JPH0338704A - Unmanned carrier and its drive control method - Google Patents

Abstract

PURPOSE:To increase the number of unmanned carriers driven on a driving route by switching the drive mode to a following vehicle mode in order to shorten the distance between the preceding and following vehicles. CONSTITUTION:For instance, the distance between an unmanned vehicle and an object is set at >=2m in a normal drive mode and the distance between vehicles is set at 40cm and 60cm in a co-drive mode. The vehicles (a) - (c) entered a common driving route from each joint route arrive at a point B and stops there temporarily in that order. A control CPU 23 counts the number of vehicles and designates a preceding vehicle to the carrier (a) having the count value '1' and then designates the following vehicles (b) and (c). An ultrasonic sensor is switched to an inter-vehicle mode from an anti-object mode and the distance between vehicles (b) and (c) is shortened (following vehicle mode). When a preceding vehicle start OK signal is transmitted from the CPU 23, the vehicles (a) - (c) are driven together on a common driving route (a) at a prescribed speed. As a result, the inter-vehicle distance can be shortened and therefore the number of running vehicles can be increased on a driving route.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an automatic guided vehicle that transports cargo along a predetermined travel route and a method of controlling the travel thereof.

2. Description of the Related Art A conventional automated guided vehicle travels along a predetermined route while detecting the presence or absence of an object within approximately 2 m in front of it using an object-to-object distance detection means, and if no object is detected, it continues to run at a normal speed of approximately 60 m/min. The vehicle is configured to decelerate or stop if an object is detected.

In addition, conventional travel control methods for travel routes with multiple starting points and destinations involve programming each automatic guided vehicle with a predetermined travel route from a specific starting point to a specific destination via a common travel route. It is being done.

Problems to be solved by the invention When a large number of such automatic guided vehicles are operated,
The vehicles will travel in a daisy chain along the travel route with a distance of approximately 2 meters between vehicles. Therefore, with conventional automatic guided vehicles, it is no longer possible to increase the number of vehicles running.

In addition, if a person crosses the travel route while the automated guided vehicle is running in a daisy chain state, the automated guided vehicle will immediately detect this and decelerate or stop, so the following automated guided vehicle will also slow down or stop. As a result of being forced into a stopped state, even if the initial deceleration or stopped vehicle restarts, it takes a considerable amount of time for the entire restart to be completed, making it difficult for the automatic guided vehicle to run smoothly. arise.

A first object of the present invention is to provide an automatic guided vehicle that can increase the number of vehicles traveling on a travel route and that can secure a crossing space on the travel route without disturbing smooth travel.

A second object of the present invention is to provide a travel control method that achieves the first object and allows automated guided vehicles to travel cooperatively or normally with less effort and to improve travel availability.

Means for Solving the Problems In order to achieve the first object, the present invention provides an object-to-object distance detection means for detecting an object-to-object distance and outputting a distance signal, and a traveling device for controlling a traveling speed according to the distance signal. The vehicle is characterized by comprising a speed control means and a switching means for switching the traveling speed control means between a following vehicle mode that reduces the following distance to the preceding vehicle and a leading vehicle mode that increases the following distance to the preceding vehicle. The purpose of this project is to provide an unmanned guided vehicle.

In order to achieve the second object, the present invention divides the entire driving route, sets driving sections, sets a mode for each driving section, and reduces the distance between the vehicle and the preceding vehicle by the following vehicle mode. The automatic guided vehicle having the above configuration is characterized in that a traveling group is formed and the vehicle travels in a coordinated manner, and the distance between the vehicles and the preceding vehicle is increased in a leading vehicle mode, thereby canceling the traveling group and causing the automatic guided vehicle to travel normally. The present invention provides a control method.

Function According to the automatic guided vehicle of the present invention, by switching to the following vehicle mode and shortening the inter-vehicle distance to the preceding vehicle, it is possible to increase the number of vehicles traveling on the travel route.

In addition, if the number of vehicles traveling is approximately the same, the mode is set to the leading vehicle mode for each number of vehicles as appropriate, and by making the leading vehicle and the following vehicle travel cooperatively as a group, sufficient cross-traversal space is created between the groups. Therefore, when a person crosses between groups, it is possible to avoid a situation where the automatic guided vehicle is unnecessarily slowed down or stopped, and it is possible to make the automatic guided vehicle run smoothly.

According to the traveling control method for an automatic guided vehicle of the present invention having the above configuration, by setting the mode for each traveling section, group reorganization such as forming or canceling a group or separating only specific vehicles can be performed individually. This can be done during the driving section.

Therefore, by setting traveling sections for multiple automatic guided vehicles, for example, by merging points from each starting point or branching points to each destination, automatic guided vehicles from different starting points can be connected to a common traveling section with a shortened inter-vehicle distance. The operating efficiency of each automatic guided vehicle can be improved with little effort, such as by making the group travel in a group at a branch point, and then discontinuing the group at a branch point and allowing the group to travel normally toward its respective destination.

Embodiment An automatic guided vehicle according to an embodiment of the present invention is shown in FIGS. 1 to 3.
This will be explained based on the diagram.

On the lower side of the inverted T-shaped vehicle body 1, a front wheel 2 and a pair of left and right rear wheels 3.3 are rotatably supported around a horizontal axis by respective brackets 4.5. Each bracket 4.5 is mounted on the vehicle body l so as to be rotatable about a vertical axis. A drive motor (not shown) is attached to these front wheels 2 and rear wheels 3. The front wheel 2 is attached to the bracket 4
It is rotated around a vertical axis by a front wheel steering drive pulley 7 via a timing heald 6 wound around the front wheel. This timing belt 6 is also wound around a front wheel steering angle detection pulley 8. The bracket 5 of the rear wheel 3 is connected to the tip of the rod of the rear wheel steering drive means 9 that expands and contracts the pair of left and right wheels, and is rotated about a vertical axis. A steering angle detection device 10 is attached to each bracket 5. A power source 11 for supplying electric power to the drive motor is installed near the rear wheel steering drive means 9, and a charging device 12 used to charge the electric fX 11 is installed in an example part of the vehicle body 1. ing.

A connecting portion 14 to a conveyed vehicle 13 on which an object is placed is provided in the front part of the front wheel 2. Between the connecting part ■4 and the front wheel 2, this automatic guided vehicle is connected to the guided vehicle 1.
A sensor 15 for detecting the position of the general transportation vehicle 13 when it sneaks into the lower surface of the vehicle 3, and a route detection sensor 16 for detecting the traveling route are provided. At the front end of the vehicle body 1, there is an ultrasonic sensor 1 that detects the distance between vehicles or the distance between objects.
7 are arranged. Direction indicator lamps 18 are installed on both sides of the ultrasonic sensor 17.

A control section 19 is provided on one side of the vehicle body 1 to control each device. In addition, 20 is a transmitting/receiving unit for optical communication with an external management CPU 23 (see FIG. 4), and 21
2 is a remote control signal input section used for manual remote control operation, and 22 is an emergency stop button. This emergency stop button 22 is used to temporarily stop the transport vehicle and release the group.

The ultrasonic sensor 17 used in the automatic guided vehicle of this embodiment receives the emitted ultrasonic wave reflected by the target object through a speaker, and the time period from the time of emission to reception is set to a timer period ΔT.
The distance to the object is obtained by the following equation.

(However, Va: the speed of sound) In this embodiment, when maintaining the inter-vehicle distance, the number of sampling times n is determined as shown in the following table.

A control method for causing a plurality of automatic guided vehicles configured as described above to travel along respective predetermined travel routes shown in FIG. 4 will be described next.

Three automatic guided vehicles No., a, No. b, No. and c merge from their respective starting points via each merging route and arrive at the first
After traveling along the next common traveling route (a), only the automatic guided vehicle No. a is guided to the branch route, and on the second common traveling route (b), a new automatic guided vehicle with automatic guided vehicle No. b as the leading vehicle is guided. A case will be explained in which the vehicles are reorganized into a group and travel as a group again.

First, the procedure from group formation to group departure will be explained with reference to the flowchart of the procedure in the management CPU 23 shown in FIG. explain. In this embodiment, the distance between objects during normal driving is set to 2 m or more, and the distance between vehicles during cooperative driving is set to 40 to 60 cm.

Transport vehicle No. that entered the common travel route from each merging route,
A to c send a standby signal to the management CPU 23 at point A, and, for example, reach point B in this order and temporarily stop. The management CPU 23 receives the standby signal, counts the number of vehicles, and designates a leading vehicle for the guided vehicle No. a whose count value is "1". If the count value is not ``1'', it is determined whether the count value is ``2'' or not, and subsequent vehicles are designated in sequence.

The designated leading vehicle No. a waits for a start signal from the management CPU 23, and the following guided vehicles No. b, N
o and c switch the ultrasonic sensor 17 from the object to the inter-vehicle distance to shorten the inter-vehicle distance.

When the leading vehicle start OK signal is sent from the management CPU 23, the guided vehicle No. a starts and the following guided vehicle N11b, N
The group travels along the primary common travel route (A) at a predetermined speed with vehicles o and c.

Control procedure for automatic guided vehicles No. and B when traveling in the first common travel section (A) from point 0 where the branch route branches and the second common travel section from point 0 to point D (B) will be explained with reference to the flowchart in FIG.

In the first common driving section (A), the leading vehicle No.

If the distance between the vehicle and the vehicle a is at least (50+10) cm, the vehicle slows down to shorten the distance, and if the distance is less than (50-10) cm and at least (50-10) cm, the vehicle continues to travel as specified. If it is less than (50-10), the vehicle speed is slowed down and the following distance is increased.

When the first common travel section (a) ends at point 0, the preceding vehicle No. a enters the branch route according to its own program. On the other hand, guided vehicle No. b, which has newly become the leading vehicle in the second common travel section (a), switches the ultrasonic sensor 17 from the inter-vehicle distance to the object distance and performs a predetermined travel. If it reaches the specified stopping position, it will stop and end, but if it has not arrived, it will sequentially judge whether the object distance is less than 50 cm, less than 1 m, and less than 2 m, and finally it will be 2 m.
Slowdown control is performed as necessary to ensure the above-mentioned distance between objects.

Therefore, in this traveling section (a), when a person crosses the traveling route, the crossing point is 2 immediately before transport vehicle No. b.
If it is within 50 cm, slow down control is performed, and if it is within 50 cm, it is stopped.

The present invention can be configured in various ways other than those shown in the above embodiments.

For example, the specific configuration of the automatic guided vehicle, including the object distance detection means and the number thereof, can be appropriately adapted to known techniques. Further, the numerical value of the distance between objects, the setting of the running route and the running section, etc. are not limited to those shown in the above embodiments, and can be appropriately designed as necessary. Furthermore, it goes without saying that the present invention can be implemented using not only optical communication but also wireless communication between the management CPU and the automatic guided vehicle.

Effects of the Invention According to the automatic guided vehicle of the present invention, since the inter-vehicle distance can be shortened, the number of vehicles traveling on the travel route can be increased, and by making multiple vehicles travel cooperatively,
It is possible to secure space between groups for people to cross.

Further, according to the automatic guided vehicle travel control method of the present invention, it is possible to easily cause multiple automatic guided vehicles to travel in a group depending on the starting point and destination, and to cancel the group traveling, thereby improving the traveling operation rate. be able to.

[Brief explanation of drawings]

Fig. 1 is a plan perspective view showing the configuration of an automatic guided vehicle according to an embodiment of the present invention, Fig. 2 is a side view of the automated guided vehicle, and Fig. 3 shows the received signal of the ultrasonic sensor of the guided vehicle. 4 is a schematic plan view showing a predetermined travel route in the same embodiment, and FIG. 5 (a) (t)) is a flowchart showing the control procedure when forming a group in the management CPU)
and a flowchart (b) showing the control procedure when forming a group in each automatic guided vehicle.
2 is a flowchart showing a travel control procedure on the first and second common travel routes in FIG. 17... Ultrasonic sensor, 19... Control device, 23... Management CPU.

Claims (2)

[Claims] (1) An object-to-object distance detection means that detects the distance between objects and outputs a distance signal, a traveling speed control means that controls the traveling speed according to the distance signal, and a distance between the preceding vehicle and the preceding vehicle. An automatic guided vehicle characterized by comprising a switching means for switching between a following vehicle mode that reduces the distance and a leading vehicle mode that increases the inter-vehicle distance to the preceding vehicle. (2) Divide the entire driving route and set driving sections, set the mode for each driving section, and form a driving group by reducing the distance between the vehicles in front and the following vehicle mode for cooperative driving. 2. The driving control method for an automatic guided vehicle according to claim 1, wherein the driving group is canceled and normal driving is performed by increasing the inter-vehicle distance to the preceding vehicle in a leading vehicle mode.