Collision prevention system

Abstract

To prevent the loading section, which moves up and down while traveling, from colliding with objects within the facility. [Solution] The collision prevention system S includes a front camera 8, a rear camera 9, an object position estimation unit, a loader position estimation unit, a distance estimation unit, and a threshold setting unit. The front camera 8 captures an image in front of the loader CP to generate a first image, and the rear camera 9 captures an image in front of and above the rear camera 9, including the loader CP, to generate a second image. The object position estimation unit estimates the future position of an object within a facility based on a plurality of consecutive first and second images. The loader position estimation unit estimates the future position of the loader CP based on a plurality of consecutive first and second images. The distance estimation unit estimates the distance between the future position of the object and the future position of the loader CP. The threshold setting unit changes the threshold for the movement speed of the loader CP based on the estimated distance so that the loader CP does not collide with the object.

Description

[Technical Field]

[0001] The present invention relates to a collision prevention system for a forklift. [Background technology]

[0002] Patent Document 1 discloses that the forks of a forklift can be raised and lowered while the vehicle is traveling. According to this patent document, the driver may start raising and lowering the forks and rotating them while the vehicle is traveling, thereby reducing the time it takes to raise and lower the forks and rotate them at the loading / unloading position. However, if the forks are raised while the vehicle is traveling, there is a possibility that the forks or the load carried by the forks (collectively referred to as the loading section) may come into contact with overhead cranes, entrances and exits within the facility, etc.

[0003] Patent Document 2 discloses a safety device for a forklift. This safety device is equipped with a non-contact measuring device near the fork, and by notifying the driver of any obstacles detected by this non-contact measuring device, it prevents the fork from colliding with an obstacle ahead.

[0004] Facilities where forklifts are used often contain objects such as shutters, overhead cranes, and mobile racks. A shutter 200 shown in FIG. 8 includes a shutter body 201 and a pillar 202 that guides the shutter body. The shutter body 201 moves up and down to open and close an entrance. An overhead crane 300 shown in FIG. 9 includes a hook 301 for suspending a load L, a wire 302 for raising and lowering the hook 301, and a trolley 303 for moving the hook 301 horizontally. The overhead crane 300 raises and lowers the load L and moves it horizontally together with the hook 301. It is difficult for a driver to predict whether such moving objects 200, 300 will collide with the forks 5 of a forklift 100 that are being raised or lowered while the forklift 100 is traveling. The safety device of Patent Document 2 does not anticipate such a collision. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-059436 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-195334 Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, an object of the present invention is to provide a collision prevention system that can prevent a loading section that is raised and lowered while traveling from colliding with an object within a facility. [Means for solving the problem]

[0007] In order to solve the above problems, the collision prevention system according to the present invention comprises: a front camera disposed on the forklift to capture an image in front of a loading section of the forklift and generate a first image; a rear camera disposed on the forklift, capturing an image of both or either a front side including the loading section and an upper side including the loading section, and generating a second image; an object position estimation unit that has previously undergone machine learning to estimate the future movement position of an object at each time point based on a plurality of consecutive first images including an object within a facility (hereinafter simply referred to as "object") and a plurality of consecutive second images including the object, and the times at which the first and second images were taken; a loading unit position estimation unit that has previously undergone machine learning to estimate a future position of the loading unit at each time point based on a plurality of consecutive first images and a plurality of consecutive second images and the times at which the first and second images were captured; a distance estimation unit that estimates a distance from the loading unit to an object when the object is placed in the moving direction of the loading unit due to the movement of the object, and a distance between the loading unit and an object that has already been placed in the moving direction of the loading unit; The system further includes a threshold setting unit that changes a threshold value of the moving speed of the loading unit by referring to the distance estimated by the distance estimation unit so that the loading unit does not collide with the object.

[0008] In the collision prevention system, the threshold value of the moving speed of the load unit preferably includes both or one of a maximum traveling speed and a maximum traveling acceleration.

[0009] In the collision prevention system, the threshold value for the moving speed of the load unit preferably includes both or one of a maximum lifting speed of the load unit and a maximum lifting / lowering acceleration of the load unit.

[0010] In the collision prevention system, the threshold value for the load movement speed preferably includes a minimum descent speed and / or a minimum descent acceleration.

[0011] The collision prevention system is preferably configured such that the threshold range includes 0, and the movement of the load unit can be substantially stopped.

[0012] The collision avoidance system preferably comprises: The forklift has a brake, The collision prevention system further includes a stopping unit that controls the brakes to stop the forklift when the threshold value of the maximum traveling speed or maximum traveling acceleration is zero.

[0013] In the collision prevention system, the object preferably includes a shutter that moves up and down to open and close.

[0014] In the collision prevention system, the object preferably includes an overhead crane.

[0015] In the collision prevention system, the object preferably includes a movable shelf.

[0016] Preferably, the object of the collision prevention system also includes walls, racks, and ceilings that are fixed within the facility.

[0017] The collision prevention system preferably further includes a notification unit that, when the threshold value for the moving speed of the load unit is changed and the load unit is decelerated or stopped, notifies the driver of the deceleration or stoppage.

[0018] In order to solve the above problem, a forklift according to the present invention is equipped with the above collision prevention system.

[0019] In order to solve the above problem, a collision prevention program according to the present invention includes: A collision prevention program used in a collision prevention system having a front camera that takes an image of the area in front of a loading section of a forklift and generates a first image, a rear camera that takes an image of the area in front of the loading section and / or the area above the loading section and generates a second image, and a computer, On the computer, an object position estimation unit that has previously undergone machine learning to estimate the future movement position of an object at each time point based on a plurality of consecutive first images including an object (hereinafter simply referred to as the object) within a facility and a plurality of consecutive second images including the object, and the times at which the first and second images were taken; a loading unit position estimation unit that has previously undergone machine learning to estimate a future position of the loading unit at each time point based on a plurality of consecutive first images and a plurality of consecutive second images and the times at which the first and second images were captured; a distance estimation unit that estimates a distance from the loading unit to an object when the object is placed in the moving direction of the loading unit due to the movement of the object, and a distance between the loading unit and an object that has already been placed in the moving direction of the loading unit; The threshold setting unit changes the threshold value of the moving speed of the loading unit by referring to the moving position of the object and the moving position of the loading unit so that the loading unit does not collide with the object. [Effects of the Invention]

[0020] The collision prevention system according to the present invention can prevent the forks moving up and down from colliding with objects within the facility while traveling. [Brief explanation of the drawings]

[0021] [Figure 1] 1A is a side view showing a forklift of a collision prevention system according to one embodiment of the present invention, and FIG. 1B is an enlarged view of a part B of FIG. [Figure 2] FIG. 2 is a block diagram of a collision prevention system. [Figure 3] Schematic diagram showing the movement of objects and payloads within the facility, where A is a top view and B is a side view. [Figure 4] 4 is a graph showing the operation of a collision prevention system. [Figure 5] 10 is another graph illustrating the operation of the collision prevention system. [Figure 6] FIG. 4 is a flow chart showing the operation of the collision prevention system. [Figure 7] 1A and 1B are side views showing the effect of the present invention, where A shows the conventional operation, and B and C show the operation of the present invention. [Figure 8] FIG. 1 is a diagram showing a conventional forklift that moves up and down while moving, and a shutter that opens and closes up and down. [Figure 9] 1 is a diagram showing a conventional forklift that moves up and down while moving, and an overhead crane. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, an embodiment of a collision prevention system of the present invention and a forklift truck equipped with the system will be described with reference to the accompanying drawings.

[0023] <Forklift configuration> FIG. 1A is a side view showing a forklift F equipped with a collision prevention system S of this embodiment. In this embodiment, the forklift F is a counter-load forklift powered by a battery, but this is merely an example and the present invention is not limited to this. For example, the forklift according to the present invention may be an engine-driven forklift or a reach forklift. Note that the axes in the accompanying drawings are based on the forklift F, with the X axis indicating the front-to-rear direction, the Y axis indicating the left-to-right direction, and the Z axis indicating the up-to-down direction.

[0024] As shown in Fig. 1A, the forklift F includes a plurality of wheels 2, a vehicle body 3, left and right masts 4, left and right forks 5, a backrest 6, a head guard 7, a front camera 8, and a rear camera 9. This forklift F has the same configuration as the forklift F in Figs. 8 and 9, except that it is equipped with a collision prevention system S. Therefore, for the rear view of the forklift F, please refer to Fig. 8 or 9.

[0025] The wheels 2 are arranged on the left and right sides of the front and rear under the vehicle body 3. The left and right masts 4 are extendable and are arranged in front of the vehicle body 3. The masts 4 are connected to the forks 5 and backrest 6 so that they can be raised and lowered. Although not shown in FIG. 1A, the forks 5 carry a pallet and load. The forks 5, backrest 6, pallet, and load correspond to the "loading portion" according to the present invention. The head guard 7 is arranged above the vehicle body 3.

[0026] The front camera 8 is composed of two cameras, and as shown in FIG. 1B, is disposed inside the front parts of the left and right forks 5, respectively. The front cameras 8 photograph the area in front of the forks 5 (loading part CP) and generate a first image. However, the number of front cameras 8 is merely an example, and the number of front cameras 8 is not particularly limited. For example, the front camera 8 may be composed of one camera or three or more cameras. Furthermore, the location where the front camera 8 is disposed is not particularly limited, and may be, for example, the rear side of the horizontal part of the left and right forks 5 (the part that does not contact the pallet), or may be somewhere other than the forks 5. Therefore, for example, the location where the front camera 8 is disposed may be directly disposed on the backrest 6, or may be disposed on the backrest 6 via a bracket.

[0027] The rear camera 9 is composed of two cameras, each of which is disposed on the outside of the lower part of the mast 4, as shown in FIG. 1A. The rear camera 9 captures an image of both or either the front including the loading part CP and the upper part including the loading part CP, and generates a second image. The number of rear cameras 9 is merely an example, and the number of rear cameras 9 is not particularly limited. For example, the rear camera 9 may be composed of one camera or three or more cameras. Furthermore, the rear camera 9 may be connected to the mast 4 via a bracket or the like whose orientation changes as the loading part CP is raised or lowered in order to capture an image of the loading part CP. Furthermore, the location at which the rear camera 9 is disposed is not limited to the mast 4.

[0028] 2 is a block diagram of the collision prevention system S. As shown in FIG. 2, the forklift F further includes a drive unit 10, a brake 12, a lift unit 14, a speaker 15, and a control unit 20.

[0029] The drive unit 10 is made up of drive parts such as a motor and is connected to either the front or rear wheels 2. The drive unit 10 drives the connected wheels 2 to move the forklift F forward and backward. When the present invention is applied to an engine-powered forklift, the drive unit 10 is made up of drive parts including the engine.

[0030] The brake 12 is disposed on the wheel 2 connected to the drive unit 10, and is configured to stop the rotation of the wheel 2. The type of the brake 12 is not particularly limited.

[0031] The lifting section 14 has a lift cylinder connected to the mast 4 that expands and contracts with the hydraulic pressure of hydraulic oil, and the expansion and contraction of the lift cylinder expands and contracts the mast 4. The loading section CP rises and falls along the mast 4 as the mast 4 expands and contracts.

[0032] The speaker 15 is disposed on the head guard 7, but this is merely an example, and the location of the speaker 15 is not particularly limited. The speaker 15 outputs an alarm sound to notify the driver of deceleration or stopping of traveling, and deceleration, stopping, or acceleration of lifting or lowering of the loading part CP by the collision prevention system S. The alarm sound may be a specific voice or a beep sound.

[0033] The control unit 20 is configured by a computer arranged inside the vehicle body 3, and has an arithmetic unit, a storage device, and a memory. The storage device stores a collision prevention program that causes the computer to function as an object position estimation unit 22, a loading unit position estimation unit 24, a distance estimation unit 26, a threshold setting unit 28, a lift control unit 29, a drive control unit 30, a stopping unit 32, and a notification unit 34, all of which will be described later.

[0034] <Functional configuration of collision prevention system> Next, a description will be given of the functional configuration of the collision prevention system S. As shown in Fig. 2, the control unit 20 has an object position estimation unit 22, a loading unit position estimation unit 24, a distance estimation unit 26, a threshold value setting unit 28, a lifting / lowering control unit 29, a drive control unit 30, a stopping unit 32, and a notification unit 34.

[0035] The object position estimation unit 22 has previously performed machine learning to estimate the future movement position of object O at each time point based on a series of first images including object O (hereinafter simply referred to as "object O") within the facility and a series of second images including object O, and the times at which the first and second images were taken.

[0036] The object O includes, for example, a shutter 200 that moves up and down as shown in FIG. 8, an overhead crane 300 as shown in FIG. 9, and a movable shelf (not shown). That is, the object position estimation unit 22 has previously performed machine learning using first and second images generated by photographing the shutter 200, the overhead crane 300, and the movable shelf. For example, in the case of an overhead crane 300, the object position estimation unit 22 has been trained to recognize not only the hook 301 that is part of the overhead crane 300 but also the load L suspended by the overhead crane 300 as the overhead crane 300, and to estimate the movement position of the load L. Furthermore, in the case of a movable shelf, the object position estimation unit 22 has been trained to recognize any object protruding from the movable shelf as part of the movable shelf, and to estimate the movement position of the object.

[0037] FIG. 3 is a schematic diagram showing the movement of object O and loading unit CP within a facility, with FIG. 3A being a top view and FIG. 3B being a side view. When first and second images that change over time are input, object position estimation unit 22 estimates the direction of movement MD2 and speed of movement of object O from the changes over time in the first and second images. This allows object position estimation unit 22 to estimate the current position OP1 and future position OP2 of object O. The future position refers to the position several seconds or several tens of seconds from now.

[0038] Note that each "position" in the present invention may be, for example, a horizontal or vertical coordinate. When the coordinate is specified as an absolute coordinate, for example, the forklift F may have a coordinate specifying device that uses a GPS or the like to specify the coordinate of the current position.

[0039] The object position estimation unit 22 estimates the position of not only a moving object O but also an object O that is fixed within the facility. This fixed object O corresponds to the "object already placed in the direction of movement of the loading unit" of the present invention. The fixed object O may include a wall, a rack, or a ceiling. Since the fixed object O does not move, the moving position of the object O at each time estimated by the object position estimation unit 22 for this fixed object O will always be the same, excluding estimation errors.

[0040] The loader position estimation unit 24 has previously undergone machine learning to estimate the future movement position of the loader CP at each time point based on a plurality of consecutive first images and a plurality of consecutive second images and the times at which the first and second images were captured. When the loader position estimation unit 24 receives the first and second images, which change over time, it estimates the movement direction MD1 and movement speed of the loader CP from the changes over time in the first and second images, as shown in Fig. 3. This allows the loader position estimation unit 24 to estimate the current position LP1 and future position LP2 of the loader CP.

[0041] The distance estimation unit 26 estimates the distance from the loader CP to the object O when the object O is placed in the movement direction MD1 of the loader CP due to the movement of the object O. Explaining with reference to Fig. 3, the distance estimation unit 26 estimates a horizontal distance D1 between a future position LP2 of the loader CP and a future position OP2 of the object O in the horizontal direction in Fig. 3A. The distance estimation unit 26 also estimates a vertical distance D2 between the future position LP2 of the loader CP and a future position OP2 of the object O in the vertical direction in Fig. 3B.

[0042] The threshold setting unit 28 refers to the distances D1 and D2 estimated by the distance estimation unit 26 and changes the threshold value of the moving speed of the loader CP so that the loader CP does not collide with the object O.

[0043] For example, since the movement speed of the loading unit CP in the horizontal direction is the movement speed (traveling speed) of the forklift F, the threshold value for the movement speed in the horizontal direction changed by the threshold setting unit 28 includes both or one of the maximum travel speed and maximum travel acceleration of the forklift F. Furthermore, since the movement speed of the loading unit CP in the vertical direction is the lifting / lowering speed of the forks 5, the threshold value for the movement speed in the vertical direction changed by the threshold setting unit 28 includes both or one of the maximum lifting / lowering speed and maximum lifting / lowering acceleration of the forks 5. Furthermore, in this embodiment, the threshold value for the movement speed in the vertical direction changed by the threshold setting unit 28 includes both or one of the minimum lifting / lowering speed and minimum lifting / lowering acceleration of the forks 5.

[0044] To prevent the loading unit CP from colliding with the object O, the future position OP2 of the object O and the future position LP2 of the loading unit CP must not overlap in the horizontal direction, or the height of the future position LP2 of the loading unit CP must be lower than the height of the future position OP2 of the object O. Therefore, for example, if a forklift F is raising its forks 5 while traveling and the loading unit CP is about to collide with the object O, the collision can be prevented by slowing down the lifting speed of the loading unit CP or by stopping the lifting of the loading unit CP. Alternatively, if a forklift F is raising its forks 5 while traveling and the loading unit CP is about to collide with the object O, the collision can be prevented by slowing down the traveling speed of the forklift F or by stopping the traveling of the forklift F.

[0045] Therefore, the threshold setting unit 28 changes the threshold value of the rising speed (moving speed) of the loading unit CP so that the distance D2 between the future position LP2 of the loading unit CP in the vertical direction and the future position OP2 of the object O is longer than a predetermined distance, and so that the future position LP2 of the loading unit CP is lower than the future position OP2 of the object O.

[0046] Furthermore, the threshold setting unit 28 may set the threshold to 0. By setting the threshold to 0, the threshold setting unit 28 stops the lifting of the loading unit CP. That is, the threshold setting unit 28 determines a height that serves as a reference for stopping the lifting of the loading unit CP, in other words, a limit value for the future position LP2 of the loading unit CP, based on the future position OP2 of the object O, and determines a threshold value so that the future position LP2 of the loading unit CP is equal to or less than this limit value, thereby preventing a collision.

[0047] Furthermore, the threshold setting unit 28 changes the threshold value for the traveling speed of the forklift F (the horizontal movement speed of the loading unit CP) so that the distance D1 between the future position LP2 of the loading unit CP and the future position OP2 of the object O in the horizontal direction becomes longer than a predetermined distance. The threshold setting unit 28 may also set the threshold value for the traveling speed to 0. This causes the threshold setting unit 28 to stop the traveling of the forklift F.

[0048] When the threshold value setting unit 28 changes the threshold value, if a collision can be prevented by changing the threshold value for the ascent speed (travel speed) of the loading unit CP, the threshold value for the travel speed does not need to be changed. This allows the threshold value setting unit 28 to avoid a collision without increasing the travel time of the forklift F.

[0049] The lifting / lowering control unit 29 is configured to control the lifting / lowering unit 14 in accordance with the operation of the driver H within the set threshold range, and raise, lower or stop the forks 5 (loading unit CP). Therefore, the lifting / lowering control unit 29 decelerates, accelerates or stops the lifting / lowering of the lifting / lowering unit 14 depending on the threshold value changed by the threshold value setting unit 28, regardless of the operation of the driver H.

[0050] That is, when the maximum ascending speed changed by the threshold setting unit 28 is slower than the ascending speed before the change, the lift control unit 29 reduces the ascending speed of the lifting unit 14. Also, when the maximum ascending acceleration changed by the threshold setting unit 28 is smaller than the ascending acceleration before the change, the lift control unit 29 reduces the acceleration of the ascent of the lifting unit 14. In addition, when the threshold setting unit 28 changes the threshold for the maximum ascending speed of the lifting unit 14 to 0, the lift control unit 29 stops the ascent of the loading unit CP.

[0051] FIG. 4 shows the rise of the loading unit CP when the forklift F passes through the rising shutter 200 at the entrance / exit. As shown in FIG. 4, if the threshold value is not changed, the height of the loading unit CP will be higher than the height of the shutter 200 when the forklift F arrives (when the forklift F passes through the shutter), causing the loading unit CP to collide with the shutter 200. However, the threshold value is changed by the threshold value setting unit 28, and the lifting control unit 29 reduces the lifting speed of the lifting unit 14, thereby correcting the height of the loading unit CP to be lower when the forklift F arrives. As a result, the collision prevention system S can prevent the loading unit CP from colliding with the shutter 200 without reducing the traveling speed of the forklift F. As described above, when the threshold value for the maximum lifting speed of the lifting unit 14 is 0, the lifting control unit 29 stops the lifting of the lifting unit 14 to prevent a collision.

[0052] Furthermore, the lift control unit 29 increases the descent speed of the lift unit 14 when the minimum descent speed changed by the threshold setting unit 28 is faster than the descent speed before the change, and increases the descent acceleration of the lift unit 14 when the minimum descent acceleration changed by the threshold setting unit 28 is greater than the descent acceleration before the change.

[0053] 5 shows the descent of loading unit CP as forklift F passes overhead crane 300 as it rises. As shown in FIG. 5, if the threshold value is not changed, the height of loading unit CP will be higher than the height of overhead crane 300 when it reaches the target, causing loading unit CP to collide with overhead crane 300. However, by changing the threshold value using threshold setting unit 28 and increasing the descent speed of lifting unit 14 using lifting control unit 29, the height of loading unit CP when it reaches the target is corrected to be lower. As a result, collision prevention system S can prevent loading unit CP from colliding with overhead crane 300 without reducing the traveling speed of forklift F.

[0054] The drive control unit 30 is configured to control the drive unit 10 in accordance with the operation of the driver H within the set threshold range, and to travel the forklift F. Therefore, the drive control unit 30 decelerates or accelerates the travel of the forklift F, regardless of the operation of the driver H, depending on the threshold value changed by the threshold setting unit 28.

[0055] That is, when the maximum traveling speed changed by the threshold setting unit 28 is slower than the traveling speed before the change, the drive control unit 30 reduces the traveling speed of the forklift F. Furthermore, when the maximum traveling acceleration changed by the threshold setting unit 28 is smaller than the traveling acceleration before the change, the drive control unit 30 reduces the traveling acceleration of the forklift F.

[0056] As a result, when the overhead crane 300 or the movable shelf, which moves left and right, blocks the traveling direction, the drive control unit 30 delays the arrival of the forklift F until the overhead crane 300 or the movable shelf has passed, thereby preventing the loading unit CP from colliding with the overhead crane 300 or the movable shelf. Also, when the shutter 200, which opens and closes up and down, blocks the traveling direction, the drive control unit 30 delays the arrival of the forklift F until the shutter 200 opens to allow the forklift F to pass, thereby preventing the loading unit CP from colliding with the shutter 200.

[0057] When the threshold value of the maximum traveling speed or the maximum traveling acceleration is 0, the stopping unit 32 controls the brake 12 to stop the traveling of the forklift F. As a result, when a collision cannot be avoided by stopping the ascent of the loading unit CP, accelerating the descent, or decelerating the traveling, the stopping unit 32 can prevent the loading unit CP from colliding with the object O by stopping the traveling of the forklift F.

[0058] When the threshold value setting unit 28 changes the threshold value and causes deceleration or stop of travel or deceleration, stop, or acceleration of the lifting and lowering of the loading unit CP, the notification unit 34 causes the speaker 15 to output an alarm sound to that effect. In this way, the notification unit 34 makes the driver H aware that deceleration or stop of travel or deceleration, stop, or acceleration of the lifting and lowering of the forks 5 will occur regardless of the operation of the driver H. Note that, for example, the forklift F may further have a monitor, and the notification unit 34 may make the driver H aware via this monitor that deceleration or stop of travel or deceleration, stop, or acceleration of the lifting and lowering of the forks 5 will occur; the notification method according to the present invention is not particularly limited.

[0059] <Collision prevention system operation> Next, the operation of the collision prevention system S will be described with reference to FIG.

[0060] (1) The collision prevention system S uses the front camera 8 and the rear camera 9 to capture images of the area in front of the loading section CP, the area in front including the loading section CP, and the area above including the loading section CP, and generates first and second images (see S (step) 1 in Figure 6).

[0061] (2) Next, the collision prevention system S estimates a future position OP2 of the object O by the object position estimation unit 22, and estimates a future position LP2 of the loader CP by the loader position estimation unit 24 (see S2 in FIG. 6).

[0062] (3) Next, the collision prevention system S uses the distance estimation unit 26 to estimate the distances D1 and D2 in the horizontal and vertical directions from the future position LP2 of the loader CP to the future position OP2 of the object O (see S3 in FIG. 6).

[0063] (4) Next, the collision prevention system S sets a threshold value for the moving speed of the loading unit CP by the threshold value setting unit 28 so that the loading unit CP does not collide with the object O (see S4 in FIG. 6).

[0064] (5) Next, when the threshold value is changed by the threshold value setting unit 28 and the traveling speed or the lifting speed is changed (Yes in S5 of FIG. 6), the collision prevention system S causes the notification unit to notify of the change (see S6 of FIG. 6). On the other hand, when the threshold value is not changed and the traveling speed or the lifting speed is not changed (No in S5 of FIG. 6), the collision prevention system S does nothing.

[0065] (6) Next, when the threshold values ​​for the traveling speed and the lifting / lowering speed are changed, the collision prevention system S changes the lifting / lowering speed and the traveling speed using the lifting / lowering control unit 29 and the drive control unit 30 (see S7 in FIG. 6). Also, when the threshold value for the traveling speed is set to 0, the collision prevention system S stops traveling using the brake 12.

[0066] <Effects of the present invention> Fig. 7 is a side view showing the effect of the present invention, Fig. 7A shows conventional operation, and Figs. 7B and 7C show operation of the present invention. With the above-described configuration and operation, the collision prevention stem can avoid a collision by reducing the traveling speed in advance as shown in Fig. 7B, or by increasing the descent speed in advance as shown in Fig. 7C, even in cases where a conventional system would have stopped the forklift F by applying brake 12 just before it collided with shutter 200. As a result, the collision prevention stem can prevent a collision while traveling at a relatively stable speed without suddenly stopping the forklift F.

[0067] Furthermore, the collision prevention system automatically predicts a collision based on the first and second images, and also automatically controls the speed of ascent and descent and travel, thereby not only reducing the burden on the driver H, but also preventing collisions with objects O that the driver H cannot properly see or predict.

[0068] While the present invention has been described using a moving object O as an example to facilitate understanding, the collision prevention system can also prevent collisions with fixed objects O within a facility. Therefore, even if the loading and unloading locations are located at high altitudes, the collision prevention system can appropriately recognize high-altitude obstacles and prevent collisions by slowing down or stopping the lifting and lowering operation of the loading unit CP based on the distances D1 and D2 between the future position of the obstacle and the future position LP2 of the loading unit CP. As a result, the collision prevention system S can level out high-altitude work that was previously only possible for experienced drivers, improving work efficiency. The object position estimation unit 22 can also appropriately recognize the position of fixed objects O by performing machine learning in advance using the first and second images.

[0069] Although one embodiment of the collision prevention system of the present invention has been described above, the present invention is not limited to the above embodiment. For example, the collision prevention system of the present invention may be implemented by the following modifications or by combining the following modifications as appropriate.

[0070] There are no particular limitations on the content of the notification by the notification unit 34 via the speaker 15, the monitor, etc. For example, the notification unit 34 may notify, via the speaker 15 or the monitor, that the loading unit CP is approaching the object O, or may notify that a collision will occur if the future position LP2 of the loading unit CP and the future position OP2 of the object O overlap.

[0071] In the above embodiment, the front camera 8 and the rear camera 9 are configured as a stereo camera, with one camera on each side. This makes it easy to measure the distance to the object O in the image from the first and second images generated by these cameras. However, even if the front camera 8 and the rear camera 9 are configured as a single camera, it is possible to measure the distance to the object O in the image and measure the position of the loading unit CP over time using distance measurement technology with a monocular camera. For example, the collision prevention system S may further include a distance measurement device disposed on the forklift F, and may estimate the future position OP2 of the loading unit CP and the object O using this distance measurement device, the first image, and the second image. [Explanation of symbols]

[0072] S Collision prevention system F Forklift CP loading section MD1 Loading unit movement direction MD2 Object movement direction OP1 Current position of the object OP2 Future position of the object LP1 Current position of loading area LP2 Future position of loading area D1: The distance between the future position of the payload and the future position of the object in the horizontal direction D2: The distance between the future position of the payload and the future position of the object in the vertical direction O object 2 wheels 3. Body 4 Mast 5 forks 6 Backrest 7 Head Guard 8 Front camera 9 Rear camera 10 Drive unit 12 Brake 14 Lifting section 15 Speaker 20 Control Unit 22 Object position estimation section 24 Loading section position estimation section 26 Distance estimation unit 28 Threshold setting section 29 Lift control section 30 Drive control unit 32 Stop part 34 Notification Department 100 Conventional forklift 200 Shutter (Object) 201 Shutter body 202 Pillar 300 Ceiling crane (object) 301 Hook 302 Wire 303 Trolley L load

Claims

1. a front camera disposed on the forklift, capturing an image of a front area of ​​a loading section of the forklift to generate a first image; a rear camera disposed on the forklift, capturing an image of both a front side including the loading section and an upper side including the loading section, and generating a second image; an object position estimation unit that has previously undergone machine learning to estimate a future movement position of an object (hereinafter simply referred to as "object") within a facility based on a plurality of consecutive first images including the object and a plurality of consecutive second images including the object, and the times at which the first and second images were captured; a loading unit position estimation unit that has previously performed machine learning to estimate a future movement position of the loading unit for each time period based on a plurality of consecutive first images, a plurality of consecutive second images, and the times at which the first and second images were captured; a distance estimation unit that estimates a distance from the loading unit to the object when the object is placed in the movement direction of the loading unit due to the movement of the object, and a distance between the loading unit and the object that has already been placed in the movement direction of the loading unit; a threshold setting unit that changes a threshold value of the moving speed of the loading unit by referring to the distance estimated by the distance estimation unit so that the loading unit does not collide with the object.

2. The collision prevention system of claim 1 , wherein the threshold value of the load movement speed includes a maximum travel speed and / or a maximum travel acceleration.

3. The collision prevention system of claim 1 , wherein the threshold value of the load unit movement speed includes both or one of a maximum lifting speed of the load unit and a maximum lifting / lowering acceleration of the load unit.

4. The collision prevention system of claim 1 , wherein the payload movement speed threshold comprises a minimum descent speed and / or a minimum descent acceleration.

5. 5. The collision prevention system according to claim 1, wherein the range of the threshold value includes 0, and the system is configured to be able to substantially stop movement of the load unit.

6. The forklift has a brake, The collision prevention system includes: The collision prevention system according to claim 2 , further comprising a stopping unit that controls the brakes to stop the forklift when a threshold value of a maximum traveling speed or a maximum traveling acceleration is zero.

7. The collision prevention system of claim 1 , wherein the object includes a shutter that moves up and down to open and close.

8. The collision avoidance system of claim 1 , wherein the object includes an overhead crane.

9. The collision prevention system of claim 1 , wherein the object includes a moving shelf.

10. The collision prevention system according to claim 1 , wherein the object also includes a wall, a rack, or a ceiling that is fixed within a facility.

11. The collision prevention system according to claim 1 , further comprising a notification unit that, when the threshold value of the moving speed of the load unit is changed and the load unit is decelerated or stopped, notifies the driver of the deceleration or stoppage.

12. A forklift truck comprising the collision prevention system of claim 1.

13. A collision prevention program used in a collision prevention system having a front camera that takes an image of an area in front of a loading section of a forklift and generates a first image, a rear camera that takes an image of an area in front of the loading section and / or an area above the loading section and generates a second image, and a computer, The computer, an object position estimation unit that has previously undergone machine learning to estimate a future time-based movement position of an object (hereinafter simply referred to as "object") within a facility based on a plurality of consecutive first images including the object and a plurality of consecutive second images including the object, and the times at which the first and second images were captured; a loading unit position estimation unit that has previously performed machine learning to estimate a future movement position of the loading unit for each time period based on a plurality of consecutive first images, a plurality of consecutive second images, and the times at which the first and second images were captured; a distance estimation unit that estimates a distance from the loading unit to the object when the object is placed in the movement direction of the loading unit due to the movement of the object, and a distance between the loading unit and the object that has already been placed in the movement direction of the loading unit; A collision prevention program that is executed as a threshold setting unit that changes a threshold value of the movement speed of the loading unit by referring to the movement position of the object and the movement position of the loading unit so that the loading unit does not collide with the object.

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