A linear acceleration environment test platform and a test method

Abstract

A linear acceleration environment test platform and a test method, the test platform comprising a platform body, a control system, a guide rail assembly, a device assembly tool, a spring assembly, a spring stretching assembly and a detection unit arranged on the platform body; the device assembly tool is arranged on the guide rail assembly and used for mounting a device under test; the spring assembly comprises a plurality of springs and is symmetrically distributed on both sides of the guide rail assembly; the spring stretching assembly is used for stretching the spring assembly to a predetermined stretching position; the device assembly tool abuts against the spring stretching assembly, and the device assembly tool is driven to move linearly by releasing the spring stretching assembly. The application also comprises a test method of the linear acceleration environment test platform. The application has simple structure, low manufacturing cost, can effectively simulate the real dynamic response of the device under test under the action of linear acceleration, finely evaluate the independent performance of the device under test, and is particularly suitable for batch test requirements of inertial navigation devices, low-cost aircrafts and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of simulation test technology, in particular to a linear acceleration environment test platform and a test method. BACKGROUND

[0002] With the continuous development of aircraft technology, many new low-cost aircraft and supporting equipment have emerged. In the development process of these new aircraft, the performance and precision of the inertial navigation device or the aircraft under overload environment must be measured and verified. Currently, the common methods for simulating overload environment mainly include centrifuge test, rocket sled test and whole machine flight test.

[0003] (1) Centrifuge test

[0004] Centrifuge overload test is a ground test method for simulating the product to withstand sustained radial acceleration by high-speed rotation to generate controllable centrifugal force. However, centrifuge is mainly used to simulate radial acceleration, while the overload of aircraft and supporting equipment in actual flight is mainly linear acceleration. Therefore, centrifuge cannot effectively simulate the real dynamic response of aircraft under linear acceleration, especially cannot accurately evaluate the navigation and positioning precision of the measured equipment under this condition.

[0005] (2) Rocket sled test

[0006] Rocket sled overload test is a test method for verifying the performance of aircraft by simulating the high overload flight environment of aircraft through ground facilities. Its working principle is: taking the boost engine carried by the rocket sled itself and the tested engine as the power source, driving the rocket sled system to realize high-speed movement on the special slide rail, thereby simulating the flight movement environment of the aircraft, completing the performance test and data acquisition of the aircraft under high acceleration condition. This test can drive the sled to slide at high speed on a long track (such as a 9km track) through the rocket engine, accurately simulate the high acceleration, strong vibration and aerodynamic heat coupling environment of the aircraft in the flight process, and provide basis for evaluating the navigation precision, signal stability and other core indicators of the aircraft under dynamic overload.

[0007] However, the rocket sled overload test has significant cost and facility threshold problems: a few kilometers of precise tracks and supporting deceleration systems (such as water tank deceleration devices) need to be built, and the cost of rocket fuel consumption, test control equipment loss and post-maintenance of a single test is high. Therefore, this method is difficult to meet the batch demand of current low-cost aircraft for overload test.

[0008] (3) Whole machine flight test

[0009] Whole machine flight test tests the comprehensive performance of the aircraft through physical flight test, and can obtain measured data in a real flight environment. However, this test method has significant limitations: on the one hand, the whole machine flight test has high cost and high complexity of organization, and is restricted by environmental factors such as weather and airspace, and has poor test repeatability, which is difficult to meet the batch test demand of low-cost aircraft whole machine; on the other hand, in the linear acceleration test scene, the real-time accuracy and overload state of the aircraft are affected by the coupling of multiple systems, and it is difficult to finely evaluate the independent performance thereof, and if a fault occurs during flight, it is difficult to accurately locate the fault source due to the complex whole machine environment, and the fault source cannot be debugged and verified independently.

[0010] Therefore, in view of the development demand of low-cost aircraft whole machine or inertial navigation device, the present application urgently needs to design a linear acceleration environment test platform which is simple to operate, convenient to use and low in cost, so as to make up for the shortcomings of the existing method in economy, applicability and batch test capability. SUMMARY

[0011] The purpose of the present application is to overcome the above-mentioned shortcomings of the prior art and provide a linear acceleration environment test platform and test method which are simple in structure, low in manufacturing cost and high in measurement accuracy.

[0012] The technical scheme of the present application is:

[0013] The linear acceleration environment test platform of the present application comprises:

[0014] A platform body;

[0015] A guide rail assembly comprising a linear guide rail laid on the platform body;

[0016] A spring assembly comprising a plurality of springs symmetrically distributed on both sides of the linear guide rail; and one end of each spring is a fixed end, and the other end is a stretchable end which can be released;

[0017] A spring stretching assembly comprising a fixed part, a movable part and a movable part fixing tool; the fixed part is connected with the fixed end of each spring; the movable part is slidingly connected to the linear guide rail and connected with the stretchable end of each spring, and is used for stretching the stretchable end of the spring assembly to a predetermined stretching position, and fixing or releasing the movable part through the movable part fixing tool;

[0018] A device assembly tool slidingly connected to the linear guide rail, and a device to be tested is mounted thereon; and when the stretchable end of the spring assembly is stretched to the predetermined stretching position, the device assembly tool abuts against the movable part of the spring stretching assembly, so that the movable part is released, and the restoring force of the spring assembly drives the device assembly tool to move linearly along the linear guide rail;

[0019] The detection unit comprises an inertial measurement module mounted on the equipment assembly tooling for detecting real-time acceleration and angular velocity of the equipment under test.

[0020] The control system is used for acquiring first acceleration information measured by the inertial measurement module and second acceleration information read by the equipment under test itself, comparing and analyzing the first acceleration information with the second acceleration information, and acquiring a comparison and analysis result.

[0021] Further, the fixed part comprises two groups of fixed seats symmetrically arranged on the two sides of the linear guide rail, the fixed seat comprises a vertical plate connected with the platform body, and a horizontal plate horizontally extending outward from the vertical plate, and the horizontal plate is connected with the fixed end of the spring.

[0022] Further, the movable part comprises a movable seat slidably connected to the linear guide rail and an adapter seat symmetrically connected to the two sides of the movable seat; the side of the movable seat facing the equipment assembly tooling is a plane as an abutting surface in contact with the equipment assembly tooling; and the adapter seat is connected with the stretched end of the spring.

[0023] Further, the movable part fixing tooling is arranged on the linear guide rail and comprises a first horizontal plane, a vertical plane and a second horizontal plane; a notch is arranged between the first horizontal plane and the vertical plane, the shape of the notch matches the part protruding from the upper surface of the linear guide rail on the movable seat, and the notch can limit the transverse displacement of the movable seat; the first horizontal plane is provided with a fixing member for fixing or releasing the movable part, and the fixing member is connected with the movable seat of the movable part; and the second horizontal plane is detachably connected with the platform body.

[0024] Further, the bottom surface of the linear guide rail is fixed with a buffer part, and the buffer part is arranged at the terminal position of the movable part of the spring stretching assembly; the buffer part comprises a buffer connecting plate connected with the linear guide rail and a first buffer layer extending downward from the buffer connecting plate; the movable part is connected with a second buffer layer, and the second buffer layer is configured to finally impact on the first buffer layer after the movable part is released.

[0025] Further, the detection unit further comprises a linear grating ruler installed on the moving path of the equipment under test and parallel to the linear guide rail, and a reading head of the linear grating ruler is arranged on the equipment assembly tooling for measuring the relative position of the equipment under test in the linear direction, so as to compare and verify the self-position data read in the equipment under test.

[0026] The test method of the linear acceleration environment test platform according to the foregoing linear acceleration environment test platform comprises the following steps:

[0027] S1: install the device under test and the inertial measurement module on a device assembly tool, and slidably install the device assembly tool on a linear guide rail;

[0028] S2: calculate and obtain a predetermined stretching position of the spring assembly according to a spring theoretical model, stretch the spring assembly to the predetermined stretching position through the movable part of the spring stretching assembly, and fix the spring assembly through the movable part fixing tool;

[0029] S3: move the device assembly tool to the position of the movable part of the spring stretching assembly and abut against it, then release the movable part, so that the restoring force of the spring assembly drives the device assembly tool to do linear acceleration motion along the linear guide rail;

[0030] S4: during the acceleration motion, synchronously obtain the first acceleration information measured by the inertial measurement module and the second acceleration information read by the device under test itself, compare and analyze the first acceleration information and the second acceleration information, and verify the accuracy of the acceleration data obtained by the inertial measurement module based on the comparison and analysis result.

[0031] Further, the establishment and compensation method of the spring theoretical model comprises:

[0032] a. obtain the initial deformation amount of each spring in the spring assembly;

[0033] b. based on the initial deformation amount, obtain the total deformation amount of each spring in the spring assembly after the displacement of one end of the spring assembly;

[0034] c. based on the total deformation amount, calculate the spring force of a single spring according to Hooke's law, and obtain the sum of the spring forces of each spring in the spring assembly at the initial position as the initial spring total force;

[0035] d. according to the total deformation amount, the spring force of a single spring and the initial spring total force, calculate the sum of the spring forces of each spring in the spring assembly after displacement as the displacement spring total force, and obtain the relationship model between the displacement spring total force and the overall displacement amount of the spring assembly;

[0036] e. take the multiple sets of overall displacement amount of the spring assembly and the corresponding displacement spring total force data obtained by executing steps b to d multiple times as a training set, and solve the error compensation model representing the relationship between the displacement spring total force and the overall displacement amount through a regression fitting algorithm;

[0037] f. Using the test data not involved in step e modeling as a validation set, the prediction performance of the error compensation model is tested; the validation process includes: according to the spring theory model, the spring assembly is stretched to a predetermined position, the actual spring total force at the predetermined position is collected, and the accuracy and reliability of the error compensation model are quantitatively evaluated by calculating the error between the actual spring total force and the spring total force predicted by the error compensation model according to the predetermined position;

[0038] g. If the verification result of step f meets the requirements, the error compensation model is applied to the control system for obtaining the overall stretching displacement of the spring assembly according to the target spring total force, and the predetermined stretching position is obtained.

[0039] Further, the calculation formula of steps a-d includes:

[0040] 1) Initial deformation x 0i Obtained by the following formula:

[0041] x 0i =L-L 0i

[0042] In the formula, L is the initial length of the spring, L 0i is the natural length of the i-th spring; if x 0i > 0, it means that the spring is initially in a stretched state with an initial tension; if x 0i < 0, it means that the initial state is compression;

[0043] 2) Total deformation of the spring x i Obtained by the following formula:

[0044] x i =(L+Δ)-L 0i =(L-L 0i )+Δ=x 0i +Δ

[0045] In the formula, Δ is the displacement generated when the spring moves;

[0046] 3) The spring force F of a single spring i Obtained by the following formula:

[0047] F i =k i ×x i

[0048] In the formula, F i is the spring force of the i-th spring, and k i is the stiffness coefficient of the i-th spring;

[0049] 4) The initial spring total force F0 is obtained by the following formula:

[0050] F0=ΣF i0

[0051] F i0 =k i ×x 0i

[0052] Wherein, F0 is the sum of the spring force of all springs in initial position; x 0i is the initial deformation of the i-th spring, and x 0i =L-L 0i , F i0 is the spring force of the i-th spring in initial position;

[0053] 5) The total spring force F after displacement is obtained by the following formula:

[0054] F=ΣF i

[0055] The above formula is integrated to obtain:

[0056] F=F0+(Σk i )×Δ

[0057] 6) The relationship model between the total spring force F after displacement and the displacement Δ is established:

[0058] Let Σk i be the equivalent stiffness coefficient K=Σk i , and F=F0+K×Δ.

[0059] In the formula, K is the sum of the stiffness coefficients of all springs.

[0060] The beneficial effects of the present application are:

[0061] (1) The test platform is based on a spring assembly, a guide rail assembly and a spring stretching assembly, has simple overall structure, low manufacturing cost, is easy to maintain, has low failure rate, is not restricted by environmental factors, and is particularly suitable for batch testing requirements of inertial navigation devices, low-cost aircrafts and the like;

[0062] (2) By arranging the spring assembly and the spring stretching assembly, the equipment assembly tool is driven by the restoring force of the spring assembly to move linearly along the linear guide rail at linear acceleration, on the one hand, compared with the active driving source such as a motor and a cylinder, the spring release process is purely mechanical power, does not produce any electromagnetic interference or hydraulic / pneumatic noise, which is crucial for testing the inertial navigation device extremely sensitive to the electromagnetic environment, ensures the authenticity of the test results, and avoids the measurement error introduced by the driving device itself; on the other hand, the real dynamic response of the measured equipment under the action of linear acceleration can be effectively simulated, and the independent performance of the measured equipment can be finely evaluated;

[0063] (3) By modeling and optimizing the spring assembly, the tension generated by the spring assembly as a whole can be balanced relative to the linear guide rail to avoid excessive friction on the slider caused by lateral torque or the device under test being pulled out of the linear guide rail, etc., thus providing an undisturbed linear dynamics environment for the device under test, ensuring high fidelity of the test environment and eliminating errors introduced by the system itself;

[0064] (4) By setting the buffer part, the spring tension assembly can be prevented from being damaged due to overload, greatly improving its service life. BRIEF DESCRIPTION OF DRAWINGS

[0065] Figure 1 is a structure diagram of the embodiment of the application for fixing the movable part by the movable part fixing tool (the spring assembly is not shown);

[0066] Figure 2 is a structure diagram of the embodiment of the application for separating the movable part from the movable part fixing tool.

[0067] BRIEF DESCRIPTION OF DRAWINGS

[0068] 1, platform body; 2, guide rail assembly; 3, device assembly tool; 4, spring assembly; 5, spring tension assembly; 6, device under test; 7, inertial measurement module; 8, linear grating ruler; 9, buffer part;

[0069] 21, linear guide rail; 22, first slider; 41, spring; 51, fixed part; 52, movable part; 53, second slider; 54, movable part fixing tool; 61, clamp; 81, reading head; 91, buffer connecting plate; 92, first buffer layer;

[0070] 521, movable seat; 522, adapter seat; 523, second buffer layer; 541, pull ring type indexing pin. DETAILED DESCRIPTION

[0071] The application will be further described in detail below in combination with the drawings and specific embodiments.

[0072] As Figure 1 and Figure 2The linear acceleration environment test platform comprises a platform body 1, a control system, a guide rail assembly 2, a device assembly tool 3, a spring assembly 4, a spring stretching assembly 5 and a detection unit arranged on the platform body 1. The guide rail assembly 2 is arranged on the platform body 1, and the device assembly tool 3 is arranged on the guide rail assembly 2 and used for mounting a device under test 6. The spring assembly 4 comprises a plurality of springs 41, each of which is mounted on the spring stretching assembly 5 and symmetrically distributed on both sides of the guide rail assembly 2. The spring stretching assembly 5 is used for stretching the spring assembly 4 as a whole to a predetermined stretching position. The device assembly tool 3 abuts against the spring stretching assembly 5, and the device assembly tool 3 and the device under test 6 assembled thereon are driven to move linearly by releasing the spring stretching assembly 5. The detection unit is used for detecting the real-time acceleration, angular velocity and real-time position of the device under test 6 in the linear direction. The control system is used for acquiring the acceleration data and position data measured by the detection unit and the acceleration data and position data read by the device under test, and performing comparison and analysis on the data one by one to obtain comparison and analysis results, so as to verify the accuracy of the acceleration data and position data obtained by the detection unit based on the comparison and analysis results.

[0073] In the embodiment, the guide rail assembly 2 is used to provide a test infrastructure for the test platform, and comprises a linear guide rail 21 arranged on the platform body 1 and a first sliding block 22 slidably connected to the linear guide rail. The linear guide rail 21 can be a single rail or a double rail, which can be selected according to the mass and size of the device under test 6. In the embodiment, the linear guide rail 21 is preferably designed as a double rail. The first sliding block 22 is connected to the device assembly tool 3, i.e. arranged at the bottom of the device assembly tool 3, and is used to bear the device assembly tool 3 and the device under test 6 thereon and ensure that the load is distributed in a predetermined manner. Preferably, the device assembly tool 3 and the first sliding block 22 are detachably connected, such as by screwing or clamping, so as to replace the matched device assembly tool for different devices under test.

[0074] In the embodiment, the spring stretching assembly 5 comprises a fixed part 51, a movable part 52, a second sliding block 53 and a movable part fixing tool 54. The second sliding block 53 is slidably connected to the linear guide rail 21, and the movable part 52 is mounted on the second sliding block 53 and can move along the second sliding block 53 on the linear guide rail 21. The movable part fixing tool 54 is used to fix the movable part 52 at a predetermined stretching position when the movable part 52 drives the spring assembly 4 to move to the position. The fixed part 51 and the movable part 52 are mounted on the platform body 1 and distributed on both sides of the device assembly tool 3. One end of each spring 41 of the spring assembly is connected to the fixed part 51 as a fixed end, and the other end is connected to the movable part 52 as a stretching end.

[0075] Preferably, the fixed part 51 comprises two groups of fixed seats, which are symmetrically arranged on the two sides of the linear guide rail 21, and the fixed seats are designed as L-shaped structures, the vertical plates of which are bolted to the platform body 1, and the horizontal plates extend away from the linear guide rail 21, and are used for connecting the fixed ends of the plurality of springs 41. For example, a plurality of connecting holes are arranged on the horizontal plates, and the ends of the springs 41 are provided with hooks, which can be hooked on the connecting holes for fixation.

[0076] Preferably, the movable part 52 comprises a movable seat 521 connected to the second sliding block 53, and adapter seats 522 symmetrically connected to the two sides of the movable seat 521, wherein the surface of the movable seat 521 facing the equipment assembly tool 3 is a plane, so as to abut against the equipment assembly tool 3; the adapter seats 522 can be designed as the same structure as the fixed seats, and are used for connecting the stretched ends of the springs 41, which will not be described in detail here.

[0077] Preferably, the movable part fixing tool 54 is arranged on the linear guide rail 21, and is designed as a Z-shaped structure, comprising a first horizontal surface, a vertical surface and a second horizontal surface; wherein the gap formed by the first horizontal surface and the vertical surface matches the part of the movable seat 521 protruding from the upper surface of the linear guide rail 21, and can limit the lateral displacement of the movable seat 521. The second horizontal surface is in contact with the linear guide rail 21 and is detachably connected with the platform body 1. For example, at least two positioning pins are arranged at the middle position of the bottom surface of the second horizontal surface, and a plurality of positioning holes are arranged on the platform body 1 in the movable path of the movable part fixing tool 54, when the movable part fixing tool 54 needs to be fixed at the target position, the positioning pins can be positioned into the positioning holes of the platform body 1 through the gap between the two linear guide rails 21. In addition, in order to fix the movable part 52, a pull ring type indexing pin 541 is arranged on the first horizontal surface of the movable part fixing tool 54, and a pin hole matched with the pull ring type indexing pin 541 is arranged on the movable seat 521 of the movable part, and the movable part 52 can be fixed by clamping the gap of the movable part fixing tool 54 on the movable seat 521 and rotating the pull ring type indexing pin 541 into the pin hole.

[0078] In the embodiment, the spring assembly 4 is used to provide power for the test platform, comprising a plurality of springs 41, and the number of the springs 41 is determined according to the mass of the measured equipment 6 in the test platform and the required test overload value (unit: g). Preferably, the plurality of springs 41 are divided into two groups with the same number, and are connected between the fixed part 51 and the movable part 52 of the spring stretching assembly, and are symmetrically distributed along the linear guide rail 21. For example, four springs 41 are arranged on the two sides of the linear guide rail 21 respectively, and the pulling forces generated by the springs are balanced with respect to the linear guide rail 21, so as to avoid the situations that the lateral moment causes the friction force on the sliding block to be too large or the measured equipment to be pulled out of the linear guide rail, and thus causes the test to fail.

[0079] In the embodiment, the detection unit includes a high-precision inertial measurement module 7 and a linear grating ruler 8. The inertial measurement module 7 is mounted on the equipment assembly tool 3. Since the equipment assembly tool 3 simultaneously assembles the measured equipment 6 and the inertial measurement module 7, the equipment assembly tool 3 is preferably designed in a Z-shaped structure, including a first horizontal mounting plate, a first vertical plate and a second horizontal mounting plate. The first horizontal mounting plate is connected to the first sliding block 22, and a groove, such as an arc-shaped groove, for placing the measured equipment 6 can be arranged on the first horizontal mounting plate. The second horizontal mounting plate is used for mounting the inertial measurement module 7, which is used to detect the real-time acceleration and angular velocity of the measured equipment 6 in three directions (X, Y and Z axes). In addition, the linear grating ruler 8 is mounted on the platform body 1, located between the two linear guide rails 21 and parallel to the linear guide rails 21, and the mounting position is located on the movement path of the measured equipment 6. The reading head 81 of the linear grating ruler 8 is mounted on the equipment assembly tool 3, for example, mounted on one side of the inertial measurement module 7, which is used to cooperate with the linear grating ruler 8 to measure the relative position of the measured equipment 6 in the linear direction, so as to verify the accuracy of the self-position data of the measured equipment read by the satellite navigation.

[0080] In the embodiment, the bottom surface of the linear guide rail 21 is fixed with a buffer part 9, and the buffer part 9 is arranged at the end position of the movable part 52 of the spring stretching assembly. The buffer part 9 includes a buffer connecting plate 91 connected with the linear guide rail and a first buffer layer 92 extending downward from the buffer connecting plate 91, and the buffer surface of the first buffer layer 92 is arranged towards the movable part 52. The movable seat 521 of the movable part is connected with a second buffer layer 523 on the side towards the first buffer layer 92. Preferably, each buffer layer is a foam plate, so that the second buffer layer 523 of the released movable part can impact on the first buffer layer 92, for protecting the spring stretching assembly 5 from being damaged due to overload.

[0081] In the embodiment, since multiple springs 41 are used in the test platform, there are differences between different springs in the initial position (different initial lengths and different spring rigidities), so it is necessary to detect and confirm the correlation between the displacement and the tension of each spring 41, so as to ensure that the tension generated by the entire spring assembly 4 is balanced with respect to the linear guide rail 21, and the overall tension can be obtained according to the stretching length, so as to meet the requirements of the overload test. It can be said that due to the different tightness of the springs in the initial position, the springs may be in a stretched, compressed or natural length state, and each spring has an initial deformation, so the tension generated by each spring is different when the same length is stretched, and the total thrust generated by the entire spring assembly 4 and the displacement is generally in a linear relationship, and the linear relationship is related to the stiffness coefficient k, the natural length L0, the initial length L, the spring assembly displacement x (i.e. the overall displacement of the spring assembly) and the like of each spring, so the following theoretical model of the spring is built in the embodiment:

[0082] 1. Initial deformation: This refers to the deformation of the spring in its initial position, which is obtained using the following formula:

[0083] x 0i =LL 0i (1)

[0084] In the formula, L is the distance between the two ends of the spring in its initial state, that is, the initial length. 0i Let x be the natural length of the i-th spring. 0i If x > 0, it means the spring is initially in a stretched state with initial tension; if x 0i If the value is less than 0, it indicates that the initial state is compressed.

[0085] 2. Total deformation of a spring: This refers to the difference between the distance between the two ends of the spring when one end is pulled and the spring's natural length. It is obtained using the following formula:

[0086] x i =(L+Δ)-L 0i =(LL 0i )+Δ=x 0i +Δ (2)

[0087] In the formula, x i Let L be the total deformation and Δ be the displacement generated when the spring moves. Then the distance between the springs becomes L+Δ.

[0088] 3. The elastic force of a single spring: The elastic force of each spring is related to the spring constant, according to Hooke's Law, that is:

[0089] F i =k i ×x i (3)

[0090] In the formula, F i Let k be the elastic force of the i-th spring. i Let be the spring constant of the i-th spring.

[0091] It is understandable that, regarding the direction of the elastic force, when the spring is stretched (x... i When the spring force is greater than 0, it acts as a tension force, attempting to compress the spring; when the spring is compressed (x... i When <0), the elastic force manifests as a pushing force, attempting to stretch the spring.

[0092] 4. Initial total spring force: This refers to the sum of the elastic forces of all springs at the initial position, i.e.:

[0093] F0=ΣF i0 (4)

[0094] F i0 =k i ×x 0i(5)

[0095] In the formula, F0 is the sum of the elastic forces of all springs at their initial positions, which is also the total initial spring force; x 0i Let x be the initial deformation of the i-th spring. 0i =LL 0i F i0 Let be the spring force at the initial position of the i-th spring.

[0096] 5. Total spring force after displacement: This refers to the total elastic force of the spring assembly after one end is pulled and a certain displacement is achieved, i.e.:

[0097] F=ΣF i (6)

[0098] In the formula, F is the total force of the springs, which is the sum of the spring forces of all the springs.

[0099] 6. Combining formulas (1) to (6), we can obtain:

[0100] F=F0+(Σk i )×Δ (7)

[0101] 7. Establish a model relating the total spring force F to the displacement Δ after displacement:

[0102] Let Σk i The equivalent stiffness coefficient K = Σk i Therefore, the relationship between the total spring force F and the displacement Δ after displacement is:

[0103] F = F0 + K × Δ (8)

[0104] In the formula, F0 is the sum of the elastic forces at the initial positions of all springs (the elastic force when Δ=0), and K is the sum of the spring constants of all springs.

[0105] It can be said that the dynamic-displacement relationship of a spring assembly can be described by a theoretical model within the elastic limit. However, in real-world environments, due to nonlinear factors such as gaps and friction in the spring assembly, the theoretical model may contain deviations. This embodiment establishes an error compensation model through sample training to determine the relationship between input and output. Specifically:

[0106] For each data point, the error e is defined as the deviation between the actual value and the theoretical value. The error e has a linear relationship with the displacement x, which is suitable for scenarios where systematic errors are the main type and the patterns are simple.

[0107]

[0108] In the formula, x is the displacement of the spring assembly. It is an error term that follows a standard normal distribution with a mean of 0; β 0、 β1 is a regression coefficient;

[0109] The error compensation model formula of the power-displacement relationship of the spring assembly is:

[0110]

[0111] In the formula, is the total force of the spring fitted, F 0 is the initial total force of the spring, x is the displacement of the spring assembly, and K is the sum of the stiffness coefficients of all springs.

[0112] For and x1, x2,..., x k At the same time, n groups of observation values (x t ) are observed independently for n times, and error terms , t = 1, 2,..., n (n > k + 1) are calculated, which satisfy the relationship:

[0113]

[0114] Take the straight line with the smallest total gap between the model prediction result and the true result as the final straight line, define the loss function as the mean square error, and the target is , the mean square error is expressed as:

[0115]

[0116] To obtain the optimal parameters, the mean square error is minimized, the derivative of the mean square error is taken, and the coefficient is taken when the derivative is zero. The derivative of the mean square error is as follows:

[0117]

[0118] The actual total force of the spring and the displacement data of the spring assembly collected by multiple tests are taken as the training set for linear regression fitting, and the error compensation model of the relationship between the total force F of the spring and the displacement x of the spring assembly is solved. The prediction performance of the error compensation model is verified by using "test data not involved in modeling" (10%-20% of the samples are reserved as the verification set). During verification, the spring assembly is stretched to the predetermined position according to the theoretical model of the spring, and the actual total force of the spring at that position is collected. The accuracy and reliability of the error compensation model are quantitatively evaluated by calculating the error between the actual force and the predicted force of the error compensation model.

[0119] If the verification result meets the requirements, the error compensation model is applied to the control system to obtain the overall stretching displacement of the spring assembly according to the target total force of the spring, and the predetermined stretching position is obtained.

[0120] The test method of the embodiment specifically includes the following steps:

[0121] S101: The device under test 6 and the inertial measurement module 7 are fixed to the device assembly tool 3, and the device assembly tool 3 is slidably installed on the linear guide rail 21.

[0122] Specifically, the device under test 6 is fastened to the groove of the device assembly tool 3 by the clamp 61. The device under test 6 can be, but is not limited to, a complete inertial navigation device, a separate acceleration sensor assembly, or a low-cost aircraft whole machine, and the device under test has acceleration data reading and positioning navigation functions.

[0123] S102: The predetermined stretching position of the spring assembly 4 is calculated and obtained according to the theoretical model of the spring, the spring assembly 4 is stretched to the predetermined stretching position by the movable part 52 of the spring stretching assembly, and is fixed by the movable part fixing tool 54.

[0124] Specifically, in order to make the device assembly tool move linearly at a high speed, one end of the spring assembly 4 is fixed by the fixed part 51 of the spring stretching assembly 5, and the other end is connected to the movable part 52; the spring assembly 4 is stretched to the predetermined stretching position along the linear guide rail by the movable seat fixed on the second slider of the linear guide rail, and the movable seat 521 is fixed by the movable part fixing tool 54.

[0125] S103: The device assembly tool 3 is moved to the position of the movable part of the spring stretching assembly along the first slider 22 and is in abutment with the movable part, and then the movable part 52 is released, so that the restoring force of the spring assembly 4 drives the device assembly tool 3 to move linearly at a high speed along the linear guide rail.

[0126] Specifically, when the test is performed, the device assembly tool 3 is in contact with the movable seat 521, the tension of the spring assembly 4 can be converted into the acceleration of the device assembly tool 3 through the contact between the two, and then the pull ring type indexing pin 541 of the movable part fixing tool 54 is rotated out, the movable part 52 is released, so that the movable part 52 pushes the device assembly tool 3 to move linearly at a high speed along the linear guide rail 21 under the restoring force of the spring assembly 4.

[0127] S104: During the acceleration process, the first acceleration information measured by the inertial measurement module 7 and the second acceleration information read by the device under test itself are synchronously obtained, the first acceleration information and the second acceleration information are compared and analyzed, and based on the comparison and analysis result, the accuracy of the acceleration data obtained by the inertial measurement module 7 is verified.

[0128] Specifically, the movable part 52 of the spring tension assembly can move along the linear guide rail 21 with the equipment assembly tool 3 and the measured equipment 6 assembled thereon at a linear acceleration, while the high-precision inertial measurement module 7 synchronously obtains acceleration data of the test process. The detection data of the inertial measurement module 7 and the data read from the measured equipment 6 are compared by a collection system (such as an upper computer, a computer or a controller) to ensure the accuracy of the acceleration data obtained by the inertial measurement module 7. For example, the acceleration data read by the measured equipment 6 itself is taken as a reference to verify the accuracy of the data obtained by the external inertial measurement module (IMU). The purpose of the verification is to evaluate the performance of the IMU and provide a basis for subsequent data use or error compensation. After the verification is passed, the IMU data can be accepted by the system; if not, the equipment needs to be replaced or calibrated according to the error analysis results.

[0129] At the same time, the linear grating ruler 8 and the reading head 81 cooperate to obtain the relative position of the measured equipment 6 to verify the accuracy of the position data of the satellite navigation read by the measured equipment.

[0130] Since the bottom surface of the linear guide rail 21 is provided with a buffer part 9 at the terminal position of the movement of the movable part 52, when the second buffer layer 523 on the movable part collides with the first buffer layer 92, the spring tension assembly can be protected to avoid damage due to overload.

[0131] In addition, the term "connection" should be understood broadly, for example, it can include fixed connection, detachable connection or integral connection; it can include direct connection or indirect connection through an intermediate medium, and it can also include the communication inside two elements. For those skilled in the art, the specific meaning of the above-mentioned terms in the present application can be understood according to the specific circumstances.

[0132] In addition, the terms "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0133] Although the embodiments of the present application have been shown and described above, it can be understood that the above-mentioned embodiments are exemplary and cannot be understood as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above-mentioned embodiments within the scope of the present application.

Claims

1. A linear acceleration environmental test platform, characterized by, The utility model relates to a device acceleration test system, which comprises the following parts: a platform body; a guide rail assembly comprising linear guide rails laid on the platform body; a spring assembly comprising a plurality of springs symmetrically distributed on both sides of the linear guide rails, wherein one end of each spring is a fixed end and the other end is a stretchable end; a spring stretching assembly comprising a fixed part, a movable part and a movable part fixing tool, wherein the fixed part is connected with the fixed end of each spring, the movable part comprises a movable seat slidably connected to the linear guide rails and an adapter seat symmetrically connected to both sides of the movable seat, the surface of the movable seat facing the device assembly tool is a plane as an abutting surface for contacting the device assembly tool, and the adapter seat is connected with the stretchable end of each spring and used for stretching the stretchable end of the spring assembly to a predetermined stretching position and fixing or releasing the movable part through the movable part fixing tool; a device assembly tool slidably connected to the linear guide rails and having a measured device mounted thereon, wherein when the stretchable end of the spring assembly is stretched to the predetermined stretching position, the device assembly tool abuts against the movable part of the spring stretching assembly, so that the device assembly tool is driven by the restoring force of the spring assembly to move linearly along the linear guide rails at a linear acceleration after the movable part is released, and the predetermined stretching position is configured to keep the tension of each spring symmetrically distributed on both sides of the linear guide rails balanced relative to the axis of the linear guide rails before being released; a detection unit comprising an inertial measurement module mounted on the device assembly tool and used for detecting the real-time acceleration and angular velocity of the measured device; a control system used for obtaining first acceleration information measured by the inertial measurement module and second acceleration information read by the measured device, comparing and analyzing the first acceleration information and the second acceleration information, and obtaining a comparison and analysis result.

2. The linear acceleration environmental test platform of claim 1, wherein, The fixed part comprises two groups of fixed seats symmetrically arranged on both sides of the linear guide rails, wherein each fixed seat comprises a vertical plate connected with the platform body and a horizontal plate horizontally extending outward from the vertical plate, and the horizontal plate is connected with the fixed end of the spring.

3. The linear acceleration environmental test platform of claim 1, wherein, The movable part fixing tool is arranged on the linear guide rails and comprises a first horizontal surface, a vertical surface and a second horizontal surface, wherein a gap is arranged between the first horizontal surface and the vertical surface, the shape of the gap matches the part of the movable seat protruding from the upper surface of the linear guide rails, and the gap can limit the transverse displacement of the movable seat, the first horizontal surface is provided with a fixing member for fixing or releasing the movable part, the fixing member is connected with the movable seat, and the second horizontal surface is detachably connected with the platform body.

4. The linear acceleration environmental test platform of claim 1, wherein, The bottom surface of the linear guide rails is fixed with a buffer part, and the buffer part is arranged at the terminal position of the movable part of the spring stretching assembly; the buffer part comprises a buffer connecting plate connected with the linear guide rails and a first buffer layer extending downward from the buffer connecting plate; the movable part is connected with a second buffer layer, and the second buffer layer is configured to finally impact on the first buffer layer after the movable part is released.

5. The linear acceleration environmental test platform of claim 1, wherein, The detection unit further comprises a linear grating ruler installed on the moving path of the device to be measured and parallel to the linear guide rail, and a reading head of the linear grating ruler is arranged on the device assembly tool for measuring the relative position of the device to be measured in the linear direction to verify the self-position data read in the device to be measured.

6. A test method for the linear acceleration environment test platform according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: S1: installing the device to be measured and the inertial measurement module on the device assembly tool, and slidably installing the device assembly tool on the linear guide rail; S2: calculating and obtaining the predetermined stretching position of the spring assembly according to the spring theoretical model, stretching the spring assembly to the predetermined stretching position through the movable part of the spring stretching assembly, and fixing the spring assembly through the movable part fixing tool; S3: moving the device assembly tool to the position of the movable part of the spring stretching assembly and abutting against the movable part, and then releasing the movable part to drive the device assembly tool to move linearly along the linear guide rail at a linear acceleration by the restoring force of the spring assembly; S4: synchronously obtaining the first acceleration information measured by the inertial measurement module and the second acceleration information read by the device to be measured during the acceleration movement, comparing and analyzing the first acceleration information and the second acceleration information, and verifying the accuracy of the acceleration data obtained by the inertial measurement module based on the comparison and analysis result.

7. The method of claim 6, wherein the method further comprises: The establishment and compensation method of the spring theoretical model comprises: a. obtaining the initial deformation of each spring in the spring assembly; b. based on the initial deformation, obtaining the total deformation of each spring in the spring assembly after the displacement of one end of the spring assembly is generated; c. based on the total deformation, calculating the spring force of a single spring according to Hooke's law, and obtaining the sum of the spring forces of each spring in the spring assembly at the initial position as the initial spring total force; d. based on the total deformation, the spring force of a single spring and the initial spring total force, calculating the sum of the spring forces of each spring in the spring assembly after displacement as the displacement spring total force, and obtaining the relationship model between the displacement spring total force and the overall displacement of the spring assembly; e. taking the multiple sets of overall displacement of the spring assembly and the corresponding displacement spring total force data obtained by executing steps b to d multiple times as a training set, and solving the error compensation model representing the relationship between the displacement spring total force and the overall displacement by a regression fitting algorithm; f. using the test data not involved in the modeling of step e as a verification set to test the prediction performance of the error compensation model; the verification process comprises: stretching the spring assembly to a predetermined position according to the spring theoretical model, collecting the actual spring total force at the predetermined position, and quantitatively evaluating the accuracy and reliability of the error compensation model by calculating the error between the actual spring total force and the spring total force predicted by the error compensation model according to the predetermined position; g. if the verification result of step f meets the requirements, the error compensation model is applied to the control system to obtain the overall stretching displacement of the spring assembly according to the target spring total force, and the predetermined stretching position is obtained.

8. The method of claim 7, wherein the method further comprises: The calculation formulae of steps a to d comprise: 1) initial deformation variable x 0i By the following equation: x 0i = L - L 0i where L is the initial length of the spring, L 0i is the natural length of the ith spring; if x 0i > 0, it means that the spring is initially in tension with an initial tension; if x 0i < 0, it means that the spring is initially in compression. 2) the total deformation of the spring x i By the following equation: x i = (L + Δ) - L 0i = (L - L 0i ) + Δ = x 0i + Δ wherein, Δ is the displacement generated when the spring moves; 3) spring force F of the individual spring i is obtained by the following equation: F i =k i ×x i F = F0+ kx i i F = F0+ kx i i F = F0+ kx i 4) the initial spring total force F0 is obtained by the following formula: F0 =∑F i0 F i0 =k i ×x 0i where F0 is the sum of the spring forces at the initial position of all springs; x 0i is the initial deformation of the i-th spring, and x 0i = L - L 0i , F i0 is the spring force of the i-th spring at the initial position. 5) The total force F of the spring after displacement is obtained by the following formula: F =∑F i The above formulas are combined to obtain: F = F0+ (Σk i ) x Δ 6) The relationship model between the total force F of the spring after displacement and the displacement Δ is established: Let Σk i be the equivalent stiffness coefficient K = Σk i , F = F0+ K x Δ; In the formula, K is the sum of the stiffness coefficients of all springs.

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