JP2001056710A - Control method for unmanned carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform loading in a normal attitude at all the time. SOLUTION: After traveling of a car body is started, a lateral deviation and an attitude angle are calculated on the basis of the output voltages of both detectors, a lateral deviation correction and an attitude angle correction are alternately performed (steps S1 and S2) and when a target loading spot is approached within a prescribed distance, only the attitude angle correction is performed without executing the lateral deviation correction (YES of step S3 and S4) but after the target loading spot is reached, traveling of the car body is stopped (YES of step S5 and S6). Then, the lateral deviation at that time is added to fork moving amount data at that loading spot read out of a main memory (step S7) and loading is performed by moving a fork just for the added moving amount (step S8).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention derives a lateral deviation of a vehicle body in a parallel direction with respect to a guide line provided on a traveling course and a posture angle of the vehicle body with respect to the guide line during traveling. The present invention relates to an automatic guided vehicle control method for correcting a deviation and an attitude angle.

[0002]

2. Description of the Related Art Conventionally, in an automatic guided vehicle, a guide line for guidance is provided along a course to be traveled, and the guide line is detected by detectors attached to the front and rear of the vehicle body, and the guide line of the vehicle relative to the guide line is detected. Deriving the lateral deviation in the parallel direction and the posture angle of the vehicle body with respect to the guide line, and correcting the lateral deviation to correct the derived lateral deviation and the posture angle to correct the posture angle, the driving wheels of the vehicle body You are driving and driving.

At this time, a magnetic induction system or an electromagnetic induction system is generally adopted, and in the case of the former magnetic induction system,
A magnet embedded in order to form a guide line along the traveling course is detected by a magnetic detector provided in front and rear of the vehicle body. In the case of the latter electromagnetic induction type, a guide wire laid along the traveling course ( For example, a low-frequency current flows through the guide line, and the generated magnetic field is detected by a detector including a pickup coil and the like.

Then, the above-described lateral deviation and attitude angle are calculated based on the output voltages of these detectors, and attitude control is performed so that the calculated lateral deviation and attitude angle become zero. Here, the lateral deviation correction and the posture angle correction are not performed at the same time, and the process shifts to the posture angle correction when the lateral deviation becomes substantially zero, and shifts to the lateral deviation correction when the posture angle becomes substantially zero. As described above, the lateral deviation correction and the posture angle correction are alternately performed, and when the vehicle reaches a predetermined cargo handling point, the fork is moved in the left-right direction of the vehicle body to perform cargo handling.

[0005]

However, in the conventional control method, for example, when the vehicle body reaches a predetermined cargo handling point, if the attitude angle is not zero and the vehicle body is tilted with respect to the guide line, the control method remains unchanged. If the fork is moved in this state, the fork will not reach the proper cargo handling position, and the load will be placed diagonally on the loading table or the load will be loaded diagonally on the fork. There is a risk that the cargo will be picked up in this state.

An object of the present invention is to make it possible to always carry out cargo handling in a normal posture.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is to detect a guide line installed on a traveling course by detectors provided before and after the body of an automatic guided vehicle. Based on the outputs of the two detectors, a lateral deviation, which is a shift of the vehicle body in a parallel direction with respect to the guide line, and an attitude angle, which is an inclination of the vehicle body with respect to the guide line in the front-rear direction, are derived and derived. A method of controlling an automatic guided vehicle that drives driving wheels of the vehicle body while performing a lateral deviation correction that corrects a lateral deviation and a posture angle correction that corrects the posture angle. It is characterized in that only the attitude angle correction is performed after approaching within the distance and before reaching the cargo handling point.

According to such a configuration, when the vehicle body approaches within a predetermined distance from the target cargo handling point, only the attitude angle correction is performed until the vehicle reaches the cargo handling point. At this point, the attitude angle, which is the inclination of the vehicle body with respect to the guide line, is corrected to almost zero.

Therefore, even if the cargo is unloaded after arriving at the unloading point, it is possible to prevent the unloading from being performed obliquely as in the related art, and the unloading can always be performed in a normal posture.

Further, according to the present invention, a guide line provided on a traveling course is detected by detectors provided before and after the vehicle body of the automatic guided vehicle, and based on outputs of the two detectors, the guide line with respect to the guide line is detected. A lateral deviation, which is a deviation of the vehicle body in the parallel direction, and a posture angle, which is an inclination of the vehicle body with respect to the guide line, are respectively derived, and the lateral deviation correction and the posture angle for correcting the derived lateral deviation are corrected. Driving the drive wheels of the vehicle body while performing the posture angle correction to make a fork in the left and right direction of the vehicle body by a predetermined amount as a fork moving amount at the predetermined cargo handling point when the vehicle reaches a predetermined cargo handling point. In the control method of an automatic guided vehicle that moves and performs cargo handling, the posture angle may be set before the vehicle body approaches within a predetermined distance from a target cargo handling point and reaches the cargo handling point. Only performed positively, and the fork movement amount at the handling point, thus being moved only the forks amount obtained by adding the lateral deviation detected by the handling point.

By doing so, when the vehicle reaches the target cargo handling point, the attitude angle, which is the inclination of the vehicle relative to the guide line, is corrected to almost zero. When loading, the fork can be prevented from moving diagonally, and there is no danger that the load will be placed diagonally on the loading table or the diagonal load will be loaded on the fork as usual. Cargo handling can be performed in a normal posture.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. 1 to 3 are explanatory diagrams of operations in different states, FIG. 4 is a block diagram, and FIG. 5 is a flowchart.

As shown in FIG. 1, before and after a vehicle body 1 of an automatic guided vehicle traveling in the direction of an arrow, a first
A guide wire 3 provided with a detector 2a and a second detector 2b and formed by burying a magnet along a traveling course.
Are detected by the two detectors 2a and 2b, and a voltage proportional to the detected magnetic flux from the two detectors 2a and 2b is output to the CPU 4 as shown in FIG.

Based on the output voltages of the two detectors 2a and 2b, the CPU 4 calculates a lateral deviation, which is a deviation of the vehicle body 1 relative to the guide line 3 in a parallel direction, and a tilt of the vehicle body 1 with respect to the guide line 3 in the front-rear direction. A calculation unit 5 for deriving a certain attitude angle, a buffer memory 6 including a RAM for temporarily storing calculation data, a ROM 7 storing a control program of the automatic guided vehicle, position data of each loading point, and each loading point A main memory 8 storing various data for unmanned conveyance such as predetermined fork movement amount data at
And a controller 9 that corrects the lateral deviation derived from the above and corrects the attitude angle to correct the attitude angle.

The control section 9 controls the steering section 10 and the drive section 11 so that the steering section 10 controls the steering angle to a predetermined value, and the drive section 11 controls, for example, a power motor to drive the drive wheels. When the vehicle body 1 is driven, the lateral deviation correction and the posture angle correction are performed while the vehicle body 1 is traveling. However, as in the conventional case, when the lateral deviation becomes substantially zero, the process shifts to the posture angle correction, and when the posture angle becomes substantially zero, the process shifts to the lateral deviation correction. It is done alternately.

At this time, as shown in FIG.
When the vehicle body 1 traveling in the direction of the arrow is displaced by L in the parallel direction, it is assumed that the two detectors 2a and 2b have the same characteristics and the output voltages of the two detectors 2a and 2b have the same polarity and the same value. Therefore, the lateral deviation L of the vehicle body 1 with respect to the guide line 3 is determined from the output voltages of the two detectors 2a and 2b at that time.
Can be calculated.

As shown in FIG. 2, when the longitudinal direction of the vehicle body 1 traveling in the direction of the arrow is inclined with respect to the guide line 3, the output voltages of the two detectors 2a and 2b have different polarities and different values. Therefore, the posture angle θa or θb of the vehicle body 1 with respect to the guide wire 3 can be calculated from the output voltages of the two detectors 2a and 2b at that time.

Further, as shown in FIG. 3, when the vehicle body 1 travels in the direction of the arrow and reaches a predetermined cargo handling point, the main memory 8
The fork movement amount data at the cargo handling point stored in the fork moving unit 12 is read by the control unit 9, and the fork moving unit 12 (see FIG. 4) is controlled by the control unit 9, and as shown in FIG. The fork F is moved in the left and right direction of the vehicle body 1 by the fork moving unit 12 by the set amount, and the cargo is unloaded.

When the vehicle body 1 approaches within a predetermined distance of, for example, 5 m from the target cargo handling point, the lateral deviation correction is not performed until the vehicle body 1 reaches the cargo handling point. Is performed, and at the time of reaching the cargo unloading point, the arithmetic unit 5 detects the two detectors 2a and 2b.
The lateral deviation of the vehicle body 1 with respect to the guide wire 3 is calculated from the output voltage of the fork moving unit 12, and the control unit 9 adds the calculated lateral deviation to the fork moving amount at the cargo unloading point. Is controlled so that the fork F is moved.

Here, in order to determine whether or not the vehicle has approached within a predetermined distance from the target cargo handling point, a mark (such as a magnetic mark) is provided in advance at a point a predetermined distance before each cargo handling point, and this mark is separately provided. This can be realized by detecting with a sensor (or one of the detectors 2a or 2b). Further, from the position data of each cargo handling point stored in the main memory 8 and the current position of the vehicle body 1 derived from the traveling distance of the vehicle body 1, it is calculated by calculation which distance the vehicle body 1 is located before the target cargo handling point. It can also be realized by:

Next, the operation will be described with reference to the flowchart of FIG. Now, as shown in FIG. 5, the power motor is driven to start the running of the vehicle body 1 (step S1), and the lateral deviation and the attitude angle are calculated based on the output voltages of the two detectors 2a and 2b. The correction of the lateral deviation and the correction of the attitude angle are alternately performed to make these values zero (step S2).

Subsequently, it is determined whether or not the vehicle has approached the target cargo handling point within a predetermined distance (step S).
3) If the determination result is NO, the process returns to step S2. If the determination result is YES, the vehicle body 1 is corrected so that only the attitude angle is corrected without performing the lateral deviation correction and the attitude angle becomes zero. Is performed (step S4).

Then, it is determined whether or not the vehicle has reached the target cargo handling point (step S5). If the result of the determination is NO, the process returns to step S4, and if the result of the determination is YES, the traveling of the vehicle body 1 is stopped. The operation is stopped (step S6), the fork movement amount data at the cargo unloading point is read from the main memory 8, and the two detectors 2a, 2b at that time are read.
The lateral deviation is calculated based on the output voltage of the fork F, and the calculated lateral deviation is added to the read fork movement amount (step S7), and the fork F moves in the left-right direction of the vehicle body 1 by the added movement amount. And the cargo is carried out (step S
8) Then, the operation ends.

Therefore, according to the above-described embodiment, when the vehicle body 1 reaches the target cargo handling point, the attitude angle, which is the inclination of the vehicle body 1 with respect to the guide line 3, can be corrected to almost zero. When the fork F is moved to carry out cargo handling, the fork F can be prevented from moving diagonally, and the load can be placed diagonally on the cargo handling table, or can be It is possible to always carry out cargo handling in a normal posture without the risk of being loaded.

In the above-described embodiment, an automatic guided vehicle equipped with a fork will be described as an example. After reaching a target cargo handling point, a lateral deviation at that time is added to a predetermined fork movement amount. Although the fork is moved by an amount, the present invention can be applied to an automatic guided vehicle that does not include the fork F. In this case, at least the target cargo handling point is approached to a predetermined distance. In such a case, only the correction of the posture angle needs to be performed, whereby it is possible to prevent cargo handling in an inclined state.

Further, in the above-described embodiment, the case where the magnetic induction method is used as an example has been described. However, the present invention can be similarly applied to the electromagnetic induction method, and the same effect as the above-described embodiment can be obtained. Of course you can.

The present invention is not limited to the above embodiment, and various changes other than those described above can be made without departing from the gist of the present invention.

[0028]

As described above, according to the first aspect of the present invention, when the vehicle body approaches within a predetermined distance from the target cargo handling point, the posture angle is corrected until the vehicle body reaches the cargo handling point thereafter. When the vehicle reaches the cargo handling point, the attitude angle, which is the inclination of the vehicle body with respect to the guide line, is corrected to almost zero. Even if cargo is handled, it is possible to prevent unloading in a state of being inclined as in the past, it is possible to always carry out cargo handling in a normal posture, and to provide a highly reliable automatic guided vehicle. Will be possible.

According to the second aspect of the present invention, when the vehicle body reaches the target cargo handling point, the posture angle, which is the inclination of the vehicle body with respect to the guide line, is corrected to substantially zero. At the point, when the fork is moved by loading and unloading, the fork can be prevented from moving diagonally, and the load is placed diagonally on the loading table as in the past, It is possible to always carry out cargo handling in a normal posture without being loaded, and to provide a highly reliable automatic guided vehicle.

Further, a predetermined fork movement amount is
By moving the fork by an amount that adds the lateral deviation detected at the cargo handling point, the fork can be securely inserted into the load or pallet as far as it will go, and when loading, the fork is stably placed on the fork. The load can be loaded, and at the time of loading, the load can be reliably placed at a fixed position on the loading dock.

[Brief description of the drawings]

FIG. 1 is an operation explanatory diagram in a state according to an embodiment of the present invention;

FIG. 2 is an explanatory diagram of an operation in another state of the embodiment of the present invention.

FIG. 3 is an explanatory diagram of an operation in a different state of the embodiment of the present invention.

FIG. 4 is a block diagram of one embodiment of the present invention.

FIG. 5 is a flowchart for explaining the operation of the embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body 2a, 2b Detector 3 Guide line 4 CPU 5 Operation part 9 Control part 12 Fork moving part F Fork

Continued on the front page F term (reference) 3F333 AA02 AB13 FA04 FA05 FA20 FA23 FA32 FD04 FD07 FD15 FE04 FE05 FE09 5H301 AA01 AA09 BB07 CC03 CC06 EE05 GG11 HH01 HH02 HH03 JJ01

Claims (2)

[Claims] 1. A guide line installed on a traveling course is detected by detectors provided before and after a vehicle body of an automatic guided vehicle, and a longitudinal direction of the vehicle body with respect to the guide line is detected based on outputs of the two detectors. Of the vehicle body with respect to the guide line, and a lateral deviation that is a deviation of the vehicle body with respect to the guide line, and corrects the lateral deviation that is derived and corrects the lateral angle. The method of controlling an automatic guided vehicle that drives the drive wheels of the vehicle body while correcting the attitude angle, wherein the vehicle body approaches within a predetermined distance from a target cargo handling point and then reaches the cargo handling point. A method for controlling an automatic guided vehicle, wherein only an attitude angle correction is performed. 2. A guide line installed on a traveling course is detected by detectors provided before and after the vehicle body of the automatic guided vehicle, and based on outputs of the two detectors, a direction parallel to the guide line with respect to the guide line. The lateral deviation, which is a deviation from the guide line, and the posture angle, which is the inclination of the vehicle body in the front-rear direction with respect to the guide line, are derived, and the lateral deviation correction and the posture angle for correcting the derived lateral deviation are corrected. By driving the drive wheels of the vehicle body while correcting the attitude angle, when the vehicle reaches a predetermined cargo handling point, the fork is moved in the left and right direction of the vehicle body by a predetermined amount set as a fork movement amount at the cargo handling point. In the method for controlling an automatic guided vehicle that performs cargo handling, the posture angle is corrected until the vehicle body approaches within a predetermined distance from a target cargo handling point and reaches the cargo handling point. Carried himself, the fork movement amount at the handling point, the control method of the automatic guided vehicle, characterized by moving only the fork amount obtained by adding the lateral deviation detected by the handling point.