JPH0459643B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a self-propelled automatic guided vehicle that is introduced in a factory or the like for the purpose of transporting articles.

<Prior art> Conventionally, as disclosed in, for example, Japanese Patent Application Laid-Open No. 51-61970, in an automatic guided vehicle (hereinafter simply referred to as an unmanned vehicle), the rotation axes of two drive wheels are aligned with the longitudinal center of the vehicle. There is a technology that allows unmanned vehicles to travel sideways by arranging them on a virtual plane parallel to a line.

The above-mentioned unmanned vehicle has the advantage that the load can be carried in or transferred to the unloading station easily and over the shortest distance.

<Problems to be Solved by the Invention> Fig. 4 is a schematic plan view for explaining the problems with the above-mentioned unmanned vehicle. The unmanned vehicle G was placed beside the station S without any correction of its inclination. Therefore, the load could not be transferred smoothly between the station S and the unmanned vehicle G, and the loaded load was unstable on the unmanned vehicle G.

<Means for Solving the Problems> The present invention includes at least two drive wheels, a means for rotationally driving each of the drive wheels, a means for rotating each of the drive wheels about a rotation axis, and at least one a means for detecting a turning angle of the driving wheel; and a stop detector for controlling the means for rotationally driving the driving wheel according to the detected turning angle of the driving wheel, and detecting a detection target provided at a stopping position. is provided corresponding to each drive wheel, and when the stop detector detects the detected tool, the rotation of the drive wheel corresponding to the stop detector is independently stopped.

<Operation> By detecting the turning angle of at least one drive wheel, the inclination of the unmanned vehicle is detected, and the means for rotationally driving the drive wheel is controlled based on the detection result to correct the inclination. In addition, even if the tilt is not completely corrected and the unmanned vehicle approaches the stop position (for example, a loading/unloading station) in an inclined state, the detector on the side approaching the stop position will first When the detected device is detected, the corresponding drive wheel stops rotating, and the other drive wheels continue to rotate until the corresponding detector detects the detected device, and then reach the stop position with the tilt completely corrected. Stop.

<Example> Figure 1 shows the vicinity of a loading (or unloading) station 2 where an unmanned vehicle 1 is placed next to it, and the unmanned vehicle 1
FIG.

This unmanned vehicle 1 is formed to be long in the vertical direction 3, and swing wheels 6, 7 of two drive wheels 4, 5 are arranged on a virtual plane parallel to the vertical direction 3. The driving wheels 4 and 5 are
Steering control devices 8 and 9, which will be described later, enable the vehicle to turn around pivot axes 6 and 7, respectively. Reference numerals 10 and 11 each indicate a pair of caster-shaped driven wheels, which are rotatable.

The above-mentioned steering control devices 8 and 9 will be explained.
The drive wheels 4 and 5 are directly connected to drive motors 12 and 13, and are rotationally driven by the motors, respectively. Drive wheels 4, 5 and drive motors 12, 13 are provided on pulleys 14, 15. Reference numerals 16 and 17 indicate swing motors, and 18 and 19 indicate small pulleys rotated by the motors.
Belts 20 and 21 are wound around 4 and 15, respectively. Induction antennas 22 and 23 are provided on the driving wheels 4 and 5, and each antenna is located in front of the corresponding driving wheel 4 and 5 in the traveling direction. The induction antennas 22, 23 each include two induction coils 22a, 22a and 23a, 23a.
and is coupled to a corresponding drive wheel so as to be able to swing together with the corresponding drive wheel over any desired control angle. Reference numeral 24 indicates a guide wire buried in the floor surface, and by energizing the guide wire 24, the position of the guide wire is detected by an antenna.
The small pulley 18 is provided with a pulse detector 25 that detects the number of rotations of the pulley 18. The driving wheel 4 is located parallel to the longitudinal direction 3 of the unmanned vehicle 1, that is, the driving wheel is located at a position 4a shown by the two-dot chain line in FIG. Based on the state in which the lines 1 coincide with each other, the pulse detector 25 detects the rotation speed of the small pulley 18 or the rotation speed of the swing motor 16, thereby detecting the angle θ at which the drive wheel 4 is turning. There is.

Reference numerals 26 and 27 indicate stop detectors provided on the bottom surface of the unmanned vehicle 1, and in this embodiment, known proximity switches (magnetic switches) for detecting metal bodies are applied to the detectors 26 and 27. The detector 2 is installed on the floor where the unmanned vehicle 1 near the station 2 stops.
Detection targets 28 and 29 made of metal bodies (for example, metal sheets, etc.) are placed at positions corresponding to 6 and 27, respectively. One of the detectors 26 is the device to be detected 28
When detected, the rotational drive of the drive wheel 4 is stopped, and when the detector 26 passes the detected tool 28 after coasting, a mechanical brake is forcibly applied to the drive wheel. Similarly, the detector 27, the detected device 28, and the drive wheel 5 operate.

Next, the travel control section of the unmanned vehicle will be explained based on FIG. In this block diagram, numeral 30 indicates a control section, which is internally equipped with a CPU and various storage devices. 31 and 32 are respectively the swing motors 1
6 and 17 are shown, and 33 and 34 are drive parts of travel motors 12 and 13, respectively, and each drive part directly controls the rotation speed of each motor.

When driving in a normal straight line, the induction antennas 22, 2
According to the detection result of the guide line by No. 3, the drive units 31 and 32 of the swing motors 6 and 7 are controlled, and the unmanned vehicle moves while correcting its position. Also, when stopped, the control unit 3
0 to the drive unit 33 of the travel motors 12, 13,
A running stop command is sent to 34.

A case in which the unmanned vehicle 1 approaches the station 2 from a direction 35 perpendicular to the station 2 (hereinafter referred to as "traversing") as shown in FIG. 1 will be described next. FIG. 3 shows a flowchart of the running state of the unmanned vehicle 1. At the same time as the unmanned vehicle 1 starts running (step), the turning angle of the drive wheels 4 is always detected by the pulse detector 25 ( step). If the angle exceeds a certain value, for example, if the absolute value exceeds 70 degrees, including a negative value (step), the unmanned vehicle 1 recognizes that it is moving in a rampant manner (step), and follows the steps below. . Also,
If the absolute value of the above angle is less than 70 degrees, the vehicle will not recognize that the vehicle is moving sideways, but will continue to drive, determining that the steering is simply to correct the travel trajectory. If it is determined that the vehicle is traveling sideways, it is determined whether the above angle θ is 90 degrees (step), and if it is 90 degrees, YES is selected.
Since the unmanned vehicle has no inclination, the vehicle continues traveling without any correction being made to the vehicle (step). If the angle θ is not 90 degrees, the process proceeds to NO and the tilt of the unmanned vehicle 1 is corrected as follows. That is, it is determined whether the angle θ is smaller than 90 degrees (step), and if it is smaller, the drive wheel 4 to which the pulse detector 25 is attached (hereinafter referred to as the first drive wheel) 4 is the other drive wheel (hereinafter referred to as the first drive wheel). Since the second driving wheel 5 is closer to the station 2 than the second driving wheel 5 (as shown in FIG. 4), the traveling speed V2 of the second driving wheel 5 is set higher than the traveling speed V1 of the first driving wheel 4 (step). The above-mentioned inclination of the unmanned vehicle 1 is corrected.
Conversely, if the angle θ is larger than 90 degrees, the second driving wheel 5 is closer to the station 2 than the first driving wheel 4, so the traveling speed V1 of the first driving wheel 4 is The running speed of the driving wheels 5 is made higher than V2 (step), and the above-mentioned inclination of the unmanned vehicle is corrected.

As described above, after making the correction (step) or continuing to drive (step), the detectors 26 and 27 on the unmanned vehicle 1 detect the detection object 28 on the floor,
29 is detected, each drive wheel 4, 5
Stops driving. Although the rotational speed of the drive wheels 4 and 5 decreases extremely, they do not come to a complete stop, but rotate due to inertia and gradually approach the station 2. Next, when the detectors 26 and 27 no longer detect the detected tools 28 and 29, the drive wheels 4 and 5 are forcibly stopped. While the detectors 26 and 27 are detecting the detected tools 28 and 29, the inclination of the unmanned vehicle 1 that has not been corrected due to the speed difference between the two drive wheels is corrected. That is, while the drive wheel that detected the detection target first is rotating by inertia, the other drive wheels are running at a steady speed, so the entire unmanned vehicle 1 gradually becomes parallel to the station 2. While the inclination is being corrected in the desired direction, the unmanned vehicle approaches station 2 and becomes completely parallel to station 2 when it actively stops.

<Effects of the Invention> As explained above, according to the present invention, an unmanned vehicle can be stopped at a stop position (for example, a loading/unloading station) without tilting, and the unmanned vehicle can be stopped at a stop position (for example, at a loading/unloading station) without tilting. It is possible to smoothly transfer cargo, etc. Furthermore, as a result, the loaded state of the load is stabilized, so that it is possible to prevent the load from collapsing while the unmanned vehicle is running.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, and is a schematic plan view showing the vicinity of a load transfer station next to which an unmanned vehicle is placed and the unmanned vehicle. FIG. 1 a is an enlarged plan view of the drive wheels shown in the first diagram. 2 is a block diagram showing the running control section of the unmanned vehicle shown in FIG. 1, FIG. 3 is a flowchart showing the running state of the unmanned vehicle, and FIG. 4 is a schematic diagram for explaining the problems of the conventional device. FIG. 4, 5... Drive wheel, 6, 7... Swivel axis, 12,
13... Drive motor, 16, 17... Swivel motor, 25... Pulse detector.

Claims (1)

[Scope of Claims] 1. At least two drive wheels, means for rotating each of the drive wheels, and means for rotating each of the drive wheels around a turning wheel, at least one
means for detecting the turning angle of the two drive wheels;
A means for rotationally driving the drive wheels is controlled based on the detected turning angle of the drive wheels, and a stop detector is provided corresponding to each drive wheel to detect a detected tool provided at a stop position. 1. An automatic guided vehicle characterized in that rotation of a drive wheel corresponding to a stop detector is independently stopped when a detector detects a detected tool.