Automatic mower

Abstract

The present application relates to an automatic mower, which can autonomously move and perform mowing work in a preset working area, comprising: a machine body having a front end; a moving module driving the automatic mower to move; a mowing assembly performing mowing action on the grass in the working area; an image acquisition device arranged at the top of the front end of the machine body and configured to acquire images in the forward direction of the machine body; the field of view angle of the image acquisition device projects on a horizontal plane at a preset height to cover a field of view area of the image acquisition device, the field of view area includes a first field of view boundary away from the front end of the machine body and a second field of view boundary close to the front end of the machine body in the forward direction of the machine body; the image acquisition device is installed according to preset installation parameters, so that the distance between the first field of view boundary and the front end of the machine body is greater than or equal to the response distance of the automatic mower; wherein the response distance is the distance required by the automatic mower to avoid target objects; the target objects include boundaries and obstacles.

Description

Technical Field

[0001] This invention relates to a lawnmower, and more particularly to an automatic lawnmower. Background Technology

[0002] Automatic lawnmowers, capable of autonomously moving and mowing within their designated work area, free users from the tedious task of mowing and reduce manual labor, making them widely popular. However, for an automatic lawnmower to move and mow autonomously within its work area, it needs not only the ability to identify the work area but also the ability to identify obstacles. How to enable an automatic lawnmower to accurately identify obstacles and take appropriate obstacle avoidance measures after detection is a crucial technical problem that must be solved to make automatic lawnmowers more intelligent. Currently, to control the lawnmower within its work area, automatic lawnmowers primarily use boundary wires that emit electrical signals along the edges of the work area to restrict its movement, and collision sensors to detect obstacles. How to enable an automatic lawnmower to move autonomously within its work area without colliding with obstacles, and to identify and react to obstacles, is particularly important for user safety and is therefore a key focus for consumers. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, the problem to be solved by the embodiments of this disclosure is to provide a non-contact obstacle avoidance automatic lawnmower to improve the safety and applicability of the lawnmower.

[0004] An automatic lawnmower, capable of autonomously moving and mowing within a preset working area, comprises: a body having a front end and a rear end along the forward direction of the automatic lawnmower; a moving module for moving the automatic lawnmower; a mowing assembly for cutting grass within the working area; and an image acquisition device disposed on the top of the front end of the body to acquire images along the forward direction of the body; wherein the field of view of the image acquisition device, projected onto a horizontal plane at a preset height, covers an area defined as the field of view of the image acquisition device, the field of view including a first field of view boundary away from the front end of the body and a second field of view boundary closer to the front end of the body along the forward direction of the automatic lawnmower; wherein the image acquisition device is configured to be installed according to preset installation parameters, such that the first field of view boundary is a first distance from the front end of the body, and the second field of view boundary is a second distance from the front end of the body; wherein the first distance is greater than or equal to the response distance of the automatic lawnmower, the response distance being the distance required for the automatic lawnmower to avoid a target object, the target object including boundaries and obstacles; and the second distance is less than or equal to 500 mm.

[0005] By customizing the image acquisition device, the first distance is made greater than or equal to the response distance of the automatic lawnmower, thereby enabling the automatic lawnmower to avoid obstacles and stay within the boundary in the working area, thus improving the safety of the automatic lawnmower.

[0006] In one embodiment, the response distance includes at least one of braking distance and image recognition distance; wherein, the braking distance is the distance traveled by the automatic lawnmower to avoid the target object by braking; the image acquisition device has an image recognition time, and the image recognition distance is the distance traveled by the automatic lawnmower during the image recognition time.

[0007] In one embodiment, the first distance is greater than or equal to the sum of the braking distance of the automatic lawnmower and the image recognition distance, wherein the braking distance is related to at least one of the following motion parameters: braking time and the travel speed of the automatic lawnmower; and the image recognition distance is related to the image recognition time of the image acquisition device and the travel speed of the automatic lawnmower.

[0008] In one embodiment, the driving speed ranges from 0.25m / s to 0.5m / s, the braking time ranges from 50ms to 2s, and the braking distance ranges from 12.5mm to 1000mm; the image recognition time ranges from 50ms to 500ms, and the image recognition distance ranges from 125mm to 250mm.

[0009] In one embodiment, the image recognition time is less than or equal to 0.6s.

[0010] In one embodiment, the braking distance is 25mm.

[0011] In one of the real-time modes, the image recognition distance is 300mm.

[0012] In one embodiment, the first distance and the second distance are determined based on the installation parameters of the image acquisition device, the internal parameters of the image acquisition device, and the preset height h3, respectively; wherein, the installation parameters include at least the installation height h1, the installation distance x0, and the installation angle, wherein the installation height h1 is the height of the image acquisition device above the horizontal ground; the installation distance x0 is the horizontal distance of the image acquisition device from the front end of the body; the installation angle includes the lens rotation angle a3, which is the angle between the lens central axis of the image acquisition device and the vertical direction; the internal parameters of the image acquisition device include the vertical field of view a2.

[0013] In one embodiment, the second distance is less than or equal to a predetermined blind zone threshold.

[0014] In one embodiment, the preset height h3 is in the range of 0mm ≤ h3 ≤ 150mm; the installation height h1 is in the range of 150mm ≤ h1 ≤ 500mm.

[0015] In one embodiment, the vertical field of view a2 of the image acquisition device is in the range of 45°≤a2≤90°.

[0016] In one embodiment, the lens rotation angle a3 of the image acquisition device is in the range of 0 ≤ a3 ≤ 75°.

[0017] In one embodiment, the installation distance x0 is in the range of 0 ≤ x0 ≤ 220 mm.

[0018] In one embodiment, the horizontal installation angle a1 is in the range of 0°≤a1≤180°.

[0019] In one embodiment, the response distance ranges from 135mm to 1250mm.

[0020] In one embodiment, the installation angle further includes a horizontal installation angle a1, which is the angle between the perpendicular line from the center axis of the lens of the image acquisition device and the horizontal line; the installation height h1 ranges from 218mm ≤ h1 ≤ 434mm; the installation distance x0 ranges from 0 ≤ x0 ≤ 83mm; the horizontal installation angle a1 ranges from 0° ≤ a1 ≤ 86°; the vertical field of view a2 ranges from 45° ≤ a2 ≤ 90°; and the lens rotation angle a3 ranges from 52° ≤ a3 ≤ 68°.

[0021] In one embodiment, the installation height h1 = 220 mm; the installation distance x0 = 17 mm; the horizontal installation angle a1 = 38°; the lens rotation angle a3 = 53°; and the vertical field of view a2 = 73°.

[0022] In one embodiment, the first distance is greater than or equal to 800 mm.

[0023] In one embodiment, the blind zone threshold ranges from 50mm to 500mm.

[0024] In one embodiment, the installation angle further includes a horizontal installation angle a1, which is the angle between the perpendicular line from the center axis of the lens of the image acquisition device and the horizontal line; the installation height h1 ranges from 200mm to 400mm; the installation distance x0 ranges from 0 to 40mm; the horizontal installation angle a1 ranges from 30° to 45°; the vertical field of view a2 ranges from 60° to 80°; and the lens rotation angle a3 ranges from 30° to 45°.

[0025] In one embodiment, the installation height h1 = 220 mm; the installation distance x0 = 17 mm; the horizontal installation angle a1 = 38°; the lens rotation angle a3 = 38°; and the vertical field of view a2 = 73°.

[0026] In one embodiment, the first distance is 805 mm.

[0027] In one embodiment, the second distance is less than or equal to 0, wherein the fuselage has a projection on a horizontal plane at a preset height, and the second distance being less than zero includes a second field of view boundary within the projection range.

[0028] In one embodiment, the blind zone threshold is 150 mm.

[0029] In one embodiment, the internal parameters of the image acquisition device also include a horizontal field of view a4, and the value range of the horizontal field of view a4 of the image acquisition device is 60°≤a4≤160°.

[0030] In one embodiment, the ratio of the horizontal field of view a4 to the vertical field of view a2 is 4:3 or 16:9.

[0031] In one embodiment, the horizontal field of view a4 = 130° and the vertical field of view a2 = 73°.

[0032] In one embodiment, the field of view area includes a third field of view boundary located to the left of the direction of travel and a fourth field of view boundary located to the right of the direction of travel along a direction perpendicular to the machine's forward movement; wherein the distance between the third field of view boundary and the fourth field of view boundary is 1.2 to 3 times the width of the automatic lawnmower's body.

[0033] In one embodiment, the width of the fuselage is in the range of 400mm-550mm.

[0034] In one embodiment, the distance between the third field of view boundary and the fourth field of view boundary is determined based on installation parameters, internal parameters of the image acquisition device, and a preset height h3; the installation parameters include at least an installation height h1; the internal parameters of the image acquisition device include a horizontal field of view a4; wherein the horizontal field of view a4 is configured to determine the detection distance of the image acquisition device along the width direction of the fuselage.

[0035] In one embodiment, the installation height h1 is in the range of 150mm ≤ h1 ≤ 500mm, and the installation height h3 is in the range of 0mm ≤ h3 ≤ 150mm.

[0036] In one embodiment, the horizontal field of view a4 of the image acquisition device is in the range of 60°≤a4≤160°. Attached Figure Description

[0037] The objectives, technical solutions, and beneficial effects of the present invention described above can be clearly obtained through the following detailed description of specific embodiments that enable the implementation of the present invention, in conjunction with the accompanying drawings.

[0038] The same reference numerals and symbols in the accompanying drawings and the specification are configured to represent the same or equivalent elements.

[0039] Figure 1 This is a schematic diagram of the structure of an automatic lawnmower provided by the present invention;

[0040] Figure 2 This is a schematic diagram of the field of view of the image acquisition device provided by the present invention;

[0041] Figure 3 This is a schematic diagram of the field of view of the image acquisition device applied to an automatic lawnmower provided by the present invention, wherein the field of view boundary near the front of the machine body is tangent to or at least partially coincides with the front of the machine body;

[0042] Figure 4 The present invention provides that has Figure 2 Side view of an automatic lawnmower within the field of view of the image acquisition device;

[0043] Figure 5 The present invention provides that has Figure 2 A top view of an automatic lawnmower within the field of view of the image acquisition device;

[0044] Figure 6 This is a schematic diagram of the field of view of the image acquisition device provided by the present invention, applied to an automatic lawnmower, projected onto a plane where the grass height is greater than 0.

[0045] Figure 7 This is a schematic diagram of an image acquisition device installed on an automatic lawnmower in a first installation method;

[0046] Figure 8 This is a schematic diagram of an image acquisition device installed on an automatic lawnmower using a second mounting method.

[0047] Figure 9 This is a schematic diagram of an image acquisition device installed on an automatic lawnmower using a third mounting method.

[0048] Figure 10 This is a schematic diagram of the image acquisition device installed on an automatic lawnmower using the fourth installation method;

[0049] Figure 11 This is a schematic diagram of the image acquisition device installed on an automatic lawnmower using the fifth installation method;

[0050] Figure 12 This is a schematic diagram of an image acquisition device that is mounted on an automatic lawnmower without rotating around an axis.

[0051] Figure 13 This is a schematic diagram of the image acquisition device under the first extreme installation condition;

[0052] Figure 14 This is a schematic diagram of the image acquisition device under the second extreme installation condition;

[0053] Figure 15 This is a schematic diagram of an image acquisition device considering boundary constraints.

[0054] Figure 16 yes Figure 15 A schematic diagram of the projection of the framing light from the image acquisition device onto a vertical plane. Detailed Implementation

[0055] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more definite definition of the scope of protection of the present invention. The following embodiments can be appropriately combined with each other. In the accompanying drawings and description, the same reference numerals and symbols in different embodiments are configured to represent the same or equivalent elements.

[0056] Reference Figure 1 In one embodiment of this application, an automatic lawnmower 100 is provided. The automatic lawnmower moves autonomously within a preset working area and performs lawn mowing autonomously. The automatic lawnmower 100 includes: a body 101, a moving module 105, a mowing component 104, and a control module 103; the moving module 105 and the mowing component 104 are electrically connected to the control module 103.

[0057] Among them, the fuselage 101 has a front end 106;

[0058] The moving module 105 is mounted on the machine body and is configured to move the automatic lawnmower 100, for example, to move the automatic lawnmower within a preset working area.

[0059] Specifically, the mobile module 105 includes a walking wheel and a drive motor that drives the walking wheel to move, with the output end of the drive motor connected to the walking wheel.

[0060] The mowing component 104 is mounted on the machine body and configured to perform preset mowing actions, such as cutting grass within the work area.

[0061] The control module 103 is installed on the machine body and is configured to control the movement module 105 to drive the automatic lawnmower 100 to move, and control the mowing component 104 to perform the mowing work;

[0062] Specifically, the mowing assembly 104 includes a blade disc and a cutting motor that drives the blade disc to rotate. The blade disc is provided with at least one blade. The blade disc rotates under the drive of the cutting motor, thereby driving the blade on it to cut the grass.

[0063] Furthermore, the automatic lawnmower 100 may also include a protective mechanism (not shown) configured to protect the blade disc, such as a protective cover or the housing of the body 101.

[0064] Furthermore, the automatic lawnmower 100 may also include a height adjustment mechanism (not shown in the figure) for adjusting the height of the cutter head to different heights, thereby obtaining different grass heights.

[0065] Furthermore, the automatic lawnmower also includes an image acquisition device 102, which is located at the top front of the machine body and configured to acquire the forward direction of the machine body 101 (e.g., Figure 1 The image shown by the middle arrow;

[0066] The field of view (also known as field of view angle) of the image acquisition device 102 is the area covered by the horizontal plane at a preset height. The field of view area includes a first field of view boundary away from the front of the fuselage and a second field of view boundary near the front of the fuselage along the direction of the fuselage's movement. The preset height here may be set according to the height of grass (referred to as grass height) or according to the height of obstacles.

[0067] For ease of understanding, the following discussion assumes a preset height of 0, meaning the image acquisition device's field of view can be directly projected onto a horizontal surface, and combines this with... Figure 5 A brief description of the first and second field-of-view boundaries:

[0068] Reference Figure 5The field of view coverage of the image acquisition device is projected onto a horizontal ground at a preset height, such as the height of grass or the height of obstacles, and includes a first field of view boundary FG (or FDG) away from the front of the fuselage and a second field of view boundary BE (or BCE) closer to the front of the fuselage along the direction of flight.

[0069] It is understandable that when the preset height (HI) is greater than 0, the reference... Figure 6 The field of view of the image acquisition device, projected onto a plane with a preset height greater than 0, extends along the direction of flight of the aircraft towards the second field of view boundary PQ (or PMQ) near the front of the aircraft; while the field of view of the image acquisition device, projected onto a horizontal plane with a grass height greater than 0, extends along the direction of flight of the aircraft away from the front of the aircraft towards the first field of view boundary passing through point H, and is parallel to PQ and the first field of view boundary (e.g., ...). Figure 5 (as shown in FG).

[0070] The image acquisition device is installed according to preset installation parameters, such that the first field of view boundary is a first distance from the front end of the machine body, and the second field of view boundary is a second distance from the front end of the machine body. The first distance is greater than or equal to the response distance of the automatic lawnmower, which represents the distance required for the automatic lawnmower to avoid a target object, including boundaries and / or obstacles; and the second distance is less than or equal to 500mm.

[0071] By controlling the first distance to be greater than or equal to the response distance of the automatic lawnmower, it is beneficial for the automatic lawnmower to detect boundaries and / or obstacles in a timely manner, thus giving it sufficient time to complete the avoidance maneuver. At the same time, by controlling the second distance to be less than or equal to 500mm, it is beneficial to reduce the range of the detection blind zone of the image acquisition device, thereby reducing the impact of the detection blind zone of the image acquisition device on the safety of the automatic lawnmower, preventing the automatic lawnmower from colliding with boundaries and / or obstacles due to the inability to recognize the boundaries and / or obstacles around the machine, and improving the safety of the automatic lawnmower.

[0072] The aforementioned response distance includes at least one of braking distance and image recognition distance; wherein, the braking distance is the distance traveled by the automatic lawnmower to avoid the target object by braking; the image acquisition device has an image recognition time, and the image recognition distance is the distance traveled by the automatic lawnmower within the image recognition time.

[0073] For example, when the image processing capability of an automatic lawnmower is poor, causing the weight of image recognition distance to be much greater than that of other factors (such as braking system performance), such as when the automatic lawnmower has excellent braking performance, making the braking distance much less than a threshold (e.g., 10mm), the response distance is approximately equal to the image recognition distance. Conversely, when the braking performance of an automatic lawnmower is poor, causing the weight of braking distance to be much greater than that of other influencing factors (such as image processing performance), such as when the automatic lawnmower's image acquisition device can instantly (e.g., image recognition time within tens of milliseconds), the weight of image recognition factors is often negligible, and the response distance is approximately equal to the braking distance.

[0074] It is evident that the installation parameters of the image acquisition device need to take into account the machine braking distance and visual processing speed. In other words, the machine braking distance and visual processing speed will affect the installation of the image acquisition device.

[0075] In this disclosure, when an automatic lawnmower performs mowing operations in a work area, since the work area is usually enclosed by boundary lines and may contain obstacles such as stones, trees, and small animals, the automatic lawnmower can identify and respond to these boundary lines and obstacles using visual technology. In other words, when the automatic lawnmower encounters a boundary line or obstacle in the work area, it can detect the boundary line and obstacle using an image acquisition device. Upon detecting or identifying a boundary line or obstacle, the machine's response strategy, based on its own needs or program settings, mainly includes one of the following strategies:

[0076] Strategy 1: Adopt a braking approach;

[0077] Strategy 2: Use a turning method, such as an arc turn or a reverse turn followed by a turn;

[0078] Strategy 3: Use a "braking + steering" approach, such as braking while steering.

[0079] Therefore, the aforementioned response distance is related to at least one of the automatic lawnmower's braking distance or turning distance.

[0080] In one embodiment, when the automatic lawnmower detects a boundary line or obstacle in front of it, for example, when the boundary line or obstacle appears at the first field of view of the image acquisition device, if the automatic lawnmower uses braking to avoid going out of bounds or colliding with the obstacle, the response distance is related to the braking distance of the automatic lawnmower. The braking distance of the automatic lawnmower refers to the distance that the automatic lawnmower moves during braking. For example, the braking distance can be the distance that the machine travels from braking to a complete stop during its movement.

[0081] In one embodiment, the image acquisition device is installed according to preset installation parameters, such that the distance between the first field of view boundary and the front end of the machine body is greater than or equal to the braking distance of the automatic lawnmower.

[0082] In one embodiment, the braking distance is related to the travel speed of the automatic lawnmower, which can be detected by a speed sensor (e.g., a Hall sensor) mounted on the moving module. In another embodiment, the automatic lawnmower also includes an acceleration sensor mounted on the machine body and connected to the control module. The acceleration sensor is configured to detect the acceleration information of the automatic lawnmower. In this case, the braking distance can be determined based on the machine's travel speed and the acceleration during braking. For example, the acceleration sensor sends the detected speed information, especially the acceleration during braking, to the control module. The control module calculates the braking distance based on the acceleration information detected by the acceleration sensor and the travel speed of the automatic lawnmower.

[0083] Alternatively, the automatic lawnmower includes a speed sensor mounted on the wheels of the machine and connected to a control module. The speed sensor is configured to detect the speed information of the automatic lawnmower and send it to the control module. The control module is also configured to calculate the acceleration based on the detected speed information of the automatic lawnmower, especially the speed during braking, and to calculate the braking distance based on the speed and acceleration.

[0084] Considering that the acceleration during braking may be constantly changing, on the one hand, the acceleration sensor needs to continuously detect, which increases the hardware requirements of the acceleration sensor. On the other hand, the control module (e.g., processor) needs to calculate based on the real-time acceleration detected by the sensor during the acceleration phase, which places higher demands on the hardware and computing power of the control module. In one embodiment, to save costs, for example, an automatic lawnmower may not have an acceleration sensor and / or use a control module with lower processor performance. The braking distance can be determined based on the automatic lawnmower's travel speed and braking time, where the braking time is related to the braking capability of the machine's braking system. The better the machine's braking capability, the shorter the braking time. The braking time can usually be obtained through experimental testing.

[0085] In one embodiment, the driving speed ranges from 0.25 m / s to 0.5 m / s;

[0086] In one embodiment, the braking time ranges from 50ms to 2s.

[0087] The braking distance, determined based on the automatic lawnmower's travel speed and braking time, ranges from approximately 12.5 mm to 1000 mm.

[0088] For example, the driving speed ranges from 0.25m / s to 0.5m / s; when the braking time is 50ms, the braking distance is in the range of 12.5mm to 25mm; while when the braking time is 2s, the braking distance ranges from approximately 0.5m to 1m.

[0089] When an automatic lawnmower detects a boundary line or obstacle in front of it, such as when the boundary line or obstacle appears on the first field of view of the image acquisition device, the boundary line can be used to define the working area of ​​the automatic lawnmower. If the automatic lawnmower uses a turning method to avoid going out of bounds, avoid obstacles, or needs to walk along the edge, the response distance is related to the turning distance of the automatic lawnmower. The turning distance of the automatic lawnmower refers to the distance that the automatic lawnmower moves during the turning process. For example, when turning in an arc, the turning distance can be the projected distance of the distance the automatic lawnmower travels from the start of the turn to the completion of the turn along the width direction of the machine body, or the turning radius corresponding to the arc traveled by the automatic lawnmower from the start of the turn to the completion of the turn.

[0090] In one embodiment, the image acquisition device is installed according to preset installation parameters, such that the distance between the first field of view boundary and the front end of the machine body is greater than or equal to the turning distance of the automatic lawnmower.

[0091] In one embodiment, the aforementioned turning distance is related to the machine's speed before or during the turn, as well as the turning angle.

[0092] It should be noted that the aforementioned boundary lines can be physical boundaries, such as cables or fences, or virtual boundaries, such as the boundaries of the working area pre-marked on the map when an automatic lawnmower creates a map; this disclosure does not limit this.

[0093] Of course, if the automatic lawnmower detects a boundary line or obstacle in front of it, such as when the boundary line or obstacle appears on the first field of view of the image acquisition device, the boundary line can be used to define the working area of ​​the automatic lawnmower. If the automatic lawnmower uses the "braking + steering" method to avoid going out of bounds, avoid obstacles, or needs to walk along the edge, the response distance is related to the braking distance and turning distance of the automatic lawnmower.

[0094] In one embodiment, the image acquisition device is installed according to preset installation parameters, such that the distance between the first field of view boundary and the front end of the machine body is greater than or equal to the sum of the braking distance and turning distance of the automatic lawnmower.

[0095] Additionally, it should be noted that when avoiding going out of bounds or colliding with obstacles, whether the automatic lawnmower adopts a steering or braking method, or a "braking + steering" method, is set by the internal program of the automatic lawnmower, and this application does not limit this.

[0096] It should be understood that, in order to avoid collision damage, when determining the distance between the first field of view boundary and the front of the fuselage, especially when the front of the fuselage has an arc-shaped profile, the end edge point of the front of the fuselage along the forward direction is used as the measurement endpoint to determine the distance to the first field of view boundary.

[0097] It should be noted that, considering that the mowing components of an automatic lawnmower are located at the center of the bottom of the machine or at a certain distance off the center during actual operation, the machine can extend beyond the set boundary line during mowing.

[0098] Therefore, in one embodiment, when a boundary line appears in front of the automatic lawnmower, if the automatic lawnmower uses braking to avoid going out of bounds, the response distance is also related to the aforementioned set distance of the automatic lawnmower.

[0099] In one embodiment, the image acquisition device is installed according to preset installation parameters, such that the distance between the first field of view boundary and the front end of the machine body is greater than or equal to the difference between the braking distance of the automatic lawnmower and the set distance, or the distance between the first field of view boundary and the front end of the machine body is greater than or equal to the absolute value of the difference between the braking distance of the automatic lawnmower and the set distance.

[0100] Similarly, in one embodiment, when a boundary line appears in front of the automatic lawnmower, if the automatic lawnmower uses a turning method to avoid going out of bounds or turns to walk along the edge, the response distance is also related to the aforementioned set distance of the automatic lawnmower.

[0101] In one embodiment, the image acquisition device is installed according to preset installation parameters, such that the distance between the first field of view boundary and the front end of the machine body is greater than or equal to the difference between the turning distance of the automatic lawnmower and the set distance, or the distance between the first field of view boundary and the front end of the machine body is greater than or equal to the absolute value of the difference between the turning distance of the automatic lawnmower and the set distance.

[0102] In one embodiment, depending on the machine model and the location of the mowing device, the aforementioned setting distance can be selected within the range of 0.1m-1m.

[0103] Considering that image acquisition devices have image processing time (or image recognition time), automatic lawnmowers capture images in their forward direction using image acquisition devices. When objects appear in the image, such as boundary lines or obstacles, and the automatic lawnmower is still moving, an image recognition distance will occur. The image recognition distance refers to the distance the automatic lawnmower travels during the image recognition time. It is easy to understand that the image recognition distance is related to the image processing time (or image recognition time) and the speed of the automatic lawnmower.

[0104] The image processing time can be characterized by the frame rate of the image acquisition device. For example, a frame rate of 3fps means 3 shots per second, or approximately 0.3s / frame, in which case the image processing time is considered to be 0.3s. If the frame rate is 4fps, it means 4 shots per second, or 0.25s / frame, in which case the image processing time is also considered to be 0.25s. An image recognition time is defined to characterize the time it takes for the image acquisition device to identify the target object from the image. Since image recognition is usually based on the comparison of multiple images, the image recognition time is an integer multiple (and greater than or equal to 2) of the image processing time. In one embodiment, the image recognition time is the time to achieve image recognition based on the comparison of two images, that is, twice the image processing time. Therefore, for a frame rate of 3fps, the image processing time is 0.3s, and the image recognition time is 0.6s, while for a frame rate of 4fps, the image recognition time is 0.5s.

[0105] To prevent potential safety risks during the automatic lawnmower's identification of objects in the work area and to ensure the safe operation of the machine, in one embodiment, the response distance is related to the image recognition distance described above.

[0106] In one embodiment, the image acquisition device is installed according to preset installation parameters, such that the first distance is greater than or equal to the image recognition distance of the automatic lawnmower.

[0107] It is understandable that image processing time is related to the processing power of the image acquisition device. Generally, the stronger the processing power of the image acquisition device, the shorter the image processing time and the smaller the image recognition distance.

[0108] In one embodiment, the image processing time ranges from 0.2s to 0.5s, and the image recognition time ranges from 0.4s to 1s. Further, the image processing time is less than or equal to 0.3s, and the image recognition time is less than or equal to 0.6s.

[0109] In one embodiment, the image recognition distance is approximately equal to the product of the image recognition time and the speed of the automatic lawnmower.

[0110] In one embodiment, when the image processing time ranges from 0.2s to 0.5s and the driving speed of the lawnmower ranges from 0.25m / s to 0.5m / s, it can be concluded that the image recognition distance ranges from 100mm to 500mm.

[0111] In one embodiment, the frame rate is 15fps, meaning 15 frames per second, or 67ms / frame. Therefore, the image processing time is 67ms. The image recognition time is the time required to recognize an image based on a single image, which is twice the image processing time. Thus, the image recognition time is 134ms. In this disclosure, the image processing time ranges from 50ms to 500ms, and the lawnmower's speed ranges from 0.25m / s to 0.5m / s. Therefore, the image recognition distance ranges from 125mm to 250mm.

[0112] Similarly, it should be noted that, considering that when an automatic lawnmower is actually in operation and when a boundary line appears in front of it, the lawnmower's mowing component is set at the center of the bottom of the machine body or at a certain distance off the center, or at a reserved distance from the front of the machine body. Therefore, when the automatic lawnmower is mowing, the machine body can go a certain distance beyond the boundary line. The machine body can usually go a set distance beyond the boundary line.

[0113] Therefore, in one embodiment, when a boundary line appears in front of the automatic lawnmower, if the automatic lawnmower uses braking to avoid going out of bounds, the response distance can also be related to the aforementioned set distance of the automatic lawnmower.

[0114] At this time, the image acquisition device is installed according to the preset installation parameters, such that the first distance is greater than or equal to the sum of the braking distance of the automatic lawnmower and the image recognition distance of the image acquisition device minus the set distance; or the distance between the first field of view boundary and the front end of the machine body is greater than or equal to the absolute value of the sum of the braking distance of the automatic lawnmower and the image recognition distance of the image acquisition device minus the set distance.

[0115] Similarly, in one embodiment, when a boundary line appears in front of the automatic lawnmower, if the automatic lawnmower uses a turning method to avoid going out of bounds or turns to walk along the edge, the response distance is also related to the aforementioned set distance of the automatic lawnmower.

[0116] At this time, the image acquisition device is installed according to the preset installation parameters, such that the first distance is greater than or equal to the sum of the turning distance of the automatic lawnmower and the image recognition distance of the image acquisition device minus the set distance; or, the distance between the first field of view boundary and the front end of the machine body is greater than or equal to the absolute value of the sum of the turning distance of the automatic lawnmower and the image recognition distance of the image acquisition device minus the set distance.

[0117] In order to ensure mowing efficiency, the automatic lawnmower in this disclosure adopts high-speed movement, which means that the travel speed is between 0.45m / s and 0.5m / s, and the deceleration is achieved by braking with a gearbox, with a braking time of about 50ms.

[0118] For example, if the driving speed is set to 0.5 m / s, the braking time to 50 ms, and the braking distance to approximately 25 mm; and the image processing time is set to 0.3 s, then the image recognition time is 0.6 s, the driving speed is set to 0.5 m / s, and the image recognition distance is set to approximately 300 mm.

[0119] It is evident that, since the image recognition time is longer than the braking time, the image recognition distance is much larger than the braking distance, meaning that the image recognition distance is often not negligible.

[0120] Therefore, in scenarios where a boundary line or obstacle appears in front of the automatic lawnmower, and the automatic lawnmower uses braking to avoid going out of bounds or colliding with the obstacle, the first distance is greater than or equal to the sum of the automatic lawnmower's braking distance and the image recognition distance of the image acquisition device. It can be understood that the braking distance is related to at least one of the following motion parameters: braking time and the automatic lawnmower's travel speed; the image recognition distance is related to the image recognition time or image processing time of the image acquisition device and the automatic lawnmower's travel speed.

[0121] Considering the varying processing and braking capabilities of image acquisition devices used in the automatic lawnmower industry, in order to improve the effectiveness and accuracy of image recognition and the safety of the machine, in one embodiment, a response distance of approximately 2 seconds is reserved for an automatic lawnmower operating at a normal speed (3m / s) from the front of the machine body to the farthest point in the direction of forward vision. For example, the reserved response distance is approximately 600mm.

[0122] In one embodiment, the first distance is 805 mm.

[0123] Of course, when a boundary line or obstacle appears in front of the automatic lawnmower, and the automatic lawnmower uses a turning method to avoid going out of bounds, avoid obstacles, or needs to walk along the edge, the first distance is greater than or equal to the sum of the turning distance of the automatic lawnmower and the image recognition distance of the image acquisition device.

[0124] In this disclosure, the first distance and the second distance are related to the installation parameters of the image acquisition device, the internal parameters of the image acquisition device itself, and the preset height h3.

[0125] The installation parameters include installation orientation and installation angle. The installation orientation includes, for example, installation height h1 and installation distance X0. Installation height h1 is the height of the image acquisition device from the horizontal ground. For example, when the image acquisition device is a camera, installation height h1 is the height of the camera from the horizontal ground; this height can be the distance between the center point of the camera lens and the horizontal ground. Installation distance X0 is the horizontal distance of the image acquisition device from the front end of the machine body. For example, when the image acquisition device is a camera, installation distance is the distance between the center point of the camera lens and the front end of the machine body. It should be noted that when the automatic lawnmower's body is irregularly shaped, the front end here can be, for example, the edge of the front end of the machine body.

[0126] The aforementioned installation angle includes the lens rotation angle a3, which is the angle between the central axis of the lens of the image acquisition device and the vertical direction.

[0127] In one embodiment, the installation angle may further include a horizontal installation angle a1, which is the angle between the perpendicular line from the center axis of the lens of the image acquisition device and the horizontal line; in other words, the horizontal installation angle a1 is the angle between the line connecting the center point of the image acquisition device and its mounting point on the body and the horizontal line.

[0128] It is understood that the above-mentioned installation distance x0 is related to the horizontal installation angle a1, or in other words, the installation distance x0 can be determined based on the horizontal installation angle a1.

[0129] Reference Figure 7 It can be seen that the installation distance x0 can be determined by the trigonometric relationship between the cantilever length L (OA) and the horizontal installation angle a1, or by the trigonometric relationship between the installation height h1, the fuselage height h2 and the horizontal installation angle a1; of course, once x0 and L or x0, h1 and h2 are determined, a1 can also be determined.

[0130] The aforementioned internal parameters include the vertical field of view a2; the vertical field of view a2 is used to determine the maximum detection distance of the image acquisition device in the forward direction of the fuselage;

[0131] In other words, the first distance is determined based on the installation parameters of the image acquisition device, the internal parameters of the image acquisition device, and the preset height h3, wherein the preset height can be determined based on the height of grass or the height of obstacles in the working area;

[0132] In this disclosure, the preset height h3 is in the range of 0mm≤h3≤150mm;

[0133] In this disclosure, considering that the installation position of the image acquisition device cannot be too high to prevent shaking, and the installation position cannot be too low to prevent sewage, mud, dust and other contaminants from polluting the image acquisition device, in one embodiment, the installation height h1 of the image acquisition device is in the range of 150mm≤h1≤500mm.

[0134] Furthermore, considering that if the field of view of the image acquisition device is too large, the optical distortion of the image will increase, in one embodiment, the vertical field of view a2 of the image acquisition device is in the range of 45°≤a2≤90°.

[0135] Furthermore, considering that the automatic lawnmower operates outdoors and needs to be able to withstand harsh weather conditions such as strong winds, rain, and snow, in order to avoid the lens getting wet and affecting recognition, the rotation angle a3 of the image acquisition device is in the range of: 0≤a3≤75°.

[0136] Furthermore, considering that the installation distance of the image acquisition device cannot be too short, as it may capture too many images of the machine body, affecting recognition and increasing the risk of automatic lawnmower operation, thus reducing its safety; the installation distance also cannot be too long, as it may affect passability and prevent excessively large detection blind spots, in one embodiment, the installation distance X0 of the image acquisition device is in the range of 0≤x0≤220mm.

[0137] Furthermore, considering that the image acquisition device may be interfered with by strong light if the installation angle is too large, in one embodiment, the installation angle a1 is in the range of 0≤a1≤90°.

[0138] In one embodiment, when the reserved response distance is 600mm, in order to make the first distance greater than the above response distance, in this disclosure, the lower limit of the range of the installation height h1 is 160mm; the lower limit of the range of the installation distance x0 is -190mm (indicating that the camera can be installed 190mm behind the front of the camera body); the range of the horizontal installation angle a1 is 33°≤a1; the range of the vertical field of view a2 is 62°≤a2; and the range of the lens rotation angle a3 is 33°≤a3.

[0139] When the braking distance is 25mm and the image recognition distance is 300mm, the response distance is 325mm. In order to make the first distance greater than the above response distance, in this embodiment, the lower limit of the range of the installation height h1 must satisfy 85mm≤h1; the lower limit of the range of the installation distance x0 must satisfy -465mm≤x0; the lower limit of the range of the horizontal installation angle a1 must satisfy 18°≤a1; the lower limit of the range of the vertical field of view a2 must satisfy 34°≤a2; and the range of the lens rotation angle a3 must satisfy 18°≤a3.

[0140] It should be noted that with technological advancements, the braking distance or image recognition distance mentioned above will become smaller and smaller. In other words, the response distance can be smaller and smaller. Therefore, the acceptable range of the above four parameters will become wider and wider.

[0141] In one embodiment of this disclosure, the installation height h1 ranges from 218mm to 434mm; the installation distance x0 ranges from 0 to 83mm; the horizontal installation angle a1 ranges from 0° to 86°; the vertical field of view a2 ranges from 45° to 90°; and the lens rotation angle a3 ranges from 52° to 68°. Optionally, the installation height h1 = 220mm; the installation distance x0 = 17mm; the horizontal installation angle a1 = 38°; the lens rotation angle a3 = 53°; and the vertical field of view a2 = 73°.

[0142] By further limiting the range of the above parameters, the impact of tall grass on the image acquisition device during the automatic lawnmower's movement can be reduced. This allows the image acquisition device to acquire boundary images in a timely manner during movement, preventing the automatic lawnmower from failing to identify boundaries due to tall grass obstruction, thus avoiding collisions with physical boundaries or running out of the work area. In other words, based on the above parameter range, the image acquisition device can be reasonably set to ensure that the automatic lawnmower can effectively acquire surrounding images while moving, thereby ensuring the safety of the automatic lawnmower during operation.

[0143] In one embodiment of this disclosure, the installation height h1 ranges from 200mm ≤ h1 ≤ 400mm; the installation distance x0 ranges from 0 ≤ x0 ≤ 40mm; the horizontal installation angle a1 ranges from 30° ≤ a1 ≤ 45°; the vertical field of view a2 ranges from 60° ≤ a2 ≤ 80°; and the lens rotation angle a3 ranges from 30° ≤ a3 ≤ 45°. Optionally, the installation height h1 ranges from 220mm ≤ h1 ≤ 400mm; the installation distance x0 ranges from 17mm ≤ x0 ≤ 40mm; the horizontal installation angle a1 ranges from 38° ≤ a1 ≤ 45°; the vertical field of view a2 ranges from 73° ≤ a2 ≤ 80°; and the lens rotation angle a3 ranges from 30° ≤ a3 ≤ 45°. Optional installation height h1 = 220mm; installation distance x0 = 17mm; horizontal installation angle a1 = 38°; lens rotation angle a3 = 53°; vertical field of view a2 = 73°.

[0144] By further limiting the range of the above parameters, each parameter can fluctuate within its corresponding range, ensuring that the first distance is greater than the response distance (e.g., 325mm) while minimizing the second distance, thereby reducing the impact of blind spots on the image acquisition of the automatic lawnmower and improving the safety of the automatic lawnmower during operation.

[0145] Furthermore, the first distance is greater than or equal to 800mm. Optionally, the first distance can be 1000mm, 1250mm, 1500mm, 1600mm, 1750mm, 2000mm, or 2250mm. A larger first distance is more beneficial for the automatic lawnmower to detect the environment ahead and respond promptly. However, a larger first distance can also increase the blind spot, thus affecting the machine's ability to recognize the nearby environment. Therefore, by setting a reasonable first distance, both the blind spot range and timely detection of the environment ahead can be considered, better ensuring the safety of the automatic lawnmower's operation.

[0146] Furthermore, the response distance can range from 135mm to 1600mm, for example, it can be 135mm, 325mm, 500mm, 750mm, 1250mm, or 1600mm. Based on the factors affecting the response distance mentioned above, it is clear that with technological advancements, the response distance can become increasingly smaller.

[0147] In one embodiment, the internal parameters also include a horizontal field of view a4, which is used to determine the maximum detection distance of the image acquisition device in the width direction of the fuselage.

[0148] In one embodiment, the horizontal field of view a4 of the image acquisition device ranges from 60° to 160°.

[0149] In order to reduce the cost of the image acquisition device while taking into account its performance and technological maturity, in one embodiment, the ratio of the horizontal field of view a4 to the vertical field of view a2 of the image acquisition device is 4:3 or 16:9; in other words, the image acquisition device can be a camera with a lens aspect ratio of 4:3 or 16:9.

[0150] In this disclosure, the horizontal field of view a4 = 130° and the vertical field of view a2 = 73°.

[0151] Considering that the detection blind zone of the image acquisition device has a significant impact on the safety of the machine, in order to avoid the machine being unable to respond in time when facing boundary lines or obstacles due to the blind zone of the image acquisition device in the forward direction, resulting in the machine going out of bounds or colliding with obstacles, in one embodiment, a blind zone threshold can be used to represent the upper limit of the detection blind zone range of the image acquisition device. Thus, the second distance (used to represent the size of the detection blind zone) is less than or equal to the predetermined blind zone threshold.

[0152] In one embodiment, the distance between the second field of view boundary and the front end of the fuselage is less than or equal to 0; wherein the fuselage has a projection on a horizontal plane at a preset height, and the distance between the second field of view boundary and the front end of the fuselage is less than zero includes the second field of view boundary falling within the projection range of the projection of the fuselage onto the plane at the preset height.

[0153] In one embodiment, the field of view includes a first side and a second side defining its angular range along the fuselage's forward direction, the first side being away from the front end of the fuselage and the second side being close to the front end of the fuselage, wherein the second side is parallel to the tangent of the front end of the fuselage.

[0154] In one embodiment, the field of view includes a first side and a second side defining its angular range along the fuselage's forward direction, the first side being away from the front end of the fuselage and the second side being close to the front end of the fuselage, wherein the second side coincides with the tangent portion of the front end of the fuselage.

[0155] For ease of understanding, please refer to Figure 6 and Figure 8 When the preset height, such as grass height, h3 = 0, is used as an example, the image acquisition device projects onto the horizontal ground. At this time, the second field of view boundary BE (or BCE) falls into the projection range of the fuselage on the horizontal ground. In other words, the distance between the second field of view boundary BE (or BCE) and the front end of the fuselage is less than zero. This means that the second field of view boundary BE (or BCE) is located behind the projection point K of the front end of the fuselage 106 projected onto the horizontal ground (here, "behind" is with reference to the forward direction).

[0156] Reference Figure 11 The distance between the second field of view boundary BE (or BCE) and the front of the fuselage is a constant value greater than zero. The field of view (field of view area) has a first edge AD that is far from the front of the fuselage and pointing towards the horizontal ground along the direction of fuselage movement, and a second edge AC that is close to the front of the fuselage. The second edge AC is parallel to the tangent (the straight line passing through OK) of the front of the fuselage 106.

[0157] It is understandable that if point C coincides with point K, for example... Figure 4 and Figure 10 The distance between the second field-of-view boundary BE (or BCE) and the front of the fuselage is equal to 0. In one embodiment, referencing Figure 4 The field of view area along the direction of flight of the aircraft has a first edge AD that is far from the front of the aircraft and a second edge AC that is close to the front of the aircraft, wherein the second edge AC is tangent to the front of the aircraft 106 (e.g., Figure 4 The middle dashed line indicates or Figure 10 The lines passing through OK partially overlap.

[0158] In this disclosure, reference is made to Figures 2 to 10 The image acquisition device has internal parameters, including a vertical field of view. The field of view of the image acquisition device is projected onto a plane at a preset height. Along the direction of flight, the field of view has a first edge AD, pointing towards the grass, away from the front of the aircraft, and a second edge AC, pointing towards the front of the aircraft. The first edge AD and the second edge AC form a vertical field of view a2 (or ∠CAD). Figure 3 and Figure 4 As shown, the second edge AC coincides with the tangent at the front of the fuselage.

[0159] In other words, after the image acquisition device is installed, the second edge of the field of view in the forward direction of the machine is completely perpendicular or flush with the front of the machine, or the perpendicular line between the center point of the image acquisition device and the boundary of the second field of view is tangent to the front of the machine or at least partially coincides with the front of the machine, so that the image acquisition device has no detection blind spots in the forward direction and in the height direction perpendicular to the working area.

[0160] To avoid excessively large blind spots, in one embodiment, the preset blind spot threshold is 150mm.

[0161] Similarly, the distance between the second field of view boundary and the front of the fuselage is related to the installation parameters of the image acquisition device, the internal parameters of the image acquisition device itself, and the preset height.

[0162] In other words, the distance between the second field of view boundary and the front end of the fuselage is determined based on the installation parameters of the image acquisition device, the internal parameters of the image acquisition device, and the preset height h3;

[0163] The installation parameters include at least the installation height h1, the installation distance x0, and the installation angle, wherein the installation height h1 is the height of the image acquisition device above the horizontal ground; and the installation distance x0 is the horizontal distance of the image acquisition device from the front end of the fuselage.

[0164] The aforementioned installation angle includes the lens rotation angle a3, which is the angle between the central axis of the lens of the image acquisition device and the vertical direction.

[0165] Furthermore, the installation angle may also include a horizontal installation angle a1, which is the angle between the perpendicular line from the center axis of the lens of the image acquisition device and the horizontal line.

[0166] It is understandable that the installation distance x0 can be adjusted by adjusting the horizontal installation angle a1.

[0167] The aforementioned internal parameters include the vertical field of view a2; the vertical field of view a2 is used to determine the maximum detection distance of the image acquisition device in the forward direction of the fuselage;

[0168] The preset height can be determined based on the height of grass or obstacles in the working area; in one embodiment of this disclosure, the value range of the preset height h3 is 0mm≤h3≤150mm;

[0169] In this disclosure, to prevent shaking of the image acquisition device and contamination of the lens of the image acquisition device by splashing water, in one embodiment, the installation height h1 is in the range of 150mm≤h1≤500mm.

[0170] Furthermore, to prevent excessive optical distortion in the images acquired by the image acquisition device, in one embodiment, the vertical field of view a2 of the image acquisition device is in the range of 45°≤a2≤90°.

[0171] Furthermore, considering that the automatic lawnmower operates outdoors, in order to adapt the image acquisition device to rain and snow and prevent the lens from getting wet and affecting recognition, thus compromising safety, in one embodiment, the range of the lens rotation angle a3 is: 0≤a3≤75°.

[0172] Furthermore, in order to improve the passability of the image acquisition device and reduce the hazards of blind spots, in one embodiment, the installation distance X0 of the image acquisition device is in the range of 0≤x0≤220mm.

[0173] Furthermore, to avoid interference from strong light on the image acquisition device, in one embodiment, the installation angle a1 is set to a value of 0 ≤ a1 ≤ 90°.

[0174] In one embodiment of this disclosure, the installation height h1 is in the range of 200mm≤h1≤434mm; the installation distance x0 is in the range of 0≤x0≤83mm; the horizontal installation angle a1 is in the range of 0°≤a1≤107°; the vertical field of view a2 is in the range of 50°≤a2≤90°; and the lens rotation angle a3 is in the range of 30°≤a3≤68°.

[0175] By narrowing the parameters to the corresponding small range, regardless of how the parameters are selected within the corresponding small range, it satisfies the requirement that the first field of view boundary is greater than the braking distance and the image recognition distance (i.e., the first distance can adapt to any scenario with a response distance within 325mm), while also ensuring that the detection blind zone is not too large (the control blind zone does not exceed 150mm), which greatly improves the safety and passability of the automatic lawnmower and reduces the trouble for users.

[0176] In one embodiment, the internal parameters also include a horizontal field of view a4, which is used to determine the maximum detection distance of the image acquisition device in the width direction of the fuselage.

[0177] In one embodiment, the horizontal field of view a4 of the image acquisition device ranges from 60° to 160°.

[0178] In order to reduce the cost of the image acquisition device while taking into account its performance and technological maturity, in one embodiment, the ratio of the horizontal field of view a4 to the vertical field of view a2 of the image acquisition device is 4:3 or 16:9; in other words, the image acquisition device can be a camera with a lens aspect ratio of 4:3 or 16:9.

[0179] In one embodiment of this disclosure, the horizontal field of view a4 = 130° and the vertical field of view a2 = 73°.

[0180] Considering that the image acquisition device can identify target objects during the movement of the automatic lawnmower, especially stationary obstacles or dynamic obstacles with a speed less than a certain threshold, in one embodiment, the time taken for a target object within the field of view of the image acquisition device to appear and leave is not less than the image recognition time t1 of the automatic lawnmower.

[0181] In one embodiment, the time taken for a target to appear and disappear is determined by the following method:

[0182] The effective lateral distance within the field of view of the image acquisition device is determined by the walking speed v of the automatic lawnmower. The effective lateral distance refers to the detection distance of the image acquisition device minus the occlusion distance of obstructions; obstructions include the automatic lawnmower itself and / or the target object, where the target object includes boundary lines and obstacles.

[0183] For ease of understanding, please refer to the following: Figures 8 to 10 A brief description of the effective lateral distance within the field of view of the image acquisition device:

[0184] like Figure 8 As shown, the detection distance of the image acquisition device is DC. The occlusion distance of the obstruction includes the first distance DI obstructed by the grass height HI and the second distance KC obstructed by the automatic lawnmower itself. Therefore, it can be concluded that the effective lateral distance within the field of view of the image acquisition device is IK.

[0185] like Figure 9 As shown, the detection distance of the image acquisition device is DK. In fact, DK can also be understood as the detection distance minus the second distance blocked by the automatic lawnmower itself. The obstruction distance of the obstruction only includes the first distance DI blocked by the grass height HI. Therefore, it can be concluded that the effective lateral distance within the field of view of the image acquisition device is IK.

[0186] like Figure 10As shown, the detection range of the image acquisition device is DC, and the occlusion distance of the obstruction only includes the first distance DI obstructed by the grass height HI. Therefore, it can be concluded that the effective lateral distance within the field of view of the image acquisition device is IK.

[0187] To avoid problems such as the fuselage going out of bounds or colliding with obstacles during the turning process, in one embodiment, the field of view includes a third field of view boundary located to the left of the forward direction and a fourth field of view boundary located to the right of the forward direction along the direction perpendicular to the fuselage's forward direction;

[0188] The distance between the third and fourth field-of-view boundaries is 1.2-3 times the width of the automatic lawnmower. This helps to reduce or even eliminate blind spots in the width direction of the machine, and also avoids the problem of low image resolution affecting machine recognition.

[0189] In one embodiment, the width of the fuselage ranges from 400mm to 550mm.

[0190] In one embodiment, the distance between the third field of view boundary and the fourth field of view boundary is determined based on installation parameters, internal parameters of the image acquisition device, and a preset height h3; the installation parameters include at least the installation height h1; the internal parameters of the image acquisition device include a horizontal field of view a4; wherein the horizontal field of view a4 is configured to determine the detection distance of the image acquisition device along the width direction of the fuselage.

[0191] In one embodiment, the preset height h3 is in the range of 0mm≤h3≤150mm; the installation height h1 is in the range of 150mm≤h1≤500mm.

[0192] Furthermore, the horizontal field of view a4 of the image acquisition device has a range of 60°≤a4≤160°.

[0193] In one embodiment, the internal parameters of the image acquisition device further include a vertical field of view a2; the value range of the vertical field of view a2 of the image acquisition device is 48°≤a2≤90°.

[0194] In one embodiment, the ratio of the horizontal field of view a4 to the vertical field of view a2 is 4:3 or 16:9.

[0195] Furthermore, the horizontal field of view a4 = 130° and the vertical field of view a2 = 73°.

[0196] Considering that the field of view of the image acquisition device needs to completely cover the width of the vehicle body along the width direction, with a certain margin to eliminate blind spots, the margin cannot be too large, otherwise the effective image resolution will be too low, affecting recognition.

[0197] Of course, in other embodiments, the field of view coverage of the image acquisition device is projected onto a plane at a preset height. The field of view area along the direction of movement of the machine includes a third field of view boundary located on the left side of the direction of movement and a fourth field of view boundary located on the right side of the direction of movement; wherein the distance between the third field of view boundary or the fourth field of view boundary and the corresponding side of the machine body is not less than the turning radius of the automatic lawnmower.

[0198] To facilitate understanding, the field of view mentioned in the image acquisition device is briefly introduced below with reference to the accompanying drawings:

[0199] Reference Figure 2 The field of view of the image acquisition device shall include at least the cone-shaped area enclosed by points A, B, C, D, and E; wherein point A represents the center point of the image acquisition device, points B and E represent the farthest field of view positions along the width of the fuselage, and points C and D represent the farthest field of view boundary points along the length of the fuselage or the forward direction, respectively.

[0200] The aforementioned conical region can be, for example, a pyramidal region or a conical region. In one embodiment, the aforementioned conical region can be, for example, a square pyramidal region.

[0201] The image acquisition device has internal parameters, including the horizontal field of view (HFOV) and the vertical field of view (VFOV). In the figure, the horizontal field of view (HFOV) a4 = ∠BAE; the vertical field of view (VFOV) a2 = ∠CAD.

[0202] When the preset height h3 = 0, the field of view of the automatic lawnmower's image acquisition device is projected onto the horizontal ground. The field of view of the image acquisition device projected onto the horizontal ground is the area enclosed by points B, C, D, and E.

[0203] The field of view, projected onto the horizontal ground, has two sides along the direction of the aircraft's movement: one away from the front of the aircraft and one close to the front of the aircraft. These are represented by AD and AC in the figure, respectively. The angle ∠CAD between AD and AC is the vertical field of view of the image acquisition device.

[0204] It should be noted that the field of view projected by the image acquisition device onto the horizontal ground, along the direction of the fuselage's movement, has an edge (AC) that points towards the horizontal ground near the front of the fuselage, which may fall behind the front of the fuselage (e.g., Figure 9 ), obstructed by the fuselage, it may also land in front of the front of the fuselage (e.g. Figure 7 This results in a blind spot at the front of the fuselage.

[0205] To address the blind spot at the front of the automatic lawnmower when it travels on level ground, the distance between side AC and the front of the machine is equal to 0. Figure 10 As shown.

[0206] exist Figure 10 and Figure 11 In the process, a blind spot may still exist at the front of the fuselage in the height direction. When the preset height is greater than 0, it cannot respond in time to objects that suddenly appear near the front of the fuselage in the height h2 direction, which may easily lead to danger. In order to avoid the fuselage obstructing the field of view of image acquisition and to eliminate the blind spot at the front of the fuselage in the height h2 direction, in one embodiment, referring to Figure 4 When the image acquisition device cannot rotate, during installation, the installation angle a1 is adjusted so that AC at least partially coincides with the front end of the camera body or the tangent of AC at least partially coincides with the front end of the camera body. In another embodiment, if the image acquisition device can rotate, i.e., the image acquisition device has a lens rotation angle a3, during installation, the rotation angle a3 can be determined first from the angle of protection of the image acquisition device (e.g., protection against rain and snow), and then the installation angle a1 is adjusted so that AC at least partially coincides with the front end of the camera body or the tangent of AC at least partially coincides with the front end of the camera body.

[0207] In one embodiment, refer to Figure 3 , Figure 4 and Figure 5 The tangent of AC to the front of the fuselage at least partially coincides, eliminating blind spots at the front of the fuselage. In other words, AC is tangent to the front of the fuselage; at this point, AC is perpendicular to the horizontal ground, and the installation height of the image acquisition device is h1 = AC = d.

[0208] In this scenario, the field of view coverage projected onto the horizontal ground includes the field of view boundary BE near the front of the fuselage and the field of view boundary FG away from the front of the fuselage along the direction of the fuselage's movement. It can be understood that the field of view boundary BE is a line segment passing through point C, and the field of view boundary FG is a line segment passing through point D.

[0209] The field of view, projected onto the horizontal ground, is a trapezoidal area bounded by points B, E, F, and G. Figure 3 and Figure 5 The diagram schematically shows the fuselage width (represented by XY).

[0210] In one embodiment, refer to Figure 6 When the automatic lawnmower performs the mowing action in a working area with a preset height h3 greater than 0, Figure 6In the diagram, HI represents the preset height h3; the field of view coverage area projected onto the plane where the preset height h3 is greater than 0 can be the area enclosed by points P, M, H, and Q; where PM is parallel to BC; MQ is parallel to CE; HM is parallel to CD; and MC = HI.

[0211] It is understandable that when the preset height h3 = 0, the field of view coverage projected onto the horizontal ground can be the area enclosed by points B, C, D, and E.

[0212] In scenarios where the preset height h3 is greater than 0, the field of view coverage projected onto the plane with the preset height h3 greater than 0 includes a first field of view boundary away from the front of the fuselage and a second field of view boundary PQ closer to the front of the fuselage along the direction of fuselage movement. Although the first field of view boundary is not shown... Figure 6 However, it is understandable that the first field of view boundary lies on the plane at a height h3 above the horizontal ground that is greater than 0. Figure 7 The first field of view (the plane where HM is located) is a line segment passing through point H, and the first field of view is parallel to the field of view boundary FG projected onto the horizontal ground; the second field of view boundary PQ is a line segment passing through point M, and the second field of view boundary PQ is parallel to the field of view boundary BE projected onto the horizontal ground; the field of view coverage area projected onto the plane with a preset height h3 greater than 0 is a trapezoidal area enclosed by the four vertices of the first field of view boundary and the second field of view boundary PQ that pass through point H and are parallel to the field of view boundary FG projected onto the horizontal ground.

[0213] The installation of the image acquisition device is briefly described below:

[0214] In the direction of fuselage movement or in the direction of vertical field of view:

[0215] One of the constraints is that the distance between the object captured by the image acquisition device of the machine (short for automatic lawnmower) and the front of the machine body should be greater than the machine's response distance. This response distance is related to at least one of the braking distance, turning distance and image recognition distance. For example, it can be the braking distance or the turning distance or the braking distance + the turning distance, or it can be the sum of the braking distance (or the turning distance or the braking distance + the turning distance) and the image recognition distance.

[0216] Constraint 2: The blind zone of the machine's image acquisition device is less than or equal to the blind zone threshold. The blind zone threshold cannot be too large, so the blind zone threshold is preset to 500mm.

[0217] Constraint 3: The machine body should not appear within the near-end field of view boundary along the direction of flight of the image acquisition device, which is projected onto the horizontal ground or grass.

[0218] Considering that automatic lawnmowers have multiple components, in order to eliminate their adverse effects on the image acquisition device, the installation parameters of the image acquisition device are configured as the first parameter. This also ensures that the image acquisition device is not obstructed by other components of the automatic lawnmower, that is, to prevent other components from falling into the detection range of the image acquisition device.

[0219] Fourth constraint: The time required for the machine to recognize the image (image recognition time) should be less than or equal to the time from when the object appears at the far end of the field of view area projected onto the horizontal ground or a plane at a preset height within the field of view coverage of the image acquisition device (starting to capture the object image) to when the object leaves the near end of the field of view area projected onto the horizontal ground or a plane at a preset height within the field of view coverage of the image acquisition device (completing to capture the object image).

[0220] In the direction of fuselage width or horizontal field of view:

[0221] Fifth constraint: The horizontal field of view of the image acquisition device should cover a field of view range that does not collide with obstacles when turning.

[0222] For ease of understanding, the following is in conjunction with the appendix. Figure 7 To be continued Figure 11 A brief explanation of the factors to consider when installing an image acquisition device:

[0223] In the diagram, the image acquisition device is at a height of h1 (mm) above the ground; the automatic lawnmower is at a height of h2 (mm); the preset height (e.g., grass height or obstacle height) is h3 (mm); the automatic lawnmower's travel speed is v (mm / s); the image processing time of the image acquisition device is t1 (s); the machine braking time (time from normal travel to complete stop) is t2 (s); the installation angle of the image acquisition device is a1 (°); the vertical field of view of the image acquisition device is a2 (°); the lens rotation angle of the image acquisition device is a3 (°); the projection length CD of the vertical field of view boundary of the image acquisition device onto the horizontal ground is x1 (mm); the distance DK from the front end of the image acquisition device's far-end field of view boundary along the machine's forward direction onto the horizontal ground is x2 (mm); and the horizontal projection length HM of the grass height (or obstacle) within the field of view of the image acquisition device is... The width is x3 (mm); the horizontal projection of the grass height (or obstacle) within the field of view of the image acquisition device and the distance HN from the front of the machine body is x4 (mm); the braking distance during the automatic lawnmower's braking process is x5 (mm); the length of the cantilever used to install the image acquisition device is L (mm); the distance from the cantilever mounting point to the front of the machine body is k (mm), and the cantilever mounting point can be located on the front side or the rear side of the lawnmower. The front side refers to the side located in the forward direction of the lawnmower; the set distance is y (mm), and the set distance y is the lateral distance between the blade and the housing. The lateral direction refers to the horizontal direction perpendicular to the forward direction of the lawnmower; among them, the value range of the cantilever length L (OA) is: 0≤L; the value range of k is: 0≤k≤b, where b represents the width of the machine body; it can be understood that the value range of k indicates that the image acquisition device can be located at the front of the machine body and set backward).

[0224] When the automatic lawnmower is on a level surface, which can essentially be understood as a special scenario where the preset height, grass height, or obstacle height h3 = 0, for objects on a level surface:

[0225] x1=h1{tan(a2 / 2+a3)+tan(a2 / 2-a3)}

[0226] x2=h1tan(a2 / 2+a3)+Lcosa1-k

[0227] Where x0 = Lcosa1-k, x0 is the installation distance of the image acquisition device, representing the horizontal distance of the image acquisition device from the front end of the camera body (106). The installation constraints under the vertical field of view include at least one of the following:

[0228] Constraint A: The distance between the field of view boundary projected onto the horizontal ground and the front of the machine body is greater than or equal to the response distance of the automatic lawnmower. ；

[0229] A1 In any scenario where an automatic lawnmower encounters a boundary line or obstacle in front of it, and the automatic lawnmower uses braking to avoid going out of bounds or avoiding the obstacle:

[0230] A11 When the response distance is only related to the braking distance

[0231] x2=h1tan(a2 / 2+a3)+Lcosa1-k≥x5

[0232] When the response distance is related to both braking distance and image recognition distance, A12...

[0233] x2=h1tan(a2 / 2+a3)+Lcosa1-k≥t1v+x5

[0234] A13 When the response distance is related to the braking distance, image recognition distance, and set distance.

[0235] x2=h1tan(a2 / 2+a3)+Lcosa1-k≥t1v+x5-y

[0236] In one embodiment, the braking distance x5 is approximately equal to vt2; therefore, when the response distance is only related to the braking distance,

[0237] x2 / v=h1{tan(a2 / (2+a3))+Lcosa1-k} / v≥t2

[0238] In one embodiment, the image acquisition device is installed at the front of the device, in which case k = 0.

[0239] In one embodiment, the installation distance x0 of the image acquisition device ranges from 0 to 220 mm.

[0240] A2 When a boundary line or obstacle appears in front of the automatic lawnmower, if the automatic lawnmower uses a turning method to avoid going out of bounds or to turn to walk along the edge or avoid obstacles in any scenario, the turning distance, such as the turning radius r, can be used to replace x5 in the above formula to obtain the installation constraint under the vertical field of view in the turning scenario. To save space, this embodiment will not elaborate further.

[0241] Constraint C: The time taken for a target on the horizontal ground to appear and leave is not less than the image recognition time t1 of the automatic lawnmower; the target can be an obstacle, especially a static obstacle such as a branch or a stone, or a boundary line or other object.

[0242] Expressed as a formula:

[0243]

[0244] In one embodiment, when the installation height h1 of the image acquisition device is greater than or equal to the machine's own height h2...

[0245] x2=h1tan(a2 / 2+a3)+Lcosa1-k

[0246] It can be transformed into:

[0247]

[0248] In one embodiment, the fuselage height h2 ranges from 190mm to 220mm;

[0249] In one embodiment, when the near-end field-of-view boundary (e.g., the second edge AC of the vertical field of view) of the image acquisition device is tangent to or at least partially coincides with the front end of the fuselage, then x1 = x2; therefore,

[0250]

[0251] Furthermore, we can obtain:

[0252]

[0253] Similarly, when an automatic lawnmower is on a lawn at a preset height h3, for objects on a plane at the preset height:

[0254] x3=(h1-h3){tan(a2 / 2+a3)+tan(a2 / 2-a3)}

[0255] x4=(h1-h3)tan(a2 / 2+a3)+Lcosa1-k

[0256] Where, x0 = Lcosa1-k.

[0257] The installation constraints under the vertical field of view must include at least one of the following:

[0258] Constraint Q: The distance between the field of view boundary (i.e., the first field of view boundary) projected onto the plane at a preset height and the front end of the machine body is greater than or equal to the response distance of the automatic lawnmower. ；

[0259] Q1. In scenarios where an automatic lawnmower encounters or detects a boundary line or obstacle in front of it, and the automatic lawnmower steers to avoid going out of bounds or to travel along the edge:

[0260] Q11 When the response distance is only related to the braking distance

[0261] x4=(h1-h3)tan(a2 / 2+a3)+Lcosa1-k≥x5

[0262] Q12 When the response distance is related to the braking distance and the image recognition distance...

[0263] x4=(h1-h3)tan(a2 / 2+a3)+Lcosa1-k≥t1v+x5

[0264] Q13 When the response distance is related to the braking distance, image recognition distance, and set distance...

[0265] x4=(h1-h3)tan(a2 / 2+a3)+Lcosa1-k≥t1v+x5-y

[0266] In one embodiment, the aforementioned braking distance x5 is approximately equal to v t2.

[0267] Q2 When a boundary line or obstacle appears in front of the automatic lawnmower, if the automatic lawnmower uses a turning method to avoid going out of bounds or to turn to walk along the edge, the turning distance, such as the turning radius r, can be used to replace x5 in the above formula to obtain the installation constraint under the vertical field of view in the turning scenario. To save space, this embodiment will not elaborate further.

[0268] Constraint P: The image recognition time t1 of the automatic lawnmower is less than or equal to the time taken for a target object on a plane of preset height to appear and leave. ； In other words, the time from when the target appears at the first field of view boundary (when the camera is ready to capture the image of the object) to when the target leaves the second field of view boundary (when the camera has completed capturing the image of the object) should be greater than or equal to the time required for the machine to recognize the image; the aforementioned target can be, for example, an obstacle, especially a static obstacle such as a tree branch or a rock, or a boundary line or other object;

[0269] Expressed as a formula:

[0270]

[0271] In one embodiment, if the image acquisition device is mounted on the camera body and cannot rotate around its own lens optical axis, the following applies... Figures 7 to 11 A brief explanation of the factors to consider when installing an image acquisition device:

[0272] In the diagram, the horizontal distance between the image acquisition device and the front of the machine body is x0 (mm); the preset height, grass height, or obstacle height is h3 (mm); the automatic lawnmower's travel speed is v (mm / s); the image processing time of the image acquisition device is t1 (s); the machine braking time (time from normal travel to complete stop) is t2 (s); the installation angle of the image acquisition device is a1 (°); the vertical field of view of the image acquisition device is a2 (°); and the length of the projection CD of the vertical field of view boundary of the image acquisition device onto the horizontal ground is... x1 (mm); the distance DK between the projection of the far-end field of view boundary of the image acquisition device along the forward direction of the machine and the front end of the machine is x2 (mm); the horizontal projection HM of the grass height (or obstacle) within the field of view of the image acquisition device is x3 (mm); the distance HN between the horizontal projection of the grass height (or obstacle) within the field of view of the image acquisition device and the front end of the machine is x4 (mm); the braking distance during the braking process of the automatic lawnmower is x5 (mm); the height of the automatic lawnmower is h2 (mm);

[0273] When the automatic lawnmower is on a level surface, the situation can be understood as a special scenario where the preset height, grass height, or obstacle height h3 = 0:

[0274] x1=h1{tan(a2 / 2+a3)+tan(a2 / 2-a3)}

[0275] x2=h1tan(a2 / 2+a3)+x0

[0276] The installation constraints under the vertical field of view should satisfy at least one of the following constraints:

[0277] Constraint 1: The distance between the edge of the field of view projected onto the horizontal ground and the front of the machine body is greater than or equal to the response distance of the automatic lawnmower;

[0278] For simplicity, this description assumes an automatic lawnmower braking to avoid going out of bounds or over obstacles when a boundary line or obstacle appears in front of it, and that the response distance is only related to the braking distance.

[0279] x2=h1tan(a2 / 2+a3)+x0≥x5

[0280] Since the braking distance x5 is related to the braking time t2 and the driving speed v, in one embodiment, the braking distance x5 is approximately equal to vt2; in any scenario where a boundary line or obstacle appears in front of the automatic lawnmower, and the automatic lawnmower uses braking to avoid going out of bounds or avoiding obstacles, and when the response distance is only related to the braking distance, x2 = h1tan(a2 / 2+a3)+x0, we can obtain:

[0281] x2 / v=(h1tan(a2 / 2+a3)+x0) / v≥t2

[0282] Constraint 2: The time taken for a target on the horizontal ground to appear and leave is not less than the image recognition time t1 of the automatic lawnmower; the target can be an obstacle, especially a static obstacle such as a branch or a stone, or a boundary line or other object.

[0283] Expressed as a formula:

[0284] x1 / v=h1{tan(a2 / 2)+a3+tan(a2 / 2-a3)} / v≥t1

[0285] Constraint 3: The distance between the second field of view boundary and the front of the fuselage is less than or equal to the preset blind zone distance, and the machine body does not appear in the field of view.

[0286] Considering that blind spots can affect machine safety, they should not be too large. In this embodiment, when the preset height is 0, the preset blind spot distance is 150mm. The constraint to be satisfied at this time is expressed by the following formula:

[0287] 0≤h2-h1tan(a2 / 2-a1)≤150

[0288] In this disclosure, the boundary conditions are as follows:

[0289] 0°≤a3≤90°

[0290] 0°≤a1≤180°

[0291] 0 < h2 ≤ h1

[0292] The image acquisition device should not be installed too high to prevent shaking; nor should it be installed too low to prevent sewage, mud, dust, etc., from contaminating the image acquisition device. In this disclosure, the installation height of the image acquisition device should meet the following constraints:

[0293] 200mm≤h1≤500mm

[0294] If the field of view of the image acquisition device is too large, the optical distortion of the image will increase. Therefore, in this disclosure,

[0295] 45°≤a2≤90°

[0296] Similarly, when an automatic lawnmower is on a lawn with grass height, for objects on a plane with a preset height h3 greater than 0:

[0297] x3=(h1-h3){tan(a2 / 2+a3)+tan(a2 / 2-a3)}

[0298] x4=(h1-h3)tan(a2 / 2+a3)+x0

[0299] The constraints to be satisfied in this disclosure are as follows:

[0300] x4=(h1-h3)tan(a2 / 2+a3)+x0≥x5

[0301]

[0302] x3 / v=(h1-h3){tan(a2 / 2+a3)+tan(a2 / 2-a3)} / v≥t1

[0303] 0≤h2-(h1-h3)tan(a2 / 2-a3)≤50mm

[0304] 0≤a1≤180°

[0305] 0≤a3≤90°

[0306] 0 < h2 ≤ h1;

[0307] 45°≤a2≤90°

[0308] 200mm≤h1≤500mm

[0309] 0≤h3≤150mm

[0310] In this disclosure, to ensure the machine's compact, simple, and aesthetically pleasing structure, as well as its safety performance (blind spot), the rationality of the selected field of view and installation angle of the image acquisition device is verified. For example, in the length direction, there must be at least a 2-second distance between the vehicle body and the farthest point of the field of view to ensure safety and avoid an excessively large blind spot. In the width direction, the width of the vehicle body needs to be completely covered, with a certain margin (0.5 times the machine width) to eliminate blind spots, but the margin cannot be too large, otherwise the effective image resolution will be too low, affecting recognition. The further defined range is as follows:

[0311] 200mm≤h1≤423mm

[0312] 0°≤a1≤107°

[0313] 30°≤a3≤68°

[0314] 50°≤a2≤90°

[0315] 0≤x0≤83mm

[0316] In another embodiment, for safety reasons, when the machine reaches the edge of the grassland, if there is an obstacle higher than the grassland (such as a wall, fence, etc.), the camera should capture the obstacle within its field of view, and the view should not be completely obscured by vegetation. If, at a distance b / 2 from the center of the camera's field of view in the width direction (b is the width of the machine), the camera cannot detect the space higher than the vegetation and directly assumes the machine is safe, the machine will continue to move towards the obstacle, resulting in a collision.

[0317] Therefore, constraint six can be determined based on the extreme case. Constraint six (or the extreme case) is that the obstacle is close to the side of the machine, that is, at a distance b / 2 from the center of the camera's field of view in the width direction, the obstacle higher than the vegetation is just detected in the camera's field of view. Conversely, the greater the distance from the center of the machine to the obstacle higher than the vegetation detected by the camera's field of view, the higher the machine's safety attribute. That is, at a distance b / 2 from the center of the camera's field of view in the width direction, the height that can be detected in the camera's field of view should be greater than or equal to the height h3 of the vegetation.

[0318] The following is combined Figure 6 , Figure 7 , Figure 15 and Figure 16 The lateral constraints are explained below. The camera's field of view is an irregular ellipsoid, which can be approximated as a triangle for simplified calculations. Therefore, in... Figure 7 middle exist Figure 6 middle

[0319] Figure 15 This diagram illustrates the positional relationship between the camera's field of view projected onto the horizontal plane and the lawnmower's body projected onto the horizontal plane. In the diagram, UV and DC are parallel, UV is collinear with the side of the lawnmower's body, and the distance between UV and DC is half the width of the lawnmower (b / 2).

[0320] Figure 16 This diagram illustrates the camera's field of view along the direction of BC. Due to vegetation obstruction, the camera's field of view corresponding to the dashed line cannot detect obstacles. Therefore, the height of the field of view at Z' must be greater than or equal to the height of the vegetation to detect obstacles near Z', thereby reducing the probability of collision between the machine and obstacles. Analysis shows that, at a distance b / 2 from the center of the camera's field of view in the width direction, the constraints to avoid collisions between the machine and obstacles include: at a distance b / 2 from the center of the camera's field of view in the width direction, the height that the camera can detect is h4 ≥ the height of the vegetation h3.

[0321] Based on similar triangles, we can obtain:

[0322]

[0323]

[0324] Then h4≥h3 means:

[0325]

[0326] Therefore, the scope is further defined as follows:

[0327] The installation height h1 ranges from 218mm to 434mm; the installation distance x0 ranges from 0 to 83mm; the horizontal installation angle a1 ranges from 0° to 86°; the vertical field of view a2 ranges from 45° to 90°; and the lens rotation angle a3 ranges from 52° to 68°.

[0328] In this disclosure, based on actual operating conditions, the final installation parameters and internal parameters of the image acquisition device are determined as follows: h1 = 220 mm, a2 = 73 degrees, a1 = 38 degrees, a1 = 53 degrees, a4 = 130 degrees, x0 = 17 mm.

[0329] When the image acquisition device is installed according to the above parameters (220mm, 17mm, 38 degrees, 53 degrees, 73 degrees), the distance between the first field of view boundary and the front end of the body is 1600mm.

[0330] In one embodiment, if the image acquisition device is mounted on the camera body and cannot rotate around its own lens optical axis, such as Figure 12 As shown, when the image acquisition device is installed, its centerline is perpendicular to the mounting plane. Therefore, it can be known that the lens rotation angle a3 of the image acquisition device is equal to the installation angle a1 of the image acquisition device, i.e., a3 = a1. The following is combined with... Figures 12 to 14 A brief explanation of the factors to consider when installing an image acquisition device:

[0331] When the automatic lawnmower is on a level surface, the situation can be understood as a special scenario where the preset height, grass height, or obstacle height h3 = 0:

[0332] x1=h1{tan(a2 / 2+a1)+tan(a2 / 2-a1)}

[0333] x2=h1tan(a2 / 2+a1)+x0

[0334] x2=h1tan(a2 / 2+a3)+x0≥x5

[0335] x2 / v=(h1tan(a2 / 2+a1)+x0) / v≥t2

[0336] x1 / v=h1{tan(a2 / 2)+a1+tan(a2 / 2-a1)} / v≥t1

[0337] 0≤h2-h1tan(a2 / 2-a1)≤50mm

[0338] In this disclosure, since the influence of light on the image acquisition device during use should be avoided, direct light entering the field of view of the image acquisition device should be prevented. Therefore, as Figure 13 As shown: When the field of view of the image acquisition device is within the angular range of the first edge (also known as the left boundary) AD and the second edge (also known as the right boundary) AC along the direction of the aircraft's movement, the critical state is when the left boundary AD is horizontal. At this time, a3 + a2 / 2 ≤ 90°, and a3 = a1. Therefore, the boundary condition that must be satisfied is:

[0339] a1 + a2 / 2 ≤ 90°

[0340] Because image acquisition devices should achieve the widest possible field of view during use to improve machine safety, therefore, such as Figure 14 As shown: The critical state is when the center line of the field of view of the image acquisition device is perpendicular to the horizontal plane. At this time, a3 = a1 = 0°, so the boundary conditions are:

[0341] 0°≤a1

[0342] Other constraints are:

[0343] 200mm≤h1≤500mm

[0344] 45°≤a2≤90°

[0345] Similarly, when an automatic lawnmower is on a lawn with grass height, for objects on a plane with a preset height h3 greater than 0:

[0346] x3=(h1-h3){tan(a2 / 2+a1)+tan(a2 / 2-a1)}

[0347] x4=(h1-h3)tan(a2 / 2+a1)+x0

[0348] The constraints to be satisfied in this disclosure are as follows:

[0349] x4=(h1-h3)tann(a2 / 2+a1)+x0≥x5

[0350]

[0351] x3 / v=(h1-h3){tan(a2 / (2+a1))+tan(a2 / 2-a1)} / v≥t1

[0352] 0≤h2-(h1-h3)tan(a2 / 2-a1)≤50mm

[0353] a1 + a2 / 2 ≤ 90°

[0354] 0≤a1

[0355] 45°≤a2≤90°

[0356] 200mm≤h1≤500mm

[0357] 0≤h3≤150mm

[0358] In this disclosure, to ensure the machine's compact, simple, and aesthetically pleasing structure, as well as its safety performance (blind spot), the rationality of the selected field of view and installation angle of the image acquisition device is verified. For example, in the length direction, there must be at least a 2-second distance between the vehicle body and the farthest point of the field of view to ensure safety and avoid an excessively large blind spot. In the width direction, the width of the vehicle body needs to be completely covered, with a certain margin (0.5 times the machine width) to eliminate blind spots, but the margin cannot be too large, otherwise the effective image resolution will be too low, affecting recognition. The further defined range is as follows:

[0359] 200≤h1≤400

[0360] 30°≤a1≤45°

[0361] 30°≤a3≤45°

[0362] 60°≤a2≤80°

[0363] 0≤x0≤40mm

[0364] In this disclosure, based on actual operating conditions, the final installation parameters and internal parameters of the image acquisition device are determined as follows: h1 = 220 mm, a2 = 73 degrees, a1 = a3 = 38 degrees, a4 = 130 degrees, x0 = 17 mm.

[0365] When the image acquisition device is installed according to the above parameters (220mm, 17mm, 38 degrees, 73 degrees), the distance between the first field of view boundary and the front end of the body is 808mm.

[0366] In one embodiment, the horizontal field of view of the image acquisition device should cover a range that allows it to turn without touching obstacles; for example, constraints in the width direction of the fuselage include:

[0367] Constraint B: The horizontal field of view of the image acquisition device should meet the requirement that it does not touch the boundary line or obstacles when turning, or that the distance from the boundary line or obstacles during the turning process is within the error range;

[0368] The field of view of the B1 image acquisition device is projected onto a plane at a preset height. The field of view area along the direction of flight includes a third field of view boundary on the left side of the direction of flight and a fourth field of view boundary on the right side of the direction of flight.

[0369] Among them, the distance between the third or fourth field of view boundary and the corresponding side of the machine body is not less than the turning radius of the automatic lawnmower.

[0370] Reference Figure 3 and Figure 5 When the automatic lawnmower is on a horizontal surface, the installation height of the image acquisition device is h1 (mm), and the horizontal field of view of the image acquisition device is a4 (°). The projection distance between the centerline of the image acquisition device and the boundary of the horizontal field of view on the horizontal surface is x6 (mm). The turning radius of the machine is r (mm). The width of the machine (XY) is b (mm). The constraints under the horizontal field of view can be determined as follows:

[0371] x6-b / 2≥r

[0372] x6 = h1 tan(a4 / 2)

[0373] From the above, we can conclude that:

[0374] h1tan(a4 / 2)-b / 2≥r

[0375] Furthermore, it can be obtained that when the automatic lawnmower is on a plane with a preset height of h3 within the working area, the constraint under the horizontal field of view is:

[0376] (h1-h3)tan(a4 / 2)-r≥b / 2

[0377] The field of view of the B2 image acquisition device is projected onto a horizontal ground at a preset height h3 of 0. The field of view area includes a field of view boundary on the left side of the forward direction and a field of view boundary on the right side of the forward direction. The distance between the two field of view boundaries is 1.8-2.2 times the width of the automatic lawnmower.

[0378] The field of view of the B3 image acquisition device is projected onto a plane with a preset height (e.g., grass height) h3 greater than 0, for example, h3 = 150 mm. The field of view includes a third field of view boundary on the left side of the forward direction and a fourth field of view boundary on the right side of the forward direction. The distance between the third and fourth field of view boundaries is 1.6-2 times the width of the automatic lawnmower.

[0379] This can be expressed by the formula: 1.6b≤2(h1-h3)tan(a4 / 2)≤2b

[0380] Furthermore, the image acquisition device can be, for example, a depth camera, mounted on the machine body and configured to acquire images in the direction the machine is moving forward;

[0381] Furthermore, the depth camera is also configured to identify obstacles in the image; that is, to determine the type of obstacle when it appears in the image.

[0382] The obstacles here can be static or dynamic objects. The types of obstacles include, but are not limited to, inanimate objects such as stones and trees, as well as living objects such as animals or people.

[0383] Depth cameras rely on visual AI (Artificial Intelligence) to identify obstacles. In one approach, the depth camera can identify obstacles based on supervised learning deep learning algorithms, such as identifying the type of obstacle based on a pre-trained convolutional neural network model. It is understood that depth cameras can also identify obstacles based on other machine learning or deep learning algorithms, and this embodiment does not specifically limit this.

[0384] Furthermore, depth cameras can be monocular cameras, binocular cameras, or trinocular stereo cameras;

[0385] In one alternative implementation, the depth camera employs a trinocular stereo camera to achieve stereo recognition of obstacles.

[0386] Furthermore, the depth camera is mounted on the top front or the top front of the machine body;

[0387] Furthermore, the depth camera is embedded in an externally mounted impact-resistant housing (e.g., a cantilever) to prevent damage from impacts.

[0388] In this embodiment, the depth camera is installed at a height of 220mm, mounted on the top of the machine body, facing downwards, with a horizontal installation angle of 38°, a lens rotation angle of 53°, a vertical field of view of 73°, and a horizontal field of view of 130°.

[0389] In another embodiment, the depth camera is mounted at a height of 220mm, on the top of the machine body, facing downwards, meaning that the lens rotation angle and the horizontal mounting angle are equal and both are 38°. The vertical field of view of the depth camera is set to 73°, and the horizontal field of view is set to 130°.

[0390] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

[0391] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. An automatic lawnmower, characterized in that... The automatic lawnmower is capable of moving autonomously and performing lawnmowing tasks within a preset working area, including: The body has a front end and a rear end relative to each other along the forward direction of the automatic lawnmower; The moving module drives the automatic lawnmower to move; The lawn mowing component cuts the grass within the working area; An image acquisition device is installed at the top front end of the fuselage to acquire images in the forward direction of the fuselage; in, The area covered by the field of view of the image acquisition device projected onto a horizontal plane at a preset height is the field of view area of ​​the image acquisition device. The field of view area along the forward direction of the automatic lawnmower includes a first field of view boundary away from the front end of the machine body and a second field of view boundary close to the front end of the machine body; the field of view area along the direction perpendicular to the forward direction of the machine body includes a third field of view boundary located to the left of the forward direction and a fourth field of view boundary located to the right of the forward direction; wherein, the distance between the third field of view boundary and the fourth field of view boundary is 1.2 to 3 times the width of the automatic lawnmower body; in, The image acquisition device is configured to be installed according to preset installation parameters, such that the first field of view boundary is a first distance from the front end of the fuselage, and the second field of view boundary is a second distance from the front end of the fuselage; the first distance, the second distance, and the distance between the third field of view boundary and the fourth field of view boundary are determined based on the installation parameters of the image acquisition device, the internal parameters of the image acquisition device, and a preset height h3, wherein the preset height h3 has a value range of 0mm≤h3≤150mm; in, The first distance is greater than or equal to the response distance of the automatic lawnmower, the response distance being the distance required for the automatic lawnmower to avoid a target object, which includes boundaries and obstacles; and, The second distance is less than or equal to 500mm.

2. The automatic lawnmower according to claim 1, characterized in that, The response distance includes at least one of braking distance and image recognition distance; Wherein, the braking distance is the distance the automatic lawnmower travels to avoid the target object by braking; the image acquisition device has an image recognition time, and the image recognition distance is the distance the automatic lawnmower travels within the image recognition time.

3. The automatic lawnmower according to claim 2, characterized in that, The first distance is greater than or equal to the sum of the braking distance of the automatic lawnmower and the image recognition distance; The braking distance is related to at least one of the following motion parameters of the automatic lawnmower: braking time and the driving speed of the automatic lawnmower; the image recognition distance is related to the image recognition time of the image acquisition device and the driving speed of the automatic lawnmower.

4. The automatic lawnmower according to claim 3, characterized in that, The driving speed ranges from 0.25 m / s to 0.5 m / s; The braking time ranges from 50ms to 2s; The braking distance ranges from 12.5mm to 1000mm; The image recognition time ranges from 50ms to 500ms, and the image recognition distance ranges from 125mm to 250mm.

5. The automatic lawnmower according to claim 1, characterized in that, The installation parameters include at least the installation height h1, the installation distance x0, and the installation angle, wherein the installation height h1 is the height of the image acquisition device above the horizontal ground; the installation distance x0 is the horizontal distance of the image acquisition device from the front end of the body; and the installation angle includes the lens rotation angle a3, which is the angle between the central axis of the lens of the image acquisition device and the vertical direction. The internal parameters of the image acquisition device include the vertical field of view a2.

6. The automatic lawnmower according to claim 1, characterized in that, The second distance is less than or equal to a predetermined blind zone threshold.

7. The automatic lawnmower according to claim 5, characterized in that, The value range of the installation height h1 is: 150mm≤h1≤500mm.

8. The automatic lawnmower according to claim 7, characterized in that, The vertical field of view angle a2 is in the range of 45°≤a2≤90°.

9. The automatic lawnmower according to claim 7, characterized in that, The range of the lens rotation angle a3 is 0 ≤ a3 ≤ 75°.

10. The automatic lawnmower according to claim 7, characterized in that, The installation distance x0 is in the range of 0 ≤ x0 ≤ 220 mm.

11. The automatic lawnmower according to claim 7, characterized in that, The installation angle also includes a horizontal installation angle a1, which is the angle between the perpendicular line to the central axis of the lens of the image acquisition device and the horizontal line. The value range of the installation height h1 is 218mm≤h1≤434mm; The installation distance x0 is in the range of 0 ≤ x0 ≤ 83 mm; The range of the horizontal installation angle a1 is 0°≤a1≤86°; The vertical field of view angle a2 is in the range of 45°≤a2≤90°; The range of the lens rotation angle a3 is 52°≤a3≤68°.

12. The automatic lawnmower according to claim 7, characterized in that, The installation angle also includes a horizontal installation angle a1, which is the angle between the perpendicular line to the central axis of the lens of the image acquisition device and the horizontal line. The value range of the installation height h1 is 200mm≤h1≤400mm; The installation distance x0 is in the range of 0 ≤ x0 ≤ 40 mm; The range of the horizontal installation angle a1 is 30°≤a1≤45°; The vertical field of view angle a2 is in the range of 60°≤a2≤80°; The range of the lens rotation angle a3 is 30°≤a3≤45°.

13. The automatic lawnmower according to claim 7, characterized in that, The response distance ranges from 135mm to 1250mm.

14. The automatic lawnmower according to claim 7, characterized in that, The first distance is greater than or equal to 800mm.

15. The automatic lawnmower according to claim 7, characterized in that, The second distance is less than or equal to 0, wherein the fuselage has a projection on a horizontal plane at a preset height, and the second distance being less than zero includes the second field of view boundary being within the projection range.

16. The automatic lawnmower according to claim 6, characterized in that, The blind zone threshold ranges from 50mm to 500mm.

17. The automatic lawnmower according to any one of claims 5 to 16, characterized in that, The internal parameters of the image acquisition device also include a horizontal field of view a4, the value of which is 60°≤a4≤160°; or, the internal parameters of the image acquisition device also include a horizontal field of view a4, the ratio of which is 4:3 or 16:9 to the vertical field of view a2.

18. The automatic lawnmower according to claim 1, characterized in that, The range of the fuselage width is 400mm to 550mm.

19. The automatic lawnmower according to claim 1, characterized in that, The distance between the third field of view boundary and the fourth field of view boundary is determined based on the installation parameters, the internal parameters of the image acquisition device, and the preset height h3. in, The installation parameters include at least the installation height h1; the internal parameters of the image acquisition device include the horizontal field of view a4; wherein the horizontal field of view a4 is configured to determine the detection distance of the image acquisition device along the width of the fuselage.

20. The automatic lawnmower according to claim 19, characterized in that, The value range of the installation height h1 is 150mm≤h1≤500mm; The preset height h3 has a value range of 0mm≤h3≤150mm; The horizontal field of view a4 of the image acquisition device has a range of 60°≤a4≤160°.

21. The automatic lawnmower according to claim 19, characterized in that, The internal parameters of the image acquisition device also include the vertical field of view a2; the value range of the vertical field of view a2 of the image acquisition device is 45°≤a2≤90°; or, the ratio of the horizontal field of view a4 to the vertical field of view a2 is 4:3 or 16:9.

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