JPH0794320B2 - Automatic cargo handling control method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a cargo handling control method for an automatic guided vehicle that travels with a load on a pallet loaded by a fork.

(Prior Art) In the conventional cargo handling control method for an automated guided vehicle, the position of the fork is controlled by a sensor provided on the vehicle body.

(Problems to be Solved by the Invention) In the conventional cargo handling control method as described above, since the unloading operation is performed by ignoring the relative position deviation and angle deviation between the pallet and the fork, the load before unloading is There is a problem that if it is not installed at a predetermined position on the ground with high accuracy, it cannot be loaded at a predetermined position on the automatic guided vehicle with high accuracy. There is a problem in that the load cannot be accurately unloaded to a predetermined position on the ground, and the efficiency of the cargo handling work is reduced.

(Means for Solving the Problem) In order to eliminate these drawbacks, the present invention provides, in the first invention, a load on a pallet having a known width dimension placed at a known height and a fork. In an automated guided vehicle that is loaded on a vehicle and travels, the cargo handling mechanism includes a reach mechanism that moves the fork back and forth, a side shift mechanism that moves the fork left and right, a lift mechanism that moves the fork up and down, and these mechanisms as a whole. A turntable mechanism that rotates about an axis perpendicular to the vehicle body is provided, and an optical distance measuring device that detects the distance to the front load is attached to the tip of each of the pair of left and right forks. By comparing the height of the memorized load with the current fork height, the optical distance measuring device at the tip of the left and right forks can be adjusted to the height at which the reflected light from the pallet enters the optical distance measuring device. The first process of vertically moving the fork by the lift mechanism, and the second process of horizontally moving the fork by the side shift mechanism until the reflected light from the pallet enters the left and right of the optical distance measuring device. The distance between the left and right sides of the optical distance measuring device and the pallet is detected, and the relative inclination between the pallet and the fork is calculated from the detected value and the left and right mounting distances of the optical distance measuring device stored in advance. The third process of rotating the fork by the turntable mechanism until the tilt becomes zero, and the boundary between the state where the reflected light from the pallet is incident and the state where it is not incident on either the left or right side of the optical distance measuring device. The fourth process of moving the fork left and right by the side shift mechanism until it faces the left and right edges of the pallet, which is the position, Set the target position of the fork to face the regular insertion position of the pallet based on the required horizontal movement distance of the fork to face the regular insertion position of the pallet and the current left and right movement position of the fork, and move the fork until the target position moves. 5th to move left and right by side shift mechanism
And the sixth process in which the fork is lowered by the lift mechanism until the pallet reflected light is not received by the optical distance measuring device and the fork faces the pallet insertion opening, and the fork is reached by the reach mechanism and the lift mechanism. In the second invention, an unmanned guided vehicle is adopted in which, after the load is loaded on the fork, it is moved back and forth and up and down, and then the seventh processing is performed to return all the cargo handling mechanisms to the original origin position. If the vehicle body is steered by the difference in the rotational speed of the left and right driving wheels, a control method for turning the automatic guided vehicle itself on the spot by the rotational speed difference between the left and right driving wheels without providing the turntable mechanism is provided. Is adopted to solve the above problems.

(Embodiment) FIG. 1 is a first embodiment of a vehicle body structure of an automated guided vehicle to which the present invention is applied. 1 is a vehicle body, 2 is a fork, 3 is an optical distance measuring device attached to the tip of the fork 2. is there. The fork 2 includes a reach mechanism 7, a side shift mechanism 8, and a lift mechanism 9, which are well-known techniques, as shown in FIG.
It can be moved up and down and these mechanisms are on a turntable mechanism 10 which is well known in the art and can be rotated as shown. The side shift mechanism 8, the lift mechanism 9, and the turntable mechanism 10 are provided with potentiometers, encoders and the like (not shown) for detecting the moving position of each mechanism. The optical distance measuring device 3 is composed of a light projecting section, a light receiving section and a computing section via a lens system. In the light receiving section, the light projected from the light projecting section is reflected by a load located in front and This is an existing device in which light is received by a one-dimensional optical sensor, a light receiving position is detected, and a distance from a light receiving position in front of the light receiving position in a calculation unit is calculated.

FIG. 2 is a second view of the body structure of an automated guided vehicle to which the present invention is applied.
In the embodiment, reference numeral 4 denotes the left and right driving wheels of the vehicle body 1, and the vehicle body 1 steers by the difference in the rotational speeds of the left and right driving wheels 4. Therefore, the first
It is not necessary to provide a turntable mechanism as shown in the figure.
It is possible to perform a rotation operation equivalent to that of the turntable function 10 in the figure. The left and right drive wheels 4 are provided with an encoder or the like (not shown) for detecting each rolling distance,
The above rotational position is calculated from the detected rolling distances. Other functions are the same as those of the first embodiment shown in FIG.

FIG. 3 is a flowchart showing a processing procedure of a cargo handling control method for an automatic guided vehicle according to the present invention. FIG. 4 is an operation state diagram of the fork with respect to the pallet in the process of the cargo handling control method of the present invention. The cargo handling control method of the present invention will be described in detail with reference to Figs. 3 and 4. Fig. 3 (a) shows a first process for detecting the upper and lower equal positions of the fork 2 and a load stored in advance. Is moved up and down by the lift mechanism 9 until the heights of the forks 2 coincide with each other. By this process, the height of the fork 2 is reflected by the optical distance measuring device 3 from the pallet 5 as shown in FIG. It is the height at which the light enters.

FIG. 3 (b) is a process of moving the fork 2 left and right by the side shift mechanism 8 as a second process until the reflected light from the pallet 5 enters the left and right of the optical distance measuring device 3. By this process, the optical distance measuring device 3 can detect the distance between the left and right sides of the pallet 5 as shown in FIG. 4 (b). FIG. 3C shows the distance between the pallet 5 and each of the left and right sides of the optical distance measuring device 3 as the processing of FIG. 3, and the detected value and the optical distance measuring device 3 stored in advance.
The relative inclination between the pallet 5 and the fork 2 is obtained from the left and right mounting intervals of the vehicle body 1 until the inclination becomes zero due to the rotation speed difference of the turntable mechanism 10 or the left and right drive wheels 4.
This is a process of rotating the fork 2 by turning itself on the spot, and this process causes the pallet 5 to move as shown in FIG. 4 (c).
And fork 2 can be parallel.

In FIG. 3D, as the fourth processing, one of the left and right sides of the optical distance measuring device 3 faces the left and right edges of the pallet 5 which is the boundary position where the reflected light from the pallet 5 is incident. In the process of moving the fork 2 to the left or right by the side shift mechanism 8, the left or right of the fork 2 faces the left or right edge of the pallet 5 as shown in FIG.

FIG. 3E shows a required horizontal movement distance of the fork 2 from the state of facing the right and left edges of the pallet 5 stored in advance as the fifth process to the facing of the regular insertion position of the pallet 5 and the fork 2. Fork 2 for facing the regular insertion position of the pallet 5 from the current left-right movement position
The process of moving the fork 2 to the left and right by the side shift mechanism 8 until the target position is determined and the target position is moved to
By this processing, the fork 2 faces the regular insertion position of the pallet 5 as shown in FIG.

FIG. 3 (f) is a process of lowering the fork 2 by the lift mechanism 9 as the sixth process until the reflected light from the pallet 5 is no longer incident on the optical distance measuring device 3. Fork 2 is pallet 5 as in (f)
Face the insertion slot of. 3 (g), the fork 2 is moved forward and backward and up and down by the reach mechanism 7 and the lift mechanism 9 as the seventh process, and after the load is loaded on the fork 2,
By the process of returning all the cargo handling mechanisms to the original origin position, the load is accurately loaded on the predetermined position of the vehicle body 1 by this process.

The processes shown in FIGS. 3A to 3G are performed by a computer or the like (not shown) mounted on the vehicle body 1.

(Advantages of the Invention) As described above, since it is the cargo handling control method in which the relative positional deviation and angular deviation between the pallet and the fork are corrected during the unloading operation, the pallet is loaded on the automatic guided vehicle. Produce the effect of.

There is an advantage that the load can be accurately loaded at a predetermined position on the automatic guided vehicle even if the load before unloading is not precisely installed at the predetermined position on the ground. Even when it is lowered to the ground, it can be accurately lowered to a predetermined position on the ground.

Since the eccentric load does not act on the fork, there is little damage to the vehicle and smooth cargo handling work can be performed.

[Brief description of drawings]

1 (a) and 1 (b) are a side view and a front view showing a first embodiment of a vehicle body structure of an automated guided vehicle adopting the present invention, and FIGS. 2 (a) and 2 (b) adopting the present invention. FIG. 3 is a side view and a front view showing a second embodiment of the body structure of an automated guided vehicle, and FIG. 3 is a flowchart showing a cargo handling control method for the automated guided vehicle according to the present invention;
FIG. 4 is an operation state diagram of the fork with respect to the pallet in the process of cargo handling control of the present invention. 1 ... Vehicle body, 7 ... Reach mechanism 2 ... Fork, 8 ... Side shift mechanism 3 ... Optical distance measuring device, 9 ... Lift mechanism 4 ... Left and right drive wheels, 10 ... Turntable mechanism 5 ... …palette

Claims (2)

[Claims] 1. A reach for moving a fork back and forth as a cargo handling mechanism in an automated guided vehicle in which a load on a pallet having a known width dimension placed at a known height is loaded on the vehicle by a fork and traveling. A mechanism, a side shift mechanism for moving the fork to the left and right, a lift mechanism for moving the fork up and down, and a turntable mechanism for rotating the entire mechanism around an axis vertical to the vehicle body are provided, and the tips of the pair of left and right forks are provided. An optical distance measuring device that detects the distance to the front load is attached to the front of the left and right forks by comparing the height of the load stored in advance with the current fork height during the load pickup operation. For the first process of moving the fork up and down by the lift mechanism to the height at which the reflected light from the pallet enters the distance measuring device, and for both the left and right sides of the optical distance measuring device. The second process of moving the fork left and right by the side shift mechanism until the reflected light from the let enters the state, and the distance between the left and right of the optical distance measuring device and the pallet is detected, and the detected value and the The third process of rotating the fork by the turntable mechanism until the relative inclination between the pallet and the fork is calculated from the stored left and right mounting distances of the optical distance measuring device and the optical distance measuring device. A fourth process in which the fork is moved left and right by the side shift mechanism until one of the left and right sides of the device faces the left and right edges of the pallet, which is the boundary position between the state where the reflected light from the pallet enters and the state where the reflected light does not enter the pallet. And the required left and right movement distance of the fork from the state of facing the left and right edges of the pallet stored in advance to the face of the regular insertion position of the pallet. Statutes the current fork target position for facing the right and left movement position normal insertion position of the pallet from, fifth to lateral movement of the forks by a side shift mechanism until the moving object thereof located
And the sixth process in which the fork is lowered by the lift mechanism until the pallet reflected light is not received by the optical distance measuring device and the fork faces the pallet insertion opening, and the fork is reached by the reach mechanism and the lift mechanism. A cargo handling control method for an automated guided vehicle, which comprises performing a seventh process of moving all the cargo handling mechanisms back to their original origin positions after the cargo is loaded on a fork by moving back and forth and up and down. 2. In the case where the automatic guided vehicle is a vehicle body steered by the rotational speed difference between the left and right driving wheels, a turntable mechanism is not provided,
The cargo handling control method for an automatic guided vehicle according to claim 1, wherein the automatic guided vehicle itself is rotated in-situ in the rotation operation of the third processing by the difference in the rotational speeds of the left and right driving wheels.