JPH0683448A - Traveling controller of unmanned carriage - Google Patents

Abstract

PURPOSE:To smoothly travel at a corner part and reduce the cost of a guide member by almost equalizing the radii of the corner parts of the guide member and driving a right and a left driving wheels at a speed ratio nearly equal to a travel distance ratio at the time of the corner part travelling. CONSTITUTION:The travel machine body of the unmanned carriage automatically travels along a reflecting tape 13 for guidance based on the detection of a photosensor 12. If the carriage is deviating from the reflecting tape 13, the right and left driving wheels are driven at a specific speed ratio to correct the direction. This speed ratio is nearly equalized to the travel distance ratio of the right and left driving wheels 4 at a corner part which is equalized in turning radius, so the driving wheels 4 are not driven and switched frequently during the corner part travel and the carriage automatically travel along the reflecting tape 13. Therefore, the corner part travel can be made extremely smooth. Further, the kinds of the reflecting tapes 13 for the corners are limited to one, so the cost is reducible and laying operation is facilitated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling control device for an automated guided vehicle used in factories and warehouses.

[0002]

BACKGROUND OF THE INVENTION Generally,
Some of these types of unmanned guided vehicles travel on the basis of independent motor drive of the left and right drive wheels, and this one detects the traveling direction of the machine body with reference to a guiding member laid in advance on the carrying path. At the same time, the direction is corrected based on the drive control of the left and right drive wheels corresponding to the direction detection, and the vehicle automatically travels along the guide member. However, in the past, since the direction correction was performed based on so-called ON-OFF control for stopping one driving wheel, when traveling along a guide member corner portion formed in an arc shape, The drive wheels on the peripheral side are frequently turned on and off, and as a result, the traveling machine frequently swings to the left and right and slips on the drive wheels on the inner peripheral side occur, resulting in smooth running in the corners. The reality is that it cannot be done.
Moreover, since the conventional guide member is formed by using various kinds of corners having different diameters, it may cause a significant cost increase in the production of a wide variety of products in small quantities. It was the actual situation.

[0003]

SUMMARY OF THE INVENTION The present invention was devised with the object of providing a traveling control device for an automatic guided vehicle, which is capable of eliminating these drawbacks in view of the above circumstances. A direction sensor that detects the traveling direction of the machine on the basis of a guide member laid on the transport path on a traveling machine that travels by independently driving the left and right drive wheels with a motor, and detection of the direction sensor In an automated guided vehicle comprising a traveling control unit that causes the traveling body to travel along the guide member based on the drive control of the left and right drive wheels, the corner radius of the guide member is substantially unified, while the traveling control unit has , A straight traveling control mode in which the left and right drive wheels are driven at the same speed and a direction correction mode in which the left and right drive wheels are driven at a predetermined speed ratio are set, and the speed ratio in the direction correction mode is set to the corner It is characterized in that substantially matched to the travel distance ratio of the left and right drive wheels during part traveling.
Further, according to the present invention, the corner traveling can be performed very smoothly, and the cost of the guide member can be reduced and the laying work can be simplified.

[0004]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, one embodiment of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 denotes a traveling machine body of an automated guided vehicle, and a front end bottom portion of the traveling machine body 1 is provided with a pair of left and right driven wheels 2 which can be displaced in a rolling direction following the traveling of the machine body, while a rear end thereof is provided. The bottom portion is provided with a pair of left and right drive wheels 4 that are independently driven by dedicated drive motors 3. That is, the traveling machine body 1 moves straight in the front-rear direction based on the forward and reverse driving of the left and right drive wheels 4, and the traveling direction is changed based on the deceleration or stop of one of the drive wheels 4. . Reference numeral 5 is a battery mounted on both left and right sides of the traveling machine body 1.

Reference numeral 6 denotes an ultrasonic sensor provided at each of a front end portion and a rear end portion of the traveling machine body 1, and one of these ultrasonic sensors 6 is provided at the front end portion when moving forward. On the other hand, although the one disposed at the rear end is used when moving backward, each ultrasonic sensor 6 includes an ultrasonic wave transmitting unit 7 that transmits an ultrasonic wave in the traveling direction of the traveling body 1. The ultrasonic wave reception unit 8 detects an obstacle based on the reception of the reflected ultrasonic wave.

Further, 9 is a forward and backward direction sensor unit, and of these direction sensor units 9, the forward direction sensor unit 9 is to be located forward of the axle position of the drive wheels 4 to the traveling vehicle body 1. On the other hand, the one for the reverse drive is provided at the rear end of the traveling machine body 1 so as to be located rearward of the axle position of the drive wheels 4, while the one for the reverse drive is provided at the rear end of the vehicle. At the lower end of the direction sensor unit 9, a pair of left and right reflective photosensors 12 each including a light emitting unit 10 and a light receiving unit 11 are arranged in parallel at a predetermined interval (40 mm in the embodiment). That is, the left and right optical sensors 12 are the same as those of the traveling vehicle body 1.
Predetermined width (50m in the example) laid on the automatic conveyance route of
m) emits light toward the guiding reflection tape 13 for guiding,
It is provided so as to receive the light reflected by the guiding reflection tape 13, and the traveling body 1 is traveling along the guiding reflection tape 13 in a state where the left and right optical sensors 12 receive the reflected light. On the other hand, when only one of the left and right optical sensors 12 receives the reflected light, it can be determined that the traveling machine body 1 is deviating from the guiding reflective tape 13.

By the way, as the guiding reflection tape 13, straight line portions 13a and corner portions 13b are prepared in advance, and they are laid on the floor surface in an appropriate combination so as to be along the automatic conveying route. The diameter of 13b is unified. In other words, straight line 13a and corner 1
3b, it can be used for any shape of conveyance path. For example, when forming a corner portion having a diameter larger than that of the corner 13b, as shown in FIG. 6, the straight line 13a and the corner 13b are formed. It is designed to respond by combining and.

Furthermore, 14 is a control unit provided in the traveling machine body 1, and the control unit 14 is constituted by using a so-called micro computer (including MPU, ROM, RAM, etc.), The drive motor 3, the ultrasonic sensor 6, and the optical sensor 12 are connected to the input / output terminals of the control unit 14.
Etc. are connected. That is, in the control unit 14, the automatic traveling control for automatically traveling the traveling body 1 along the guiding reflective tape 13 based on the detection of the optical sensor 12, and the traveling stop of the traveling body 1 based on the detection of the ultrasonic sensor 6 A control program such as an obstacle detection control to be performed and a forward / reverse switching control for switching the forward / backward traveling of the traveling body 1 is stored in advance,
Hereinafter, these control procedures will be described based on the flow chart. Incidentally, the forward / reverse switching control uses a general control procedure, and a description thereof will be omitted.

In the automatic traveling control, first, the ON / OFF state of the left and right light sensors 12 is determined. When both the left and right optical sensors 12 are both ON, the left and right drive wheels 4 are driven at full speed so that the traveling vehicle 1 travels straight. On the other hand, when both the left and right optical sensors 12 are both OFF, the traveling vehicle 1 is turned on. When the left and right drive wheels 4 are stopped to stop and either the left or right optical sensor 12 is OFF, the OFF side drive wheels 4 are turned ON while maintaining the full speed drive state in order to correct the direction of the traveling vehicle body 1. The side drive wheels 4 are driven at a half speed, and the speed ratio between the full speed drive and the half speed drive is determined in advance by using the following arithmetic expression. Here, R is the turning radius of the corner portion 13b, A is the trench width of the left and right driving wheels 4, x is the turning radius of the inner driving wheel 4 (RA−A / 2), and y is the turning radius of the outer driving wheel 4. (R
+ A / 2). First, the corner portion 13b
When traveling 1/4 circle along, the distances L1 and L2 traveled by the inner and outer drive wheels 4 are L1 = 2 · π · x · 1/4 = 2 · π · ( R-A / 2) ・ 1/4 L2 = 2 ・ π ・ y ・ 1/4 = 2 ・ π ・ (R + A / 2) ・ 1/4 Here, the drive speed of the outer drive wheel 4 (full speed drive speed) ) V
When 2 is set to “1”, the driving speed (half speed driving speed) V1 of the inner drive wheel 4 is V1 = (RA−A / 2) / (R + A / 2) Therefore, the corner portion 13b is slipped. The speed ratio of the left and right drive wheels 4 that can travel smoothly without doing is V2: V1 = 1: (RA−A / 2) / (R + A / 2), and this speed ratio is used for left / right drive when correcting the direction. The wheel 4 is used as a speed ratio of the wheel 4. For example, when R = 500 mm and A = 350 mm, V2: V1 = 1: (500-350 / 2) / (500 + 350/2) ≈1: 0 It becomes 0.48, and by using this speed ratio, smooth cornering is possible.

On the other hand, in the obstacle detection control, a predetermined ultrasonic signal (transmitting time is set to 1 ms in the embodiment) is output from the ultrasonic transmitting unit 7 at predetermined time intervals (20 ms in the embodiment), and the obstacle is detected. Whether or not the ultrasonic wave reception unit 8 receives the ultrasonic wave signal reflected by (at the time of ultrasonic wave transmission, the reception gate is closed to avoid direct reception) is determined.
If the determination is NO, the ultrasonic wave transmission and the aircraft traveling are continued, while if the determination is YES, the preset stop timer and the travel recovery timer are started and the respective timers are terminated. Although the ultrasonic wave transmission and the aircraft traveling are suspended until the suspension timer changes to a different time for each automated guided vehicle (in the example, the automated guided vehicles A, B, C.
..J = 1s, 2s, 3s ... 10s) is set,
Further, the traveling return timer is set to a time obtained by adding a certain time (1 s in the embodiment) to the rest timer.

That is, as shown in FIG. 12, when the automatic guided vehicle A attempting to rub against the automatic guided vehicle B receives an ultrasonic wave transmitted from the automatic guided vehicle B, the automatic guided vehicle A transmits ultrasonic waves. And the airframe traveling is stopped by the timer time (in the embodiment, 1
However, since the rest timer is updated by receiving the ultrasonic wave continuously transmitted by the automated guided vehicle B again, the dormant timer is maintained until the automated guided vehicle B rubs against each other. Then, after the pause timer and the travel recovery timer have expired, the travel is automatically resumed.

Further, as shown in FIG. 13, when both of the unmanned guided vehicles A and B facing each other simultaneously receive ultrasonic waves,
Both unmanned guided vehicles A and B suspend ultrasonic wave transmission and airframe traveling for a timer time, but the unmanned guided vehicle A having a short rest timer time automatically and automatically resumes traveling after the rest timer time has elapsed. On the other hand, the unmanned guided vehicle B having a long rest timer time updates the rest timer by receiving the ultrasonic waves transmitted from the unmanned guided vehicle A that has returned from traveling, and therefore maintains this state until the unmanned guided vehicle A rubs against each other. Then, after the pause timer and the travel recovery timer have expired, the travel is automatically resumed.

In the embodiment of the present invention configured as described above, the traveling machine body 1 of the automatic guided vehicle automatically travels along the guiding reflection tape 13 based on the detection of the optical sensor 12,
When the vehicle is deviating from the guiding reflective tape 13, the left and right drive wheels 4 are driven at a predetermined speed ratio to correct the direction. Since the traveling distance ratio of the drive wheels 4 is substantially equal to that of the drive wheels 4, the drive wheels 4 are
The vehicle automatically travels along the guiding reflective tape 13 without being frequently switched. Therefore, as in the conventional case where the drive wheels 4 are ON-OFF controlled to correct the direction,
It is possible to reliably prevent the traveling vehicle body 1 from swinging to the left and right frequently and to prevent the inner peripheral side drive wheels 4 from slipping, thereby making it possible to make corner traveling extremely smooth.

Moreover, since the corner portions 13b of the guiding reflection tape 13 are unified into one type, a great cost reduction can be achieved along with the reduction of the types and the laying work can be remarkably simplified. it can.

The present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can be implemented in a circuit that does not include a micro computer, and the dimensions, timer time, etc. shown in the embodiment are appropriate. It goes without saying that it can be changed.

[0016]

In summary, since the present invention is constructed as described above, the traveling direction of the machine body is detected based on the guide member so as to automatically travel along the guide member laid in advance on the conveyance path. In addition, while correcting the direction based on the drive control of the left and right drive wheels corresponding to the direction detection, the radius of the corner portion of the guide member is substantially unified, and the left and right drive wheels are changed when the corner portion is traveling. Since the direction of the traveling aircraft is corrected by driving at a speed ratio that substantially matches the traveling distance ratio,
The drive wheels are not frequently switched, and the vehicle automatically travels along the guide member. Therefore, the drive wheels are turned on.
As in the case where the direction is corrected based on the -OFF control, it is possible to reliably prevent the traveling machine body from frequently swinging to the left or right and the inner drive wheel from slipping.
The corners can be run extremely smoothly.

Moreover, since the guide member can be formed by only two kinds of the corner portion and the straight portion, it is possible to significantly reduce the cost with the decrease of the kind, or the guide member. The work of laying the members can be simplified and the workability can be improved.

[Brief description of drawings]

FIG. 1 is a plan view of an automatic guided vehicle.

FIG. 2 is a side view of the same.

FIG. 3 is a front view of the same.

FIG. 4 is a rear view of the same.

FIG. 5 is a plan view showing a relationship between a direction sensor and a reflective tape.

FIG. 6 is a plan view showing an example of laying a guiding reflective tape.

FIG. 7 is a block diagram showing a schematic configuration of a control mechanism.

FIG. 8 is a flow chart showing a control procedure of travel control.

FIG. 9 is a timing chart showing the operation of traveling control.

FIG. 10 is a flow chart showing a control procedure of obstacle detection control.

FIG. 11 is a timing chart showing the action of obstacle detection control.

FIG. 12 is a timing chart of the same.

FIG. 13 is a timing chart of the same.

[Explanation of symbols]

 1 Traveling Vehicle 2 Driven Wheel 3 Drive Motor 4 Drive Wheel 5 Battery 6 Ultrasonic Sensor 7 Ultrasonic Transmitter 8 Ultrasonic Receiver 9 Directional Sensor Unit 10 Light Emitting Section 11 Light Receiving Section 12 Optical Sensor 13 Guidance Reflective Tape 13a Straight Section 13b Corner part 14 Control part

Front page continuation (72) Inventor Matsuo Oyama 471-1 Kaizawa-cho, Takasaki-shi, Gunma Sunlights Takasaki 104 Nippon MC Co., Ltd.

Claims (1)

[Claims] 1. A direction sensor for detecting a traveling direction of a machine on the basis of a guide member laid on a conveyance path, and a direction sensor for a traveling machine body which is driven by independently driving left and right drive wheels by a motor. In an automated guided vehicle comprising a traveling control unit for traveling the traveling body along the guide member based on the drive control of the left and right drive wheels corresponding to the detection of, while substantially equalizing the corner radius of the guide member, In the traveling control unit, a straight traveling control mode in which the left and right drive wheels are driven at the same speed and a direction correction mode in which the left and right drive wheels are driven at a predetermined speed ratio are set, and the speed ratio in the direction correction mode is further set, A travel control device for an automated guided vehicle, wherein the travel distance ratio of the left and right drive wheels is made to substantially match when traveling through the corner portion.