Inertial measurement unit calibration method, apparatus, and device

Abstract

The application provides an inertial measurement unit calibration method, device and equipment, the method comprising: determining an acceleration standard value; when the inertial measurement unit is in a first installation state, obtaining an eccentricity of the inertial measurement unit, and determining a first rotation speed according to the acceleration standard value and the eccentricity, wherein when the inertial measurement unit is in the first installation state, the inertial measurement unit is eccentrically installed on a workbench of a rotation device, a to-be-measured coordinate axis of the inertial measurement unit is parallel to a radial direction of a main shaft connected with the workbench, and the to-be-measured coordinate axis is perpendicular to a gravity direction; the main shaft is controlled to rotate at the first rotation speed, and an acceleration measurement value of the to-be-measured coordinate axis is obtained; and a value error of the acceleration measurement value is calculated according to the acceleration standard value and the corresponding acceleration measurement value. Through the application, a series of acceleration standard values can be set according to the range of the inertial measurement unit, the acceleration measurement values under each acceleration standard value are obtained and calibrated, and the practicability of the calibration result is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of inertial measurement unit, and particularly relates to an inertial measurement unit calibration method, device and equipment. BACKGROUND

[0002] An IMU (Inertial Measurement Unit) is an advanced inertial measurement sensor, which has the advantages of high measurement accuracy, multiple functions, portability and the like. The IMU overcomes the disadvantages of mechanical gyroscopes, such as being heavy and having poor precision, and is applied to the fields of spaceflight, automobiles and consumer electronics. In order to ensure the accuracy and reliability of measurement data, the inertial measurement unit needs to be regularly calibrated scientifically and normatively. In the existing inertial measurement unit calibration method, the gravity acceleration excitation overturning method is usually used to calibrate the acceleration of each axis of the inertial measurement unit. The inertial measurement unit is arranged on a leveled platform in two attitudes of a to-be-measured coordinate axis being upward and downward, so as to calibrate two calibration points of g and -g. The gravity acceleration excitation overturning method cannot set appropriate calibration points for the range of the inertial measurement unit, resulting in low practicability of the calibration result. SUMMARY

[0003] The main purpose of the present application is to provide an inertial measurement unit calibration method, device and equipment, which aims to solve the technical problem of low practicability of the calibration result of the gravity acceleration excitation overturning method used in the inertial measurement unit calibration method in the prior art.

[0004] In a first aspect, the present application provides an inertial measurement unit calibration method, which comprises:

[0005] determining an acceleration standard value;

[0006] when the inertial measurement unit is in a first installation state, obtaining an eccentricity of the inertial measurement unit, and determining a first rotation speed according to the acceleration standard value and the eccentricity, wherein when the inertial measurement unit is in the first installation state, the inertial measurement unit is eccentrically installed on a workbench of a rotation device, a to-be-measured coordinate axis of the inertial measurement unit is parallel to a radial direction of a main shaft connected with the workbench, and the to-be-measured coordinate axis is perpendicular to a gravity direction;

[0007] controlling the main shaft to rotate at the first rotation speed, and obtaining an acceleration measurement value of the to-be-measured coordinate axis;

[0008] calculating a indication error of the acceleration measurement value according to the acceleration standard value and the corresponding acceleration measurement value.

[0009] Optionally, the step of determining the first rotation speed according to the acceleration standard value and the eccentricity comprises:

[0010] The acceleration standard value and the eccentricity are substituted into a first formula to calculate a first rotation speed, the first formula being:

[0011]

[0012] wherein n is the first rotation speed, a is the acceleration standard value, and r is the eccentricity.

[0013] Optionally, the step of calculating the indication error of the acceleration measurement value according to the acceleration standard value and the corresponding acceleration measurement value further comprises:

[0014] When the inertial measurement unit is in the first installation state, the step of controlling the main shaft to rotate at the first rotation speed and obtaining the acceleration measurement value of the to-be-measured coordinate axis is repeatedly performed;

[0015] According to a plurality of acceleration measurement values corresponding to the same first rotation speed, a repeatability error of the acceleration measurement value is calculated.

[0016] Optionally, the step of determining the acceleration standard value further comprises:

[0017] If the acceleration standard value is less than or equal to the gravitational acceleration, when the inertial measurement unit is in a second installation state, a flip angle is determined according to the acceleration standard value and the gravitational acceleration, wherein when the inertial measurement unit is in the second installation state, the inertial measurement unit is centrally installed on the workbench, and a to-be-measured coordinate axis of the inertial measurement unit is collinear with an axis of the main shaft.

[0018] A pitch shaft connected to the main shaft is controlled to rotate to a position corresponding to the flip angle to obtain the acceleration measurement value of the to-be-measured coordinate axis.

[0019] Optionally, the step of determining the flip angle according to the acceleration standard value and the gravitational acceleration comprises:

[0020] The acceleration standard value is substituted into a second formula to calculate the flip angle, the second formula being:

[0021]

[0022] wherein θ is the flip angle, the flip angle being an included angle between the to-be-measured coordinate axis and a gravitational direction, a is the acceleration standard value, and g is the gravitational acceleration.

[0023] Optionally, the step of calculating the indication error of the acceleration measurement value according to the acceleration standard value and the corresponding acceleration measurement value further comprises:

[0024] repeating the step of controlling the main shaft to rotate to a position corresponding to the flip angle to obtain the acceleration measurement value of the to-be-measured coordinate axis when the inertial measurement unit is in the second installation state;

[0025] calculating the repeatability error of the acceleration measurement value according to a plurality of acceleration measurement values corresponding to the same flip angle.

[0026] Optionally, the inertial measurement unit calibration method further comprises:

[0027] determining an angular velocity standard value;

[0028] determining a second rotating speed according to the angular velocity standard value when the inertial measurement unit is in a third installation state, wherein the inertial measurement unit is centrally installed on the workbench when the inertial measurement unit is in the third installation state, the to-be-measured coordinate axis of the inertial measurement unit is collinear with the axis of the main shaft, and the to-be-measured coordinate axis is parallel to the direction of gravity;

[0029] controlling the main shaft to rotate at the second rotating speed to obtain an angular velocity measurement value of the to-be-measured coordinate axis;

[0030] calculating the indication error of the angular velocity measurement value according to the angular velocity standard value and the corresponding angular velocity measurement value.

[0031] Optionally, the inertial measurement unit calibration method further comprises:

[0032] repeating the step of controlling the main shaft to rotate at the second rotating speed to obtain the angular velocity measurement value of the to-be-measured coordinate axis when the inertial measurement unit is in the third installation state;

[0033] calculating the repeatability error of the angular velocity measurement value according to a plurality of angular velocity measurement values corresponding to the same second rotating speed.

[0034] In a second aspect, the present application further provides an inertial measurement unit calibration device, which comprises:

[0035] a standard module configured to determine an acceleration standard value;

[0036] The conversion module is used to obtain the eccentricity of the inertial measurement unit when the inertial measurement unit is in the first installation state, and determine the first rotational speed according to the acceleration standard value and the eccentricity. When the inertial measurement unit is in the first installation state, the inertial measurement unit is eccentrically installed on the worktable of the indexing device, the coordinate axis to be measured of the inertial measurement unit is parallel to the radial direction of the main shaft connected to the worktable, and the coordinate axis to be measured is perpendicular to the direction of gravity.

[0037] An execution module is used to control the spindle to rotate at the first rotational speed to obtain the acceleration measurement value of the coordinate axis to be measured;

[0038] The error module is used to calculate the indication error of the acceleration measurement value based on the acceleration standard value and the corresponding acceleration measurement value.

[0039] Thirdly, the present invention also provides an inertial measurement unit (IMU) calibration device, the IMU calibration device including a processor, a memory, and an IMU calibration program stored in the memory and executable by the processor, wherein when the IMU calibration program is executed by the processor, the steps of the above-described IMU calibration method are implemented.

[0040] In this invention, an inertial measurement unit (IMU) is eccentrically mounted on the worktable of a rotational device. When the IMU's eccentricity is constant, the spindle is controlled to rotate at a first rotational speed to generate centripetal acceleration in the IMU. This centripetal acceleration is the standard acceleration value. Different standard acceleration values ​​can be obtained by changing the eccentricity or the first rotational speed. This invention allows for setting a series of standard acceleration values ​​for the IMU's range, obtaining acceleration measurements under each standard value, and performing calibration, thus improving the practicality of the calibration results. Attached Figure Description

[0041] Figure 1 This is a flowchart illustrating an inertial measurement unit calibration method according to an embodiment of the present invention;

[0042] Figure 2 This is a schematic diagram of the inertial measurement unit.

[0043] Figure 3 This is a schematic diagram of an inertial measurement unit in a first installation state according to an embodiment of the present invention;

[0044] Figure 4 This is a schematic diagram showing the inertial measurement unit in a second or third installation state according to one embodiment of the present invention;

[0045] Figure 5 This is a schematic diagram of the hardware structure of an inertial measurement unit calibration device according to an embodiment of the present invention.

[0046] Reference Signs List:

[0047] 10, inertial measurement unit; 20, indexing device; 21, worktable; 22, main shaft; 23, pitch shaft. DETAILED DESCRIPTION

[0048] It should be understood that the specific embodiments described herein are merely exemplary and not intended to limit the application.

[0049] In a first aspect, embodiments of the present application provide an inertial measurement unit calibration method.

[0050] Figure 1 A flowchart of the inertial measurement unit calibration method in an embodiment of the present application is shown;

[0051] Referring to Figure 1 In an embodiment, the inertial measurement unit calibration method comprises the following steps:

[0052] S11, determining an acceleration standard value;

[0053] In this embodiment, the acceleration standard value corresponds to a calibration point set by an operator, and the value error of the acceleration measurement value is obtained by comparing the acceleration measurement value of the inertial measurement unit corresponding to the acceleration standard value, thereby completing the calibration of the acceleration. The acceleration standard value can be set according to the range of the inertial measurement unit to improve the practicality of the calibration result.

[0054] S12, when the inertial measurement unit is in a first installation state, obtaining an eccentricity of the inertial measurement unit, and determining a first rotation speed according to the acceleration standard value and the eccentricity, wherein when the inertial measurement unit is in the first installation state, the inertial measurement unit is eccentrically installed on a worktable of an indexing device, a to-be-measured coordinate axis of the inertial measurement unit is parallel to a radial direction of a main shaft connected to the worktable, and the to-be-measured coordinate axis is perpendicular to a gravity direction;

[0055] Figure 2 A structural diagram of the inertial measurement unit is shown; Figure 3 A diagram showing the inertial measurement unit in the first installation state in an embodiment of the present application is shown.

[0056] Referring to Figure 2 The inertial measurement unit comprises three angular velocity sensors (three-axis angular velocity sensors) and three accelerometers (three-axis accelerometers) for measuring yaw angular velocity, pitch angular velocity, roll angular velocity, X-direction acceleration, Y-direction acceleration, and Z-direction acceleration. In this embodiment, the to-be-measured coordinate axis of the inertial measurement unit can be selected as the X-axis, Y-axis, or Z-axis in the inertial measurement unit. Figure 2

[0057] Referring to Figure 3 ​In the embodiment, the rotating device 20 comprises a workbench 21 and a spindle 22, the workbench 21 is connected to the top end of the spindle 22 to rotate synchronously with the spindle 22. When the inertial measurement unit 10 is in the first installation state, the inertial measurement unit 10 is eccentrically installed on the workbench 21, that is, the center of the inertial measurement unit 10 has an eccentricity r with the axis of the spindle 22, the to-be-measured coordinate axis of the inertial measurement unit 10 is parallel to the radial direction of the spindle 22, and the to-be-measured coordinate axis is perpendicular to the direction of gravity. In this way, when the spindle 22 rotates at a constant speed, the inertial measurement unit 10 moves in a uniform circular motion and has a certain centripetal acceleration, and the direction of the centripetal acceleration is parallel to the to-be-measured coordinate axis and points to the axis of the spindle 22. It can be understood that different centripetal accelerations can be obtained by changing the eccentricity r or the first rotating speed, and in the case of a certain eccentricity r, the first rotating speed can be determined according to the acceleration standard value and the eccentricity r, so that the corresponding centripetal acceleration is equal to the acceleration standard value.

[0058] It should be noted that the positive direction of the to-be-measured coordinate axis is opposite to the direction of the centripetal acceleration in the figure, and is used to calibrate the part with a negative range. When it is necessary to calibrate the part with a positive range, the inertial measurement unit 10 needs to be reinstalled so that the positive direction of the to-be-measured coordinate axis is the same as the direction of the centripetal acceleration.

[0059] Specifically, the step of determining the first rotating speed according to the acceleration standard value and the eccentricity comprises:

[0060] The first rotating speed is calculated by substituting the acceleration standard value and the eccentricity into the first formula, and the first formula is:

[0061]

[0062] Wherein, n is the first rotating speed, a is the acceleration standard value, and r is the eccentricity.

[0063] In the embodiment, the first formula is converted from the centripetal acceleration formula a=ω 2 r, the unit of n is r / min, the unit of a is m / s 2 , and the unit of r is m.

[0064] S13, control the spindle to rotate at the first rotating speed to obtain an acceleration measurement value of the to-be-measured coordinate axis.

[0065] In the embodiment, when the spindle rotates at a constant speed at the first rotating speed, the centripetal acceleration of the inertial measurement unit is equal to the acceleration standard value, and the inertial measurement unit measures the corresponding acceleration measurement value of the to-be-measured coordinate axis.

[0066] S14, calculate the indication error of the acceleration measurement value according to the acceleration standard value and the corresponding acceleration measurement value.

[0067] In the embodiment, the acceleration standard values are all set as positive values, and the acceleration measurement values can be positive or negative values according to the direction of the coordinate axis to be measured. When calculating the indication error, the absolute values of the acceleration standard values and the acceleration measurement values are subtracted.

[0068] Therefore, in the embodiment, the inertial measurement unit is eccentrically installed on the worktable of the indexing device. When the eccentricity of the inertial measurement unit is constant, the main shaft is controlled to rotate at a first rotating speed to make the inertial measurement unit generate a centripetal acceleration, which is the acceleration standard value. Different acceleration standard values can be obtained by changing the eccentricity or the first rotating speed. Through the embodiment, a series of acceleration standard values can be set according to the range of the inertial measurement unit, the acceleration measurement values under each acceleration standard value are obtained, and calibration is performed, thereby improving the practicability of the calibration result.

[0069] It should be noted that before the calibration step in the application is performed on the inertial measurement unit, the zero drift of the inertial measurement unit needs to be detected. If the inertial measurement unit has obvious and disordered zero drift, it will not be further calibrated.

[0070] Further, in an embodiment, after step S14, the method further comprises:

[0071] When the inertial measurement unit is in the first installation state, the step of controlling the main shaft to rotate at the first rotating speed to obtain the acceleration measurement value of the coordinate axis to be measured is repeatedly performed.

[0072] According to the plurality of acceleration measurement values corresponding to the same first rotating speed, the repeatability error of the acceleration measurement value is calculated.

[0073] In the embodiment, the inertial measurement unit is repeatedly tested under the same test condition, and an acceleration measurement value is obtained each time. By comparing the plurality of acceleration measurement values under the same test condition, the repeatability error of the acceleration measurement value can be calculated. The repeatability error is further evaluated on the basis of the indication error, so as to improve the practicability of the calibration result. Specifically, the repeatability error is obtained through the variance or standard deviation of the plurality of acceleration measurement values.

[0074] Further, in an embodiment, after step S11, the method further comprises:

[0075] If the acceleration standard value is less than or equal to the gravitational acceleration, when the inertial measurement unit is in the second installation state, the flip angle is determined according to the acceleration standard value and the gravitational acceleration. When the inertial measurement unit is in the second installation state, the inertial measurement unit is centrally installed on the worktable, and the coordinate axis to be measured of the inertial measurement unit is collinear with the axis of the main shaft.

[0076] The pitch shaft connected with the main shaft is controlled to rotate to a position corresponding to the flip angle, and the acceleration measurement value of the coordinate axis to be measured is obtained.

[0077] Figure 4 Fig. 2 shows a schematic view of the inertial measurement unit in the second mounting state or the third mounting state according to an embodiment of the application.

[0078] The inertial measurement unit is capable of detecting the gravitational acceleration, which is used by the gravitational acceleration excitation inversion method mentioned in the background art. However, in the prior art, the inertial measurement unit is only arranged on the leveled platform in two attitudes of the positive direction of the coordinate axis to be measured and the downward direction, so that only two calibration points of g and -g can be calibrated.

[0079] With reference to Figure 4 In this embodiment, the indexing device 20 further comprises a pitch shaft 23 connected with the main shaft 22, the pitch shaft 23 is capable of driving the main shaft 22 to rotate to different angular positions, so that the workbench 21 connected with the main shaft 22 presents different degrees of inclination. When the inertial measurement unit 10 is in the second mounting state, the inertial measurement unit 10 is centrally mounted on the workbench 21, and the coordinate axis to be measured of the inertial measurement unit 10 is collinear with the axis of the main shaft 22. When the pitch shaft 23 is rotated to make the coordinate axis to be measured and the direction of gravity have a corresponding included angle, the component of the gravitational acceleration on the coordinate axis to be measured can be calculated according to the included angle. It can be understood that different components of the gravitational acceleration can be obtained by changing the inversion angle, so that any calibration point within the range of g and -g can be calibrated. The inversion angle is determined according to the acceleration standard value and the gravitational acceleration, and when the pitch shaft is rotated to the position corresponding to the inversion angle, the component of the gravitational acceleration on the coordinate axis to be measured is equal to the acceleration standard value. The inertial measurement unit 10 measures the acceleration measurement value of the corresponding coordinate axis to be measured.

[0080] Specifically, the step of determining the inversion angle according to the acceleration standard value and the gravitational acceleration comprises:

[0081] The acceleration standard value is substituted into the second formula to calculate the inversion angle, and the second formula is:

[0082]

[0083] Wherein, θ is the inversion angle, the inversion angle is the included angle between the coordinate axis to be measured and the direction of gravity, a is the acceleration standard value, and g is the gravitational acceleration.

[0084] In this embodiment, the inversion angle is the included angle between the coordinate axis to be measured and the direction of gravity, that is, the included angle between the axis of the main shaft and the direction of gravity. The angle of the pitch shaft to be controlled needs to be determined according to the position of the main shaft before rotation and the position corresponding to the inversion angle. For example, assuming that the axis of the main shaft is parallel to the direction of gravity before rotation, the angle of the pitch shaft to be rotated is equal to the inversion angle.

[0085] Further, in an embodiment, after the step S14, the method further comprises:

[0086] repeating the step of controlling the rotation of the pitch axis connected with the main shaft to the position corresponding to the flip angle to obtain the acceleration measurement value of the coordinate axis to be measured when the inertial measurement unit is in the second installation state;

[0087] According to the plurality of acceleration measurement values corresponding to the same flip angle, the repeatability error of the acceleration measurement value is calculated.

[0088] In this embodiment, the inertial measurement unit is repeatedly tested under the same test conditions, and each test obtains an acceleration measurement value. By comparing a plurality of acceleration measurement values under the same test conditions, the repeatability error of the acceleration measurement value can be calculated, and the repeatability error is further evaluated on the basis of the indication error to improve the practicability of the calibration result. Specifically, the repeatability error is obtained by the variance or standard deviation of a plurality of acceleration measurement values.

[0089] Further, in an embodiment, the inertial measurement unit calibration method further comprises:

[0090] determining an angular velocity standard value;

[0091] determining a second rotation speed according to the angular velocity standard value when the inertial measurement unit is in the third installation state, wherein when the inertial measurement unit is in the third installation state, the inertial measurement unit is centrally installed on the workbench, the coordinate axis to be measured of the inertial measurement unit is collinear with the axis of the main shaft, and the coordinate axis to be measured is parallel to the direction of gravity;

[0092] controlling the rotation of the main shaft at the second rotation speed to obtain an angular velocity measurement value of the coordinate axis to be measured;

[0093] calculating an indication error of the angular velocity measurement value according to the angular velocity standard value and the corresponding angular velocity measurement value.

[0094] Continuing to refer to Figure 4 In this embodiment, when the inertial measurement unit 10 is in the third installation state, the coordinate axis to be measured is further limited to be parallel to the direction of gravity on the basis of the second installation state. For the indexing device 20, it is necessary to ensure that the axis of the main shaft 22 is parallel to the direction of gravity. When the main shaft 22 rotates at a constant speed, the inertial measurement unit 10 also rotates synchronously at the same angular velocity. The second rotation speed can be converted from the set angular velocity standard value, so that when the main shaft 22 rotates at the second rotation speed, the angular velocity of the coordinate axis to be measured is equal to the angular velocity standard value. The inertial measurement unit 10 measures the corresponding angular velocity measurement value of the coordinate axis to be measured. The difference between the angular velocity standard value and the corresponding angular velocity measurement value is obtained to obtain the indication error of the angular velocity measurement value.

[0095] Further, after the step of calculating the indication error of the angular velocity measurement value according to the angular velocity standard value and the corresponding angular velocity measurement value, the method further comprises:

[0096] repeating the step of controlling the main shaft to rotate at the second rotating speed to obtain the angular velocity measurement value of the coordinate axis to be measured when the inertial measurement unit is in the third installation state;

[0097] calculating the repeatability error of the angular velocity measurement value according to the plurality of angular velocity measurement values corresponding to the same second rotating speed.

[0098] In the embodiment, the inertial measurement unit is repeatedly tested under the same test condition, and each test obtains an angular velocity measurement value. By comparing the plurality of angular velocity measurement values under the same test condition, the repeatability error of the angular velocity measurement value can be calculated. The repeatability error is further evaluated on the basis of the indication error to improve the practicability of the calibration result. Specifically, the repeatability error is obtained by the variance or standard deviation of the plurality of angular velocity measurement values.

[0099] In a second aspect, the embodiment of the present application further provides an inertial measurement unit calibration device.

[0100] In an embodiment, the inertial measurement unit calibration device comprises:

[0101] a standard module configured to determine an acceleration standard value;

[0102] a conversion module configured to obtain an eccentricity of the inertial measurement unit when the inertial measurement unit is in a first installation state, and determine a first rotating speed according to the acceleration standard value and the eccentricity, wherein when the inertial measurement unit is in the first installation state, the inertial measurement unit is eccentrically installed on a workbench of a rotating device, a coordinate axis to be measured of the inertial measurement unit is parallel to a radial direction of a main shaft connected with the workbench, and the coordinate axis to be measured is perpendicular to a direction of gravity;

[0103] an execution module configured to control the main shaft to rotate at the first rotating speed to obtain an acceleration measurement value of the coordinate axis to be measured;

[0104] an error module configured to calculate an indication error of the acceleration measurement value according to the acceleration standard value and the corresponding acceleration measurement value.

[0105] Further, in an embodiment, the step of determining the first rotating speed according to the acceleration standard value and the eccentricity in the conversion module comprises:

[0106] substituting the acceleration standard value and the eccentricity into a first formula to calculate the first rotating speed, and the first formula is:

[0107]

[0108] wherein n is the first rotating speed, a is the acceleration standard value, and r is the eccentricity.

[0109] Further, in an embodiment, the executing module is further configured to repeatedly perform the step of controlling the main shaft to rotate at the first rotating speed to obtain the acceleration measurement of the coordinate axis to be measured when the inertial measurement unit is in the first installation state.

[0110] The error module is further configured to calculate the repeatability error of the acceleration measurement according to the plurality of acceleration measurements corresponding to the same first rotating speed.

[0111] Further, in an embodiment, the converting module is further configured to, if the acceleration standard value is less than or equal to the gravitational acceleration, determine the flip angle according to the acceleration standard value and the gravitational acceleration when the inertial measurement unit is in the second installation state, wherein the inertial measurement unit is installed on the workbench in a vertical state when the inertial measurement unit is in the second installation state, and the coordinate axis to be measured of the inertial measurement unit is collinear with the axis of the main shaft.

[0112] The executing module is further configured to control the pitch shaft connected with the main shaft to rotate to a position corresponding to the flip angle to obtain the acceleration measurement of the coordinate axis to be measured.

[0113] Further, in an embodiment, the step of determining the flip angle according to the acceleration standard value and the gravitational acceleration in the converting module comprises:

[0114] substituting the acceleration standard value into the second formula to calculate the flip angle, the second formula being:

[0115]

[0116] wherein θ is the flip angle, the flip angle being an angle between the coordinate axis to be measured and the direction of gravity, a is the acceleration standard value, and g is the gravitational acceleration.

[0117] Further, in an embodiment, the executing module is further configured to repeatedly perform the step of controlling the pitch shaft connected with the main shaft to rotate to a position corresponding to the flip angle to obtain the acceleration measurement of the coordinate axis to be measured when the inertial measurement unit is in the second installation state.

[0118] The error module is further configured to calculate the repeatability error of the acceleration measurement according to the plurality of acceleration measurements corresponding to the same flip angle.

[0119] Further, in an embodiment, the standard module is further configured to determine an angular velocity standard value.

[0120] The converting module is further configured to determine the second rotating speed according to the angular velocity standard value when the inertial measurement unit is in the third installation state, wherein the inertial measurement unit is installed on the workbench in a vertical state when the inertial measurement unit is in the third installation state, the coordinate axis to be measured of the inertial measurement unit is collinear with the axis of the main shaft, and the coordinate axis to be measured is parallel to the direction of gravity.

[0121] The execution module is further configured to control the main shaft to rotate at a second rotating speed, and obtain an angular velocity measurement value of the coordinate axis to be measured.

[0122] The error module is further configured to calculate an indication error of the angular velocity measurement value according to the angular velocity standard value and the corresponding angular velocity measurement value.

[0123] Further, in an embodiment, the execution module is further configured to repeat the steps of controlling the main shaft to rotate at the second rotating speed and obtaining the angular velocity measurement value of the coordinate axis to be measured when the inertial measurement unit is in the third installation state.

[0124] The error module is further configured to calculate a repeatability error of the angular velocity measurement value according to a plurality of angular velocity measurement values corresponding to the same second rotating speed.

[0125] The functions of each module in the inertial measurement unit calibration device correspond to the steps in the inertial measurement unit calibration method, and the functions and implementation processes will not be repeated here.

[0126] In a third aspect, an embodiment of the present application provides an inertial measurement unit calibration device, which can be a personal computer (PC), a notebook computer, a server, or other device with data processing function.

[0127] Figure 5 A hardware structure diagram of the inertial measurement unit calibration device in an embodiment of the present application is shown.

[0128] Referring to Figure 5 In an embodiment of the present application, the inertial measurement unit calibration device can include a processor 1001 (such as a central processing unit (CPU)), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. The communication bus 1002 is used to realize the connection and communication between these components; the user interface 1003 can include a display and an input unit such as a keyboard; the network interface 1004 can optionally include a standard wired interface and a wireless interface (such as a wireless fidelity (WI-FI) interface); the memory 1005 can be a high-speed random access memory (RAM) and can also be a stable memory (non-volatile memory) such as a disk memory; the memory 1005 can optionally be a storage device independent of the aforementioned processor 1001. Those skilled in the art can understand that Figure 5The hardware structure shown in the foregoing embodiments is not a limitation on the present application, and can include more or fewer components than shown, or combine certain components, or arrange the components differently.

[0129] With reference to the foregoing description of the hardware structure, the processor 1001 can execute the inertial measurement unit calibration program stored in the memory 1005 to implement the embodiments of the present application. Figure 5 , Figure 5 The memory 1005 in the foregoing embodiments can include an operating system, a network communication module, a user interface module, and an inertial measurement unit calibration program. The processor 1001 can invoke the inertial measurement unit calibration program stored in the memory 1005 and execute the inertial measurement unit calibration method provided by the embodiments of the present application.

[0130] It should be noted that the terms "comprising", "including", or any other variant thereof in the present document are intended to cover a non-exclusive inclusion, so that a process, method, article, or system that includes a list of elements not only includes those elements, but also includes other elements not expressly listed or inherent to such process, method, article, or system. Without more limitations, an element defined by the phrase "comprising a" does not exclude the presence of additional identical elements in the process, method, article, or system that includes the element.

[0131] The above-mentioned embodiment numbers of the present application are only for description, and do not represent the advantages or disadvantages of the embodiments.

[0132] From the above description of the embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software and the necessary general hardware platform, of course, they can also be implemented by hardware, but in many cases the former is a better embodiment. Based on such understanding, the technical solutions of the present application can be embodied in the form of a software product, which is stored in a storage medium (such as a ROM / RAM, a magnetic disk, an optical disk) as described above, and includes a plurality of instructions for causing a terminal device to execute the methods described in the embodiments of the present application.

[0133] The above is only the preferred embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent process transformation made by using the contents of the present application specification and drawings, or directly or indirectly applied to other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A calibration method for an inertial measurement unit, characterized in that, The inertial measurement unit calibration method includes: Determine the standard value of acceleration; When the inertial measurement unit is in the first installation state, the eccentricity of the inertial measurement unit is obtained, and the first rotational speed is determined according to the acceleration standard value and the eccentricity. When the inertial measurement unit is in the first installation state, the inertial measurement unit is eccentrically installed on the worktable of the indexing device, the coordinate axis to be measured of the inertial measurement unit is parallel to the radial direction of the main shaft connected to the worktable, and the coordinate axis to be measured is perpendicular to the direction of gravity. Control the spindle to rotate at the first rotational speed to obtain the acceleration measurement value of the coordinate axis to be measured; If the acceleration standard value is less than or equal to the gravitational acceleration, then when the inertial measurement unit is in the second installation state, the flip angle is determined according to the acceleration standard value and the gravitational acceleration. In the second installation state, the inertial measurement unit is centered on the worktable, and the coordinate axis to be measured of the inertial measurement unit is collinear with the axis of the main spindle. Control the pitch axis connected to the main axis to rotate to the position corresponding to the flip angle, and obtain the acceleration measurement value of the coordinate axis to be measured; The indication error of the acceleration measurement value is calculated based on the standard acceleration value and the corresponding acceleration measurement value.

2. The inertial measurement unit calibration method as described in claim 1, characterized in that, The step of determining the first rotational speed based on the acceleration standard value and the eccentricity includes: Substituting the standard value of acceleration and the eccentricity into the first formula, the first rotational speed is calculated. The first formula is: Where n is the first rotational speed, a is the standard value of acceleration, and r is the eccentricity.

3. The inertial measurement unit calibration method as described in claim 1, characterized in that, After the step of calculating the indication error of the acceleration measurement value based on the acceleration standard value and the corresponding acceleration measurement value, the method further includes: When the inertial measurement unit is in the first installation state, the step of controlling the main shaft to rotate at the first speed and obtaining the acceleration measurement value of the coordinate axis to be measured is repeated. The repeatability error of the acceleration measurement value is calculated based on multiple acceleration measurements corresponding to the same first rotational speed.

4. The inertial measurement unit calibration method as described in claim 1, characterized in that, The step of determining the roll angle based on the acceleration standard value and gravitational acceleration includes: Substituting the standard value of acceleration into the second formula, the roll angle is calculated. The second formula is: in, The flip angle is the angle between the coordinate axis to be measured and the direction of gravity, α is the standard value of acceleration, and g is the gravitational acceleration.

5. The inertial measurement unit calibration method as described in claim 1, characterized in that, After the step of calculating the indication error of the acceleration measurement value based on the acceleration standard value and the corresponding acceleration measurement value, the method further includes: When the inertial measurement unit is in the second installation state, the step of controlling the pitch axis connected to the main shaft to rotate to the position corresponding to the flip angle is repeated to obtain the acceleration measurement value of the coordinate axis to be measured. The repeatability error of the acceleration measurement value is calculated based on multiple acceleration measurements corresponding to the same flip angle.

6. The inertial measurement unit calibration method according to any one of claims 1 to 5, characterized in that, The inertial measurement unit calibration method further includes: Determine the standard value of angular velocity; When the inertial measurement unit is in the third installation state, the second rotational speed is determined according to the standard value of the angular velocity. When the inertial measurement unit is in the third installation state, the inertial measurement unit is centered on the worktable, the coordinate axis to be measured of the inertial measurement unit is collinear with the axis of the main spindle, and the coordinate axis to be measured is parallel to the direction of gravity. The spindle is controlled to rotate at the second rotation speed to obtain the angular velocity measurement value of the coordinate axis to be measured; The indication error of the angular velocity measurement value is calculated based on the standard value of the angular velocity and the corresponding measured value of the angular velocity.

7. The inertial measurement unit calibration method as described in claim 6, characterized in that, After the step of calculating the indication error of the angular velocity measurement value based on the standard angular velocity value and the corresponding angular velocity measurement value, the method further includes: When the inertial measurement unit is in the third installation state, the step of controlling the spindle to rotate at the second rotation speed and obtaining the angular velocity measurement value of the coordinate axis to be measured is repeated. The repeatability error of the angular velocity measurement value is calculated based on multiple angular velocity measurements corresponding to the same second rotational speed.

8. An inertial measurement unit calibration device, characterized in that, The inertial measurement unit calibration device includes: A standard module is used to determine the standard value of acceleration; The conversion module is used to obtain the eccentricity of the inertial measurement unit when the inertial measurement unit is in the first installation state if the acceleration standard value is greater than the gravitational acceleration, and to determine the first rotational speed based on the acceleration standard value and the eccentricity. When the inertial measurement unit is in the first installation state, the inertial measurement unit is eccentrically mounted on the worktable of the indexing device, the coordinate axis to be measured of the inertial measurement unit is parallel to the radial direction of the main shaft connected to the worktable, and the coordinate axis to be measured is perpendicular to the direction of gravity. An execution module is used to control the spindle to rotate at the first rotational speed to obtain the acceleration measurement value of the coordinate axis to be measured; An error module is used to calculate the indication error of the acceleration measurement value based on the acceleration standard value and the corresponding acceleration measurement value. The conversion module is also used to determine the flip angle based on the acceleration standard value and the gravitational acceleration when the inertial measurement unit is in the second installation state if the acceleration standard value is less than or equal to the gravitational acceleration. In the second installation state, the inertial measurement unit is centered on the worktable and the coordinate axis to be measured of the inertial measurement unit is collinear with the axis of the main spindle. The execution module is also used to control the pitch axis connected to the main shaft to rotate to the position corresponding to the flip angle, and to obtain the acceleration measurement value of the coordinate axis to be measured.

9. An inertial measurement unit calibration device, characterized in that, The inertial measurement unit calibration device includes a processor, a memory, and an inertial measurement unit calibration program stored in the memory and executable by the processor, wherein when the inertial measurement unit calibration program is executed by the processor, it implements the steps of the inertial measurement unit calibration method as described in any one of claims 1 to 7.

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