Mems accelerometer centrifuge test structure, system, and method

Abstract

The application discloses a MEMS accelerometer centrifugal test structure, system and method, the structure comprises a centrifugal transfer tool, a centrifugal test tool turntable, a test transfer tool, a chip test board and a plurality of clamp mechanisms; the system comprises a centrifugal machine turntable and eight MEMS accelerometer centrifugal test structures; the method is suitable for the MEMS accelerometer centrifugal test system, realizes test and full-scale calibration of the accelerometer chip, obtains indexes of zero offset and nonlinearity, and evaluates cross-axis crosstalk of the accelerometer chip; through the test tool turntable, forward and reverse tests of the accelerometer full scale are realized without disassembly; the cross-shaped test board is provided with X and Y direction clamps, X, Y and X-Y dual-axis accelerometers can be tested and cross-axis crosstalk can be evaluated, and the system has strong versatility; the clamp is integrated on the circuit board, cable damage is prevented, and safety is higher; the structure is integrated and adapted to batch production, the clamp is easy to install and compatible with multiple can sizes, and test efficiency is further improved.

Description

Technical Field

[0001] This invention relates to the field of accelerometer technology, and in particular to a centrifugal testing structure for MEMS accelerometers. Background Technology

[0002] MEMS accelerometers (microelectromechanical systems accelerometers) are miniature sensors manufactured using semiconductor micromachining technology. They are used to measure the acceleration, vibration, tilt, and other motion states of objects and are widely used in automotive, industrial, and aerospace fields. Accurate evaluation of accelerometer performance directly impacts its application in these fields.

[0003] Centrifuges, used as testing equipment for MEMS accelerometers, generate controllable centripetal acceleration through rotation, providing a high-precision acceleration input environment for the accelerometers. Accelerometers are tested and calibrated within the continuously changing acceleration field generated by the centrifuge to obtain numerous key performance indicators, such as scaling factor nonlinearity, symmetry, and measurement range.

[0004] Accelerometer centrifugal testing fixtures, serving as fixed accelerometer devices on centrifuges, play a crucial role in accelerometer centrifugal testing. Currently, traditional accelerometer centrifugal testing fixtures encounter the following problems: 1. During ±1g calibration, the accelerometer requires full power. However, in traditional structures, after +1g calibration, the accelerometer needs to be disassembled and reinstalled onto the -1g fixture. This installation process can easily lead to power outages and introduce installation errors, significantly impacting test accuracy. 2. Traditional centrifugal testing fixtures have a single testing direction, allowing testing only in one direction. To test XY dual-axis accelerometers or assess cross-axis crosstalk, the fixture needs to be replaced, severely impacting production efficiency. 3. In traditional centrifugal testing, when the centrifuge is rotating at high speed, the transmission cable can be thrown outwards, severely affecting the data cable's lifespan and impacting production safety. 4. If traditional centrifugal testing fixtures are used in mass production, a significant amount of time is spent installing and disassembling the test board, impacting testing efficiency and increasing fixture wear and tear. 5. Traditional centrifugal testing fixtures are typically designed for specific models or sizes of accelerometers, making them incompatible with other sizes. Therefore, there is an urgent need for a highly reliable, versatile, and convenient centrifugal testing fixture for accelerometers that can be applied in mass production. Summary of the Invention

[0005] To address the aforementioned technical problems, one technical solution adopted by this invention is: a MEMS accelerometer centrifugal testing structure, which includes:

[0006] Centrifugal adapter 1, which provides a mounting carrier for the adapter and allows the adapter to be mounted on a centrifuge;

[0007] Centrifugal testing fixture turntable 2 is mounted on centrifugal transfer fixture 1 by means of a fixing component, and its center is concentric with the center of centrifugal transfer fixture 1.

[0008] Test adapter 3: The test adapter 3 is cross-shaped, and the four corners of the test adapter 3 are fixedly installed on the centrifugal test fixture turntable 2 by locking parts;

[0009] Chip test board 4; The chip test board 4 is fixedly mounted on the test adapter 3 by a locking component. The chip test board 4 is cross-shaped, with the horizontal axis of the chip test board 4 defined as the X-axis and the vertical axis of the chip test board 4 defined as the Y-axis. The chip test board 4 is used to collect and transmit accelerometer data during testing.

[0010] Multiple clamping mechanisms 5 are used to clamp the accelerometer onto the structure; the multiple clamping mechanisms 5 are uniformly fixedly mounted on the surface of the chip test board 4 along the X-axis and Y-axis of the chip test board 4.

[0011] Furthermore, the clamping mechanism 5 located on the X-axis of the chip test board 4 is defined as the Y-axis clamping mechanism 501; the clamping mechanism 5 located on the Y-axis of the chip test board 4 is defined as the X-axis clamping mechanism 502; the X-axis clamping mechanism 502 and the Y-axis clamping mechanism 501 have the same structure.

[0012] Both the X-axis clamping mechanism 502 and the Y-axis clamping mechanism 501 include:

[0013] The outer frame of the fixture 503 is fixedly mounted on the chip test board 4;

[0014] The housing groove 504 is used to place the accelerometer inside the housing groove 504; the housing groove 504 is formed at the bottom inside the outer frame 503 of the fixture;

[0015] Two springs 505 are respectively mounted on opposite surfaces inside the outer frame 503 of the fixture;

[0016] Two clamping plates 506 are respectively mounted on corresponding springs 505;

[0017] Two clamping combs 507 are respectively installed at opposite edges of the outer frame 503 of the clamp, and the clamping combs 507 are used to clamp the upper surface of the tube shell of the accelerometer.

[0018] The clamping plate 506 presses against the outer surface of the accelerometer housing by the elastic force of the spring 505, clamping the accelerometer within the outer frame 503 of the fixture.

[0019] Furthermore, the short side of the clamping outer frame 503 of the X-axis clamping mechanism 502 and the long side of the clamping outer frame 503 of the Y-axis clamping mechanism 501 are both provided with test fixture pin position markers.

[0020] One of the technical solutions adopted in this invention is: a MEMS accelerometer centrifugal testing system, which includes: a centrifuge turntable 6 and eight of the above-mentioned MEMS accelerometer centrifugal testing structures;

[0021] Among them, the eight MEMS accelerometer centrifugal test structures are evenly distributed on the edge of the centrifuge turntable 6 with the centrifuge turntable 6 as the center;

[0022] The centrifuge turntable 6 is connected to the centrifuge drive shaft, which causes the centrifuge turntable 6 to rotate and generate centrifugal force;

[0023] The centrifuge turntable 6 is provided with at least one slip ring 7; the data cable for connecting the chip test board 4 is connected to the electrical performance of the peripheral test and analysis system through the slip ring 7, so as to avoid the data cable being tangled and damaged due to the rotation of the centrifuge turntable 6.

[0024] One of the technical solutions adopted in this invention is: a MEMS accelerometer centrifugal testing method. This method is applicable to the aforementioned MEMS accelerometer centrifugal testing system, enabling the testing and full-scale calibration of the accelerometer, obtaining indicators of zero bias and nonlinearity, and evaluating the cross-axis crosstalk of the accelerometer. The method includes:

[0025] S1. Install the accelerometer in the X-axis clamping mechanism 502 or the Y-axis clamping mechanism 501 according to the direction of the sensitive axis.

[0026] S2. Perform a forward test on the accelerometer by rotating the centrifugal test fixture turntable 2 so that the forward direction of the accelerometer's sensitive axis is uniformly opposite to the center of the centrifuge turntable 6. The centrifugal test fixture turntable 2 is fixed on the centrifuge turntable 6 by a fixing component. Turn on the centrifuge and control the centrifuge speed to apply a preset centripetal acceleration to the accelerometer. Select forward test points according to the preset interval and perform a stepped forward test.

[0027] S3. After completing the positive test, perform a negative test on the accelerometer. Without disassembling the accelerometer, rotate the centrifuge test fixture turntable 2 so that the positive direction of the accelerometer's sensitive axis is uniformly pointed to the center of the centrifuge turntable 6. The centrifuge test fixture turntable 2 is fixed on the centrifuge turntable 6 by fasteners. Turn on the centrifuge and control the centrifuge speed to apply a preset centripetal acceleration to the accelerometer. Select negative test points according to the preset interval and perform a stepped negative test.

[0028] S4. The accelerometer output velocities at each positive and negative test point are acquired through the chip test board 4 and transmitted to the peripheral test analysis system to calculate the nonlinearity of the accelerometer. ;

[0029] S5. Mount the accelerometer on a chip fixture orthogonal to its sensitive axis. Rotate the centrifugal test fixture turntable 2 so that the non-sensitive axis of the accelerometer points to the center of the centrifuge turntable 6. Turn on the centrifuge and control its speed. When the accelerometer is subjected to acceleration in the non-sensitive axis direction, obtain the output value in the sensitive axis direction. .

[0030] Furthermore, S1 includes:

[0031] S101. Determine whether the sensitive axis direction of the accelerometer is the X-axis or the Y-axis, and determine the position marker of pin 1 of the MEMS accelerometer chip.

[0032] S102, the position marker of pin 1 of the chip corresponds to the position marker of pin 1 of the test fixture;

[0033] S103. The MEMS accelerometer with the X-axis sensitive axis or the MEMS accelerometer with the Y-axis sensitive axis is clamped by the X-axis clamping mechanism 502 and the Y-axis clamping mechanism 501.

[0034] Furthermore, in S103, the positive direction of the sensitive axis of the MEMS accelerometer with the X-direction sensitive axis clamped in the X-axis clamping mechanism 502 and the Y-axis clamping mechanism 501 is the positive X-axis direction of the chip test board 4;

[0035] Alternatively, the positive direction of the sensitive axis of the MEMS accelerometer with the Y-direction sensitive axis clamped in the X-axis clamping mechanism 502 and the Y-axis clamping mechanism 501 is the negative direction of the Y-axis of the chip test board 4.

[0036] Furthermore, in S2 and S3, the formula for calculating the preset centripetal acceleration 'a' applied to the accelerometer is as follows:

[0037] (Equation 1)

[0038] in This refers to the rotational speed of the centrifuge turntable. This is the distance between the center of the accelerometer and the centrifuge turntable.

[0039] Furthermore, S4 includes:

[0040] S401. Process the accelerometer output velocities at each positive and negative test point, and obtain the linear equation:

[0041] (Equation 2)

[0042] in, This represents the theoretical output value of the accelerometer under the action of the corresponding accelerometer. To obtain the scale factor across the entire accelerometer range, To determine the zero bias of the accelerometer at 0g, 1g is approximately... ;

[0043] S402, Calculated using the least squares method and Its formula is:

[0044] (Equation 3)

[0045] (Equation 4)

[0046] in, The accelerometer output value at a certain acceleration. For the corresponding accelerometer value, This represents the total number of accelerometers.

[0047] S403. Compare the output velocity of each accelerometer at each positive and negative test point with the theoretical value. The difference between them yields the maximum residual of the accelerometer. ;

[0048] S404. Calculate the nonlinearity of the accelerometer. :

[0049] (Equation 5)

[0050] in, This is the theoretical maximum output value of the accelerometer. This is the theoretical minimum output value of the accelerometer.

[0051] Furthermore, S5 includes:

[0052] The evaluation value of the cross-axis crosstalk of the accelerometer is calculated using the following formula:

[0053] (Equation 6)

[0054] in, This represents the output value along the sensitive axis when the input is at full scale.

[0055] Compared with the prior art, the present invention has the following beneficial effects: by adding a turntable to the centrifugal test fixture of the accelerometer, it is possible to perform full-scale testing of the accelerometer without disassembling the chip and the fixture. Furthermore, when the accelerometer is tested in reverse, it is only necessary to rotate the turntable of the test fixture to install the fixing pin, which greatly improves the testing efficiency of the accelerometer.

[0056] The test board adopts a cross-shaped test board. By adding chip fixtures in two different directions, X and Y, the test board can realize the testing of X, Y, and XY dual-axis accelerometers. Furthermore, it can also realize the evaluation of cross-axis crosstalk of accelerometers, and has a wider range of versatility.

[0057] By integrating the accelerometer test fixtures onto the circuit board, damage to external connection cables caused by excessive centrifugal force can be reduced. Compared to traditional external structures, this structure is safer and more reliable.

[0058] Compared to traditional single-tool structures, this invention features a more integrated design that is better suited for mass production.

[0059] By designing a chip clamping mechanism that is more convenient to install than traditional screw-operated clamping structures, the chip installation efficiency can be effectively improved. This clamping mechanism can accommodate accelerometers with different housing sizes, offering greater versatility in housing size selection. Attached Figure Description

[0060] Figure 1 This is a schematic diagram of the centrifugal testing structure of the MEMS accelerometer of the present invention.

[0061] Figure 2 This is a side view of the MEMS accelerometer centrifugal test structure of the present invention.

[0062] Figure 3 This is a rear view of the test adapter and chip test board of the present invention.

[0063] Figure 4 This is a schematic diagram of the test adapter tooling and multiple clamping mechanisms of the present invention.

[0064] Figure 5 This is a schematic diagram of the clamping mechanism of the present invention.

[0065] Figure 6 This is a schematic diagram of the structure of the spring and the clamping plate of the present invention.

[0066] Figure 7 This is a schematic diagram of the MEMS accelerometer centrifugal testing system of the present invention.

[0067] Figure 8 This is a schematic diagram of the installation of the Y-axis accelerometer of the present invention within the Y-axis clamping mechanism.

[0068] Figure 9 This is a schematic diagram of the Y-axis accelerometer of the present invention within the X-axis clamping mechanism.

[0069] Figure 10 This is a schematic diagram of the X-axis accelerometer of the present invention within the X-axis clamping mechanism.

[0070] Figure 11 This is a schematic diagram of the X-axis accelerometer of the present invention within the Y-axis clamping mechanism.

[0071] Figure 12 This is a schematic diagram of the forward test structure of the accelerometer of the present invention.

[0072] Figure 13 This is a schematic diagram of the negative test structure of the accelerometer according to the present invention.

[0073] Figure 14 This is a schematic diagram of the structure for the forward test of cross-axis crosstalk of the accelerometer according to the present invention.

[0074] Figure 15 This is a schematic diagram of the structure for the negative and positive test of the accelerometer cross-axis string according to the present invention.

[0075] Among them, 1. Centrifugal transfer fixture; 2. Centrifugal testing fixture turntable; 3. Testing transfer fixture; 4. Chip testing board; 5. Fixture mechanism; 501. Y-axis fixture mechanism; 502. Y-axis fixture mechanism; 503. Fixture outer frame; 504. Tube shell groove; 505. Spring; 506. Pressure plate; 507. Pressure comb teeth; 6. Centrifuge turntable; 7. Slip ring. Detailed Implementation

[0076] The technical solutions of the MEMS accelerometer centrifugal testing structure, system, and method provided by the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0077] Example 1

[0078] like Figures 1-6As shown, a MEMS accelerometer centrifugal testing structure includes: a centrifugal adapter 1, which provides a mounting carrier for the adapter and allows the adapter to be mounted on a centrifuge; a centrifugal testing turntable 2, which is mounted on the centrifugal adapter 1 by fasteners, and its center is concentric with the center of the centrifugal adapter 1; a testing adapter 3, which is cross-shaped, and its four corners are fixedly mounted on the centrifugal testing turntable 2 by locking fasteners; a chip testing board 4, which is fixedly mounted on the testing adapter 3 by locking fasteners, and the chip testing board 4 is cross-shaped, with the horizontal axis of the chip testing board 4 defined as the X-axis and the vertical axis as the Y-axis; the chip testing board 4 is used to collect and transmit accelerometer data during testing; and multiple clamping mechanisms 5, which are used to clamp the accelerometer onto the structure; the multiple clamping mechanisms 5 are uniformly fixedly mounted on the surface of the chip testing board 4 along the X-axis and Y-axis.

[0079] Furthermore, the clamping mechanism 5 located on the X-axis of the chip test board 4 is defined as the Y-axis clamping mechanism 501; the clamping mechanism 5 located on the Y-axis of the chip test board 4 is defined as the X-axis clamping mechanism 502; the X-axis clamping mechanism 502 and the Y-axis clamping mechanism 501 have the same structure; both the X-axis clamping mechanism 502 and the Y-axis clamping mechanism 501 include: a clamping outer frame 503, which is fixedly installed on the chip test board 4; a housing groove 504, which is used to place the housing of the accelerometer in the housing groove 504; the housing groove 50 4 is located at the bottom inside the outer frame 503 of the clamp; two springs 505 are respectively installed on opposite surfaces inside the outer frame 503 of the clamp; two clamping plates 506 are respectively installed on the corresponding springs 505; two clamping combs 507 are respectively installed at opposite edges of the outer frame 503 of the clamp, the clamping combs 507 are used to clamp the upper surface of the accelerometer shell; wherein, the clamping plates 506 are pressed against the outer surface of the accelerometer shell by the elastic force of the springs 505, clamping the accelerometer inside the outer frame 503 of the clamp.

[0080] Furthermore, the short side of the clamping outer frame 503 of the X-axis clamping mechanism 502 and the long side of the clamping outer frame 503 of the Y-axis clamping mechanism 501 are both provided with test fixture pin position markers.

[0081] Specifically, firstly, the centrifugal adapter fixture 1 is precisely aligned with the output end of the centrifuge to ensure that the entire fixture can rotate stably with the centrifuge. This step provides the basic mounting carrier for the entire test structure and directly determines the stability of the subsequent rotation process. Then, the cross-shaped test adapter fixture 3 is fixed to the four corners of the centrifugal test fixture turntable 2 using locking devices such as hexagonal screws. Utilizing the symmetry of its cross-shaped structure, it provides a uniformly stressed support surface for the subsequent installation of the chip test board 4.

[0082] Next, the cross-shaped chip test board 4 is fixed to the center area of ​​the test adapter fixture 3 using locking components. The horizontal axis of the chip test board 4 is defined as the X-axis, and the vertical axis as the Y-axis, thus clarifying the installation orientation of the subsequent fixture mechanisms. According to testing requirements, multiple fixture mechanisms 5 are evenly installed on the surface of the chip test board 4 along the X-axis and Y-axis: the Y-axis fixture mechanism 501 is installed on the X-axis, and the X-axis fixture mechanism 502 is installed on the Y-axis. When clamping the accelerometer chip, the accelerometer housing is first placed into the housing groove 504 within the outer frame 503 of the fixture. The size of the housing groove 504 precisely matches the housing to ensure that the housing does not shift laterally. Subsequently, the springs 505 on both sides of the housing push the clamping plate 506, using spring force to clamp the outer surface of the housing. Simultaneously, the clamping combs 507 on the opposite edges of the outer frame 503 of the fixture adhere to the upper surface of the housing, forming a three-dimensional fixation to prevent the housing from jumping up and down during rotation. Finally, by using the test fixture pin 1 position marker on the outer frame 503 of the fixture, the circuit interface between the accelerometer pin and the chip test board 4 is calibrated to ensure precise connection between the two and prepare for data transmission.

[0083] In this embodiment, the structure generates controllable and uniform centrifugal force through centrifugal rotation, which can accurately simulate the acceleration environment that accelerometers may experience in practical applications such as high acceleration in aerospace and automotive fields. Furthermore, the acceleration value can be precisely controlled by adjusting the turntable speed, providing reliable test conditions for verifying the measurement accuracy and linearity of the accelerometer chip. With the help of the clamping mechanism design in the X and Y axes, the X and Y axis sensitive directions of the accelerometer chip can be tested separately, comprehensively evaluating the chip's acceleration response performance in different directions.

[0084] From a structural design perspective, the stable docking of the centrifugal adapter 1 with the centrifuge and the concentric calibration of the centrifugal test fixture turntable 2 effectively avoid eccentric vibrations during rotation, reducing the impact of additional interference forces on test results. The three-dimensional fixing structure of springs, clamping plates, and clamping combs ensures that the accelerometer chip will not shift or fall off during high-speed rotation, guaranteeing the safety of the testing process. The cross-shaped structure of the test adapter 3 and the cross-shaped structure of the chip test board 4 ensure uniform stress distribution throughout the structure, reducing stress concentration during rotation, extending the service life of each fixture component, and reducing testing costs. The design of multiple fixture mechanisms evenly distributed along the X and Y axes allows for simultaneous testing of multiple accelerometer chips, significantly improving testing efficiency compared to traditional single-chip testing methods, especially suitable for performance screening scenarios in mass production. The chip test board 4 directly integrates data collection and transmission functions, reducing interference from external wiring. Simultaneously, the pin position markers on test fixture 1 enable rapid and precise docking between the chip and the test board, reducing data errors caused by wiring deviations and improving the reliability of test data.

[0085] Example 2

[0086] like Figure 7 As shown, a MEMS accelerometer centrifugal testing system includes: a centrifuge turntable 6 and eight MEMS accelerometer centrifugal testing structures described in Embodiment 1 above; wherein, the eight MEMS accelerometer centrifugal testing structures are evenly distributed around the centrifuge turntable 6 as the center, on the edge of the centrifuge turntable 6; the centrifuge turntable 6 is connected to the centrifuge drive shaft, causing the centrifuge turntable 6 to rotate and generate centrifugal force; at least one slip ring 7 is provided on the centrifuge turntable 6; the data cable for connecting the chip test board 4 is electrically connected to the peripheral test and analysis system through the slip ring 7, avoiding damage to the data cable due to tangling caused by the rotation of the centrifuge turntable 6.

[0087] Specifically, firstly, the centrifuge turntable 6 is coaxially connected to the centrifuge drive shaft. A high-precision calibration tool (such as a laser alignment instrument) is used to ensure that the concentricity error between the two is controlled within the micrometer level, avoiding additional vibrations caused by eccentricity during rotation. This lays the foundation for stable centrifugal force generation later. At least one slip ring 7 is installed on the centrifuge turntable 6. The fixed end of the slip ring 7 is connected to the external test and analysis system via a data cable, while the rotating end has a reserved connection interface for the chip test board 4 in each MEMS accelerometer centrifugal test structure, ensuring stable signal transmission channels and no risk of entanglement during rotation. Following a uniform distribution principle, eight of the aforementioned MEMS accelerometer centrifugal test structures are installed at the edge of the centrifuge turntable 6. During installation, with the center of the centrifuge turntable 6 as the center, an angle measuring tool is used to ensure that the included angle between any two adjacent test structures is 45°, so that all test structures are on a circle of the same radius during rotation, ensuring that the centrifugal force borne by each structure is consistent. The assembly status of each test structure is then checked one by one. Confirm that the centrifugal adapter 1 is securely fixed to the centrifuge turntable 6, that the centrifugal test fixture turntable 2 is concentric with the centrifugal adapter 1, and that the accelerometer chip in the clamping mechanism 5 is properly clamped. At the same time, connect the data cable of each chip test board 4 to the corresponding rotating end interface of the slip ring 7 to complete the signal link construction of the entire test system.

[0088] In this embodiment, compared to a single MEMS accelerometer centrifugal test structure, this system, through a centrifuge turntable 6 and an array design of eight test structures, can simultaneously test eight groups of accelerometer chips. Taking batch testing of 100 chips as an example, the efficiency can be multiplied compared to single-structure testing, effectively meeting the performance screening requirements in the mass production of MEMS accelerometers in consumer electronics, automotive electronics, and other fields, and reducing unit testing costs. The eight test structures are evenly distributed on the centrifuge turntable 6 and are at the same rotation radius, ensuring that all test samples are subjected to completely consistent centrifugal force and environmental conditions, avoiding inter-sample testing errors caused by changes in equipment status in traditional multi-batch testing. At the same time, multi-channel synchronous data acquisition can evaluate test repeatability through statistical analysis, further improving the reliability of test results.

[0089] Example 3

[0090] like Figures 8-15 As shown, a centrifugal testing method for MEMS accelerometers is applicable to the MEMS accelerometer centrifugal testing system in Embodiment 3 above. This method performs testing and full-scale calibration of the accelerometer, obtaining indicators of zero bias and nonlinearity, and evaluating the cross-axis crosstalk of the accelerometer. The method includes:

[0091] S1. Install the accelerometer in the X-axis clamping mechanism 502 or the Y-axis clamping mechanism 501 according to the test direction of the accelerometer's sensitive axis. Step S1 is the foundation of the entire centrifugation test, and the accuracy of its operation directly determines the reliability of subsequent test data. The core objective of this step is to accurately and securely install the MEMS accelerometer in the dedicated X-axis clamping mechanism 502 and Y-axis clamping mechanism 501, ensuring that the sensitive axis direction of the accelerometer remains consistent with the centrifugal force loading direction during the test, while avoiding additional test errors introduced by installation deviations.

[0092] Furthermore, S1 includes: S101, determining whether the sensitive axis direction of the accelerometer is the X-axis or the Y-axis, and determining the position marker of pin 1 of the MEMS accelerometer chip. MEMS accelerometers typically have a specific sensitive axis direction, commonly the X-axis or the Y-axis. Technicians must accurately determine the sensitive axis direction of the accelerometer under test by observing the silkscreen markings on the chip surface, pin definitions, or using dedicated optical inspection equipment, based on the accelerometer's product specifications or design drawings, to clarify whether it is sensitive to acceleration in the X-axis or Y-axis direction. The accuracy of this step is crucial; if the sensitive axis direction is determined incorrectly, the entire subsequent testing process will be meaningless, and it may even damage the accelerometer chip due to improper force direction. Pin 1 is the reference pin for electrical connection between the MEMS accelerometer chip and the chip test board 4; determining its position is key to achieving precise docking between the chip and the tooling. Technicians can identify the position marker of pin 1 of the chip through various methods. First, observe any special markings on the chip package edge, such as missing corners, dots, or the silkscreened number "1". Second, refer to the pinout diagram in the product specification sheet and determine the location of pin 1 based on the pin arrangement. For bare chips without obvious external markings, high-precision pin inspection equipment may be needed to accurately locate pin 1 by detecting the internal circuit connections. After determining the location of pin 1, clearly mark it using a dedicated marker or in a test record table for comparison during subsequent installation.

[0093] S102. The pin 1 position marker on the chip corresponds to the pin 1 position marker on the test fixture. Specifically, after completing step S101 and identifying the pin 1 position marker on the accelerometer chip, this marker must be precisely aligned with the pin 1 position marker on the chip test board 4. This is a core step for ensuring reliable electrical signal transmission between the chip and the external test system. The chip test board 4 typically has a pin 1 position marker at a specific location corresponding to the accelerometer mounting area, designed according to standard specifications. This marker is similar in form to the pin 1 marker on the chip, and may be a silkscreen mark, a metal contact mark, or a specific pad arrangement. Technicians must gently place the accelerometer chip in the designated mounting position on the test fixture. By visual inspection or with the aid of a microscope, the placement angle and position of the chip are adjusted so that the pin 1 position marker on the chip completely coincides with the pin 1 position marker on the test fixture or is within the preset alignment tolerance range. During the alignment process, care must be taken to avoid physical damage to the chip; pressing the chip or the test fixture forcefully is prohibited. At the same time, it is necessary to check whether there are foreign objects between the chip and the test fixture. If there are foreign objects, they should be cleaned with special cleaning tools to prevent poor pin contact caused by foreign objects, which would affect subsequent electrical signal transmission and test data acquisition.

[0094] S103. The MEMS accelerometer with the X-axis sensitive axis or the MEMS accelerometer with the Y-axis sensitive axis is clamped by the X-axis clamping mechanism 502 and the Y-axis clamping mechanism 501. After the chip is accurately aligned with the pin markings of the test fixture, the accelerometer needs to be clamped and fixed by the X-axis clamping mechanism 502 and the Y-axis clamping mechanism 501 to ensure that the accelerometer remains stable throughout the centrifugation test and does not shift or shake.

[0095] Furthermore, in S103, the positive direction of the sensing axis of the MEMS accelerometer with the X-axis sensing axis clamped in the X-axis clamping mechanism 502 and the Y-axis clamping mechanism 501 is the positive direction of the X-axis of the chip test board 4; or, the positive direction of the sensing axis of the MEMS accelerometer with the Y-axis sensing axis clamped in the X-axis clamping mechanism 502 and the Y-axis clamping mechanism 501 is the negative direction of the Y-axis of the chip test board 4.

[0096] Specifically, for MEMS accelerometers whose sensitive axis has been determined to be in the X-direction, it is necessary to ensure that the positive direction of its sensitive axis is consistent with the positive X-axis direction of the chip test board 4 during clamping. Technicians should gently press the aligned accelerometer chip into its mounting position on the test fixture, and then operate the clamping assembly of the X-axis clamping mechanism 502 to apply uniform clamping force from both sides of the chip or a specific fixed position, firmly fixing the chip in the fixture. During clamping, a torque wrench or pressure sensor should be used to control the clamping force to avoid excessive clamping force that could deform the chip package, damage the pins, or damage the internal sensitive structure. At the same time, insufficient clamping force should also be prevented, which could cause chip displacement during testing. After clamping, the consistency between the positive direction of the accelerometer's sensitive axis and the positive X-axis direction of the chip test board 4 should be reconfirmed using optical inspection equipment to ensure that the deviation is within the allowable range.

[0097] Unlike X-axis accelerometers, for Y-axis MEMS accelerometers, the positive direction of its sensing axis must correspond to the negative Y-axis of the chip test board 4 during clamping. The operation procedure is similar to that of the X-axis accelerometer: technicians first place the aligned chip in the mounting position, and then clamp and fix the chip using the clamping components of the Y-axis clamping mechanism 501. During clamping, the clamping force must be strictly controlled, and after clamping, a dedicated testing tool is used to verify the correspondence between the positive direction of the accelerometer's sensing axis and the negative Y-axis of the chip test board 4 to ensure compliance with testing requirements. If the directional deviation exceeds the allowable range, the clamp must be loosened and the chip position readjusted until the alignment requirements are met before re-clamping.

[0098] In this implementation, the method can specifically perform full-scale calibration of the accelerometer chip, test core performance indicators such as zero bias and nonlinearity, and scientifically evaluate cross-axis crosstalk, covering key performance verification needs of MEMS accelerometers in R&D, production, and quality inspection. From a practical application perspective, full-scale calibration clarifies the output characteristics of the accelerometer within its maximum measurement range, ensuring its measurement accuracy under different load scenarios; obtaining the zero bias indicator helps technicians determine the output stability of the accelerometer when no external force is applied, avoiding excessive zero drift from affecting measurement results in practical applications; nonlinearity testing quantifies the deviation in the linear relationship between the accelerometer output and input acceleration, providing a basis for subsequent data calibration. The evaluation of cross-axis crosstalk is crucial for multi-axis collaborative scenarios, enabling early detection of signal interference between different sensitive axes and ensuring measurement accuracy under complex motion conditions. This feature of simultaneous testing of multiple indicators eliminates the need for repeated operations using multiple testing methods, significantly improving testing efficiency and reducing testing costs.

[0099] After completing the precise installation of the MEMS accelerometer (S1 step), the testing process enters the core performance data acquisition stage, namely the S2 positive test and the S3 negative test. These two steps simulate the working state of the accelerometer under positive and negative loads by precisely controlling the directional rotation of the centrifugal testing fixture turntable and the centrifuge speed, thereby achieving a comprehensive capture of its output characteristics and providing key data support for subsequent full-scale calibration, zero-bias calculation, and other processes.

[0100] like Figure 8 and Figure 10 As shown, S2, the accelerometer is tested in the forward direction. By rotating the centrifugal test fixture turntable 2, the sensitive axis of the accelerometer is uniformly opposite to the center of the centrifuge turntable 6. The centrifugal test fixture turntable 2 is fixed on the centrifuge turntable 6 by a fixing component. The centrifuge is turned on and the centrifuge speed is controlled to apply a preset centripetal acceleration to the accelerometer. The forward test points are selected according to the preset interval to perform a stepped forward test.

[0101] Furthermore, in S2, the formula for calculating the preset centripetal acceleration 'a' applied to the accelerometer is:

[0102] (Equation 1)

[0103] in This refers to the rotational speed of the centrifuge turntable. This is the distance between the center of the accelerometer and the centrifuge turntable.

[0104] Specifically, the core objective of the S2 forward test is to simulate the working scenario of the accelerometer under forward load on the sensitive axis. By applying a stepped centripetal acceleration from low to high, the output signal of the accelerometer under different loads is collected to obtain its performance data within the forward measurement range.

[0105] Before starting the centrifuge, the centrifuge testing fixture turntable 2 must first be rotated in an orientation manner. The goal is to ensure that the sensitive axes of the accelerometers installed in the X-axis clamping mechanism 502 or Y-axis clamping mechanism 501 are aligned so that their positive directions are opposite to the center of the centrifuge turntable 6. Essentially, this operation aligns the direction of the centrifugal force with the positive direction of the accelerometer's sensitive axis. When the centrifuge rotates, the direction of centripetal acceleration points towards the center, while the direction of the effective load sensed by the accelerometer is opposite to the centripetal acceleration (i.e., away from the center), coinciding precisely with the positive direction of the sensitive axis. This ensures that the load is accurately applied to the sensitive axis, avoiding data distortion caused by directional deviation.

[0106] During the rotation of the turntable, technicians need to use the scale markings or optical positioning equipment on the tooling turntable for auxiliary calibration to ensure that the positive orientation of the sensitive axes of all accelerometers installed on the tooling meets the requirement of being away from the center. If the orientation accuracy of the turntable is insufficient, it may cause the actual force direction of some accelerometers to be at an angle to the preset positive direction, resulting in the collected output signal containing interference from lateral loads and affecting the accuracy of subsequent data.

[0107] After fixing, the centrifuge system is turned on, entering the speed control stage. Technicians need to adjust the speed of the centrifuge turntable 6 through the centrifuge's host computer control system according to the preset centripetal acceleration target value. Because the magnitude of centripetal acceleration is proportional to the square of the rotational speed, even small fluctuations in rotational speed will cause significant changes in the acceleration load. Therefore, by precisely controlling the rotational speed, precise control of the centripetal acceleration applied by the accelerometer can be indirectly achieved.

[0108] During the increase in rotational speed, a gradual increase must be followed to avoid sudden shock loads on the accelerometer caused by a sudden increase in speed. Simultaneously, the centrifuge control system must monitor the speed feedback signal in real time. If speed fluctuations exceed the allowable range, the speed compensation mechanism must be automatically triggered to ensure the stability of centripetal acceleration.

[0109] Once the centrifuge speed stabilizes at the first preset value, the stepped forward testing phase begins. Technicians must select forward test points at preset intervals, collecting data sequentially from low load to high load. The intervals here need to be determined based on the accelerometer's full-scale range and the required testing accuracy. If the full-scale range is ±500g and the required test point interval is 50g, then 10 forward test points need to be set, i.e., 0g, 50g, 100g…500g, where 0g is the zero-bias test point, and 1g is approximately… .

[0110] At each test point, the rotational speed must be kept stable. The specific stabilization time can be determined based on the accelerometer's response time. After the accelerometer output signal stabilizes, multiple sets of output data are continuously collected through the data acquisition system. The average value of the data is then calculated to eliminate random noise interference. After data acquisition, the rotational speed is increased at preset intervals to proceed to the next test point, until data acquisition for all forward test points is completed. Throughout the entire stepped test process, key parameters such as rotational speed, centripetal acceleration, and average output signal value must be recorded to generate a complete forward test data report.

[0111] like Figure 9 and Figure 11 As shown in Figure S3, after completing the positive test, a negative test is performed on the accelerometer. Without disassembling the accelerometer, the centrifugal test fixture turntable 2 is rotated so that the positive direction of the accelerometer's sensitive axis is uniformly pointed to the center of the centrifuge turntable 6. The centrifugal test fixture turntable 2 is fixed on the centrifuge turntable 6 by a fastener. The centrifuge is turned on and the centrifuge speed is controlled to apply a preset centripetal acceleration to the accelerometer. Negative test points are selected according to the preset interval to perform a stepped negative test.

[0112] Furthermore, in S3, the formula for calculating the preset centripetal acceleration 'a' applied to the accelerometer is:

[0113] (Equation 1)

[0114] in This refers to the rotational speed of the centrifuge turntable. This is the distance between the center of the accelerometer and the centrifuge turntable.

[0115] Specifically, the S3 negative test complements the positive test. Its core objective is to simulate the accelerometer's operating scenario under negative load on the sensitive axis, forming a full-range coverage with step S2 to ensure the capture of the accelerometer's output characteristics during positive load switching. The key advantage of this step is that it avoids disassembling the accelerometer, preventing positional deviations caused by secondary installation, and significantly improving the accuracy of comparing positive and negative test data.

[0116] After completing the S2 forward test, without disassembling the accelerometer, directly rotate the centrifuge test fixture turntable 2 in the reverse direction. The goal is to align the positive direction of the accelerometer's sensing axis with the center of the centrifuge turntable 6. At this point, when the centrifuge rotates, the direction of centripetal acceleration is completely consistent with the positive direction of the accelerometer's sensing axis, and the load acts directly on the negative direction of the sensing axis.

[0117] The precision control requirements during the turntable rotation process are the same as in S2, ensuring that the positive direction of the sensing axis of all accelerometers is precisely aligned with the center. Since there is no need to disassemble the chip, the rotation reference of the turntable can directly use the positioning marks in S2. Orientation can be quickly completed with the assistance of the reverse scale on the tooling turntable or optical equipment, reducing operation time and avoiding problems such as poor pin contact and sensing axis misalignment that may be introduced by secondary installation.

[0118] Similar to step S2, after orienting the turntable, the centrifuge testing fixture turntable 2 must be secured to the centrifuge turntable 6 again using the fasteners. Special attention must be paid here: the tightening torque of the fasteners must be consistent with that in S2 to avoid slight changes in the position of the fixture turntable due to torque differences, which could affect the comparability of positive and negative test data. After securing, the coaxiality and flatness of the fixture turntable must also be checked to ensure that the test conditions are consistent with S2.

[0119] In the speed control stage, the preset centripetal acceleration values ​​of S3 are symmetrically distributed with those of S2. For example, if the positive test points of S2 are 50g, 100g...500g, then the negative test points of S3 must be set to -50g, -100g...-500g. Control parameters such as speed increase rate and settling time are completely consistent with S2 to ensure environmental consistency in both positive and negative tests, avoiding errors caused by differences in test conditions, and providing reliable comparative data for subsequent calculations of nonlinearity, hysteresis error, and other indicators.

[0120] The method also includes: S4, acquiring the velocity output from the accelerometer at each positive and negative test point via the chip test board 4. The data is then transmitted to the peripheral testing and analysis system to calculate the nonlinearity of the accelerometer. .

[0121] Furthermore, S4 includes:

[0122] S401. Process the accelerometer output velocities at each positive and negative test point, and obtain the linear equation:

[0123] (Equation 2)

[0124] in, This represents the theoretical output value of the accelerometer under different accelerations. To obtain the scale factor across the entire accelerometer range, To determine the zero bias of the accelerometer at 0g, 1g is approximately... .

[0125] S402, Calculated using the least squares method and Its formula is:

[0126] (Equation 3)

[0127] (Equation 4)

[0128] in, The accelerometer output value at a certain acceleration. For the corresponding accelerometer value, This represents the total number of accelerometers. The least squares method is used for calculation. and Compared to the simple two-point method (such as calculating K by taking two points, one on the positive end of the full scale and one on the negative end of the full scale), this method has significant advantages. It can integrate information from all test points, rather than relying solely on two endpoints, thus making the calculated K more accurate. and This better reflects the average characteristics of the accelerometer across its entire range. Secondly, by minimizing the sum of squared errors, it ensures that the overall deviation between the fitted linear model and the actual data is minimized, providing the most accurate theoretical reference for subsequent nonlinearity calculations.

[0129] S403. Compare the output velocity of each accelerometer at each positive and negative test point with the corresponding theoretical value of the accelerometer. The difference between them yields the maximum residual of the accelerometer. Maximum residual It is one of the key indicators for measuring the nonlinearity of accelerometers. The larger the value, the more significant the deviation between the actual output of the accelerometer and the linear model, and the higher the nonlinearity.

[0130] S404. Calculate the nonlinearity of the accelerometer. :

[0131] (Equation 5)

[0132] in, This is the theoretical maximum output value of the accelerometer. This is the theoretical minimum output value of the accelerometer.

[0133] Specifically, nonlinearity It is a dimensionless proportionality value that reflects the proportion of the maximum deviation of the actual output of the accelerometer from the linear model to the theoretical output range. For example, if =0.01 indicates that the accelerometer's maximum output deviation is 1% of the theoretical output range, indicating good linearity; if A value of 0.05 indicates poor linearity, which may not meet the requirements in high-precision applications. Through a series of operations in step S4, from data acquisition and linear fitting to residual statistics and nonlinearity calculation, a complete and accurate assessment of the nonlinearity of MEMS accelerometers is achieved, providing crucial quantitative basis for accelerometer performance optimization, quality inspection, and application adaptation.

[0134] like Figures 12-15 As shown in step S5, the accelerometer is mounted on a chip fixture orthogonal to its sensitive axis. By rotating the centrifugal test fixture turntable 2, the non-sensitive axis direction of the accelerometer is aligned with the center of the centrifuge turntable 6. The centrifuge is turned on and its speed is controlled. When the accelerometer is subjected to acceleration in the non-sensitive axis direction, the output value in the sensitive axis direction is obtained. and output values An assessment will be conducted.

[0135] Furthermore, S5 includes:

[0136] The evaluation value of the cross-axis crosstalk of the accelerometer is calculated using the following formula:

[0137] (Equation 6)

[0138] in, This represents the output value along the sensitive axis when the input is at full scale.

[0139] Specifically, A smaller value indicates weaker cross-axis crosstalk, and a stronger anti-interference capability of the accelerometer under multi-axis loading. However, different application scenarios have different requirements for cross-axis crosstalk; for example, high-precision inertial navigation systems typically require… ≤0.1%, while the consumer electronics sector may allow ≤5%. By calculating the S-axis crosstalk, it can be determined whether the accelerometer meets the requirements of the target application scenario. Through the detailed operation of step S5 and the calculation of the crosstalk evaluation value, the degree of crosstalk in the sensitive axis direction of the MEMS accelerometer when the non-sensitive axis is loaded can be accurately quantified. This provides a key basis for accelerometer performance optimization, quality control and application scenario selection, ensuring its measurement accuracy in multi-axis complex stress environments.

[0140] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A centrifugal testing structure for a MEMS accelerometer, characterized in that, The structure includes: Centrifugal adapter (1), which provides a mounting carrier for the adapter and allows the adapter to be mounted on a centrifuge; The centrifugal test fixture turntable (2) is mounted on the centrifugal transfer fixture (1) by means of a fastener, and its center is concentric with the center of the centrifugal transfer fixture (1); Test adapter (3): The test adapter (3) is cross-shaped, and the four corners of the test adapter (3) are fixedly installed on the centrifugal test fixture turntable (2) by locking parts; Chip test board (4); The chip test board (4) is fixedly installed on the test adapter fixture (3) by locking parts. The chip test board (4) is cross-shaped. The horizontal axis of the chip test board (4) is defined as the X-axis and the vertical axis of the chip test board (4) is defined as the Y-axis. The chip test board (4) is used to collect and transmit accelerometer data during testing. Multiple clamping mechanisms (5) are used to clamp the accelerometer onto the structure; the multiple clamping mechanisms (5) are uniformly fixedly mounted on the surface of the chip test board (4) along the X and Y axes of the chip test board (4).

2. The MEMS accelerometer centrifugal testing structure according to claim 1, characterized in that, The clamping mechanism (5) located on the X-axis of the chip test board (4) is defined as the Y-axis clamping mechanism (501); the clamping mechanism (5) located on the Y-axis of the chip test board (4) is defined as the X-axis clamping mechanism (502); the X-axis clamping mechanism (502) and the Y-axis clamping mechanism (501) have the same structure; Both the X-axis clamping mechanism (502) and the Y-axis clamping mechanism (501) include: The outer frame of the fixture (503) is fixedly mounted on the chip test board (4); The housing groove (504) is used to place the housing of the accelerometer in the housing groove (504); the housing groove (504) is opened at the bottom inside the outer frame (503) of the fixture; Two springs (505) are respectively mounted on opposite surfaces inside the outer frame (503) of the clamp; Two clamping plates (506) are respectively mounted on corresponding springs (505); Two clamping combs (507) are respectively installed at opposite edges of the outer frame (503) of the clamp, the clamping combs (507) being used to clamp the upper surface of the accelerometer housing; The clamping plate (506) presses against the outer surface of the accelerometer housing by the elastic force of the spring (505), clamping the accelerometer inside the outer frame (503) of the fixture.

3. The MEMS accelerometer centrifugal testing structure according to claim 2, characterized in that, The X-axis clamping mechanism (502) has a clamping outer frame (503) with a short side, and the Y-axis clamping mechanism (501) has a clamping outer frame (503) with a long side with a test fixture pin 1 position mark.

4. A MEMS accelerometer centrifugation testing system, characterized in that, The system includes: a centrifuge turntable (6) and eight MEMS accelerometer centrifugation test structures as described in any one of claims 1-3; Among them, the eight MEMS accelerometer centrifugal test structures are evenly distributed on the edge of the centrifuge turntable (6) with the centrifuge turntable (6) as the center; The centrifuge turntable (6) is connected to the centrifuge drive shaft, which causes the centrifuge turntable (6) to rotate and generate centrifugal force; The centrifuge turntable (6) is provided with at least one slip ring (7); the data cable for connecting the chip test board (4) is connected to the electrical performance of the peripheral test and analysis system through the slip ring (7) to avoid the data cable being damaged by tangling due to the rotation of the centrifuge turntable (6).

5. A centrifugal testing method for MEMS accelerometers, characterized in that, This method is applicable to the MEMS accelerometer centrifugal testing system described in claim 4, for testing and full-scale calibration of the accelerometer, obtaining indicators of zero bias and nonlinearity, and evaluating the cross-axis crosstalk of the accelerometer; the method includes: S1. According to the direction of the accelerometer's sensitive axis, install it in the corresponding X-axis clamping mechanism (502) or Y-axis clamping mechanism (501); S2. Perform a forward test on the accelerometer. By rotating the centrifugal test fixture turntable (2), make the sensitive axis of the accelerometer uniformly move away from the center of the centrifuge turntable (6). The centrifugal test fixture turntable (2) is fixed on the centrifuge turntable (6) by a fastener. Turn on the centrifuge and control the centrifuge speed to apply a preset centripetal acceleration to the accelerometer. Select forward test points according to the preset interval and perform a stepped forward test. S3. After completing the positive test, perform a negative test on the accelerometer. Without disassembling the accelerometer, rotate the centrifugal test fixture turntable (2) so that the positive direction of the accelerometer's sensitive axis is uniformly pointed to the center of the centrifugal turntable (6). The centrifugal test fixture turntable (2) is fixed on the centrifugal turntable (6) by a fastener. Turn on the centrifuge and control the centrifuge speed to apply a preset centripetal acceleration to the accelerometer. Select negative test points according to the preset interval and perform a stepped negative test. S4. The accelerometer output speed of each positive and negative test point is collected through the chip test board (4). The data is then transmitted to the peripheral testing and analysis system to calculate the nonlinearity of the accelerometer. ; S5. Install the accelerometer on a chip fixture orthogonal to its sensitive axis direction. Rotate the centrifugal test fixture turntable (2) so that the non-sensitive axis direction of the accelerometer points to the center of the centrifuge turntable (6). Turn on the centrifuge and control the centrifuge speed. When the non-sensitive axis direction is subjected to acceleration, obtain the output value in the sensitive axis direction. and output values An assessment will be conducted.

6. The MEMS accelerometer centrifugation test method according to claim 5, characterized in that, S1 includes: S101. Determine whether the sensitive axis direction of the accelerometer is the X-axis or the Y-axis, and determine the position marker of pin 1 of the MEMS accelerometer chip. S102, the position marker of pin 1 of the chip corresponds to the position marker of pin 1 of the test fixture; S103, The MEMS accelerometer with the sensitive axis of the X direction or the MEMS accelerometer with the sensitive axis of the Y direction is clamped by the X-axis clamping mechanism (502) and the Y-axis clamping mechanism (501).

7. The MEMS accelerometer centrifugation test method according to claim 6, characterized in that, In S103, the positive direction of the sensitive axis of the MEMS accelerometer with the X-direction sensitive axis clamped in the X-axis clamping mechanism (502) and the Y-axis clamping mechanism (501) is the positive direction of the X-axis of the chip test board (4); Alternatively, the positive direction of the sensitive axis of the MEMS accelerometer with the Y-direction sensitive axis clamped in the X-axis clamping mechanism (502) and the Y-axis clamping mechanism (501) is the negative direction of the Y-axis of the chip test board (4).

8. The MEMS accelerometer centrifugation test method according to claim 7, characterized in that, In S2 and S3, the formula for calculating the preset centripetal acceleration 'a' applied to the accelerometer is: (Equation 1) in, This refers to the rotational speed of the centrifuge turntable. This is the distance between the center of the accelerometer and the centrifuge turntable.

9. The MEMS accelerometer centrifugation test method according to claim 8, characterized in that, S4 includes: S401. Process the accelerometer output velocities at each positive and negative test point, and obtain the linear equation: (Equation 2) in, This represents the theoretical output value of the accelerometer under the corresponding acceleration. To obtain the scale factor across the entire accelerometer range, To determine the zero bias of the accelerometer at 0g, 1g is approximately... ; S402, Calculated using the least squares method and Its formula is: (Equation 3) (Equation 4) in, The accelerometer output value at a certain acceleration. For the corresponding accelerometer value, This represents the total number of accelerometers. S403. Compare the output velocity of each accelerometer at each positive and negative test point with the theoretical value. The difference between them yields the maximum residual of the accelerometer. ; S404. Calculate the nonlinearity of the accelerometer. ; (Equation 5) in, This is the theoretical maximum output value of the accelerometer. This is the theoretical minimum output value of the accelerometer.

10. The MEMS accelerometer centrifugation test method according to claim 8, characterized in that, S5 includes: The evaluation value of the cross-axis crosstalk of the accelerometer is calculated using the following formula: (Equation 6) in, This represents the output value along the sensitive axis when the input is at full scale.

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