An automated inertial measurement unit calibration and testing system and method

Abstract

The present invention belongs to the technical field of calibration and testing of inertial measurement units, and specifically discloses an automated calibration and testing system and method for inertial measurement units. The method includes the following steps: fixing the inertial measurement unit to be tested on a three-axis rate turntable inside a high and low temperature test chamber through a tooling; controlling the three-axis rate turntable and the temperature chamber to perform multiple groups of rate and position point tests at different temperature points, and collecting the sensor data of the inertial measurement unit; calculating the mean value of the sensor data of the inertial measurement unit, and calculating the parameters of the inertial measurement unit according to the mean value by using an integrated parameter calculation and online injection software; uploading the parameters of the inertial measurement unit through the integrated parameter calculation and online injection software to complete the automated calibration and testing of the inertial measurement unit. The present invention solves the problems in the prior art of excessive dependence on personnel in the testing and calibration of inertial measurement units, increased labor intensity caused by traditional offline upgrades, and relatively high risks of product damage.

Description

Technical Field

[0001] The present invention belongs to the technical field of calibration and testing of inertial measurement units, and particularly relates to an automated inertial measurement unit calibration and testing system and method. Background Art

[0002] With the improvement of the accuracy and the reduction of the cost of inertial devices such as fiber optic gyroscopes and MEMS gyroscopes, inertial measurement units are more and more widely used in the fields of weapon manufacturing, industrial manufacturing and consumer electronics, and their production scale is getting larger and larger. With the reduction of device cost and the expansion of application scale, the calibration and testing of inertial measurement units have gradually become the bottleneck restricting the reduction of their cost and application. Conventional calibration and testing of inertial measurement units separate testing and data processing, that is, first collect and record data, and then export the data for manual processing, or import it into Matlab or Excel for calculation, with low efficiency. At the same time, the calibration parameters of conventional inertial measurement units are all parameter values of calculated linear or non-linear functions, and they do not have intuitive physical meanings themselves, which brings difficulties to parameter inspection and verification.

[0003] When the production quantity of inertial measurement units increases, a large amount of data will lead to chaos in the production process, resulting in product compensation errors and ultimately reducing efficiency and increasing production costs. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems of excessive dependence on personnel in the testing and calibration of inertial measurement units in the prior art, increased labor intensity brought by traditional offline upgrades, and relatively high risk of product damage, and proposes an automated inertial measurement unit calibration and testing system and method.

[0005] The technical solution of the present invention is as follows: In the first aspect, an automated inertial measurement unit calibration and testing system includes an industrial control computer, a high and low temperature test chamber, a serial port acquisition card, and a three-axis rate turntable;

[0006] The three-axis rate turntable is located inside the high and low temperature test chamber; the serial port acquisition card is communicatively connected to the three-axis rate turntable, the high and low temperature test chamber, and the industrial control computer respectively.

[0007] In the second aspect, an automated inertial measurement unit calibration and testing method includes the following steps:

[0008] S1. Fix the inertial measurement unit to be tested on the three-axis rate turntable inside the high and low temperature test chamber through a tooling;

[0009] S2. Send operation control instructions to the three-axis rate turntable and the high and low temperature test chamber through the integrated device control and data acquisition software on the industrial control computer to perform multiple groups of rate and position point tests, and collect sensor data of the inertial measurement unit at different temperature points;

[0010] S3. Calculate the mean of the sensor data of each inertial measurement unit, and calculate the parameters of the inertial measurement unit using the integrated parameter calculation and online injection software on the industrial computer based on the mean;

[0011] S4. The parameters of the inertial measurement unit are injected through the integrated parameter calculation and online injection software on the industrial computer to complete the automated inertial measurement unit calibration test.

[0012] Preferably, the temperature points in step S2 include -55°C, -40°C, -25°C, -10°C, +5°C, +25°C, +40°C, +55°C and +70°C.

[0013] Preferably, the parameters of the inertial measurement unit in step S3 include temperature parameters, three-axis gyroscope zero bias, three-axis gyroscope positive scale factor, three-axis gyroscope negative scale factor, three-axis gyroscope axis misalignment parameter, three-axis added zero bias, three-axis added positive scale factor, three-axis added negative scale factor and three-axis added axis misalignment parameter.

[0014] Preferably, the calculation formula of the temperature parameter is:

[0015]

[0016] in, Indicates the The average temperature at each temperature point, Indicates the Temperature point The average temperature at each location.

[0017] Preferably, the calculation formula of the three-axis gyroscope zero bias is:

[0018]

[0019] in, Indicates the Temperature point The gyroscopic zero bias of the axis, Indicates the Temperature point The gyroscopic zero bias of the axis, Indicates the Temperature point The gyroscopic zero bias of the axis, Indicates the Temperature point Locations The gyro mean of the axis, Indicates the Temperature point Locations The gyro mean value of the axis denotes the th gyro mean value of the axis at the th position under the

[0020] The calculation formula for the positive scale factor of the three-axis gyro is:

[0021]

[0022] where denotes the positive scale factor of the gyro of the axis under the th temperature point, denotes the positive scale factor of the gyro of the axis under the th temperature point, denotes the positive scale factor of the gyro of the axis under the th temperature point;

[0023] The calculation formula for the negative scale factor of the three-axis gyro is:

[0024]

[0025] where denotes the negative scale factor of the gyro of the axis under the th temperature point, denotes the negative scale factor of the gyro of the axis under the th temperature point, denotes the negative scale factor of the gyro of the axis under the th temperature point;

[0026] The calculation formula for the axis misalignment parameter of the three-axis gyro is:

[0027]

[0028] where denotes the misalignment angle of the gyro of the axis coupled to the axis under the th temperature point, denotes the misalignment angle of the gyro of the axis coupled to the axis under the th temperature point, denotes the misalignment angle of the gyro of the axis coupled to the axis under the th temperature point, Indicates the Temperature point axis gyro coupled to The misalignment angle of the axis, Indicates the Temperature point axis gyro coupled to The misalignment angle of the axis, Indicates the Temperature point axis gyro coupled to The misalignment angle of the axis.

[0029] Preferably, the calculation formula of the three-axis added zero bias is:

[0030]

[0031] in, Indicates the Temperature point Additive zero offset of the axis, Indicates the Temperature point Additive zero offset of the axis, Indicates the Temperature point Additive zero offset of the axis, Indicates the Temperature point Locations The summed mean of the axis, Indicates the Temperature point Locations The summed mean of the axis, Indicates the Temperature point Locations The summed mean of the axes;

[0032] The calculation formula of the three-axis plus positive scale factor is:

[0033]

[0034] in, Indicates the Temperature point The added positive scale factor of the axis, Indicates the Temperature point The added positive scale factor of the axis, Indicates the Temperature point The added positive scale factor of the axis, is the acceleration due to gravity;

[0035] The calculation formula for the negative scale factor of the three-axis accelerometer is:

[0036]

[0037] where, represents the negative scale factor of the accelerometer on the axis at the th temperature point, represents the negative scale factor of the accelerometer on the axis at the th temperature point, represents the negative scale factor of the accelerometer on the axis at the th temperature point;

[0038] The calculation formula for the misalignment parameter of the three-axis accelerometer axis is:

[0039]

[0040] where, represents the misalignment angle of the gyro-accelerometer coupling on the axis coupled to the axis at the th temperature point, represents the misalignment angle of the gyro-accelerometer coupling on the axis coupled to the axis at the th temperature point, represents the misalignment angle of the gyro-accelerometer coupling on the axis coupled to the axis at the th temperature point, represents the misalignment angle of the gyro-accelerometer coupling on the axis coupled to the axis at the th temperature point, represents the misalignment angle of the gyro-accelerometer coupling on the axis coupled to the axis at the th temperature point, represents the misalignment angle of the gyro-accelerometer coupling on the axis coupled to the axis at the th temperature point.

[0041] Preferably, the step S4 is specifically: Open the integrated parameter calculation and online injection software, set the path to the storage location of the current compensated inertial measurement unit data, click parameter writing to complete the parameter uploading. The injection time and product number information will be recorded during the parameter uploading process, and the automated inertial measurement unit calibration test is completed.

[0042] Preferably, when uploading the parameters of the inertial measurement unit in step S4, a combined communication mode of time-domain gating and command handshake is adopted.

[0043] The beneficial effects of the present invention are as follows:

[0044] 1. The method proposed by the present invention realizes full automation in the whole process from inertial measurement unit testing, parameter calculation to parameter uploading, reduces human intervention, reduces the risk of human error and the work intensity of personnel, and improves the efficiency of testing the inertial measurement unit;

[0045] 2. The present invention provides a new, feasible and clear calibration test method for high-precision inertial measurement units under full temperature conditions, namely 30 static and dynamic test methods. Using the point data of 30 positions in three-dimensional inertial space, the full-temperature zero-offset values, scale factors and their respective axis misalignment parameters of three-axis fiber optic gyroscopes and three-axis accelerometers are calculated;

[0046] 3. The present invention provides a new parameter uploading method and data storage method for temperature compensation, zero-offset correction and axis misalignment compensation of inertial measurement units with all parameters, which can intuitively display sensor parameters and greatly facilitate the compensation and data verification of inertial measurement units under full temperature conditions. Description of the Drawings

[0047] Figure 1 The figure shows the structure diagram of an automated inertial measurement unit calibration test system provided in Embodiment 1 of the present invention.

[0048] Figure 2 The figure shows the flowchart of an automated inertial measurement unit calibration test method provided in Embodiment 2 of the present invention.

[0049] Figure 3 The figure shows the flowchart of uploading the parameters of the inertial measurement unit through the integrated parameter calculation and online injection software on the industrial control computer provided in Embodiment 2 of the present invention.

[0050] Reference Signs: 1. Industrial control computer; 2. High and low temperature test chamber; 3. Serial port acquisition card; 4. Three-axis rate turntable; 5. USB device. Detailed Embodiments

[0051] Now, the exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood that the embodiments shown and described in the drawings are merely exemplary, intended to illustrate the principles and spirit of the present invention, and not to limit the scope of the present invention.

[0052] Embodiment 1:

[0053] An automated inertial measurement unit calibration and testing system, as Figure 1 shown, includes an industrial control computer 1, a high and low temperature test chamber 2, a serial port acquisition card 3, and a three-axis rate turntable 4;

[0054] The three-axis rate turntable 4 is located inside the high and low temperature test chamber 2; the serial port acquisition card 3 is respectively communicatively connected to the three-axis rate turntable 4, the high and low temperature test chamber 2, and the industrial control computer 1.

[0055] In this embodiment, the inertial measurement unit to be tested is fixed on the three-axis rate turntable 4. The industrial control computer 1 sends operation control instructions to the serial port acquisition card 3, and the serial port acquisition card 3 transmits the operation control instructions to the high and low temperature test chamber 2 and the three-axis rate turntable 4 respectively through the RS232 bus; the high and low temperature test chamber 2 receives the operation control instructions and provides different temperatures for the calibration and testing of the inertial measurement unit; after receiving the operation control instructions, the three-axis rate turntable 4 performs 30-position tests, obtains the sensor data of the inertial measurement unit at different temperatures and different positions, transmits the sensor data of the inertial measurement unit at different temperatures and different positions to the serial port acquisition card 3 through the RS422 serial bus, and the serial port acquisition card 3 transmits the sensor data to the industrial control computer 1 through the USB device 5. Data processing is performed through the integrated device control and data acquisition software on the industrial control computer 1 to calculate the parameters of the inertial measurement unit, and then parameter uploading is performed using the integrated parameter calculation and online injection software on the industrial control computer 1.

[0056] Embodiment 2:

[0057] Based on Embodiment 1, this embodiment provides an automated inertial measurement unit calibration and testing method, as Figure 2 shown, including the following steps:

[0058] S1. Fix the inertial measurement unit to be tested on the three-axis rate turntable 4 inside the high and low temperature test chamber 2 through a tooling.

[0059] S2. Send operation control instructions to the three-axis rate turntable 4 and the high and low temperature test chamber 2 through the integrated device control and data acquisition software on the industrial control computer 1, perform multiple groups of rate and position point tests, and collect the sensor data of the inertial measurement unit at different temperature points.

[0060] In this embodiment, a total of 30 tests including rate tests and position tests are performed, abbreviated as 30-position tests. The temperature points include -55°C, -40°C, -25°C, -10°C, +5°C, +25°C, +40°C, +55°C, and +70°C; the actions and corresponding times of the three-axis rate turntable 4 at each temperature point are shown in Table 1;

[0061] Table 1 Actions and times of the three-axis rate turntable

[0062]

[0063]

[0064] S3. Calculate the mean value of the sensor data of each inertial measurement unit at the 30 positions. According to the mean value, use the integrated parameter calculation and online injection software on the industrial control computer 1 to calculate the parameters of the inertial measurement unit; after the calculation is completed, store the parameters of the inertial measurement unit in the Cpsfile.txt file in the folder named after the serial number of the inertial measurement unit through the integrated parameter calculation and online injection software; the parameters of the inertial measurement unit include temperature parameter, zero bias of three-axis gyroscopes, positive scale factor of three-axis gyroscopes, negative scale factor of three-axis gyroscopes, axis misalignment parameter of three-axis gyroscopes, zero bias of three-axis accelerometers, positive scale factor of three-axis accelerometers, negative scale factor of three-axis accelerometers, and axis misalignment parameter of three-axis accelerometers; the mean value of the sensor data of each inertial measurement unit is shown in Table 2;

[0065] Table 2 List of Mean Values of Sensor Data

[0066]

[0067] In this embodiment, the calculation formula of the temperature parameter is:

[0068]

[0069] Among them, represents the mean temperature at the th temperature point, represents the mean temperature at the th temperature point and the rd position.

[0070] In this embodiment, the calculation formula of the zero bias of three-axis gyroscopes is:

[0071]

[0072] Among them, represents the gyro zero bias of the th temperature point and the axis, represents the gyro zero bias of the th temperature point and the axis, represents the gyro zero bias of the th temperature point and the axis, represents the gyro mean value of the th temperature point and the th position and the axis, represents the gyro mean value of the -axis at the th position under the th temperature point; represents the gyro mean value of the -axis at the th position under the th temperature point;

[0073] The calculation formula for the positive scale factor of the three-axis gyro is:

[0074]

[0075] where represents the positive scale factor of the -axis gyro at the th temperature point, represents the positive scale factor of the -axis gyro at the th temperature point, represents the positive scale factor of the -axis gyro at the th temperature point;

[0076] The calculation formula for the negative scale factor of the three-axis gyro is:

[0077]

[0078] where in represents the negative scale factor of the -axis gyro at the th temperature point, represents the negative scale factor of the -axis gyro at the th temperature point, represents the negative scale factor of the -axis gyro at the th temperature point;

[0079] The calculation formula for the axis misalignment parameter of the three-axis gyro is:

[0080]

[0081] where represents the misalignment angle of the -axis gyro coupled to the -axis at the th temperature point, represents the misalignment angle of the -axis gyro coupled to the -axis at the th temperature point, represents the misalignment angle of the at each temperature point the misalignment angle of the axis gyro coupled to the denotes the misalignment angle of the axis gyro coupled to the axis at the denotes the misalignment angle of the axis gyro coupled to the axis at the denotes the misalignment angle of the axis gyro coupled to the axis.

[0082] In this embodiment, the calculation formula for the zero bias of the three-axis accelerometer is:

[0083]

[0084] where denotes the zero bias of the axis accelerometer at the th temperature point, denotes the zero bias of the axis accelerometer at the th temperature point, denotes the zero bias of the axis accelerometer at the th temperature point, denotes the average value of the axis accelerometer at the th position at the th temperature point, denotes the average value of the axis accelerometer at the th position at the th temperature point, denotes the average value of the axis accelerometer at the th position at the th temperature point;

[0085] The calculation formula for the positive scale factor of the three-axis accelerometer is:

[0086]

[0087] where denotes the positive scale factor of the axis accelerometer at the th temperature point, denotes the positive scale factor of the axis accelerometer at the th temperature point, denotes the at each temperature point the positive scale factor of the accelerometer along the axis, where

[0088] The formula for the negative scale factor of the three-axis accelerometer is:

[0089]

[0090] where represents the negative scale factor of the accelerometer along the axis at the th temperature point, represents the negative scale factor of the accelerometer along the axis at the th temperature point, represents the negative scale factor of the accelerometer along the axis at the th temperature point;

[0091] The formula for the misalignment parameter of the three-axis accelerometer is:

[0092]

[0093] where represents the misalignment angle of the gyro-accelerometer coupling from the axis to the axis at the th temperature point, represents the misalignment angle of the gyro-accelerometer coupling from the axis to the axis at the th temperature point, represents the misalignment angle of the gyro-accelerometer coupling from the axis to the axis at the th temperature point, represents the misalignment angle of the gyro-accelerometer coupling from the axis to the axis at the th temperature point, represents the misalignment angle of the gyro-accelerometer coupling from the axis to the axis at the th temperature point, represents the misalignment angle of the gyro-accelerometer coupling from the axis to the axis at the th temperature point,

[0094] S4. Upload the parameters of the inertial measurement unit through the integrated parameter calculation and online injection software on the industrial control computer 1. Specifically: Open the integrated parameter calculation and online injection software, set the path to the storage location of the inertial measurement unit data currently compensated, and click "Write Parameter" to complete the parameter upload. The injection time and product number information will be recorded during the parameter upload process to complete the automated calibration test of the inertial measurement unit. The integrated parameter calculation and online injection software has the functions of parameter readback and report generation, which can read back the compensation data of the inertial measurement unit and generate a report to record it as the key parameters of the product. The parameter recording form is shown in Table 3.

[0095] Table 3 Inertial Measurement Unit Parameter Recording Form

[0096]

[0097] In this embodiment, as Figure 3 shown, when uploading the parameters of the inertial measurement unit in step S4, a combined communication mode of time-domain gating and command handshake is adopted. The inertial measurement unit responds to the external parameter upgrade command within 1 s after power-on, and does not respond to the external parameter upgrade command after exceeding 1 s. If the handshake command is received within 1 s, it will enter the waiting mode, select to click on the selected compensation parameter TXT file, and click "Parameter Upload" to complete the upgrade. At the same time, this upgrade method has the function of parameter readback to facilitate the confirmation of the product status.

[0098] Those of ordinary skill in the art will realize that the embodiments described herein are to assist the reader in understanding the principles of the present invention and should be understood that the scope of protection of the present invention is not limited to such specific statements and embodiments. Those of ordinary skill in the art can make various other specific deformations and combinations that do not depart from the essence of the present invention based on the technical revelations disclosed in the present invention, and these deformations and combinations are still within the scope of protection of the present invention.

Claims

1. An automated calibration test method for an inertial measurement unit, characterized in that, Including the following steps: S1. Fix the inertial measurement unit to be tested on the three-axis rate turntable (4) inside the high and low temperature test chamber (2) through a tooling fixture; S2. Send operation control instructions to the three-axis rate turntable (4) and the high and low temperature test chamber (2) through the integrated equipment control and data acquisition software on the industrial control computer (1), conduct a total of 30 tests including rate tests and position tests, and collect the sensor data of the inertial measurement unit at different temperature points; S3. Calculate the mean value of the sensor data of each inertial measurement unit, and calculate the parameters of the inertial measurement unit according to the mean value using the integrated parameter calculation and online injection software on the industrial control computer (1); S4. Perform upper injection of the parameters of the inertial measurement unit through the integrated parameter calculation and online injection software on the industrial control computer (1) to complete the automated calibration test of the inertial measurement unit. Specifically: Open the integrated parameter calculation and online injection software, set the path to the data storage location of the currently compensated inertial measurement unit, click parameter writing to complete parameter upper injection. The injection time and product number information will be recorded during the parameter upper injection process to complete the automated calibration test of the inertial measurement unit; When performing upper injection of the parameters of the inertial measurement unit, a combined communication mode of time-domain gating and command handshake is adopted. The inertial measurement unit responds to the external parameter upgrade command within 1 s after power-on, and does not respond to the external parameter upgrade command after exceeding 1 s; If the handshake command is received within 1 s, it will enter the waiting mode. Click to select the compensated parameter TXT file, and click parameter upper injection to complete the upgrade; at the same time, the integrated parameter calculation and online injection software has a parameter read-back function, reads back the compensated data of the inertial measurement unit and generates a report to record it as the key parameters of the product; The temperature points include -55°C, -40°C, -25°C, -10°C, +5°C, +25°C, +40°C, +55°C, and +70°C.

2. The automated inertial measurement unit calibration test method according to claim 1, wherein The parameters of the inertial measurement unit in step S3 include temperature parameters, three-axis gyro zero biases, three-axis gyro positive scale factors, three-axis gyro negative scale factors, three-axis gyro axis misalignment parameters, three-axis accelerometer zero biases, three-axis accelerometer positive scale factors, three-axis accelerometer negative scale factors, and three-axis accelerometer axis misalignment parameters.

3. The automated inertial measurement unit calibration test method according to claim 2, wherein The calculation formula for the temperature parameter is: Among them, represents the average temperature at the th temperature point, represents the average temperature at the th temperature point at the th position.

4. The automated inertial measurement unit calibration and testing method according to claim 2, wherein, The calculation formula for the three-axis gyro zero bias is: Among them, represents the gyro zero bias of the axis at the th temperature point, represents the gyro zero bias of the axis at the th temperature point, represents the gyro zero bias of the axis at the th temperature point, represents the gyro mean value of the axis at the th position at the th temperature point, represents the gyro mean value of the axis at the th position at the th temperature point, represents the gyro mean value of the axis at the th position at the th temperature point; The calculation formula for the three-axis gyro positive scale factor is: Among them, represents the gyro positive scale factor of the axis at the th temperature point, represents the gyro positive scale factor of the axis at the th temperature point, represents the gyro positive scale factor of the axis at the th temperature point; The calculation formula for the three-axis gyro negative scale factor is: Among them, represents the gyro negative scale factor of the axis at the th temperature point, represents the gyro negative scale factor of the axis at the th temperature point, represents the gyro negative scale factor of the The calculation formula for the three-axis gyro axis misalignment parameter is: Among them, represents the misalignment angle of the axis gyro coupled to the axis at the th temperature point, represents the misalignment angle of the axis gyro coupled to the axis at the th temperature point, represents the misalignment angle of the axis gyro coupled to the axis at the th temperature point, represents the misalignment angle of the axis gyro coupled to the axis at the th temperature point, represents the misalignment angle of the axis gyro coupled to the axis at the th temperature point.

5. The automated inertial measurement unit calibration and testing method according to claim 2, characterized in that The calculation formula for the three-axis accelerometer zero bias is: Among them, represents the zero bias of the accelerometer on the axis at the th temperature point, represents the zero bias of the accelerometer on the axis at the th temperature point, represents the zero bias of the accelerometer on the axis at the th position at the th temperature point, represents the th position at the th temperature point, represents the average value of the accelerometer on the axis at the th position at the th temperature point; The calculation formula for the three-axis accelerometer positive scale factor is: Among them, represents the positive scale factor of the accelerometer along the axis at the th temperature point, represents the positive scale factor of the accelerometer along the axis at the th temperature point, represents the positive scale factor of the accelerometer along the axis at the th temperature point, where is the acceleration due to gravity; The calculation formula for the three-axis accelerometer negative scale factor is: Among them, represents the negative scale factor of the accelerometer on the axis at the th temperature point, represents the negative scale factor of the accelerometer on the axis at the th temperature point, represents the negative scale factor of the accelerometer on the axis at the th temperature point; The calculation formula for the three-axis accelerometer axis misalignment parameter is: Among them, represents the misalignment angle at the -axis gyro accelerometer coupled to the -axis at the th temperature point, represents the misalignment angle at the -axis gyro accelerometer coupled to the -axis at the th temperature point, represents the misalignment angle at the -axis gyro accelerometer coupled to the -axis at the th temperature point, represents the misalignment angle at the -axis gyro accelerometer coupled to the -axis at the th temperature point, represents the misalignment angle at the -axis gyro accelerometer coupled to the -axis at the th temperature point.

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