Forklift and forklift control method

Abstract

When handling cargo, take into account the downward tilt of the cargo bed. [Solution] The forklift according to the present disclosure is a forklift that performs loading and unloading of an object onto the loading platform of a vehicle, and includes forks that are inserted into insertion holes provided in the object, an illumination unit that irradiates a reference light from the side of the loading platform toward the loading surface of the loading platform, an observation unit that observes the reference light irradiated onto the loading platform, an illumination control unit that controls the irradiation of the reference light in accordance with the tilt of the loading platform when the reference light is not irradiated onto the loading platform, and an operation control unit that controls the operation of the forks according to the observation result of the controlled reference light.

Description

Technical Field

[0001] The present disclosure relates to a forklift and a method for controlling a forklift.

Background Art

[0002] Patent Document 1 discloses a cargo handling system that enables an unmanned forklift to pick up a load from a cargo bed even when the ground height of the cargo bed of a truck changes. The cargo handling system described in Patent Document 1 includes a truck having a cargo bed on which a load is stacked and an unmanned forklift for picking up the load. The truck includes an information transmission unit that transmits ground height information related to the ground height of the cargo bed. The unmanned forklift controls the raising and lowering of the forks based on the ground height information when picking up a load with the forks.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the cargo handling system of Patent Document 1, the ground height information of the cargo bed is estimated on the truck side based on load data indicating the load applied to the cargo bed (the loading amount of the load stacked on the cargo bed) and a ground height estimation model, and is transmitted to the unmanned forklift side.

[0005] However, in Patent Document 1, only the height information of the cargo bed is provided from the truck side to the unmanned forklift, and the inclination of the cargo bed caused by the progress of the cargo handling is not considered. When the cargo bed is tilted, the forklift may not be able to insert the forks into the insertion holes of the pallet, and there is a risk that the cargo handling cannot be performed. In particular, in the "front-down state" where the back side of the cargo bed is lowered and the front side is raised as viewed from the forklift side, it becomes difficult to perform cargo handling with the forklift.

[0006] This disclosure was made in view of the above problems and aims to provide a forklift capable of performing cargo handling operations while taking into account the tilt of the cargo bed when it is tilted downwards at the front. [Means for solving the problem]

[0007] The forklift relating to this disclosure is a forklift that performs loading and unloading of an object onto the loading platform of a vehicle, and includes forks that are inserted into insertion holes provided in the object, an illumination unit that emits reference light from the side of the loading platform toward the mounting surface of the loading platform, an observation unit that observes the reference light emitted onto the loading platform, an illumination control unit that controls the emission of the reference light in accordance with the tilt of the loading platform when the reference light is not emitted onto the loading platform, and an operation control unit that controls the movement of the forks according to the observation results of the controlled reference light.

[0008] The forklift control method according to this disclosure is a forklift control method for loading and unloading an object onto the loading platform of a vehicle, and includes the steps of: irradiating a reference light from the side of the loading platform toward the loading surface of the loading platform; observing the reference light irradiated onto the loading platform; if the reference light is not irradiated onto the loading platform, controlling the irradiation of the reference light in accordance with the tilt of the loading platform; and controlling the movement of the forks inserted into insertion holes provided in the object according to the observation result of the controlled reference light. [Effects of the Invention]

[0009] According to this disclosure, it becomes possible to perform cargo handling while taking into account the tilt of the cargo bed when it is in a downward-sloping position. [Brief explanation of the drawing]

[0010] [Figure 1] This is a diagram showing the configuration of a forklift according to Embodiment 1. [Figure 2] This block diagram shows an example of the configuration of the control device shown in Figure 1. [Figure 3]This diagram illustrates the inclination of the truck bed and the region corresponding to the mounting surface of the reference light in Embodiment 1. [Figure 4] This diagram illustrates the inclination of the truck bed and the region corresponding to the mounting surface of the reference light in Embodiment 1. [Figure 5] This diagram illustrates the tilt of the truck bed and the region corresponding to the mounting surface of the reference light in Embodiment 2. [Figure 6] This diagram illustrates the tilt of the truck bed and the region corresponding to the mounting surface of the reference light in Embodiment 2. [Modes for carrying out the invention]

[0011] Embodiments of this disclosure will be described below with reference to the drawings. For clarity of explanation, the following descriptions and drawings have been omitted and simplified as appropriate. In addition, the same elements are denoted by the same reference numerals in each drawing, and redundant explanations have been omitted where necessary.

[0012] The embodiment relates to an unmanned forklift having the function of loading and unloading cargo onto the cargo bed of a freight vehicle such as a truck.

[0013] Embodiment 1. Figure 1 is a diagram showing the configuration of a forklift 10 according to Embodiment 1. Figure 1 shows a view of the forklift 10 from the left side and a view of the truck 30 from the rear. The truck 30 is positioned in front of the forklift 10. The truck 30 is a vehicle that transports objects 40 on which cargo 42 is loaded onto cargo materials 41 such as pallets or skids.

[0014] The forklift 10 performs cargo handling operations, including unloading objects 40 from a truck 30 and loading objects 40 onto a truck 30, for example, in a workplace such as a factory or commercial facility. The cargo material 41 has a storage section (not shown) for accommodating cargo 42 and insertion holes 43 provided on the lower side of the storage section into which the forks 15 of the forklift 10, which will be described later, are inserted. The insertion holes 43 are through holes that penetrate from one end to the other end of the cargo material 41.

[0015] The truck 30 includes a loading platform 31, tires 32, and side walls 33. An object 40 is loaded on the loading platform 31. The surface of the loading platform 31 on which the object 40 is loaded is defined as a placement surface 34. The tires 32 support the load applied to the loading platform 31. The side walls 33 form a cargo compartment 35 for accommodating the object 40. By flipping up the side walls 33, the side of the cargo compartment 35 is released. The forklift 10 can perform the loading and unloading of the object 40 in the cargo compartment 35 from the side of the truck 30 when the cargo compartment 35 is released.

[0016] Since the tires 32 deform according to the weight of the object 40 loaded on the loading platform 31, the ground height of the loading platform 31 (that is, the distance from the ground surface to the placement surface 34) changes. Also, when the object 40 is placed on the loading platform 31, the suspension of the truck 30 sinks. Therefore, depending on the placement position of the object 40 on the loading platform 31, the loading platform 31 may tilt in the front-rear direction with respect to the forklift 10. Hereinafter, the state where the back side is lowered and the front side is raised when viewed from the forklift 10 side of the loading platform 31 is referred to as a "front-lowered state", and the state where the back side is raised and the front side is lowered is referred to as a "front-raised state".

[0017] When the load 41 is placed on the loading platform 31, the direction in which the insertion hole 43 extends changes according to the tilt of the loading platform 31. For example, if the placement surface 34 of the loading platform 31 is horizontal, the direction in which the insertion hole 43 extends is also horizontal.

[0018] The forklift 10 includes a vehicle body 11 and a loading and unloading device 12. The loading and unloading device 12 includes a mast 13, a lift bracket 14, and forks 15. The mast 13 is configured, for example, by an outer mast (not shown) and an inner mast being slidably engaged. The lift bracket 14 is connected to the inner mast of the mast 13, for example. The lift bracket 14 is provided so as to be able to move up and down with respect to the inner mast.

[0019] A fork 15 is attached to the lift bracket 14. The fork 15 extends forward toward the forklift 10. The fork 15 is a part that is inserted into an insertion hole provided in the object 40.

[0020] In addition, the forklift 10 includes a lift cylinder and a tilt cylinder not shown in the figure. The lift cylinder is a fork lifting mechanism that raises and lowers the fork 15, for example, a hydraulic cylinder. By supplying and discharging hydraulic oil to the lift cylinder, the fork 15 moves up and down together with the lift bracket 14. The tilt cylinder is a fork tilting mechanism that tilts the fork 15 in the front-rear direction, for example, a hydraulic cylinder. The fork 15 tilts by supplying and discharging hydraulic oil to the tilt cylinder.

[0021] The forklift 10 further includes a drive mechanism and a hydraulic mechanism not shown in the figure. The drive mechanism is a member for driving the forklift 10. For example, in the case of a forklift where the drive wheels are driven by a travel motor, the drive mechanism may include a travel motor, a motor driver, a steering device, etc.

[0022] The hydraulic mechanism is a member for controlling the supply and discharge of hydraulic oil to the lift cylinder and the tilt cylinder. The hydraulic mechanism includes a cargo handling motor for driving a pump that discharges hydraulic oil, a control valve for distributing hydraulic oil, etc. The control device 1 operates the cargo handling device 12 by controlling the hydraulic mechanism. The forklift 10 is an unmanned forklift that operates automatically under the control of the control device 1.

[0023] The forklift 10 further includes an illumination device 16 and an imaging device 17. The illumination device 16 illuminates a reference light from the side of the loading platform 31 toward the mounting surface 34 of the loading platform 31. The illumination device 16 is fixed to the mast 13, for example. The imaging device 17 is an observation unit that observes the reference light illuminated onto the loading platform 31. In Embodiment 1, the imaging device 17 may be a camera that photographs the area of ​​the mounting surface 34 of the loading platform 31 that is illuminated by the reference light. The imaging device 17 is provided, for example, on the top of the mast 13. The imaging device 17 can output the image of the mounting surface 34 it has captured to the control device 1.

[0024] The forklift 10 includes a control device 1 that controls the operation of each part. Figure 2 is a block diagram showing the configuration of the control device 1 of the forklift 10 according to Embodiment 1. The control device 1 includes a storage unit 2 and a processing unit 3. The storage unit 2 is an example of a storage device that includes non-volatile memory such as flash memory or an SSD (Solid State Drive). The storage unit 2 stores a program that causes a computer to execute each process of the control method for the forklift 10 according to Embodiment 1.

[0025] The processing unit 3 is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or a DSP (Digital Signal Processor). The processing unit 3 loads a program into memory such as RAM (Random Access Memory), which is not shown, and executes it. In this way, the processing unit 3 realizes the functions of the calculation unit 4, the operation control unit 5, and the irradiation control unit 6.

[0026] Furthermore, each component of the control device 1 may be implemented using hardware circuits such as ASICs (Application Specific Integrated Circuits) or FPGAs (Field Programmable Gate Arrays). Also, some or all of the components of each device may be implemented using general-purpose or dedicated circuits, processors, etc., or combinations thereof. These may be configured as a single chip or as multiple chips connected via a bus. Some or all of the components of each device may also be implemented using combinations of the aforementioned circuits, etc., and programs.

[0027] The calculation unit 4 calculates the inclination of the truck bed 31 of the truck 30. Here, the calculation unit 4 calculates the inclination of the truck bed based on the observed reference light. Specifically, the calculation unit 4 acquires an image of the mounting surface 34 input from the imaging device 17. Then, the calculation unit 4 performs known image processing to calculate the length of the area on the mounting surface 34 that is illuminated by the reference light along the direction of illumination. The calculation unit 4 can determine the inclination of the truck bed 31 according to this length. The operation control unit 5 controls the inclination of the forks 15 according to the calculated inclination angle of the truck bed 31.

[0028] Furthermore, if the reference light spreads vertically (up and down), even if the inclination of the loading platform 31 changes, the reference light will hit the entire width of the loading platform 31, and there will be no change in the length of the area hit by the reference light along the direction of illumination, which may prevent accurate calculation of the inclination of the loading platform 31. For this reason, it is preferable that the reference light emitted from the illumination device 16 has a small vertical spread.

[0029] The reference light emitted from the illumination device 16 can be, for example, a spot light or a slit light extending horizontally. The illumination device 16 can convert diffused light emitted from a light source such as an LED into a spot light by passing it through an aperture. The illumination device 16 can also convert diffused light into slit light by passing it through an optical slit. By reducing the vertical spread of the reference light, the length of the illumination area LT along the illumination direction can be changed according to the inclination of the cargo bed 31, making it possible to accurately calculate the inclination of the cargo bed 31.

[0030] When the mounting surface 34 is horizontal, that is, when the inclination angle of the loading platform 31 is 0°, the reference light emitted from the illumination device 16 hits the entire width of the mounting surface 34. In this case, the operation control unit 5 can control the tilt of the forks 15 so that the forks 15 inserted into the insertion holes are horizontal.

[0031] When the loading platform 31 is tilted upwards at the front, the reference light emitted from the illumination device 16 hits a portion of the mounting surface 34 in the width direction. In this case, the length of the illumination area along the direction of the reference light is shorter than the length when the loading platform 31 is horizontal. The calculation unit 4 can determine the tilt angle of the loading platform 31 according to the length of the reference light along the direction of illumination when the loading platform 31 is tilted upwards at the front. The operation control unit 5 can control the tilt of the forks 15 according to the calculated tilt angle of the loading platform 31.

[0032] As described above, if the vertical spread of the reference light is restricted, the reference light emitted from the illumination device 16 will not illuminate the mounting surface 34 if the loading platform 31 is tilted downwards at the front. In this case, the tilt of the loading platform 31 cannot be calculated, and the object 40 cannot be picked up with the forks 15. However, even if the loading platform 31 is tilted downwards at the front, if the tilt of the loading platform 31 is such that the forks 15 can be inserted into the object insertion holes of the object 40, it is possible to pick up the object 40.

[0033] Therefore, in this embodiment, if the reference light is not irradiated onto the cargo bed 31, the irradiation control unit 6 controls the irradiation of the reference light in accordance with the tilt of the cargo bed 31. As an example, the irradiation control unit 6 can change the angle at which the reference light spreads vertically so that the reference light is irradiated onto the cargo bed 31.

[0034] Figures 3 and 4 illustrate the inclination of the truck bed and the region corresponding to the mounting surface of the reference light in Embodiment 1. Figures 3 and 4 show examples where the angle of the vertical spread of the reference light is changed. In Figures 3 and 4, the region on the mounting surface 34 that is illuminated by the reference light is defined as the illumination region LT. In Figures 3 and 4, the illumination region LT, when viewed from above on the mounting surface 34, is shown above the truck bed 31.

[0035] The inclination angle of the cargo bed 31 is defined as the angle between the horizontal plane and the mounting surface 34 when the cargo bed 31 is viewed from the rear. The inclination angle of the cargo bed 31 can be expressed as a positive value if it is tilted upwards at the front, and as a negative value if it is tilted downwards at the front. Similarly, the angle at which the reference light spreads in the vertical direction is expressed as a positive value when it is tilted upwards from the horizontal direction, and as a negative value when it is tilted downwards from the horizontal direction.

[0036] As shown in Figure 3, the irradiation control unit 6 changes the downward angle of the reference light emitted from the irradiation device 16 to a predetermined value (-θ). Here, θ is the maximum absolute value of the angle at which the forks 15 can be inserted into the insertion holes 43 of the object 40 when the loading platform 31 is tilted downwards.

[0037] If the inclination of the loading platform 31 is in the range of 0° (horizontal) to -θ, the reference light emitted from the illumination device 16 will hit the entire width of the mounting surface 34. That is, the length L1 of the illumination area LT along the direction of illumination of the reference light is equal to the width of the mounting surface 34. In this case, even if the loading platform 31 is tilted downwards at the front, the forks 15 can be inserted into the insertion holes of the object 40 without changing the inclination angle of the forks 15.

[0038] The motion control unit 5 controls the movement of the forks according to the observation results of the reference light controlled by the irradiation control unit 6. When the controlled reference light hits the entire width of the mounting surface 34, the motion control unit 5 moves the forklift 10 forward in the direction of the track 30, thereby inserting the forks 15 into the insertion holes of the object 40.

[0039] On the other hand, as shown in Figure 4, if the inclination angle of the loading platform 31 is smaller than the angle at which the reference light emitted from the illumination device 16 spreads downward (<-θ), the reference light will not illuminate the loading surface 34. In this case, the calculation unit 4 can output information to the operation control unit 5 indicating that the reference light will not illuminate the loading surface 34. If the inclination angle of the loading platform 31 is smaller than -θ, the object 40 cannot be picked up by the forks 15. In this case, the operation control unit 5 may, for example, notify the worker that it is impossible to load or unload the object 40 with the forklift 10 using sound, light, etc.

[0040] Furthermore, the control of the reference light irradiation by the irradiation control unit 6 is not limited to controlling the angle at which the reference light spreads. For example, the irradiation control unit 6 may change the irradiation angle of the reference light, which has limited vertical spread, so that the reference light irradiates the cargo bed 31. The irradiation angle is the angle that the irradiation direction of the reference light makes with the horizontal direction. The irradiation control unit 6 can change the irradiation direction of the reference light, which has limited vertical spread, from the horizontal direction to downward.

[0041] For example, it can be seen that when the angle of change of the irradiation direction is in the range of 0° to -θ, and the reference light hits the entire width of the mounting surface 34, the fork 15 can be inserted into the insertion hole of the object 40.

[0042] Furthermore, the forklift 10 may have, in addition to the illumination device that emits a reference light horizontally, an illumination device that emits a reference light downward from the horizontal direction. The illumination control unit 6 may switch from the illumination device that emits a reference light horizontally to the illumination device that emits a reference light downward from the horizontal direction when the loading platform 31 is in a downward-sloping position. For example, the illumination device that emits a reference light downward from the horizontal direction can have the direction of the reference light emission set to the -θ direction.

[0043] As described above, according to this embodiment, the tilt of the forks 15 can be controlled according to the tilt angle of the loading platform 31 using a simple system consisting of an inexpensive illumination device 16 and an imaging device 17. This makes it possible to perform unmanned loading and unloading by the forklift 10 while taking into account the tilt of the loading platform. Furthermore, the forklift 10 can control the illumination of the reference light when the loading platform 31 is tilted downwards at the front and the reference light is not illuminating the loading platform 31. This makes it possible to perform loading and unloading while taking into account the tilt of the loading platform when it is tilted downwards at the front.

[0044] Next, the control method for the forklift of Embodiment 1 will be described. Here, we will describe an example in which the forklift 10 performs unloading work when the loading platform 31 of the truck 30 is in a downward-sloping position as seen from the forklift 10.

[0045] First, the illumination device 16 illuminates the loading surface 34 of the loading platform 31 horizontally with reference light from the side. Then, the imaging device 17 observes the reference light illuminated on the loading platform 31. Specifically, the imaging device 17 photographs the illuminated area LT on the loading surface 34 of the loading platform 31 that is illuminated by the reference light. The imaging device 17 transmits the captured image to the control device 1.

[0046] The control device 1 determines the length of the area on the mounting surface 34 illuminated by the reference light along the illumination direction from the received image, and calculates the tilt of the loading platform 31 according to that length. Here, if the loading platform 31 is tilted downwards, the reference light will not hit the mounting surface 34. In this case, the control device 1 controls the illumination of the reference light according to the tilt of the loading platform. As described above, the control device 1 changes the angle at which the reference light emitted from the illumination device 16 spreads downwards to a predetermined value (-θ). When the reference light hits the entire width of the mounting surface 34, the control device 1 moves the forklift 10 toward the truck 30 without changing the tilt angle of the forks 15, inserts the forks 15 into the insertion holes 43 of the object 40, and makes it possible to unload the object 40 from the truck 30.

[0047] When the forklift 10 performs loading operations, the loading control is performed when the object 40 is loaded onto the forks 15. The state in which the object 40 is loaded onto the forks 15 means that the forks 15 are inserted into the insertion holes of the object 40 and the object 40 is supported by the forks 15. As described above, if the horizontally irradiated reference light does not hit the mounting surface 34, the control device 1 controls the irradiation of the reference light in accordance with the tilt of the loading platform to determine whether or not it hits the entire width of the mounting surface 34.

[0048] When the reference light shines across the entire width of the mounting surface 34, the control device 1 can load the object 40 onto the truck 30 without changing the tilt angle of the forks 15.

[0049] Embodiment 2. The forklift 10 according to Embodiment 2 has a configuration substantially the same as that shown in Figure 1. Both the forks 15 and the illumination device 16 are fixed to the mast 13. A tilt cylinder (not shown) can tilt the mast 13, thereby simultaneously tilting the forks 15 and the illumination device 16. Here, the operation control unit 5 and the illumination control unit 6 in Figure 2 are combined to form the tilt control unit. The tilt control unit can simultaneously change the illumination angle of the reference light and the tilt angle of the forks 15 by tilting the mast 13.

[0050] Here, the irradiation device 16 irradiates a reference light whose spread in the vertical direction is limited. The difference between Embodiment 2 and Embodiment 1 is that the tilt of the fork 15 is controlled in accordance with the change in the irradiation angle of the reference light. As described above, the irradiation angle of the reference light is the angle that the irradiation direction of the reference light makes with the horizontal direction.

[0051] Figures 5 and 6 illustrate the inclination of the truck bed and the region corresponding to the mounting surface of the reference light in Embodiment 2. In Figures 5 and 6, the region on the mounting surface 34 that is illuminated by the reference light is defined as the illumination region LT. In Figures 5 and 6, the illumination region LT, when viewed from above on the mounting surface 34, is shown above the truck bed 31.

[0052] First, the illumination device 16 illuminates the loading surface 34 horizontally from the side of the loading platform 31 with reference light. At this time, the direction in which the forks 15 extend is the same as the direction of illumination of the reference light, which is horizontal. As shown in Figure 5, if the loading platform 31 is sloped downwards at the front, the reference light will not illuminate the loading platform 31.

[0053] The tilt control unit changes the illumination angle of the reference light if the reference light is not illuminating the loading platform 31. Specifically, the tilt control unit changes the illumination angle of the reference light until the length of the area on the loading surface 34 of the loading platform 31 that is illuminated by the reference light, along the direction of illumination, exceeds a predetermined threshold. The tilt control unit can also control the tilt of the forks 15 in accordance with the change in the illumination angle of the reference light. Note that the illumination angle of the reference light and the tilt angle of the forks 15 may be controlled separately.

[0054] As shown in Figure 6, for example, the tilt control unit can control the irradiation angle of the reference light so that the tilt of the loading platform 31 and the irradiation direction of the reference light are approximately parallel. As a result, the reference light hits the entire width of the mounting surface 34, and the length L1 of the irradiation area LT along the irradiation direction of the reference light is equal to the width of the mounting surface 34.

[0055] The tilt angle of the fork 15 is controlled according to the illumination angle of the modified reference light. This allows the direction in which the insertion hole 43 extends to approximately coincide with the direction in which the fork 15 extends, making it possible to insert the fork 15 into the insertion hole.

[0056] If the absolute value of the inclination angle of the fork 15 is greater than a predetermined angle, the fork 15 may come into contact with the ceiling of the insertion hole 43 while it is entering the insertion hole 43. In this case, the control device 1 may lower the fork 15 while it is entering the insertion hole 43.

[0057] Next, the control method for the forklift 10 of Embodiment 2 will be described. Here, we will describe an example in which the forklift 10 performs unloading work when the loading platform 31 of the truck 30 is in a downward-sloping position as seen from the forklift 10.

[0058] First, the illumination device 16 illuminates the loading surface 34 from the side of the loading platform 31 with reference light horizontally. The reference light is light with limited vertical spread. The imaging device 17 observes the reference light illuminated on the loading platform 31. If the loading platform 31 is tilted downwards, the reference light does not hit the loading surface 34. In this case, the control device 1 controls the illumination angle of the reference light so that it illuminates the loading platform 31. At this time, the control device 1 changes the illumination angle of the reference light until the length of the area on the loading surface 34 of the loading platform 31 that is illuminated by the reference light, along the illumination direction, is greater than or equal to a predetermined threshold. The control device 1 also controls the tilt of the forks 15 according to the changed illumination angle of the reference light.

[0059] For example, the tilt control unit can control the irradiation angle of the reference light so that the tilt of the loading platform 31 and the irradiation direction of the reference light are approximately parallel. As a result, the reference light hits the entire width of the mounting surface 34, and the length L1 of the irradiation area LT along the irradiation direction of the reference light is equal to the width of the mounting surface 34. At this time, the tilt angle of the forks 15 is controlled according to the changed irradiation angle of the reference light. This makes it possible to approximately coincide the direction in which the insertion holes 43 extend with the direction in which the forks 15 extend. The control device 1 can move the forklift 10 toward the truck 30, insert the forks 15 into the insertion holes 43 of the object 40, and unload the object 40 from the truck 30.

[0060] When the forklift 10 performs loading operations, the loading control is performed with the object 40 loaded onto the forks 15. As described above, if the horizontally irradiated reference light does not hit the loading surface 34, the control device 1 controls the irradiation angle of the reference light in accordance with the inclination of the loading platform, and also controls the tilt angle of the forks 15. The control device 1 controls the irradiation angle of the reference light and also controls the tilt angle of the forks 15 until the length along the irradiation direction of the area irradiated by the reference light exceeds a predetermined threshold, for example, until the reference light hits the entire width of the loading surface 34. When the reference light hits the entire width of the loading surface 34, the forklift 10 can load the object 40 onto the truck 30.

[0061] As described above, according to the embodiment, the forklift 10 can automatically perform cargo handling operations while taking into account the tilt of the loading platform 31 that occurs as the cargo handling progresses. Furthermore, even when the loading platform 31 is tilted downwards at the front, cargo handling can be performed while taking into account the tilt of the loading platform.

[0062] In the examples described above, the program includes a set of instructions (or software code) that, when loaded into a computer, cause the computer to perform one or more of the functions described in the embodiments. The program may be stored on a non-temporary computer-readable medium or a physical storage medium. Examples, but not limited to, include RAM, read-only memory (ROM), flash memory, SSD or other memory technologies, CD-ROM, digital versatile disc (DVD), Blu-ray® disc or other optical disc storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices. The program may be transmitted over a temporary computer-readable medium or a communication medium. Examples, but not limited to, include, a temporary computer-readable medium or a communication medium that includes an electrical, optical, acoustic or other form of propagating signal.

[0063] Although the present disclosure has been described above with reference to embodiments, the present disclosure is not limited to the embodiments described above. Various modifications to the structure and details of the present disclosure can be made as can be understood by those skilled in the art within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate. [Explanation of Symbols]

[0064] 1 Control device 2 Storage section 3 Processing Unit 4. Calculation Unit 5. Operation Control Unit 6. Irradiation control unit 10 Forklifts 11 Car body 12. Cargo handling equipment 13 Mast 14 Lift Bracket 15 Forks 16 Irradiation device 17 Imaging device 18 Tilt Sensor 18A 1st ranging section 18B 2nd ranging section 30 tracks 31 Cargo bed 32 tires 33 Side wall 34 Mounting surface 35 Cargo area 36 Side view 40 Objects 41 Packing materials 42 loads 43 Insertion hole LT irradiation area

Claims

1. A forklift used for loading and unloading objects onto the loading platform of a vehicle, A fork inserted into an insertion hole provided in the object, An illumination unit that irradiates a reference light from the side of the cargo bed toward the mounting surface of the cargo bed, An observation unit for observing the reference light irradiated onto the cargo bed, If the reference light is not irradiated onto the cargo bed, the irradiation control unit controls the irradiation of the reference light in accordance with the tilt of the cargo bed, An operation control unit controls the movement of the fork according to the observation results of the controlled reference light, including, forklift.

2. The irradiation control unit changes the angle at which the reference light spreads vertically so that the reference light is irradiated onto the cargo bed. The forklift according to claim 1.

3. The aforementioned reference light is light whose spread in the vertical direction is limited. The irradiation control unit changes the irradiation angle of the reference light so that the reference light is irradiated onto the cargo bed. The forklift according to claim 1.

4. The irradiation control unit changes the irradiation angle of the reference light until the length of the area on the loading surface of the cargo bed that is illuminated by the reference light, along the irradiation direction, exceeds a predetermined threshold. The operation control unit controls the tilt of the fork according to the changed irradiation angle of the reference light. The forklift according to claim 3.

5. A control method for a forklift that performs loading and unloading of objects onto the loading platform of a vehicle, The steps include: irradiating a reference light from the side of the cargo bed toward the mounting surface of the cargo bed; The steps include observing the reference light irradiated onto the cargo bed, If the reference light is not irradiated onto the cargo bed, the step of controlling the irradiation of the reference light in accordance with the tilt of the cargo bed, The steps include controlling the movement of a fork inserted into an insertion hole provided in the object, in accordance with the observation results of the controlled reference light, including, Forklift control methods.

Images