CN109827507B

CN109827507B - Visual positioning battery replacement method and battery replacement system based on fixed-focus camera

Info

Publication number: CN109827507B
Application number: CN201910059873.2A
Authority: CN
Inventors: 夹磊
Original assignee: NIO Co Ltd
Current assignee: NIO Co Ltd
Priority date: 2019-01-22
Filing date: 2019-01-22
Publication date: 2021-05-25
Anticipated expiration: 2039-01-22
Also published as: CN109827507A

Abstract

The invention relates to the technical field of battery charging and replacing, in particular to a vision positioning battery replacing method and a battery replacing system based on a fixed-focus camera. The invention aims to solve the problem of low precision of the existing visual positioning method. To this end, the visual positioning battery replacement method of the invention comprises the following steps: the method comprises the following steps that a fixed-focus camera acquires an actual image of a reference point from the lower part of a vehicle to be changed; the fixed-focus camera acquires an actual image containing a reference point; determining the offset type of the electric vehicle to be replaced based on the standard image and the actual image of the reference point; calculating the moving distance of the vehicle to be changed needing to be adjusted based on the offset type; adjusting the position of the electric vehicle to be replaced based on the moving distance; and replacing the power battery for the vehicle to be replaced. Through the control mode, the positioning accuracy is improved, and the battery replacement efficiency and the battery replacement stability are improved on the basis of not increasing the cost.

Description

Visual positioning battery replacement method and battery replacement system based on fixed-focus camera

Technical Field

The invention relates to the technical field of battery charging and replacing, in particular to a vision positioning battery replacing method and a battery replacing system based on a fixed-focus camera.

Background

With the popularization of new energy vehicles, how to quickly and effectively supplement energy for the new energy vehicles becomes a concern for various manufacturers and vehicle owners. Taking an electric vehicle as an example, replacing a power battery for the electric vehicle is an effective method for solving the above problems, and the method can replace the power battery for the electric vehicle in a short time, so the method is highly popular among broad service providers and vehicle owners. Generally, the power battery replacement is completed by a battery replacement robot in a battery charging and replacement station, and the battery replacement robot realizes the actions of detaching the power battery in a power shortage state and fixing the power battery in a full battery state on the electric vehicle through the reciprocating movement between a battery replacement platform and a battery bin. In the battery replacement process, the positioning of a vehicle to be replaced is one of the key steps for realizing quick battery replacement, and the positioning precision and the success rate directly determine the battery replacement efficiency and the service quality of a service provider.

Currently, the commonly used positioning methods include mechanical positioning, laser positioning, visual positioning, and the like. The visual positioning has certain application prospect due to the advantages of rich information quantity, high visualization degree and the like. In order to achieve higher positioning accuracy, the visual positioning generally selects an industrial camera to photograph and position a positioning hole at the bottom of the car, and then adjusts the car body through an adjusting mechanism. However, the industrial camera is usually fixed in focus, the view field range is limited to a certain extent, and the chassis height of the vehicle to be replaced is different due to different manufacturing precision, suspension height, tire pressure and the like, so that the working distance of the industrial camera is changed frequently, and the positioning precision of the vehicle to be replaced on the battery replacing platform is affected due to insufficient offset precision of the camera and a standard reference point. In order to solve the problems, the conventional solutions are cameras using electronic zooming, but the cameras using electronic zooming are basically consumer cameras, which do not have the advantages of high protection level of industrial cameras, easy installation and the like, and the cameras using electronic zooming have high cost, so that the cameras are not suitable for application scenes of replacing power batteries.

Accordingly, there is a need in the art for a new method for vision positioning and power conversion based on fixed-focus cameras to solve the above problems.

Disclosure of Invention

In order to solve the above problems in the prior art, that is, to solve the problem of low precision in the existing visual positioning method, the invention provides a visual positioning battery swapping method based on a fixed-focus camera, where the visual positioning battery swapping method includes:

the fixed-focus camera acquires an actual image containing a reference point;

determining the offset type of the electric vehicle to be replaced based on the standard image and the actual image of the reference point;

calculating the moving distance of the vehicle to be changed needing to be adjusted based on the offset type;

adjusting the position of the electric vehicle to be replaced based on the moving distance;

replacing a power battery for the vehicle to be replaced;

the datum point is arranged on the electric vehicle to be replaced; the standard image is obtained in advance; the offset types include a horizontal offset and a height offset.

In a preferred technical solution of the above method for vision positioning and battery replacement based on fixed-focus cameras, two reference points are provided on a chassis of the vehicle to be replaced, and one fixed-focus camera is correspondingly configured for each reference point.

In the preferable technical scheme of the vision positioning battery replacement method based on the fixed-focus camera, the two reference points are symmetrically arranged relative to a symmetric axis in the length direction of the vehicle to be replaced.

In a preferred technical solution of the above method for visually positioning battery replacement based on a fixed-focus camera, the step of determining the offset type of the battery replacement vehicle based on the standard image and the actual image of the reference point further includes:

determining a relative position relationship between the standard position of each reference point and the actual position of the reference point based on the standard image and the actual image;

when the actual positions of the two reference points are located on the same side of the corresponding standard position in the width direction of the vehicle to be subjected to battery replacement, determining that the offset type of the vehicle to be subjected to battery replacement is horizontal offset;

otherwise, determining that the offset type of the electric vehicle to be replaced is height offset.

In a preferred embodiment of the above method for vision positioning battery replacement based on a fixed-focus camera, the step of "calculating a movement distance that needs to be adjusted for the vehicle to be replaced based on the offset type" further includes:

when the offset type is horizontal offset, calculating the moving distance by adopting a method shown in the following formula:

wherein the content of the first and second substances,

represents the moving distance of the vehicle to be changed which needs to be adjusted when the offset type is horizontal offset,

a standard position representing a reference point is an actual distance in the width direction from an actual position of the reference point,

an actual distance in the width direction between a standard position representing another reference point and an actual position of the reference point; and/or

When the offset type is height offset, calculating the moving distance by adopting a method shown in the following formula:

wherein the content of the first and second substances,

represents the moving distance which needs to be adjusted when the offset type is height offset,

the standard position representing another reference point is an actual distance in the width direction from the actual position of the reference point.

In a preferred technical solution of the above method for visually positioning battery replacement based on a fixed-focus camera, the step of "adjusting the position of the vehicle to be replaced based on the moving distance" further includes:

and adjusting the position of the electric vehicle to be replaced in the width direction based on the moving distance.

In the above preferred technical solution of the visual positioning battery replacement method based on the fixed-focus camera, before the step of "replacing the power battery for the vehicle to be replaced", the visual positioning battery replacement method further includes:

lifting the vehicle to be replaced;

acquiring the lifting height and an actual image of the datum point in the lifting process;

judging whether the position of the fixed focus camera deviates or not based on the actual image, the standard image and the lifting height;

and when the judgment result shows that the position of the fixed-focus camera deviates, stopping battery replacement.

In the above preferred technical solution of the method for changing battery for visual positioning based on a fixed-focus camera, "based on the actual image, the standard image, and the lifting height, determining whether the position of the fixed-focus camera is shifted" further includes:

respectively calculating actual distances between the standard positions of the two reference points and the actual positions of the reference points in the width direction of the electric vehicle to be replaced on the basis of the standard image and the actual image;

respectively calculating the ratio of the two actual distances to the lifting height;

comparing the two ratios;

and when the two ratios are not equal or the difference between the two ratios is not in a set threshold interval, judging that the position of the fixed-focus camera deviates.

In the above preferred technical solution of the visual positioning battery replacement method based on the fixed-focus camera, after the step of "replacing the power battery for the vehicle to be replaced", the visual positioning battery replacement method further includes:

descending the vehicle to be changed;

in the descending process, acquiring an actual image of the descending height and the reference point;

judging whether the position of the fixed focus camera is deviated or not based on the actual image, the standard image and the descending height;

In the above preferred technical solution of the method for changing battery for visual positioning based on a fixed-focus camera, "determining whether the position of the fixed-focus camera deviates based on the actual image, the standard image, and the descending height" further includes:

respectively calculating the ratio of the two actual distances to the descending height;

comparing the two ratios;

In the above preferred technical solution of the method for visually positioning and swapping battery power based on a fixed-focus camera, when the determination result indicates that the position of the fixed-focus camera deviates, the method for visually positioning and swapping battery power further includes:

and sending alarm information.

The invention also provides a vision positioning battery replacement system based on the fixed-focus camera, which comprises:

a fixed focus camera for acquiring an actual image containing a reference point;

the classification module is used for determining the offset type of the electric vehicle to be replaced based on the standard image and the actual image of the reference point;

the calculation module is used for calculating the movement distance of the vehicle to be changed needing to be adjusted based on the offset type;

the adjusting module is used for adjusting the position of the electric vehicle to be replaced based on the moving distance;

the execution module is used for replacing a power battery for the vehicle to be replaced;

In the above-mentioned preferred technical solution of the vision positioning battery replacement system based on the fixed-focus cameras, two reference points are provided on a chassis of the vehicle to be replaced, and one fixed-focus camera is correspondingly configured for each reference point.

In the above preferred technical solution of the vision positioning battery replacement system based on the fixed-focus camera, the two reference points are symmetrically arranged with respect to a symmetry axis in the length direction of the vehicle to be replaced.

In the above preferred technical solution of the vision positioning battery replacement system based on the fixed-focus camera, the classification module determines the offset type of the battery replacement vehicle based on the standard image and the actual image of the reference point in the following manner:

In a preferred technical solution of the above-mentioned vision positioning battery replacement system based on the fixed-focus camera, the calculating module calculates a moving distance of the vehicle to be replaced, which needs to be adjusted, based on the offset type by:

wherein the content of the first and second substances,

represents oneThe actual distance in the width direction of the standard position of the reference point from the actual position of the reference point,

wherein the content of the first and second substances,

In the above preferred technical solution of the vision positioning battery replacement system based on the fixed-focus camera, the adjusting module adjusts the position of the vehicle to be replaced based on the moving distance by the following method:

In the above preferred technical solution of the vision positioning battery replacement system based on the fixed-focus camera, the vision positioning battery replacement system further includes:

the lifting module is used for lifting the vehicle to be replaced before the execution module replaces a power battery for the vehicle to be replaced;

the acquisition module is used for acquiring the lifting height of the lifting module in the lifting process;

the fixed-focus camera is further used for acquiring an actual image of the reference point in the lifting process;

the judging module is used for judging whether the position of the fixed focus camera deviates or not based on the actual image, the standard image and the lifting height;

and the control module is used for controlling the vision positioning battery replacement system to stop battery replacement when the judgment result shows that the position of the fixed-focus camera deviates.

In the above preferred technical solution of the vision positioning battery replacement system based on the fixed-focus camera, the determining module determines whether the position of the fixed-focus camera deviates based on the actual image, the standard image, and the lifting height in the following manner:

comparing the two ratios;

In the above preferred technical solution of the vision positioning battery replacement system based on the fixed-focus camera, the lifting module is further configured to lower the vehicle to be replaced after the execution module replaces the power battery for the vehicle to be replaced;

the acquisition module is also used for acquiring the descending height of the lifting module in the descending process;

the fixed focus camera is also used for acquiring an actual image of the reference point in the descending process;

the judging module is further used for judging whether the position of the fixed-focus camera deviates or not based on the actual image;

the control module is further used for controlling the vision positioning battery replacement system to stop battery replacement when the judgment result shows that the position of the fixed-focus camera deviates.

In the above preferred technical solution of the vision positioning battery replacement system based on the fixed-focus camera, the determining module determines whether the position of the fixed-focus camera deviates based on the actual image, the standard image, and the descending height in the following manner:

comparing the two ratios;

and the alarm module is used for sending alarm information when the judgment result is that the position of the fixed-focus camera deviates.

As can be understood by those skilled in the art, in a preferred embodiment of the present invention, the method for replacing a battery based on a fixed-focus camera includes: the fixed-focus camera acquires an actual image containing a reference point; determining the offset type of the electric vehicle to be replaced based on the standard image and the actual image of the reference point; calculating the moving distance of the vehicle to be changed needing to be adjusted based on the offset type; adjusting the position of the electric vehicle to be replaced based on the moving distance; replacing a power battery for the vehicle to be replaced; the datum point is arranged on the electric vehicle to be replaced; the standard image is obtained in advance; the offset types include horizontal offset and height offset.

Through the control mode, the positioning accuracy is improved, the battery replacement efficiency and the battery replacement stability are improved on the basis of not increasing the cost, and the problem of overlarge deviation of the fixed-focus camera caused by the visual field limitation is solved. Specifically, the actual image of the reference point is obtained, whether the offset type of the vehicle to be switched is horizontal offset or height offset is determined based on the actual image and the standard image, so that the moving distance to be adjusted is calculated based on different offset types, and then the position of the vehicle is adjusted based on the moving distance. And because the realization of this control mode is based on present components and parts completely, need not carry out the upgrading transformation to equipment, consequently still controlled the cost of upgrading effectively.

Furthermore, in the process of lifting the vehicle, whether the focus camera deviates in position or not is judged based on the actual image, the standard image and the lifting height, the vision positioning battery replacement method can also effectively check the vision positioning result, judge whether the state of the focus camera is normal or not, and can give an alarm in time when the camera deviates in physical position so as to quickly inform a worker to overhaul, thereby avoiding the occurrence of battery replacement accidents.

Scheme 1, a vision positioning battery replacement method based on a fixed-focus camera, which is characterized in that the vision positioning battery replacement method comprises:

the fixed-focus camera acquires an actual image containing a reference point;

replacing a power battery for the vehicle to be replaced;

The vision positioning battery replacement method based on the fixed-focus camera according to the scheme 2 and the scheme 1 is characterized in that two reference points are arranged on a chassis of the vehicle to be replaced, and each reference point is correspondingly provided with one fixed-focus camera.

Scheme 3 and the vision positioning battery replacement method based on the fixed-focus camera according to scheme 2 are characterized in that the two reference points are symmetrically arranged relative to a symmetric axis in the length direction of the vehicle to be replaced.

Scheme 4, the method for visually positioning and swapping based on a fixed-focus camera according to scheme 2 or 3, wherein the step of determining the offset type of the vehicle to be swapped "based on the standard image and the actual image of the reference point further includes:

The method for vision positioning battery replacement based on the fixed-focus camera according to the claim 5 and the claim 4, wherein the step of calculating the moving distance of the vehicle to be replaced which needs to be adjusted based on the offset type further comprises:

wherein the content of the first and second substances,

wherein the content of the first and second substances,

Scheme 6 and the visual positioning battery replacement method based on the fixed focus camera according to scheme 5, wherein the step of adjusting the position of the battery replacement vehicle based on the moving distance further includes:

Scheme 7, the vision positioning battery replacement method based on the fixed-focus camera according to scheme 2 or 3, wherein before the step of replacing the power battery for the vehicle to be replaced, the vision positioning battery replacement method further includes:

lifting the vehicle to be replaced;

The method for changing battery for visual positioning based on a fixed-focus camera according to claim 8 and 7 is characterized in that the step of determining whether the position of the fixed-focus camera deviates based on the actual image, the standard image and the lifting height further comprises:

comparing the two ratios;

Scheme 9 and the method for visually positioning and replacing battery power based on the fixed-focal-length camera according to scheme 7 are characterized in that after the step of replacing a power battery for the vehicle to be replaced, the method for visually positioning and replacing battery power further comprises the following steps:

descending the vehicle to be changed;

The method according to claim 10 and 9, wherein the step of determining whether the position of the fixed focus camera is shifted based on the actual image, the standard image, and the descending height further includes:

comparing the two ratios;

Scheme 11 and the method for changing battery for visual positioning based on a fixed-focus camera according to scheme 7 are characterized in that when the determination result is that the position of the fixed-focus camera deviates, the method for changing battery for visual positioning further includes:

and sending alarm information.

Scheme 12, a vision location trades electric system based on fixed focus camera, its characterized in that, the vision location trades electric system and includes:

Scheme 13 and the vision positioning battery replacement system based on the fixed-focus camera according to scheme 12 are characterized in that two reference points are arranged on a chassis of the vehicle to be replaced, and each reference point is correspondingly configured with one fixed-focus camera.

Scheme 14 and the vision positioning battery replacement system based on the fixed-focus camera according to scheme 13, wherein the two reference points are symmetrically arranged with respect to a symmetry axis of the vehicle to be replaced in the length direction.

Scheme 15, the vision positioning battery replacement system based on the fixed-focus camera according to scheme 13 or 14, wherein the classification module determines the offset type of the battery replacement vehicle based on the standard image and the actual image of the reference point by:

The vision positioning battery replacing system based on the fixed-focus camera according to the claim 16 and the claim 15 is characterized in that the calculating module calculates the moving distance of the vehicle to be replaced, which needs to be adjusted, based on the offset type by the following method:

wherein the content of the first and second substances,

wherein the content of the first and second substances,

The vision positioning battery replacement system based on the fixed-focus camera according to the claim 17 and the claim 16 is characterized in that the adjusting module adjusts the position of the battery replacement vehicle based on the moving distance by the following method:

Scheme 18, the vision positioning battery replacement system based on the fixed-focus camera according to scheme 13 or 14, wherein the vision positioning battery replacement system further includes:

The vision positioning battery replacement system based on the fixed-focus camera according to claim 19 and claim 18, wherein the determining module determines whether the position of the fixed-focus camera is shifted based on the actual image, the standard image and the lifting height by:

comparing the two ratios;

Scheme 20 and the vision positioning battery replacement system based on the fixed-focus camera according to scheme 18 are characterized in that,

the lifting module is also used for enabling the vehicle to be changed to descend after the execution module changes a power battery for the vehicle to be changed;

The vision positioning battery replacement system according to claim 21 or 20, wherein the determining module determines whether the position of the fixed focus camera is shifted based on the actual image, the standard image, and the descending height by:

comparing the two ratios;

Scheme 22 and the vision positioning battery replacement system based on the fixed-focus camera according to scheme 18, wherein the vision positioning battery replacement system further includes:

Drawings

The invention relates to a vision positioning battery replacement method and a battery replacement system based on a fixed-focus camera, which are described in the following with reference to the accompanying drawings and in combination with an electric automobile. In the drawings:

fig. 1 is a flowchart of a visual positioning battery swapping method based on a fixed-focus camera according to an embodiment of the present invention;

fig. 2 is a bottom view of the electric vehicle of the present invention;

FIG. 3 is a schematic diagram of the arrangement of the fixed-focus camera according to the present invention;

FIG. 4 is a schematic diagram of a standard location of a fiducial in accordance with one embodiment of the present invention;

FIG. 5A is a schematic diagram of an actual position of a reference point when an electric vehicle is in a horizontal offset in one embodiment of the present invention;

FIG. 5B is a schematic diagram illustrating an actual position of a reference point after the position of the electric vehicle is adjusted according to the present invention;

FIG. 6 is a schematic diagram illustrating an actual position of a reference point when an electric vehicle is in a height offset state according to an embodiment of the present invention;

FIG. 7 is a schematic diagram illustrating an actual position of a reference point when an electric vehicle is in a height offset state according to another embodiment of the present invention;

FIG. 8 is a flowchart of a method for vision positioning and battery swapping based on a fixed-focus camera according to another embodiment of the present invention;

fig. 9 is a flowchart of a visual positioning and battery replacement method based on a fixed-focus camera according to still another embodiment of the invention.

List of reference numerals

1. A parking platform; 21. a first industrial camera; 22. a second industrial camera; 3. an electric vehicle; 31. a first reference point; 32. a second reference point; 4. and a power battery.

Detailed Description

Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and are not intended to limit the scope of the present invention. For example, although the present invention is described in conjunction with an electric vehicle, such an application scenario is not invariable, and those skilled in the art can adjust the application scenario, for example, the present invention can also be applied to a vehicle such as a hybrid vehicle, etc. that needs to replace a power battery.

It should be noted that in the description of the present invention, the terms of direction or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, which are merely for convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

Furthermore, it should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Example one

First, referring to fig. 1 to 3, a method for performing a vision positioning battery replacement based on a fixed-focus camera according to the present invention will be described. Fig. 1 is a flowchart of a visual positioning battery replacement method based on a fixed-focus camera in an embodiment of the present invention; fig. 2 is a bottom view of an electric vehicle 3 of the invention; fig. 3 is a schematic diagram of the arrangement of the fixed-focus cameras according to the present invention.

As shown in fig. 1, in order to solve the problem of low precision of the existing visual positioning method, the visual positioning battery replacement method based on the fixed-focus camera of the present invention mainly includes the following steps:

s101, acquiring an actual image containing a reference point by a fixed-focus-distance camera; for example, referring to fig. 2, in one possible embodiment, the chassis of the electric vehicle 3 is provided with two circular hole-shaped reference points, namely a first reference point 31 and a second reference point 32, which are symmetrically arranged on the chassis of the electric vehicle 3 with respect to a longitudinal symmetry axis (i.e., a vertical axis in fig. 2) of the electric vehicle 3; referring to fig. 3, the fixed-focus camera is a fixed-focus industrial camera (hereinafter, referred to as an industrial camera or a camera), and has the advantages of low cost, easy installation, high protection level, and the like. The industrial cameras are provided with two, respectively, a first industrial camera 21 and a second industrial camera 22, which are symmetrically arranged with respect to a symmetry axis in a length direction of the parking platform 1 (i.e., an X-axis in a coordinate system of the parking platform 1 in fig. 3), so that each industrial camera can acquire an actual image of a reference point corresponding thereto by taking a picture.

S102, determining the offset type of the electric automobile 3 based on the standard image and the actual image of the reference point; for example, the offset type of the electric vehicle 3 is determined by comparing the relative positional relationship between the position of the reference point in the actual image and the position in the standard image. The offset type includes a horizontal offset and a height offset, the horizontal offset in this application refers to an offset generated in the horizontal direction mainly by the offset of the electric vehicle 3, in which case the offset in the height direction may be zero or may not be zero, but the influence of the offset generated in the height direction is much smaller than that in the horizontal direction. Similarly, the height offset in the present application means that the offset of the electric vehicle 3 is mainly an offset amount generated in the height direction, in which case the offset amount in the horizontal direction may be zero or may not be zero, but the influence of the offset amount generated in the horizontal direction is much smaller than that in the height direction. The standard image may be images of the reference points acquired by the two industrial cameras when the electric vehicle 3 is at the standard position, or may be images of the reference points acquired by other methods, such as images of the reference points synthesized after calculation by a computational mechanism theory. When the vehicle is in the standard position, each industrial camera may be located directly below the corresponding reference point or not, as long as it is ensured that the image captured by the camera includes the corresponding reference point. The standard position refers to a power switching position of the electric vehicle 3 in an ideal positioning state in the present application, and for example, the standard position may be a position where a symmetry axis in a length direction and a symmetry axis in a width direction of the electric vehicle 3 coincide with an X axis and a Y axis in a coordinate system of the parking platform 1, respectively, and heights between the first industrial camera 21 and the second industrial camera 22 and a chassis are equal. Of course, the standard position may also be any other possible power conversion position, such as a position where the symmetry axis in the length direction of the electric vehicle 3 coincides with the Y axis in the coordinate system of the parking platform 1.

S103, calculating the moving distance of the electric automobile 3 to be adjusted based on the offset type; for example, after the offset type is determined, the movement distance of the electric vehicle 3 in the X-axis direction and/or the Y-axis direction that needs to be adjusted is obtained by calculating the distance between the actual position of the reference point and the standard position in the offset type.

S104, adjusting the position of the electric automobile 3 based on the moving distance; for example, after the moving distance of the electric vehicle 3 in the Y-axis direction that needs to be adjusted is calculated, the position of the electric vehicle 3 in the Y-axis direction is adjusted by using a centering mechanism (e.g., a centering push rod mechanism) of the battery changing platform to push the wheels of the electric vehicle 3 to move.

S105, replacing the power battery 4 for the electric automobile 3; for example, after the position of the electric vehicle 3 is adjusted, it is proved that the positioning is completed, and at this time, the battery replacement robot is controlled to replace the power battery 4 for the electric vehicle 3.

Through the control mode, the positioning accuracy is improved, the battery replacement efficiency and the battery replacement stability are improved on the basis of not increasing the cost, and the problem of overlarge deviation of the fixed-focus camera caused by the visual field limitation is solved. Specifically, the actual image of the reference point is acquired, whether the offset type of the electric vehicle 3 is horizontal offset or height offset is determined based on the actual image and the standard image, so that the moving distance to be adjusted is calculated based on different offset types, and then the position of the vehicle is adjusted based on the moving distance. And because the realization of this control mode is based on present components and parts completely, need not carry out the upgrading transformation to equipment, consequently still controlled the cost of upgrading effectively.

It should be noted that, in order to ensure accurate measurement results, the two cameras need to be calibrated before measurement, and because the two industrial cameras are arranged on the parking platform 1 and the position relationship between the two cameras is not changed, the absolute coordinates between the cameras and the parking platform 1 can be established based on the relative position relationship between the two industrial cameras and the parking platform 1, so as to facilitate subsequent calculation of the movement distance. As shown in fig. 3, knowing the linear distance d between two cameras, the cameras are calibrated by a checkerboard calibration method, and a conversion relationship is established between the coordinate system of the cameras and the coordinate system of the parking platform 1. Wherein, the X-axis direction in the coordinate system of the parking platform 1 corresponds to the length direction of the electric automobile 3, and the Y-axis direction corresponds to the width direction of the electric automobile 3. After the conversion relationship is established, a point in an image acquired by any camera can be converted from the camera coordinate system into the coordinate system of the parking platform 1, so that the position of the point in the coordinate system can be known.

For example, referring to fig. 4, fig. 4 is a schematic diagram illustrating a standard position of a datum point according to an embodiment of the present invention; when the vehicle stops at a standard position, namely the symmetrical axis of the vehicle in the length direction and the symmetrical axis of the vehicle in the width direction are respectively superposed with the X axis and the Y axis in the coordinate system of the parking platform 1, and the heights of the two cameras and the chassis are equal, the two cameras and the chassis are respectively calibrated by checkerboards, and a standard image and a scale of a reference point at the position can be obtained. Therefore, each time the camera acquires an actual image of a reference point, the coordinate of the reference point in the camera coordinate system can be amplified through the scale, so that the actual position and the coordinate of the reference point in the absolute coordinate system and the offset distance of the reference point relative to the standard position in the X-axis direction and the Y-axis direction can be obtained, and the moving distance needing to be adjusted can be obtained based on the offset distance.

The power conversion method of the present invention will be described in detail below with reference to fig. 1 to 7, taking the adjustment of the electric vehicle 3 in the Y-axis direction as an example. Fig. 5A is a schematic diagram of an actual position of a reference point when the electric vehicle 3 is in a horizontal offset state in one embodiment of the present invention; fig. 5B is a schematic diagram of an actual position of the reference point after the position of the electric vehicle 3 is adjusted according to the present invention; FIG. 6 is a schematic diagram illustrating an actual position of a reference point when the electric vehicle 3 is in a height offset state according to an embodiment of the present invention; fig. 7 is a schematic diagram of an actual position of the reference point when the electric vehicle 3 is in a height offset state according to another embodiment of the present invention.

As shown in fig. 4 to 7, in one possible implementation, step S102 may further include: determining a relative positional relationship of the standard position of each reference point and the actual position of the reference point based on the standard image and the actual image; when the actual positions of the two reference points are both located on the same side of the corresponding standard position in the Y-axis direction, determining that the offset type of the electric vehicle 3 is horizontal offset; otherwise, the offset type of the electric vehicle 3 is determined to be a height offset. Specifically, after the actual images of the reference points are acquired, the relative positional relationship between the actual positions of the two reference points in the Y-axis direction and the corresponding standard positions can be known by comparing the coordinates of the reference points in the standard images. As shown in fig. 4 and 5A, the point a and the point B are standard positions of the two reference points in the power exchanging station coordinate system, and the point a 'and the point B' are actual positions of the two reference points in the power exchanging station coordinate system, and as can be seen from fig. 5A, the point a 'and the point B' are respectively located on the left side of the point a and the point B in the Y-axis direction, and it is determined that the offset type of the electric vehicle 3 is a horizontal offset, and the offset type is mainly generated by an offset generated by the electric vehicle 3 in the horizontal direction. Referring to fig. 6 and 7, the actual positions a 'and B' of the two reference points are located outside and inside the corresponding standard positions a and B in the Y-axis direction, respectively, and in both cases, the offset type of the electric vehicle 3 is determined as a height offset, which is mainly generated due to a change in the chassis height of the electric vehicle 3, where fig. 6 corresponds to a case where the reference points are expanded when the chassis of the electric vehicle 3 is lowered, and fig. 7 corresponds to a case where the reference points are contracted when the chassis of the electric vehicle 3 is raised.

With further reference to fig. 4 to 7, in a possible implementation, step S103 may further include:

(i) when the offset type is horizontal offset, the moving distance is calculated by the method shown in the following formula:

in the formula (1), the first and second groups,

represents the moving distance of the electric vehicle 3 which needs to be adjusted when the offset type is horizontal offset,

the actual distance in the Y-axis direction between the standard position representing one reference point and the actual position of the reference point,

representing the standard position of another reference point and the actual position of that reference pointThe actual distance of the position in the Y-axis direction.

For example, as shown in fig. 5A and 5B, when the offset type is horizontal offset, the actual distances between the points a and a' are calculated respectively

And the actual distance between B point and B' point

And the formula (1) is adopted to calculate the moving distance to be adjusted

Then, after the position of the electric vehicle 3 in the Y-axis direction is adjusted based on the moving distance, the coordinate relationship shown in fig. 5B can be obtained, where the point a 'and the point B' do not completely coincide with the point a and the point B, because the chassis of the electric vehicle 3 is also offset in the height direction, but the point a and the point B are symmetrical with respect to the X-axis of the coordinate system of the parking platform 1 when they are set, and the point a 'and the point B' are symmetrical with respect to the midpoint of the line connecting the point a and the point B, it can be considered that the electric vehicle 3 is already centered, that is, the symmetry axis in the length direction of the electric vehicle 3 is already coincident with the X-axis.

(ii) When the offset type is height offset, the moving distance is calculated by adopting a method shown in the following formula:

in the formula (2), the first and second groups,

represents the moving distance of the electric vehicle 3 which needs to be adjusted when the offset type is height offset,

the actual distance in the Y-axis direction from the standard position representing another reference point and the actual position of the reference point.

Similarly to the case of (i), when the offset type is height offset, the actual distances between the points A and A' are calculated by respectively calculating

And the actual distance between B point and B' point

And the formula (2) is adopted to calculate the moving distance to be adjusted

Then, after adjusting the position of the electric vehicle 3 in the Y-axis direction based on the moving distance, a coordinate relationship similar to that of fig. 5B can be obtained, and it can be considered that the electric vehicle 3 is already centered.

After calculating the moving distance, in a possible embodiment, step S104 may further include: based on the movement distance, the position of the electric vehicle 3 in the Y-axis direction is adjusted. For example, after the moving distance is calculated, the position of the electric vehicle 3 in the Y-axis direction is adjusted by adjusting wheels of the electric vehicle 3 through a centering mechanism (e.g., a centering push rod) disposed on the battery replacement platform.

Here, since the parking platform 1 is usually provided with a positioning mechanism for positioning the vehicle in the X-axis direction, such as a V-shaped roller set, the positioning accuracy in the X-axis direction is usually sufficient, and therefore, it is only necessary to adjust the offset of the vehicle in the Y-axis direction. Of course, the positioning mechanism may not be provided in the X-axis direction, and when the positioning mechanism is not provided, the adjustment manner of the electric vehicle 3 in the X-axis direction is similar to that in the Y-axis direction, for example, the distances between the actual positions of the two reference points and the standard position along the X-axis direction are respectively calculated, and the positions of the two reference points are respectively adjusted based on the distances, and the like, which are not described herein again.

Through the control mode, the vision positioning battery replacement method based on the fixed-focus camera can improve the positioning precision, the battery replacement efficiency and the battery replacement stability on the basis of not increasing the cost, and solves the problem of overlarge deviation of the fixed-focus camera caused by the limitation of the visual field. Specifically, the actual image of the reference point is acquired, whether the offset type of the electric vehicle 3 is horizontal offset or height offset is determined based on the actual image and the standard image, so that the moving distance to be adjusted is calculated based on different offset types, and then the position of the vehicle is adjusted based on the moving distance. And because the realization of this control mode is based on present components and parts completely, need not carry out the upgrading transformation to equipment, consequently still controlled the cost of upgrading effectively. The reference points and the industrial camera are symmetrically arranged, so that the operation process is simplified, and the visual positioning method is simple and reliable.

Referring now to fig. 8, another embodiment of the present invention will be described. Fig. 8 is a flowchart of a method for changing battery for visual positioning based on a fixed-focus camera according to another embodiment of the present invention.

As shown in fig. 8, in a possible implementation manner, before step S105, the method for battery swapping based on a fixed-focus camera further includes:

s201, lifting the electric automobile 3; for example, be provided with lifting mechanism on trading the electric platform, lifting mechanism can lift 3 electric automobile that fix a position by a certain height to it trades the electricity to make things convenient for trades electric robot to get into 3 bottoms of electric automobile smoothly and trade.

S202, acquiring actual images of the lifting height and the reference point in the lifting process; for example, in the lifting process, each time the lifting is carried out for a certain height, an actual image comprising the reference point is obtained, and the lifting height corresponding to the image is recorded.

S203, judging whether the position of the industrial camera deviates or not based on the actual image, the standard image and the lifting height; for example, after the actual image and the lift height are acquired, it is determined whether the position of the industrial camera is shifted based on a specific relationship between the actual image, the standard image, and the lift height.

And S204, when the position of the industrial camera deviates according to the judgment result, stopping replacing the battery and sending alarm information. For example, after the position of the industrial camera is determined to be deviated, it is proved that the positioning of the electric vehicle 3 is actually inaccurate, so that the battery replacement action needs to be stopped, and meanwhile, an alarm message (such as an audible and visual alarm) is sent to prompt a worker, so as to avoid the problem caused by the failure of battery replacement.

In a possible implementation manner, step 203 may further include:

calculating actual distances of the standard positions of the two reference points and the actual positions of the reference points in the Y-axis direction respectively based on the standard image and the actual image; respectively calculating the ratio of the two actual distances to the lifting height; comparing the two ratios; and when the two ratios are not equal or the difference between the two ratios is not in the set threshold interval, judging that the position of the industrial camera deviates. Specifically, taking fig. 5B as an example, if fig. 5B is a coordinate relationship between the actual positions of the two reference points and the standard position obtained in the lifting process, the distance between the point a and the point a 'and the distance between the point B and the point B' can be calculated based on the coordinate relationship, and then the ratios of the two distances to the lifting height are calculated respectively. As previously mentioned, in the case of centering, the points a 'and B' are symmetrical with respect to the X axis, so the two ratios calculated in the case of a team should be equal, where the difference between the two ratios is allowed to float in a set threshold interval if mechanical errors are taken into account. Therefore, if the two ratios are equal or the difference between the two ratios is within a certain threshold interval, the positioning accuracy of the electric vehicle 3 is considered to be sufficient, and the two industrial cameras do not have a physical position offset, so that the battery replacement can be continued; if the two ratios are not equal or the difference between the two ratios is not in the set threshold interval, the positioning accuracy of the electric automobile 3 is considered to be insufficient, and the insufficient positioning accuracy is possibly caused by the fact that the two industrial cameras move on the physical positions, the battery replacement should be stopped in time, and alarm information is sent out to prompt a worker to process in time.

Similarly, referring to fig. 9, fig. 9 is a flowchart of a method for vision positioning and battery replacement based on a fixed-focus camera according to still another embodiment of the present invention. After the battery replacement is completed, the battery replacement accuracy can be checked by using a checking method similar to that in the lifting process, and the principle of the method is not described herein again. Namely, after step S105, the method for changing battery based on visual positioning of a fixed-focus camera further includes:

s301, enabling the electric automobile 3 to descend;

s302, acquiring actual images of the descending height and the reference point in the descending process;

s303, judging whether the position of the industrial camera deviates or not based on the actual image, the standard image and the descending height;

and S304, stopping battery replacement and sending alarm information when the position of the industrial camera deviates according to the judgment result.

Wherein step S303 further comprises:

calculating actual distances of the standard positions of the two reference points and the actual positions of the reference points in the Y-axis direction respectively based on the standard image and the actual image; respectively calculating the ratio of two actual distances to the descending height; comparing the two ratios; and when the two ratios are not equal or the difference between the two ratios is not in the set threshold interval, judging that the position of the industrial camera deviates.

By judging whether the industrial camera has position deviation or not based on the actual image, the standard image and the lifting height in the vehicle lifting process, the vision positioning battery replacement method can effectively check the vision positioning result and judge whether the state of the industrial camera is normal or not, and can give an alarm in time when the camera has physical position deviation so as to quickly inform a worker to overhaul and avoid the occurrence of battery replacement accidents. Whether the industrial camera has position deviation or not is judged again in the same mode in the descending process, the judgment result can be further checked, and the stability of the battery replacement process is dually guaranteed. The reference points and the industrial camera are symmetrically arranged, so that the complexity of the checking process is simplified, and the checking process is simple and reliable.

It should be noted that the above preferred embodiments are only used for illustrating the principle of the present invention, and are not intended to limit the protection scope of the present invention. Without departing from the principles of the present invention, those skilled in the art can adjust the setting manner described above, so that the present invention can be applied to more specific application scenarios.

For example, in an alternative embodiment, the moving distance is not obtained in a constant manner, and a person skilled in the art can calculate the moving distance by any calculation method on the premise that the moving distance can be calculated; if the distance value of the remembered point needing to be moved is calculated based on the camera coordinate system, and then the distance value is multiplied by a scale between the camera coordinate system and the battery changing platform coordinate system, the moving distance of the electric automobile 3 needing to be adjusted under the battery changing platform coordinate system is obtained.

As another example, in another alternative embodiment, the set positions of the reference point and the industrial camera are not exclusive, as long as it is ensured that the industrial camera can capture an image of the reference point and calculate the corresponding movement distance. For example, the industrial camera and the reference point may be asymmetrically arranged, and the moving distance may be calculated as long as the relative positional relationship between the reference point and the industrial camera is acquired.

As another example, in another alternative embodiment, the calculation and comparison of the offset to determine the position of the industrial camera based on the actual image, the standard image, and the lift height is not exclusive and can be adjusted by one skilled in the art. For example, in a possible implementation manner, different chassis heights and lifting distances of the electric vehicle 3 may be calibrated in advance, and a two-dimensional comparison table of the actual distance between the actual position of the reference point and the standard position and the lifting height when the different chassis heights are lifted is obtained, so that in the lifting process, the positioning accuracy and which camera has a physical position deviation can be quickly determined by comparing the two ratios with values in the comparison table respectively.

For another example, in another alternative embodiment, during the lifting and lowering process, there may be no checking step, or in case of physical displacement of the camera, the worker may be notified via a mobile terminal (tablet computer, mobile phone, etc.) without sending an alarm message. Such modifications do not depart from the spirit of the invention and are therefore intended to be within the scope of the invention.

A brief description of a possible battery replacement process of the electric vehicle 3 is provided below with reference to fig. 1 to 7.

In a possible embodiment, after the electric vehicle 3 stops at the battery replacing platform, positioning in the X-axis direction is realized through a V-shaped roller set arranged on the battery replacing platform → two industrial cameras respectively take a reference point on the chassis of the electric vehicle 3 and generate an actual image containing two reference points → the actual image is compared with a standard image to obtain a shift type of the electric vehicle 3 → based on the shift type, a moving distance required to be adjusted in the Y-axis direction of the electric vehicle 3 is calculated according to formula (1) or (2 → based on the moving distance, a centering mechanism adjusts the position of the electric vehicle 3 → an adjusted rear lifting mechanism lifts the electric vehicle 3 → obtains actual images of the two reference points in the lifting process, and according to formula (3) or (4), the ratio of the actual distance and the lifting distance of the standard position and the actual position of the two reference points in the Y-axis direction is respectively calculated → whether the two ratios are equal → when equal, continuing to execute the electricity changing process → after the electricity changing is finished, the lifting mechanism drives the vehicle to descend, acquiring actual images of the two reference points in the descending process, respectively calculating the ratio of the actual distance and the descending distance of the standard position and the actual position of the two reference points in the Y-axis direction according to a formula (3) or (4), comparing whether the two ratios are equal → when the two ratios are equal, descending the vehicle to the electricity changing platform → driving the vehicle out of the electricity changing platform, and finishing the electricity changing.

Example two

Correspondingly to the above vision positioning battery replacing method, the invention also provides a vision positioning battery replacing system based on the fixed-focus camera, and the vision positioning battery replacing system comprises:

the fixed-focus cameras are used for acquiring actual images containing reference points, the two reference points are symmetrically arranged on a chassis of the electric automobile 3 relative to a symmetry axis in the length direction of the electric automobile 3, the fixed-focus cameras are fixed-focus industrial cameras which are arranged in two numbers, the two industrial cameras are symmetrically arranged relative to a coordinate system of the parking platform 1, each camera can correspondingly acquire the actual image of one reference point, and when the electric automobile 3 is parked on the level-changing platform, each industrial camera is positioned below the corresponding reference point.

The classification module is used for determining the offset type of the electric automobile 3 based on the standard image and the actual image of the reference point; for example, the classification module may be any device capable of performing image processing, such as an upper computer or a computer, and the upper computer or the computer is capable of analyzing a relative position relationship between an actual position and a standard position of the reference point based on the standard image and the actual image of the reference point, and finally obtaining the offset type of the electric vehicle 3. The standard image is obtained by calibrating the electric vehicle 3 in the standard position in advance by using an industrial camera, and the calibration process is described in the foregoing method and is not described herein again.

And the calculation module is used for calculating the moving distance of the electric automobile 3 required to be adjusted based on the offset type, if the calculation module is also an upper computer or a computer, the upper computer and the computer store preset calculation formulas, and after the classification module determines the offset type, the calculation module can calculate the moving distance of the electric automobile 3 required to be adjusted based on the set formulas.

And the adjusting module is used for adjusting the position of the electric automobile 3 based on the moving distance, and if the adjusting module is a centering push rod mechanism, the centering push rod mechanism can adjust the position of the electric automobile 3 in the Y-axis direction by pushing wheels of the electric automobile 3 based on the calculated moving distance.

And the execution module is used for replacing the power battery 4 for the electric automobile 3, and if the execution module is an automatic guide type power replacing robot or a track guide type power replacing robot, the power replacing robot can reciprocate between the lower part of the electric automobile 3 and the battery bin, so that the action of replacing the power battery 4 for the electric automobile 3 is realized.

Wherein the classification module determines the offset type of the electric vehicle 3 based on the standard image and the actual image of the reference point by:

determining a relative positional relationship of the standard position of each reference point and the actual position of the reference point based on the standard image and the actual image;

when the actual positions of the two reference points are both located on the same side of the corresponding standard position in the width direction of the electric vehicle 3, determining that the offset type of the electric vehicle 3 is horizontal offset;

otherwise, the offset type of the electric vehicle 3 is determined to be a height offset.

Wherein, the calculation module calculates the moving distance of the electric automobile 3 to be adjusted based on the offset type by the following method:

when the offset type is horizontal offset, the moving distance is calculated by the method shown in the following formula:

in the formula (3), the first and second groups,

the actual distance in the width direction between the standard position representing one reference point and the actual position of the reference point,

When the offset type is height offset, the method shown in the following formula is adoptedCalculating a moving distance:

in the formula (4), the first and second groups,

Wherein the adjusting module adjusts the position of the electric vehicle 3 based on the moving distance by:

based on the movement distance, the position of the electric vehicle 3 in the Y-axis direction is adjusted.

Wherein, vision location trades electric system and still includes:

the lifting module is used for lifting the electric automobile 3 before the execution module replaces the power battery 4 for the electric automobile 3, or enabling the electric automobile 3 to descend after the execution module replaces the power battery 4 for the electric automobile 3, if the lifting module is a plurality of chain lifting mechanisms arranged around the parking platform 1, after the electric automobile 3 is lifted by the chain lifting mechanisms to a fixed height, the battery replacement robot can enter the lower part of the electric automobile 3 to replace the power battery 4; when the battery replacement is completed, the electric automobile 3 is lowered to the parking platform 1 through the chain lifting mechanism, so that the electric automobile 3 can be driven out.

The acquisition module is used for acquiring the lifting height or the descending height of the lifting module in the lifting or descending process; if the acquisition module is a distance sensor or an infrared sensor, the lifting height of the lifting module is acquired through the distance sensor or the infrared sensor.

Industrial cameras are also used to acquire actual images of fiducial points during lifting or lowering.

And the judging module is used for judging whether the position of the industrial camera deviates or not based on the actual image, the standard image and the lifting/descending height, and if the judging module can be shared with the computing module, the judging module can also be a separately arranged computer or an industrial personal computer and the like.

And the control module is used for controlling the vision positioning battery replacement system to stop battery replacement when the judgment result is that the position of the industrial camera deviates. For example, the control module is connected with each module through wires or wirelessly to control each module to execute corresponding actions. The control module may be physically a controller dedicated to performing the method of the present invention, or may be a functional module or a functional unit in a control system of the power swapping station.

Wherein, the judging module judges whether the position of the industrial camera deviates or not based on the actual image, the standard image and the lifting/descending height in the following modes:

calculating actual distances in the Y-axis direction between the standard positions of the two reference points and the actual positions of the reference points based on the standard image and the actual image;

respectively calculating the ratio of the two actual distances to the lifting distance or the descending distance of the electric automobile 3;

comparing the two ratios;

and when the two ratios are not equal or the difference between the two ratios is not in the set threshold interval, judging that the position of the industrial camera deviates.

Wherein, vision location trades electric system and still includes:

and the alarm module is used for sending alarm information when the judgment result is that the position of the industrial camera deviates. If the alarm module is an acousto-optic alarm element, the user or the staff is prompted to switch the power failure in a mode of sending alarm information by the acousto-optic alarm element.

So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.

Claims

1. A vision positioning battery replacement method based on a fixed-focus camera is characterized by comprising the following steps:

the fixed-focus camera acquires an actual image containing a reference point;

replacing a power battery for the vehicle to be replaced;

the datum point is arranged on the electric vehicle to be replaced; the standard image is obtained in advance; the offset types include a horizontal offset and a height offset;

and obtaining the moving distance of the vehicle to be changed needing to be adjusted by calculating the distance between the actual position of the reference point and the standard position under the offset type.

2. The vision positioning battery replacement method based on the fixed-focus camera as claimed in claim 1, wherein two reference points are disposed on a chassis of the vehicle to be replaced, and one fixed-focus camera is correspondingly disposed on each reference point.

3. The vision positioning battery replacement method based on the fixed-focus camera as claimed in claim 2, wherein the two reference points are symmetrically arranged with respect to a symmetry axis in a length direction of the vehicle to be replaced.

4. The vision positioning battery replacement method based on the fixed-focus camera as claimed in claim 2 or 3, wherein the step of determining the offset type of the battery replacement vehicle based on the standard image and the actual image of the reference point further comprises:

5. The vision positioning battery replacing method based on the fixed-focus camera as claimed in claim 4, wherein the step of calculating the moving distance of the vehicle to be replaced which needs to be adjusted based on the offset type further comprises:

wherein the content of the first and second substances,

wherein the content of the first and second substances,

6. The visual positioning battery replacement method based on the fixed-focus camera as claimed in claim 5, wherein the step of adjusting the position of the battery replacement vehicle based on the moving distance further comprises:

7. The vision positioning battery replacement method based on the fixed-focus camera as claimed in claim 2 or 3, wherein before the step of replacing the power battery for the vehicle to be replaced, the vision positioning battery replacement method further comprises:

lifting the vehicle to be replaced;

8. The vision positioning and battery replacing method based on the fixed-focus camera as claimed in claim 7, wherein the step of determining whether the position of the fixed-focus camera is shifted based on the actual image, the standard image and the lifting height further comprises:

comparing the two ratios;

9. The vision positioning battery replacement method based on the fixed-focus camera as claimed in claim 7, wherein after the step of replacing the power battery for the vehicle to be replaced, the vision positioning battery replacement method further comprises:

descending the vehicle to be changed;

10. The method as claimed in claim 9, wherein the step of determining whether the position of the fixed focus camera is shifted based on the actual image, the standard image and the descending height further comprises:

comparing the two ratios;

11. The vision positioning battery replacement method based on the fixed-focus camera according to claim 7, wherein when the determination result is that the position of the fixed-focus camera is shifted, the vision positioning battery replacement method further comprises:

and sending alarm information.

12. The utility model provides a vision positioning trades electric system based on fixed focal length camera which characterized in that, vision positioning trades electric system and includes:

the calculation module obtains the moving distance of the vehicle to be changed which needs to be adjusted by calculating the distance between the actual position of the reference point and the standard position under the offset type.

13. The vision positioning battery replacement system based on fixed-focus cameras as claimed in claim 12, wherein two datum points are arranged on a chassis of the battery replacement vehicle, and each datum point is correspondingly configured with one fixed-focus camera.

14. The vision positioning battery replacement system based on the fixed-focus camera as claimed in claim 13, wherein the two reference points are symmetrically arranged with respect to a symmetry axis in a length direction of the battery replacement vehicle.

15. The fixed-focus camera-based visual positioning battery replacement system according to claim 13 or 14, wherein the classification module determines the offset type of the battery replacement vehicle based on the standard image and the actual image of the reference point by:

16. The vision positioning battery replacing system based on the fixed-focus camera as claimed in claim 15, wherein the calculating module calculates the moving distance of the vehicle to be replaced which needs to be adjusted based on the offset type by:

wherein the content of the first and second substances,

wherein the content of the first and second substances,

17. The vision positioning battery replacement system based on the fixed-focus camera as claimed in claim 16, wherein the adjusting module adjusts the position of the battery replacement vehicle based on the moving distance by:

18. The fixed-focus camera-based visual positioning battery replacement system according to claim 13 or 14, further comprising:

19. The vision positioning and battery replacing system based on the fixed-focus camera as claimed in claim 18, wherein the determining module determines whether the position of the fixed-focus camera is shifted based on the actual image, the standard image and the lifting height by:

comparing the two ratios;

20. The vision positioning and battery replacement system based on the fixed-focus camera as claimed in claim 18,

21. The system of claim 20, wherein the determining module determines whether the position of the fixed focus camera is shifted based on the actual image, the standard image and the lowered height by:

comparing the two ratios;

22. The fixed-focus-distance-camera-based visual positioning battery-swapping system as claimed in claim 18, further comprising: