Forklift anti-falling method and system based on dock edge recognition

Abstract

The invention discloses a forklift anti-falling method and system based on dock edge recognition. The method comprises the steps that the installation angle of a first distance measuring sensor installed on the rear portion of a forklift is obtained; acquiring a first fixed ranging distance based on the installation angle of the first ranging sensor; if the actual measurement distance of the first distance measuring sensor exceeds the first fixed distance measuring distance, the forklift is controlled to run at a first preset speed in a limited speed mode; the installation angle of a second distance measuring sensor installed on the rear portion of the forklift is obtained; acquiring a second fixed ranging distance based on the installation angle of the second ranging sensor; if the actual measurement distance of the second distance measuring sensor exceeds the second fixed distance measuring distance, the forklift is controlled to run at a second preset speed in a limited speed mode; a projection image collected by an image sensor installed behind the forklift is obtained; and whether the projection shape above the platform step changes is judged, and if yes, the forklift is controlled to stop running. Automatic speed limiting of the forklift in the designated area can be achieved, and the safety of the forklift is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle safety, and particularly to a forklift anti-fall method and system based on platform edge recognition. Background Art

[0002] When a forklift loads / unloads goods, it needs to drive to the edge of the platform. When the driving speed of the forklift is too fast or the driver misjudges the edge of the platform, it is easy to cause a forklift fall accident on the platform, and in severe cases, it will cause a major accident of vehicle damage and death.

[0003] The comparative document "Forklift anti-fall platform automatic warning device and its alarm method, 201910796609.7" discloses an automatic warning device including an alarm main controller arranged in the forklift cockpit, four anti-fall ranging sensors respectively fixed on each column of the forklift overhead guard, a collision avoidance ranging sensor fixed on the top of the forklift overhead guard with its probe facing the rear lower part of the forklift, and a false alarm prevention ranging sensor fixed on the top of the forklift overhead guard with its probe vertically facing directly above the forklift. Among them, the anti-fall ranging sensor monitors the distance between the forklift and the edge of the platform, and when the real-time ranging value exceeds the set threshold, it automatically alarms to remind the forklift driver to immediately turn or stop running to avoid accidents. However, on the one hand, the anti-fall ranging sensor in the comparative document can only make one judgment and cannot make judgments in different regions, unable to meet the requirements of stage control. On the other hand, the comparative document only uses the ranging sensor to achieve the warning function and cannot achieve the automatic braking function, with poor safety, and the vehicle speed can only be controlled by the driver himself. Summary of the Invention

[0004] The main object of the present invention is to overcome the above defects in the prior art, and propose a forklift anti-fall method and system based on platform edge recognition. By using two ranging sensors and an image sensor installed in different positions to detect the edge of the platform respectively, when the corresponding sensor detects the edge of the platform, corresponding regional speed control is performed to achieve stable deceleration of the forklift while improving the safety of the forklift.

[0005] The present invention adopts the following technical solutions:

[0006] On the one hand, a forklift anti-fall method based on platform edge recognition includes:

[0007] Obtain the installation angle of the first ranging sensor installed behind the forklift;

[0008] Based on the installation angle of the first ranging sensor, obtain the first fixed ranging distance of the first ranging sensor above the platform step;

[0009] Determine whether the actual measured distance of the first distance measuring sensor exceeds the first fixed distance measuring distance. If it exceeds, control the forklift to travel at a limited speed of the first preset speed; otherwise, control the forklift to travel at a normal speed;

[0010] Obtain the installation angle of the second distance measuring sensor installed at the rear of the forklift;

[0011] Based on the installation angle of the second distance measuring sensor, obtain the second fixed distance measuring distance of the second distance measuring sensor above the platform steps;

[0012] Determine whether the actual measured distance of the second distance measuring sensor exceeds the second fixed distance measuring distance. If it exceeds, control the forklift to travel at a limited speed of the second preset speed; otherwise, control the forklift to travel at the first preset speed;

[0013] Obtain the projected image collected by the image sensor installed at the rear of the forklift; the projected image is projected by the projection device installed at the rear of the forklift;

[0014] Determine whether the projection shape above the platform steps has changed. If so, control the forklift to stop running; otherwise, control the forklift to travel at the second preset speed.

[0015] Preferably, the installation angle of the first distance measuring sensor is calculated based on the set lengths of the first deceleration area, the second deceleration area, the parking area, and the installation height of the first distance measuring sensor, or the installation angle of the first distance measuring sensor is obtained by acquiring a first preset installation angle, and the first preset installation angle is calculated based on the set lengths of the first deceleration area, the second deceleration area, the parking area, and the installation height of the first distance measuring sensor.

[0016] Preferably, the calculation method of the installation angle of the first distance measuring sensor is as follows:

[0017] Θ1 = arctan((L1 + L2 + L3) / H1)

[0018] Wherein, Θ1 represents the installation angle of the first distance measuring sensor; L1 represents the length of the first deceleration area; L2 represents the length of the second deceleration area; L3 represents the length of the parking area; H1 represents the installation height of the first distance measuring sensor.

[0019] Preferably, the calculation method of the first fixed distance measuring distance is as follows:

[0020] C1 = H1 / CosΘ1

[0021] Wherein, C1 represents the first fixed distance measuring distance; H1 represents the installation height of the first distance measuring sensor; Θ1 represents the installation angle of the first distance measuring sensor.

[0022] Preferably, the installation angle of the second distance measuring sensor is calculated based on the set length of the second deceleration area, the length of the parking area, and the installation height of the second distance measuring sensor, or the installation angle of the second distance measuring sensor is obtained by acquiring a second preset installation angle, and the second preset installation angle is calculated based on the set length of the second deceleration area, the length of the parking area, and the installation height of the second distance measuring sensor.

[0023] Preferably, the calculation method of the installation angle of the second distance measuring sensor is as follows:

[0024] Θ2 = arctan((L2 + L3) / H2)

[0025] Wherein, Θ2 represents the installation angle of the second distance measuring sensor; L2 represents the length of the second deceleration area; L3 represents the length of the parking area; H2 represents the installation height of the second distance measuring sensor.

[0026] Preferably, the calculation method of the second fixed ranging distance is as follows:

[0027] C2 = H2 / CosΘ2

[0028] Wherein, C2 represents the second fixed ranging distance; H2 represents the installation height of the second distance measuring sensor; Θ2 represents the installation angle of the second distance measuring sensor.

[0029] Preferably, it is judged whether the projected shape above the platform step changes. If so, the forklift is controlled to stop running; otherwise, the forklift is controlled to travel at a second preset speed, specifically including:

[0030] Judge whether the deformation amplification ratio of the projected part above the platform step to the projected part below the platform step exceeds a preset ratio. If so, the forklift is controlled to stop running; otherwise, the forklift is controlled to travel at a second preset speed;

[0031] Or,

[0032] Judge whether the area change of the projected part above the platform step exceeds a preset area. If so, the forklift is controlled to stop running; otherwise, the forklift is controlled to travel at a second preset speed.

[0033] Preferably, the installation height of the image sensor is the same as that of the second distance measuring sensor, and the installation angle is Θ3 = arctan((L3) / H2); the installation height of the projection device is the same as that of the first distance measuring sensor, and the installation angle is Θ4 = (arctan(L3 + L4) / H1); wherein, L4 represents the distance between the projection device and the image sensor.

[0034] On the other hand, a forklift anti-falling system based on platform edge recognition includes:

[0035] The first installation angle acquisition module is used to acquire the installation angle of the first distance measurement sensor installed at the rear of the forklift;

[0036] The first distance measurement distance acquisition module is used to acquire the first fixed distance measurement distance of the first distance measurement sensor above the platform steps based on the installation angle of the first distance measurement sensor;

[0037] The first speed limit processing module is used to determine whether the actual measurement distance of the first distance measurement sensor exceeds the first fixed distance measurement distance. If it exceeds, control the forklift to travel at a first preset speed limit; otherwise, control the forklift to travel at a normal speed;

[0038] The second installation angle acquisition module is used to acquire the installation angle of the second distance measurement sensor installed at the rear of the forklift;

[0039] The second distance measurement distance acquisition module is used to acquire the second fixed distance measurement distance of the second distance measurement sensor above the platform steps based on the installation angle of the second distance measurement sensor;

[0040] The second speed limit processing module is used to determine whether the actual measurement distance of the second distance measurement sensor exceeds the second fixed distance measurement distance. If it exceeds, control the forklift to travel at a second preset speed limit; otherwise, control the forklift to travel at the first preset speed;

[0041] The projection image acquisition module is used to acquire the projection image collected by the image sensor installed at the rear of the forklift; the projection image is projected by the projection device installed at the rear of the forklift;

[0042] The stop operation processing module is used to determine whether the projection shape above the platform steps has changed. If so, control the forklift to stop running; otherwise, control the forklift to travel at the second preset speed.

[0043] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) The present invention respectively detects the edge of the platform through two distance measurement sensors and an image sensor installed at different positions (height and / or angle). When the corresponding sensor detects the edge of the platform, corresponding area speed control is performed, realizing stable deceleration of the forklift while improving the safety of the forklift;

[0045] (2) The present invention can adjust the lengths of the two deceleration areas, the length of the parking area of the forklift, and the installation height of the two distance measurement sensors according to the height of the platform steps of the forklift and the traveling speed of the forklift, and then calculate the installation angles of the two distance measurement sensors, the image sensor, and the projection device, with flexible application and convenient installation;

[0046] (3) The present invention uses a ranging sensor and an image sensor such as a camera for automatic detection, without the need to transform the ground, and has a wide adaptability.

[0047] (4) The projection device of the present invention can use the existing blue light projection of a forklift or other projection devices, cooperate with the image sensor to identify the edge line of the platform, and stop in the stop area. The image sensor has a wide visual range and high accuracy, further improving safety. Description of the Drawings

[0048] Figure 1 is a flowchart of the forklift anti-fall method based on platform edge recognition in this embodiment;

[0049] Figure 2 is a working schematic diagram of the first ranging sensor in this embodiment detecting the platform edge and determining to enter the first-level deceleration area;

[0050] Figure 3 is a working schematic diagram of the second ranging sensor in this embodiment detecting the platform edge and determining to enter the second-level deceleration area;

[0051] Figure 4 is a driving schematic diagram of the forklift entering the deceleration state in this embodiment;

[0052] Figure 5 is a schematic diagram of the forklift stopping when the 2D camera in this embodiment detects the platform edge;

[0053] Figure 6 is a working schematic diagram of the 2D camera in this embodiment detecting the platform edge and determining to enter the parking area;

[0054] Figure 7 is a structural block diagram of the forklift anti-fall system based on platform edge recognition in this embodiment. Detailed Embodiments

[0055] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention; obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0056] In the description of the present invention, it should be noted that the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of another identical element in the process, method, article or device including the said element.

[0057] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the step identifiers S101, S102, S103, etc. are only for convenient expression and do not represent the execution order, and the corresponding execution order can be adjusted as needed.

[0058] See Figure 1 As shown, a forklift anti-fall method based on platform edge recognition includes:

[0059] S101, obtaining the installation angle of the first distance measuring sensor installed at the rear of the forklift;

[0060] S102, obtaining the first fixed ranging distance of the first distance measuring sensor above the platform step based on the installation angle of the first distance measuring sensor;

[0061] S103, judging whether the actual measured distance of the first distance measuring sensor exceeds the first fixed ranging distance. If it exceeds, controlling the forklift to travel at a first preset speed limit; otherwise, controlling the forklift to travel at a normal speed;

[0062] S104, obtaining the installation angle of the second distance measuring sensor installed at the rear of the forklift;

[0063] S105, obtaining the second fixed ranging distance of the second distance measuring sensor above the platform step based on the installation angle of the second distance measuring sensor;

[0064] S106, judging whether the actual measured distance of the second distance measuring sensor exceeds the second fixed ranging distance. If it exceeds, controlling the forklift to travel at a second preset speed limit; otherwise, controlling the forklift to travel at the first preset speed;

[0065] S107, obtaining the projection image collected by the image sensor installed at the rear of the forklift; the projection image is projected by a projection device installed at the rear of the forklift;

[0066] S108, judging whether the projection shape above the platform step has changed. If so, controlling the forklift to stop running; otherwise, controlling the forklift to travel at the second preset speed.

[0067] In this embodiment, the execution entity of a forklift anti-falling method based on platform edge recognition can be implemented by a controller installed on the forklift. Of course, it can also be implemented by a controller or a processor installed elsewhere, as long as it can be respectively connected to the first distance sensor, the second distance sensor, the projection device, and the image sensor and can communicate with each other.

[0068] Specifically, the first distance sensor is installed behind the overhead guard of the forklift; the first distance sensor is installed behind the counterweight of the forklift. The installation height of the first distance sensor is greater than the installation height of the second distance sensor. The installation height of the projection device is equal to the installation height of the first distance sensor, and the installation height of the image sensor is equal to the installation height of the second distance sensor.

[0069] In other embodiments, the installation height of the first distance sensor can also be equal to the installation height of the second distance sensor, but their installation angles need to be different. It should be noted that the installation heights of the first distance sensor, the second distance sensor, the projection device, and the image sensor can be set according to actual applications, and the present invention does not make any restrictions.

[0070] Specifically, the installation angle of the first distance sensor is calculated based on the set lengths of the first deceleration area, the second deceleration area, the parking area, and the installation height of the first distance sensor. Alternatively, the installation angle of the first distance sensor is obtained by acquiring a first preset installation angle, and the first preset installation angle is calculated based on the set lengths of the first deceleration area, the second deceleration area, the parking area, and the installation height of the first distance sensor. That is, the installation angle of the first distance sensor can be calculated online by the controller according to the set lengths of the first deceleration area, the second deceleration area, the parking area, and the installation height of the first distance sensor. Or, the first preset installation angle can be calculated based on the lengths of the first deceleration area, the second deceleration area, the parking area, and the installation height of the first distance sensor, and the first preset installation angle is set in the controller. During real-time control, only this first preset installation angle needs to be called.

[0071] In this embodiment, the calculation method of the installation angle of the first distance sensor is as follows:

[0072] Θ1 = arctan((L1 + L2 + L3) / H1)

[0073] Where, Θ1 represents the installation angle of the first distance sensor; L1 represents the length of the first deceleration area; L2 represents the length of the second deceleration area; L3 represents the length of the parking area; H1 represents the installation height of the first distance sensor.

[0074] Correspondingly, the calculation method of the first fixed ranging distance is as follows:

[0075] C1 = H1 / CosΘ1

[0076] Wherein, C1 represents the first fixed ranging distance; H1 represents the installation height of the first ranging sensor; Θ1 represents the installation angle of the first ranging sensor.

[0077] The installation angle of the second ranging sensor is calculated based on the set length of the second deceleration area, the length of the parking area, and the installation height of the second ranging sensor, or the installation angle of the second ranging sensor is obtained by obtaining a second preset installation angle, and the second preset installation angle is calculated based on the set length of the second deceleration area, the length of the parking area, and the installation height of the second ranging sensor. That is, the installation angle of the second ranging sensor can be calculated online by the controller according to the set length of the second deceleration area, the length of the parking area, and the installation height of the second ranging sensor, or the second preset installation angle can be calculated according to the length of the second deceleration area, the length of the parking area, and the installation height of the second ranging sensor, and the second preset installation angle is set in the controller. During real-time control, only this second preset installation angle needs to be called.

[0078] In this embodiment, the calculation method of the installation angle of the second ranging sensor is as follows:

[0079] Θ2 = arctan((L2 + L3) / H2)

[0080] Wherein, Θ2 represents the installation angle of the second ranging sensor; L2 represents the length of the second deceleration area; L3 represents the length of the parking area; H2 represents the installation height of the second ranging sensor.

[0081] Correspondingly, the calculation method of the second fixed ranging distance is as follows:

[0082] C2 = H2 / CosΘ2

[0083] Wherein, C2 represents the second fixed ranging distance; H2 represents the installation height of the second ranging sensor; Θ2 represents the installation angle of the second ranging sensor.

[0084] Further, it is determined whether the projected shape above the platform step changes. If so, the forklift is controlled to stop running; otherwise, the forklift is controlled to travel at a second preset speed, specifically including:

[0085] It is determined whether the deformation magnification ratio of the projected part above the platform step to the projected part below the platform step exceeds a preset ratio. If so, the forklift is controlled to stop running; otherwise, the forklift is controlled to travel at a second preset speed;

[0086] Or,

[0087] Determine whether the area change of the projection part above the platform steps exceeds a preset area. If so, control the forklift to stop running; otherwise, control the forklift to travel at a second preset speed.

[0088] In this embodiment, the installation angle of the image sensor is Θ3 = arctan((L3) / H2); the installation angle of the projection device is Θ4 = (arctan(L3 + L4) / H1); where L4 represents the distance between the projection device and the image sensor.

[0089] The following will be described through a specific embodiment.

[0090] According to the actual working conditions, the first deceleration area L1 = 2.5m, the second deceleration area L2 = 2m, the parking area L3 = 2m, the installation height H1 of the first distance sensor and the projection device = 2m, the installation height H2 of the second distance sensor and the image sensor = 1m, and the platform height H3 = 0.5m. Obtain the installation angle Θ1 of the first distance sensor = arctan((2.5 + 2 + 1) / 2) = 70°. When the forklift travels at a normal speed, the ranging distance of the first distance sensor is C1 = 2 / Cos70° = 3.15m. Refer to Figure 2 as shown (only the relevant measurements of the first distance sensor are shown). If the actual measured distance C of the first distance sensor 1实 ≥ 3.15m, it means that the forklift enters the first deceleration area at this time and travels at a speed limited by the first preset speed set by the forklift controller (for example, the speed limit is 5km / h). Obtain the installation angle of the second distance sensor: Θ2 = arctan((2 + 1) / 1) = 71°, and the ranging distance is C2 = H2 / CosΘ2 = 1 / cos71° = 3.07m. Refer to Figure 3 as shown (only the relevant parameters of the second distance sensor measurement are shown). If the actual measured distance C of the second distance sensor 2实 > 3.07, it means that the forklift enters the second deceleration area at this time and is speed-limited according to the second preset speed set by the forklift controller (for example, the speed limit is 2km / h). When the forklift advances in the second deceleration area, an image sensor (camera) is installed on the counterweight. According to the set parking area L3 = 1m and the installation height H2 = 1m of the 2D camera sensor, obtain the installation angle Θ2 of the 2D camera = arctan(1 / 1) = 45°. Refer to Figure 4 as shown. When the forklift travels far from the edge of the platform, the magnification ratio K value detected by the 2D camera image sensor is 1. Refer to Figure 5 and Figure 6(Only the parameters related to the measurement of the 2D camera image sensor are shown.) As shown in the figure, for the image captured by the camera image sensor, it is detected that the shape of the partial projection has deformed, and the deformation contrast coefficient K of the two steps 实 =(H1 + H3) / H1 = 1.25 ≥ 1. At this time, the forklift enters the parking area and stops.

[0091] It should be noted that the shape, size, and color of the projection by the projection device can all be set according to actual needs. According to the principle of the linear propagation of light, the deformation generated by the projection on the two step planes (above and below the platform steps) is linearly amplified in direct proportion to the projection distance. Therefore, the lower the projection lamp is installed, the greater the deformation coefficient of the projection on the two step planes for comparison, that is, the more obvious the change in the shape and size of the projection of the two steps, and the higher the detection accuracy. At the same time, the detection accuracy can be optimized by optimizing the shape, size, or color of the projected pattern.

[0092] For example, a 2D camera with a resolution of 1920*1080, a frame rate of 10fps, a horizontal field of view angle of 100°, and a vertical field of view angle of 40°. At a distance of 0.5 meters, the actual field of view size that can be seen is a field of view range of 0.95m * 0.33m; at a distance of 2.23 meters, the actual field of view size that the camera can see is a field of view range of 3.80m * 1.34m. Therefore, it can be theoretically calculated that at a distance of 2.0m from the camera, the accuracy in the X direction = 380cm ÷ 1920 = 0.19cm; the accuracy in the Y direction = 134cm ÷ 1080 = 0.12cm.

[0093] As follows, it will be determined whether to control the forklift to stop running by judging the change in the area of the projection part above the platform step. Specifically, a solid blue circle with a ground projection radius of 10cm is projected, and the center of the circle is 2m away from the rear of the vehicle (the distance from the camera to the circle is approximately 2.23m). The method uses the detection that the shape and area of the blue circle projected onto the ground have changed by a quarter or more as the basis for identifying the platform edge line, triggering automatic parking. Since the diameter of the projection circle is 20cm, the corresponding change for a quarter circle is a change in diameter of 5cm. At a distance of 2.0m from the camera, the recognition accuracy error in the X direction of the label = 0.19cm ÷ 5cm = 3.8%; the recognition accuracy error in the Y direction of the label = 0.12cm ÷ 5cm = 2.4%.

[0094] Since the second ranging sensor detects and enables the speed limit function, the speed limit for the forklift to reverse is 2km / h (0.56m / s). The camera detects and calculates that the output brake control time is 2S, and it takes an additional 1.5s to brake to a stop state. In total, it has reversed and traveled 1.54m. At this time, there is still a reserved safety distance of 0.46m from the platform edge line. The reserved safety distance range for parking can be set by adjusting the speed limit and braking deceleration according to actual needs.

[0095] See Figure 7 As shown, a forklift anti - fall system based on platform edge recognition includes:

[0096] The first installation angle acquisition module 701 is used to acquire the installation angle of the first distance measuring sensor installed behind the forklift;

[0097] The first distance measurement distance acquisition module 702 is used to acquire the first fixed distance measurement distance of the first distance measuring sensor above the platform step based on the installation angle of the first distance measuring sensor;

[0098] The first speed limit processing module 703 is used to determine whether the actual measurement distance of the first distance measuring sensor exceeds the first fixed distance measurement distance. If it exceeds, control the forklift to travel at a first preset speed limit; otherwise, control the forklift to travel at a normal speed;

[0099] The second installation angle acquisition module 704 is used to acquire the installation angle of the second distance measuring sensor installed behind the forklift;

[0100] The second distance measurement distance acquisition module 705 is used to acquire the second fixed distance measurement distance of the second distance measuring sensor above the platform step based on the installation angle of the second distance measuring sensor;

[0101] The second speed limit processing module 706 is used to determine whether the actual measurement distance of the second distance measuring sensor exceeds the second fixed distance measurement distance. If it exceeds, control the forklift to travel at a second preset speed limit; otherwise, control the forklift to travel at the first preset speed;

[0102] The projection image acquisition module 707 is used to acquire the projection image collected by the image sensor installed behind the forklift; the projection image is projected by the projection device installed behind the forklift;

[0103] The stop operation processing module 708 is used to determine whether the projection shape above the platform step has changed. If so, control the forklift to stop running; otherwise, control the forklift to travel at the second preset speed.

[0104] The execution entity of a forklift anti - fall system based on platform edge recognition is a controller. The specific implementation of each module is the same as that of a forklift anti - fall method based on platform edge recognition. The installation positions of the controller, the first distance measuring sensor, the second distance measuring sensor, the projection device and the image sensor are also the same as those of a forklift anti - fall method based on platform edge recognition, and will not be repeated in this embodiment.

[0105] The above are only the preferred specific embodiments of the present invention; however, the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and its improved concept of the present invention, making equivalent substitutions or changes, should be covered by the protection scope of the present invention.

Claims

1. A forklift anti-fall method based on platform edge recognition, characterized in that, Including: Obtain the installation angle of the first distance measurement sensor installed at the rear of the forklift; Based on the installation angle of the first distance measurement sensor, obtain the first fixed distance measurement distance of the first distance measurement sensor above the platform steps; Judge whether the actual measurement distance of the first distance measurement sensor exceeds the first fixed distance measurement distance. If it exceeds, control the forklift to travel at a speed limited by the first preset speed; otherwise, control the forklift to travel at a normal speed; Obtain the installation angle of the second distance measurement sensor installed at the rear of the forklift; Based on the installation angle of the second distance measurement sensor, obtain the second fixed distance measurement distance of the second distance measurement sensor above the platform steps; Judge whether the actual measurement distance of the second distance measurement sensor exceeds the second fixed distance measurement distance. If it exceeds, control the forklift to travel at a speed limited by the second preset speed; otherwise, control the forklift to travel at the first preset speed; Obtain the projection image collected by the image sensor installed at the rear of the forklift; the projection image is projected by the projection device installed at the rear of the forklift; Judge whether the projection shape above the platform steps has changed. If so, control the forklift to stop running; otherwise, control the forklift to travel at the second preset speed.

2. The forklift anti-fall method based on platform edge recognition according to claim 1, characterized in that, The installation angle of the first distance measurement sensor is calculated and obtained based on the set lengths of the first deceleration area, the second deceleration area, the parking area, and the installation height of the first distance measurement sensor. Alternatively, the installation angle of the first distance measurement sensor is obtained by acquiring a first preset installation angle, and the first preset installation angle is calculated and obtained based on the set lengths of the first deceleration area, the second deceleration area, the parking area, and the installation height of the first distance measurement sensor.

3. The forklift anti-fall method based on platform edge recognition according to claim 2, wherein, The calculation method of the installation angle of the first distance measurement sensor is as follows: Θ1 = arctan((L1 + L2 + L3) / H1) Where, Θ1 represents the installation angle of the first distance measurement sensor; L1 represents the length of the first deceleration area; L2 represents the length of the second deceleration area; L3 represents the length of the parking area; H1 represents the installation height of the first distance measurement sensor.

4. The forklift anti-falling method based on platform edge recognition according to claim 2, characterized in that, The calculation method of the first fixed distance measurement distance is as follows: C1 = H1 / CosΘ1 Where, C1 represents the first fixed distance measurement distance; H1 represents the installation height of the first distance measurement sensor; Θ1 represents the installation angle of the first distance measurement sensor.

5. The forklift anti-fall method based on platform edge recognition according to claim 1, characterized in that, The installation angle of the second distance measurement sensor is calculated and obtained based on the set lengths of the second deceleration area, the parking area, and the installation height of the second distance measurement sensor. Alternatively, the installation angle of the second distance measurement sensor is obtained by acquiring a second preset installation angle, and the second preset installation angle is calculated and obtained based on the set lengths of the second deceleration area, the parking area, and the installation height of the second distance measurement sensor.

6. The forklift anti-fall method based on platform edge recognition according to claim 5, characterized in that The calculation method of the installation angle of the second distance measurement sensor is as follows: Θ2 = arctan((L2 + L3) / H2) Where, Θ2 represents the installation angle of the second distance measurement sensor; L2 represents the length of the second deceleration area; L3 represents the length of the parking area; H2 represents the installation height of the second distance measurement sensor.

7. The forklift anti-fall method based on platform edge recognition according to claim 5, characterized in that, The calculation method of the second fixed distance measurement distance is as follows: C2 = H2 / CosΘ2 Among them, C2 represents the second fixed ranging distance; H2 represents the installation height of the second ranging sensor; Θ2 represents the installation angle of the second ranging sensor.

8. The forklift anti-fall method based on platform edge recognition according to claim 1, characterized in that, Judge whether the projected shape above the platform steps has changed. If so, control the forklift to stop running; otherwise, control the forklift to travel at a second preset speed, specifically including: Judge whether the deformation magnification ratio between the projected part above the platform steps and the projected part below the platform steps exceeds a preset ratio. If so, control the forklift to stop running; otherwise, control the forklift to travel at a second preset speed; Or, Judge whether the area change of the projected part above the platform steps exceeds a preset area. If so, control the forklift to stop running; otherwise, control the forklift to travel at a second preset speed.

9. The forklift anti-falling method based on platform edge recognition according to claim 1, wherein The installation height of the image sensor is the same as that of the second ranging sensor, and the installation angle is Θ3 = (arctan(L3) / H2); the installation height of the projection device is the same as that of the first ranging sensor, and the installation angle is Θ4 = (arctan(L3 + L4) / H1); where L4 represents the distance between the projection device and the image sensor.

10. A forklift anti-fall system based on platform edge recognition, characterized in that, Including: The first installation angle acquisition module is used to acquire the installation angle of the first ranging sensor installed behind the forklift; The first ranging distance acquisition module is used to acquire the first fixed ranging distance of the first ranging sensor above the platform steps based on the installation angle of the first ranging sensor; The first speed limit processing module is used to judge whether the actual measured distance of the first ranging sensor exceeds the first fixed ranging distance. If it exceeds, control the forklift to travel at a first preset speed limit; otherwise, control the forklift to travel at a normal speed; The second installation angle acquisition module is used to acquire the installation angle of the second ranging sensor installed behind the forklift; The second ranging distance acquisition module is used to acquire the second fixed ranging distance of the second ranging sensor above the platform steps based on the installation angle of the second ranging sensor; The second speed limit processing module is used to judge whether the actual measured distance of the second ranging sensor exceeds the second fixed ranging distance. If it exceeds, control the forklift to travel at a second preset speed limit; otherwise, control the forklift to travel at a first preset speed; The projection image acquisition module is used to acquire the projection image collected by the image sensor installed behind the forklift; the projection image is projected by the projection device installed behind the forklift; The stop running processing module is used to judge whether the projected shape above the platform steps has changed. If so, control the forklift to stop running; otherwise, control the forklift to travel at a second preset speed.

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