JPH0844430A - Controller for unmanned automated vehicle - Google Patents

Abstract

PURPOSE:To improve the turning performance and traveling stability of an automated vehicle and to improve its follow-up property to a traveling route by providing the vehicle with a specific deviation value detecting means and a control means. CONSTITUTION:In a map M2 in which a correction coefficient alpha for correcting a driving wheel speed in accordance with a deviation is previously set use coefficient alpha is set up so as to be reduced in accordance with the increment of the deviation A in the case of the same turning radius R, the responseness to the correction of an advancing direction can be improved. Namely a follow-up property to a magnetic tape and traveling stability can be improved. Since the rate of change in the coefficient alpha from the deviation DELTA is set up so as to be increased when the deviation DELTA is small, the responseness of control and the follow-up property to the magnetic tape can be improved. Since the rate of change in the coefficient alpha from the deviation DELTA is set up so as to be reduced when deviation DELTA is large, traveling stability and turning performance can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for an automated guided vehicle, and more particularly to a control system with improved turning performance and running stability.

[0002]

2. Description of the Related Art Conventionally, various self-propelled automatic guided vehicles for carrying luggage have been put into practical use. Guide means such as magnetic tape or reflective tape is continuously provided,
It is general that an automatic guided vehicle is provided with a guide detecting means composed of a plurality of detecting elements for detecting the guide means, and the traveling direction of the automatic guided vehicle is controlled based on a detection signal from the guide detecting means.

By the way, the plurality of traveling routes are not necessarily set independently, but are set to traveling routes which partially overlap or intersect each other, and a branching point of the traveling route is used to determine an address. By providing address plates, detecting those address plates with a sensor, etc., and inputting the detection signal to the control unit of the automatic guided vehicle, and by identifying the address from the detection signal, the automatic guided vehicle is set to a predetermined traveling route. Control to run along.

For example, Japanese Unexamined Patent Publication No. 64-25215 has a pair of left and right drive wheels and a pair of left and right coil sensors for detecting a guide wire arranged along a traveling route.
A travel control system for an automated guided vehicle is disclosed in which the travel speed is controlled based on the detection signals of these coil sensors so that the rotational speeds of the left and right drive wheels are speed-differentiated. by the way,
In the conventional control technology for an unmanned guided vehicle, almost no specific proposal has been made regarding the technology for improving the turning performance or the running stability during turning.

[0005]

In the conventional control technology for an automatic guided vehicle, when a relative deviation amount of the vehicle body with respect to the traveling route occurs, a relative speed difference is added to the rotational speeds of the left and right drive wheels to eliminate the relative deviation amount. However, the speed difference between the turning outer wheel and the turning inner wheel is always set uniformly according to the relative deviation amount, regardless of whether the vehicle is traveling straight or traveling. However, when the relative deviation amount is large, especially when the vehicle is traveling in a turning direction where the relative deviation amount is large, if the correction control in which the speed difference changes rapidly with respect to the change in the relative deviation amount is executed, the running stability is reduced and the turning stability is reduced. There is a problem of reduced performance. Also,
When the correction control is performed in which the speed difference rapidly changes with respect to the change in the relative deviation amount when the traveling speed is high, there is a problem that the traveling stability is deteriorated and the turning performance is deteriorated as described above. An object of the present invention is to improve turning performance and traveling stability, enhance followability to a traveling route, and the like in an automatic guided vehicle.

[0006]

A control device for an automatic guided vehicle according to claim 1 has a pair of left and right drive wheels which are independently driven,
In an automatic guided vehicle that automatically travels along the travel route and corrects the relative displacement between the travel route and the vehicle body by the speed difference between the inner and outer wheels of the turning, displacement detection that detects the relative displacement between the travel route and the vehicle body Means and the output of the deviation amount detection means, so that the speed difference change rate with respect to the relative deviation amount when the relative deviation amount is large becomes smaller than the speed difference change rate with respect to the relative deviation amount when the relative deviation amount is small. And a control means for controlling the speed of the pair of left and right driving wheels.

Here, the control means has a control characteristic of decelerating the turning inner wheel with respect to the turning outer wheel, and the deceleration rate of the turning inner wheel due to the relative deviation amount is relatively deviated as compared with when the relative deviation amount is small. A configuration having a control characteristic that is set large when the amount is large may be adopted (claim 2 dependent on claim 1). Further, the control means may be configured to include the control characteristic as a control characteristic that is mapped for each turning radius (claim 3 dependent on claim 2). Further, the mapped control characteristics may be set such that the speed difference change rate with respect to the relative deviation amount becomes smaller as the turning radius becomes larger (claim 4 dependent on claim 3).

[0008]

In the control device for the automatic guided vehicle according to the first aspect of the present invention, the deviation amount detecting means is used to correct the relative deviation amount between the traveling route and the vehicle body by the speed difference between the inner and outer turning wheels. The relative displacement amount between the vehicle body and the vehicle body, and the control means receives the relative displacement amount detected by the displacement amount detecting means,
The speeds of the pair of left and right drive wheels are controlled so that the speed difference change rate with respect to the relative deviation amount when the relative deviation amount is large is smaller than the speed difference change rate with respect to the relative deviation amount when the relative deviation amount is small. To do.

As described above, when the amount of relative deviation is small, such as when traveling straight ahead, the speed of the pair of left and right drive wheels is controlled so that the rate of change in speed difference with respect to the amount of relative deviation is increased, thereby controlling the speed. It is possible to improve the responsiveness and the followability of following the travel route. Further, when the relative deviation amount is large, such as during turning, the speeds of the pair of left and right driving wheels are controlled so that the rate of change in speed difference with respect to the relative deviation amount is reduced, so that traveling stability and turning performance are improved. Can be increased. That is, when the relative deviation amount is large, such as during turning, when the rate of change of the speed difference with respect to the relative deviation amount is increased, the speed difference changes rapidly in accordance with the change in the relative deviation amount. The turning performance will decrease,
This can be prevented.

According to another aspect of the present invention, the control means has a control characteristic of decelerating the inner turning wheel with respect to the outer turning wheel. Since the control characteristic is set to be large when the relative deviation amount is large compared to when the deviation amount is small, the correction for eliminating the relative deviation amount can be achieved through the deceleration control for decelerating the speed of the turning inner wheel. Then, by controlling the deceleration rate of the turning inner wheel via the control characteristic, the followability to follow the traveling route is enhanced.

In the automatic guided vehicle control apparatus according to the third aspect of the present invention, the control means has the control characteristic as a control characteristic that is mapped for each turning radius. Therefore, control is performed with a characteristic according to the turning radius. can do. In the automatic guided vehicle control device according to a fourth aspect of the present invention, the mapped control characteristics are set such that the speed difference change rate with respect to the relative deviation amount decreases as the turning radius increases. Here, in the case of controlling so that the traveling speed becomes higher as the turning radius becomes larger, as described above, by setting so that the speed difference change rate with respect to the relative deviation amount becomes smaller as the turning radius becomes larger, It is possible to improve traveling stability and followability to a traveling route.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, a self-propelled automatic guided vehicle V (hereinafter simply referred to as a guided vehicle) is for automatically carrying mechanical parts and the like in a factory. A plurality of predetermined traveling routes are set, guide means that are continuous over the entire length are laid on the floor of each traveling route, and each point is identified at multiple points along the traveling route. A number plate for laying is laid.

A loading section 2 for loading luggage M is provided on the upper surface of the vehicle body 1 of the transport vehicle V. Inside the vehicle body 1, a battery 3 as a driving energy source and a control unit 4 are housed, and the vehicle body 1 A bumper 5 is attached to the front end of the vehicle body 1, and a pair of left and right drive wheels 6 is provided in the center of the front portion on the lower surface side of the vehicle body 1.
A drive wheel unit 8 having a and 6b and electric motors 7a and 7b directly connected to the drive wheels 6a and 6b is rotatable about a vertical axis and rotatable about a horizontal axis in the vehicle longitudinal direction. The left and right driven wheels 9a and 9b are provided at the rear end of the vehicle body 1 on the lower surface side.

Further, on the lower surface side of the vehicle body 1, there are provided a first sensor 11 located on the front side of the drive wheel unit 8 for detecting guide means, and a second sensor 12 for detecting the address plate. Is provided. The guide means is
The surface of a magnetic tape 13 having a width of about 5 cm is covered with a protective tape, and the first sensor 11 has the structure shown in FIG.
As shown in FIG. 6, 16 Hall elements 11a are arranged in the vehicle width direction, and 5 of the 16 Hall elements 11a face the magnetic tape 12.

As shown in FIG. 4, the address plate 14 has a magnetic tape piece 14a and a non-magnetic non-magnetic tape piece 14b, which are arranged in various patterns in the traveling direction of the carrier vehicle V. The magnetic tape pieces 14a and the non-magnetic tape pieces 14b are arranged so as to correspond to one Hall element, respectively. As shown in FIG. 5, the second sensor 12 has a structure in which ten Hall elements 12a are arranged in the traveling direction of the transport vehicle V.
The start and end of the reading of the detection signal are detected by the Hall elements 12a at the front and rear ends, and the address is determined from the 8-bit detection signals of the eight central Hall elements 12a.

Next, the control system will be described. As shown in FIG. 6, the control unit 4 includes an input / output interface 20, a microcomputer including a CPU 21, a ROM 22 and a RAM 23, and electric motors 7a and 7b, which are DC motors that drive the left and right drive wheels 6a and 6b, respectively. Drive circuits 24a and 24b of the first sensor 11 are provided.
Detection signal Gi (i = 1 to 16) from the second sensor 12
Detection signal Bj (j = 1 to 10) is input to the microcomputer via the input / output interface 20, and an operation signal from the operation panel 25 is input to the microcomputer via the input / output interface 20. In addition, the power from the battery 3 is supplied to the drive circuit 24a,
24b, and these drive circuits 24a and 24b are
Electric motor 7a for left drive wheel and electric motor 7 for right drive wheel
connected to b respectively.

In the ROM 22 of the microcomputer, a control program for controlling a driving wheel speed, which will be described later, for controlling the traveling direction of the carrier vehicle V, and an address table and a map associated therewith are input and set in advance. The RAM 23 is provided with various work memories. Explaining the address table, the stop point of the traveling route,
Acceleration start point, deceleration start point, straight ahead start point, left turn start point,
An address plate 14 is provided on the floor side at the right turning start point and the like, and a series of address numbers is given to each of these points, and R
In the address table 26 of the OM 22, for example, as shown in FIG. Required data regarding acceleration start, deceleration start, stop, straight ahead start, left turn start, right turn start, turning radius, etc. is set in advance.

Therefore, the detection signal Bj of the second sensor 12
When the address is determined from (j = 1 to 10), based on the data of the address table 26 corresponding to the address, acceleration start, deceleration start, stop, straight start, left turn required for drive wheel speed control. It is configured to obtain data regarding the start, the right turn start, the turning radius, and the like.

The microcomputer controls the drive current by the PWM method, and the drive circuits 24a and 24b are used.
Is provided with an amplifier circuit for controlling a drive current based on a control signal from a microcomputer and a circuit shown in FIG. 8 (excluding the motors 7a and 7b). In the circuit of FIG. 8, the forward switches 30a and 30b are turned off.
N, when the reverse switches 31a and 31b are OFF,
The drive current Di is supplied to the electric motors 7a and 7b to drive the electric motors 7a and 7b in the normal direction to drive the drive wheels 6a and 6b in the forward direction, and the reverse switch 31.
a and 31b are ON and forward switches 30a and 30b are O
At the time of FF, the electric motors 7a and 7b are reversely driven and the drive wheels 6a and 6b are reversely driven in the backward direction. Also,
Forward switches 30a, 30b and reverse switch 31
a and 31b are OFF, brake switch 33 is ON
At this time, the electric motors 7a and 7b are connected via the load resistor 34.
Is in a braked state.

Next, an outline of the drive wheel speed control will be described. FIG. 9 shows a map M1 of the drive wheel speed basic value Vo stored in the ROM 22 in advance. During turning, it is necessary to reduce the wheel speed of the inner turning wheel with respect to the wheel speed of the outer turning wheel. It is necessary to set the deceleration rate of 1 based on the turning radius R and the interval between the left and right drive wheels 6a and 6b so that the deceleration rate increases as the turning radius R decreases. When the wheel speed of the outer turning wheel is controlled to be constant regardless of the turning radius R, the wheel speed of the outer turning wheel and the wheel speed of the inner turning wheel are shown by chain lines. However, since it is desirable to reduce the traveling speed as the turning radius R becomes smaller,
In the present embodiment, the wheel speed of the outer turning wheel increases as the turning radius increases, and the wheel speed basic value of the outer turning wheel becomes constant so that the turning radius becomes constant at 7.5 m or more and in a straight traveling state. V0 is set as shown by the solid line, and the wheel speed basic value V0 of the turning inner wheel is set as shown by the solid line based on the turning radius R and the interval between the left and right driving wheels 6a, 6b.

As shown in FIG. 10, the carrier V is displaced to the left with respect to the magnetic tape 13, and the center positions Pcen of the five ON Hall elements of the first sensor 11 are aligned with the center line C of the vehicle body.
Deviation Δ deviated from L (center position of the first sensor 11)
As shown in FIG. 10, when the deviation Δ> 0, the right drive wheel 6b is decelerated so that the center position Pcen coincides with the vehicle body center line CL, and when the deviation Δ <0, the center position Pcen is changed. The left driving wheel 6a is decelerated so as to match the vehicle body center line CL.

FIG. 11 shows a map M2 in which a correction coefficient α for correcting the drive wheel speed is preset according to the deviation Δ, and when the absolute value of the deviation Δ is a predetermined value δ or less, the correction is made as a dead zone. The coefficient α is set to 1.0, the correction coefficient α decreases as the turning radius R decreases, and the correction coefficient α increases as the absolute value of the deviation Δ increases when the turning radius R is constant. It is set to be small. Further, when the vehicle is traveling straight ahead, the traveling speed is large and the effect of the correction by the correction coefficient α appears earlier. Therefore, the correction coefficient α is set to be larger than that when the vehicle is traveling.

Further, the correction coefficient α of the map M2 has a deviation Δ
The rate of change of the correction coefficient α with respect to the deviation Δ when the absolute value of the deviation Δ is large is smaller than the rate of change of the correction coefficient α with respect to the deviation Δ when the absolute value of is small, Further, the correction coefficient α is set for each turning radius R, and is set such that the rate of change of the correction coefficient α with respect to the deviation Δ decreases as the turning radius R increases. Further, for example, when turning to the right (the right drive wheel 6b becomes the turning inner wheel), the vehicle body 1 tends to shift to the left side with respect to the magnetic tape 13, that is, the deviation Δ> 0. In view of this, the correction coefficient α is set to have a characteristic that the deceleration rate of the turning inner wheel due to the occurrence of the deviation Δ is larger when the deviation Δ is larger than when the deviation Δ is small.

In this drive wheel speed control, the map M1
The driving wheel speed basic value V0 is calculated by the following, the deviation Δ is calculated, the correction coefficient α corresponding to the deviation Δ is calculated by the map M2, and the driving wheel speeds VL and VR of the left and right driving wheels 6a and 6b are calculated. Based on the drive wheel speeds VL and VR, the rotational speed (that is, drive torque) of the left and right drive wheel drive electric motors 7a and 7b is controlled.

Next, regarding the drive wheel speed control routine,
This will be described with reference to the flowcharts of FIGS. In the flow chart, the symbol Si (i = 1, 2, 3
... indicates each step. According to FIG. 12, the main routine of the drive wheel speed control is performed, and a predetermined minute time (for example,
The main routine executed every 8 ms) will be described. The detection signal Gi of the first sensor 11 (i = 1 to 16)
Also, the detection signal Bj (j = 1 to 10) of the second sensor 12 is read (S1), and the detection signal Bj is all OFF during traveling at a point without the address plate 14. The detection signal Bj is erased (S2, S3), and the valid detection signals Gi, Bi are stored in the memory of the RAM 23 (S4). That is, the detection signal G read every moment
Although i is stored in the memory while being updated, as for the detection signal Bj, only the valid detection signal Bj read from the latest address plate 14 (last address plate 14) is stored in the memory while being updated.

Next, the address table 26 is searched based on the detection signal Bj to obtain the latest address No. Is calculated (S5), and the address No. Address table 2 corresponding to
From the data of 6, it is known whether the vehicle is currently accelerating, decelerating, stopping, going straight, turning left, turning right, or the like. Next, the calculation processing of the deviation Δ is executed (S6), which will be described later. Next, if the vehicle is traveling straight (S7: Yes)
), From the drive wheel speed basic value V0 for straight traveling of the map M1,
The left and right drive wheel speed basic values V0 are calculated (S8), and then
Applying the deviation Δ to the map M2, when the deviation Δ> 0, the correction coefficient α for the right driving wheel is calculated, and the deviation Δ <
When it is 0, the left driving wheel correction coefficient α is calculated (S
9). Next, the left and right drive wheel speeds VL and VR are calculated based on the drive wheel speed basic value V0 and the correction coefficient α (S1).
0).

For example, when the deviation Δ> 0 as the driving wheel speed basic value V0, the left driving wheel speed VL = V0 and the right driving wheel speed VR = V0 × α, and when the deviation Δ <0,
The left drive wheel speed VL = V0 × α and the right drive wheel speed VR = V0. However, while traveling in the acceleration section or the deceleration section, the left and right drive wheel speeds VL and VR are adjusted so as to accelerate and decelerate at a predetermined acceleration / deceleration rate.
Is corrected for acceleration / deceleration. Next, the left and right drive wheel speeds VL and VR
The control signals for controlling the drive currents of the electric motors 7a and 7b for driving the left and right drive wheels 6a and 6b are calculated based on the above, and the control signals are output to the drive circuits 24a and 24b, respectively (S15). , Then return.

During turning (S7: No), the latest address No. The turning direction and the turning radius R are calculated based on the data of the address table 26 (S11), and then the turning direction and the turning radius R are applied to the map M1 to obtain the left and right driving wheel speed basic values V0. It is calculated (S12). Next, the deviation Δ is applied to the map M2. When the deviation Δ> 0, the right driving wheel correction coefficient α is calculated, and when the deviation Δ <0, the left driving wheel correction coefficient α is calculated. (S1
3). Next, the left and right driving wheel speeds VL and VR are calculated based on the left and right driving wheel speed basic value V0 and the correction coefficient α (S14). Next, based on the left and right driving wheel speeds VL and VR, the electric motor 7 that drives the left and right driving wheels 6a and 6b, respectively.
The control signals for drive current control of a and 7b are calculated, and the control signals are output to the drive circuits 24a and 24b, respectively (S
15) and then return.

Next, the subroutine of the deviation Δ calculation processing of S6 will be described with reference to the flowcharts of FIGS. As shown in FIG. 10, 1 of the first sensor 11
In order to specify and weight the positions of the six Hall elements 11 a, the six Hall elements 11 a are sequentially numbered 1 to 16 from the left side.
, The counter i corresponding to this weighting index is first set to 1 (S20), and then the detection signal Gi is set to O.
If it is N (S21), the judgment is No (S21: No), the counter i is incremented (S22), S21 is repeated, and when the detection signal Gi is ON (S21: Yes), the left end The value of i is given to the element number Lno (S23), and the leftmost element number Lno, which is the weighting index of the leftmost hall element 11a of the Hall elements 11a of the first sensor 11 that is turned on, is thus obtained. However, in the example shown in FIG. 10, the leftmost element number L
no = 8.

Similar to the above, the right end element number Rno is obtained as follows by sequentially searching from the right end side. The counter i is set to 16 (S24), and then it is determined whether the detection signal Gi is ON (S25).
When No, decrement the counter i (S2
6) and S25 are repeated, and when the detection signal Gi is ON, the value of the counter i is added to the right end element number Rno (S27), and thus, the most Hall element 11a of the first sensor 11 that is ON. The rightmost element number Rno, which is the weighting index of the right Hall element, is obtained. In the example shown in FIG. 10, the leftmost element number Rno = 12. Next, the width W from the leftmost element number Lno to the leftmost element number Rno is calculated as W = (Rno-Lno) and stored in the memory (S28).

The following steps S29 to S33 are the arithmetic processing for obtaining the total number of the hall elements 11a which are ON. The counter i is set to 1 and the counter Nt for counting the number of hall elements 11a which are ON is set to 0. From (S29), it is determined whether the detection signal Gi is ON (S30), and the determination is Yes.
In the case of, the counter Nt is updated to (Nt + 1) (S31), and it is then determined whether i = 16 (S32).
When <16, the counter i is incremented (S33) and S30 and subsequent steps are repeated, and when the determination in S30 is No, S31 is skipped and S32 is executed. In this way, from i = 1 to i = 16, When it is repeated, the total number of Hall elements 11a that are ON is calculated as Nt, and after the processing up to i = 16 is completed, the process proceeds to S34.

Next, the latest address No. Based on the data of the address table 26 corresponding to, it is determined whether the vehicle is turning left, turning right, or going straight (S34 to S36). When it is going straight, the process proceeds to S37 and the vehicle is turning left. Sometimes S45
When the vehicle is turning right, the process proceeds to S48. If the vehicle is traveling straight ahead, the first calculation step S37 to S44
A plurality of Hall elements 11 among the sensors 11 that are turned on
The center position Pcen, which should be called the center of gravity of a, is calculated. This will be described. First, the leftmost element number Lno is calculated.
It is determined whether the width W from the left end element number Rno to the left end element number Rno is larger than a straight-moving threshold value Wsno which is a predetermined variable constant (S
37) If the result of the determination is Yes, it is highly possible that the influence of noise such as iron pieces falling on the road surface or the point where the magnetic tape 13 intersects is erroneously detected. Return to S1.

When the determination in S37 is No, it is turned on.
It is determined whether or not the total number of the Hall elements 11a being operated is larger than the threshold value Wtno for branch intersection determination which is a predetermined variable constant (S38). If the determination is Yes, the magnetic tape 13 Since there is a high possibility that it is a branch point or an intersection, the process returns from S37 to S1 of the main routine. That is, at the branch point of the traveling route, as shown in FIG. 16, since the magnetic tape 13 is branched, the number of Hall elements 11a that are turned ON becomes abnormally large. In this case, the detection signal Gi is driven. This is to eliminate application to wheel speed control. If the determination in S37 is No and the determination in S38 is No, there is a low possibility that it is erroneously detected or there is a possibility that it is a branch point or an intersection, so in S39 to S43, the Hall element 11a that is turned on is The total value Sm of the weighting indexes is calculated.

That is, the counter i is 1, and the total value S
When m is set to 0 (S39), the detection signal Gi is ON (S40: Yes), the total value Sm is updated to (Sm + i) (S41), and when i <16 (S42: N).
o), the counter i is incremented (S43),
After S40 is repeatedly executed, the total value Sm from i = 1 to i = 16 is calculated, and then S44 is executed.
At, the center position Pcen is calculated as Pcen = Sm / Nt, and the process proceeds to S51.

When the vehicle is making a left turn, it is judged whether or not the total number of Hall elements 11a that are ON is larger than the branch intersection judgment threshold value Wtno (S45), and the judgment is Yes. In case of, similarly to the above, the process returns from S45 to S1 of the main routine. If the determination in S45 is No, it is unlikely that it is a branch point or an intersection, so the center position Pcen is calculated as Pcen = (Lno + 3) (S46), and then the detection signal Bj stored in the memory.
To address No. Is calculated, and the address No. The turning radius is calculated based on the data of the address table 26 corresponding to (S47), and then the process proceeds to S51.

Similarly, when the vehicle is making a right turn, it is determined whether or not the total number of Hall elements 11a that are turned on is larger than the branch intersection determination threshold value Wtno (S4).
8) If the determination is Yes, S48 is performed in the same manner as above.
Returns to S1 of the main routine. If the determination in S48 is No, it is unlikely that it is a branch point or an intersection, so the center position Pcen is calculated as Pcen = (Rno-3) (S49), and the detection stored in the memory is then detected. From the signal Bj to the address No. Is calculated, and the address No. The turning radius is calculated based on the data of the address table 26 corresponding to (S50), and then the process proceeds to S51.

Next, in S51, the previous center position Pcen
(k-1) and the current center position Pcen (k) from the center position Pcen
Change rate DP is calculated, and then it is determined whether the change rate DP is equal to or greater than a predetermined value K0 (S52).
If s, it is determined whether the vehicle is going straight (S53). When the vehicle is traveling straight (S53: Yes), it is highly possible that the change rate DP has increased due to the influence of noise such as iron pieces on the road surface.
Since it is not preferable to perform the drive wheel speed control using the current detection signal Gi (i = 1 to 16), the drive speed control based on the current detection signal Gi is stopped, and the process returns to S1 of the main routine. During the turn, the change rate DP often becomes large, and the current detection signal Gi (i = 1 to 16)
Since it is desirable to control the drive wheel speed using
Move to 54. If the determination in S52 is No,
Skip S53 and move to S54. In S54,
The center position Pce with respect to the vehicle body center line CL of the carrier vehicle V
The deviation Δ of n is calculated as Δ = (Pcen −8.5).

Next, the operation of the drive wheel speed control of the automatic guided vehicle described above will be described. Regarding the calculation process for obtaining the center position Pcen of the Hall element 11a that is turned on, when the vehicle is traveling straight, the total value Sm of the weighting indexes is divided by the total number Nt to calculate the center position Pcen.
It is possible to improve the accuracy of obtaining the center position Pcen and the accuracy of the drive wheel speed control. In particular, for example, as the weighting index, for example, 1, 1, 2, 2, 4, 4, 4, 6, 8, 10,
By setting as 8, 6, 4, 4, 2, 2, 1, the total value Sm of the five Hall elements 11a on the center side becomes large, so that the influence of noise can be easily eliminated. Also,
When turning, as in S46 and S49, the center position P
Since cen is obtained, it is possible to accurately obtain the center position Pcen by eliminating the influence of the branch points and intersections of the traveling route. Then, in this way, the center position P obtained with high accuracy is obtained.
The deviation Δ can be accurately obtained based on cen.

On the other hand, as shown in the map M1, the turning radius R
And the distance between the left and right driving wheels 6a and 6b, the driving wheel speed basic value V0 of the outer turning wheel and the inner turning wheel is increased so that the driving wheel speed basic value V0 increases as the turning radius R increases. Since the accuracy is set, it is possible to maintain the traveling speed as high as possible, ensure the turning performance and the traveling stability during turning, and improve the accuracy of the drive wheel speed control.

As shown in the map M2, as the characteristic of the correction coefficient α, in the case of the same turning radius R, the correction coefficient α is set to be smaller as the deviation Δ is larger.
Increasing the response of traveling direction correction, that is, magnetic tape 1
It is possible to enhance the followability with respect to 3 and enhance the running stability. Correction coefficient α for deviation Δ when deviation Δ is small
The change rate of the correction coefficient α with respect to the deviation Δ when the deviation Δ is large can be improved by increasing the control response and the followability with respect to the magnetic tape 13. Is set to be small, it is possible to improve running stability and turning performance. That is, if the change rate of the correction coefficient α with respect to the deviation Δ is increased when the deviation Δ is large, such as during turning, the speed difference between the turning outer wheel and the turning inner wheel changes rapidly according to the change in the deviation Δ. Although running stability and turning performance are reduced, this can be prevented.

In view of the fact that the traveling speed becomes slower as the turning radius R becomes smaller, a characteristic line is set for each turning radius R, and the correction coefficient α is set to become smaller as the turning radius R becomes smaller. , For each turning radius R, while keeping the running speed as high as possible, to ensure the turning performance and running stability during turning,
The traveling direction can be accurately controlled. Further, in consideration of the fact that the transport vehicle V shifts toward the outer wheel on the side of the magnetic tape 13 during turning, the deceleration rate of the inner wheel on the turn is deviated by a deviation Δ.
Since the deviation Δ is set larger when the deviation Δ is larger than when the deviation Δ is small, correction control for eliminating the deviation Δ can be achieved through deceleration control for decelerating the speed of the turning inner wheel, and the followability to the magnetic tape 13 is enhanced. be able to.

Further, as shown in the map M1, in consideration of the fact that the traveling speed becomes higher as the turning radius R becomes larger, the change rate of the correction coefficient α with respect to the deviation Δ becomes smaller as the turning radius R becomes larger. Since it is set, running stability can be enhanced and followability to the magnetic tape 13 can be enhanced. The correction coefficient α for straight running where the traveling speed is higher than that for turning is the correction coefficient α for turning.
Since it is set to be larger than that, it is possible to prevent the occurrence of hunting, enhance the followability to the magnetic tape 13, and enhance the running stability.

By providing the steps S37 and S38, it is possible to eliminate the control based on the abnormal detection signal at the branch point or the intersection of the traveling route and prevent the deterioration of accuracy. This also applies to steps S45 and S48. Further, steps S52 and S53 are provided so that when the rate of change DP of the center position Pcen is equal to or greater than a predetermined value K0 and the vehicle travels straight, the calculation of the deviation Δ is stopped and the drive wheel speed control based on the detection signal Gi is not performed. Therefore, it is possible to prevent the accuracy of the drive wheel speed control from being lowered due to the influence of noise or the like. However, since the change rate DP may be equal to or greater than the predetermined value K0 during turning, the calculation of the deviation Δ and the subsequent calculation of the correction coefficient α are performed to correct the traveling direction. It is possible to prevent the accuracy of the direction correction from decreasing.

Next, a description will be given of a modified mode in which the subroutine for the calculation processing of the deviation Δ is modified (FIGS. 17 to 1).
9). As shown in FIG. 17, in view of the fact that the center position Pcen cannot be accurately obtained when, for example, two Hall elements 11a are turned on due to the influence of noise such as iron pieces falling on the road surface, In this modified mode, as shown in the figure, among the Hall elements 11a that are turned on, one or a plurality of Hall elements 11a that are arranged adjacently and continuously are regarded as one block, and the first block and the second block
The block is divided into a plurality of blocks like a block, and the deviation Δ is calculated based on the plurality of detection signals Gi of the widest block.

In FIGS. 18 and 19, first, a counter i corresponding to the weighting index of the Hall element 11a.
(I = 1 to 16) is set to 1, and the block counter k
Is set to 0 (S60), and then the detection signal Gi is turned on.
Then, the detection signal G (i-
1) is OFF (S61: Yes, S62: Yes)
), The block counter k is incremented (S63), the left end element number Lno (k) of the block is calculated as Lno (k) = i (S64), and then i = 16. It is determined whether or not (S6
5) If the determination is No, the counter i is incremented (S66) and S61 and subsequent steps are repeated.
In this way, the leftmost element number Lno (1) of the first block
, The leftmost element number Lno (2) of the second block is calculated, and when i = 16 (S65: Yes), the number of blocks B
No is set as Bno = the value of the final block counter k (S67).

Next, in S68 to S74, i = 16
When the number of blocks Bno = 2, the rightmost element numbers Rno (2) and Rno (1) of each block are sequentially calculated for 1 to 1. That is, first, the counter i is set to 16 and the counter k is set to 0 (S68), then the detection signal Gi is ON, and the detection signal G (i + 1) of the Hall element 11a on the right side of the detection signal Gi is one. Is OFF (S69: Yes, S70: Yes), the right end element number Rno (Bno-k) of the rightmost block is changed to Rno (Bno
-K) = i is calculated (S71), then the counter k is incremented (S72), then it is judged whether i = 1 (S73), and when the judgment is No, the counter i is decremented. (S74) and S69 and subsequent steps are repeated, and when i = 1, the process proceeds to S75.

Next, in S75 to S78, the width W (k) from the left end element number Lno (k) to the right end element number Rno (k) in each block is calculated. That is, first, the block counter k is set to k = 1 (S75), and then the width W (k) from the left end element number Lno (k) to the right end element number Rno (k) is W (k). = Rno (k) -Lno (k) (S76), and then counter k <number of blocks B
If no (S77: No), the counter k is incremented (S78) and S76 and subsequent steps are repeated until the counter k = the number of blocks Bno (S77: Yes), S
Move to 79.

S79 to S84 are arithmetic processes for detecting a block having the maximum width, and the block counter k is set to 1 at first.
And the maximum width Wm is set to 0 (S7
9) Next, it is determined whether or not the width W (k) of the kth block is larger than the maximum width Wm (S80). If the determination is Yes, the maximum width Wm is set to the width W (k of the kth block. k) is added (S81), and then the value of the counter k is added to the maximum width block number Mno (S82). However, when the determination in S80 is No, S81 and S82 are skipped and the process proceeds to S83.

In S83, it is determined whether or not the block counter k = the number of blocks Bno. If the determination is No, the block counter k is incremented (S84), and S
After 80 is repeated and the block counter k = the number of blocks Bno (S83: Yes), the center position Pcen of the block having the maximum width obtained in S85 is
It is calculated as Pcen = [Rno (Mno) -Lno (Mno)] / 2. For example, as shown in FIG. 18, when the first block has the maximum width, Pcen = [Rno (1)
-Lno (1)] / 2 will be calculated. Next, in S86, the deviation Δ is Δ = (Pcen −8.5)
Is calculated as The deviation Δ obtained in this way is used as a map M
The correction coefficient α is calculated by applying the above to No. 2. In this modification, the Hall element 11 turned on is
From the array pattern of a, the Hall element 11a operated by noise such as an iron piece is detected, the Hall element 11a operated by the noise is excluded, the center position Pcen is calculated, and the deviation Δ
Is equivalent to computing.

In the drive wheel side control using the deviation Δ obtained by the above deviation calculation processing, the center position Pcen of the plurality of Hall elements 11a belonging to the block having the maximum width among the plurality of blocks is obtained, and the center position Pcen is obtained. Since the deviation Δ is calculated from, the influence of noise such as iron pieces is surely eliminated,
Since the deviation Δ can be obtained with high accuracy, the accuracy of the drive wheel speed control, that is, the traveling direction control can be sufficiently improved.

A modified mode in which the above embodiment is partially modified will be described. 1] As the guide means, various guide means other than a magnetic tape can be applied, and in that case, guide detection means that can detect the guide means is applied. 2] In the deviation calculation process according to the modification, the total value of the weighting indexes of one or a plurality of Hall elements 11a in each block is calculated, and the center position Pcen is calculated only for the maximum of the total values. You may comprise. However, as the weighting index in this case, for example, 1, 1, 2, 2, 4, 4, 4, 6, 8, 10, 8, 6, 6, in order from the left side of the 16 Hall elements 11a as described above.
Central element 11 such as 4, 4, 2, 2, 1
It is set so that the weights of the Hall elements 11a on both end sides are smaller than the weight of a.

3] In the above embodiment, the description of the brake control for the driving electric motors 7a and 7b is omitted, but when the correction coefficient α becomes 0 according to the map M2, the corresponding driving control is performed. Regarding the motor, the forward movement switches 30a and 30b and the backward movement switches 31a and 31b shown in FIG. 8 may be turned off and the braking switch 33 may be turned on to exert a braking action.

[Brief description of drawings]

FIG. 1 is a cross-sectional plan view of an automated guided vehicle according to an embodiment of the present invention.

FIG. 2 is a side view of the automatic guided vehicle of FIG.

FIG. 3 is an explanatory diagram of a configuration of a first sensor.

FIG. 4 is an explanatory diagram of a configuration of an address plate.

FIG. 5 is an explanatory diagram of a configuration of a second sensor.

FIG. 6 is a block diagram showing a configuration of a control system.

FIG. 7 is a diagram for explaining the contents of an address table.

FIG. 8 is a circuit of an electric circuit included in a driving circuit.

FIG. 9 is a diagram of a map M1 in which a drive wheel speed basic value V0 is set.

FIG. 10 is an explanatory diagram illustrating a first sensor, a magnetic tape, a deviation Δ, and the like.

FIG. 11 is a diagram of a map M2 in which a correction coefficient α is set.

FIG. 12 is a flowchart of a drive wheel speed control routine.

FIG. 13 is a part of a flowchart of a subroutine of deviation calculation processing.

FIG. 14 is a part of a flowchart of a subroutine of deviation calculation processing.

FIG. 15 is the rest of the flowchart of the subroutine of deviation calculation processing.

FIG. 16 is an explanatory diagram exemplifying an operating state of a first sensor at a branch portion of a traveling route.

FIG. 17 is an explanatory diagram exemplifying an operating state of the first sensor in which an influence of noise or the like is apparent.

FIG. 18 is a part of a flowchart of a subroutine of deviation calculation processing according to a modification.

FIG. 19 is the rest of the flowchart of the subroutine of the deviation calculation process according to the modification.

[Explanation of symbols]

 V Automated guided vehicle 1 Vehicle body 4 Control unit 6a, 6b Left and right drive wheels 7a, 7b Driving electric motor 11 First sensor 12 Second sensor 13 Magnetic tape 14 Address plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroki Morio 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Motor Corporation

Claims (4)

[Claims] 1. An unmanned conveyance system having a pair of independently driven left and right driving wheels, automatically traveling along a traveling route, and correcting a relative deviation amount between the traveling route and a vehicle body by a speed difference between a turning inner and outer wheels. In a vehicle, a deviation amount detecting means for detecting a relative deviation amount between the traveling route and the vehicle body, and an output of the deviation amount detecting means are compared with a speed difference change rate with respect to the relative deviation amount when the relative deviation amount is small. A controller for an automatic guided vehicle, comprising: a control unit that controls the speeds of the pair of left and right driving wheels so that the rate of change in speed difference with respect to the relative deviation amount becomes small when the relative deviation amount is large. . 2. The control means has a control characteristic of decelerating the turning inner wheel with respect to the turning outer wheel, and a deceleration rate of the turning inner wheel associated with the relative deviation amount is smaller than that when the relative deviation amount is small. The control apparatus for the automatic guided vehicle according to claim 1, wherein the control characteristic is set to a large value when the value is large. 3. The control device for an automated guided vehicle according to claim 2, wherein the control means is provided with the control characteristic as a control characteristic that is mapped for each turning radius. 4. The automatic guided vehicle according to claim 3, wherein the mapped control characteristics are set such that the rate of change in speed difference with respect to the relative deviation amount becomes smaller as the turning radius becomes larger. Control device.