WO2022130896A1

WO2022130896A1 - Forklift

Info

Publication number: WO2022130896A1
Application number: PCT/JP2021/042571
Authority: WO
Inventors: 安立結香子
Original assignee: 株式会社豊田自動織機
Priority date: 2020-12-15
Filing date: 2021-11-19
Publication date: 2022-06-23
Also published as: JP7435432B2; JP2022094746A

Abstract

A forklift (10) is provided with a cargo handling device (21), an operation unit (34), and a control device (61). The cargo handling device (21) is provided with a fork (26). The cargo handling device (21) performs cargo handling motions. The cargo handling motions include a lift motion for raising and lowering the fork (26), a tilt motion for tilting the fork, and a reach motion for moving the fork in a front/rear direction. The control device (61) causes the cargo handling device (21) to perform the cargo handling motions in accordance with operation of the operation unit (34). The control device (61) provides assistance to an operator by controlling the cargo handling device (21) such that positioning displacement, by the operator, of the fork (26) and a cargo to be handled becomes small. When the operation unit (34) is operated, the control device (61) prohibits assistance for the cargo handling motion identical to the cargo handling motion performed by the cargo handling device (21) through operation of the operation unit (34).

Description

forklift

This disclosure relates to forklifts.

The forklift disclosed in Patent Document 1 includes a cargo handling device and an operation unit. The cargo handling device performs a cargo handling operation. The cargo handling device is equipped with a fork. The operation unit is operated by an operator who operates the forklift. By operating the operation unit, the vertical position of the fork and the inclination of the fork can be adjusted. When performing loading work or loading work, the operator operates the operation unit to align the fork and the cargo handling target. After aligning the fork and the cargo handling target, the fork is brought closer to the cargo handling target to perform loading and unloading work.

JP-A-2017-114674A

Even when the operator aligns the fork with the cargo handling target, there may be a gap between the fork and the cargo handling target. The forklift may have an auxiliary function that controls the misalignment by the operator so as to be small. However, this auxiliary function may limit the operation of the operator. For example, when the operator adjusts the fork and the cargo handling target by operating the operation unit, the control device may stop the fork at a position where the fork and the cargo handling target do not deviate from each other. .. In this case, the control device stops the fork even though the operator is operating the operation unit. Therefore, the operability of the forklift may be deteriorated.

A forklift that solves the above problems includes a cargo handling device having a fork, a control device configured to cause the cargo handling device to perform a cargo handling operation including at least one of a tilt operation, a lift operation, and a side shift operation, and the above-mentioned. The control device includes an operation unit that is operated when the cargo handling device is to perform a cargo handling operation, and an acquisition unit that acquires information indicating whether or not the operation unit operated by the operator is being operated. Controls the cargo handling device so as to reduce the misalignment between the fork and the cargo handling target by the operator, whereby the auxiliary control for assisting the operator and the operation unit are operated. If so, the operation of the operation unit is characterized in that the prohibition control for prohibiting the auxiliary control for the same cargo handling operation as the cargo handling operation performed by the cargo handling device is performed.

When a cargo handling operation is performed by the operation of the operation unit, auxiliary control for the same cargo handling operation as the cargo handling operation is prohibited. Therefore, when the operator is operating the operation unit, it is possible to prevent the cargo handling operation by the operation unit from being restricted by the auxiliary control. Since the operation of the operator is not restricted by the control device, the discomfort of the operator can be reduced and the deterioration of the operability of the forklift can be suppressed.

With respect to the forklift, the cargo handling operation includes the lift operation, the operation unit includes a lift operation unit corresponding to the lift operation, and the auxiliary control is relative to the vertical direction of the fork and the cargo handling target. The prohibition control includes the lift assist control configured to assist the operator so as to reduce the misalignment, and the prohibition control is the lift when the lift operation is performed by the operation of the lift operation unit. It may include a lift prohibition control that prohibits auxiliary control.

For the forklift, the cargo handling operation includes the tilt operation, the operation unit includes a tilt operation unit corresponding to the tilt operation, and the auxiliary control is relative to the fork and the cargo handling target in the front-rear direction. The prohibition control includes a tilt assist control configured to assist the operator so that the deviation of the tilt is small, and the prohibition control is the tilt operation when the tilt operation is performed by the operation of the tilt operation unit. It may include a tilt prohibition control that prohibits the tilt auxiliary control.

Regarding the forklift, the cargo handling operation includes the side shift operation, the operation unit includes a side shift operation unit corresponding to the side shift operation, and the auxiliary control is a left-right direction between the fork and the cargo handling target. The prohibition control includes the side shift assist control configured to assist the operator so that the relative positional deviation with respect to the vehicle is small, and the prohibition control is performed by the operation of the side shift operation unit. If so, the side shift prohibition control that prohibits the side shift auxiliary control may be included.

Regarding the forklift, the auxiliary control may be performed in the process of the fork approaching the cargo handling target.
At the stage of bringing the fork closer to the cargo handling target, it is assumed that the operator has finished aligning the fork with the cargo handling target. The auxiliary control reduces the deviation caused by this alignment after the operator has finished aligning the fork with the cargo handling target. It is possible to suppress the auxiliary control from being performed even though the alignment has not been completed.

According to the present invention, deterioration of operability can be suppressed.

Side view of the forklift. Perspective view of a forklift. The schematic block diagram of the forklift in 1st Embodiment. The flowchart which shows the lift assist control performed by a control device. A flowchart showing tilt assist control performed by the control device. The figure for demonstrating the operation of the lift assist control. The figure for demonstrating the operation of the lift assist control. The figure for demonstrating the action of the tilt assist control. The figure for demonstrating the action of the tilt assist control. The perspective view which shows the side shift device. The schematic block diagram of the forklift in the 2nd Embodiment. The flowchart which shows the side shift auxiliary control performed by a control device. The figure for demonstrating the operation of the side shift auxiliary control. The figure for demonstrating the operation of the side shift auxiliary control.

(First Embodiment)
The first embodiment of the forklift will be described.
As shown in FIGS. 1 and 2, the forklift 10 includes a vehicle body 11, a reach leg 12, front wheels 13, rear wheels 14, a cargo handling device 21, and an operation unit 34.

The forklift 10 of the present embodiment is a reach type forklift. The forklift 10 may be a counter type forklift. The forklift 10 may be manually operated by an operator boarding the forklift 10, or may be capable of switching between automatic operation and manual operation. That is, the forklift 10 may be any as long as it can be manually operated by the operator. In the following description, the front-back, left-right, up-down are front-back, left-right, up-down with respect to the forklift 10. The front-rear direction can be said to be the traveling direction of the forklift 10. The left-right direction can be said to be the vehicle width direction of the forklift 10. It can be said that the vertical direction is the height direction of the forklift 10.

Two reach legs 12 are provided so as to be separated from each other in the left-right direction. The reach leg 12 extends forward from the vehicle body 11.
One front wheel 13 is provided for each reach leg 12. The rear wheel 14 is provided on the vehicle body 11. The rear wheel 14 is a steering wheel. The rear wheel 14 is a drive wheel.

The cargo handling device 21 is provided in front of the vehicle body 11. The cargo handling device 21 includes a mast 22, a lift bracket 25, a fork 26, a lift cylinder 31, a tilt cylinder 32, and a reach cylinder 33.

The mast 22 is a multi-stage mast. The mast 22 includes an outer mast 23 and an inner mast 24. The inner mast 24 is provided so as to be able to move up and down with respect to the outer mast 23.

The lift bracket 25 is fixed to the inner mast 24. The fork 26 is fixed to the lift bracket 25. Two forks 26 are provided so as to be separated from each other in the left-right direction. The lift bracket 25 is a member for fixing the fork 26 to the inner mast 24.

The lift cylinder 31 is a hydraulic cylinder. The lift bracket 25 moves up and down by supplying and discharging hydraulic oil to and from the lift cylinder 31. The fork 26 moves up and down together with the lift bracket 25.

The tilt cylinder 32 is a hydraulic cylinder. The lift bracket 25 tilts in the front-rear direction by supplying and discharging hydraulic oil to the tilt cylinder 32. Tilt includes forward tilt that tilts the lift bracket 25 forward and backward tilt that tilts the lift bracket 25 backward. The fork 26 tilts together with the lift bracket 25.

The reach cylinder 33 is a hydraulic cylinder. The mast 22 moves in the front-rear direction by supplying and discharging hydraulic oil to the reach cylinder 33. The fork 26 moves in the front-rear direction together with the mast 22. Hereinafter, moving the fork 26 forward by the reach cylinder 33 is referred to as a reach-out operation.

The operation unit 34 includes a lift operation unit 35, a tilt operation unit 36, and a reach operation unit 37.
The lift operation unit 35 is operated by an operator. The lift operation unit 35 of this embodiment is a lever. The lift operation unit 35 tilts forward or backward from the neutral position. The lift operation unit 35 is operated by an operator when raising and lowering the fork 26.

The tilt operation unit 36 is operated by an operator. The tilt operation unit 36 of this embodiment is a lever. The tilt operation unit 36 tilts forward or backward from the neutral position. The tilt operation unit 36 is operated by an operator when the fork 26 is tilted.

The reach operation unit 37 is operated by an operator. The reach operation unit 37 of this embodiment is a lever. The reach operation unit 37 tilts forward or backward from the neutral position. The reach operation unit 37 is operated by an operator when the fork 26 is moved in the front-rear direction.

As shown in FIG. 3, the forklift 10 includes a lift sensor 41, a tilt sensor 42, a reach sensor 43, a drive mechanism 44, a hydraulic mechanism 45, a detection unit 46, a camera 51, and an image processing device 52. , And a control device 61.

The lift sensor 41 detects the amount of operation of the lift operation unit 35. The lift sensor 41 outputs an electric signal according to the amount of operation of the lift operation unit 35. If the operation amount of the lift operation unit 35 is detected by the lift sensor 41, it can be said that the lift operation unit 35 is being operated. If the operation amount of the lift operation unit 35 is not detected by the lift sensor 41, it can be said that the lift operation unit 35 is not operated. The detection result of the lift sensor 41 can be said to be information indicating whether or not the lift operation unit 35 is operated.

The tilt sensor 42 detects the amount of operation of the tilt operation unit 36. The tilt sensor 42 outputs an electric signal according to the amount of operation of the tilt operation unit 36. If the operation amount of the tilt operation unit 36 is detected by the tilt sensor 42, it can be said that the tilt operation unit 36 is being operated. If the operation amount of the tilt operation unit 36 is not detected by the tilt sensor 42, it can be said that the tilt operation unit 36 is not operated. The detection result of the tilt sensor 42 can be said to be information indicating whether or not the tilt operation unit 36 is operated.

The reach sensor 43 detects the amount of operation of the reach operation unit 37. The reach sensor 43 outputs an electric signal according to the amount of operation of the reach operation unit 37. If the amount of operation of the reach operation unit 37 is detected by the reach sensor 43, it can be said that the reach operation unit 37 is being operated. If the operation amount of the reach operation unit 37 is not detected by the reach sensor 43, it can be said that the reach operation unit 37 is not operated. The detection result of the reach sensor 43 can be said to be information indicating whether or not the reach operation unit 37 is operated.

The drive mechanism 44 is a member for driving the forklift 10. The drive mechanism 44 includes a drive source for driving the rear wheels 14 and a steering mechanism for steering the rear wheels 14. In the case of a forklift whose motor is a drive source, the drive mechanism 44 includes a motor driver. In the case of a forklift whose engine is a drive source, the drive mechanism 44 includes a fuel injection device.

The hydraulic mechanism 45 is a member for controlling the supply and discharge of hydraulic oil to the hydraulic equipment. Hydraulic equipment includes a lift cylinder 31, a tilt cylinder 32, and a reach cylinder 33. The hydraulic mechanism 45 includes a pump for discharging hydraulic oil and a control valve for controlling the supply and discharge of hydraulic oil to hydraulic equipment.

The detection unit 46 is provided to detect the position and inclination of the fork 26. The detection unit 46 includes a tilt angle sensor 47, a lift sensor 48, and a reach amount sensor 49.
The tilt angle sensor 47 detects the tilt angle. The tilt angle is the tilt angle of the fork 26. The tilt angle of the fork 26 is, for example, an angle when the state in which the fork 26 is not tilted is 0 °. The tilt angle sensor 47 outputs an electric signal corresponding to the tilt angle to the control device 61. The control device 61 can recognize the tilt angle by the electric signal from the tilt angle sensor 47.

The lift sensor 48 detects the lift. The lift is the height from the road surface to the fork 26. The lift sensor 48 outputs an electric signal corresponding to the lift to the control device 61. The control device 61 can recognize the lift by the electric signal from the lift sensor 48.

The reach amount sensor 49 detects the reach amount. The reach amount is the amount of advance of the fork 26 when the state in which the fork 26 is closest to the vehicle body 11 is set to 0. That is, the reach amount is the distance at which the fork 26 is advanced by the reach-out operation. The reach amount sensor 49 outputs an electric signal according to the reach amount to the control device 61. The control device 61 can recognize the reach amount by the electric signal from the reach amount sensor 49.

The camera 51 is an RGB camera. The camera 51 includes an image pickup element such as a CCD image sensor or a CMOS image sensor. The camera 51 outputs image data composed of three color signals of red, green, and blue.

The camera 51 is attached to a position where it moves up and down together with the fork 26 and tilts together with the fork 26. In this embodiment, the camera 51 is attached to the lift bracket 25. The position of the camera 51 in the left-right direction is, for example, the center position between the two forks 26.

The camera 51 is arranged facing forward. The camera 51 is arranged so that the front of the fork 26 is reflected in the imaging range. The imaging range is determined by the horizontal angle of view and the vertical angle of view of the camera 51.

The image processing device 52 includes a processor 53 and a storage unit 54. As the processor 53, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or a DSP (Digital Signal Processor) is used. The storage unit 54 includes a RAM (Random access memory) and a ROM (Read Only Memory). The storage unit 54 stores a program code or a command configured to cause a processor to execute a process. The storage 54, i.e., a computer-readable medium, includes any available medium accessible by a general purpose or dedicated computer. The image processing device 52 may be configured by a hardware circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The image processing apparatus 52, which is a processing circuit, may include one or more processors operating according to a computer program, one or more hardware circuits such as ASICs and FPGAs, or a combination thereof.

The image processing device 52 detects the position of the cargo handling target and the inclination of the cargo handling target from the image data obtained by the image pickup of the camera 51. The cargo handling target includes a pallet loaded on the fork 26 and a loading space on which the pallet is placed.

The image processing device 52 derives the coordinates and inclination of the cargo handling target in the camera coordinate system from the image data. Let the coordinates of the camera coordinate system be the camera coordinates. The method for deriving the camera coordinates of the cargo handling target is arbitrary.

The image processing device 52 may derive the camera coordinates and inclination of the cargo handling target from the appearance of the cargo handling target in the image data. Since there is a correlation between the relative position of the camera 51 and the cargo handling target and the way the cargo handling target is captured, the camera coordinates and tilt of the cargo handling target may be derived using this correlation.

The image processing device 52 may derive the camera coordinates and inclination of the cargo handling target by using the AR (Augmented Reality) marker. When the AR marker is provided on the cargo handling target, the camera coordinates of the AR marker can be derived by capturing the image of the AR marker by the camera 51. The image processing device 52 may regard the coordinates of the AR marker as the coordinates of the palette, or may derive the camera coordinates of the cargo handling target from the positional relationship between the AR marker and the cargo handling target.

The image processing device 52 may derive the camera coordinates and the inclination from the changes in the position and posture of the camera 51 with time. In this case, the forklift 10 includes a sensor that detects the position and orientation of the camera 51. The image processing device 52 acquires the position and orientation of the camera 51 at the first time and the second time, which are two different times, from the sensor. The image processing device 52 derives changes in the position and orientation of the camera 51 at the first time and the second time. The image processing device 52 determines the change in the coordinates on the image of the same feature point reflected in the image at the first time and the second time, and the change in the position and posture of the camera 51 at the first time and the second time. The camera coordinates of the feature points are derived by triangulation. That is, the image processing device 52 regards the camera 51 at the first time and the camera 51 at the second time as one stereo camera, and derives the camera coordinates. A feature point is a part that can be recognized as a boundary of a cargo handling target, such as an edge of a cargo handling target. Examples of the feature point extraction algorithm include SIFT (Scale-Invariant Feature Transform) and SURF (Speeded Up Robust Features). The image processing device 52 derives the camera coordinates and the inclination of the cargo handling target from the camera coordinates of the feature points.

When the image processing device 52 derives the camera coordinates of the cargo handling target, the image processing device 52 converts the camera coordinates into the coordinates of the world coordinate system. The world coordinate system is a 3-axis Cartesian coordinate system. The X-axis of the world coordinate system is an axis extending in the left-right direction. The Y axis of the world coordinate system is an axis extending in the front-back direction. The Z axis of the world coordinate system is an axis extending in the vertical direction. The origin of the world coordinate system may be any longer as long as the positional relationship with the forklift 10 is constant, and for example, the origin can be the center position between the two front wheels 13. Let the coordinates of the world coordinate system be the world coordinates. The image processing device 52 converts the camera coordinates into world coordinates based on the deviation between the origin of the world coordinate system and the origin of the camera coordinate system and the deviation between the coordinate axes of the world coordinate system and the coordinate axes of the camera coordinate system. The origin of the camera coordinate system and the inclination of the coordinate axes change depending on the position and inclination of the lift bracket 25. Therefore, the image processing device 52 acquires the tilt angle, the lift, and the reach amount from the control device 61, and converts the camera coordinates into the world coordinates based on the acquisition. As a result, the image processing device 52 can derive the world coordinates and the inclination of the cargo handling target. The inclination of the cargo handling target is the deviation angle of the cargo handling target with respect to the coordinate axes of the world coordinate system. In FIG. 2, the X-axis of the world coordinate system is indicated by an arrow X, the Y-axis is indicated by an arrow Y, and the Z-axis is indicated by an arrow Z. In the following description, the X coordinate is the X coordinate in the world coordinate system, and the Z coordinate is the Z coordinate in the world coordinate system.

As shown in FIG. 3, the control device 61 includes a processor 62 and a storage unit 63. The hardware configuration of the control device 61 is, for example, the same as that of the image processing device 52.
The control device 61 controls the traveling operation. The control device 61 drives the forklift 10 by controlling the drive mechanism 44.

The control device 61 controls the cargo handling operation. The control device 61 controls the hydraulic mechanism 45 to cause the cargo handling device 21 to perform a cargo handling operation. The control device 61 acquires the detection results of the lift sensor 41, the tilt sensor 42, and the reach sensor 43. The control device 61 causes the cargo handling device 21 to perform cargo handling operations according to the detection results of the lift sensor 41, the tilt sensor 42, and the reach sensor 43. As a result, the control device 61 can cause the cargo handling device 21 to perform a cargo handling operation according to the operation of the operator. Whether or not each of the lift operation unit 35, the tilt operation unit 36, and the reach operation unit 37 is operated by the control device 61 by acquiring the detection results of the tilt sensor 42, the lift sensor 41, and the reach sensor 43. Can be determined. It can be said that the control device 61 functions as an acquisition unit. The cargo handling operation of the present embodiment includes a lift operation for raising and lowering the fork 26, a tilt operation for tilting the fork 26, and a reach operation for moving the fork 26 in the front-rear direction. The lift operation unit 35 corresponds to the lift operation. The tilt operation unit 36 corresponds to the tilt operation. The reach operation unit 37 corresponds to the reach operation.

When performing cargo handling work with the forklift 10, the operator aligns the fork 26 with the cargo handling target. Cargo handling work includes loading work and unloading work. The loading operation is to place the pallet loaded on the fork 26 in the loading area. The loading operation is to load the pallets placed in the loading area on the fork 26.

When aligning the fork 26 and the cargo handling target, the operator operates the lift operation unit 35 to align the fork 26 and the cargo handling target in the vertical direction. The operator operates the tilt operation unit 36 to adjust the inclination of the fork 26 and the cargo handling target. By operating the reach operation unit 37 in this state to bring the fork 26 closer to the cargo handling target, the loading operation or the loading operation is performed. Taking pallet loading as an example, the operator adjusts the vertical position of the fork 26 and the pallet insertion hole and the inclination of the fork 26 and the pallet, and then inserts the fork 26 into the insertion hole. I will plug it in.

The control device 61 assists the operator in operating the forklift 10 by performing auxiliary control. The auxiliary control is a control that automatically reduces the misalignment between the fork 26 and the cargo handling target by the operation of the operator. Auxiliary control includes lift assist control that assists lift operation and tilt assist control that assists tilt operation. Hereinafter, as an example, an auxiliary control for loading a pallet on the fork 26 will be described. The timing at which the auxiliary control is performed is arbitrary. For example, when the forklift 10 is in the activated state, the auxiliary control may be always performed, or the auxiliary control may be performed when a predetermined condition is satisfied. The predetermined condition is, for example, that the cargo handling operation is started.

Hereinafter, the lift assist control will be described.
The lift assist control is started, for example, on condition that the lift operation is started. The control device 61 starts the lift operation if the operation amount of the lift operation unit 35 is detected by the lift sensor 41. The control device 61 starts lift assist control accordingly. The lift assist control is repeatedly performed in a predetermined control cycle.

As shown in FIG. 4, in step S1, the control device 61 acquires the world coordinates of the pallet. The world coordinates of the palette can be obtained from the image processing device 52.
Next, in step S2, the control device 61 determines whether or not the position of the fork 26 and the pallet is displaced. In the lift assist control, the misalignment between the fork 26 and the pallet is the relative misalignment between the fork 26 and the pallet in the vertical direction. More specifically, the relative positional deviation between the fork 26 and the pallet in the vertical direction is the vertical deviation between the vertical center position of the fork 26 and the vertical center position in the insertion hole of the pallet. be. When the fork 26 is moved toward the pallet by the reach operation, it can be said that the state in which the fork 26 is inserted into the insertion hole is a state in which the position shift does not occur.

Whether or not the position of the fork 26 and the pallet is misaligned can be determined based on the world coordinates of the fork 26 and the world coordinates of the pallet. The positional relationship between the origin of the world coordinate system and the fork 26 is determined by the lift, tilt angle, and reach amount. Therefore, the control device 61 can derive the world coordinates of the fork 26 from the lift, tilt angle, and reach amount. The control device 61 regards the difference between the Z coordinate of the fork 26 and the Z coordinate of the insertion hole of the pallet as the amount of misalignment between the fork 26 and the pallet. If the amount of misalignment between the fork 26 and the pallet is less than the threshold value, the control device 61 determines that no misalignment has occurred. If the amount of misalignment between the fork 26 and the pallet is equal to or greater than the threshold value, the control device 61 determines that the misalignment has occurred. If the determination result in step S2 is negative, the control device 61 ends the lift assist control. If the determination result in step S2 is affirmative, the control device 61 performs the process of step S3.

In step S3, the control device 61 determines whether or not the lift is in operation. In other words, the control device 61 determines whether or not the lift operation has been stopped. If the operation amount of the lift operation unit 35 is detected by the lift sensor 41, the control device 61 determines that the lift operation is in progress. The control device 61 determines that the lift operation is not in progress unless the operation amount of the lift operation unit 35 is detected by the lift sensor 41. If the determination result in step S3 is affirmative, the control device 61 performs the process of step S11. If the determination result in step S3 is negative, the control device 61 performs the process of step S4.

In step S4, the control device 61 determines whether or not to start the reach-out operation. If the reach-out operation is instructed by the reach operation unit 37, the control device 61 starts the reach-out operation. If the determination result in step S4 is negative, the control device 61 ends the lift assist control. If the determination result in step S4 is affirmative, the control device 61 performs the process of step S5.

In step S5, the control device 61 performs lift assist control to assist the lift operation. The lift assist control is to control the cargo handling device 21 so that the control device 61 reduces the relative positional deviation between the fork 26 and the pallet in the vertical direction. The control device 61 controls so as to reduce the misalignment during the reach-out operation. During the reach-out operation, the fork 26 approaches the pallet. It can be said that the control device 61 performs lift assist control in the process of the fork 26 approaching the pallet. The control device 61 raises and lowers the fork 26 by controlling the hydraulic mechanism 45. For example, the control device 61 raises and lowers the fork 26 so that the amount of misalignment between the fork 26 and the pallet is less than the threshold value. When the amount of misalignment between the fork 26 and the pallet becomes less than the threshold value, the control device 61 stops the fork 26 from moving up and down. By performing the process of step S5, it can be said that the control device 61 includes an auxiliary unit for performing auxiliary control and a lift auxiliary unit for performing lift auxiliary control.

In step S11, the control device 61 performs lift prohibition control for prohibiting lift auxiliary control. That is, during the lift operation, it is prohibited to assist the control device 61 so as to reduce the positional deviation between the fork 26 and the pallet. In the lift assist control, when the amount of misalignment between the fork 26 and the pallet becomes less than the threshold value, the fork 26 stops moving up and down. By prohibiting the lift assist control, it is suppressed that the fork 26 is automatically stopped during the lift operation. By performing the process of step S11, it can be said that the control device 61 includes a prohibition unit for performing prohibition control and a lift prohibition unit for performing lift prohibition control.

Hereinafter, tilt assist control will be described.
The tilt assist control is started, for example, on condition that the tilt operation is started. The control device 61 starts the tilt operation if the operation amount of the tilt operation unit 36 is detected by the tilt sensor 42. The control device 61 starts tilt assist control accordingly. The tilt assist control is repeatedly performed in a predetermined control cycle.

As shown in FIG. 5, in step S21, the control device 61 acquires the inclination of the pallet. The tilt of the palette can be obtained from the image processing device 52.
Next, in step S22, the control device 61 determines whether or not the inclination of the fork 26 and the pallet is displaced. The deviation of the inclination between the fork 26 and the pallet is the deviation of the inclination of the fork 26 and the pallet relative to the front-rear direction.

Whether or not the inclination of the fork 26 and the pallet is misaligned can be determined based on the inclination of the fork 26 and the inclination of the pallet. The inclination of the fork 26 is a tilt angle. The slope of the palette is the slope of the palette with respect to the Y axis of the world coordinate system. Since the tilt angle represents the inclination of the world coordinate system with respect to the Y axis, the difference between the tilt angle and the inclination of the pallet with respect to the Y axis of the world coordinate system is the deviation of the relative inclination of the fork 26 and the pallet in the front-back direction. I can say. The control device 61 regards the difference between the inclination of the fork 26 and the inclination of the pallet as the amount of angular deviation between the fork 26 and the pallet. The control device 61 determines that the inclination deviation has not occurred if the angle deviation amount between the fork 26 and the pallet is less than the threshold value. If the angle deviation amount between the fork 26 and the pallet is equal to or greater than the threshold value, the control device 61 determines that the inclination deviation has occurred. If the determination result in step S22 is negative, the control device 61 ends the tilt assist control. If the determination result in step S22 is affirmative, the control device 61 performs the process of step S23.

In step S23, the control device 61 determines whether or not the tilt operation is in progress. In other words, the control device 61 determines whether or not the tilt operation has been stopped. If the operation amount of the tilt operation unit 36 is detected by the tilt sensor 42, the control device 61 determines that the tilt operation is in progress. The control device 61 determines that the tilt operation is not in progress unless the operation amount of the tilt operation unit 36 is detected by the tilt sensor 42. If the determination result in step S23 is affirmative, the control device 61 performs the process of step S31. If the determination result in step S23 is negative, the control device 61 performs the process of step S24.

Step S24 is the same process as step S4. If the determination result in step S24 is negative, the control device 61 ends the tilt assist control. If the determination result in step S24 is affirmative, the control device 61 performs the process of step S25.

In step S25, the control device 61 performs tilt assist control to assist the tilt operation. The tilt assist control is to control the cargo handling device 21 so that the control device 61 reduces the deviation of the inclination between the fork 26 and the pallet. The control device 61 controls so as to reduce the deviation of the inclination during the reach-out operation. During the reach-out operation, the fork 26 approaches the pallet. It can be said that the control device 61 performs tilt assist control in the process of the fork 26 approaching the pallet. The control device 61 tilts the fork 26 by controlling the hydraulic mechanism 45. As a result, the control device 61 reduces the deviation of the inclination between the fork 26 and the pallet. For example, the control device 61 tilts the fork 26 so that the amount of angular deviation between the fork 26 and the pallet is less than the threshold value. The control device 61 stops tilting of the fork 26 when the amount of angular deviation between the fork 26 and the pallet becomes less than the threshold value. By performing the process of step S25, it can be said that the control device 61 includes an auxiliary unit for performing auxiliary control and a tilt auxiliary unit for performing tilt auxiliary control.

In step S31, the control device 61 performs tilt prohibition control for prohibiting tilt assist control. That is, during the tilt operation, it is prohibited to assist the control device 61 so as to reduce the deviation of the inclination between the fork 26 and the pallet. In the tilt assist control, when the amount of angular deviation between the fork 26 and the pallet becomes less than the threshold value, the tilt of the fork 26 is stopped. By prohibiting tilt assist control, it is suppressed that the fork 26 is automatically stopped during the tilt operation. By performing the process of step S31, it can be said that the control device 61 includes a prohibition unit for performing prohibition control and a tilt prohibition unit for performing tilt prohibition control.

As described above, the control device 61 prohibits the lift assist control when the lift operation unit 35 is performing the lift operation, and prohibits the tilt assist control when the tilt operation unit 36 is performing the tilt operation. is doing. When the operation unit 34 is operated, it can be said that the control device 61 prohibits assistance for the same cargo handling operation as the cargo handling operation performed by the cargo handling device 21 by the operation of the operation unit 34.

The operation of the first embodiment will be described.
As shown in FIG. 6, a case where the pallet P placed on the shelf R is picked up will be described as an example. The shelf R includes a plurality of shelf boards B. The shelf boards B are provided so as to be separated from each other in the vertical direction. A pallet P is arranged on the shelf board B. Three of the plurality of pallets P are arranged vertically apart from each other. The pallet P includes an insertion hole H. A load W is loaded on the pallet P.

When vertically aligning the pallet P located at the uppermost position of the three pallets P with the fork 26, the operator raises the fork 26 by operating the lift operation unit 35. During the lift operation, assistance for the lift operation by the control device 61 is prohibited. Therefore, the position of the fork 26 in the vertical direction is determined by the operation of the lift operation unit 35 by the operator. In the state shown in FIG. 6, in the operation of the operator, a positional shift in the vertical direction occurs between the fork 26 and the pallet P. The operator starts the reach-out operation by operating the reach operation unit 37 in this state.

As shown in FIG. 7, when the reach-out operation is started, the control device 61 performs lift assist control to assist the lift operation. In the example shown in FIG. 7, the fork 26 is raised by a predetermined amount A1 from the state shown in FIG. As a result, the vertical positional deviation between the fork 26 and the pallet P is reduced. Even if the position shift between the fork 26 and the pallet P in the vertical direction occurs when the operator finishes the operation of the lift operation unit 35, the position shift is eliminated during the reach-out operation.

When adjusting the inclination of the pallet P located at the uppermost position of the three pallets P and the fork 26, the operator tilts the fork 26 by operating the tilt operation unit 36. In the state shown in FIG. 8, a deviation in inclination occurs between the fork 26 and the pallet P in the operation by the operator. The operator starts the reach-out operation by operating the reach operation unit 37 in this state.

As shown in FIG. 9, when the reach-out operation is started, the control device 61 performs tilt assist control to assist the tilt operation. In the example shown in FIG. 9, the fork 26 is tilted backward by a predetermined angle θ1 from the state shown in FIG. As a result, the deviation of the inclination between the fork 26 and the pallet P becomes small. Even if the tilt of the fork 26 and the pallet P is misaligned when the operator finishes the operation of the tilt operation unit 36, the misalignment of the fork 26 and the pallet P is eliminated during the reach-out operation.

The effect of the first embodiment will be described.
(1-1) When a cargo handling operation is performed by the operation of the operation unit 34, assistance for the same cargo handling operation as the cargo handling operation is prohibited. When the operator is operating the operation unit 34, it is suppressed that the cargo handling operation by the operation unit 34 is restricted by the control device 61. For example, the lift operation is automatically stopped even though the operator is operating the lift operation unit 35, or the tilt operation is automatically stopped even though the operator is operating the tilt operation unit 36. Is suppressed. Since the operation of the operator is not restricted by the control device 61, the discomfort of the operator can be reduced and the deterioration of the operability of the forklift 10 can be suppressed.

(1-2) When the control device 61 is performing the lift operation by operating the lift operation unit 35, the control device 61 does not perform the lift assist control. It is suppressed that the lift operation by the operation of the lift operation unit 35 is restricted by the assistance of the control device 61.

(1-3) When the tilt operation is performed by the operation of the tilt operation unit 36, the control device 61 does not perform the tilt assist control. It is suppressed that the tilt operation by the operation of the tilt operation unit 36 is restricted by the assistance of the control device 61.

(1-4) The control device 61 controls the hydraulic mechanism 45 so that the misalignment between the fork 26 and the cargo handling target becomes small in the process of the fork 26 approaching the cargo handling target. At the stage of bringing the fork 26 closer to the cargo handling target, it is assumed that the operator has completed the alignment between the fork 26 and the cargo handling target. After the operator finishes the alignment between the fork 26 and the cargo handling target, by reducing the deviation caused by this alignment, the control device 61 assists even though the alignment has not been completed. Can be suppressed.

(Second Embodiment)
A second embodiment of the forklift will be described. In the following description, the description of the same parts as those of the first embodiment will be omitted, and the differences from the first embodiment will be described.

As shown in FIG. 10, the cargo handling device 21 includes a side shift device 80. The side shift device 80 moves the fork 26 in the left-right direction. The side shift device 80 of the present embodiment moves both of the two forks 26 in the left-right direction while maintaining the distance between the two forks 26.

The side shift device 80 is attached to the lift bracket 25. The lift bracket 25 includes two

finger bars

71 and 72. The two

finger bars

71 and 72 are provided at intervals in the vertical direction.

The side shift device 80 includes a shifter 81 and a shift cylinder 86.
The shifter 81 is provided so as to be movable to the left and right with respect to the two

finger bars

71 and 72. The shifter 81 includes two

shifter bars

82, 83 and two connecting

members

84, 85 that connect the two

shifter bars

82, 83. The two

shifter bars

82 and 83 are provided at intervals in the vertical direction. The two connecting

members

84 and 85 are provided at intervals in the left-right direction. The connecting

members

84 and 85 connect the ends of the shifter bars 82 and 83 to each other. A fork 26 is connected to the shifter bars 82 and 83.

The shift cylinder 86 is a hydraulic cylinder. The shifter 81 moves in the left-right direction by supplying and discharging the hydraulic oil to the shift cylinder 86. The fork 26 also moves in the left-right direction together with the shifter 81.

As shown in FIG. 11, the operation unit 34 includes a side shift operation unit 38. The forklift 10 includes a side shift sensor 90. The detection unit 46 includes a shift amount sensor 91.
The side shift operation unit 38 is operated by an operator. The side shift operation unit 38 of this embodiment is a lever. The side shift operation unit 38 tilts forward or backward from the neutral position. The side shift operation unit 38 is operated when the fork 26 is moved in the left-right direction.

The side shift sensor 90 detects the amount of operation of the side shift operation unit 38. The side shift sensor 90 outputs an electric signal according to the amount of operation of the side shift operation unit 38. If the operation amount of the side shift operation unit 38 is detected by the side shift sensor 90, it can be said that the side shift operation unit 38 is being operated. If the operation amount of the side shift operation unit 38 is not detected by the side shift sensor 90, it can be said that the side shift operation unit 38 is not operated. The detection result of the side shift sensor 90 can be said to be information indicating whether or not the side shift operation unit 38 is operated.

The shift amount sensor 91 detects the shift amount. The shift amount is an amount in which the fork 26 is moved in the left-right direction by the side shift device 80. The shift amount is, for example, the amount of movement from the reference when the center position of the two forks 26 and the center position of the lift bracket 25 in the left-right direction coincide with each other.

The control device 61 causes the cargo handling device 21 to perform a side shift operation according to the detection result of the side shift sensor 90. The cargo handling operation of the second embodiment includes a side shift operation of moving the fork 26 in the left-right direction. The side shift operation unit 38 corresponds to the side shift operation.

The control device 61 performs side shift auxiliary control as an auxiliary control to assist the side shift operation. Hereinafter, the side shift auxiliary control will be described. Similar to the first embodiment, as an example, a side shift auxiliary control when performing a loading operation for loading a pallet on a fork 26 will be described.

The side shift auxiliary control is started, for example, on condition that the side shift operation is started. The control device 61 starts the side shift operation if the operation amount of the side shift operation unit 38 is detected by the side shift sensor 90. The control device 61 starts side shift auxiliary control accordingly. The side shift auxiliary control is repeatedly performed in a predetermined control cycle.

As shown in FIG. 12, in step S41, the control device 61 acquires the world coordinates of the pallet. The world coordinates of the palette can be obtained from the image processing device 52.

Next, in step S42, the control device 61 determines whether or not the position of the fork 26 and the pallet is displaced. In the side shift auxiliary control, the positional deviation between the fork 26 and the pallet is a relative positional deviation between the fork 26 and the pallet in the left-right direction. More specifically, the deviation between the center position of the two forks 26 and the center position in the left-right direction of the pallet in the left-right direction is the relative positional deviation between the fork 26 and the pallet in the left-right direction.

Whether or not the position of the fork 26 and the pallet is misaligned can be determined based on the X coordinate indicating the center position of the two forks 26 and the X coordinate of the pallet. The X coordinate indicating the center position of the two forks 26 coincides with the origin of the world coordinate system. From the X coordinate of the palette, the X coordinate indicating the center position in the left-right direction of the palette can be derived. The control device 61 regards the difference between the X coordinate indicating the center position of the two forks 26 and the X coordinate indicating the center position in the left-right direction of the pallet as the amount of misalignment between the fork 26 and the pallet. If the amount of misalignment between the fork 26 and the pallet is less than the threshold value, the control device 61 determines that no misalignment has occurred. If the amount of misalignment between the fork 26 and the pallet is equal to or greater than the threshold value, the control device 61 determines that the misalignment has occurred. If the determination result in step S42 is negative, the control device 61 ends the side shift auxiliary control. If the determination result in step S42 is affirmative, the control device 61 performs the process of step S43.

In step S43, the control device 61 determines whether or not the side shift operation is in progress. In other words, the control device 61 determines whether or not the side shift operation has been stopped. If the operation amount of the side shift operation unit 38 is detected by the side shift sensor 90, the control device 61 determines that the side shift operation is in progress. The control device 61 determines that the side shift operation is not in progress unless the operation amount of the side shift operation unit 38 is detected by the side shift sensor 90. If the determination result in step S43 is affirmative, the control device 61 performs the process of step S51. If the determination result in step S43 is negative, the control device 61 performs the process of step S44.

Step S44 is the same process as step S4. If the determination result in step S44 is negative, the control device 61 ends the side shift auxiliary control. If the determination result in step S44 is affirmative, the control device 61 performs the process of step S45.

In step S45, the control device 61 performs side shift assist control to assist the side shift operation. The side shift auxiliary control is to control the cargo handling device 21 so that the control device 61 reduces the positional deviation between the fork 26 and the pallet in the left-right direction. The control device 61 controls so as to reduce the misalignment during the reach-out operation. The control device 61 moves the fork 26 in the left-right direction by controlling the hydraulic mechanism 45. For example, the control device 61 moves the fork 26 in the left-right direction so that the amount of misalignment between the fork 26 and the pallet is less than the threshold value. When the amount of misalignment between the fork 26 and the pallet becomes less than the threshold value, the control device 61 stops the fork 26 from moving in the left-right direction. By performing the process of step S45, it can be said that the control device 61 includes an auxiliary unit for performing auxiliary control and a side shift auxiliary unit for performing side shift auxiliary control.

In step S51, the control device 61 performs side shift prohibition control that prohibits side shift auxiliary control. That is, during the side shift operation, it is prohibited to assist the control device 61 so as to reduce the positional deviation between the fork 26 and the pallet. In the side shift auxiliary control, when the amount of misalignment between the fork 26 and the pallet becomes less than the threshold value, the fork 26 stops moving in the left-right direction. By prohibiting the side shift auxiliary control, it is suppressed that the fork 26 is automatically stopped during the side shift operation. By performing the process of step S51, it can be said that the control device 61 includes a prohibition unit for performing prohibition control and a side shift prohibition unit for performing side shift prohibition control.

The operation of the second embodiment will be described.
As shown in FIG. 13, when loading the pallet P, the forklift 10 is moved so that the fork 26 and the pallet P face each other. When the position shift relative to the left-right direction occurs between the fork 26 and the pallet P, the operator operates the side shift operation unit 38 to move the fork 26 in the left-right direction. During the side shift operation, the side shift auxiliary control by the control device 61 is prohibited. Therefore, the position of the fork 26 in the left-right direction is determined by the operation of the side shift operation unit 38 by the operator. In the state shown in FIG. 13, in the operation of the operator, a positional shift in the left-right direction occurs between the fork 26 and the pallet P. The operator starts the reach-out operation by operating the reach operation unit 37 in this state.

As shown in FIG. 14, the control device 61 performs side shift auxiliary control when the reach-out operation is started. In the example shown in FIG. 14, the fork 26 is moved to the right of A2 by a predetermined amount from the state shown in FIG. As a result, the positional deviation between the fork 26 and the pallet P in the left-right direction is reduced. Even if the position shift between the fork 26 and the pallet P in the left-right direction occurs when the operator finishes the operation of the side shift operation unit 38, the position shift is eliminated during the reach-out operation.

The effect of the second embodiment will be described. In the second embodiment, the following effects can be obtained in addition to the effects of the first embodiment.
(2-1) When the side shift operation is performed by the operation of the side shift operation unit 38, the control device 61 does not perform the side shift auxiliary control. It is suppressed that the side shift operation by the operation of the side shift operation unit 38 is restricted by the assistance of the control device 61.

Each embodiment can be modified and implemented as follows. The embodiments and the following modifications can be implemented in combination with each other within a technically consistent range.
○ In each embodiment, the lift assist control by the control device 61 may be prohibited during the lift operation, and may be performed at a timing different from that during the reach-out operation. For example, the lift assist control by the control device 61 may be performed at the timing when the determination in step S4 is omitted and the determination in step S3 is negative. The lift assist control by the control device 61 may be performed during the tilt operation or the side shift operation.

○ In each embodiment, the tilt assist control by the control device 61 may be prohibited during the tilt operation, and may be performed at a timing different from that during the reach-out operation. For example, the determination in step S24 may be omitted, and the tilt operation may be assisted by the control device 61 at the timing when the determination in step S23 becomes negative. The tilt assist control by the control device 61 may be performed during the lift operation or the side shift operation.

○ In the second embodiment, the side shift auxiliary control by the control device 61 may be prohibited during the side shift operation, and may be performed at a timing different from that during the reach out operation. For example, the determination in step S44 may be omitted, and the side shift auxiliary control may be performed by the control device 61 at the timing when the determination in step S43 is negative. The side shift auxiliary control by the control device 61 may be performed during the lift operation or the tilt operation.

○ In the first embodiment, the control device 61 may perform either tilt assist control or lift assist control as auxiliary control. In the second embodiment, the control device 61 may perform only the side shift auxiliary control as the auxiliary control. That is, the control device 61 may perform at least one of tilt assist control, lift assist control, and side shift assist control.

○ In each embodiment, the cargo handling target may be a loading place. Even if the cargo handling target is a cargo handling area, the deviation between the fork 26 and the cargo handling object can be derived from the world coordinates and inclination of the cargo handling area. Therefore, the control device 61 can assist the cargo handling operation as in the case where the cargo handling target is the pallet.

○ In each embodiment, the forklift 10 may be remotely controlled. In this case, the operator operates the forklift 10 at a remote location away from the forklift 10. The operator operates an operation terminal provided at a remote location. As the operation terminal, a dedicated device can be used, or a mobile communication terminal such as a tablet terminal can be used. The operation terminal includes an operation unit for operating the forklift 10, an operation amount detection unit for detecting the operation amount of the operation unit, and a communication device. The operation unit may be a physical member such as a lever, or may be a touch panel displaying a symbol functioning as the operation unit. When the operation terminal displays a symbol functioning as an operation unit on the touch panel, the cargo handling operation of the forklift 10 is performed by operating the touch panel. For example, the cargo handling operation of the forklift 10 is performed by the operator's tap operation or slide operation on the touch panel. In this case, the operation amount is the number of taps and the slide amount, and the touch panel functions as the operation amount detection unit. The communication device generates data in a predetermined format and transmits this data to the forklift 10. The communication device transmits information such as the amount of operation of the operation unit so that the control device 61 can determine whether or not the operation unit is being operated.

The forklift 10 includes an in-vehicle communication device. The in-vehicle communication device receives the data transmitted from the communication device and outputs the data to the control device 61. The control device 61 operates the forklift 10 according to the data transmitted from the communication device. The control device 61 controls the cargo handling device 21 according to the operation of the operation unit. The control device 61 determines whether or not the operation unit is operated from the data transmitted from the communication device. in this case. It can be said that the in-vehicle communication device functions as an acquisition unit. When the operation unit is operated, the control device 61 performs prohibition control for prohibiting auxiliary control for the same cargo handling operation as the cargo handling operation performed by the cargo handling device 21 by the operation of the operation unit.

○ In each embodiment, when the forklift 10 is a counter type, the forklift 10 may be advanced for loading or unloading instead of the reach-out operation. The control device 61 may assist the cargo handling operation while the forklift 10 is advancing. Even in this case, it can be said that the cargo handling operation is assisted in the process of the fork 26 approaching the cargo handling target.

○ In each embodiment, the forklift 10 may include a ToF (Time of Flight) camera, a LIDAR (Laser Imaging Detection and Ringing), a millimeter-wave radar, or a stereo camera instead of the camera 51. ToF cameras, LIDARs, millimeter-wave radars, and stereo cameras are devices that can measure three-dimensional coordinates in the world coordinate system. Even when these devices are used, the world coordinates and inclination of the cargo handling target can be derived. Therefore, the same control as in the embodiment can be performed.

○ In each embodiment, the forklift 10 may include a display unit on which an image being captured by the camera 51 is captured.
○ In the second embodiment, the side shift device 80 may be a device in which the distance between the two forks 26 changes.

○ In each embodiment, the control device 61 may function as the image processing device 52. That is, the control device 61 and the image processing device 52 may be the same device.

P ... Pallet as a cargo handling object 10 ... Forklift 21 ... Cargo handling device 26 ... Fork 34 ... Operation unit 35 ... Lift operation unit 36 ... Tilt operation unit 38 ... Side shift operation unit 61 ... Acquisition unit, auxiliary unit, prohibition unit, lift assistance A control device as a unit, a lift prohibition unit, a tilt assist unit, a tilt prohibition unit, a side shift assist unit, and a side shift prohibition unit.

Claims

A cargo handling device with a fork,
A control device configured to cause the cargo handling device to perform a cargo handling operation including at least one of a tilt operation, a lift operation, and a side shift operation.
It is provided with an operation unit operated when the cargo handling operation is performed by the cargo handling device, and an acquisition unit for acquiring information indicating whether or not the operation unit operated by the operator is operated.
The control device is
Auxiliary control that assists the operator by controlling the cargo handling device so as to reduce the misalignment between the fork and the cargo handling target by the operator.
When the operation unit is operated, the forklift is characterized in that the operation of the operation unit performs a prohibition control for prohibiting the auxiliary control for the same cargo handling operation as the cargo handling operation performed by the cargo handling device.
The cargo handling operation includes the lift operation.
The operation unit includes a lift operation unit corresponding to the lift operation.
The auxiliary control includes a lift auxiliary control configured to assist the operator so that the relative positional deviation between the fork and the cargo handling target in the vertical direction is small.
The forklift according to claim 1, wherein the prohibition control includes a lift prohibition control that prohibits the lift assist control when the lift operation is performed by the operation of the lift operation unit.
The cargo handling operation includes the tilt operation.
The operation unit includes a tilt operation unit corresponding to the tilt operation.
The auxiliary control includes a tilt assist control configured to assist the operator so that the relative tilt deviation between the fork and the cargo handling target in the front-rear direction is small.
The forklift according to claim 1 or 2, wherein the prohibition control includes a tilt prohibition control that prohibits the tilt assist control when the tilt operation is performed by the operation of the tilt operation unit.
The cargo handling operation includes the side shift operation.
The operation unit includes a side shift operation unit corresponding to the side shift operation.
The auxiliary control includes a side shift auxiliary control configured to assist the operator so that the relative positional deviation between the fork and the cargo handling target in the left-right direction is small.
The prohibition control is any one of claims 1 to 3 including a side shift prohibition control that prohibits the side shift auxiliary control when the side shift operation is performed by the operation of the side shift operation unit. The forklift described in the section.
The forklift according to any one of claims 1 to 4, wherein the auxiliary control assists the operator in the process of the fork approaching the cargo handling target.