JPS6249524A - Unmanned carrier - Google Patents

Abstract

PURPOSE:To discriminate quickly the deviated drive of an unmanned carrier even in case a guide line is cut at some area within a driving route of the carrier, by deciding that the carrier gets out of the driving route when the intensity of a detected magnetic field is less than a prescribed level over a set period of time. CONSTITUTION:When an unmanned carrier 1 reaches an area where a guide cable 2 is cut within the driving route of the carrier and crosses the cable 2, the intensity of a magnetic field received from a derailment detecting coil 18 is extremely reduced. Then the output of the coil 18 is less than a prescribed level and a line OFF monitor part 19 which receives the output of the coil 18 starts its built-in timer. The time of this timer is set in response to the length of the area where the cable 2 is cut. While the part 19 outputs the deviated drive deciding signal when the set timer time passed. Thus it is discriminated that the carrier 1 gets out of its driving route in case the output of the coil 18 is lower than a prescribed level over a set period of the timer.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an automatic guided vehicle (hereinafter referred to as AGV) which is configured to determine whether the vehicle deviates from a travel route.

Conventional technology In an unmanned factory equipped with a group of CNC equipment such as processing cells and assembly cells, workpieces are transported and delivered, and other operations are carried out between the CNC equipment group and the processing surface or an automated warehouse that stores the processed workpieces. The working sound should be done automatically. Therefore, in recent years, AGVs have been developed that can perform tasks such as transporting and transferring workpieces between CNC facilities and between CNC machines and self-service machines according to control programs. Then, in order to control the running of the AGV, a low-frequency current is passed through a guide wire laid on the running route to generate a magnetic field around the guide wire, and the magnetic field is detected by electromagnetic pickup coils installed on both sides of the AGV. AG depending on the difference in induced voltage in both coils.
It is known to drive and control both driving wheels of a V to cause the AGV to travel along a guide line. On the other hand, there may be cases where it is necessary to lay various tracks within an unmanned factory, and these tracks are made of steel, etc., and in contrast to the above-mentioned electric m guidance control system,
To avoid disturbance, guide lines are removed at locations where they intersect with the orbit.

However, in the case of a conventional AGV, if the output of each pickup coil, and even the difference between the two outputs, becomes zero while traveling in a part of the travel route where the guide wire is removed and does not form a magnetic field, the result is that the actual travel route of the AGV becomes zero. Regardless, A
It is determined that the GV is traveling along a predetermined travel route.

Therefore, if the 80V deviates from the predetermined route while traversing the route portion from which the guide wire has been removed, there will be a delay in the control operation performed after traversing, and the degree of deviation will become extremely large. In this way, power supply in a factory with a layout that includes a guide wire removal section within a predetermined route! ! There were difficulties in unmanned operation using the guidance method.

Problems to be Solved by the Invention An object of the present invention is to provide an automatic guided vehicle that can quickly determine whether the vehicle has deviated from a predetermined travel route even if there is a guide line removal section within the route.

Means for Solving the Problems The present invention detects the magnetic field generated by a guide wire arranged on a travel route, and in an automated guided vehicle set to travel along the guide wire, an unmanned guided vehicle from the guide wire is detected. A detection means for detecting deviation of the guided vehicle, a timer activated by a deviation signal from the detection means and reset when the gilt deviation signal disappears, and a timer for determining deviation of the automated guided vehicle based on the time-up of the timer. did.

Operation The AGV detects the magnetic field generated by the guide wire and travels along the guide wire. The AGV discrimination device determines that the AGV has deviated from the predetermined travel route when the strength of the detected magnetic field falls below a predetermined level for a set time. When the AGV approaches a guide line removal section within a predetermined route, deviation monitoring is started, and if the AGV deviates while crossing the section, deviation is determined immediately after the crossing.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an AGV according to an embodiment of the present invention;
The basic configuration of 1 is conventionally known. Reference numeral 2 denotes an induction cable buried along a predetermined running route of the AGVl. A low-frequency current supplied from a power source (not shown) flows through the induction cable 2, and an induced magnetic field 3 (shown by a broken line) is generated around it. ing. 11.11' are electromagnetic pickup coils arranged symmetrically about the center line of AGVl, each coil 1
1° 11' outputs an induced current corresponding to the strength of the detected magnetic field to a differential amplifier 12, and the differential amplifier 12 amplifies the difference between the outputs of both pickup coils 11 and 11'. The steering calculation unit 13 inputs the output of the differential amplifier 12 and A/D converts it, while also inputting the high-speed V1. A command signal for selectively setting the AGV traveling speed of medium speed V2 or low speed V3 is input, and a speed command signal for both driving wheels 17, 17' for causing the AGVl to travel at the set traveling speed along a predetermined route. is provided to output to the servo circuit 15.15' via the acceleration/deceleration command section 14.14'. The above-mentioned steering calculation section 13. Acceleration/deceleration command section 14.14'
A line OFF monitor unit 19, which will be described later, is mainly composed of, for example, a microprocessor. The drive wheels 17.17' on both sides of 80V1 are connected to the servo circuit 15.1.
5' is provided to be driven and controlled by a servo motor 16, 16' connected to the servo motor 16, 16', but since the above configuration is conventionally known, a more detailed explanation will be omitted.

Next, 18 is a derailment detection coil arranged on the center line of the AGVl, which responds to the strength of the magnetic field 3 crossing the coil 18,
It cooperates with the line OFF monitor section 19 at the subsequent stage to constitute a deviation traveling determination device. That is, the derailment detection coil 18
When the AGVl maintains a predetermined positional relationship with respect to the induction cable 2, that is, when traveling along a predetermined route, it receives a strong magnetic field 3 and outputs a detection output of a predetermined level or higher; When the probe deviates from the magnetic field 3 or crosses the part where the induction cable 2 is removed, it is configured to receive a weak magnetic field 3 or escape outside the magnetic field 3 and output a detection output below a predetermined level or at a zero level.

The line OFF monitor unit 19 A/D converts the output of the derailment detection coil 18, starts a built-in soft timer when it receives a detection output of less than a predetermined level from the coil 1B, and determines whether the derailment is running when the set timer period has elapsed. While outputting an output, the soft timer is also reset when receiving an output of the detection coil 18 of a predetermined level or higher. Further, the one monitor section inputs the set traveling speed command signal and sets the timer time according to the set traveling speed of the AGVI and also the length of the removed portion of the guide cable 2 within the predetermined traveling route. ing.

Hereinafter, the operation of AGvl of this embodiment configured as described above will be explained with reference to FIGS. 1 and 2.

As is conventionally known, when the magnetic field 3 generated by the induction cable 2 is detected by the pickup coil 11.11', the differential amplifier 12. Steering calculation unit 13. Acceleration/deceleration command section 14.14
' and servo circuits 15° and 15' operate in sequence, and AGVl
The rotational direction and speed of each drive wheel 17, 17' is controlled via servo motors 16 and 16' so that the vehicle travels along a predetermined travel route at a set travel speed.

While the AGVl is running, the line OFF monitor unit 19 executes the deviation running determination program shown in FIG. 2 at predetermined intervals. First, the monitor section 19 determines whether derailment or derailment is detected based on the output level of the derailment detection coil 18 at a constant cycle (step $1). That is, when the AGVl is running normally along the induction cable 2, the monitor section 19 receives a high level output from the coil 18 in a strong magnetic field and determines that there is no derailment detected, and moves to step S2, where the built-in The count number G of the soft timer is reset to "0" and the program execution ends.

On the other hand, when the AGVl travels along a predetermined route, reaches the part of the route from which the induction cable 2 has been removed, and starts crossing that part, the strength of the magnetic field received by the derailment detection coil 1 suddenly decreases. The output of the coil 18 is below a predetermined level. Therefore, one monitor unit determines that a derailment has been detected in step S1, and sets the count number Ce to continue monitoring the derailment.
G+1 (Derailment detection direct is "1") and step S3
), then the current speed V changes to high speed V1. based on the set travel speed command signal. It is determined whether the speed is medium speed V2 or low speed V3 (step S4), and the count number C is changed to a set value corresponding to the current speed V by 1. It is determined whether the set value has reached 2 or 3 (step S5, S6 or S7), and if the set value has not been reached, the execution of the program is ended. Note that while AG 1 crosses the part where the induction cable is removed, the coil 18 separates from the magnetic field 3 and its output remains at a low level, so the count number C is set to "1" at step $3 every time this program is executed. It will be updated one by one.

When the AGVl runs normally, immediately after crossing the cable removal section, the derailment detection coil 18 enters the strong magnetic field 3 again and outputs a high level output, and in step S1, it is determined that no derailment is detected, and in step S2, the derailment detection coil 18 is counted. C, the timer is reset, and as a result, it is determined that the AGV 1 has not deviated from the predetermined route, that is, the program is terminated and the normal traveling control described above continues as it is.

The reason for this is, as mentioned above, that the timer time (the product of the set value of 1°K2.3 and the program execution cycle) is set in accordance with the set travel speed and, in turn, the length of the cable removal section. , more specifically, the setting value is 1. 2. 3 sets the cable removal length to the current speed V1. It is set to a value slightly larger than the value divided by the product of V2 or ■3 and the program execution period. If it comes directly above, the count number C is set flK1°K
It is set to a value that does not reach 2 or 3.

On the other hand, while AGVl was crossing the cable removal section, cable 2
If the derailment detection coil 18 is not within the strong magnetic field 3 and the output becomes a low level, it is determined that derailment has been detected every time step S1 is executed immediately after the derailment. The count number C immediately changes to the set value K1. reach 2 or 3. In this case, AGVl
It is determined that the line has deviated from the predetermined route, that is, the process moves to step S8, and a line OFF process is executed, for example, an alarm operation or an operation of stopping the operation of the AGVl is performed.

In the above explanation, the timer time is set according to the length of the cable removal section, and immediately after crossing the relevant part, it is determined whether the AGVl deviates from the predetermined route, and the line OFF process is performed when the deviation occurs. According to this example or a modified example in which the timer is set to another time, AGVI may
derailment detection coil 18 and line OF
Needless to say, the F monitor unit 19 detects the deviation and enables line-off processing.

Effects of the Invention As described above, according to the present invention, it is determined that the AGV has deviated from the predetermined travel route when the strength of the detected magnetic field falls below a predetermined level for a set time corresponding to the travel speed of the AGV. This makes it possible to quickly and reliably detect deviation of the AGV, and to take necessary emergency measures in the event of deviation. Then, when the AGV reaches a guide wire removal section within the predetermined route, it starts monitoring the deviation and can determine whether there is a deviation immediately after crossing the section, and therefore, guide wires cannot be buried in a part of the predetermined route. Even in factories with different layouts, AGVs can be operated and controlled safely using electromagnetic induction.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing an automatic guided vehicle according to an embodiment of the present invention, and FIG. 2 is a flowchart of a control program executed by the line-off monitor section of FIG. 1. 1...Automated guided vehicle, 2...Guidance cable, 3...
Magnetic field, 18... Derailment detection coil, 19... Line O
FF monitor section. (1 other person) Figure 1

Claims (2)

[Claims] (1) Detection means for detecting the magnetic field generated by a guide wire arranged on a travel route and detecting deviation of the automated guided vehicle from the guide wire in an automated guided vehicle set to travel along the guide wire. a timer that is activated by a departure signal from the detection means and reset when the departure signal disappears; and an automatic guided vehicle that determines whether the automatic guided vehicle has departed from the automatic guided vehicle based on a time-up of the timer. (2) The automatic guided vehicle according to claim 1, wherein the timer is set to measure time according to the traveling speed of the automatic guided vehicle.