimeter;

[0048] 2.5 Calculate the compression amount of the rubber specimen to be measured, Δh = h0 - h1.

[0049] Step 3: Perform displacement excitation:

[0050] 3.1 First, connect the outer end of the actuator plate to the actuator end of the vibration test bench, and fix the base on the vibration test bench;

[0051] 3.2 Apply a displacement excitation x(t) = X0sin(ω0t) in the radial direction of the actuator end, where "ω0" is the angular frequency of the excitation and "t" is the excitation time. Record the displacement signal x(t) of the displacement sensor connected to the actuator plate and the force sensor signal F T (t), as Figure 4 shown;

[0052] 3.3. Obtain the dynamic stiffness and damping angle of the compressed rubber through geometric construction method. Specifically, when the displacement excitation is sinusoidal, its force response is sinusoidal. Plot the displacement on the abscissa and the force on the ordinate, and the hysteresis loop of the system can be obtained as Figure 5 shown. In the figure, "K e " refers to the instantaneous stiffness, that is, the instantaneous tangent of the hysteresis loop. Denote F0 and X0 as the amplitudes of the force and displacement respectively, and U as the area of the hysteresis loop, which is specifically manifested as the area difference swept by the force sensor signal F T (t) within one cycle as Figure 5 shown. Then the dynamic stiffness K d and the damping angle δ are calculated by the following formulas

[0053] K d = F0 / X0 (1)

[0054]

[0055] Apply displacement excitations with different frequencies to the actuator end, and calculate the curves of the dynamic stiffness and damping angle of the compressed rubber varying with frequency.

[0056] Although the embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art can understand that within the spirit scope of the present invention and the appended claims, various substitutions, changes, and modifications are possible. Therefore, the scope of the present invention is not limited to the content disclosed in the embodiments and drawings.

Claims

1. A measuring device for the radial dynamic characteristics of a squeezed rubber for an inertial navigation system, characterized in that: It includes a base pedestal, bolts, nuts, gaskets, a driving plate, two leading plates, measuring blocks, strain gauges, wires, a force sensor, and a rubber specimen to be tested; A bolt hole is provided at the center of the base pedestal. The bolt is inserted into the bolt hole with the bolt head facing downwards. The upper end of the bolt passes through the gasket and is connected to the nut; The rubber specimen to be tested is provided with a central hole and is inserted onto the bolt through the central hole, and is arranged between the upper end of the base pedestal and the lower end of the gasket; On one side of the rubber specimen to be tested, a horizontal driving plate slot is provided, and on the other side of the rubber specimen to be tested, two horizontal leading plate slots are arranged in parallel up and down; At the position corresponding to the driving plate slot on the rubber specimen to be tested, two vertical pin holes are provided, and at the positions corresponding to the two leading plate slots on the rubber specimen to be tested, two vertical pin holes are communicated and provided; One end of the driving plate and one end of the two leading plates are each provided with two pin holes; The end of the driving plate provided with the pin holes is inserted into the driving plate slot and is connected to the rubber specimen to be tested through two fixing pins inserted into the corresponding pin holes; The ends of the two leading plates provided with the pin holes are respectively inserted into the upper and lower leading plate slots and are connected to the rubber specimen to be tested through two fixing pins inserted into the corresponding pin holes; The measuring block is fixedly clamped between the outer extending ends of the two leading plates, and the strain gauge is fixed on the outer vertical surface of the measuring block; The strain gauge is connected to the force sensor through a wire.

2. A measurement method for the radial dynamic characteristics of a squeezed rubber used in the inertial navigation system according to claim 1, characterized in that: It includes the following steps: Step 1: Process the rubber specimen to be tested according to the geometric dimensions of the driving plate, leading plate, and fixing pins to ensure that the assembled rubber specimen to be tested and the three are in clearance fit; Step 2: Conduct preloading: 2.1 First, assemble the rubber specimen to be tested, the driving plate, the two leading plates, the fixing pins, the measuring block, and the strain gauge onto the base pedestal through the nut, gasket, and bolt; 2.2 Then tighten the nut to apply a certain preload to the rubber specimen to be tested, so that the rubber specimen to be tested and the driving plate and the two leading plates form a fixed connection through the fixing pins. This connection state is the initial installation state of the rubber specimen to be tested; 2.3 Then measure the height h0 of the base pedestal and the rubber specimen to be tested in the initial installation state through an altimeter; 2.4 Screw in the nut to deform the rubber specimen to be tested, and measure the height h1 of the compressed rubber specimen to be tested and the base pedestal through an altimeter; 2.5 Calculate the compression amount of the rubber specimen to be tested, Δh = h0 - h1; Step 3: Conduct displacement excitation: 3.1 First, connect the outer end of the driving plate to the driving end of the vibration test bench, and fix the base pedestal on the vibration test bench; 3.

2. Apply a displacement excitation x(t) = X0sin(ω0t) in the radial direction of the actuator end, where "ω0" is the angular frequency of the excitation, "t" is the time of the excitation, and record the displacement signal x(t) of the actuator end of the vibration test bench and the force sensor signal F T (t) connected to the measuring block; 3.

3. Obtain the dynamic stiffness and damping angle of the compressed rubber through geometric construction method. Specifically, when the displacement excitation is sinusoidal, its force response is sinusoidal. Plot the displacement on the abscissa and the force on the ordinate to obtain the hysteresis loop of the system. Denote F0 and X0 as the amplitudes of the force and displacement respectively, and U as the area of the hysteresis loop. Then the dynamic stiffness K d and the damping angle δ are calculated by the following formulas K d = F0 / X0 (1) Apply displacement excitations with different frequencies to the driving end, and calculate the dynamic stiffness and damping angle curves of the compressed rubber varying with frequency.

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