JP2022029275A - Control device of cargo handling vehicle - Google Patents

Abstract

To provide a control device of a cargo handling vehicle which can improve certainty of a cargo handling operation of the cargo handling vehicle.SOLUTION: A control device 100 of a cargo handling vehicle 1 includes a calculation part 22 for calculating a change rate of an inner pressure to a stroke amount detected by a stroke detection part 31 based on the stroke amount and an inner pressure detected by an inner pressure detection part 32. In a state where a part of a palette 61 is brought into contact with a mounting surface 62, the inner pressure changes relative to the stroke amount, the change rate of the inner pressure to the stroke amount becomes a predetermined value (see region E2 in Fig. 4). For this reason, when a lift cylinder 4 moves a cargo 60 and the palette 61 up and down, a determination part 23 can determine a contact state between the palette 61 and the mounting surface 62 of the palette 61 based on the change rate calculated by the calculation part 22. Thereby, when the palette 61 is brought into contact with the mounting surface 62, the control device 100 can perform predetermined operation support.SELECTED DRAWING: Figure 2

Description

The present invention relates to a control device for a cargo handling vehicle.

As a control device for a cargo handling vehicle, for example, the one described in Patent Document 1 is known. The cargo handling vehicle described in Patent Document 1 includes a lift cylinder that raises and lowers an object by supplying and discharging hydraulic oil, an operation lever for operating the lift cylinder, and a hydraulic pump that supplies and discharges hydraulic oil to the lift cylinder. To prepare for. The cargo handling vehicle inserts the fork into the hole of the pallet and operates the lift cylinder to lift the pallet through the fork. Here, the control device for the cargo handling vehicle described in Patent Document 1 detects the amount of deviation of the current position with respect to the position where the fork can be inserted into the hole of the pallet by image recognition. As a result, the insertion position of the fork that can safely perform cargo handling action is detected.

Japanese Unexamined Patent Publication No. 2020-7059

Here, in the conventional control device for cargo handling vehicles as described above, the following problems exist. That is, during cargo handling work, when a cargo handling vehicle takes out an object (cargo placed on a pallet) placed in a shelf or the like, the object can be raised to a sufficient height from the mounting surface of the shelf. Sometimes not. For example, when the cargo is heavy, the pallet on which the cargo is placed may be greatly tilted forward due to the subduction of the front wheels of the cargo handling vehicle or the bending of the fork (for example, the state shown in FIG. 3 (b)). .. In such a case, even if the front side of the pallet that can be seen by the driver is separated from the mounting surface, the back side of the pallet that cannot be seen by the driver is in contact with the mounting surface, that is, the ground cannot be completely cut. There is. If the cargo handling vehicle moves forward and backward in this state, the pallet may be damaged or the cargo may fall. Therefore, it is required to improve the certainty of the cargo handling work of the cargo handling vehicle by suppressing the forward / backward movement of the cargo handling vehicle in the state where the object is in contact with the mounting surface.

An object of the present invention is to provide a cargo handling vehicle control device capable of improving the certainty of cargo handling work of a cargo handling vehicle.

The control device for a cargo handling vehicle according to one aspect of the present invention includes a stroke detection unit that detects the stroke amount of a lift cylinder for raising and lowering an object by supplying and discharging hydraulic oil, and an internal pressure detection unit that detects the internal pressure of the lift cylinder. When the lift cylinder moves the object up and down, the unit, the calculation unit that calculates the rate of change of the internal pressure with respect to the stroke amount based on the stroke amount detected by the stroke detection unit and the internal pressure detected by the internal pressure detection unit, and the lift cylinder. A determination unit for determining a contact state between an object and a mounting surface of the object based on the rate of change calculated by the calculation unit is provided.

The control device of the cargo handling vehicle includes a calculation unit that calculates the rate of change of the internal pressure with respect to the stroke amount based on the stroke amount detected by the stroke detection unit and the internal pressure detected by the internal pressure detection unit. When the cargo handling vehicle is moving up and down the object, the internal pressure is constant with respect to the stroke amount and the rate of change of the internal pressure with respect to the stroke amount is zero when the object is completely separated from the mounting surface. .. On the other hand, in a state where a part of the object is in contact with the mounting surface, the internal pressure changes with respect to the stroke amount, and the rate of change of the internal pressure with respect to the stroke amount becomes a predetermined value. Therefore, the determination unit can determine the contact state between the object and the mounting surface of the object based on the rate of change calculated by the calculation unit when the lift cylinder raises and lowers the object. As a result, the control device can provide predetermined driving support when the object is in contact with the mounting surface. From the above, the certainty of the cargo handling work of the cargo handling vehicle can be improved.

Further, when the rate of change calculated by the calculation unit is equal to or higher than a predetermined threshold value, the determination unit may determine that the object is in contact with the mounting surface. As a result, the determination unit can accurately determine the state in which the object is in contact with the mounting surface.

The control device of the cargo handling vehicle further includes a drive control unit that controls the drive unit of the cargo handling vehicle, and when the determination unit determines that the object and the mounting surface are in contact with each other, the drive control unit is the cargo handling vehicle. You may regulate forward and backward movement. In this case, it is possible to prevent the cargo handling vehicle from erroneously moving forward and backward while the object is in contact with the mounting surface.

The control device of the cargo handling vehicle further includes an output unit that outputs information, and when the determination unit determines that the object and the mounting surface are in contact with each other, the output unit may output the caution information. .. In this case, since the driver can notice that the object is in contact with the mounting surface, it is possible to prevent the cargo handling vehicle from moving forward and backward in that state.

According to the present invention, it is possible to provide a control device for a cargo handling vehicle that can improve the certainty of the cargo handling work of the cargo handling vehicle.

It is a side view which shows the cargo handling vehicle provided with the control device which concerns on embodiment of this invention. It is a block diagram which shows the control device of the cargo handling vehicle which concerns on embodiment of this invention. (A) and (b) are schematic views showing how a fork raises and lowers a pallet and a load, and (c) is a schematic view of a lift cylinder. The upper row is a graph showing the relationship between the stroke amount of the lift cylinder and the internal pressure, and the lower row is a graph showing the relationship between the stroke amount of the lift cylinder and the rate of change of the internal pressure. It is a graph which shows the state of comparing the change rate of an internal pressure with a threshold value. It is a flowchart which shows the processing content of the control device of the cargo handling vehicle which concerns on embodiment of this invention.

Hereinafter, preferred embodiments of the control device for the cargo handling vehicle according to the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent elements are designated by the same reference numerals, and duplicate description will be omitted.

FIG. 1 is a side view showing a cargo handling vehicle provided with a control device according to an embodiment of the present invention. In the figure, the cargo handling vehicle 1 according to the present embodiment is a forklift. The cargo handling vehicle 1 includes a vehicle body frame 2 and a mast 3 arranged at the front portion of the vehicle body frame 2. The mast 3 consists of a pair of left and right outer masts 3a that are tiltably supported by the vehicle body frame 2 and an inner mast 3b that is arranged inside these outer masts 3a and can be raised and lowered with respect to the outer mast 3a. There is.

A lift cylinder 4 as an elevating hydraulic cylinder is arranged on the rear side of the mast 3. The tip of the piston rod 4p of the lift cylinder 4 is connected to the upper part of the inner mast 3b.

The lift bracket 5 is supported on the inner mast 3b so as to be able to move up and down. A fork 6 for loading luggage is attached to the lift bracket 5. The fork 6 is configured as an elevating object that is raised and lowered by the lift cylinder 4. A chain wheel 7 is provided on the upper portion of the inner mast 3b, and the chain 8 is mounted on the chain wheel 7. One end of the chain 8 is connected to the lift cylinder 4, and the other end of the chain 8 is connected to the lift bracket 5. When the lift cylinder 4 is expanded and contracted, the fork 6 moves up and down together with the lift bracket 5 via the chain 8.

Tilt cylinders 9 as tilting hydraulic cylinders are supported on both the left and right sides of the vehicle body frame 2. The tip of the piston rod 9p of the tilt cylinder 9 is rotatably connected to the substantially central portion of the outer mast 3a in the height direction. When the tilt cylinder 9 is expanded and contracted, the mast 3 tilts.

A driver's cab 10 is provided on the upper part of the vehicle body frame 2. At the front of the driver's cab 10, a lift operating lever 11 for operating the lift cylinder 4 to raise and lower the fork 6 and a tilt operating lever 12 for operating the tilt cylinder 9 to tilt the mast 3 are provided. Has been done.

Further, a steering wheel 13 for steering is provided in the front portion of the driver's cab 10. The steering 13 is a hydraulic power steering, and it is possible to assist the driver's steering by a PS cylinder as a hydraulic cylinder for power steering (PS).

Further, although not particularly shown, the driver's cab 10 is provided with a direction switch for switching the traveling direction (forward / reverse / neutral) of the cargo handling vehicle 1.

FIG. 2 is a block diagram showing a control device 100 of a cargo handling vehicle 1 according to an embodiment of the present invention. The control device 100 of the present embodiment is a device that controls the cargo handling vehicle 1.

The control device 100 includes a lift operation detection unit 30, a stroke detection unit 31, an internal pressure detection unit 32, a drive unit 33, an output unit 34, and a control unit 20.

The lift operation detection unit 30 detects the operation of the lift operation lever 11 (see FIG. 1). The lift operation detection unit 30 detects that the lift operation lever 11 has been operated, and also detects the operation direction. Therefore, the lift operation detection unit 30 can detect whether an ascending or descending operation has been performed on the lift cylinder 4. The lift operation detection unit 30 may be provided on the lift operation lever 11 or may be provided at a position other than the lift operation lever 11 to detect a signal indicating the operation content. The lift operation detection unit 30 transmits the detection result to the control unit 20.

The stroke detection unit 31 detects the stroke amount of the lift cylinder 4. Here, the stroke amount of the lift cylinder 4 will be described with reference to FIG. 3 (c). As shown in FIG. 3 (c), the piston 4a and the piston rod 4p move up and down by supplying and discharging the hydraulic oil 50 to the internal space between the bottom wall 4b of the lift cylinder 4 and the piston 4a. As a result, the fork 6 (see FIGS. 3 (a) and 3 (b)) moves up and down. Here, the stroke amount of the lift cylinder 4 is defined by the distance between the bottom wall 4b and the piston 4a (dimensions indicated by "S" in the figure). When the hydraulic oil 50 is supplied to the internal space, for example, the piston 4a rises from the position indicated by the virtual line to the position indicated by the solid line, and the stroke amount becomes large. On the other hand, when the hydraulic oil 50 is discharged from the internal space, for example, the piston 4a descends from the position indicated by the solid line to the position indicated by the virtual line, and the stroke amount becomes small. The stroke detection unit 31 may directly detect the stroke amount or may detect a parameter indirectly indicating the stroke amount. For example, the stroke detection unit 31 may directly detect the stroke amount with a sensor provided on the lift cylinder 4, may detect the stroke amount from the movement amount of the chain 8, or the like, or may detect the stroke amount from the lift operation lever 11. The stroke amount may be detected from the operation amount of. The stroke detection unit 31 transmits the detection result to the control unit 20.

Returning to FIG. 2, the internal pressure detection unit 32 detects the internal pressure of the lift cylinder 4. The internal pressure of the lift cylinder 4 is the magnitude of the pressure generated in the internal space of the lift cylinder 4. The internal pressure of the lift cylinder 4 increases as the load acting on the fork 6 increases, and decreases as the load acting on the fork 6 decreases. The internal pressure detection unit 32 may directly detect the internal pressure or may detect a parameter indirectly indicating the internal pressure. The internal pressure detection unit 32 may be configured by, for example, a pressure sensor that detects the hydraulic pressure acting on the lift cylinder 4, or may be configured by a strain cage or a pressure sensor that detects the load acting on the fork 6. The internal pressure detection unit 32 transmits the detection result to the control unit 20.

The drive unit 33 applies a driving force for the cargo handling vehicle 1 to travel. The drive unit 33 is composed of a drive source such as a motor or an engine, a transmission mechanism for transmitting the driving force of the drive source to the wheels, and the like.

The output unit 34 is a unit that outputs various information. The output unit 34 may output information for driving support. The output unit 34 may be configured by a monitor, a speaker, a warning light, or the like.

The control unit 20 is composed of a CPU, RAM, ROM, and the like. The control unit 20 includes an information acquisition unit 21 (stroke detection unit, internal pressure detection unit), a calculation unit 22, a determination unit 23, a drive control unit 24, and a driving support unit 25. The control unit 20 may be configured as one or more processors that operate according to a program, one or more dedicated hardware circuits such as an ASIC, or a circuit including a combination thereof. The processor has a CPU and a memory such as RAM and ROM. Various programs for processing information are stored in the memory, and the CPU reads various programs to perform operations.

The information acquisition unit 21 acquires various information necessary for controlling the cargo handling vehicle 1. The information acquisition unit 21 acquires the detection results from the lift operation detection unit 30, the stroke detection unit 31, and the internal pressure detection unit 32.

The calculation unit 22 calculates the rate of change of the internal pressure with respect to the stroke amount based on the stroke amount detected by the stroke detection unit 31 and the internal pressure detected by the internal pressure detection unit 32. Here, the relationship between the stroke amount and the internal pressure will be described with reference to FIGS. 3 (a) and 3 (b) and FIG. FIG. 3A shows a state in which the pallet 61 (object) on which the luggage 60 (object) is placed is in complete contact with the mounting surface 62. FIG. 3B shows a state in which the pallet 61 is completely separated from the mounting surface 62. As shown in FIG. 3B, due to the influence of the weight of the luggage 60, the front wheel sinks and the fork 6 bends, so that the fork 6 is at a position lower on the tip side than on the base end side. Tilt to be placed in. Therefore, the lower end 61b on the inner side of the pallet 61 is arranged at a position lower than the lower end 61a on the front side of the pallet 61. Therefore, in the state on the way from FIG. 3A to FIG. 3B, the lower end 61a on the front side of the pallet 61 floats from the mounting surface 62, while the lower end 61b on the back side contacts the mounting surface 62. (See the pallet 61 shown by the virtual line in FIG. 3A). In the following description, the state shown in FIG. 3B is referred to as "ground cutting state", and the state in which the lower end 61a floats and the lower end 61b is in contact with the mounting surface 62 is "the state before ground cutting". May be called.

The upper graph of FIG. 4 is a graph showing the relationship between the stroke amount of the lift cylinder 4 and the internal pressure, the horizontal axis shows the stroke amount, and the vertical axis shows the internal pressure. When the pallet 61 as shown in FIG. 3A is in complete contact with the mounting surface 62, the fork 6 is not in contact with the pallet 61. Therefore, the internal pressure becomes constant at the reference value with respect to the increase in the stroke amount (region E1 in the “stroke amount <S1”). When the stroke amount becomes S1, the fork 6 comes into contact with the pallet 61, so that the lower end 61b on the back side of the pallet 61 comes into contact with the mounting surface 62, while the lower end 61a on the front side separates from the mounting surface 62. At this time, as the fork 6 rises, the load of the pallet 61 and the luggage 60 acts on the fork 6 more, so that the internal pressure rises (region E2 of “S1 ≦ stroke amount <S2”). When the stroke amount becomes S2, the pallet 61 is ground-cut, and as shown in FIG. 3B, the entire pallet 61 is separated from the mounting surface 62. In this state, since the fork 6 maintains a state in which all the loads of the pallet 61 and the load 60 are supported, the internal pressure becomes constant at the value of P1 with respect to the increase in the stroke amount (“S2 ≦ stroke amount”). Area E3).

The calculation unit 22 calculates the rate of change of the internal pressure with respect to the stroke amount based on the relationship between the stroke amount and the internal pressure as shown in the upper part of FIG. The calculation result is shown in the lower graph of FIG. The horizontal axis of this graph shows the stroke amount, and the vertical axis shows the rate of change of the internal pressure. As shown in the graph, in the regions E1 and E3, the internal pressure is constant, so the rate of change is zero. On the other hand, in the region E2, the internal pressure increases as the stroke amount increases. Therefore, the rate of change in the internal pressure is constant at the value of P'2 with respect to the stroke amount.

A similar graph as shown in FIG. 4 is drawn when the fork 6 is raised and when the fork 6 is lowered. That is, when the fork 6 is raised, the internal pressure and the rate of change shown in the graph of FIG. 4 change in the direction in which the stroke amount increases, but when the fork 6 is lowered, the internal pressure shown in the graph of FIG. 4 changes. And the rate of change changes in the direction in which the stroke amount becomes smaller.

The determination unit 23 determines the contact state between the pallet 61 and the mounting surface 62 based on the rate of change calculated by the calculation unit 22 when the lift cylinder 4 raises and lowers the pallet 61 and the load 60. When the rate of change calculated by the calculation unit 22 is equal to or higher than a predetermined threshold value, the determination unit 23 determines that the pallet 61 is in contact with the mounting surface 62. Specifically, as shown in FIG. 5, the threshold TV is set with respect to the rate of change in the internal pressure. Further, a region where the rate of change of the internal pressure is equal to or higher than the threshold value TV is set as the defect determination region JE. The determination unit 23 determines that a defect occurs when the cargo handling vehicle 1 moves forward and backward when the rate of change in the internal pressure exists in the defect determination region JE. The defect is that the cargo handling vehicle 1 moves forward and backward with the pallet 61 in contact with the mounting surface 62 in the state before the ground cutting. As shown in FIG. 5, since the rate of change in the region E2 is P'2 equal to or higher than the threshold value TV, the determination unit 23 determines that the region E2 is in a state where the pallet 61 and the mounting surface 62 are in contact with each other. Judge that there is.

The drive control unit 24 controls the drive unit 33 of the cargo handling vehicle 1. When the cargo handling vehicle 1 moves forward, the drive control unit 24 transmits a signal to the drive unit 33 to move forward, and when the cargo handling vehicle 1 moves backward, the drive control unit 24 transmits a signal to the drive unit 33 to move backward. When the determination unit 23 determines that the pallet 61 and the mounting surface 62 are in contact with each other, the drive control unit 24 regulates the forward / backward movement of the cargo handling vehicle 1. When the drive control unit 24 is set to the forward / backward regulation mode, the drive control unit 24 does not transmit a signal to the drive unit 33 even if the driver inputs an operation to move forward or backward.

The driving support unit 25 supports the driver in driving the cargo handling vehicle 1. When the determination unit 23 determines that the pallet 61 and the mounting surface 62 are in contact with each other, the driving support unit 25 provides driving support so that the forward / backward movement of the cargo handling vehicle 1 in that state is suppressed. For example, when the determination unit 23 determines that the pallet 61 and the mounting surface 62 are in contact with each other, the driving support unit 25 sets the forward / backward restriction mode as described above. Further, when the determination unit 23 determines that the pallet 61 and the mounting surface 62 are in contact with each other, the operation support unit 25 outputs the caution information by the output unit 34. The alert information is, for example, a warning that the pallet 61 is still in contact with the mounting surface 62. For example, when the output unit 34 is composed of a warning lamp or the like, the driving support unit 25 may make the warning lamp emit light.

Next, with reference to FIG. 6, the content of the control process of the control device 100 of the cargo handling vehicle 1 according to the present embodiment will be described. The process of FIG. 6 is repeatedly executed by the control unit 20 at a predetermined timing. As shown in FIG. 6, the information acquisition unit 21 of the control unit 20 detects the lift operation based on the detection result of the lift operation detection unit 30 (step S10). The information acquisition unit 21 can detect whether the fork 6 is an operation for raising or lowering the luggage 60 and the pallet 61. Next, the information acquisition unit 21 of the control unit 20 detects the stroke amount and the internal pressure of the lift cylinder 4 (step S20). The information acquisition unit 21 acquires the stroke amount of the lift cylinder 4 based on the detection result of the stroke detection unit 31. The information acquisition unit 21 acquires the internal pressure of the lift cylinder 4 based on the detection result of the internal pressure detection unit 32. As a result, the calculation unit 22 can draw a graph as shown in the upper part of FIG.

Next, the calculation unit 22 of the control unit 20 calculates the rate of change of the internal pressure based on the stroke amount and the internal pressure of the lift cylinder 4 acquired in step S20 (step S30). As a result, the calculation unit 22 can draw a graph as shown in the lower part of FIG. Next, the determination unit 23 of the control unit 20 determines whether or not the rate of change calculated in step S30 is smaller than a predetermined threshold value (step S40).

When the determination unit 23 determines in step S40 that the rate of change is equal to or greater than the threshold value, it can be determined that the pallet 61 is in the state before ground cutting. For example, as shown in FIG. 5, when the stroke amount is in the range of the region E2, the rate of change in the internal pressure is P'2, which is larger than the threshold TV, so that it is determined to be in the state before ground cutting. Therefore, the driving support unit 25 of the control unit 20 provides driving support so that the cargo handling vehicle 1 can be prevented from moving forward and backward in the state before the ground cutting (step S60). Specifically, the driving support unit 25 outputs the attention alert information from the output unit 34. Alternatively or additionally, the driving support unit 25 sets a forward / backward regulation mode that regulates the forward / backward movement of the cargo handling vehicle 1. As a result, the drive control unit 24 regulates the transmission of the forward signal and the reverse signal to the drive unit 33.

On the other hand, when the determination unit 23 determines in step S40 that the rate of change is smaller than the threshold value, the pallet 61 is completely in contact with the mounting surface 62 (see FIG. 3A), or the pallet 61 is completely in contact with the mounting surface 62. Since it is separated from the mounting surface 62 (see FIG. 3B), it can be determined that no problem occurs even if the cargo handling vehicle 1 moves forward and backward. For example, as shown in FIG. 5, when the stroke amount is in the range of the region E1 or the region E3, the rate of change of the internal pressure is 0, which is smaller than the threshold TV, so that it can be determined that no problem occurs. Therefore, the driving support unit 25 of the control unit 20 releases the driving support set in step S60 (step S50). That is, the driving support unit 25 stops the output when the output unit 34 outputs the warning information, and cancels the mode when the forward / backward regulation mode is set. If the driving support has not been provided, the driving support unit 25 does not perform any special processing in step S50. When step S50 is completed, the process is repeated from step S10.

The process shown in FIG. 6 may be constantly executed while the cargo handling vehicle 1 is in operation, or the process shown in FIG. 6 may be started at the timing when the lift operation lever 11 is operated. At this time, when the operation of the lift operation lever 11 is stopped, the control unit 20 may stop the process of FIG. At this time, when the operation of the lift operation lever 11 is restarted, the process may be restarted from the previous stop point.

Next, the operation / effect of the control device 100 of the cargo handling vehicle 1 according to the present embodiment will be described.

First, as a comparative example, a control device that does not determine the ground cutting of the pallet 61 based on the rate of change of the internal pressure will be described. During cargo handling work, when the cargo handling vehicle 1 takes out the luggage 60 placed in the shelf or the like, the luggage 60 and the pallet 61 may not be raised to a sufficient height from the mounting surface 62 of the shelf (). For example, because it interferes with the upper shelf). When the luggage 60 is heavy, the pallet 61 on which the luggage 60 is placed may be greatly tilted forward due to the subduction of the front wheels of the cargo handling vehicle 1 or the deflection of the fork 6 (for example, as shown in FIG. 3B). State). In such a case, even if the front side of the pallet 61 visible to the driver is separated from the mounting surface 62, the back side of the pallet invisible to the driver is in contact with the mounting surface, that is, completely cut off. Sometimes not. If the cargo handling vehicle 1 moves forward and backward in this state, the pallet 61 may be damaged or the luggage 60 may fall.

On the other hand, the control device 100 of the cargo handling vehicle 1 according to the present embodiment determines the rate of change of the internal pressure with respect to the stroke amount based on the stroke amount detected by the stroke detection unit 31 and the internal pressure detected by the internal pressure detection unit 32. A calculation unit 22 for calculation is provided. When the cargo handling vehicle 1 is moving the luggage 60 and the pallet 61 up and down, the pallet 61 is completely in contact with the mounting surface 62 and is separated from the mounting surface 62 with respect to the stroke amount. The internal pressure becomes constant, and the rate of change of the internal pressure with respect to the stroke amount becomes zero (see regions E1 and E3 in FIG. 4). On the other hand, when a part of the pallet 61 is in contact with the mounting surface 62, the internal pressure changes with respect to the stroke amount, and the rate of change of the internal pressure with respect to the stroke amount becomes a predetermined value (region E2 in FIG. 4). reference). Therefore, the determination unit 23 is in contact with the pallet 61 and the mounting surface 62 of the pallet 61 based on the rate of change calculated by the calculation unit 22 when the lift cylinder 4 raises and lowers the load 60 and the pallet 61. Can be determined. As a result, the control device 100 can provide predetermined driving support when the pallet 61 is in contact with the mounting surface 62. From the above, the certainty of the cargo handling work of the cargo handling vehicle 1 can be improved.

Further, the determination unit 23 may determine that the pallet 61 is in contact with the mounting surface 62 when the rate of change calculated by the calculation unit 22 is equal to or greater than a predetermined threshold value. As a result, the determination unit 23 can accurately determine the state in which the pallet 61 is in contact with the mounting surface 62. For example, even if the rate of change in the internal pressure of the lift cylinder 4 rises temporarily for operational reasons, the determination unit 23 does not determine that a problem occurs unless the rate of change reaches the threshold value VT. .. In this way, it is possible to prevent the determination unit 23 from erroneously determining that a problem occurs.

When the control device 100 of the cargo handling vehicle 1 further includes a drive control unit 24 for controlling the drive unit 33 of the cargo handling vehicle 1 and the determination unit 23 determines that the pallet 61 and the mounting surface 62 are in contact with each other. The drive control unit 24 regulates the forward / backward movement of the cargo handling vehicle 1. In this case, it is possible to prevent the cargo handling vehicle 1 from erroneously moving forward and backward while the pallet 61 is in contact with the mounting surface 62.

The control device 100 of the cargo handling vehicle 1 further includes an output unit 34 that outputs information, and when the determination unit 23 determines that the pallet 61 and the mounting surface 62 are in contact with each other, the output unit 34 calls attention. Output information. In this case, since the driver can notice that the pallet 61 is in contact with the mounting surface 62, the cargo handling vehicle 1 can be prevented from moving forward and backward in that state.

Although some suitable embodiments of the cargo handling vehicle control device according to the present invention have been described above, the present invention is not limited to the above embodiments.

Further, the graphs shown in FIGS. 4 and 5 are merely examples, and are appropriately changed according to the structure of the cargo handling vehicle and the type and weight of the object to be handled. For example, when loading and unloading a load lighter than the load handled in FIG. 4, the internal pressure in the region E3 of the lift cylinder is smaller than P1, and the stroke amount of the ground cutting is also smaller than S2.

1 ... Cargo handling vehicle, 4 ... Lift cylinder, 31 ... Stroke detection unit, 32 ... Internal pressure detection unit, 21 ... Information acquisition unit (stroke detection unit, internal pressure detection unit), 22 ... Calculation unit, 23 ... Judgment unit, 24 ... Drive Control unit, 34 ... Output unit, 100 ... Control device.

Claims (4)

A stroke detection unit that detects the stroke amount of the lift cylinder for raising and lowering the object by supplying and discharging hydraulic oil, and
An internal pressure detection unit that detects the internal pressure of the lift cylinder, and
A calculation unit that calculates the rate of change of the internal pressure with respect to the stroke amount based on the stroke amount detected by the stroke detection unit and the internal pressure detected by the internal pressure detection unit.
A determination unit that determines the contact state between the object and the mounting surface of the object based on the rate of change calculated by the calculation unit when the lift cylinder raises and lowers the object. A control device for cargo handling vehicles. The first aspect of the present invention, wherein the determination unit determines that the object is in contact with the above-mentioned mounting surface when the rate of change calculated by the calculation unit is equal to or higher than a predetermined threshold value. Control device for cargo handling vehicles. A drive control unit that controls the drive unit of the cargo handling vehicle is further provided.
The cargo handling vehicle according to claim 1 or 2, wherein when the determination unit determines that the object is in contact with the above-mentioned mounting surface, the drive control unit regulates the forward / backward movement of the cargo handling vehicle. Control device. It also has an output section that outputs information.
The cargo handling according to any one of claims 1 to 3, wherein when the determination unit determines that the object is in contact with the above-mentioned placing surface, the output unit outputs attention-calling information. Vehicle control device.

Images