JPH0431127B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <<Industrial Application Field>> The present invention relates to a positioning device for an automatic guided vehicle that is capable of accurately stacking or unloading loads even when a loading platform is curved.

<<Prior art and its problems>> As a conventional positioning device for an automatic guided vehicle, the one described in, for example, Japanese Patent Publication No. 59-355135 is known.

However, with such conventional equipment,
Contact detectors installed on the left and right sides of the front end of the conveyance vehicle were configured to stop the vehicle only when both of them were turned on, so if the loading platform was bent with respect to the front of the conveyance vehicle, Even if one of the contact detectors turned on, the vehicle continued to move forward until the other contact detector turned on, and there was a risk that the cargo would eventually collapse.

On the other hand, in order to solve this problem, if the vehicle is configured to stop only when one of the contact detectors is turned on, it is possible to prevent the cargo from collapsing due to forward pressure. There is a problem that loading and unloading operations cannot be carried out at all, making it impossible to put it to practical use.

<<Objective of the Invention>> The object of the present invention is to prevent the transport vehicle from forcibly pushing the transport platform, even if the transport platform is bent, and to ensure that the cargo is accurately loaded or unloaded onto the transport platform. An object of the present invention is to provide a positioning device for an automatic guided vehicle that can perform automatic guided vehicle positioning.

≪Structure of the invention≫ Referring to the claim correspondence diagram in FIG.
The configuration of the invention will be explained.

The left contact detector a and the right contact detector b are independently provided on the left and right sides of the front end of the carrier, and are supported so that they can be moved backward by the reaction force when they come into contact with an object in front of them.

The straight distance measuring means c starts measurement in response to a contact detection output from either the left or right contact detectors a and b.

When a contact detection output is obtained from the other contact detector before the measured distance reaches a permissible value, the stop timing control means d issues a stop command in response to the contact detection output, and controls the measured distance. If a contact detection output is not obtained from the other contact detector even if the contact detection output reaches the allowable value, a stop command is issued when the contact detector reaches the allowable value.

Next, the configuration of the second invention of the present application will be explained with reference to the claim correspondence diagram of FIG.

The left contact detector e and the right contact detector f are independently provided on the left and right sides of the front end of the carrier.

The turning transition control means g stops the rotation of the contact detection side drive wheel in response to the contact detection output of either the left or right contact detectors e, f, and causes the contact detection side drive wheel to shift to a turning operation.

The turning angle measuring means h starts measurement at the time of transition to the turning operation.

When a contact detection output is obtained from the other contact detector before the measured angle reaches the allowable value, the stop timing control means i issues a stop command in response to the contact detection output, and controls the measured angle. If a contact detection output is not obtained from the other contact detector even if the contact detection output reaches the allowable value, a stop command is issued when the contact detector reaches the allowable value.

<<Description of Embodiment>> FIG. 3 schematically shows the configuration of an automatic guided vehicle according to a first embodiment of the present invention. As shown in the figure, this automatic guided vehicle 1 is equipped with left and right drive wheels 4 and 5 that are driven independently via motors 2 and 3, and is driven along a guide line buried in the road surface (not shown). It is equipped with an automatic steering mechanism for driving.

Furthermore, independent contact detectors 7 and 8 are attached to the left and right sides of the front end of the vehicle body 6, respectively.

When these contact detectors 7 and 8 come into contact with a loading platform or the like while moving forward, they immediately detect this and emit a predetermined detection output, and then the contact detectors 7 and 8 detect it immediately and emit a predetermined detection output. Retractably supported.

Some examples of specific structures of contact detectors are shown in the fourth section.
As shown in Fig. 5.

The contact detector shown in FIG. 4 has a limit switch 9 mounted on the front of the vehicle body 6, and a contact detection plate 11 mounted in front of the limit switch 9 via a return spring 10.
The limit switch 9 is pressed into operation via a protective spring 12 of appropriate strength attached to the back surface of the contact detection plate 11.

That is, from the state in which there is no object in front as shown in FIG. 4A, the contact detection plate 11 changes as shown in FIG.
When the contact detection plate 11 comes into contact with an object in front of it, the limit switch 9 is pressed through the protection spring 12, and the contact detection plate 11 moves back against the force of the return spring 10, and at the time when it moves back by the distance shown in FIG. The protection spring 12 is compressed to its limit position to protect the limit switch 9 from overload.

In the case of the contact detector shown in FIG. 5, a contact detection arm 13 is swingably supported at the front end of the vehicle body 6 via a spring 14, and a limit switch 15 attached to the base of this arm 13 is connected to the arm 1.
The pressing operation is performed by a cam 16 that is interlocked with 3.

That is, when the arm 13 changes from the state in which there is no object in front as shown in FIG. 5A to the state in which the arm 13 is in contact with the object in front as shown in FIG. continues to be pressed via the cam 16. Then, as shown in Figure C, the arm 13 is
In the retracted state, the spring 14 is stretched to its limit and is in a tight state.

Next, FIG. 6 is a block diagram showing the electrical hardware configuration of the device according to the first embodiment of the present invention.

As shown in the figure, this device is mainly composed of a microcomputer 17, and the above-mentioned left side,
A left and right wheel pulse generator 1 reads the output from the right side contact detectors 7 and 8 and simultaneously generates a pulse train corresponding to the rotational speed of the left and right wheels 4 and 5.
8 and 19, and execute the flowchart of FIG. 7, which will be described later, to appropriately drive and control the left wheel motor 2 and right wheel motor 3 via the left wheel drive circuit and right wheel drive circuit 20, 21. It is something.

In addition, 22 is various detectors used for cargo handling, travel control, etc., 23 is a cargo handling equipment drive circuit, and 24 is cargo handling equipment.

Next, the operation of the apparatus according to the first embodiment of the present invention will be systematically explained with reference to the flowchart shown in FIG.

Until reaching the target cargo handling point, the right side contact detector 8 and the left side contact detector 7
The operating status of the device is checked repeatedly (step
100, 200).

In this state, if the contact detector 8 on the right side is
Assuming that is turned on (step 100 affirmative), in response to this, measurement of the forward travel distance is started (step 101).

This method of measuring the straight traveling distance is performed by measuring pulses based on signals from either the left wheel pulse generator 18 or the right wheel pulse generator 19 and calculating distance data.

If the left side contact detector is turned on before the straight travel distance determined in this way reaches the predetermined allowable distance (step 102 is affirmative), the left and right wheels are immediately Braking is applied to motors 2 and 3, and the unmanned guided vehicle stops.

On the other hand, if the left side contact detector 7 does not turn on even when the allowable value is reached (step 103 affirmative), it is determined that the loading platform or transport vehicle is significantly bent, and the vehicle remains as it is. (Step 400).

On the other hand, if the left side contact detector 7 turns on while reaching the target cargo handling point (step 200 affirmative), the same process as the right side is performed (steps 201 to 203, 300, 400). ).

Therefore, as shown in FIG. 8A, if the loading platform 25 is slightly bent relative to the vehicle (the degree of bending is within the allowable range), if one of the contact detectors turns on. However, the vehicle continues to move forward, stops at a position substantially directly facing the cargo platform 25, and issues a positioning completion command to the cargo handling equipment drive circuit 23, thereby allowing subsequent cargo handling operations to be carried out without any hindrance.

On the other hand, as shown in FIG. 8B, if the loading platform 25 is significantly curved relative to the vehicle, the vehicle will stop at a position that has moved forward by the distance, and a command will be sent to the cargo handling equipment drive circuit 23. cargo handling operations will be prohibited from now on. For this reason, it is possible to prevent the transport vehicle from forcibly pushing the cargo platform 25 in a bent state, or to carry out the loading operation without causing the cargo to collapse.

Next, FIG. 9 is a flowchart showing the software configuration of a second embodiment of the present invention, and since the hardware configuration of this embodiment is the same as that of FIG. 6, a description thereof will be omitted.

Similar to the first embodiment, the feature of this second embodiment is that when either one of the contact detectors is turned on, the vehicle does not stop immediately, but turns until it is directly facing the loading platform. The purpose is to prohibit further loading and unloading operations only when the vehicle turns at an angle and does not directly face the loading platform.

That is, as in the first embodiment, the operating states of the left and right contact detectors 7, 8 are repeatedly checked by the microcomputer until the target cargo handling point is reached (steps 500, 600).

In this state, if the contact detector 8 on the right side is
Assuming that is turned on, the right wheel is immediately braked (step 501), the vehicle starts turning to the right, and at the same time, the turning angle θ is indirectly measured by the number of rotations of the left wheel. (Step 502).

If the left side contact detector 7 is turned on as shown in FIG. 10A before this turning angle θ reaches the allowable turning angle θ, braking is also applied to the left wheel in the same manner as in the first embodiment. is applied, and the positioning work is completed (step 700).

On the other hand, if the left side contact detector 7 reaches the allowable turning angle without operating while the vehicle is turning as shown in FIG. 10B (step 504 is affirmative),
It is determined that there is an obstacle or the loading platform is significantly curved, and the left wheel is also braked, prohibiting further loading and unloading operations, and similarly to the first embodiment, preventing cargo from collapsing due to incorrect loading. will be done.

On the other hand, when the left side contact detector is turned on while reaching the destination, similar operations are performed (steps 601 to 604, 700, and 800).

According to this second embodiment, when the loading platform is bent at an angle within the permissible range with respect to the vehicle body (see FIG. 10A), the vehicle body is directly facing the loading platform at the final turning position. Therefore, loading and unloading operations can be carried out with higher accuracy than in the first embodiment.

In addition, in this second embodiment, by setting the allowable turning angle θ large, it is possible to always position the vehicle in a position directly facing the loading platform even when the loading platform has a large curvature. You can carry out cargo handling operations such as:

<<Effects of the Invention>> As is clear from the description of each of the embodiments above, according to the present invention, when the loading platform etc. is curved with respect to the guide vehicle, the degree of the curve can be kept within the permissible range. If the load is bent, normal cargo handling work can be carried out, and if the degree of bending exceeds the allowable range, this will be detected and the transport vehicle will not be able to forcefully push the cargo platform, etc. This prevents loading and unloading operations from occurring and prevents cargo from collapsing in the future.

[Brief explanation of drawings]

Figure 1 is a claim correspondence diagram showing the configuration of the first invention of the present application, Figure 2 is a claim correspondence diagram showing the configuration of the second invention, and Figure 3 is a diagram showing the configuration of an automatic guided vehicle according to the first embodiment of the present invention. The schematic diagram, FIGS. 4 and 5 are diagrams each showing an example of the structure of a contact detector, FIG. 6 is a block diagram showing the electrical hardware configuration of the device according to the first embodiment of the present invention, and FIG. 8 is an explanatory diagram illustrating the operation of the device of the first embodiment. FIG. 9 is a flowchart showing the software configuration of the device of the second embodiment.
FIG. 0 is an explanatory diagram illustrating the operation of the device of the second embodiment. a, e... Left side contact detector, b, f... Right side contact detector, c... Straight travel distance measuring means, d, i... Stopping timing control means, g... Turning transition control means, k... Turning angle measuring means.

Claims (1)

[Scope of Claims] 1. Left and right contact detectors that are independently provided on the left and right sides of the front end of the conveyance vehicle and supported so that they can be retreated by the reaction force when they come into contact with an object in front of them; the left and right contact detectors; a straight distance measuring means that starts measurement in response to a contact detection output from one of the contact detectors; a contact detection output is obtained from the other contact detector before the measured distance reaches a tolerance value; Sometimes, a stop command is issued in response to the contact detection output, and if a contact detection output is not obtained from the other contact detector even if the measured distance reaches the tolerance value, the vehicle stops when the tolerance value is reached. A positioning device for an automatic guided vehicle, comprising a stop timing control means for issuing a command. 2. Left and right panels independently installed on the left and right sides of the front end of the transport vehicle
a right contact detector; a turning transition control means for stopping the rotation of the contact detection side drive wheel and shifting to a turning operation in response to a contact detection output of either the left or right contact detector; and; a turning angle measuring means that starts measurement at the time of transition to the turning operation; and when a contact detection output is obtained from the other contact detector before the measurement angle reaches an allowable value, the contact detection output is A stop timing control that issues a stop command in response to the above-mentioned measurement angle, and when a contact detection output is not obtained from the other contact detector even if the measured angle reaches an allowable value, issues a stop command when the above-mentioned allowable value is reached. A positioning device for an automatic guided vehicle, comprising: means.