A 2D visual positioning method for vehicle battery replacement

Abstract

The present invention discloses a 2D visual positioning method for vehicle battery swapping, which belongs to the field of battery swapping, including: S1, arranging laser ranging sensors along the front and back of the vehicle battery swapping channel, and arranging a 2D camera on the fork arm of the stacker; S2, parking the vehicle at the calibration position of the battery swapping channel for the first battery swapping to calibrate the initial battery swapping position of the stacker and the position of the vehicle battery; S3, using the ranging of the laser ranging sensor to calculate the deviation angle of the vehicle body relative to the calibration position and the extension and contraction amount of the stacker fork when the focal length of the 2D camera is met during subsequent battery swapping, and controlling the stacker movement accordingly. After the movement is in place, the 2D camera is used to obtain the position information of the vehicle battery; S4, calculating the displacement of the stacker relative to the calibration position and the lifting and lowering displacement of the fork based on the position information, and controlling the stacker to move to the battery swapping position for battery swapping. The present invention enables the device to adapt to the parking position of the vehicle in real time and autonomously change its own posture to replace the vehicle battery.

Description

Technical Field

[0001] The present invention relates to vehicle battery replacement technology, and in particular to a 2D visual positioning method for vehicle battery replacement. Background Art

[0002] At present, after the light trucks on the market drive to the designated location, the posture is corrected by the guidance device, and then the battery is replaced. The general plan is: the vehicle enters the battery replacement platform → the wheel guidance is aligned → the platform lifts the vehicle → the battery replacement RGV takes the old battery from the bottom of the vehicle → consigns it to the battery warehouse → the stacker interacts → the battery replacement RGV returns to the bottom of the vehicle with a fully charged battery → the vehicle is charged → the platform lowers the vehicle → the platform returns to its initial position; this battery replacement method does not include a replacement of the visual system.

[0003] The existing technical solution for replacing light truck batteries is to drive the vehicle into the designated position, correct the vehicle's posture to the template position, and then replace the battery. Due to the heavy load of light trucks, the guiding device is relatively bulky, the battery replacement cycle is relatively slow, the guiding cost is too high, and replacing the battery from the bottom does not conform to the structure of existing light trucks. The battery model needs to be redesigned, and a battery replacement mechanism needs to be added. In addition, due to the vehicle's "load factor" and "tire pressure factor", the positioning accuracy after guiding the body posture is not high, and the replacement failure rate is relatively high. Summary of the Invention

[0004] The purpose of the present invention is to provide a 2D visual positioning method for vehicle battery replacement to simplify the mechanical structure of the vehicle battery replacement system.

[0005] To this end, the present invention provides a 2D visual positioning method for vehicle battery replacement, including: S1, arranging at least one laser ranging sensor along the front and rear of the vehicle battery replacement channel, and arranging a 2D camera on the fork arm of the stacker; S2, parking the vehicle at the calibration position of the battery replacement channel during the first battery replacement, recording the position information of the stacker during calibration, and using the 2D camera to obtain the point information of at least two predetermined feature points on the vehicle battery; S3, using the front and rear laser ranging sensors arranged during subsequent battery replacement to measure the distance and calculate the deviation angle of the vehicle body relative to the calibration, and then calculating the extension and retraction amount of the stacker fork when the focal length of the 2D camera is met, and controlling the action of the stacker accordingly and using the 2D camera to obtain the point information of two predetermined feature points on the vehicle battery after the action is in place; S4, calculating the displacement of the stacker relative to the calibration and the lifting and lowering displacement of the fork based on the point information of the at least two predetermined feature points, controlling the stacker to move to the battery replacement position according to the displacement, and performing battery replacement operations on the vehicle battery according to the lifting and lowering displacement of the fork.

[0006] This invention abandons the battery swap platform's guidance and posture correction method. Instead, it equips the battery swap device with a visual positioning system, allowing the device to adapt to the vehicle's parking position in real time and autonomously change its posture to replace the vehicle's battery. This simplifies the battery swap device structure, reduces equipment failure rates, and improves battery swap efficiency.

[0007] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0009] Figure 1 This is a flow chart of the vehicle battery swap 2D visual positioning method of the present invention;

[0010] Figure 2 It is a schematic diagram of the planar layout of the battery swap system in the vehicle battery swap 2D visual positioning method of the present invention;

[0011] Figure 3 It is a schematic diagram of the vehicle position and posture in the vehicle battery replacement 2D visual positioning method of the present invention;

[0012] Figure 4 It is a schematic diagram of the battery position identified by the 2D camera in the vehicle battery replacement 2D visual positioning method of the present invention. DETAILED DESCRIPTION

[0013] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0014] The present invention uses a 2D camera + laser ranging sensor to take pictures of the vehicle battery, obtain the battery location information, and guide the stacker to the battery replacement position to replace the battery according to the battery location information. This avoids the heavy mechanical task of correcting the vehicle posture through the battery replacement platform, saving construction costs and battery replacement time.

[0015] The vehicle battery swap 2D visual positioning method of the present invention is used in a battery swap station, the layout of which is as follows: Figure 2 As shown, parallel guide rails are provided on both sides of the battery exchange channel. A stacker with a bidirectional telescopic fork arm can move movably on the guide rails. A row of battery pack charging storage racks is provided on the outer side of the guide rails. The battery pack charging storage racks can be divided into a cache battery rack and a charging battery rack.

[0016] The fork arm of the stacker in the present invention can not only be telescopic and movable in both directions, but the telescopic fork arm can also be deflected with the chassis so that the fork arm is extended directly toward the side wall of the vehicle, so that the vehicle battery can be taken out and replaced laterally.

[0017] Stackers that meet the above-mentioned purposes have been disclosed, for example, the stacker structure disclosed in Chinese patent document CN114537208 A (Invention Title: A Vehicle Battery Swapping Station and Battery Swapping Method) by Anhui Juyi Technology Co., Ltd.

[0018] The vehicle battery replacement 2D visual positioning method of the present invention includes: S1, a visual positioning system configuration step, namely, laser ranging sensors arranged in front and behind the same side of the battery replacement channel, and a 2D camera installed on the stacker fork arm and a corresponding visual processing system.

[0019] The vehicle battery replacement 2D visual positioning method of the present invention also includes the following steps S2-S4.

[0020] S2. When swapping batteries for the first time, park the vehicle at the designated location in the battery swap lane to calibrate the battery. Record the stacker's position during calibration and use a 2D camera to capture the position information of two predetermined feature points on the vehicle battery.

[0021] The point information includes the X-coordinate and Z-coordinate of the feature point. Note that the point information obtained by the 2D camera does not include the Y-coordinate.

[0022] The calibration position is an ideal parking position, where the vehicle is parallel to the battery exchange channel, and the position of the stacker on the ground rail ensures that the 2D camera installed on it is located on the central axis of the battery.

[0023] To ensure that the vehicle stops at the designated location, various measures can be employed, such as using parking lines on the ground to guide the vehicle to parking, and providing parking structures on the battery swapping lanes. When the battery swapping vehicle reaches the parking structure, the driver uses their experience to park the vehicle. The parking structure can be, for example, a groove arranged in the ground. Of course, other measures can also be used to assist parking, such as visual guidance systems similar to reversing radar.

[0024] When the vehicle is parallel to the battery exchange channel, the distance measured by laser ranging sensor 1 is consistent with the distance measured by laser ranging sensor 2. The measured distance is the focal length value of the 2D camera, or is greater than the focal length value of the 2D camera. At this time, the fork arm of the stacker is extended or retracted by a displacement, that is, the difference between the measured distance and the focal length value of the 2D camera, so that the camera can focus on the vehicle battery.

[0025] In one embodiment, step S2 includes the following steps:

[0026] S21. First, drive the vehicle into the parking lane and stop after hitting the parking structure, while keeping the vehicle parallel to the battery swap lane;

[0027] S22. The distance measured by the laser ranging sensor 1 is f, and the position measured by the laser ranging sensor 2 is d. At this time, f = d, the vehicle is parallel to the battery exchange channel, and the Y direction information is obtained;

[0028] S23. The camera is located on the central axis of the battery, a coordinate system is established, a photo is taken, two predetermined feature points on the battery are identified, and the coordinate position information of the battery in the X and Z directions and the deflection angle in the Z direction are obtained;

[0029] S24. Send this position information to the lower computer for storage through TCP / IP communication, and run the battery swap mechanism to the battery swap position, which is set as coordinate point O.

[0030] S3. During subsequent battery replacement, the two laser ranging sensors are used to calculate the deviation angle of the vehicle body relative to the calibrated position. Then, the extension and retraction amount of the stacker fork is calculated when the focal length of the 2D camera is met. Based on this, the stacker movement is controlled and after the movement is in place, the 2D camera is used to obtain the point information of two predetermined feature points on the vehicle battery.

[0031] During a subsequent battery swap, the vehicle entered the battery swap lane. When the vehicle touched the parking structure, the driver parked the vehicle based on the vehicle's sensor feedback, maintaining the vehicle in a generally correct parking position. However, during the actual parking process, the vehicle's parking position deviated from the calibrated position, affecting the normal battery swap operation.

[0032] The vehicle battery replacement 2D visual positioning method of the present invention adjusts the stacker by obtaining real-time information on the battery position, thereby enabling battery replacement operations without adjusting the vehicle parking position, thereby simplifying the battery replacement process.

[0033] In one embodiment, step S2 includes the following steps:

[0034] S31, the actual parking position of the vehicle (dashed line) and the calibrated position (solid line) are as follows Figure 3 As shown, the distance measured by laser ranging sensor 1 relative to the previous standard position is de, and the relative distance measured by laser ranging sensor 2 is bd. The distance between the two laser ranging sensors is known to be g. According to tan(a) = (be) / g, the deflection angle a in the Y direction can be obtained at this time. According to cos(a) = Y coordinate / b, the Y coordinate can be obtained.

[0035] S32. Since the 2D camera is mounted on the stacker's fork arm, after deflecting the stacker by an angle a, the fork arm's extension and contraction are adjusted using the Y coordinates to find the camera's focus. This triggers a photo capture to obtain the X and Z coordinate information of two predetermined feature points on the battery, as well as the Z deflection angle.

[0036] S33. This position information is sent to the lower computer via TCP / IP communication, and the actuator moves to the battery replacement position to remove and install the battery.

[0037] S4. Calculate the displacement of the stacker relative to the calibration time and the lifting displacement of the fork based on the position information of the two predetermined feature points, control the stacker to move to the battery replacement position according to the displacement, and perform the battery replacement operation on the vehicle battery according to the lifting displacement of the fork.

[0038] Calculating the displacement of the stacker relative to the calibrated position based on the position information of two predetermined feature points includes: calculating the difference c between the X-axis coordinate of a feature point during battery replacement and the X-axis coordinate of the feature point during calibration; and taking c*cos(a) as the displacement of the stacker relative to the calibrated position.

[0039] The starting point of the fork lifting displacement is calculated by the Z-axis coordinate of the lower feature point of the two feature points of the battery, and its fork lifting displacement value is greater than the difference between the Z-axis coordinates of the two feature points of the battery.

[0040] The battery replacement operation process is as follows: the stacker moves to the battery replacement position according to the displacement, first making the fork arm a distance lower than the lowest point of the battery, then the fork extends to the bottom of the battery pack, lifts the battery pack to a certain height, which is greater than the difference in the Z coordinates of the two predetermined feature points of the battery, so that the battery pack is separated from the truck, and then the fork arm retracts and returns to the side of the battery pack charging storage rack, and places the battery pack on the buffer battery rack. Finally, take out the fully charged battery pack from the charging battery rack and return it to the original position for battery replacement.

[0041] In one embodiment, the present invention is aimed at lateral battery replacement for a 4.2-meter light truck van logistics vehicle, primarily using a stacker mechanism and a charging storage rack to achieve battery replacement. The stacker mechanism lifts and pulls the battery pack from the light truck and then moves it horizontally to the charging storage rack.

[0042] This invention eliminates the need for a mechanical structure that requires a battery swap platform to guide and correct its posture. Instead, it incorporates a visual system into the battery swap device, allowing it to adapt to the vehicle's parking position in real time and autonomously change its posture to replace the vehicle's battery. This simplifies the battery swap device structure, reduces equipment failure rates, and improves battery swap efficiency.

[0043] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, apparatus, or computer program products. Thus, embodiments of the present invention may take the form of entirely hardware embodiments, or embodiments combining software and hardware. Furthermore, embodiments of the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0044] The foregoing description is merely an embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A 2D visual positioning method for vehicle battery swapping, characterized in that: include: S1. Arrange at least one laser ranging sensor along the front and rear of the vehicle battery replacement channel, and arrange a 2D camera on the fork arm of the stacker; S2. When swapping batteries for the first time, park the vehicle at the calibrated position of the battery swap channel, record the position information of the stacker during calibration, and use a 2D camera to obtain the position information of at least two predetermined feature points on the vehicle battery. During the first battery swap, the vehicle at the calibrated position is parallel to the battery swap channel, and the stacker is positioned on the ground rail so that the 2D camera is located on the central axis of the battery, and the distance between the 2D camera on the fork arm and the vehicle battery is equal to its focal length; S3. During subsequent battery swaps, the front and rear laser rangefinders are used to measure the vehicle body's angle of deviation relative to the calibration point. The amount of extension and retraction of the stacker's forks is then calculated to meet the 2D camera's focal length. This information is used to control the stacker's movements. Once the movement is complete, the 2D camera is used to obtain position information for two predetermined feature points on the vehicle's battery. S4, calculating the displacement of the stacker relative to the calibration time and the lifting displacement of the fork according to the position information of the at least two predetermined feature points, controlling the stacker to move to the battery replacement position according to the displacement and performing the battery replacement operation on the vehicle battery according to the lifting displacement of the fork, During subsequent battery replacement, the deviation angle of the vehicle body relative to the calibration time is calculated using the distance measurement of the two laser ranging sensors: a = arctan ((be) / g), where a is the deviation angle of the vehicle body relative to the calibration time, e is the distance measured by the laser ranging sensor 1, b is the distance measured by the laser ranging sensor 2, and g is the distance between the laser ranging sensor 1 and the laser ranging sensor 2. Calculating the amount of telescopic movement of the stacker fork when the focal length of the 2D camera is met includes: y = b cos (a) - d, where y is the telescopic movement of the stacker fork when the focal length of the 2D camera is met, b is the larger of the distance measurement values ​​of the laser ranging sensor 1 and the laser ranging sensor 2, and d is the focal length of the 2D camera. Calculating the displacement of the stacker relative to the calibrated position based on the position information of two predetermined feature points includes: calculating the difference c between the X-axis coordinate of a feature point during battery replacement and the X-axis coordinate of the feature point during calibration; and taking c *cos(a) as the displacement of the stacker relative to the calibrated position.

2. The vehicle battery swap 2D visual positioning method according to claim 1 is characterized in that: A parking structure is provided in the battery-swapping channel, wherein the battery-swapping vehicle stops when it touches the parking structure.

3. The vehicle battery swap 2D visual positioning method according to claim 1, characterized in that: The position information of the predetermined characteristic point of the battery includes the X-coordinate and the Y-coordinate of the characteristic point.

4. The vehicle battery swap 2D visual positioning method according to claim 1, characterized in that: During the first battery swap, the information obtained during vehicle calibration is sent to the lower computer for storage via TCP / IP communication. During subsequent battery swaps, the stacker is first moved to the corresponding position during calibration.

5. The vehicle battery swap 2D visual positioning method according to claim 1, characterized in that: The starting point of the fork lifting displacement is obtained by calculating the Z-direction coordinate of the lower one of the two predetermined characteristic points of the battery, and the fork lifting displacement value is greater than the difference between the Z-direction coordinates of the two predetermined characteristic points of the battery.

6. The vehicle battery swap 2D visual positioning method according to claim 1, characterized in that: The stacker crane's displacement relative to the calibration time and the fork lifting displacement are sent to the lower computer through TCP / IP communication, and the stacker crane is controlled to move to the battery replacement position for battery removal and installation.

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