JPH04317999A - Lifting position correction device for unmanned industrial vehicle - Google Patents

Abstract

PURPOSE:To shorten the time for loading works. CONSTITUTION:The amount of wear on a driving wheel 6 is sensed on the basis of the number of pulses emitted by a rotary encoder 7 for running. The lift. position of a fork 16 is determined on the basis of the obtained wear amount, the number of pulses emitted by another rotary encoder 17 for the lift, and the lift position which was set previously.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lifting height position correction device for an unmanned industrial vehicle such as a forklift.

0002

[Prior Art] Conventionally, the forks of commonly used unmanned industrial vehicles, such as unmanned forklifts, accurately capture loads placed in the work area, so they can extremely accurately reach the lifting height position corresponding to the pallet at the loading area. need to rise. Therefore, during work, it is necessary to constantly monitor the lift height position of the fork using a lift height position detector, and if an error occurs, necessary corrections must be made sequentially.

[0003] The biggest cause of this error is tire wear. The applicant previously proposed a correction means for correcting errors caused by this wear (Japanese Patent Application Laid-Open No. 2-38300).
. This correction means sets the floor surface at a reference position, returns the fork once to the floor surface, detects the reference position, and uses the detection signal to reset the lift height position detector. Then, the lift height position detector detects the lift height position of the fork at each time based on this reference position (floor surface), and compares this value with the reference value to detect the lift height position of the fork from the floor surface. The actual lifting height position is determined. Therefore, even if the tires wear out and the vehicle height decreases, it is possible to always detect the actual lift height position.

0004

[Problems to be Solved by the Invention] However, in the above-mentioned unmanned forklift, each time the tires wear out, the fork must be returned to the floor to reset the lifting height position detector. There was a problem in that the amount of time it took to enter and exit the warehouse was increased by the amount of time it took to reset.

The present invention has been made to solve the above-mentioned problems, and its object is to provide a lifting height position correction device for an unmanned industrial vehicle that can shorten the time required for cargo handling operations.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a lifting amount detection means for detecting the lifting amount of an attachment in an unmanned vehicle, and a lifting amount detection means for detecting the lifting amount of the attachment based on a detection signal of the lifting amount detection means. Lift height position calculation means for calculating the high position, rotation amount detection means for detecting the amount of rotation of the tire, and travel judgment means for detecting the indicating means for indicating a predetermined reference distance and determining whether the reference distance has been traveled. and a wear amount calculation means for calculating the amount of wear of the tire based on the rotation amount detection means and the running judgment means, and a lift height calculated by the lift height position calculation means based on the calculation result of the wear amount calculation means. The gist of the present invention is a lifting height position correction device for an unmanned industrial vehicle, which comprises a correction means for correcting the position.

[0007]

[Operation] When the lifting amount of the attachment is detected by the lifting amount detecting means, the lifting height position calculating means calculates the lifting height position of the attachment based on the detection signal of the lifting amount detecting means. The rotation amount of the tire is detected by the rotation amount detection means, the indication means indicating a predetermined reference distance is detected by the travel determination means, and the wear amount calculation means determines that the rotation amount is detected. The amount of tire wear is calculated based on the means and the driving determination means. Subsequently, the lift height position of the attachment is corrected by the correction means to the lift height position calculated by the lift height position calculation means based on the calculation result of the wear amount calculation means.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a reach-type unmanned forklift will be described below with reference to FIGS. 1 to 9. As shown in FIG. 3, an electromagnetic guide line L through which a guidance signal flows is laid on the road between the storage station J where cargo is stored and the loading/unloading station K, and the driving path of the unmanned forklift 1 as an unmanned industrial vehicle is is formed. Mark plates 2 to 5 for instructing operation information to the unmanned forklift 1 are arranged at predetermined locations on the electromagnetic induction line L in front of both stations J and K and in the middle of both stations J and K.

The mark plates 2 to 5 are made by arranging marks made of iron plates or the like in various patterns.
Each type of operation information can be specified, and the unmanned forklift 1 can read the operation information on the mark plates 2 to 5 using a known method. In this embodiment, the operation information indicated by the mark plate 2 is operation information for causing the unmanned forklift 1 to spin turn, and the operation information indicated by the mark plate 3 is operation information for causing the unmanned forklift 1 to stop. This is operation information for carrying out cargo handling operations. A reference traveling section is formed between mark plate 4 and mark plate 5, which serve as indicating means, and these mark plates 4 and 5 serve as lift position calculation means and wear amount calculation means, which will be described later, in the reference travel section. It also instructs the microcomputer C, which serves as a correction means, to provide operation information for performing various calculations.

FIG. 2 shows a side view of the unmanned forklift 1. A pickup coil 8 for detecting the electromagnetic induction wire L is mounted on the underside of the forklift 1, and a mark plate is also installed on the underside of the forklift 1. 2
A mark plate sensor 9 is installed as a driving judgment means for detecting the speed of .about.5. A pair of masts 10 (only one of which is shown) provided at the front of the forklift 1 moves back and forth along a pair of leg portions 12 extending in the horizontal direction as the reach cylinder 11 expands and contracts. There is. The amount of movement of the mast 10 back and forth is determined by two limit switches 13a and 13b provided on the side of the reach cylinder 11.

The mast 10 is composed of an outer mast 10a and an inner mast 10b, and the inner mast 10b moves up and down as the lift cylinder 14 expands and contracts. A fork 16 is suspended and supported via a lift bracket 15 on a chain (not shown) that is hung from a chain wheel (not shown) rotatably attached to the inside of the inner mast 10b. As the inner mast 10b goes up and down, the lift bracket 15 moves up and down by the chain that is wound or unwound, and the fork 16 goes up and down.

Further, a rotary encoder 17 is attached to the inner side of the inner mast 10b and is connected to the chain wheel and serves as a lifting amount detecting means. Rotates as the wheel rotates,
The amount of elevation of the fork 16 is detected based on the amount of rotation.

Furthermore, a limit switch M is attached to the lower part of the outer mast 10a at a predetermined height position. The limit switch M is turned on and outputs a reset signal every time the lift bracket 15, which moves up and down, passes its mounting position. The reset signal is adapted to reset a count value X of a lifting height counter 25b, which will be described later.

Furthermore, a tilt cylinder 18 for tilting the fork 16 is provided at the rear of the lift bracket 15.
A potentiometer 19 is installed in the outer mast 10a to detect the tilt angle of the lift bracket 15 and fork 16, which are tilted by the expansion and contraction operations of the tilt cylinder 18. Inside the body of the forklift 1 are the cylinders 11, 14, 18.
A hydraulic control circuit for driving and controlling the cylinders is connected to each cylinder.
1, 14, 18, solenoid valves 11a, 14a,
18a is provided, and each cylinder 11,1
A cargo handling pump 20 that supplies hydraulic oil to the cargo handling pumps 4 and 18 and a cargo handling motor 21 that rotationally drives the cargo handling pump 20 are provided.

Furthermore, within the body of the forklift 1, a steering motor 22 and a traveling motor 23 for steering and rotating the driving wheels 6 are disposed. Then, the unmanned forklift 1 moves forward and backward by forward and reverse movement of the drive wheels 6 and the driven wheels 24 that follow, and inserts the forks 16 into the pallets P placed on the racks R of both stations J and K. The cargo W is transported along with the pallet P.

Next, the electrical configuration of the unmanned forklift 1 configured as described above will be explained based on FIG. 1. The microcomputer C is composed of a central processing unit (hereinafter referred to as CPU) 25, a travel controller 26, and a cargo handling controller 27, and a predetermined operation program is stored in the CPU 25. Also, the same CPU2
5 includes a travel controller 26 and a cargo handling controller 27
The travel controller 26 and the cargo handling controller 27 are controlled based on a travel program stored in the CPU 25.

The CPU 25 has built-in distance and lift counters 25a and 25b for counting pulses output from the travel rotary encoder 7 and the lift height rotary encoder 17, respectively. The CPU 25 also contains a reference travel distance U between the mark plate 4 and the mark plate 5, a number S of pulses output from the travel rotary encoder 7 in one rotation of the drive wheel 6,
The number of pulses (hereinafter referred to as the total number of reference pulses) N that is output from the driving rotary encoder 7 when the driving wheel 6 that is not worn out travels the reference travel distance U section.
0 is stored in advance.

Furthermore, the CPU 25 stores the insertion hole position PH from the bottom of the fork insertion hole (not shown) of the pallet P placed on the rack R of each of the stations J and K, and the drive position that is not worn out. The fork 16 is in the state of the wheel 6 and corresponds to the mounting position B from the floor of the limit switch M attached to the outer mast 10a and one pulse output from the rotary encoder 17 for lifting height.
A movement amount A is stored in advance.

The travel controller 26 includes a steering motor drive circuit 28 and a travel motor drive circuit 29.
Steering motor 22 and traveling motor 23 via
is connected, and the pickup coil 8
is connected. Then, based on the detection signal from the pickup coil 8, a detection signal to that effect is output to the steering motor drive circuit 28, and the steering motor drive circuit 28 drives and controls the steering motor 22.

A potentiometer 30 is connected to the steering motor 22, and when the steering motor 28 is driven, the potentiometer 30 detects the steering angle and outputs it to the travel controller 26.
6 performs feedback control of the steering angle based on the detection signal. Further, the traveling motor 23 is provided with the aforementioned traveling rotary encoder 7 as a rotation detection means.
is connected, and the traveling rotary encoder 7 detects the number of revolutions of the traveling motor 23 and sends a predetermined number of pulses S per revolution to the CPU 25 via the traveling controller 26 as the driving wheel 6 rotates. It is designed to output to a built-in distance counter 25a. Therefore, when the unmanned forklift 1 travels the standard travel distance U, the distance counter 25 is
The number of pulses input to a (hereinafter referred to as the total number of actual pulses) N
will change (increase) as the drive wheels 6 wear out.

On the other hand, the cargo handling controller 27 includes each electromagnetic valve 11a, 14a, 18a and a cargo handling motor 21.
is connected to switch and control the electromagnetic valves 11a, 14a, and 18a, as well as drive and control the cargo handling motor 21. Furthermore, limit switches 13a and 13b attached to the side of the reach cylinder 11 are connected to the cargo handling controller 27, and as the reach cylinder 11 moves forward, the mast 10 moves forward and the limit switch 13a is turned on. When the limit switch 13a is turned on, the limit switch 13a outputs an on signal to the cargo handling controller 27.

When the cargo handling controller 27 receives an ON signal from the limit switch 13a, it closes the reach electromagnetic valve 11a to stop the reach cylinder 11 from protruding. Further, when the mast 10 moves backward due to the contraction operation of the reach cylinder 11 and the limit switch 10b is turned on, an on signal is outputted from the limit switch 13b to the cargo handling controller 27.

When the cargo handling controller 27 receives an ON signal from the limit switch 13b, it closes the reach electromagnetic valve 11a and stops the contraction operation of the reach cylinder 11. Further, a lifting height rotary encoder 17 and a potentiometer 19 are connected to the cargo handling controller 27, and the lifting height rotary encoder 17 receives pulse numbers based on the amount of rotation of a chain wheel (not shown), which is built into the CPU 25 via the cargo handling controller 27. The output is output to the lift height counter 25b. The potentiometer 19 detects the inclination angle of the fork 16 and outputs the inclination angle signal to the cargo handling controller 27.

When the limit switch M connected to the cargo handling controller 27 is turned on, the limit switch M outputs a reset signal to the lifting height counter 25b via the cargo handling controller 27. When the lift height counter 25b receives a reset signal from the limit switch M, it resets the count value x of the pulses input from the lift height rotary encoder 17.

Therefore, the product (=AX) of the count value X of the lift height counter 25b and the movement amount A corresponding to the one pulse is
is the lift height position based on the mounting position B of the limit switch M. As a result, the height position of the fork 16 from the floor is "AX+B" in the case of the drive wheel 6 which is not worn out.
”. Further, a mark plate sensor 9 is connected to the cargo handling controller 27, and the mark plate sensor 9 detects the arrangement pattern of the mark plates 2 to 5 and outputs the detection signal to the cargo handling controller 27. . Then, the cargo handling controller 27 outputs the detection signal from the mark plate sensor 9 to the CPU 25, and the CPU 25 determines the operation information of the mark plates 2 to 5 based on the detection signal. The CPU 25 outputs a control signal to that effect to the travel controller 26 and cargo handling controller 27 based on the operation information.

[0026] The travel controller 26 includes a CPU 25.
When a control signal based on operation information is input from the drive circuit, a signal to that effect is output to each of the drive circuits 28 and 29 to drive and control the steering motor 22 and the travel motor 23. On the other hand, the cargo handling controller 27 is operated by the CPU 25.
When a control signal based on operation information is input from a control signal, a signal to that effect is output to each electromagnetic valve 11a, 14a, 18a and the cargo handling motor 21, and each electromagnetic valve 11a, 14a,
18a and the cargo handling motor 21 are driven and controlled.

When the mark plate sensor 9 detects the mark plate 4 and the mark plate 5,
The mark plate sensor 9 outputs a signal to that effect to the CPU 25 via the cargo handling controller 27. CPU25
When it is determined that the mark plate sensor 9 has detected the mark plate 4 and the mark plate 5, the total number N of actual pulses generated from the running rotary encoder 7 within the section from the mark plate 4 to the mark plate 5 is calculated from the distance counter 25a. The amount of wear D of the driving wheels 6 is calculated based on the read out and pre-stored reference pulse total number N0 and the like. Therefore, when the drive wheel 6 is worn out, the elevation position of the fork 10 from the floor is "
Ax+B-D".

Then, the CPU 25 determines the lift height position (=Ax+B−D) based on the wear amount D of the drive wheel 6, controls the lift cylinder 14, and moves the fork 16 up to the insertion hole position PH of the pallet P. It is designed to increase the Next, the operation of the unmanned forklift having the above configuration will be explained according to the flowchart of FIG. 4. In this embodiment, the operation when the unmanned forklift 1 travels from the storage station J to the loading/unloading station K will be described.

First, when the unmanned forklift 1 starts traveling along the electromagnetic induction line L, the CPU 25 executes step 1.
At 01, the mark plate sensor 9 detects the mark plate 4, and it is determined whether or not the detection signal is input to the travel controller 26. Then, when the CPU 25 determines that the detection signal of the mark plate 4 has been input to the traveling controller 26, the process proceeds to the next step 102. In step 102, the CPU 25 controls the distance counter 2.
5a from the driving rotary encoder 7 to the driving wheel 6.
Start counting the pulses generated by the rotation of .

In the next step 103, the CPU 25 determines whether or not the unmanned forklift 1 has traveled the reference travel distance U section, the mark plate sensor 9 has detected the mark plate 5, and the detection signal has been input to the travel controller 26. do. When the CPU 25 determines that the detection signal of the mark plate 5 has been input to the traveling controller 26, the process moves to the next step 104, and the distance counter 25a finishes counting the pulses.

[0031] Subsequently, in step 105, the CPU 2
5 is the total number N of actual pulses counted by the distance counter 25a and the reference number N of running pulses stored in advance.
0 and the number of running pulses S generated in one rotation of the drive wheel 6
Based on this, the wear amount D of the drive wheel 6 is calculated by the following predetermined calculation method. D=(U×S/2π)×(1/N0 -1/N) Next,
The CPU 25 calculates the amount of wear D calculated in step 105.
, the amount of movement A of the fork 16 corresponding to one pulse generated by the lift height rotary encoder 17, and the limit switch M.
Based on the mounting position B and the insertion hole position PH, the number of pulses when the fork 16 reaches the insertion hole position PH stored in advance in the CPU 25, that is, the target count value Xp of the lift height counter 25b, is calculated by the following calculation method. calculate.

PH = A×Xp + B−D∴Xp = (
PH -B+D)/A After the target count value Xp is calculated, the CPU 25
In step 106, it is determined whether mark plate 3 has been detected. When the mark plate 3 is detected, the CPU 25 outputs a signal for causing the unmanned forklift 1 to perform a spin turn to the travel controller 26 in step 107, and drives the steering motor 22 and the travel motor 23. Subsequently, after spin-turning the unmanned forklift 1, the CPU 25 moves to steps 108 and 109, detects the mark plate 2, and determines that the unmanned forklift 1 has arrived at the loading/unloading station K.

When the unmanned forklift 1 arrives at the loading/unloading station K, the CPU 25 controls the loading/unloading controller 27.
A signal for raising the fork 16 is output. The cargo handling controller 27 operates the lift cylinder 14 to project based on the signal, and raises the fork 16 to the insertion hole position PH. That is, when the limit switch M is turned on and the lifting height counter 25b is reset, the CPU 25 raises the fork 16 from the mounting position B of the limit switch M. And height counter 2
The count value X of 5b is the calculated target count value X
When p reaches, the fork 16 is stopped at that position (see FIG. 5).

Next, the cargo handling controller 27 opens the reach electromagnetic valve 11a, causes the reach cylinder 11 to project, and moves the mast 10 forward.
In this state, the CPU 25 causes the unmanned forklift 1 to travel forward (see FIG. 6). Then, the CPU 25 moves the unmanned forklift 1 further forward, inserts the fork 16 into the pallet P on which the cargo W is placed, and further raises the fork 16 (see FIG. 7).

[0035] Next, the CPU 25 executes the cargo handling controller 2.
While contracting the reach cylinder 11 by 7,
The unmanned forklift 1 is driven backwards, and the forks 16 are tilted while lowering them (see FIG. 9).
. Then, in this state, the vehicle continues traveling backwards and transports the cargo W to the storage station J, which is the destination. Note that the CPU 25 also performs the above control when placing the cargo W transported from the loading/unloading station K on the rack R of the storage station J. The reference running section at this time is the same as above, but the mark plate 5 serves as the instructing means to start counting the number of input pulses, and the mark plate 4 serves as the instructing means to end counting the number of input pulses. .

As described in detail above, according to the unmanned forklift 1, even if the drive wheels 6 are worn out, the amount of wear D is calculated, and the target count value Xp corresponding to the amount of wear D is calculated.
Calculate the fork 16 at the height of the insertion hole position PH.
Therefore, it is possible to prevent mistakes in cargo handling operations that would otherwise occur due to wear of the drive wheels 6 and lowering of the lifting height of the fork 16. Moreover, in this example,
Since the amount of wear D can be calculated while the vehicle is traveling, there is no need to stop the automatic guided vehicle forklift 1 or move the fork 16 up and down to correct the lifting height position. Therefore, it is possible to shorten the time required to carry out loading and unloading operations for the cargo W, thereby reducing operational costs.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and may be configured as follows, for example, without departing from the spirit of the invention. (1) In the above embodiment, the fork lifting position PH was calculated by detecting the wear amount D of the driving wheel 6 as a tire, but the fork lifting position PH was calculated by detecting the wear amount of the driven wheel 24.
may be calculated.

(2) In the above embodiment, the fork 16 is used as an attachment, but the fork 16 may be replaced by a bail clamp or the like that directly clamps and transports the load W from the left and right sides.

[0039]

As described in detail above, according to the present invention, it is possible to achieve the excellent effect of shortening the time required to carry out cargo loading and unloading operations.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the electrical configuration of an unmanned forklift truck according to an embodiment of the present invention.

FIG. 2 is a side view of an unmanned forklift.

FIG. 3 is a schematic plan view showing a travel route of an unmanned forklift.

FIG. 4 is a flowchart showing the operation of the microcomputer.

FIG. 5 is a side view of the unmanned forklift showing a state in which the unmanned forklift has arrived at the loading/unloading station and has started lifting its forks.

FIG. 6 is a side view of the unmanned forklift showing a state in which the reach cylinder is protruded and the mast is moved forward.

FIG. 7 is a side view of the unmanned forklift showing a state in which the fork is inserted into the pallet on which cargo is placed and the pallet is separated from the rack.

[Figure 8] While driving the unmanned forklift truck backwards, the fork is lowered while moving the mast backwards,
Furthermore, it is a side view of the unmanned forklift truck showing a state in which the forks are tilted.

9 is a side view of the unmanned forklift showing a state in which the fork is lowered while moving the mast further rearward than in the state shown in FIG. 8, and the unmanned forklift is traveling backwards.

[Explanation of symbols]

1... Unmanned forklift as an unmanned industrial vehicle, 4... Mark plate as indicating means, 5... Mark plate as indicating means, 6... Drive wheel as tire, 7... Rotary encoder for running as rotation amount detecting means, 9 ...Mark plate sensor as a traveling judgment means, 16.Fork as an attachment, 17.Rotary encoder for lifting height as a lifting amount detection means, C.Microcomputer as a lifting height position calculation means, wear amount calculation means and correction means. .

Claims (1)

[Claims] 1. Lifting amount detection means for detecting the lifting amount of an attachment in an unmanned industrial vehicle; lifting height position calculation means for calculating the lifting height position of the attachment based on a detection signal of the lifting amount detection means; A rotation amount detection means for detecting the amount of rotation, a travel judgment means for detecting an indicating means indicating a predetermined reference distance and determining whether the reference distance has been traveled, based on the rotation amount detection means and the travel judgment means. A lift in an unmanned industrial vehicle comprising: a wear amount calculating means for calculating the amount of tire wear based on the wear amount calculating means; and a correction means for correcting the lifting height position calculated by the lifting height position calculating means based on the calculation result of the wear amount calculating means. High position correction device.