JPH04287101A - Automatic carrier and control method for the carrier - Google Patents

Abstract

PURPOSE:To improve efficiency for carriage by detecting whether an object to be an obstacle exists in the advancing direction of the own carrier or not and detecting the moving direction and moving speed of the object to be the obstacle. CONSTITUTION:Based on a detection signal from a sensor directed to the front advancing direction of the own carrier, an obstacle detection processing 8 decides whether the object exists in the front advancing direction or not. When it is decided in this obstacle detection processing 8 that the obstacle exists in the front advancing direction, a speed and distance detection processing 9 measures the speed and the distance from the own carrier and a calculation processing 10 calculates a relative space between the own carrier and the object after the lapse of fixed time. Thus, the change amount of a current relative position is calculated from the respective predictive positions of arrival and the speed of the own carrier is controlled so as to be accelerated in an acceleration processing 12 in the case of enlarging the change amount or to be decelerated in a deceleration processing 13 in the case of reducing it.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transport vehicle used for transporting objects within a factory and a method of controlling the transport vehicle.

0002

[Prior Art] A conventional guided vehicle has a sensor that detects whether there is an object in the direction in which the vehicle is traveling, and when it detects that there is an object within a certain distance,
Or, the vehicle was supposed to stop when it felt some kind of impact.

0003

[Problems to be Solved by the Invention] As described above, in the conventional technology, when it is detected that there is an object within a certain distance in the direction of travel, the vehicle is stopped, and the collision In order to prevent damage to the transport vehicle itself or the loaded items due to impact, the speed cannot be increased too much, especially in transportation systems where the transport vehicle moves on the same floor as people, due to safety considerations. 4km/h slower than the speed
Generally, it was only a matter of time, and the efficiency was extremely low. Furthermore, when using a plurality of conveyance vehicles, there is a drawback that the interval between them cannot be made very short.

[0004] An object of the present invention is to provide an automatic guided vehicle and a control method thereof that solve the above problems.

[0005]

[Means for Solving the Problems] In order to achieve the above-mentioned object, an automatic guided vehicle according to the present invention is an automatic guided vehicle that automatically transports objects in a factory, and is designed to avoid obstacles in the direction of travel of the vehicle. It has means for detecting whether or not an object is present, and means for detecting the moving direction and speed of the object as an obstacle.

[0006]Furthermore, in the method for controlling an automatic guided vehicle according to the present invention, there is provided a method for controlling an automatic guided vehicle that automatically transports objects in a factory, and in which an object that becomes an obstacle in the direction of movement of the self-vehicle is detected. It has means for detecting whether or not the object exists, and means for detecting the moving direction and moving speed of the object serving as an obstacle,
A process for determining the relative relationship between the detected position of an object in the direction of travel and the position of the own vehicle, the speed of the detected object,
A process for determining the position that the object will reach after a certain time based on the moving speed, and a means for determining the position that the own vehicle will reach at that time from the moving direction and moving speed of the own vehicle,
The process calculates the amount of change in the current relative position from the position each of them will reach. If the amount of change is increasing, the speed of the own vehicle is accelerated, and if it is decreasing, the speed of the own vehicle is increased. This controls the speed of the vehicle.

[0007]

[Operation] Finds the relative relationship between the position of the detected object as an obstacle in the direction of travel and the position of the own vehicle, and determines the speed of the detected object and the probability that the object will arrive after a certain period of time from the direction of travel. Find the position that the car will reach at that time based on the direction of movement and speed of the car, and calculate the amount of change in the current relative position from each expected position. If the amount of change is increasing, the speed of the own vehicle is accelerated, and if the amount of change is decreasing, the speed is decreased.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, 1 and 2 are automatic guided vehicles that move only in directions regulated by guide rails 3. The automatic guided vehicles 1 and 2 have their traveling directions 4,
Sensors 6a and 6b facing 5 are attached. The sensors 6a and 6b have a function of detecting whether or not there is an object in each direction, and a function of detecting the speed of the automatic guided vehicles 1 and 2. In this case, sensors that utilize light reflection are generally well known as sensors that detect the presence or absence of an object. In addition, sensors that detect speed include those that apply the Doppler effect, and those that measure distance using laser beams and calculate speed from changes in minute intervals of time over that distance.

FIG. 2 is a flowchart for this automatic guided vehicle 1 to maintain a relative distance from another automatic guided vehicle 2. First, in speed capture processing 7, the speed of the own vehicle is captured and stored using the sensor 6a or 6b.

Next, in obstacle detection processing 8, it is determined whether or not there is an object in the forward direction of travel based on the detection signal from the sensor 6a directed in the forward direction of the own vehicle. If it is determined here that there is no object as an obstacle, the process returns to the speed capture process 7, the speed capture is repeated again, and the speed capture process 7 and the obstacle detection process 8 are repeated.

When the obstacle detection process 8 determines that there is an obstacle in the forward direction of travel, the speed and distance detection process 9 measures the speed and the distance from the own vehicle and performs calculation processing. In step 10, the relative distance between the vehicle and the object after a certain period of time is calculated. The calculation at this time is performed as follows.

[0013]L=(V1-V2)×T

[0014] Here, L is the relative distance between the own vehicle and the object, and V1 and V2 are the respective velocities of the own vehicle and the object. For V1 and V2, the forward traveling direction 4 in FIG. 1 is positive,
By setting the traveling direction 5 of the vehicle and the object behind to be negative, the direction can be taken into account. T is a time that should be expected, and is set to a value that is sufficiently small compared to the time required for the transport vehicles 1 and 2 to stop. For example, if the time required for transport vehicles 1 and 2 to stop is 10 seconds, 10%
1 second or less is appropriate.

Next, in distance determination processing 11 shown in FIG. 2, the validity of this distance is determined. That is, L is an appropriate distance L1
If so, the flow returns to the beginning of the flowchart without changing the speed.

If L is smaller than L1, in deceleration processing 13, a speed obtained by subtracting V1 by a certain amount is substituted for V1, and similar calculation processing 10 is performed again. This, L is L1
This is repeated until the speed becomes larger than L1, and the speed V1 when the speed becomes larger than L1 is commanded to the speed control device (not shown) of the transport vehicle, and the process returns to the beginning of the flowchart.

[0017] Furthermore, when L is considerably smaller than L1,
Conversely, in acceleration processing 12, the speed increased by a certain amount is substituted into V1, calculation processing 10 is performed, and when an appropriate L is obtained, the speed of the conveyance vehicle is changed. An appropriate L is not larger than L1, but is about 10% smaller.

[0018] In this way, the speed of the transport vehicle can be increased and the interval can be made sufficiently small.

(Embodiment 2) FIG. 3 is a block diagram showing Embodiment 2 of the present invention. In the figure, 15 is a transport vehicle,
17 is the traveling direction of the transport vehicle 15. 18-1, 18-
Sensors 2, . . . , 18-n are attached to the transport vehicle 15 and measure the distance between the transport vehicle 15 and an object. 1
6 is a certain object, and it is assumed that it is moving in the traveling direction 16a.

A control method in the second embodiment of the present invention will be explained with reference to FIG. First, speed import processing 19
, the speed and direction of movement of the own vehicle are captured.

Next, in obstacle detection processing 20, it is determined whether the sensors 18-1, 18-2, . . . , 18-n have detected an object. If there is no object, return to the first step, and if an object is detected, distance detection processing 2
1. The position is measured in distance detection processing 22 at further minute time intervals. The reason for measuring twice at minute intervals is to calculate the speed from the change in position in the speed calculation process 23. As a result, the position, moving speed, and moving direction of the object 16 are determined.

In the next graph creation process 24, the determined position, moving speed, and moving direction of the object 16 are created into a graph as shown in FIG. In this figure, the origin 0 is the current position of the vehicle, and P is the position of the object 16. In addition, A is a vector representing the moving direction and speed of the own vehicle, and similarly, B is a vector representing the moving direction and speed of the own vehicle.
is a vector indicating the direction and speed of movement. Furthermore, the circle C centered at the tip of the vector B takes into consideration the size of the object and errors in measured values and calculated values, and the circle C centered on the tip of the vector
6 is the possible area to reach.

In determination processing 25 in FIG. 4, it is determined whether the tip of vector A is within circle C or not. If the tip of A is inside circle C, a command to reduce the speed is sent to the vehicle's speed control device in deceleration processing 26, and if the tip of A is not in circle C, the speed is reduced in acceleration processing 27. I will send an order to raise the level. Thereafter, by repeating the speed capture from the initial speed capture process 19, the distance between the object 16 and the own vehicle is always maintained at a safe distance or higher.

[0024]

As explained above, according to the present invention, it is possible to improve the speed of the transport vehicle and also improve the efficiency of transport between the transport vehicles. In particular, the track-type conveyance vehicle as in Example 1 can be operated at high speed while minimizing the distance between the vehicles, so that its efficiency can be significantly improved. In addition, the distance between people walking in the path of the transport vehicle is kept to a minimum, and the distance can be maintained with safety in mind, which prevents accidents such as collisions with people and injuries. It is also useful to do.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a flowchart of the first embodiment.

FIG. 3 is a plan view showing a second embodiment of the present invention.

FIG. 4 is a flowchart of Example 2.

FIG. 5 is a determination vector diagram of Example 2.

[Explanation of symbols]

1, 2 Transport vehicle 3 Guide rails 4, 5 Arrows 6a, 6b indicating the traveling direction of the transport vehicle
Sensor for detecting distance and speed 7 Process for capturing speed 8 Process for detecting the presence or absence of obstacles 9 Process for detecting speed and distance 10 Process for calculating distance 11 Process for determining calculated distance 12 Process for reducing speed 13 Process for increasing speed 19 Process for capturing speed 20 Process for detecting the presence or absence of obstacles 21, 22 Process for detecting distance 23 Process for detecting speed 24 Process for creating a graph 25 Process for determining 26 Process for instructing deceleration 27 Processing to instruct acceleration

Claims (2)

[Claims] Claim 1: An automated guided vehicle that automatically transports objects within a factory, comprising: means for detecting whether or not there is an object that will be an obstacle in the direction of movement of the vehicle; An automatic guided vehicle characterized by having means for detecting a moving direction and a moving speed. [Claim 2] A method for controlling an automatic guided vehicle that automatically transports objects in a factory, comprising means for detecting whether or not there is an object that becomes an obstacle in the direction of movement of the self-vehicle; means for detecting the moving direction and moving speed of an object, a process for determining the relative relationship between the detected position of the object in the traveling direction and the position of the own vehicle, and the speed of the detected object; A process for determining the position that the object will reach after a certain period of time based on the moving speed, a means for determining the position that the own vehicle will reach at that time from the moving direction and speed of the own vehicle, and each destination. The process calculates the amount of change in the current relative position from the expected position, and if the amount of change is increasing, the speed of the own vehicle is accelerated, and if it is decreasing, the speed of the own vehicle is decelerated. 1. A method for controlling an automatic guided vehicle, the method comprising controlling an automatic guided vehicle.