CN112082544B

CN112082544B - IMU data compensation method and device

Info

Publication number: CN112082544B
Application number: CN201910507528.0A
Authority: CN
Inventors: 陈燃
Original assignee: Hangzhou Haikang Automobile Technology Co ltd
Current assignee: Hangzhou Haikang Automobile Technology Co ltd
Priority date: 2019-06-12
Filing date: 2019-06-12
Publication date: 2022-09-30
Anticipated expiration: 2039-06-12
Also published as: CN112082544A

Abstract

The invention provides an IMU data compensation method and a device, wherein the method comprises the following steps: acquiring first IMU data acquired when the moving speed of the IMU is smaller than a speed threshold; calculating a first conversion relation according to the first IMU data and the standard IMU data, wherein the installation posture of the IMU corresponds to a first coordinate system, the first conversion relation is a conversion relation between the first coordinate system and a second coordinate system, and the second coordinate system is a coordinate system calibrated based on the gravity direction of the IMU; acquiring second IMU data acquired when the IMU moves linearly, and converting the second IMU data into third IMU data according to a first conversion relation; calculating a second conversion relation according to the third IMU data, wherein the second conversion relation is a conversion relation between a second coordinate system and a third coordinate system, and the third coordinate system is a coordinate system calibrated based on the advancing direction of the IMU during linear movement; and compensating the IMU data acquired by the IMU by using the first conversion relation and the second conversion relation. The compensated IMU data has higher accuracy, and the requirement on the installation posture of the inertial sensor can be reduced.

Description

IMU data compensation method and device

Technical Field

The invention relates to the technical field of measurement, in particular to an IMU data compensation method and device.

Background

An Inertial sensor (IMU) is a device for measuring the three-axis attitude angle and acceleration of an object. The inertial sensor is usually mounted on a movable platform, such as a vehicle, an unmanned aerial vehicle, etc., and its measurement data can be used as a basis for detecting the driving state of the movable platform.

In the case of a vehicle, it is often necessary to determine rapid acceleration/deceleration and sharp cornering in detecting a running state of the vehicle, and it is difficult for an external device to directly obtain data on the engine or braking operation of the vehicle and the wheel deflection, and this determination depends on measurement data of an inertial sensor. For example, if the vehicle peripheral can obtain the acceleration of the vehicle in the traveling direction by the inertial sensor, it is possible to relatively easily observe the occurrence of a peak in the acceleration data to determine rapid acceleration and deceleration.

In order to meet the requirements, the conventional method is to ensure the accuracy of the measurement data of the inertial sensor by ensuring the more accurate installation attitude of the inertial sensor, and has the problems that the requirement on the installation attitude of the inertial sensor is higher: taking the vehicle as an example, when the inertial sensor is mounted on the vehicle, it is necessary to ensure that one axis of the coordinate system corresponding to the mounting posture of the inertial sensor is in the same direction as the advancing direction of the vehicle to measure the data required for accurately judging the rapid acceleration and deceleration, and meanwhile, the inertial sensor is prevented from inclining to reduce the influence of the component of the gravitational acceleration on the judgment.

Disclosure of Invention

In view of this, the invention provides an IMU data compensation method and apparatus, and the compensated IMU data is higher in accuracy, and can reduce the requirement for the installation attitude of the inertial sensor.

The invention provides an IMU data compensation method in a first aspect, which comprises the following steps:

acquiring first inertial sensor IMU data acquired when the moving speed of the inertial sensor IMU is smaller than a speed threshold;

calculating a first conversion relation according to the first IMU data and preset standard IMU data, wherein the installation posture of the IMU corresponds to a first coordinate system, the first conversion relation is a conversion relation between the first coordinate system and a second coordinate system, and the second coordinate system is a coordinate system calibrated based on the gravity direction of the IMU;

acquiring second IMU data acquired when the IMU moves linearly, and converting the second IMU data into third IMU data according to the first conversion relation;

calculating a second conversion relation according to the third IMU data, wherein the second conversion relation is a conversion relation between a second coordinate system and a third coordinate system, and the third coordinate system is a coordinate system calibrated based on the advancing direction of the IMU during linear movement;

and compensating the IMU data acquired by the IMU by using the first conversion relation and the second conversion relation.

According to an embodiment of the present invention, calculating a first transformation relation according to the first IMU data and preset standard IMU data includes:

determining first reference data required for calculating a first conversion relation according to the acquired first IMU data;

calculating a conversion relation from the first reference data to the standard IMU data;

determining the conversion relationship as the first conversion relationship.

In accordance with one embodiment of the present invention,

the first IMU data comprises initial acceleration data of the IMU along three different coordinate axes of a first coordinate system;

determining first reference data required for calculating a first transformation relationship from the acquired first IMU data, comprising:

checking whether there is currently first historical accumulated data required to determine the first reference data;

if not, storing initial acceleration data of the IMU along three different coordinate axes of a first coordinate system in the currently acquired first IMU data as first historical accumulated data, and returning to the operation of acquiring the IMU data of the first inertial sensor acquired when the moving speed of the IMU is smaller than a speed threshold;

if so, calculating the accumulated values of the IMU along three different coordinate axes of the first coordinate system, and updating the accumulated times, wherein the accumulated values of the IMU along the three different coordinate axes of the first coordinate system are obtained by respectively adding the initial acceleration data of the IMU along the three different coordinate axes of the first coordinate system in the currently acquired first IMU data and the data along the three different coordinate axes of the first coordinate system in the first historical accumulated data;

if the updated accumulation times do not reach a first accumulation threshold value, taking the accumulated values of the IMU along three different coordinate axes of a first coordinate system as first historical accumulation data, and returning to the operation of acquiring the first inertial sensor IMU data acquired when the moving speed of the inertial sensor IMU is smaller than the speed threshold value; and if the updated accumulation times reach a first accumulation threshold value, determining the ratio of the accumulation values of the IMU along three different coordinate axes of the first coordinate system to the first accumulation threshold value as the first reference data.

According to an embodiment of the invention, calculating a second transformation relation from the third IMU data includes:

determining second reference data required for calculating a second conversion relation according to the third IMU data;

and calculating a second conversion relation according to the second reference data.

In accordance with one embodiment of the present invention,

the third IMU data includes: candidate acceleration data of the IMU along three different coordinate axes of a second coordinate system;

determining second reference data required for calculating a second transformation relationship from the third IMU data, including:

checking whether there is currently second historically accumulated data needed to determine the second reference data;

if not, storing the candidate acceleration data of the IMU along the X axis and the Y axis of a second coordinate system as second historical accumulated data, and returning to the operation of acquiring second IMU data acquired when the IMU moves linearly;

if so, calculating the accumulated values of the IMU along the X axis and the Y axis of the second coordinate system, and updating the accumulated times, wherein the accumulated values of the IMU along the X axis and the Y axis of the second coordinate system are obtained by respectively adding the candidate acceleration data of the IMU along the X axis and the Y axis of the second coordinate system and the data along the X axis and the Y axis of the second coordinate system in the second historical accumulated data;

if the updated accumulation times do not reach a second accumulation threshold value, taking the accumulated values of the IMU along the X axis and the Y axis of a second coordinate system as second historical accumulation data, and returning to the operation of acquiring the second IMU data acquired when the IMU moves linearly; and if the updated accumulation times reach a second accumulation threshold value, determining the accumulated value of the IMU along the X axis and the Y axis of a second coordinate system as the second reference data.

According to an embodiment of the invention, calculating a second transformation relation from the second reference data comprises:

determining the advancing direction of the IMU according to the accumulated value of the IMU along the X axis and the Y axis of a second coordinate system;

calculating an included angle between the advancing direction of the IMU and a target coordinate axis, wherein the target coordinate axis is a coordinate axis in the second coordinate system, and the direction of the target coordinate axis is closest to the advancing direction of the IMU;

calculating the function relation of the candidate acceleration data of the IMU projected to the advancing direction along the X axis and the Y axis of a second coordinate system respectively according to the included angle;

and determining the functional relation as the second conversion relation.

According to one embodiment of the present invention, determining the advancing direction of the IMU according to the accumulated value of the IMU along the X-axis and the Y-axis of the second coordinate system comprises:

determining a target coordinate position in the second coordinate system corresponding to an accumulated value of the IMU along X and Y axes of the second coordinate system;

and determining the direction from the origin coordinate position to the target coordinate position in the second coordinate system as the advancing direction.

According to one embodiment of the invention, acquiring second IMU data acquired by the IMU while moving linearly comprises:

obtaining current IMU data acquired by the IMU, wherein the current IMU data comprises: acceleration data of the IMU along three different coordinate axes of a first coordinate system and first angular velocity data of the IMU along a Z axis of the first coordinate system;

converting the first angular velocity data into second angular velocity data according to the first conversion relation;

and checking whether the second angular velocity data is smaller than a set angular velocity value, and if so, determining acceleration data of the IMU in the current IMU data along three different coordinate axes of a first coordinate system as second IMU data.

A second aspect of the present invention provides an IMU data compensation apparatus, including:

the first data acquisition module is used for acquiring first inertial sensor IMU data acquired when the moving speed of the inertial sensor IMU is smaller than a speed threshold value;

the first calculation module is used for calculating a first conversion relation according to the first IMU data and preset standard IMU data, wherein the installation posture of the IMU corresponds to a first coordinate system, the first conversion relation is a conversion relation between the first coordinate system and a second coordinate system, and the second coordinate system is a coordinate system calibrated based on the gravity direction of the IMU;

the second data acquisition module is used for acquiring second IMU data acquired when the IMU moves linearly and converting the second IMU data into third IMU data according to the first conversion relation;

a second calculation module, configured to calculate a second transformation relationship according to the third IMU data, where the second transformation relationship is a transformation relationship between the second coordinate system and a third coordinate system, and the third coordinate system is a coordinate system calibrated based on a forward direction of the IMU during linear movement;

and the data compensation module is used for compensating the IMU data acquired by the IMU by utilizing the first conversion relation and the second conversion relation.

According to one embodiment of the invention, the first calculation module comprises:

the first reference data determining unit is used for determining first reference data required for calculating the first conversion relation according to the acquired first IMU data;

the conversion relation calculation unit is used for calculating the conversion relation from the first reference data to the standard IMU data;

a first conversion relation determination unit configured to determine the conversion relation as the first conversion relation.

In accordance with one embodiment of the present invention,

when the first reference data determining unit determines, according to the acquired first IMU data, first reference data required for calculating the first conversion relationship, the first reference data determining unit is specifically configured to:

checking whether there is currently first historically accumulated data needed to determine the first reference data;

According to one embodiment of the invention, the second calculation module comprises:

a second reference data determining unit, configured to determine, according to the third IMU data, second reference data required to calculate the second transform relationship;

and the second conversion relation calculation unit is used for calculating a second conversion relation according to the second reference data.

In accordance with one embodiment of the present invention,

when the second reference data determining unit determines, according to the third IMU data, second reference data required for calculating the second conversion relationship, the second reference data determining unit is specifically configured to:

if the updated accumulation times do not reach a second accumulation threshold value, taking the accumulated values of the IMU along the X axis and the Y axis of a second coordinate system as second historical accumulation data, and returning to the operation of acquiring the second IMU data acquired when the IMU moves linearly; and if the updated accumulation times reach a second accumulation threshold value, determining the accumulated value of the IMU along the X axis and the Y axis of the second coordinate system as the second reference data.

According to an embodiment of the present invention, when the second conversion relation calculating unit calculates the second conversion relation according to the second reference data, the second conversion relation calculating unit is specifically configured to:

calculating an included angle between the advancing direction of the IMU and a target coordinate axis, wherein the target coordinate axis is a coordinate axis in the second coordinate system, and the direction of the coordinate axis is closest to the advancing direction of the IMU;

and determining the functional relation as the second conversion relation.

According to an embodiment of the present invention, when the second transformation relation calculating unit determines the advancing direction of the IMU according to the accumulated value of the IMU along the X axis and the Y axis of the second coordinate system, the second transformation relation calculating unit is specifically configured to:

determining a target coordinate position in the second coordinate system corresponding to an accumulated value of the IMU along an X-axis and a Y-axis of the second coordinate system;

According to an embodiment of the invention, the second data acquisition module comprises:

a data obtaining unit, configured to obtain current IMU data acquired by the IMU, where the current IMU data includes: acceleration data of the IMU along three different coordinate axes of a first coordinate system and first angular velocity data of the IMU along a Z axis of the first coordinate system;

an angular velocity data conversion unit for converting the first angular velocity data into second angular velocity data in accordance with the first conversion relationship;

and the data determining unit is used for checking whether the second angular velocity data is smaller than a set angular velocity value or not, and if so, determining the acceleration data of the IMU in the current IMU data along three different coordinate axes of the first coordinate system as the second IMU data.

A third aspect of the invention provides an electronic device comprising a processor and a memory; the memory stores a program that can be called by the processor; wherein, when the processor executes the program, the IMU data compensation method as described in the foregoing embodiments is implemented.

A fourth aspect of the present invention provides a machine-readable storage medium on which a program is stored, the program, when executed by a processor, implementing the IMU data compensation method as described in the foregoing embodiments.

The embodiment of the invention has the following beneficial effects:

in the embodiment of the invention, the first IMU data acquired when the IMU moves at a speed lower than the speed threshold can represent the installation posture of the IMU, so that a first conversion relation can be calculated according to the first IMU data and standard IMU data, the first conversion relation is the conversion relation between a first coordinate system corresponding to the installation posture and a second coordinate system calibrated based on the gravity direction of the IMU, the second IMU data acquired when the IMU moves linearly is converted into third IMU data according to the first conversion relation, the data deviation caused by the deviation of the installation posture of the IMU in the vertical direction can be compensated, the third IMU data can represent the horizontal direction of the IMU, so that a second conversion relation can be calculated according to the third IMU data, the second conversion relation is the conversion relation between the second coordinate system and a third coordinate system calibrated based on the advancing direction of the IMU when the IMU moves linearly, the IMU data acquired by the IMU is compensated according to the first conversion relation and the second conversion relation, the problem of inaccurate data caused by deviation of the installation posture of the IMU in the horizontal direction and the vertical direction can be solved, the compensated IMU data is high in accuracy, and the requirement on the installation posture of the inertial sensor can be lowered.

Drawings

FIG. 1 is a flow chart illustrating an IMU data compensation method according to an embodiment of the present invention;

FIG. 2 is a block diagram of an IMU data compensation apparatus according to an embodiment of the present invention;

FIG. 3 is a flowchart illustrating a process of calculating a first transformation relation according to an embodiment of the invention;

FIG. 4 is a flowchart illustrating a process of determining first reference data according to an embodiment of the present invention;

FIG. 5 is a flowchart illustrating a process of calculating a second transformation relation according to an embodiment of the invention;

FIG. 6 is a flowchart illustrating a process of determining second reference data according to an embodiment of the present invention;

FIG. 7 is a flowchart illustrating a process of calculating a second transformation relation according to second reference data according to an embodiment of the invention;

FIG. 8 is a schematic view of determining a forward direction according to an embodiment of the present invention;

FIG. 9 is a flowchart illustrating a process of obtaining second IMU data according to one embodiment of the present invention;

fig. 10 is a block diagram of an electronic device according to an embodiment of the present invention.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the invention, as detailed in the appended claims.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one type of device from another. For example, a first device may also be referred to as a second device, and similarly, a second device may also be referred to as a first device, without departing from the scope of the present invention. The word "if" as used herein may be interpreted as "at … …" or "when … …" or "in response to a determination", depending on the context.

The IMU data compensation method in the embodiment of the invention can be applied to mobile scenes, such as movable platforms of unmanned planes, vehicles and the like. In the case of a vehicle, an inertial sensor is mounted on the vehicle to measure acceleration, angular velocity, and the like of the vehicle during running, and thereby determine a running state of the vehicle, such as whether rapid acceleration/deceleration, sharp turning, and the like are generated.

However, the installation posture of the inertial sensor on the vehicle is not satisfactory, which may be caused by installation inaccuracy or may be caused by a change in the installation posture during the running of the vehicle. The requirement that one axis of a coordinate system corresponding to the inclination and/or installation posture of the inertial sensor is different from the advancing direction of the vehicle is not met. In this case, if the driving state of the vehicle is determined directly using the data collected by the inertial sensor, the result may be biased.

The embodiment of the invention can solve the problem, under the condition that the installation attitude of the inertial sensor does not meet the requirement, the installation attitude of the inertial sensor does not need to be changed, but the conversion relation needed for compensating the data deviation caused by the fact that the installation attitude does not meet the requirement is determined, the IMU data acquired by the inertial sensor is compensated by utilizing the conversion relation, the accuracy of the compensated IMU data is higher, and the requirement on the installation attitude of the inertial sensor can be reduced.

The following describes the IMU data compensation method according to the embodiment of the present invention in detail, but the invention should not be limited thereto. Referring to FIG. 1, in one embodiment, an IMU data compensation method includes the steps of:

s100: acquiring first inertial sensor IMU data acquired when the moving speed of the inertial sensor IMU is smaller than a speed threshold;

s200: calculating a first conversion relation according to the first IMU data and preset standard IMU data, wherein the installation posture of the IMU corresponds to a first coordinate system, the first conversion relation is a conversion relation between the first coordinate system and a second coordinate system, and the second coordinate system is a coordinate system calibrated based on the gravity direction of the IMU;

s300: acquiring second IMU data acquired when the IMU moves linearly, and converting the second IMU data into third IMU data according to the first conversion relation;

s400: calculating a second conversion relation according to the third IMU data, wherein the second conversion relation is a conversion relation between a second coordinate system and a third coordinate system, and the third coordinate system is a coordinate system calibrated based on the advancing direction of the IMU during linear movement;

s500: and compensating the IMU data acquired by the IMU by using the first conversion relation and the second conversion relation.

In the embodiment of the present invention, an execution subject of the IMU data compensation method may be an electronic device, such as a computer device, an embedded device, and the like. The electronic device may be mounted on a movable platform. An inertial sensor IMU may also be mounted on the movable platform. The IMU can be used for collecting data such as acceleration, angular velocity and the like of the movable platform in the driving process, can be electrically connected with the electronic equipment, and transmits the collected data to the electronic equipment. The movable platform may be a vehicle, a drone, or the like.

When the IMU installation posture meets the requirements (the IMU is not inclined and the horizontal orientation is accurate), in the first coordinate system corresponding to the IMU installation posture, the Z-axis direction and the gravity direction of the IMU should be the same direction, and the direction of the designated coordinate axis (X-axis or Y-axis) and the advancing direction of the IMU should be the same direction.

However, in practice, it cannot be guaranteed that the installation posture of the IMU meets the requirements when the IMU is installed, and the installation posture of the IMU also changes in the use process, so that the Z-axis direction of the first coordinate system may deflect relative to the gravity direction of the IMU, and the designated coordinate axis may deflect relative to the advancing direction of the vehicle, and thus, the IMU data acquired by the IMU is inaccurate, which is compensated by the embodiment of the present invention.

In step S100, first inertial sensor IMU data acquired when the moving speed of the inertial sensor IMU is less than a speed threshold is acquired.

The first IMU data at least comprises first initial acceleration data, second initial acceleration data and third initial acceleration data, wherein the first initial acceleration data, the second initial acceleration data and the third initial acceleration data are acceleration data of the IMU along three different coordinate axes of a first coordinate system, the three different coordinate axes are an X axis, a Y axis and a Z axis of the first coordinate system, and the first coordinate system is a coordinate system corresponding to the IMU installation posture.

Acquiring first IMU data acquired by the IMU when the movement speed is less than the speed threshold may include: acquiring current IMU data acquired by the IMU, checking whether the moving speed of the IMU during the acquisition of the current IMU data is smaller than a speed threshold value, if so, determining the current IMU data as first IMU data, and if not, determining that the current IMU data is not the first IMU data.

When the IMU is mounted on the movable platform, the moving speed of the movable platform is the same as the moving speed of the IMU, and thus the moving speed of the movable platform can be regarded as the moving speed of the IMU. Taking the movable platform as an example, checking whether the moving speed of the IMU when acquiring the current IMU data is less than the speed threshold may include: the method comprises the steps of obtaining the current vehicle speed when the current IMU data are collected, judging whether the current vehicle speed is smaller than a speed threshold value, and if so, determining that the moving speed of the IMU when the current IMU data are collected is smaller than the speed threshold value.

The speed threshold may be a value slightly larger than 0, for example, a value less than or equal to 1KM/H, although the specific value is not limited as long as it is ensured that the vehicle is in a stationary stable state when the moving speed is less than the speed threshold. In a static stable state, the IMU is only influenced by gravity, so that the acquired IMU data only comprises acceleration data in the gravity direction. In other words, the first IMU data is IMU data acquired by the IMU in a static steady state.

In step S200, a first transformation relation is calculated according to the first IMU data and preset standard IMU data, the installation posture of the IMU corresponds to a first coordinate system, the first transformation relation is a transformation relation between the first coordinate system and a second coordinate system, and the second coordinate system is a coordinate system calibrated based on a gravity direction of the IMU.

The standard IMU data comprises acceleration data of the IMU along three different coordinate axes of a second coordinate system, wherein the acceleration data along the Z axis of the second coordinate system is G, the acceleration data along the X axis and the Y axis of the second coordinate system is 0, namely the standard IMU data is (0,0, G), and G is gravity acceleration.

The second coordinate system is a coordinate system calibrated based on the gravity direction of the IMU, the Z-axis direction of the second coordinate system is the same as the gravity direction of the IMU, the second coordinate system is a corresponding coordinate system when the IMU is installed in an ideal horizontal posture, and namely the Z-axis direction of the second coordinate system is the vertical direction.

If the installation posture of the IMU is not inclined, the Z axes of the first coordinate system and the second coordinate system are in the same direction, the acquired first IMU data is supposed to be consistent with the preset standard acceleration data, otherwise, the acquired IMU data is supposed to be inconsistent with the preset standard acceleration data.

Specifically, if the IMU is not tilted and the gravity direction of the IMU and the Z-axis direction of the first coordinate system are in the same direction, then in the first IMU data collected, it is supposed that the initial acceleration data along the Z-axis of the first coordinate system is G, and the initial acceleration data along the X-axis and the Y-axis of the first coordinate system is 0, that is, the first IMU data is supposed to be (0,0, G). However, if the IMU is tilted such that the gravity direction of the IMU no longer coincides with the Z-axis direction of the first coordinate system and the gravitational acceleration is dispersed in all axes, then the first IMU data is no longer (0,0, G) and the initial acceleration data of the IMU along the X-axis and Y-axis of the first coordinate system is no longer 0.

The standard IMU data embodies the ideal horizontal attitude of the IMU; and the first IMU data is IMU data acquired when the movement speed of the IMU is smaller than a speed threshold value, and the current installation posture of the IMU is embodied. The first conversion relationship can be obtained by calculating in reverse how the conversion of the IMU that should be placed horizontally would produce the deviation between the current Z-axis and the direction of gravity based on the standard IMU data and the first IMU data.

In other words, the first conversion relationship may be calculated from the first IMU data and preset standard IMU data. The first transformation relation is a transformation relation between a first coordinate system and a second coordinate system, and the data on three axes in the first coordinate system can be rotationally transformed to the data on three axes in the second coordinate system. Using the first translation relationship, subsequent IMU data may be translated back to data when the direction of gravity is co-directional with the Z-axis.

In step S300, second IMU data acquired when the IMU moves linearly is acquired, and the second IMU data is converted into third IMU data according to the first conversion relationship.

The second IMU data is IMU data acquired while the IMU is moving in a straight line. Because the IMU may have a large acceleration in a direction perpendicular to the direction of travel when turning, which may significantly affect the determination of the direction of travel, the record may be discarded and the second IMU data retrieved when a turn is detected.

And the second IMU data is converted through the first conversion relation to obtain third IMU data, so that the acceleration in the horizontal direction only reflects the acceleration data of the third IMU data along the X axis and the Y axis of the second coordinate system, and no component exists on the Z axis, the acceleration of the IMU in the vertical direction is corrected, and the acceleration data of the IMU in the third IMU data along the Z axis of the second coordinate system is the corrected acceleration data of the IMU in the vertical direction.

Based on the above conversion, only the accuracy of the acceleration data in the vertical direction is ensured, and the accuracy of the acceleration data in the forward direction is not ensured, so that step S400 is further performed.

In step S400, a second transformation relationship is calculated according to the third IMU data, where the second transformation relationship is a transformation relationship between the second coordinate system and a third coordinate system, and the third coordinate system is a coordinate system calibrated based on a forward direction of the IMU during the linear movement.

The second conversion relationship is a conversion relationship between the second coordinate system and the third coordinate system, and the data on three axes in the second coordinate system can be rotationally converted to the data on three axes in the third coordinate system. The third coordinate system is a coordinate system calibrated based on the advancing direction of the IMU during linear movement, the third coordinate system is a coordinate system corresponding to the IMU when the mounting posture of the IMU is assumed to be the direction of a specified coordinate axis (an X axis or a Y axis) and the advancing direction, and the direction of the specified coordinate axis of the third coordinate system is the same as the advancing direction of the IMU.

Since the acceleration in the horizontal direction is only included in the acceleration data of the third IMU data along the X-axis and the Y-axis of the second coordinate system, there is no component in the Z-axis. Therefore, the third IMU data can reflect the advancing direction of the IMU, and the second conversion relationship can be obtained by reversely calculating how to convert the IMU, which should be horizontally placed and has the advancing direction in the same direction as the direction of the designated coordinate axis, into the current installation attitude according to the third IMU data.

In step S500, the IMU data collected by the IMU is compensated using the first and second transformation relationships.

After the first conversion relation and the second conversion relation are determined, when the IMU data acquired by the IMU is acquired, the IMU data is converted according to the first conversion relation, for example, acceleration data of the IMU along three different coordinate axes of the first coordinate system is converted into acceleration data of the IMU along three different coordinate axes of the second coordinate system, and then the IMU data converted through the first conversion relation is converted according to the second conversion relation, for example, the acceleration data of the IMU along three different coordinate axes of the second coordinate system is converted into acceleration data of the IMU along three different coordinate axes of the third coordinate system.

Based on the conversion of the two conversion relations, the data deviation caused by the installation attitude deviation of the IMU in the vertical direction and the advancing direction can be compensated, the compensated IMU data is high in accuracy, and the requirement on the installation attitude of the inertial sensor can be reduced.

In the embodiment of the invention, the first IMU data acquired when the IMU moves at a speed less than a speed threshold can represent the installation attitude of the IMU, so that a first conversion relation can be calculated according to the first IMU data and standard IMU data, the first conversion relation is a conversion relation between a first coordinate system corresponding to the installation attitude and a second coordinate system calibrated based on the gravity direction of the IMU, the second IMU data acquired when the IMU moves linearly is converted into third IMU data according to the first conversion relation, data deviation caused by deviation of the installation attitude of the IMU in the vertical direction can be compensated, the third IMU data can represent the horizontal direction of the IMU, so that a second conversion relation can be calculated according to the third IMU data, the second conversion relation is a conversion relation between the second coordinate system and a third coordinate system calibrated based on the advancing direction of the IMU when the IMU moves linearly, the IMU data acquired by the IMU is compensated according to the first conversion relation and the second conversion relation, the problem of inaccurate data caused by deviation of the installation posture of the IMU in the horizontal direction and the vertical direction can be solved, the compensated IMU data is high in accuracy, and the requirement on the installation posture of the inertial sensor can be lowered.

In addition, the embodiment of the invention also solves the problem of IMU installation, can install the IMU in any posture, does not influence the detection performance of the form state completely, saves a series of complex calibration work carried out when the IMU is installed, and saves the precious time of a user to a greater extent.

In one embodiment, the above method flow can be executed by the IMU data compensation apparatus 100, as shown in fig. 2, the IMU data compensation apparatus 100 mainly includes 5 modules: a first data acquisition module 101, a first calculation module 102, a second data acquisition module 103, a second calculation module 104 and a data compensation module 105. The first data obtaining module 101 is configured to perform the step S100, the first calculating module 102 is configured to perform the step S200, the second data obtaining module 103 is configured to perform the step S300, the second calculating module 104 is configured to perform the step S400, and the data compensating module 105 is configured to perform the step S500.

In one embodiment, the IMU is mounted on a movable platform, and after step S500, the driving state of the movable platform can be determined according to the compensated IMU data, so as to ensure the accuracy of the driving state result.

Taking the movable platform as an example, determining the driving state of the movable platform according to the compensated IMU data may include: calculating the instantaneous acceleration of the vehicle in the driving direction according to the acceleration data of the IMU in the compensated IMU data along a specified coordinate axis (a coordinate axis in the horizontal direction, which can be an X axis or a Y axis) in a third coordinate system, and judging whether the vehicle is subjected to rapid acceleration and deceleration according to the instantaneous acceleration and deceleration; and/or judging whether a sharp turn occurs or not according to the acceleration data of the IMU in the compensated IMU data along the Z axis in the third coordinate system; and/or, estimating the wheel rotation angle by the vehicle running speed, the turning angle speed and the wheel base according to the compensated IMU data, and the like, which is not limited thereto. When the abnormal state is determined, the alarm can be further given.

In actual operation, the VSD (vehicle driving stability detection module, which is mainly used for detecting whether there is behavior such as rapid acceleration, rapid deceleration, and rapid turning) of the vehicle can be called to determine the driving state of the movable platform according to the compensated IMU data.

The vehicle can obtain IMU data and vehicle state information such as vehicle speed and some callback functions by using an external calling interface. The IMU data may be continuously updated into the vehicle during operation, which may be on the order of 100 times per second.

Because the vehicle does not directly access the IMU for reading, but calls IMU data by using an external calling interface, when individual data is abnormal, the IMU data can be obtained again, which is equivalent to filtering the data, so that the individual data abnormality can not cause great influence on the process.

Referring to fig. 3, in one embodiment, in step S200, calculating a first transformation relation according to the first IMU data and the preset standard IMU data includes the following steps:

s201: determining first reference data required for calculating a first conversion relation according to the acquired first IMU data;

s202: calculating a conversion relation from the first reference data to the standard IMU data;

s203: determining the conversion relationship as the first conversion relationship.

The first reference data can be obtained by counting the acquired first IMU data, so that the problem of inaccurate calculation caused by individual data abnormity can be avoided. And calculating a conversion relation from the first reference data to standard IMU data as a first conversion relation.

The calculation process of the first conversion relation is described below in detail.

Assuming that the IMU is changed from an initial standard posture (posture corresponding to the second coordinate system) to a current installation posture (installation posture corresponding to the first coordinate system) after being rotated by α degrees around the X axis and β degrees around the Y axis of the second coordinate system, the rotation relationship is expressed by the first reference data and the standard IMU data:

the standard IMU data are:

after a rotation of a degrees around the X axis:

after rotating by β degrees around the Y axis:

namely the first reference data;

in the above relation, the order of the rotation around the axis and the angle values of α and β are both assumptions, and if the above relation is reversely reduced, a solution that may realize the reduction process is not unique, and an optimal solution may be selected. Here, due to computational requirements, the calculations are assumed to be uniformly performed in the order of first rotating by α degrees about the X axis and β degrees about the Y axis, and specifying-90 ° < α < 90 °, -180 ° < β < 180 °:

assuming first reference IMU data:

then, using the first reference data, the following values can be solved:

sinα＝-y/G

sinβ＝x/G/cosα

cosβ＝z/G/cosα。

using the set of values, a transformation relationship from the first reference IMU data to the predetermined IMU data is determined, which is the first transformation relationship.

The first conversion relationship is verified using the first IMU data, and the first IMU data is converted according to the first conversion relationship, as follows:

first IMU data:

after rotating- β around the Y axis:

after rotating- α around the Y axis we obtain:

the above results prove that the first IMU data can be converted into the standard IMU data according to the first conversion relationship, which realizes the overall conversion of data on three axes without changing the relative relationship between data on three axes.

When the first conversion relation is used, any IMU data acquired by the IMU in the current installation posture can be converted according to the first conversion relation, and the process is as follows:

the IMU data collected by the IMU under the current installation posture is as follows:

after rotating- β around the Y axis:

after rotating- α again around the X axis:

in one embodiment, the first IMU data includes initial acceleration data of the IMU along three different coordinate axes of a first coordinate system;

referring to fig. 4, in step S201, determining first reference data required for calculating the first conversion relationship according to the acquired first IMU data includes:

s2011: checking whether there is currently first historically accumulated data needed to determine the first reference data;

s2012: if not, storing initial acceleration data of the IMU along three different coordinate axes of a first coordinate system in the currently acquired first IMU data as first historical accumulated data, and returning to the operation of acquiring the IMU data of the first inertial sensor acquired when the moving speed of the IMU is smaller than a speed threshold;

s2013: if so, calculating the accumulated values of the IMU along three different coordinate axes of the first coordinate system, and updating the accumulated times, wherein the accumulated values of the IMU along the three different coordinate axes of the first coordinate system are obtained by respectively adding the initial acceleration data of the IMU along the three different coordinate axes of the first coordinate system in the currently acquired first IMU data and the data along the three different coordinate axes of the first coordinate system in the first historical accumulated data;

s2014: if the updated accumulation times do not reach a first accumulation threshold value, the accumulated values of the IMU along three different coordinate axes of a first coordinate system are used as first historical accumulation data, and the operation of acquiring the IMU data of the first inertial sensor acquired by the IMU when the moving speed of the IMU is smaller than the speed threshold value is returned; and if the updated accumulation times reach a first accumulation threshold value, determining the ratio of the accumulation values of the IMU along three different coordinate axes of the first coordinate system to the first accumulation threshold value as the first reference data.

In steps S2011-S2014, the obtained first IMU data are accumulated, the first historical accumulated data are data obtained by respectively accumulating initial acceleration data of the IMU along each coordinate axis of the first coordinate system in each first IMU data, and the first historical accumulated data include accumulated values of the IMU along three different coordinate axes of the first coordinate system.

In the whole accumulation process, when the accumulation times reach a first accumulation threshold value, the ratio of the accumulation values of the IMU along three different coordinate axes of the first coordinate system to the first accumulation threshold value is determined as the first reference data, otherwise, the first IMU data is continuously obtained for accumulation.

The value of the first accumulation threshold is not limited, and may be 128, for example, as long as the value is greater than 1. The first reference data is guaranteed to be statistical data of a certain amount of first IMU data, the first conversion relation is determined according to the statistical data, and the problem that the first conversion relation is inaccurate due to individual data abnormity can be avoided.

In the process of acquiring the first IMU data acquired by the IMU when the moving speed is smaller than the speed threshold, if the IMU data acquired by the IMU when the moving speed is greater than or equal to the speed threshold is acquired, the currently stored first historical accumulated data can be deleted, accumulation is performed again, the operation of acquiring the first IMU data acquired by the inertial sensor IMU when the moving speed is smaller than the speed threshold is returned, the first historical accumulated data is obtained by continuously maintaining the first IMU data acquired by the IMU when the moving speed is smaller than the speed threshold by the IMU, and the stability of the data is ensured.

The first reference data may include first reference acceleration data, second reference acceleration data, and third reference acceleration data, where the first reference acceleration data, the second reference acceleration data, and the third reference acceleration data are respectively mean values of initial acceleration data of three coordinate axes in the first IMU data acquired in the accumulation process.

Referring to FIG. 5, in one embodiment, the step S400 of calculating the second transformation relationship based on the third IMU data includes the steps of:

s401: determining second reference data required for calculating a second conversion relation according to the third IMU data;

s402: and calculating a second conversion relation according to the second reference data.

The second reference data can be obtained by counting the acquired first IMU data, the characteristics of the third IMU data are reserved, the current advancing direction of the IMU can be determined according to the first reference data, and the IMU which is originally placed horizontally and the advancing direction of which is the same as the direction of the specified coordinate axis is converted into the current installation attitude through reverse calculation, so that the second conversion relation can be obtained.

In one embodiment, the third IMU data includes: candidate acceleration data of the IMU along three different coordinate axes of a second coordinate system;

referring to fig. 6, in step S401, determining second reference data required for calculating a second conversion relationship according to the third IMU data includes:

s4011: checking whether there is currently second historically accumulated data needed to determine the second reference data;

s4012: if not, storing the candidate acceleration data of the IMU along the X axis and the Y axis of a second coordinate system as second historical accumulated data, and returning to the operation of acquiring second IMU data acquired when the IMU moves linearly;

s4013: if so, calculating the accumulated values of the IMU along the X axis and the Y axis of the second coordinate system, and updating the accumulated times, wherein the accumulated values of the IMU along the X axis and the Y axis of the second coordinate system are obtained by respectively adding the candidate acceleration data of the IMU along the X axis and the Y axis of the second coordinate system and the data along the X axis and the Y axis of the second coordinate system in the second historical accumulated data;

s4014: if the updated accumulation times do not reach a second accumulation threshold value, taking the accumulated values of the IMU along the X axis and the Y axis of a second coordinate system as second historical accumulation data, and returning to the operation of acquiring the second IMU data acquired when the IMU moves linearly; and if the updated accumulation times reach a second accumulation threshold value, determining the accumulated value of the IMU along the X axis and the Y axis of the second coordinate system as the second reference data.

And after the acquired second IMU data acquired when the IMU moves linearly is converted according to the first conversion relation, third IMU data are acquired, wherein the third IMU data comprise: candidate acceleration data of the IMU along three different coordinate axes of the second coordinate system are accumulated in steps S4011-S4014 according to the candidate acceleration data of the IMU along the X axis and the Y axis of the second coordinate system in the third IMU data.

The second historically accumulated data includes an accumulated value of the IMU along X-axis, Y-axis of the second coordinate system. In this embodiment, the accumulated value of the IMU along the X-axis and the Y-axis of the second coordinate system is the speed variation of the IMU in the X-axis and the Y-axis directions, and the forward direction can be determined accordingly.

In the whole accumulation process, when the accumulation times reach a second accumulation threshold value, the accumulated values of the IMU along the X axis and the Y axis of a second coordinate system are determined as second reference data, and otherwise, the second IMU data are continuously acquired for conversion and accumulation.

The value of the second accumulation threshold is not limited, and may be 128, for example. When the accumulation times reach 128 times, the accumulated value of the IMU along the X axis and the Y axis of the second coordinate system is determined as the second reference data, and sufficient speed variation is ensured.

Further, if the updated accumulation times reach a second accumulation threshold value, the speed difference between the current speed and the speed during the first accumulation can be further judged, if the speed difference reaches a specified speed variation, the accumulated values of the IMU along the X axis and the Y axis of the second coordinate system are determined as the second reference data, and if the speed difference does not reach the specified speed variation, the operation of obtaining the second IMU data collected by the IMU during the linear movement is continuously returned, so that sufficient speed variation can be further ensured.

In the process of acquiring the second IMU data acquired by the IMU during linear movement, if the IMU data acquired by the IMU during non-linear movement is acquired, the currently stored second historical accumulated data can be deleted, the second historical accumulated data is accumulated again, the operation of acquiring the second IMU data acquired by the IMU during linear movement is returned, the second historical accumulated data is obtained by accumulating third IMU data acquired by converting the second IMU data acquired by the IMU continuously maintained during linear movement, and the stability of the data is ensured.

Referring to fig. 7, in one embodiment, the step S402 of calculating the second conversion relation according to the second reference data includes the following steps:

s4021: determining the advancing direction of the IMU according to the accumulated value of the IMU along the X axis and the Y axis of a second coordinate system;

s4022: calculating an included angle between the advancing direction of the IMU and a target coordinate axis, wherein the target coordinate axis is a coordinate axis in the second coordinate system, and the direction of the coordinate axis is closest to the advancing direction of the IMU;

s4023: calculating the function relation of the candidate acceleration data of the IMU projected to the advancing direction along the X axis and the Y axis of a second coordinate system respectively according to the included angle;

s4024: and determining the functional relation as the second conversion relation.

Since the IMU is in a linear moving state, the speed variation quantity in the X-axis and Y-axis directions of the second coordinate system can calculate the current speed direction of the IMU, and the speed direction of the IMU is the same as the advancing direction of the IMU, so that the advancing direction of the IMU can be determined by the accumulated value of the IMU along the X-axis and Y-axis directions of the second coordinate system.

Although there may be a deviation between the target coordinate axis direction of the second coordinate system and the advancing direction of the IMU, the conversion is performed through the first conversion relationship, but the conversion only ensures the accuracy of the candidate acceleration data on the Z axis, and cannot make the target coordinate axis direction and the advancing direction of the IMU the same direction, so that it is necessary to compensate for the data deviation caused by the deviation between the target coordinate axis direction and the advancing direction.

The target coordinate axis may be an X-axis or a Y-axis, and taking the X-axis as an example, an angle between the advancing direction of the IMU and the X-axis of the second coordinate system may be calculated. Generally, the X axis or the Y axis may be specified to be in the same direction as the standard advancing direction, and in practice, the specified coordinate axis is a specified coordinate axis because the deviation of the installation posture causes the deviation of the specified coordinate axis from the actual advancing direction, but the deviation is not so large.

And calculating a function relation of candidate acceleration data of the IMU projected to the advancing direction along an X axis and a Y axis of a second coordinate system according to the included angle, and determining the function relation as the second conversion relation.

Based on the second conversion relation, the acceleration data of the IMU along the X axis and the Y axis of the second coordinate system can be projected to the advancing direction, the acceleration data of the IMU along the X, Y axis of the third coordinate system is obtained, and data deviation caused by deviation between the target coordinate axis direction and the advancing direction is compensated.

In this way, when the IMU moves linearly and has no inclination, the acceleration data along the X axis is assumed to be the target coordinate axis, and the acceleration data along the X axis is the acceleration data in the forward direction, among the obtained acceleration data along three different coordinate axes of the third coordinate system, so as to solve the problem of inaccurate data due to the deviation between the X axis direction and the forward direction, where the acceleration data along the Y axis is 0, and the acceleration data along the Z axis is G.

In one embodiment, the step S4021 of determining the advancing direction of the IMU according to the accumulated values of the IMU along the X and Y axes of the second coordinate system includes the steps of:

Referring to FIG. 8, assume that the accumulated value of the IMU along the X-axis of the second coordinate system is X1, the accumulated value of the IMU along the Y-axis of the second coordinate system is Y1, P1 is (0, Y1), and P2 is (X1, 0). Then, Q1 is the target coordinate position corresponding to the accumulated value of the IMU along the X-axis and Y-axis of the second coordinate system, i.e., (X1, Y1); o1 is the coordinate position of the origin in the second coordinate system; then, the direction of O1 to Q1 is the forward direction; the included angle between the O1P1 and the O1Q1 is the included angle between the advancing direction of the IMU and the target coordinate axis.

Assuming that the candidate acceleration data of the IMU along the X axis and the Y axis of the second coordinate system are O1a2 ═ X2, O1a1 ═ Y2, a1 is (0, Y2), and a2 is (X2, 0), respectively, the acceleration data in the forward direction can be obtained by projecting and summing O1a1 and O1a2 onto O1Q1 by using the second transformation relationship, and can be used for determining the driving state of the vehicle in which the IMU is located.

Referring to fig. 9, in one embodiment, the acquiring second IMU data acquired while the IMU is moving linearly in step S300 includes:

s301: obtaining current IMU data acquired by the IMU, wherein the current IMU data comprises: acceleration data of the IMU along three different coordinate axes of a first coordinate system and first angular velocity data of the IMU along a Z axis of the first coordinate system;

s302: converting the first angular velocity data into second angular velocity data according to the first conversion relation;

s303: and checking whether the second angular velocity data is smaller than a set angular velocity value, and if so, determining acceleration data of the IMU in the current IMU data along three different coordinate axes of a first coordinate system as second IMU data.

Since a large acceleration is applied in the direction perpendicular to the forward direction during turning, which seriously affects the calculation of the forward speed direction, when a turn is detected, the record of accumulating the second history accumulated data may be discarded and the accumulation may be performed again.

The second angular velocity data is the angular velocity data of the IMU along the Z-axis of the second coordinate system, which should be 0 if driving straight, and which has a large deviation when turning. Therefore, if the angular velocity data of the IMU along the Z-axis of the second coordinate system is not less than the angular velocity set value, the IMU is considered to be in the non-linear movement state, and the second historical accumulated data may be deleted, accumulated again, and the process returns to step S301 again. The specific value of the angular velocity set value can be determined empirically.

In one embodiment, after compensating the IMU data acquired by the IMU using the first and second transformation relationships, the method further includes:

checking whether the acceleration data of the IMU along the Z axis of the third coordinate system in the compensated IMU data is in a preset value-taking interval, wherein the preset value-taking interval is determined according to the gravity acceleration of the IMU;

if not, deleting the current first conversion relation and second conversion relation, returning to the step S100, and recalculating new first conversion relation and second conversion relation.

The preset value interval is, for example, a range of up-and-down fluctuation of the gravitational acceleration G. Generally, if the difference between the acceleration data of the IMU along the Z axis of the third coordinate system in the compensated IMU data and G is large, that is, the acceleration data exceeds a preset value range, the IMU should tilt, and new first conversion relationship and second conversion relationship need to be recalculated.

In this embodiment, the determination of the IMU tilt is determined based on the acceleration data of the IMU along the Z-axis of the third coordinate system in the compensated IMU data. When the vehicle bumps during running, the target acceleration data generally fluctuates around the magnitude of G rapidly, in order to avoid the influence caused by bumping during the running of the vehicle, whether the acceleration data of the IMU along the Z axis of the third coordinate system in the IMU data after current compensation and the acceleration data of the IMU along the Z axis of the third coordinate system in the IMU data after continuous previous times of compensation are both in a preset value range can be checked, if not, the situation is indicated to be possibly caused by bumping, the situation cannot be judged to be toppled without recalculating a new first conversion relation and a new second conversion relation, and if so, the new first conversion relation and the new second conversion relation are recalculated.

Similarly, when the vehicle runs on a slope with a bump, such as an entrance slope of an underground garage, the vehicle cannot normally detect that the vehicle runs on the slope because the magnitude of the Z-axis acceleration data greatly fluctuates around G during bumping, and the vehicle cannot be judged to be inclined.

The present invention also provides an IMU data compensation apparatus, and in one embodiment, referring to fig. 2, the IMU data compensation apparatus 100 includes:

the first data acquisition module 101 is configured to acquire first inertial sensor IMU data acquired when a moving speed of the inertial sensor IMU is less than a speed threshold;

the first calculation module 102 is configured to calculate a first conversion relationship according to the first IMU data and preset standard IMU data, where the installation posture of the IMU corresponds to a first coordinate system, the first conversion relationship is a conversion relationship between the first coordinate system and a second coordinate system, and the second coordinate system is a coordinate system calibrated based on a gravity direction of the IMU;

a second data obtaining module 103, configured to obtain second IMU data acquired when the IMU moves linearly, and convert the second IMU data into third IMU data according to the first conversion relationship;

a second calculating module 104, configured to calculate a second transformation relationship according to the third IMU data, where the second transformation relationship is a transformation relationship between the second coordinate system and a third coordinate system, and the third coordinate system is a coordinate system calibrated based on a forward direction of the IMU during linear movement;

a data compensation module 105, configured to compensate the IMU data acquired by the IMU using the first and second transformation relationships.

In one embodiment, the first computing module comprises:

In one embodiment of the present invention,

when the first reference data determining unit determines, according to the obtained first IMU data, first reference data required for calculating the first conversion relationship, the first reference data determining unit is specifically configured to:

if the updated accumulation times do not reach a first accumulation threshold value, the accumulated values of the IMU along three different coordinate axes of a first coordinate system are used as first historical accumulation data, and the operation of acquiring the IMU data of the first inertial sensor acquired by the IMU when the moving speed of the IMU is smaller than the speed threshold value is returned; and if the updated accumulation times reach a first accumulation threshold value, determining the ratio of the accumulation values of the IMU along three different coordinate axes of the first coordinate system to the first accumulation threshold value as the first reference data.

In one embodiment, the second calculation module comprises:

a second reference data determination unit for determining second reference data required for calculating the second conversion relationship according to the third IMU data;

In one embodiment of the present invention,

In an embodiment, when the second conversion relation calculating unit calculates the second conversion relation according to the second reference data, the second conversion relation calculating unit is specifically configured to:

and determining the functional relation as the second conversion relation.

In an embodiment, when the second transformation relation calculating unit determines the advancing direction of the IMU according to the accumulated value of the IMU along the X axis and the Y axis of the second coordinate system, the second transformation relation calculating unit is specifically configured to:

and determining the direction from the original point coordinate position to the target coordinate position in the second coordinate system as the advancing direction.

In one embodiment, the second data acquisition module comprises:

and the data determining unit is used for checking whether the second angular velocity data is smaller than a set angular velocity value, and if so, determining the acceleration data of the IMU in the current IMU data along three different coordinate axes of the first coordinate system as the second IMU data.

The implementation process of the functions and actions of each unit in the above device is specifically described in the implementation process of the corresponding step in the above method, and is not described herein again.

For the device embodiment, since it basically corresponds to the method embodiment, reference may be made to the partial description of the method embodiment for relevant points. The above-described embodiments of the apparatus are merely illustrative, wherein the units described as separate parts may or may not be physically separate, and the parts shown as units may or may not be physical units.

The invention also provides an electronic device, which comprises a processor and a memory; the memory stores a program that can be called by the processor; wherein, when the processor executes the program, the IMU data compensation method as described in the foregoing embodiments is implemented.

The embodiment of the IMU data compensation device can be applied to electronic equipment. Taking a software implementation as an example, as a logical device, the device is formed by reading, by a processor of the electronic device where the device is located, a corresponding computer program instruction in the nonvolatile memory into the memory for operation. From a hardware aspect, as shown in fig. 10, fig. 10 is a hardware structure diagram of an electronic device where the IMU data compensation apparatus 100 is located according to an exemplary embodiment of the present invention, and except for the processor 510, the memory 530, the interface 520, and the nonvolatile memory 540 shown in fig. 10, the electronic device where the apparatus 100 is located in the embodiment may also include other hardware generally according to the actual function of the electronic device, which is not described again.

The present invention also provides a machine-readable storage medium on which a program is stored, the program, when executed by a processor, implementing the IMU data compensation method according to any one of the preceding embodiments.

The present invention may take the form of a computer program product embodied on one or more storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having program code embodied therein. Machine-readable storage media include both permanent and non-permanent, removable and non-removable media, and the storage of information may be accomplished by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of machine-readable storage media include, but are not limited to: phase change memory (PRAM), Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), Read Only Memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technologies, compact disc read only memory (CD-ROM), Digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape storage or other magnetic storage devices, or any other non-transmission medium, may be used to store information that may be accessed by a computing device.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. An IMU data compensation method, comprising:

calculating a first conversion relation according to the IMU data of the first inertial sensor and preset standard IMU data, wherein the installation posture of the IMU corresponds to a first coordinate system, the first conversion relation is a conversion relation between the first coordinate system and a second coordinate system, and the second coordinate system is a coordinate system calibrated based on the gravity direction of the IMU;

acquiring second IMU data acquired by the IMU during linear movement, and converting the second IMU data into third IMU data according to the first conversion relation, wherein the acquiring of the second IMU data acquired by the IMU during linear movement comprises: when the angular velocity data of the IMU along the Z axis of the second coordinate system is smaller than a set angular velocity value, determining the acceleration data of the IMU in the current IMU data along three different coordinate axes of the first coordinate system as the second IMU data;

and compensating IMU data acquired by the IMU by using the first conversion relation and the second conversion relation.

2. The IMU data compensation method of claim 1, wherein computing a first conversion relationship from the first inertial sensor IMU data and pre-established standard IMU data comprises:

determining first reference data required for calculating a first conversion relation according to the acquired IMU data of the first inertial sensor;

determining the conversion relationship as the first conversion relationship.

3. The IMU data compensation method of claim 2,

the IMU data of the first inertial sensor comprises initial acceleration data of the IMU along three different coordinate axes of a first coordinate system;

determining first reference data required for calculating a first conversion relationship from the acquired first inertial sensor IMU data, comprising:

if not, storing initial acceleration data of the IMU along three different coordinate axes of a first coordinate system in the currently acquired IMU data of the first inertial sensor as first historical accumulated data, and returning to the operation of acquiring the IMU data of the first inertial sensor acquired when the moving speed of the IMU is smaller than a speed threshold;

if so, calculating the accumulated values of the IMU along three different coordinate axes of the first coordinate system, and updating the accumulated times, wherein the accumulated values of the IMU along the three different coordinate axes of the first coordinate system are obtained by respectively adding the initial acceleration data of the IMU along the three different coordinate axes of the first coordinate system in the currently acquired IMU data of the first inertial sensor and the data along the three different coordinate axes of the first coordinate system in the first historical accumulated data;

4. The IMU data compensation method of claim 1, wherein computing a second transformational relationship from the third IMU data comprises:

5. The IMU data compensation method of claim 4,

determining second reference data required for computing the second conversion relationship from the third IMU data, including:

6. The IMU data compensation method of claim 5, wherein computing a second transformation relationship from the second reference data comprises:

and determining the functional relation as the second conversion relation.

7. The IMU data compensation method of claim 6 wherein determining the IMU heading based on an accumulated value of the IMU along X and Y axes of a second coordinate system comprises:

8. The IMU data compensation method of claim 1, further comprising:

and converting the first angular velocity data into second angular velocity data according to the first conversion relation.

9. An IMU data compensation apparatus, comprising:

the first data acquisition module is used for acquiring first inertial sensor IMU data acquired when the moving speed of the inertial sensor IMU is smaller than a speed threshold;

the first calculation module is used for calculating a first conversion relation according to the IMU data of the first inertial sensor and preset standard IMU data, wherein the installation posture of the IMU corresponds to a first coordinate system, the first conversion relation is a conversion relation between the first coordinate system and a second coordinate system, and the second coordinate system is a coordinate system calibrated based on the gravity direction of the IMU;

the data compensation module is used for compensating IMU data acquired by the IMU by utilizing the first conversion relation and the second conversion relation;

wherein the second data acquisition module comprises:

and the data determining unit is used for determining acceleration data of the IMU along three different coordinate axes of the first coordinate system in the current IMU data as the second IMU data when the angular velocity data of the IMU along the Z axis of the second coordinate system is smaller than a set angular velocity value.

10. The IMU data compensation apparatus of claim 9, wherein the first computation module comprises:

the first reference data determining unit is used for determining first reference data required for calculating a first conversion relation according to the acquired IMU data of the first inertial sensor;

11. The IMU data compensation apparatus of claim 10,

when the first reference data determining unit determines, according to the acquired first inertial sensor IMU data, first reference data required for calculating the first conversion relationship, the first reference data determining unit is specifically configured to:

if so, calculating the accumulated values of the IMU along three different coordinate axes of the first coordinate system, and updating the accumulated times, wherein the accumulated values of the IMU along the three different coordinate axes of the first coordinate system are obtained by respectively adding initial acceleration data of the IMU along the three different coordinate axes of the first coordinate system in the currently acquired IMU data of the first inertial sensor and data along the three different coordinate axes of the first coordinate system in the first historical accumulated data;

12. The IMU data compensation apparatus of claim 9, wherein the second computation module comprises:

13. The IMU data compensation apparatus of claim 12,

checking whether there is currently second historically accumulated data needed to determine second reference data;

if the updated accumulation times do not reach a second accumulation threshold value, the accumulated values of the IMU along the X axis and the Y axis of a second coordinate system are used as second historical accumulation data, and the operation of acquiring the second IMU data acquired when the IMU moves linearly is returned; and if the updated accumulation times reach a second accumulation threshold value, determining the accumulated value of the IMU along the X axis and the Y axis of the second coordinate system as the second reference data.

14. The IMU data compensation apparatus of claim 13, wherein the second transformation relationship calculating unit, when calculating the second transformation relationship based on the second reference data, is specifically configured to:

and determining the functional relation as the second conversion relation.

15. The IMU data compensation apparatus of claim 14, wherein the second transformation relation calculating unit, when determining the advancing direction of the IMU according to the accumulated value of the IMU along the X-axis and the Y-axis of the second coordinate system, is specifically configured to:

16. The IMU data compensation apparatus of claim 9, wherein the second data acquisition module further comprises:

an angular velocity data conversion unit for converting the first angular velocity data into second angular velocity data in accordance with the first conversion relationship.