MEMS accelerometer scale factor batch test device and method

Abstract

The invention provides an MEMS accelerometer scale factor batch test device and method, the device comprises a centrifugal machine and a plurality of test tools, the centrifugal machine is provided with a centrifugal machine disc, the plurality of test tools are uniformly arranged on the disc surface at intervals along the circumferential direction of the centrifugal machine disc, every two symmetrical test tools form a group, and the centrifugal machine disc is provided with a centrifugal machine disc. The test tool comprises a fixed bottom plate, two test circuit switching tools, an accelerometer fixing device and a test circuit board, the fixed bottom plate is fixedly arranged on the disc, the two test circuit switching tools are symmetrically fixed on the fixed bottom plate at intervals, the test circuit board is fixedly arranged on the two switching tools, and the accelerometer fixing device is fixed on the test circuit board. The accelerometer is arranged on the test circuit board through the accelerometer fixing device and is electrically connected with the test circuit board. According to the invention, the scale factor symmetry test of a plurality of accelerometers is completed at the same time by using a specific batch test tool and a calculation method.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon micro-electromechanical system accelerometer scale factor symmetry measurement, and specifically to a MEMS accelerometer scale factor batch testing device and method, specifically a test method for batch testing of accelerometer scale factor symmetry by performing centrifugal tests through batch fixture test circuits and adopting batch processing algorithms. Background Art

[0002] The development of a new generation of weapons and the upgrade of existing weapons have made the demand for miniaturized, low-power accelerometers more urgent. Silicon micro-electromechanical accelerometers are widely used in navigation systems due to their high sensitivity, small temperature drift, good damping characteristics, and high integration. They are currently the best choice for miniaturization of weapon systems.

[0003] In order to verify the accuracy of the scale factor of silicon micro-electromechanical accelerometers in different sensitive directions, it is usually necessary to perform a scale factor symmetry test on them. The scale factor symmetry test is completed by centrifugal test. In the centrifuge test, the IEEE model, method and data processing method are used. The accelerometer needs to be installed on the centrifuge (accuracy 10-5) through a special tooling, so that the sensitive axis is parallel to the axis of centrifugal acceleration, and the accelerometer needs to be installed in the positive and negative directions respectively to measure the scale factor symmetry in two directions. During the test, the tooling needs to be disassembled to adjust the test direction. In order to ensure the test accuracy, the static radius needs to be measured before each test. This method can only test one accelerometer in a single test, and the test efficiency is low. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0005] To this end, the present invention provides a MEMS accelerometer scale factor batch testing device and method, which can simultaneously complete the scale factor symmetry test of multiple accelerometers by using specific batch testing tooling and calculation methods.

[0006] The technical solution of the present invention is as follows:

[0007] According to one aspect, a batch test device for scale factor of MEMS accelerometers is provided, the device comprising: a centrifuge and a plurality of test fixtures, the centrifuge having a centrifuge disc, the plurality of test fixtures being evenly spaced on the surface of the centrifuge disc along the circumference thereof, wherein every two symmetrical test fixtures form a group, the test fixtures comprising: a fixed base plate, a test circuit adapter fixture, an accelerometer fixture and a test circuit board, the fixed base plate being fixedly arranged on the disc, the number of the test circuit adapter fixtures being two, symmetrically spaced and fixed on the fixed base plate, the test circuit board being fixedly arranged on the two adapter fixtures, the accelerometer being arranged on the test circuit board via the accelerometer fixture, the accelerometer being electrically connected to the test circuit board via the accelerometer fixture, for any group of test fixtures, the two test circuit boards being respectively designed as a positive test board and a negative test board, so that the accelerometer can be installed on the corresponding test board and acceleration values ​​in different directions can be input to the accelerometer; all adjacent accelerometer fixtures can be connected to form a ring, the center of the ring coincides with the center of the centrifuge disc.

[0008] Furthermore, the test cable in the centrifuge is also connected to the test circuit, and outputs a signal to the test machine through the centrifuge slip ring.

[0009] Furthermore, the transfer tooling has a hollow portion, which is located below the test circuit board and is used to prevent the circuit elements from directly contacting the transfer tooling and causing a short circuit.

[0010] Furthermore, the number of the test fixtures is an even number, at least 4.

[0011] Furthermore, the accelerometer fixing device includes a base, a probe structure and an upper cover, wherein the base is fixed on a circuit board and has a positioning groove, wherein the accelerometer is placed in the positioning groove in a fixed installation direction, and the upper cover presses the accelerometer downward to push out the probe structure, wherein the top of the probe structure contacts the accelerometer tube leg, and the bottom of the probe structure contacts the circuit board pad, thereby realizing electrical connection between the circuit board and the accelerometer.

[0012] Furthermore, the accelerometer data measured during the centrifugation process is corrected by the following method:

[0013] After the accelerometer is installed, input 1g acceleration to it, measure the output value at this time, and divide it by the actual scale factor of the accelerometer to obtain the proportional coefficient K;

[0014] The data measured during the centrifugation process are multiplied by this coefficient to calculate a new output value, and the scale factor symmetry value after excluding the installation error is calculated through this output value.

[0015] Furthermore, the material of the fixed base plate is aluminum, and a protective layer is formed on its surface by passivation to insulate it from other components.

[0016] Furthermore, the test circuit transfer tooling is made of aluminum, and a protective layer is formed on its surface by passivation, thereby isolating the tooling from the batch test circuit board.

[0017] According to another aspect, a method for batch testing of MEMS accelerometer scale factors is provided. The method is based on the above-mentioned device and specifically includes:

[0018] Install the above-mentioned devices;

[0019] After the device is installed, collect the accelerometer output data, including:

[0020] First, the accelerometer is installed in the positive acceleration input test circuit, and the corresponding acceleration is input according to the test requirements. At the same time, the accelerometer output value is collected through the acquisition system. Then, the accelerometer is installed in the negative acceleration input test circuit to complete the negative acceleration value data collection;

[0021] Process the acquired data and calculate the accelerometer scale factor symmetry:

[0022] Install the accelerometer on the test circuit board, input 1g acceleration to it, measure the output value at this time, and divide it with the actual scale factor to obtain the proportional coefficient K;

[0023] The data measured during the centrifugation process are multiplied by this coefficient to calculate a new output value, and the scale factor symmetry value after excluding the installation error is calculated through this output value.

[0024] The above technical solution solves the problem that multiple products cannot be tested simultaneously during the measurement of the scale factor symmetry of silicon micro-electromechanical accelerometers. Through the normalization idea, the scale factor symmetry of the accelerometers tested in batches can be approximately calculated within a certain error range, which reduces the test steps and greatly improves the test efficiency. Specifically:

[0025] 1) The present invention adopts modular design thinking and utilizes an adapter base to transfer and install different types of test circuit boards, thereby improving the compatibility of the test system;

[0026] 2) The present invention uses a special fixture to fix and install the accelerometer during the test process, which greatly shortens the time for replacing the accelerometer and improves the test efficiency;

[0027] 3) The present invention adopts a method of matching a positive acceleration input test circuit with a negative acceleration input test circuit, and symmetrically installs the batch test circuits at both ends of the centrifuge, which can conveniently complete the acceleration input in different directions and eliminate the disassembly link of the test tooling;

[0028] 4) The present invention uses a specific algorithm to normalize the output value of the accelerometer, and uses the normalization method to accurately calculate the actual centrifugal radius of each accelerometer, eliminate the installation error, and use the centrifugal test circuits in different directions to simultaneously complete the nonlinear test of the scale factor in two directions. That is, the specific algorithm of the present invention can eliminate the influence of the installation radius error on the scale factor symmetry test, and can complete the test and calculation of the symmetry of the scale factor of the accelerometer in batches. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The included drawings are used to provide a further understanding of the embodiments of the present invention, which constitute a part of the specification, are used to illustrate the embodiments of the present invention, and together with the text description, explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 It is a structural diagram of the fixed base plate;

[0031] Figure 2 It is the structural diagram of batch test circuit transfer tooling;

[0032] Figure 3 It is a schematic diagram of batch test circuit;

[0033] Figure 4 It is a schematic diagram of the batch test device for the symmetry of the accelerometer scale factor. DETAILED DESCRIPTION

[0034] It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0036] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0037] like Figure 1-4 As shown, in one embodiment of the present invention, a MEMS accelerometer scale factor batch testing device is provided, the device comprising: a centrifuge and a plurality of test fixtures, the centrifuge having a centrifuge disc, the plurality of test fixtures being evenly spaced along the circumference of the centrifuge disc on the disc surface, wherein every two symmetrical test fixtures form a group, the test fixtures comprising: a fixed base plate, a test circuit adapter fixture, an accelerometer fixing device and a test circuit board, the fixed base plate being fixedly arranged on the disc, the test circuit adapter fixtures being two, symmetrically spaced and fixed on the fixed base plate, The test circuit board is fixedly set on two transfer fixtures, and the accelerometer is set on the test circuit board through an accelerometer fixing device and is electrically connected to the test circuit board. For any set of test fixtures, the two test circuit boards are respectively designed as a positive test board and a negative test board, so that the accelerometer can be installed on the corresponding test board to input acceleration values ​​in different directions to the accelerometer; the test cable in the centrifuge is also connected to the test circuit, and the signal is output to the test machine through the centrifuge slip ring. All adjacent accelerometer fixing devices can be connected to form a ring, and the center of the ring coincides with the center of the centrifuge disk.

[0038] Preferably, the transfer tool has a hollow portion, which is located below the test circuit board to prevent the circuit element from directly contacting the transfer tool and causing a short circuit.

[0039] Preferably, the number of the test fixtures is an even number, at least 4.

[0040] In the above embodiment, the accelerometer fixture is fixed on a batch test circuit board, and its built-in probe structure is used for electrical connection between the accelerometer and the test circuit. Its upper cover is designed with screw holes for locking the accelerometer in the fixture.

[0041] Specifically, the fixing device is a clamp, which includes a base, a probe structure (i.e., a spring pin) and an upper cover. The base is fixed on the circuit board, and can be positioned at the corresponding position of the circuit board by a positioning pin. The bottom is fastened with an M2 screw. The base has a positioning groove, and the accelerometer is placed in the positioning groove in a fixed installation direction. The upper cover presses the accelerometer downward to push out the probe structure. The top of the probe structure contacts the accelerometer tube leg, and the bottom of the probe structure contacts the circuit board pad, thereby realizing the connection between the circuit board and the accelerometer.

[0042] In the above embodiment, the accelerometer data measured during the centrifugation process is corrected by the following method:

[0043] After the accelerometer is installed, input 1g acceleration to it, measure the output value at this time, and divide it by the actual scale factor of the accelerometer to obtain the proportional coefficient K;

[0044] The data measured during the centrifugation process are multiplied by this coefficient to calculate a new output value, and the scale factor symmetry value after excluding the installation error is calculated through this output value.

[0045] That is, the scale factor normalization calculation method as described above, wherein: the algorithm application scenario is scale factor symmetry processing, the algorithm estimates the actual scale through the initial scale of the accelerometer, calculates the high speed scale using the low speed scale, removes the installation error through the normalization method, and finally calculates the scale factor symmetry.

[0046] Preferably, the fixed base plate is made of aluminum, a protective layer is formed on its surface by passivation to insulate it from other components, and it is fixed to the centrifuge by screws to ensure connection with the centrifuge.

[0047] Preferably, the test circuit transfer tooling is made of aluminum, and a protective layer is formed on its surface by passivation, thereby isolating the tooling from the batch test circuit board.

[0048] According to another aspect, a method for batch testing of MEMS accelerometer scale factors is provided. The method is based on the above-mentioned device and specifically includes:

[0049] Step 1: Install the above device;

[0050] Step 2: After the device is installed, collect the accelerometer output data, including:

[0051] First, the accelerometer is installed in the positive acceleration input test circuit, and the corresponding acceleration is input according to the test requirements. At the same time, the accelerometer output value is collected through the acquisition system. Then, the accelerometer is installed in the negative acceleration input test circuit to complete the negative acceleration value data collection;

[0052] Step 3: Process the collected data and calculate the symmetry of the accelerometer scale factor:

[0053] Install the accelerometer on the centrifugal device, input 1g acceleration into it, measure the output value at this time, and divide it with the actual scale factor K1 to obtain the proportional coefficient K;

[0054] The data measured during the centrifugation process are multiplied by this coefficient to calculate a new output value, and the scale factor symmetry value after excluding the installation error is calculated through this output value.

[0055] Specifically:

[0056] The scale factor of the accelerometer is known to be K1. When 1g acceleration is input to the accelerometer, the output of the accelerometer is U 1g , the theoretical radius of the centrifuge is R, the actual installation radius of the accelerometer is r, the speed of the centrifuge is ω, calculate the theoretical input U of the accelerometer in The actual output U 1g Relationship:

[0057]

[0058] Since the input is 1g acceleration, the theoretical input U in Equal to the scale factor K1, from which the actual installation radius of the accelerometer can be obtained:

[0059]

[0060] The actual input acceleration U of the accelerometer can be obtained from this a With the theoretical acceleration U R The relationship between:

[0061]

[0062] The scale factor nonlinearity and symmetry are calculated by fitting the actual input acceleration and the accelerometer output using the least squares method.

[0063] It can be seen that the above embodiments of the present invention solve the problem that multiple products cannot be tested simultaneously during the measurement of the scale factor symmetry of the silicon micro-electromechanical accelerometer. Through the normalization concept, the scale factor symmetry of the accelerometers tested in batches can be approximately calculated within a certain error range, thereby reducing the test steps and greatly improving the test efficiency. Specifically:

[0064] 1) The present invention adopts modular design thinking and utilizes an adapter base to transfer and install different types of test circuit boards, thereby improving the compatibility of the test system;

[0065] 2) The present invention uses a special fixture to fix and install the accelerometer during the test process, which greatly shortens the time for replacing the accelerometer and improves the test efficiency;

[0066] 3) The present invention adopts a method of matching a positive acceleration input test circuit with a negative acceleration input test circuit, and symmetrically installs the batch test circuits at both ends of the centrifuge, which can conveniently complete the acceleration input in different directions and eliminate the disassembly link of the test tooling;

[0067] 4) The present invention normalizes the accelerometer output value through a specific algorithm, thereby eliminating the influence of the installation radius error on the scale factor symmetry test, and can complete the test and calculation of the accelerometer scale factor symmetry in batches.

[0068] The following is a detailed introduction to a batch testing device and method for the symmetry of the scale factor of a MEMS accelerometer of the present invention:

[0069] Figure 1 It is a structural diagram of a fixed bottom plate, which includes bottom plate and centrifuge mounting holes 1-6, and adapter tooling mounting holes 7-10.

[0070] Figure 2 It is a structural diagram of a batch test circuit transfer tooling, including tooling installation holes 11, 12, and test circuit board fixing holes 13-16. The hole diameter is Ф3.2mm and is used for installation with batch test circuit boards. The tooling hollow part 17 is located below the circuit board installation to prevent circuit components from directly contacting the tooling and causing a short circuit.

[0071] Figure 3 It is a schematic diagram of batch test circuit boards, including fixed mounting holes, pin holes and mounting screw holes for positioning special test fixtures. When in use, the special test fixture is fixed in the corresponding position and locked with M2 screws.

[0072] The specific steps of a batch testing method for the symmetry of the scale factor of a MEMS accelerometer according to an embodiment of the present invention are as follows:

[0073] The first step is to install the transfer tooling and batch test circuit board. First, fasten the transfer tooling fixed base plate to the centrifuge disc with screws, then fix the two batch test circuit transfer tooling on the fixed base plate through holes 7, 8 and holes 9, 10 respectively, and finally install the batch test circuit on the transfer tooling and connect it to the external acquisition system through the test cable in the centrifuge;

[0074] The second step is to collect accelerometer output data

[0075] First, the accelerometer is installed in the positive acceleration input test circuit, and the corresponding acceleration is input according to the test requirements. At the same time, the accelerometer output value is collected through the acquisition system. Then, the accelerometer is installed in the negative acceleration input test circuit to complete the negative acceleration value data collection;

[0076] The third step is to process the collected data and calculate the symmetry of the accelerometer scale factor.

[0077] Install the accelerometer on the centrifugal device, input 1g acceleration, measure the output value at this time, divide it by the actual scale factor to get the proportional coefficient K, which is the measurement error caused by the installation radius error;

[0078] The data measured during the centrifugation process are multiplied by this coefficient to calculate a new output value, and the scale factor symmetry value after excluding the installation error can be calculated through this output value.

[0079] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0080] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A MEMS accelerometer scale factor batch test device, characterized in that: The device comprises: a centrifuge and a plurality of test fixtures, wherein the centrifuge has a centrifuge disc, and the plurality of test fixtures are evenly spaced on the surface of the disc along the circumference of the centrifuge disc, wherein every two symmetrical test fixtures form a group, and the test fixtures comprise: a fixed base plate, a test circuit switching fixture, an accelerometer fixture and a test circuit board, wherein the fixed base plate is fixedly arranged on the disc, the test circuit board is fixedly arranged on the two switching fixtures with symmetrical intervals, the accelerometer is arranged on the test circuit board through the accelerometer fixture, and the accelerometer is electrically connected to the test circuit board through the accelerometer fixture, and for any group of test fixtures, the two test circuit boards are respectively designed as a positive test board and a negative test board, so that the accelerometer can be installed on the corresponding test board to input acceleration values ​​of different directions to the accelerometer; all adjacent accelerometer fixtures can be connected to form a ring, and the center of the ring coincides with the center of the centrifuge disc.

2. A MEMS accelerometer scale factor batch testing device according to claim 1, characterized in that: The test cable in the centrifuge is also connected to the test circuit and outputs signals to the test machine through the centrifuge slip ring.

3. The MEMS accelerometer scale factor batch testing device according to claim 1, characterized in that: The transfer tool has a hollow portion, which is located below the test circuit board and is used to prevent the circuit element from directly contacting the transfer tool and causing a short circuit.

4. A MEMS accelerometer scale factor batch testing device according to any one of claims 1 to 3, characterized in that: The number of the test fixtures is an even number, at least 4.

5. A MEMS accelerometer scale factor batch testing device according to claim 4, characterized in that: The accelerometer fixing device includes a base, a probe structure and an upper cover. The base is fixed on a circuit board. The base has a positioning groove. The accelerometer is placed in the positioning groove in a fixed installation direction. The upper cover presses the accelerometer downward to push out the probe structure. The top of the probe structure contacts the accelerometer tube leg, and the bottom of the probe structure contacts the circuit board pad, thereby realizing the electrical connection between the circuit board and the accelerometer.

6. A MEMS accelerometer scale factor batch testing device according to any one of claims 1 to 5, characterized in that: The accelerometer data measured during centrifugation were corrected by the following method: After the accelerometer is installed, input 1g acceleration to it, measure the output value at this time, and divide it by the actual scale factor of the accelerometer to obtain the proportional coefficient K; The data measured during the centrifugation process are multiplied by this coefficient to calculate a new output value, and the scale factor symmetry value after excluding the installation error is calculated through this output value.

7. The device for batch testing of MEMS accelerometer scale factors according to claim 1, characterized in that: The fixed base plate is made of aluminum, and a protective layer is formed on its surface by passivation to insulate it from other components.

8. The device for batch testing of MEMS accelerometer scale factors according to claim 7, characterized in that: The test circuit transfer tooling is made of aluminum, and a protective layer is formed on its surface by passivation, thereby isolating the tooling from the batch test circuit board.

9. A method for batch testing of MEMS accelerometer scale factor, characterized in that: The method comprises: Installing the device according to any one of claims 1 to 8; After the device is installed, collect the accelerometer output data, including: First, the accelerometer is installed in the positive acceleration input test circuit, and the corresponding acceleration is input according to the test requirements. At the same time, the accelerometer output value is collected through the acquisition system. Then, the accelerometer is installed in the negative acceleration input test circuit to complete the negative acceleration value data collection; Process the acquired data and calculate the accelerometer scale factor symmetry: Install the accelerometer on the test circuit board, input 1g acceleration to it, measure the output value at this time, and divide it with the actual scale factor to obtain the proportional coefficient K; The data measured during the centrifugation process are multiplied by this coefficient to calculate a new output value, and the scale factor symmetry value after excluding the installation error is calculated through this output value.

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