Linear acceleration environment test platform and test method

Abstract

The invention discloses a linear acceleration environment test platform and a test method. The test platform comprises a platform body, a control system, and a guide rail assembly, an equipment assembly tool, a spring assembly, a spring stretching assembly and a detection unit which are arranged on the platform body, the equipment assembling tool is arranged on the guide rail assembly and is used for installing tested equipment; the spring assembly comprises a plurality of springs which are symmetrically distributed on the two sides of the guide rail assembly. The spring stretching assembly is used for stretching the spring assembly to a preset stretching position, the equipment assembling tool abuts against the spring stretching assembly, and the spring stretching assembly is released to drive the equipment assembling tool to do linear accelerated motion. The invention further comprises a test method of the linear acceleration environment test platform. The device is simple in structure and low in manufacturing cost, can effectively simulate the real dynamic response of the tested device under the action of the linear acceleration, carries out refined evaluation on the independence performance of the tested device, and is especially suitable for batch test requirements of inertial navigation devices, low-cost whole 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 Centrifuge overload test is a ground test method that simulates the sustained radial acceleration of products by generating controllable centrifugal force through high-speed rotation. However, centrifuges are mainly used to simulate radial acceleration, while aircraft and supporting equipment are mainly subjected to linear acceleration in actual flight. Therefore, centrifuges 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.

[0004] (2) Rocket sled test Rocket sled overload test is a test method that simulates the high overload flight environment of aircraft through ground facilities to verify the performance of the aircraft. Its working principle is: using the boost engine carried by the rocket sled itself and the test engine as the power source, driving the rocket sled system to move at high speed on a special slide rail, thereby simulating the flight motion environment of the aircraft, completing the performance test and data acquisition of the aircraft under high acceleration conditions. This test can simulate the high acceleration, strong vibration and aerodynamic heat coupling environment of the aircraft in the flight process by propelling the sled to slide at high speed on a long track (such as a 9km track), providing a basis for evaluating the navigation precision, signal stability and other core indicators of the aircraft under dynamic overload.

[0005] However, the rocket sled overload test has significant cost and facility threshold problems: it requires the construction of a precision track of several kilometers and supporting deceleration systems (such as water tank deceleration devices), and the cost of rocket fuel consumption, test control equipment loss and post-maintenance for a single test is high. Therefore, this method cannot meet the batch demand for overload test of current low-cost aircraft.

[0006] (3) Whole machine flight test The whole machine flight test tests the comprehensive performance of the aircraft through the physical flight test, and the measured data can be obtained in the real flight environment. However, this test method has significant limitations: on the one hand, the whole machine flight test has high cost, high complexity, is restricted by environmental factors such as weather and airspace, has poor repeatability, and 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.

[0007] 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 ability. SUMMARY

[0008] 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.

[0009] The technical scheme of the present application is: The linear acceleration environment test platform of the present application comprises: a platform body; a guide rail assembly comprising a linear guide rail laid on the platform body; a spring assembly comprising a plurality of springs symmetrically distributed on both sides of the linear guide rail, wherein one end of each spring is a fixed end and the other end is a stretchable end which can be released; 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 is slidingly connected to the linear guide rail and connected with the stretchable end of each spring, and the movable part fixing tool is used to fix or release the movable part when the stretchable end of the spring assembly is stretched to a predetermined stretching position; a device assembly tool slidingly connected to the linear guide rail, wherein a measured device is installed on the device assembly tool, 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 device assembly tool is driven to move linearly along the linear guide rail by the restoring force of the spring assembly when the movable part is released; a detection unit comprising an inertial measurement module installed on the device assembly tool, used to detect the real-time acceleration and angular velocity of the measured device; The control system is used for acquiring first acceleration information measured by the inertial measurement module and second acceleration information read by the measured device itself, comparing and analyzing the first acceleration information and the second acceleration information, and acquiring a comparison and analysis result.

[0010] 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.

[0011] 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 tool is a plane as an abutting surface in contact with the equipment assembly tool, and the adapter seat is connected with the stretching end of the spring.

[0012] Further, the movable part fixing tool arranged on the linear guide rail comprises a first horizontal plane, a vertical plane and a second horizontal plane, a gap is arranged between the first horizontal plane and the vertical plane, the shape of the gap is matched with the part protruding from the upper surface of the linear guide rail on the movable seat, the gap can limit the transverse displacement of the movable seat, the fixing tool for fixing or releasing the movable part is arranged on the first horizontal plane, the fixing tool is connected with the movable seat of the movable part, and the second horizontal plane is detachably connected with the platform body.

[0013] 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.

[0014] Further, the detection unit further comprises a linear grating ruler installed on the movement path of the measured device and parallel to the linear guide rail, and a reading head of the linear grating ruler is arranged on the equipment assembly tool and used for measuring the relative position of the measured device in the linear direction, so as to be compared and verified with the self-position data read in the measured device.

[0015] The test method of the linear acceleration environment test platform comprises the following steps: S1: installing the measured device and the inertial measurement module on the equipment assembly tool, and slidably installing the equipment assembly tool on the linear guide rail; S2: calculating and acquiring a predetermined stretching position of the spring assembly according to a spring theoretical model, stretching the spring assembly to the predetermined stretching position through the movable part of the spring stretching assembly, and fixing through the movable part fixing tool. S3: moving the device assembly tool to the active part position of the spring stretching assembly and abutting with it, and then releasing the active 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; S4: during the acceleration motion, synchronously acquiring the first acceleration information measured by the inertial measurement module and the second acceleration information read by the measured device itself, 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.

[0016] Further, the spring theoretical model establishment and compensation method comprises: a. acquiring the initial deformation amount of each spring in the spring assembly; b. based on the initial deformation amount, acquiring the total deformation amount 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 amount, calculating the spring force of a single spring according to Hooke's law, and acquiring the sum of the spring forces of each spring in the spring assembly at the initial position as the initial spring total force; d. according to the total deformation amount, 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 acquiring the relationship model between the displacement spring total force and the overall displacement amount of the spring assembly; e. taking the multiple sets of overall displacement amount of the spring assembly and the corresponding displacement spring total force data acquired 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 amount 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 for obtaining the overall stretching displacement of the spring assembly according to the target spring total force to obtain the predetermined stretching position.

[0017] Further, the calculation formulas of steps a-d comprise: 1) Initial deformation amount x 0i The initial deformation amount x is obtained by the following formula: x 0i =L-L 0i Where 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 tension with an initial tension; if x 0i <0, it means that the spring is initially in compression; 2) the total deformation x i of the spring is obtained by the following formula: x i =(L+Δ)-L 0i =(L-L 0i )+Δ=x 0i +Δ Where Δ is the displacement generated when the spring moves; 3) the spring force F i of a single spring is obtained by the following formula: F i =k i ×x i Where F i is the spring force of the i-th spring, and k i is the stiffness coefficient of the i-th spring; 4) the initial total spring force F0 is obtained by the following formula: F0=ΣF 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, x 0i =L-L 0i , and F i0 is the spring force at the initial position of the i-th spring; 5) the total spring force F after displacement is obtained by the following formula: F=ΣF i The above formulas are combined to obtain: F=F0+(Σk i )×Δ 6) the relationship model between the total spring force F after displacement and the displacement Δ is established: Let Σk i be the equivalent stiffness coefficient K=Σk i , and F=F0+K×Δ. Where K is the sum of the stiffness coefficients of all springs.

[0018] Advantages of the present application: (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 and is not restricted by environmental factors, and is particularly suitable for batch test requirements of inertial navigation devices, low-cost aircrafts and the like; (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, 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 the inertial navigation device which is 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; (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, so as to avoid the situation that the test fails due to excessive friction on the slider caused by the lateral torque or the measured equipment is pulled out of the linear guide rail, and a non-interference linear dynamics environment is provided for the measured equipment, ensuring the high fidelity of the test environment and eliminating the error introduced by the system itself; (4) By arranging the buffer part, the spring stretching assembly can be prevented from being damaged due to overload, and the service life thereof is greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a structure schematic view of the movable part fixed tool fixing the movable part (the spring assembly is not shown) of the embodiment of the present application; Figure 2 is a structure schematic view of the movable part and the movable part fixed tool being separated.

[0020] The drawing mark is explained as follows: 1, platform body; 2, guide rail assembly; 3, equipment assembly tool; 4, spring assembly; 5, spring stretching assembly; 6, measured equipment; 7, inertial measurement module; 8, linear grating ruler; 9, buffer part; 21, linear guide rail; 22, first slider; 41, spring; 51, fixed part; 52, movable part; 53, second slider; 54, movable part fixed tool; 61, clamp; 81, reading head; 91, buffer connecting plate; 92, first buffer layer; 521, movable seat; 522, adapter seat; 523, second buffer layer; 541, pull ring type indexing pin. DETAILED DESCRIPTION

[0021] The present application will be further described in detail below in combination with the drawings of the specification and specific embodiments.

[0022] like Figure 1 and Figure 2 As shown: A linear acceleration environmental test platform, including a platform body 1, a control system, and a guide rail assembly 2, an equipment 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 laid on the platform body 1, and the equipment assembly tool 3 is arranged on the guide rail assembly 2 for installing the device under test 6; the spring assembly 4 includes a plurality of springs 41, each spring is installed on the spring stretching assembly 5 and is symmetrically distributed on both sides of the guide rail assembly 2; the spring stretching assembly 5 is used to stretch the spring assembly 4 as a whole to a predetermined stretching position, the equipment assembly tool 3 abuts against the spring stretching assembly 5, and by releasing the spring stretching assembly 5, the equipment assembly tool 3 and the device under test 6 assembled thereon are driven to perform linear acceleration motion; the detection unit is used to detect 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 to obtain the acceleration data and position data measured by the detection unit, as well as the acceleration data and position data read by the device under test itself, and perform comparative analysis one by one to obtain comparative analysis results, so as to verify the accuracy of the acceleration data and position data obtained by the detection unit based on the comparative analysis results.

[0023] In this embodiment, the guide rail assembly 2 is used to provide a test infrastructure for the test platform, including a linear guide rail 21 laid on the platform body 1 and a first slider 22 slidably connected to the linear guide rail. Among them, 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 this embodiment, it is preferably designed as a double rail. The first slider 22 is connected to the equipment assembly tool 3, that is, it is arranged at the bottom of the equipment assembly tool 3, and is used to carry the equipment assembly tool 3 and the device under test 6 thereon, and ensure that the load is distributed in a predetermined manner. Preferably, the equipment assembly tool 3 is detachably connected to the first slider 22, such as by screwing or clamping, so as to facilitate the replacement of matching equipment assembly tooling for different devices under test.

[0024] In this embodiment, the spring stretching assembly 5 includes a fixed part 51, a movable part 52, a second slider 53 and a movable part fixing tool 54; wherein the second slider 53 is slidably connected to the linear guide rail 21, and the movable part 52 is installed on the second slider 53, and can move on the linear guide rail 21 along the second slider 53; the movable part fixing tool 54 is used to fix the movable part 52 to the predetermined stretching position when the movable part 52 drives the spring assembly 4 to move to the predetermined stretching position; the fixed part 51 and the movable part 52 are installed on the platform body 1 and distributed on both sides of the equipment assembly tool 3, and one end of each spring 41 of the spring assembly serves as a fixed end, connected to the fixed part 51, and the other end serves as a stretching end, connected to the movable part 52.

[0025] 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.

[0026] 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 to facilitate abutting with 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.

[0027] 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 plane, a vertical plane and a second horizontal plane; wherein the gap formed by the first horizontal plane and the vertical plane 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 plane 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 plane, 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 plane 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.

[0028] In this 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, which 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 test failure caused by the excessive friction force on the sliding block or the measured equipment pulled out of the linear guide rail due to the lateral moment.

[0029] 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 to mount 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.

[0030] 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.

[0031] 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: 1. Initial deformation: is the deformation of the spring at the initial position, which is obtained by the following formula: x 0i = L - L 0i (1) In the formula, L is the distance between the two ends of the spring in the initial state, that is, the initial length, and L 0i is the natural length of the i-th spring. If x 0i > 0, it means that the spring is initially in tension state with initial tension; if x 0i < 0, it means that the initial is in compression state.

[0032] 2. Total deformation of the spring: is the difference between the distance between the two ends of the spring when pulling one end and the natural length of the spring, which is obtained by the following formula: x i = (L + Δ) - L 0i = (L - L 0i ) + Δ = x 0i + Δ (2) In the formula, x i is the total deformation, and Δ is the displacement generated when the spring moves, so the distance between the springs becomes L + Δ.

[0033] 3. Spring force of a single spring: the spring force of each spring is related to the spring coefficient, according to Hooke's law, that is: F i = k i x i (3) 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.

[0034] It can be understood that for the direction of the spring force, when the spring is stretched (x i > 0), the spring force behaves as a pulling force, trying to make the spring contract; when the spring is compressed (x i < 0), the spring force behaves as a pushing force, trying to make the spring stretch.

[0035] 4. Initial total spring force: is the sum of the spring forces of each spring at the initial position, that is: F0 = ΣF i0 (4) F i0 = k i x 0i (5) In the formula, F0 is the sum of the spring forces of all springs at the initial position, that is, the initial total spring force; x 0i is the initial deformation of the i-th spring, and x 0i = L - L 0i, F i0 F0is the spring force of the initial position of the i-th spring.

[0036] 5, the total force of the spring after displacement: refers to the total spring force of the spring assembly after a certain displacement of one end, that is, F=ΣF i (6) In the formula, F is the total force of the spring, that is, the sum of the spring forces of all springs.

[0037] 6, the comprehensive formula (1)~(6) can be obtained: F=F0+(Σk i )×Δ (7) 7, 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 , so the relationship between the total force F of the spring after displacement and the displacement Δ is: F= F0+K×Δ (8) In the formula, F0is the sum of the spring forces of all springs at the initial position (the spring force when Δ=0), and K is the sum of the stiffness coefficients of all springs.

[0038] It can be said that the force-displacement relationship of the spring assembly can be described by the theoretical model within the elastic limit, but in the real environment, due to the existence of non-linear factors such as clearance and friction in the spring assembly, the theoretical model will have deviations, and the error compensation model is established by sample training in the embodiment to determine the relationship between the input and the output. Specifically: For each data point, define the error e as the deviation between the actual value and the theoretical value, and the error e and the displacement x are linearly related, which is suitable for the scene where the system error is dominant and the law is simple:

[0039] In the formula, x is the displacement of the spring assembly, is a standard normal distribution error term with a mean of 0; β 0、 β 1 is the regression coefficient; The error compensation model formula of the force-displacement relationship of the spring assembly is:

[0040] 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.

[0041] For x1, x2, …, x kn sets of observations (x t ) and calculate the error term that follows a standard normal distribution with a mean of 0 , t=1,2,...,n (n>k+1), they satisfy the relationship:

[0042] The straight line with the smallest total gap between the model prediction result and the actual result is taken as the final straight line, and the loss function is defined as the mean square error. Its goal is to , the mean square error is expressed as:

[0043] To find the optimal parameters, to minimize the mean square error, take the derivative of the mean square error and take the coefficient when the derivative is zero , the mean square error is derived as follows:

[0044] Using actual total spring force and spring assembly displacement data collected from multiple tests as the training set, a linear regression fit was performed to develop an error compensation model for the relationship between the total spring force F and the spring assembly displacement x. The predictive performance of the error compensation model was then tested using "test data not used in modeling" (10%-20% of the samples were reserved as a validation set). During validation, the spring assembly was stretched to a predetermined position based on the theoretical spring model, and the actual total spring force at that position was measured. The accuracy and reliability of the error compensation model were quantitatively assessed by calculating the error between this actual force and the force predicted by the error compensation model.

[0045] 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 spring total force and obtain the predetermined stretching position.

[0046] The testing method of this embodiment specifically includes the following steps: S101 : Fix the device under test 6 and the inertial measurement module 7 on the device assembly tool 3 , and slidably install the device assembly tool 3 on the linear guide rail 21 .

[0047] Specifically, the device under test 6 is fastened to the slot of the device assembly tool 3 by a clamp 61. The device under test 6 can be, but is not limited to, a complete inertial navigation device, an independent acceleration sensor assembly, or a low-cost aircraft, and the device under test has acceleration data reading and positioning navigation functions.

[0048] S102 : Calculate and obtain a predetermined stretching position of the spring assembly 4 according to a theoretical model of the spring, stretch the spring assembly 4 to the predetermined stretching position via the movable portion 52 of the spring stretching assembly, and fix it via the movable portion fixing fixture 54 .

[0049] Specifically, in order to make the equipment assembly tooling do linear acceleration motion, one end of the spring assembly 4 is fixed by the fixed part 51 of the spring tension assembly 5, and the other end is connected to the movable part 52; the spring assembly 4 is pulled to a predetermined tension 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 tooling 54.

[0050] S103: Move the equipment assembly tooling 3 along the first slider 22 to the position of the movable part of the spring tension assembly and abut it, and then release the movable part 52, so that the restoring force of the spring assembly 4 drives the equipment assembly tooling 3 to do linear acceleration motion along the linear guide rail.

[0051] Specifically, when testing, the equipment assembly tooling 3 is in contact with the movable seat 521, and the tension of the spring assembly 4 can be converted into the acceleration of the equipment assembly tooling 3 through the contact between the two, and then the pull ring type indexing pin 541 of the movable part fixing tooling 54 is rotated out, releasing the movable part 52, so that the movable part 52 pushes the equipment assembly tooling 3 to do linear acceleration motion along the linear guide rail 21 under the restoring force of the spring assembly 4.

[0052] S104: During the acceleration motion, the first acceleration information measured by the inertial measurement module 7 and the second acceleration information read by the measured equipment itself are synchronously acquired, the first acceleration information is compared and analyzed with the second acceleration information, and based on the comparison and analysis result, the accuracy of the acceleration data obtained by the inertial measurement module 7 is verified.

[0053] Specifically, releasing the movable part 52 of the spring tension assembly can take the equipment assembly tooling 3 and the measured equipment 6 assembled thereon to do linear acceleration motion along the linear guide rail 21, and at the same time, the high-precision inertial measurement module 7 synchronously acquires the acceleration data of the test process, and the detection data of the inertial measurement module 7 and the data read in the measured equipment 6 are compared through the acquisition system (such as the upper computer, computer or controller, etc.), so as to ensure the accuracy of the acceleration data obtained by the inertial measurement module 7. For example: taking the acceleration data read by the measured equipment 6 itself as the reference, the accuracy of the data obtained by the external inertial measurement module (IMU) is verified. The purpose of this verification is to evaluate the performance of the IMU, and to provide a basis for subsequent data use or error compensation. After verification, the IMU data can be accepted by the system; if not, the equipment needs to be replaced or calibrated according to the error analysis result.

[0054] At the same time, the linear grating ruler 8 and the reading head 81 cooperate to acquire the relative position of the measured equipment 6, so as to compare and verify the accuracy of the position data of the satellite navigation read in the measured equipment.

[0055] 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, so that when the second buffer layer 523 on the movable part hits the first buffer layer 92, the spring tension assembly can be protected from damage due to overload.

[0056] In addition, the term "connected" should be interpreted broadly, for example, can include fixed connection, detachable connection or integral connection; can include direct connection, can also be indirectly connected through an intermediate medium, and can also include the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0057] 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 with "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.

[0058] Although the embodiments of the present application have been shown and described above, it can be understood that the above 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 embodiments within the scope of the present application.

Claims

1. A linear acceleration environmental test platform, characterized by, The utility model relates to a kind of device for testing the acceleration of device, including: Platform body; Rail assembly, including linear guide rail, is laid on the platform body; Spring assembly, including several springs, symmetrically distributed in the two sides of linear guide rail;And the one end of each spring is fixed end, the other end is the stretchable end; Spring stretching assembly, including fixed part, movable part and movable part fixing tool;The fixed part is connected with the fixed end of each spring;The movable part is slidably connected on linear guide rail, and is connected with the stretchable end of each spring, for stretching the stretchable end of the spring assembly to predetermined stretch position, and the movable part is fixed or released by the movable part fixing tool; Device assembly tool is slidably connected on the linear guide rail, and the measured device is installed on it;And when the stretchable end of spring assembly is stretched to predetermined stretch position, device assembly tool and the movable part of spring stretching assembly abut, so that the movable part is released, and the restoring force of spring assembly drives device assembly tool to make linear acceleration along linear guide rail; Detection unit, including inertial measurement module, the inertial measurement module is installed on the device assembly tool, for detecting the real-time acceleration and angular velocity of measured device; Control system, for obtaining the first acceleration information measured by the inertial measurement module, and the second acceleration information read by measured device itself, comparing and analyzing the first acceleration information with the second acceleration information, obtaining comparison and analysis result.

2. The linear acceleration environmental test platform of claim 1, wherein, The fixed part includes two groups of fixed seats, respectively symmetrically arranged on the two sides of linear guide rail, and the fixed seat includes a vertical plate connected with the platform body and a horizontal plate 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 includes a movable seat slidably connected on the linear guide rail and an adapter seat symmetrically connected on the two sides of the movable seat;The surface of the movable seat facing the device assembly tool is a plane, which serves as an abutting surface in contact with the device assembly tool;The adapter seat is connected with the stretchable end of the spring.

4. The linear acceleration environmental test platform of claim 3, wherein, The movable part fixing tool is arranged on the linear guide rail and includes a first horizontal surface, a vertical surface and a second horizontal surface;A gap is provided between the first horizontal surface and the vertical surface, and the shape of the gap matches the part of the movable seat protruding from the upper surface of the linear guide rail, so as to limit the lateral displacement of the movable seat;The first horizontal surface is provided with a fixing member for fixing or releasing the movable part, and the fixing member is connected with the movable seat;The second horizontal surface is detachably connected with the platform body.

5. The linear acceleration environmental test platform of claim 3, wherein, 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 includes 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.

6. The linear acceleration environmental test platform according to claim 1, characterized in that: The detection unit further includes a linear grating ruler, which is installed on the moving path of the measured device and parallel to the linear guide rail, and the reading head of the linear grating ruler is arranged on the device assembly tool, for measuring the relative position of the measured device in the linear direction, so as to compare and verify the self-position data read in the measured device.

7. A test method for the linear acceleration environment test platform according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: S1: mounting the device under test and the inertial measurement module on a device assembly tool, and slidably mounting the device assembly tool on a linear guide rail; S2: calculating and obtaining a predetermined stretching position of the spring assembly according to a 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 first acceleration information measured by the inertial measurement module and second acceleration information read by the device under test 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.

8. The method of claim 7, wherein the method further comprises: The establishment and compensation method of the spring theoretical model comprises: a. obtaining initial deformation amounts of the springs in the spring assembly; b. based on the initial deformation amounts, obtaining total deformation amounts of the springs in the spring assembly after one end of the spring assembly is pulled to generate displacement; c. based on the total deformation amounts, calculating spring forces of the single springs according to Hooke's law, and obtaining the sum of the spring forces of the springs in the spring assembly at the initial position as an initial spring total force; d. based on the total deformation amounts, the spring forces of the single springs and the initial spring total force, calculating the sum of the spring forces of the springs in the spring assembly after displacement as a displacement spring total force, and obtaining a relationship model between the displacement spring total force and the overall displacement of the spring assembly; e. taking multiple sets of the 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 an error compensation model representing the relationship between the displacement spring total force and the overall displacement of the spring assembly by a regression fitting algorithm; f. using 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 an 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, applying the error compensation model to a control system to obtain the overall stretching displacement of the spring assembly according to a target spring total force, and obtaining the predetermined stretching position.

9. The method of claim 8, wherein the method further comprises: determining a test time for the test; and determining a test time for the test based on the test time and the test time. The calculation formulas 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) the elastic force F of the single 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 displacement spring total force F is obtained by the following formula: F =∑F i The relationship model between the displacement spring total force F and the displacement Δ is established by the above formulas: F=F0+(Σk i )×Δ wherein K is the sum of the stiffness coefficients of all the springs. Let Σk i be the equivalent stiffness coefficient K = Σk i , F = F0+ K x Δ; ​

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