JPS62288909A - Distance measuring instrument for unattended carriage - Google Patents

Abstract

PURPOSE:To accurately measure a covered distance by operating the distance per pulse in accordance with the number of pulses of a pulse encoder integrated for a prescribed distance and storing this operated distance and calculating the covered distance based on the number of measured pulses in accordance with the distance per one pulse. CONSTITUTION:When a distance measuring instrument for an unattended carriage 1 which is advanced just above a guide line 14 along a traveling course in the direction of an arrow detects a reset position magnet 15a as a reset position mark by a magnet sensor 12', outputs of pulse encoders 11 and 11' attached to covered distance measuring wheels 10 and 11' are read into a microprocessor with the magnet 15a as the start point to start integration. When a distance confirmation position magnet 15b as a distance confirmation position mark is detected by the sensor 12', integration is stopped. The distance per one pulse is operated based on the number of integrated pulses and is stored. Hereafter, the covered distance of the moving carriage 1 is accurately measured based on the latest stored distance per one pulse.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a distance measuring device for an automatic guided vehicle that moves along a travel route, and particularly to a distance measuring device that is used for a long period of time. The present invention relates to an automatic guided vehicle distance measurement device that always accurately measures travel distance by correcting errors.

Automated guided vehicle (hereinafter referred to as AGV)
A guided vehicle (also referred to as a guided vehicle) is an unmanned, self-propelled transportation means that does not have a track such as a rail in its travel route, and it meets the recent demands for labor saving and unmanned production in manufacturing plants. For example, a workpiece may be placed on an automated guided vehicle and transported to a predetermined location within a factory.
In addition, an industrial robot is integrally attached to an unmanned guided vehicle,
It is used as a mobile industrial robot that moves between workstations in a factory and performs predetermined tasks.

[Conventional technology]

Conventionally, a distance measuring device for an AGV moving along a travel route calculates the travel distance by using the AGV's microprocessor to calculate the output of a pulse encoder attached to the AGV's drive wheels or dedicated travel distance measuring wheels. It is done like this. That is, the distance traveled by the AGV is calculated by multiplying the distance per pulse from the pulse encoder, which is stored in advance in the microprocessor of the AGV, by the measured number of pulses from the pulse encoder.

[Problem that the invention seeks to solve]

As mentioned above, the conventional AGV distance measuring device
The AGV's microprocessor calculates the output of a pulse encoder attached to the drive wheel of the GV or a dedicated travel distance measurement wheel, that is, the distance measured from the pulse encoder is calculated by the pre-stored distance per pulse. The travel distance of the AGV is calculated by multiplying the number of pulses.

However, in conventional AGV distance measuring devices, a pulse encoder for measuring distance is attached to the AGV's driving wheels or wheels for measuring travel distance, and the distance traveled is calculated from the output of the pulse encoder. After long-term use, the driving wheels and travel distance measuring wheels to which the pulse encoder is attached may wear down, and the relationship between one pulse of the pulse encoder and the distance corresponding to that one pulse may change, and the distance per pulse may change. , it is not possible to accurately measure the traveling distance of the AGV.

In view of the above-mentioned conventional distance measuring device for an automatic guided vehicle, the present invention has been developed based on the fixed distance from the reset position mark to the distance confirmation position mark and the number of pulse encoder pulses accumulated during the fixed distance. By calculating and storing the distance of To accurately measure the traveling distance of an automatic guided vehicle even if the distance measuring wheels are worn out.

[Means for solving problems]

FIG. 1 is a block diagram showing the configuration of a travel control device for an automatic guided vehicle according to the present invention.

According to the present invention, there is provided a distance measuring device for an automatic guided vehicle that calculates the traveling distance of an automatic guided vehicle moving along a traveling route from the number of pulses from a pulse encoder and the distance per pulse, a reset position detecting means 21 for detecting a reset position mark installed in the reset position mark; and a pulse encoder integrating means for integrating the output of the pulse encoder when the reset position mark is detected, and pulse encoder output from the reset position mark. a pulse encoder integration start means 22 for starting the integration of the distance confirmation position; a distance confirmation position detection means 23 for detecting a distance confirmation position marker installed on the travel route and separated from the reset position marker by a certain distance; a pulse encoder integration termination means 24 that terminates the integration of the pulse encoder output when a mark is detected; It comprises a 1-pulse distance calculation means 25 for calculating the distance per 1 pulse from the number of pulses, and a 1-pulse distance storage means 26 for storing the calculated distance per 1 pulse, Provided is a distance measuring device for an automatic guided vehicle, which calculates a traveling distance from the number of pulses from a pulse encoder measured with reference to the distance.

[For production]

According to the distance measuring device for an automatic guided vehicle of the present invention having the above-described configuration, when the automatic guided vehicle moving along the travel route detects the reset position mark by the reset position detection means 21, the pulse encoder integrates the automatic guided vehicle. The pulse encoder integrating means for integrating the output of the pulse encoder is reset by the starting means 22, and the integrating means of the pulse encoder is started using the reset position mark as a starting point. Further, when the distance confirmation position detecting means 23 detects a distance confirmation position mark separated by a certain distance from the reset position mark, the pulse encoder integration termination means 24 detects the pulses that are accumulated starting from the reset position mark. The encoder integration means completes its integration, and the l pulse distance calculation means 25 calculates a certain distance from the reset position mark to the distance confirmation position mark and the number of pulses counted by the pulse encoder integration means integrated during the certain distance. The distance per pulse is calculated. And 1 pulse distance record 1. #Means 26
The calculated distance per pulse is stored, and from now on, the travel distance of the automatic guided vehicle is calculated from the number of pulses of the pulse encoder measured based on the stored distance per pulse. . This makes it possible to accurately measure the travel distance of the automatic guided vehicle even if the drive wheels and travel distance measuring wheels to which the pulse encoder is attached are worn out after long-term use.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a travel control device for an automatic guided vehicle according to the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram partially schematically showing an automatic guided vehicle using the travel control device of the present invention.

AGVl connects to the road surface 13 through a pair of left and right drive wheels 8.8"
It moves along a predetermined route. A guide wire 14 is buried directly below the travel route, and the AGV 1 travels while being guided by a magnetic field (concentric dotted lines in FIG. 2) generated from the guide wire 14. Then, the magnetic field generated from the induction wire 14 is detected by the pickup coil 4.4°, and the two pink amplifier coils 4
The output balance of 4 degrees makes it possible to detect deviations from the correct running route. That is, the output of the pink amplifier coils 4, 4'' is supplied to the operational amplifier 3, and the output of the operational amplifier is input to the microprocessor 2 as one piece of control information.

The microprocessor 2 inputs the output of the differential amplifier 3 and other information, performs predetermined processing, and controls the acceleration/deceleration control section 5.
, 5''.

The output of the acceleration/deceleration controllers 5 and 5 is sent to the servo amplifier 6.6.
The output of the servo amplifier 6.6' controls the rotation of the servo motors 7, 7'. A pair of left and right drive wheels 8, 8 connected to a servo motor 7.7°
The rotation of the AGV 1 is individually controlled, and the AGV 1 correctly travels directly above the guide line 14 along the travel route.

A pair of moving distance measuring wheels 10.10' are provided outside the left and right driving wheels 8, 8°, and a pulse encoder 11 is provided on this moving distance measuring wheel 10.10'.
, 11' are attached.

The output of the pulse encoder 11.11'' is then supplied to the microprocessor 2, which allows the microprocessor 2 to independently calculate the left and right movement distance of the AGV 1.

Here, the reason why the pulse encoder 11.11' for measuring the travel distance of the AGV 1 is attached to the travel distance measuring wheels 10, 10°, which are separate from the drive wheels 8, 8', is because: This is to prevent the driving wheels 8,8゛ from slipping when the AGV l travels in an arc, such as branching or turning, and causing an error in the travel distance. Needless to say, a pulse encoder may also be installed. In addition, the travel distance measuring wheels 10.10' are not provided as a pair on the left and right, but for example, only one is provided at the lower center of the AGVl, and a pulse encoder is attached to this one travel distance measuring wheel to measure the travel distance of the AGV 1. You may also do so.

A magnetic sensor 12.12' is provided at the lower end of the AGVI outside the travel distance measuring wheel 10.10'. This magnet sensor 12.12' is AGV1
Magnet 1 buried in the road surface 13 which is the driving route of
It is provided at the position corresponding to 5. Here, the magnetic sensor 12. L2° is provided on both the left and right sides of A'G V ], for example,
This is because when the AGV 1 makes a U-turn etc., it switches to the magnet sensor 12 or 12" on the side corresponding to the position of the magneto 15. Of course, the AGV 1 does not make a U-turn etc., and the side corresponding to the magnet 15 If it is specified for deer, the magnetic sensor may be provided only on one side corresponding to the magnet 15.

FIG. 3 is a diagram for explaining how an automatic guided vehicle equipped with the distance measuring device of the present invention performs a correction operation of the distance measuring device.

When the distance measuring device of the AGV i, which is traveling along the travel route in the direction of the arrow in FIG. Pulse encoder 11.1 mounted on the travel distance measuring wheel 10.10°
1' is read into the microprocessor using the reset position magnet 15a as a starting point, and integration is started. Furthermore, without proceeding on the true-F of the guide wire 14, 4Acv
When the distance confirmation position magnet 15b, which is a distance confirmation position indicator, is detected by the magneto-nod sensor 12'', the microprocessor stops reading and integrating the pulses from the pulse encoder.Here, the distance confirmation position magnet 15b is It is accurately separated by a constant distance l from the reset position magnet 15a.The value of this constant distance @It is stored in advance in the magnet sensor 2 of the AGV 1, and the value of this constant distance @It is stored in advance in the magnet sensor 2 of the AGV 1.
The distance per pulse is calculated by the microprocessor Nosa 2 from the fixed distance l from the distance confirmation position magnet.)) 15b and the number of pulses from the pulse encoder 11. be done.

This calculated distance per 1 pulse is stored in the microprocessor 2, and from now on, this distance will be newly recorded in 1. a was done 1
The distance traveled by the AGV1 will be accurately measured on the basis of distance per pulse.

In other words, even if the pulse encoder 11 is used for a long period of time,
, 1 Bi is attached to the moving distance measuring wheel 10.1
Even if 0' is worn out, the distance per pulse at the worn distance measuring wheels 10° and 10° is memorized, and the distance per pulse is used as a reference for the distance measured by the pulse encoder 11 and 11°. Because the distance traveled is calculated from the number of pulses that have been measured, the AGV
It is possible to accurately measure the traveling distance of 1.

FIG. M4 is a flowchart showing an example of a control operation based on the present invention. The branch control operation of the AGVI shown in FIG. 4 will be explained with reference to FIG. 3.

The distance correction process of the distance measuring device starts with step 31 when the AG traveling directly above the guide line 14 along the travel route
Vl proceeds to step 32, where it is determined whether or not the reset position magnet 15a, which is a reset position indicator, has been detected by the magnet sensor 12''.

If it is determined in step 32 that a reset position marker has been detected, the process proceeds to step 33, and if it is determined in step 32 that a reset position marker has not been detected, step 3
1 and continues traveling along the travel route until the reset position marker is detected.

If it is determined in step 32 that the reset position marker has been detected, in step 33 the moving distance measuring wheels 10.10'
The output of the pulse encoder 11.1"1° attached to the is reset, and in step 34, the integration of the output of the pulse encoder 11°11' is started using the reset position magnet 15a (reset position indicator) as the starting point, and, It is determined whether or not the distance confirmation position magnet 15b, which is a distance confirmation position marker, has been detected by the magnet sensor 12° using the steering knob 35. If it is determined in step 35 that the distance confirmation position marker has been detected, step 36
In addition, if it is determined in step 35 that the distance 1iiiIIIffI recognition position mark has not been detected, the step knob 34
The integration of the outputs of the pulse encoders 11 and 11° continues until the distance confirmation position marker is detected.

If it is determined in step 35 that the distance confirmation position marker has been detected, the process proceeds to step 36 and the pulse encoder 11.1 is detected.
1' is completed, and the process proceeds to step 37, where the constant distance l from the reset position magnet 15a ('J upper set position marker) to the distance confirmation position magnet 15b (distance confirmation position marker) and the constant distance are calculated. The distance per pulse is calculated from the number of pulses from the pulse encoder 11, 11' integrated between. Furthermore, in step 38, the calculated distance per pulse is newly set to A.
It will be stored in the microprocessor 2 of the GV 1.

When the distance per pulse is stored in the microprocessor 2 in this way, the distance traveled by the AGVI can be accurately measured based on the newly stored distance per pulse.

For example, if the pulse encoder is used for a long period of time,
Even if the moving distance measuring wheel 11.11'' to which the moving distance measuring wheel 11.11'' is attached is worn out, the distance per pulse on the worn moving distance measuring wheel 10.10'' is stored in the microprocessor 2, Since the travel distance is calculated from the number of pulses measured using this distance per pulse as a reference, the travel distance of the AGV I can always be accurately measured.

In the above embodiment, magnets 15a and 15b are used as reset position markers and distance confirmation position markers.
In addition, although magnetic sensors 12° and 12° were used as sensors for the reset position and distance # confirmation position, such marks and sensors are not limited to magnetic means; for example, the reset position mark can be detected by optical means. It goes without saying that a distance confirmation position indicator and a sensor can also be constructed.

〔Effect of the invention〕

As described above in detail, the distance measuring device for an automatic guided vehicle according to the present invention is based on the fixed distance between the reset position mark and the distance confirmation position mark and the number of pulses from the pulse encoder accumulated over the fixed distance. By calculating and storing the distance per pulse, and calculating the travel distance from the number of pulses of the pulse encoder using this distance per pulse as a reference, even if the drive wheel or moving wheel to which the pulse encoder is attached is used for a long period of time, Even if the distance measuring wheels are worn out, the distance traveled can be accurately measured.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a travel control device for an automatic guided vehicle according to the present invention, FIG. 2 is a block diagram partially schematically showing an automatic guided vehicle using the travel control device of the present invention, and FIG. FIG. 4 is a diagram for explaining how an automatic guided vehicle equipped with the distance measuring device of the present invention performs a correction operation of the distance measuring device, and FIG. 4 is a flowchart showing an example of the control operation based on the present invention. DESCRIPTION OF SYMBOLS 1...Automated guided vehicle, 2...Microprocessor, 4.4゛...Pickup coil, 8.8°...Drive wheel, 10.10'...Wheel for measuring travel distance, 11. 11
'...Pulse encoder, 12.12'...Magnet sensor, 14...Guiding wire, 15,. 15°...Magnet, 15'a...Reset position indicator, 15b...Distance confirmation position indicator, 21...Reset position detection means, 22...Pulse encoder integration start means, 23...
Distance confirmation position detection means, 24...Pulse encoder integration termination means, 25...
1-pulse distance calculation means, 26...1-pulse distance storage means. (1 day)

Claims (1)

[Scope of Claims] A distance measuring device for an automatic guided vehicle that calculates the traveling distance of an automatic guided vehicle moving along a traveling route from the number of pulses from a pulse encoder and the distance per pulse, comprising the steps of: a reset position detection means for detecting a reset position mark installed in the reset position mark; and a pulse encoder integration means for integrating the output of the pulse encoder when the reset position mark is detected, and the pulse encoder output is calculated from the reset position mark by resetting the pulse encoder integrating means for integrating the output of the pulse encoder. pulse encoder integration starting means for starting integration; distance confirmation position detection means for detecting a distance confirmation position marker installed on the travel route and separated by a certain distance from the reset position marker; and detecting the distance confirmation position marker. a pulse encoder integration termination means for terminating the integration of the pulse encoder output when the pulse encoder output is integrated; 1-pulse distance calculation means for calculating a distance per pulse; and 1-pulse distance storage means for storing the calculated distance per 1-pulse; A distance measuring device for an automatic guided vehicle, characterized in that the traveling distance is calculated from the number of pulses from a pulse encoder.