Inertial measurement unit temperature comprehensive compensation method

Abstract

The invention provides a comprehensive temperature compensation method for an inertial measurement unit, which comprises the following steps of: respectively designing a three-axis gyroscope full-temperature comprehensive compensation model and a three-axis accelerometer full-temperature comprehensive compensation model of the inertial measurement unit; on the basis, comprehensive compensation parameter calibration of the three-axis gyroscope and comprehensive compensation parameter calibration of the three-axis accelerometer are performed respectively, and finally, an angular velocity and acceleration output equation of the inertial measurement unit after comprehensive compensation is obtained, so that the measurement precision of the inertial measurement unit is improved.

Description

Technical Field

[0001] This invention belongs to the field of inertial sensor technology and relates to a method for comprehensive temperature compensation of an inertial measurement unit. Background Technology

[0002] An inertial measurement unit (IMU) typically consists of a triaxial gyroscope and a triaxial accelerometer. Temperature-related errors during operation primarily include gyroscope zero-point temperature drift and gyroscope scale factor temperature drift, as well as accelerometer zero-point temperature drift and accelerometer scale factor temperature drift. These errors directly affect the IMU's measurement accuracy. Furthermore, during the IMU's manufacturing process, due to manufacturing and assembly errors, the actual coordinate system of the IMU's output axes may not coincide with the system's ideal coordinate system; that is, the axes are not perfectly orthogonal. This leads to mutual coupling between the output values ​​of the IMU's axes, ultimately resulting in installation coupling errors that affect measurement accuracy. Because of the differences in internal temperature and the coefficients of thermal expansion of various materials within the IMU, the installation error angle changes with temperature, causing installation coupling errors to vary with temperature. Additionally, if the gyroscope and accelerometer themselves have poor scaling factor nonlinearity, and this nonlinearity changes drastically with temperature, it will also introduce significant measurement errors. The current compensation methods for the various errors caused by the temperature are relatively simple, only compensating for a few items at full temperature or compensating for a few items at a certain temperature point. Moreover, the compensation calibration of a certain item is often performed first before the subsequent compensation calibration steps can be carried out, which is a rather cumbersome process. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0004] Therefore, the present invention provides a comprehensive temperature compensation method for inertial measurement units. This compensation method takes into account all error terms affected by temperature, and comprehensively compensates for each error at once to obtain accurate angular velocity and acceleration output equations for the inertial measurement unit, thereby improving measurement accuracy and simplifying the process.

[0005] The technical solution of the present invention is as follows: A comprehensive temperature compensation method for an inertial measurement unit is provided, the comprehensive temperature compensation method comprising...

[0006] The operating temperature range of the inertial measurement unit is divided into a series of temperature intervals, and a series of temperature points (T1, T2…T) are generated using the endpoints of these intervals. n );

[0007] The comprehensive compensation parameters of the three-axis gyroscope are calibrated based on the aforementioned series of temperature points, including:

[0008] 1) Place the inertial measurement unit in a temperature chamber with a dual-axis turntable. Set the temperature chamber input to a series of temperature points (T1, T2…T…). n-1 ,T n ,T n-1 …T2,T1), the turntable input is set to a series of angular velocity points (±ω1,±ω2…±ω). n );

[0009] 2) The three gyroscope sensing axes are calibrated along the rotation axis of the turntable as follows:

[0010] Make the temperature chamber operate according to the set input temperature points (T1, T2…T…). n-1 ,T n ,T n-1 …T2,T1) operation, for each temperature point: after holding at each temperature point for a preset time, the turntable is made to run at the set angular velocity point (±ω1,±ω2…±ω). n The system rotates, and during the rotation, the output data of the three-axis gyroscope of the inertial measurement unit is collected and recorded; the data collected at the same temperature point are averaged.

[0011] 3) Temperature compensation is performed based on the designed three-axis gyroscope integrated compensation model and the data obtained in step 2);

[0012] The comprehensive compensation parameter calibration of the triaxial accelerometer is performed based on the aforementioned series of temperature points, including:

[0013] 11) Place the inertial measurement unit in an incubator equipped with a centrifuge. Set the incubator input to a series of temperature points (T1, T2…T…). n-1 ,T n ,T n-1 …T2,T1), the centrifuge input is set to a series of acceleration points (a1,a2…a…). n );

[0014] 12) The three accelerometer sensing axes were calibrated sequentially along the centrifugal axis and in the opposite direction as follows:

[0015] Make the temperature chamber operate according to the set input temperature points (T1, T2…T…). n-1 ,T n ,T n-1 …T2,T1) operation, for each temperature point: after holding at each temperature point for a preset time, the centrifuge is made to accelerate to the set acceleration point (a1,a2…a…). n The system rotates, and during this rotation, the output data of the triaxial accelerometer of the inertial measurement unit is collected and recorded. The acceleration data in the reverse direction is calculated according to -a1, -a2…-a… n To record; average the data collected at the same temperature points;

[0016] 13) Temperature compensation is performed based on the designed triaxial accelerometer integrated compensation model and the data obtained in step 12).

[0017] Furthermore, step 3) specifically includes:

[0018] Based on the designed three-axis gyroscope comprehensive compensation model, the collected data is used to generate compensation parameters for the corresponding insulation temperature point.

[0019] Repeat step 2) of data acquisition and compensation parameter generation at all temperature points until the last temperature point is set.

[0020] After obtaining the comprehensive compensation parameters for all temperature points, the relationship between the comprehensive compensation parameters of the three-axis gyroscope and temperature is fitted. The compensation parameters are then substituted into the comprehensive compensation model of the three-axis gyroscope to finally obtain the angular velocity output equation of the inertial measurement unit.

[0021] Furthermore, the designed three-axis gyroscope comprehensive compensation model is shown in the following equation:

[0022]

[0023] In the formula:

[0024] ω x ,ω y ,ω z These are the true angular velocities of the inertial measurement unit along the x, y, and z axes, respectively.

[0025] ω sx ,ω sy ,ω sz These are the output values ​​of the three-axis gyroscope of the inertial measurement unit along the x, y, and z axes, respectively.

[0026] T represents the real-time temperature inside the inertial measurement unit;

[0027] k mij (T) is the m-th term coupling coefficient of the j-axis output value of the three-axis gyroscope of the inertial measurement unit to the true angular rate of the i-axis, which is a parameter that varies with temperature T;

[0028] u 0x (T),u 0y (T),u 0z (T) represents the equivalent zero bias of the x, y, and z axes of the three-axis gyroscope in the inertial measurement unit, and is a parameter that varies with temperature T.

[0029] Furthermore, in step 3), the comprehensive compensation parameters for all temperature points are obtained in the following manner:

[0030] a. At a certain temperature, when the inertial measurement unit's x-axis is calibrated, the true angular velocity of the x-axis is the turntable's set angular velocity value, while the true angular velocities of the other two axes remain 0. Therefore, the following relationship is obtained:

[0031]

[0032] The relation is considered as having the independent variable as... ω sx ,ω sy ,ω sz 1, with ω as the dependent variable. x The functional relationship is derived, and a dataset is collected using a series of angular velocity points at this temperature. Using linear regression, the parameter k at the current temperature is obtained by fitting the data. 3xx ,k 3xy ,k 3xz ,k 2xx ,k 2xy ,k 2xz ,k 1xx ,k 1xy ,k 1xz ,u 0x ;

[0033] b. Using the same method as in step a, other parameters in the model at the same temperature can be obtained, as shown below:

[0034] k 3yx ,k 3yy ,k 3yz ,k 2yx ,k 2yy ,k 2yz ,k 1yx ,k 1yy ,k 1yz ,u 0y

[0035] k 3zx ,k 3zy ,k 3zz ,k 2zx ,k 2zy ,k 2zz ,k 1zx ,k 1zy ,k 1zz ,u 0z

[0036] c. Change the temperature to a series of temperature points n = T1, T2…T n-1 ,T n ,T n-1 …T2,T1, and the comprehensive compensation parameters for the corresponding temperature points can be obtained, as shown below:

[0037] k3xx (n),k 3xy (n),k 3xz (n),k 2xx (n),k 2xy (n),k 2xz (n),k 1xx (n),k 1xy (n),k 1xz (n),u 0x (n)

[0038] k 3yx (n),k 3yy (n),k 3yz (n),k 2yx (n),k 2yy (n),k 2yz (n),k 1yx (n),k 1yy (n),k 1yz (n),u 0y (n)

[0039] k 3zx (n),k 3zy (n),k 3zz (n),k 2zx (n),k 2zy (n),k 2zz (n),k 1zx (n),k 1zy (n),k 1zz (n),u 0z (n).

[0040] Further, in step 3), each parameter sequence k mij (n),u 0x (n),u 0y (n),u 0z (n) respectively fits a polynomial relationship with the sequence n, thus obtaining the functional relationship between the comprehensive compensation parameters in the model and temperature:

[0041] k 3xx (T),k 3xy (T),k 3xz (T),k 2xx (T),k 2xy (T),k 2xz (T),k 1xx (T),k 1xy (T),k 1xz (T),u 0x (T)

[0042] k 3yx (T),k 3yy(T),k 3yz (T),k 2yx (T),k 2yy (T),k 2yz (T),k 1yx (T),k 1yy (T),k 1yz (T),u 0y (T)

[0043] k 3zx (T),k 3zy (T),k 3zz (T),k 2zx (T),k 2zy (T),k 2zz (T),k 1zx (T),k 1zy (T),k 1zz (T),u 0z (T)

[0044] Substituting the comprehensive compensation parameters into the three-axis gyroscope comprehensive compensation model yields the angular velocity output equation of the inertial measurement unit.

[0045] Furthermore, step 13) specifically includes:

[0046] Based on the designed triaxial accelerometer integrated compensation model, the collected data is used to generate compensation parameters for the corresponding insulation temperature points.

[0047] Repeat step 12) for data acquisition and compensation parameter generation at all temperature points until the last temperature point is set.

[0048] After obtaining the comprehensive compensation parameters for all temperature points, the relationship between the comprehensive compensation parameters of the triaxial accelerometer and temperature is fitted. The compensation parameters are then substituted into the comprehensive compensation model of the triaxial accelerometer to finally obtain the acceleration output equation of the inertial measurement unit.

[0049] Furthermore, in step 13), the designed triaxial accelerometer integrated compensation model is shown in the following equation:

[0050]

[0051] In the formula:

[0052] a x ,a y ,a z These are the actual accelerations of the inertial measurement unit along the x, y, and z axes, respectively.

[0053] a sx ,a sy ,a szThese are the output values ​​of the three-axis accelerometer of the inertial measurement unit along the x, y, and z axes, respectively.

[0054] T represents the real-time temperature inside the inertial measurement unit;

[0055] l mij (T) is the m-th term coupling coefficient between the j-axis output value of the triaxial accelerometer of the measurement unit and the actual acceleration of the i-axis, and is a parameter that varies with temperature T.

[0056] m 0x (T),m 0y (T),m 0z (T) represents the equivalent zero bias of the x, y, and z axes of the triaxial accelerometer in the inertial measurement unit, and is a parameter that varies with temperature T.

[0057] Furthermore, in step 13), the same calculation method as for the comprehensive supplementary parameters of the triaxial gyroscope is used to obtain the functional relationship between the comprehensive compensation parameters and temperature in the triaxial accelerometer model:

[0058] l 3xx (T),l 3xy (T),l 3xz (T),l 2xx (T),l 2xy (T),l 2xz (T),l 1xx (T),l 1xy (T),l 1xz (T),m 0x (T)

[0059] l 3yx (T),l 3yy (T),l 3yz (T),l 2yx (T),l 2yy (T),l 2yz (T),l 1yx (T),l 1yy (T),l 1yz (T),m 0y (T)

[0060] l 3zx (T),l 3zy (T),l 3zz (T),l 2zx (T),l 2zy (T),l 2zz (T),l 1zx (T),l 1zy (T),l 1zz (T),m 0z (T)

[0061] Substituting the obtained comprehensive compensation parameters into the triaxial accelerometer comprehensive compensation model yields the acceleration output equation of the inertial measurement unit.

[0062] Applying the above technical solution, a comprehensive temperature compensation method for inertial measurement units (IMUs) is provided. This method designs comprehensive temperature compensation models for the three-axis gyroscope and the three-axis accelerometer, respectively. Specifically, it comprehensively compensates for the temperature drift of the three-axis gyroscope zero point and scale factor caused by the temperature of the IMU, the temperature drift of the three-axis accelerometer zero point and scale factor, the coupling error of the three-axis gyroscope and the coupling error of the three-axis accelerometer, as well as the nonlinearity of the three-axis gyroscope and the nonlinearity of the three-axis accelerometer. Finally, it obtains the comprehensive compensation output equations of the angular velocity and acceleration of the IMU, effectively improving the measurement accuracy of the IMU. Attached Figure Description

[0063] The accompanying drawings, which form part of this specification, are provided to further illustrate embodiments of the invention and, together with the textual description, explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0064] Figure 1 This is a flowchart of the calibration process for the comprehensive temperature compensation method of an inertial measurement unit and the comprehensive compensation parameters of a three-axis gyroscope.

[0065] Figure 2 This is a flowchart of a method for comprehensive temperature compensation of inertial measurement units and calibration of comprehensive compensation parameters for triaxial accelerometers. Detailed Implementation

[0066] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0067] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0068] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0069] like Figure 1-2 As shown, in one embodiment of the present invention, the technical solution of the present invention is as follows: A method for comprehensive temperature compensation of an inertial measurement unit is provided, the method comprising...

[0070] The operating temperature range of the inertial measurement unit is divided into a series of temperature intervals, and a series of temperature points (T1, T2…T) are generated using the endpoints of these intervals. n );

[0071] The comprehensive compensation parameters of the three-axis gyroscope are calibrated based on the aforementioned series of temperature points, including:

[0072] 1) Place the inertial measurement unit in a temperature chamber with a dual-axis turntable. Set the temperature chamber input to a series of temperature points (T1, T2…T…). n-1 ,T n ,T n-1 …T2,T1), the turntable input is set to a series of angular velocity points (±ω1,±ω2…±ω). n );

[0073] 2) The three gyroscope sensing axes are calibrated along the rotation axis of the turntable as follows:

[0074] Make the temperature chamber operate according to the set input temperature points (T1, T2…T…). n-1 ,T n ,Tn-1 …T2,T1) operation, for each temperature point: after holding at each temperature point for a preset time, the turntable is made to run at the set angular velocity point (±ω1,±ω2…±ω). n The system rotates, and during the rotation, the output data of the three-axis gyroscope of the inertial measurement unit is collected and recorded; the data collected at the same temperature point are averaged.

[0075] 3) Temperature compensation is performed based on the designed three-axis gyroscope integrated compensation model and the data obtained in step 2);

[0076] The comprehensive compensation parameter calibration of the triaxial accelerometer is performed based on the aforementioned series of temperature points, including:

[0077] 11) Place the inertial measurement unit in an incubator equipped with a centrifuge. Set the incubator input to a series of temperature points (T1, T2…T…). n-1 ,T n ,T n-1 …T2,T1), the centrifuge input is set to a series of acceleration points (a1,a2…a…). n );

[0078] 12) The three accelerometer sensing axes were calibrated sequentially along the centrifugal axis and in the opposite direction as follows:

[0079] Make the temperature chamber operate according to the set input temperature points (T1, T2…T…). n-1 ,T n ,T n-1 …T2,T1) operation, for each temperature point: after holding at each temperature point for a preset time, the centrifuge is made to accelerate to the set acceleration point (a1,a2…a…). n The system rotates, and during this rotation, the output data of the triaxial accelerometer of the inertial measurement unit is collected and recorded. The acceleration data in the reverse direction is calculated according to -a1, -a2…-a… n To record; average the data collected at the same temperature points;

[0080] 13) Temperature compensation is performed based on the designed triaxial accelerometer integrated compensation model and the data obtained in step 12).

[0081] That is, the method of the present invention mainly includes temperature comprehensive compensation of the three-axis gyroscope and temperature comprehensive compensation of the three-axis accelerometer, and the compensation parameters need to be calibrated separately.

[0082] Specifically, for the comprehensive temperature compensation of a three-axis gyroscope, such as Figure 1 As shown, the inertial measurement unit is first placed in a temperature chamber with a dual-axis turntable, so that the temperature chamber is set according to the input temperature points (T1, T2…T…). n-1 ,T n ,Tn-1 …T2,T1) operation, after holding at each temperature point for a certain period of time, the turntable is made to run at the set angular velocity points (±ω1,±ω2…±ω). n The inertial measurement unit (IMU) rotates, and during this rotation, the output data of the three-axis gyroscope is collected and recorded. This data collection process is performed sequentially on the three sensitive axes of the gyroscope. Then, based on the designed comprehensive compensation model of the three-axis gyroscope, compensation parameters for the corresponding insulation temperature points are generated using the collected data. This data collection and compensation parameter generation process is repeated at all temperature points until the last set temperature point. Finally, after obtaining the comprehensive compensation parameters for all temperature points, the relationship between the comprehensive compensation parameters of the three-axis gyroscope and temperature is fitted. These compensation parameters are then substituted into the comprehensive compensation model of the three-axis gyroscope to finally obtain the angular velocity output equation of the IMU.

[0083] For triaxial accelerometer comprehensive compensation, such as Figure 2 As shown, the inertial measurement unit is first placed in a temperature chamber equipped with a centrifuge, and the temperature chamber is set according to the input temperature points (T1, T2…T…). n-1 ,T n ,T n-1 …T2,T1) are run, and after holding at each temperature point for a certain period of time, the centrifuge is accelerated to the set acceleration points (a1,a2…a…). n The system operates by collecting and recording the output data of the triaxial accelerometer of the inertial measurement unit (IMU). Then, the sensitive axes are reversed, and the system runs again at the set acceleration point, collecting negative direction output data. This data acquisition process is repeated sequentially across the three sensitive axes of the gyroscope. Based on the designed triaxial accelerometer comprehensive compensation model, the collected data is used to generate compensation parameters for the corresponding insulation temperature points. This data acquisition and compensation parameter generation process is repeated at all temperature points until the last set temperature point. Finally, after obtaining the comprehensive compensation parameters for all temperature points, the relationship between the triaxial accelerometer comprehensive compensation parameters and temperature is fitted. These compensation parameters are then substituted into the triaxial accelerometer comprehensive compensation model to obtain the final acceleration output equation of the IMU.

[0084] As can be seen, the embodiments of the present invention first follow the calibration process of the inertial measurement unit's three-axis gyroscope and three-axis accelerometer parameters to collect data, then use the collected data to fit the relationship between the comprehensive compensation parameters and temperature based on the designed comprehensive compensation model, and finally substitute the relationship into the comprehensive compensation model to obtain the angular velocity and acceleration output equations of the inertial measurement unit after temperature comprehensive compensation.

[0085] In the above embodiment, the three-axis gyroscope comprehensive compensation model is as follows:

[0086]

[0087] In the formula:

[0088] ω x ,ω y ,ω z —These are the true angular velocities of the inertial measurement unit along the x, y, and z axes, respectively;

[0089] ω sx ,ω sy ,ω sz —These are the output values ​​of the three-axis gyroscope of the inertial measurement unit along the x, y, and z axes, respectively;

[0090] T represents the real-time temperature inside the inertial measurement unit.

[0091] k mij (T)——The m-th term coupling coefficient of the j-axis output value of the three-axis gyroscope of the inertial measurement unit to the true angular rate of the i-axis, which is a parameter that varies with temperature T.

[0092] u 0x (T),u 0y (T),u 0z (T)——The equivalent zero bias of the x, y, and z axes of the three-axis gyroscope in the inertial measurement unit is a parameter that varies with temperature T.

[0093] Specifically:

[0094] At a certain temperature, when the inertial measurement unit is calibrated along the x-axis, the true angular velocity of the x-axis is the turntable's set angular velocity value, while the true angular velocities of the other two axes remain 0. Therefore, taking the first equation above, we have the following relationship:

[0095] The independent variable is ω sx ,ω sy ,ω sz 1, with ω as the dependent variable. x The functional relationship is obtained by collecting a dataset of angular velocity points at this temperature. Using linear regression, the parameters at the current temperature are obtained by fitting the data.

[0096] k 3xx ,k 3xy ,k 3xz ,k 2xx ,k 2xy ,k 2xz ,k 1xx ,k 1xy ,k 1xz ,u 0x

[0097] The same method can be used to obtain other parameters in the model at the same temperature:

[0098] k 3yx ,k 3yy ,k 3yz ,k 2yx ,k 2yy ,k 2yz ,k 1yx ,k 1yy ,k 1yz ,u 0y

[0099] k 3zx ,k 3zy ,k 3zz ,k 2zx ,k 2zy ,k 2zz ,k 1zx ,k 1zy ,k 1zz ,u 0z

[0100] From this point on, all the comprehensive compensation parameters of the model at this temperature can be obtained. If the temperature is changed to a series of temperature points n = T1, T2…T… n-1 ,T n ,T n-1 …T2,T1, then the comprehensive compensation parameters for the corresponding temperature points can be obtained:

[0101] k 3xx (n),k 3xy (n),k 3xz (n),k 2xx (n),k 2xy (n),k 2xz (n),k 1xx (n),k 1xy (n),k 1xz (n),u 0x (n)

[0102] k 3yx (n),k 3yy (n),k 3yz (n),k 2yx (n),k 2yy (n),k 2yz (n),k 1yx (n),k 1yy (n),k 1yz (n),u 0y (n)

[0103] k 3zx (n),k 3zy (n),k 3zz (n),k 2zx (n),k 2zy (n),k 2zz(n),k 1zx (n),k 1zy (n),k 1zz (n),u 0z (n)

[0104] In the above formula, each parameter sequence k mij (n),u 0x (n),u 0y (n),u 0z (n) respectively fits a polynomial relationship with the sequence n, thus obtaining the functional relationship between the comprehensive compensation parameters in the model and temperature:

[0105] k 3xx (T),k 3xy (T),k 3xz (T),k 2xx (T),k 2xy (T),k 2xz (T),k 1xx (T),k 1xy (T),k 1xz (T),u 0x (T)

[0106] k 3yx (T),k 3yy (T),k 3yz (T),k 2yx (T),k 2yy (T),k 2yz (T),k 1yx (T),k 1yy (T),k 1yz (T),u 0y (T)

[0107] k 3zx (T),k 3zy (T),k 3zz (T),k 2zx (T),k 2zy (T),k 2zz (T),k 1zx (T),k 1zy (T),k 1zz (T),u 0z (T)

[0108] Substituting the above comprehensive compensation parameters into the three-axis gyroscope comprehensive compensation model yields the angular velocity output equation of the inertial measurement unit.

[0109] In the above embodiment, the triaxial accelerometer comprehensive compensation model is as follows:

[0110]

[0111] In the formula:

[0112] a x ,a y ,a z —These are the actual accelerations of the inertial measurement unit along the x, y, and z axes, respectively;

[0113] a sx ,a sy ,a sz —These are the output values ​​of the three-axis accelerometer of the inertial measurement unit along the x, y, and z axes, respectively;

[0114] T represents the real-time temperature inside the inertial measurement unit.

[0115] l mij (T)——The coupling coefficient of the m-th term of the j-axis output value of the triaxial accelerometer of the inertial measurement unit to the actual acceleration of the i-axis, which is a parameter that varies with temperature T.

[0116] m 0x (T),m 0y (T),m 0z (T)——The equivalent zero bias of the x, y, and z axes of the triaxial accelerometer of the inertial measurement unit, which is a parameter that varies with temperature T.

[0117] Using the same method for calculating the integrated parameters of a three-axis gyroscope, the functional relationship between the integrated compensation parameters and temperature in the three-axis accelerometer model can be obtained:

[0118] l 3xx (T),l 3xy (T),l 3xz (T),l 2xx (T),l 2xy (T),l 2xz (T),l 1xx (T),l 1xy (T),l 1xz (T),m 0x (T)

[0119] l 3yx (T),l 3yy (T),l 3yz (T),l 2yx (T),l 2yy (T),l 2yz (T),l 1yx (T),l 1yy (T),l 1yz (T),m 0y (T)

[0120] l 3zx (T),l3zy (T),l 3zz (T),l 2zx (T),l 2zy (T),l 2zz (T),l 1zx (T),l 1zy (T),l 1zz (T),m 0z (T)

[0121] Substituting the above comprehensive compensation parameters into the triaxial accelerometer comprehensive compensation model yields the acceleration output equation of the inertial measurement unit.

[0122] In summary, this invention provides a comprehensive temperature compensation method for an inertial measurement unit (IMU). This method designs comprehensive temperature compensation models for both the three-axis gyroscope and the three-axis accelerometer, specifically compensating for the temperature-induced zero-point temperature drift of the three-axis gyroscope, the temperature drift of the three-axis accelerometer, the temperature drift of the accelerometer's scale factor, the coupling error of the three-axis gyroscope, the coupling error of the three-axis accelerometer, and the nonlinearity of the three-axis gyroscope and the nonlinearity of the three-axis accelerometer. Ultimately, the compensated angular velocity and acceleration output equations of the IMU are obtained, effectively improving the measurement accuracy of the IMU.

[0123] The features described and / or illustrated above with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, and / or in combination with or in lieu of features in other embodiments.

[0124] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, components, or combinations thereof.

[0125] The methods described above in this invention can be implemented in hardware or in combination with software. This invention relates to computer-readable programs that, when executed by a logic component, enable the logic component to implement the aforementioned apparatus or constituent parts, or to implement the various methods or steps described above. This invention also relates to storage media for storing the above programs, such as hard disks, magnetic disks, optical disks, DVDs, flash memory, etc.

[0126] Many features and advantages of these embodiments are apparent from this detailed description, and therefore the appended claims are intended to cover all such features and advantages of these embodiments that fall within their true spirit and scope. Furthermore, since many modifications and alterations will readily occur to those skilled in the art, the embodiments of the invention are not intended to be limited to the precise structures and operations illustrated and described, but rather to encompass all suitable modifications and equivalents falling within their scope.

[0127] The parts of this invention not described in detail are techniques known to those skilled in the art.

Claims

1. A method for comprehensive temperature compensation of an inertial measurement unit, characterized in that, The temperature comprehensive compensation method includes The operating temperature range of the inertial measurement unit is divided into a series of temperature intervals, and a series of temperature points (T1, T2…T) are generated using the endpoints of these intervals. n ); The comprehensive compensation parameters of the three-axis gyroscope are calibrated based on the aforementioned series of temperature points, including: 1) Place the inertial measurement unit in a temperature chamber with a dual-axis turntable. Set the temperature chamber input to a series of temperature points (T1, T2…T…). n-1 ,T n ,T n-1 …T2,T1), the turntable input is set to a series of angular velocity points (±ω1,±ω2…±ω). n ); 2) The three gyroscope sensing axes are calibrated along the rotation axis of the turntable as follows: Make the temperature chamber operate according to the set input temperature points (T1, T2…T…). n-1 ,T n ,T n-1 …T2,T1) operation, for each temperature point: after holding at each temperature point for a preset time, the turntable is made to run at the set angular velocity point (±ω1,±ω2…±ω). n The system rotates, and during the rotation, the output data of the three-axis gyroscope of the inertial measurement unit is collected and recorded; the data collected at the same temperature point are averaged. 3) Temperature compensation is performed based on the designed three-axis gyroscope integrated compensation model and the data obtained in step 2); The comprehensive compensation parameter calibration of the triaxial accelerometer is performed based on the aforementioned series of temperature points, including: 11) Place the inertial measurement unit in an incubator equipped with a centrifuge. Set the incubator input to a series of temperature points (T1, T2…T…). n-1 ,T n ,T n-1 …T2,T1), the centrifuge input is set to a series of acceleration points (a1,a2…a…). n ); 12) The three accelerometer sensing axes were calibrated sequentially along the centrifugal axis and in the opposite direction as follows: Make the temperature chamber operate according to the set input temperature points (T1, T2…T…). n-1 ,T n ,T n-1 …T2,T1) operation, for each temperature point: after holding at each temperature point for a preset time, the centrifuge is made to accelerate to the set acceleration point (a1,a2…a…). n The system rotates, and during this rotation, the output data of the triaxial accelerometer of the inertial measurement unit is collected and recorded. The acceleration data in the reverse direction is calculated according to -a1, -a2…-a… n To record; average the data collected at the same temperature points; 13) Temperature compensation is performed based on the designed triaxial accelerometer integrated compensation model and the data obtained in step 12).

2. The method for comprehensive temperature compensation of an inertial measurement unit according to claim 1, characterized in that, Step 3) specifically includes: Based on the designed three-axis gyroscope comprehensive compensation model, the collected data is used to generate compensation parameters for the corresponding insulation temperature point. Repeat step 2) of data acquisition and compensation parameter generation at all temperature points until the last temperature point is set. After obtaining the comprehensive compensation parameters for all temperature points, the relationship between the comprehensive compensation parameters of the three-axis gyroscope and temperature is fitted. The compensation parameters are then substituted into the comprehensive compensation model of the three-axis gyroscope to finally obtain the angular velocity output equation of the inertial measurement unit.

3. The method for comprehensive temperature compensation of an inertial measurement unit according to claim 2, characterized in that, The designed three-axis gyroscope comprehensive compensation model is shown in the following formula: In the formula: ω x ,ω y ,ω z These are the true angular velocities of the inertial measurement unit along the x, y, and z axes, respectively. ω sx ,ω sy ,ω sz These are the output values ​​of the three-axis gyroscope of the inertial measurement unit along the x, y, and z axes, respectively. T represents the real-time temperature inside the inertial measurement unit; k mij (T) is the coupling coefficient between the j-axis output value and the m-th term of the true angular velocity of the i-axis of the three-axis gyroscope of the inertial measurement unit, and is a parameter that varies with temperature T. u 0x (T),u 0y (T),u 0z (T) represents the equivalent zero bias of the x, y, and z axes of the three-axis gyroscope in the inertial measurement unit, and is a parameter that varies with temperature T.

4. The method for comprehensive temperature compensation of an inertial measurement unit according to claim 3, characterized in that, In step 3), the comprehensive compensation parameters for all temperature points are obtained in the following manner: a. At a certain temperature, when the inertial measurement unit's x-axis is calibrated, the true angular velocity of the x-axis is the turntable's set angular velocity value, while the true angular velocities of the other two axes remain 0. Therefore, the following relationship is obtained: The relation is considered as having the independent variable as... ω sx ,ω sy ,ω sz 1, with ω as the dependent variable. x The functional relationship was determined, and a dataset was collected using a series of angular velocity points at this temperature. Using linear regression, the parameter k at the current temperature is obtained by fitting the data. 3xx ,k 3xy ,k 3xz ,k 2xx ,k 2xy ,k 2xz ,k 1xx ,k 1xy ,k 1xz ,u 0x ; b. Using the same method as in step a, other parameters in the model at the same temperature can be obtained, as shown below: k 3yx ,k 3yy ,k 3yz ,k 2yx ,k 2yy ,k 2yz ,k 1yx ,k 1yy ,k 1yz ,u 0y k 3zx ,k 3zy ,k 3zz ,k 2zx ,k 2zy ,k 2zz ,k 1zx ,k 1zy ,k 1zz ,u 0z c. Change the temperature to a series of temperature points n = T1, T2…T n-1 ,T n ,T n-1 …T2,T1, and the comprehensive compensation parameters for the corresponding temperature points can be obtained, as shown below: k 3xx (n),k 3xy (n),k 3xz (n),k 2xx (n),k 2xy (n),k 2xz (n),k 1xx (n),k 1xy (n),k 1xz (n),u 0x (n) k 3yx (n),k 3yy (n),k 3yz (n),k 2yx (n),k 2yy (n),k 2yz (n),k 1yx (n),k 1yy (n),k 1yz (n),u 0y (n) k 3zx (n),k 3zy (n),k 3zz (n),k 2zx (n),k 2zy (n),k 2zz (n),k 1zx (n),k 1zy (n),k 1zz (n),u 0z (n)。 5. The method for comprehensive temperature compensation of an inertial measurement unit according to claim 4, characterized in that, In step 3), each parameter sequence k mij (n),u 0x (n),u 0y (n),u 0z (n) respectively fits a polynomial relationship with the sequence n, thus obtaining the functional relationship between the comprehensive compensation parameters in the model and temperature: k 3xx (T),k 3xy (T),k 3xz (T),k 2xx (T),k 2xy (T),k 2xz (T),k 1xx (T),k 1xy (T),k 1xz (T),u 0x (T) k 3yx (T),k 3yy (T),k 3yz (T),k 2yx (T),k 2yy (T),k 2yz (T),k 1yx (T),k 1yy (T),k 1yz (T),u 0y (T) k 3zx (T),k 3zy (T),k 3zz (T),k 2zx (T),k 2zy (T),k 2zz (T),k 1zx (T),k 1zy (T),k 1zz (T),u 0z (T) Substituting the comprehensive compensation parameters into the three-axis gyroscope comprehensive compensation model yields the angular velocity output equation of the inertial measurement unit.

6. A method for comprehensive temperature compensation of an inertial measurement unit according to claims 1-5, characterized in that, Step 13) specifically includes: Based on the designed triaxial accelerometer integrated compensation model, the collected data is used to generate compensation parameters for the corresponding insulation temperature points. Repeat step 12) for data acquisition and compensation parameter generation at all temperature points until the last temperature point is set. After obtaining the comprehensive compensation parameters for all temperature points, the relationship between the comprehensive compensation parameters of the triaxial accelerometer and temperature is fitted. The compensation parameters are then substituted into the comprehensive compensation model of the triaxial accelerometer to finally obtain the acceleration output equation of the inertial measurement unit.

7. The method for comprehensive temperature compensation of an inertial measurement unit according to claim 6, characterized in that, In step 13), the designed triaxial accelerometer integrated compensation model is shown in the following equation: In the formula: a x ,a y ,a z These are the actual accelerations of the inertial measurement unit along the x, y, and z axes, respectively. a sx ,a sy ,a sz These are the output values ​​of the three-axis accelerometer of the inertial measurement unit along the x, y, and z axes, respectively. T represents the real-time temperature inside the inertial measurement unit; l mij (T) is the coupling coefficient between the j-axis output value of the triaxial accelerometer of the measurement unit and the m-th term of the actual acceleration of the i-axis, and is a parameter that varies with temperature T. m 0x (T),m 0y (T),m 0z (T) represents the equivalent zero bias of the x, y, and z axes of the triaxial accelerometer in the inertial measurement unit, and is a parameter that varies with temperature T.

8. The method for comprehensive temperature compensation of an inertial measurement unit according to claim 7, characterized in that, In step 13), the same calculation method as for the comprehensive compensation parameters of the triaxial gyroscope is used to obtain the functional relationship between the comprehensive compensation parameters and temperature in the triaxial accelerometer model: l 3xx (T),l 3xy (T),l 3xz (T),l 2xx (T),l 2xy (T),l 2xz (T),l 1xx (T),l 1xy (T),l 1xz (T),m 0x (T) l 3yx (T),l 3yy (T),l 3yz (T),l 2yx (T),l 2yy (T),l 2yz (T),l 1yx (T),l 1yy (T),l 1yz (T),m 0y (T) l 3zx (T),l 3zy (T),l 3zz (T),l 2zx (T),l 2zy (T),l 2zz (T),l 1zx (T),l 1zy (T),l 1zz (T),m 0z (T) Substituting the obtained comprehensive compensation parameters into the triaxial accelerometer comprehensive compensation model yields the acceleration output equation of the inertial measurement unit.

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