JPH0212411A - Steering device for magnetic induction type unmanned carrier - Google Patents

Abstract

PURPOSE:To enable a carrier to smoothly pass a branching point by adding a signal delay element to a shift signal generating circuit to give a delay characteristic to the shift signal which is obtained by detecting a shift mark at the branch point of a running route. CONSTITUTION:When the carrier detects the shift mark on the running route to turn on a shift switch 5R, the operation signal of the shift switch 5R has the polarity inverted by an inverting amplifier 10 and is inputted to an amplifier 8 through resistors R3 and R7 as a negative shift signal (-) controlled by a variable resistor VR2. In this case, the shift signal has a delay characteristic by a capable C2 as the delay element and slowly rises. Simultaneously, the operation signal of the shift switch 5R is inputted to an OR circuit 16 to turn on a contactless switch 15. Consequently, the output of the magnetic sensor is approximately cancelled by the shift signal, and the steering signal is about zero in the pass area of the branch point. Thus, the carrier is run along a guide magnetic tape 2a of the branch at a stable attitude without meandering.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a steering device for a magnetically guided automatic guided vehicle.

[Conventional technology]

In recent years, unmanned transportation systems have been widely adopted in response to the automation of production processes. In addition, the optical reflection method 5I61 is used as a trackless guidance method for guided vehicles in unmanned transportation systems.
The latter type of magnetic induction method is known as a method in which traveling is controlled while a magnetic sensor mounted on the transport vehicle detects an induction magnetic tape laid on the floor along the travel route of the transport vehicle. It is being In addition, when using such a magnetic induction method, if the travel route of the transport vehicle branches in the middle, a shift mark such as a magnetic plate, for example, is placed on the guiding magnetic tape at the branching point to indicate the direction of travel of the transport vehicle. This is detected by a shift switch such as a proximity switch mounted on the transport vehicle, and a shift signal with a polarity corresponding to the shift direction of the transport vehicle is generated based on the operation signal of the shift switch. A system has been adopted in which a steering signal obtained by adding the above-mentioned magnetic sensor to the output signal is used as a steering signal to control the steering of the guided vehicle.

Next, an overview of the above-mentioned magnetically guided automatic guided vehicle and its steering device will be explained with reference to the drawings. First of all, in Figures 5 and 6, 1 is a transport vehicle, 2 is an induction magnetic tape laid on the floor side along the travel route of the transport vehicle 1, and 3 is a branch point of the travel route in the direction of travel of the transport vehicle. Shift marks are correspondingly placed on either the left or right side of the magnetic guiding tape 2. Here, the transport vehicle 1 has left and right driving wheels 1a, lb, and a drive motor lc for the driving wheels.

1d, is equipped with auxiliary wheels 1e, and a magnetic sensor 4 for detecting the magnetic induction tape 2 is located at the center of the tip of the cart, and shift marks are provided at the left and right ends of the cart opposite to the shift mark 3 on the floor side. Shift switches 5L and 5R are provided as proximity switches that detect and operate the shift switches 5L and 5R.

In addition, the traveling and steering control system of such a conveyance vehicle is shown in FIG.
Further, the output characteristics of the magnetic sensor 4 are shown in FIG. In normal straight running conditions, the drive motors lc and ld operate on the left and right driving wheels 1a and 1 according to a preset speed command.
b (Fig. 5) at the same rotational distance and travels straight. Also, in this state, if the transport vehicle sways to the left or right to deviate from the traveling route for some reason, the relative position between the guiding magnetic tape 2 and the trolley will be displaced, causing the output of the magnetic sensor 4 as shown in Fig. 8. , since the polarity changes, a steering signal corresponding to the output change is outputted from the steering circuit 6 of FIG. 7 and added to the speed command value, thereby increasing the speed of one of the left and right drive wheels.

Correct the traveling direction by decelerating the other 0 For example, if the guided vehicle shifts to the right while traveling, the output of the magnetic sensor becomes (-), and the drive motor of the right driving wheel adds a steering signal with reversed polarity to the speed command value. The drive motor of the left driving wheel is conversely subtracted and decelerated, as a result of which the conveying vehicle corrects its direction to the left and runs along the guiding magnetic tape.

On the other hand, when the guided vehicle 1 reaches a branching point on the traveling route, it detects the shift mark 3 indicating the shift direction to the left or right, activates either the shift switch 5L or 5R, and at the same time curves to the right or left. The output and polarity of the magnetic sensor change in accordance with the displacement of the relative position between the guiding magnetic tape 2 and the magnetic sensor 4. In addition, the steering circuit 6 operates the transport vehicle 1 based on the operation signal of the shift switch 5L or 5R.
A shift signal with a polarity corresponding to the shift direction is generated, and this shift signal is added to the output signal of the magnetic sensor 4, and the result is output as a steering signal. Then, by controlling the steering by speeding up one of the drive motors lc and ld and decelerating the other based on this steering signal, the guided vehicle 1 is caused to travel in the designated course direction.

By the way, in the magnetic tape guiding method described above, the guiding magnetic tape is split into two branch paths at a branch point, so that the tape width locally increases.

For this reason, the output of the magnetic sensor changes when the conveyance vehicle passes a branch point, which has a large effect on steering performance, especially when the vehicle passes a branch point while traveling straight.

Conventionally, the level of the magnetic sensor output is detected, and when the magnetic sensor output exceeds a predetermined level when passing a branch point, the output signal of the magnetic sensor and the shift signal are subtracted using an AND condition with the shift signal. A steering control method is known that prevents the influence that appears on the steering signal.

A circuit diagram of a conventional steering device for performing the above-mentioned steering control is shown in FIG. 2. In the figure, 7 is a dead band circuit, 8.9 is an amplifier, 10 is an inverting amplifier, 11 is an AND circuit, and is a level detection circuit, R1 to R5 are fixed resistors, VRI is a variable resistor, and E is a power supply.

Next, the operation of the steering control by the steering circuit 6 will be explained (ε
This will be explained together with the signal waveform diagram. Note that FIG. 4 shows a case where the transport vehicle 1 moves straight at a branch point where the traveling route branches into left and right branches (takes a course along the guiding magnetic tape 2a which branches to the right when viewed from the traveling direction). Here, when the conveyance vehicle 1 approaches a branching point of the travel route, it detects the shift mark 3 laid on the right side along the guiding magnetic tape 2a and shifts the shift switch 5.
R is turned on, and its operation signal is input to the steering circuit 6.

In addition, since the width of the guiding magnetic tape 2 changes at the branch point, the magnetic sensor 4 outputs a signal from the magnetic sensor 4 as shown in FIG. (+) increases and changes in a wave-like manner. On the other hand, the steering circuit 6
Then, when the output signal of the magnetic sensor 4 exceeds a preset detection level, a signal is output from the level detection circuit 12, and a shift signal is output from the AND circuit 11 under the AND condition with the operation signal of the shift switch 5R. . Further, this shift signal is radially inverted by the inverting amplifier lO, and is added to the output signal of the magnetic sensor 4 as a negative polarity signal.

As a result, the shift signal is subtracted so as to cancel the output of the magnetic sensor, and a steering signal obtained by combining both signals is outputted from the steering circuit 6 via the amplifier 8. Therefore, the conveyance vehicle 1 comes to travel straight along the guiding magnetic tape 2a on the right path.

In addition, when taking a course that curves to the left at the branch point shown in FIG. 4, a shift mark is laid on the left side along the guiding magnetic tape 2b. The left shift switch 5L operates. As a result, the shift signal is added to the output signal of the magnetic sensor as a signal of positive polarity, contrary to the case where the vehicle takes a course to the right as described above, and the guided vehicle 1 uses a steering signal obtained based on this to make a course to the left branch road. Shift and drive to take the position.

(1111 to be solved by the invention) By the way, in the conventional steering device shown in FIG. 2, the shift signal obtained from the AND circuit 11 of the steering circuit 6 detects the shift mark at the branch point and activates the shift switch. death,
In addition, since the output of the magnetic sensor is output after it has increased to a detection level or higher, there is a slight time delay from the time when the transport vehicle 1 approaches the turning point. Moreover, AND circuit 11
The shift signal output from is a step signal. For this reason, as shown in Figure 4, when taking a right-hand course at a fork and going straight, the output signal of the magnetic sensor is not canceled by the shift signal, and a complex waveform steering signal that changes sharply in the positive and negative directions is output. As a result, the conveyance vehicle cannot be steered smoothly, resulting in an unstable running posture in which the conveyance vehicle meanders from side to side.

The present invention has been made in view of the above-mentioned points, and provides a steering device for a magnetic g-guided automatic guided vehicle, which enables smooth steering control of the traveling of the guided vehicle when passing through a branch point in the traveling route. The purpose is to

[Means to solve the problem]

In order to solve the above problems, in the steering device of the present invention, based on an operation signal of a shift switch that is activated by detecting a shift mark installed at a branch point, a polarity shift corresponding to the shift direction is determined from the operation signal. A signal delay element is added to the shift signal generation circuit that generates the signal.

[Effect]

In the above, the shift signal generation circuit is a circuit that receives the operation signal of the shift switch as input and generates a shift signal with a polarity corresponding to the shift direction, and a capacitor as a signal delay element is inserted and connected in the circuit to shift the shift signal. This gives the signal a delay characteristic.

By inserting a signal delay element in the shift signal generation circuit in this way, when the guided vehicle approaches a branch point, the shift signal generated at the shift start point will not become a step signal due to the effect of the signal delay element. You will be able to stand up smoothly and smoothly. Similarly, at the shift end point, the shift signal falls gently. Therefore, by setting the installation range of the shift mark that specifies the shift start and end points and the time constant of the signal delay element appropriately in advance, a magnetic sensor whose shift signal waveform increases or decreases when passing a branch point can be used. As a result, the steering signal obtained by adding or subtracting the shift signal from the output signal of the magnetic sensor also has a waveform that does not change sharply in a stepwise manner but changes gently. As a result, the conveyance vehicle can smoothly pass through the branch point in a stable running posture without meandering.

〔Example〕

FIG. 1 is a circuit diagram of a steering device according to an embodiment of the present invention, FIG. 3 is a signal waveform diagram when passing a branch point according to FIG. 1, and FIG.
Identical parts corresponding to the figures are given the same reference numerals. First, in FIG. 1, the difference from the conventional circuit is the level detection circuit 12 in FIG. There is no AND circuit 11, and the shift signal generating circuit 13 is a circuit corresponding to the shift switch 5L, which is a variable resistor Vl? 1. Fixed resistance R2, R4
, l16. and a capacitor C1 as a delay element, and the circuit corresponding to the shift switch 5R is an inverting amplifier lO1 variable resistor VI12 fixed resistors R3, R5, R7.
, and a capacitor C2 as a delay element, and the output side of this shift signal generating circuit 13 is connected to an amplifier 8. Further, a signal attenuator 14 having a built-in resistor R8 or a capacitor C3 and a non-contact switch 15 are interposed and connected in series between the signal input terminals from the magnetic sensor 4. The non-contact switch 15 is turned on by the output signal of the OR circuit 16, and is connected to the OR circuit 16 so that the operation signal of the shift switch 5L5R is input thereto.

In the S rudder circuit 6 having such a configuration, the output of the magnetic sensor 4 is connected to the resistor R1, the dead band circuit 7. circuit 6 via amplifier 8
It is output from In addition, the operation signals of the shift switches SL and 5R, which are turned on by detecting a shift mark at a branch point of the traveling route, are converted into a shift signal with a polarity corresponding to the shift direction by the shift signal generation circuit described above, and are then sent to the amplifier 8. The signal is input to the magnetic sensor 4, and is summed there with the output signal of the magnetic sensor 4. At the same time, the non-contact switch 15 is turned on via the OR circuit 16, and the signal attenuation circuit 14 attenuates (reduces or delays) the output signal of the magnetic sensor 4.

On the other hand, the shift mark 3 on the floor side that indicates the traveling direction of the conveyance vehicle and the shift start and end point at a branch point on the travel route,
The cables are laid in the area shown in Figure 3. Note that, similarly to FIG. 4, FIG. 3 shows a case where the conveyance vehicle 1 moves straight along the right branch magnetic mark 2a at a branch point.

Next, the steering control operation by the circuit shown in FIG. 1 will be explained in conjunction with FIG. 3. When the Wi vehicle transport 1 approaches a branching point in the traveling route, the shift mark 3 is detected and the shift switch 5R is turned on, and the operating signal of the shift switch 5R is inverted in the polarity by the inverting amplifier 10, and the signal is applied to the variable resistor VR2. resistor R as a negative shift signal (-) adjusted by
3, and is input to the amplifier 8 via R7. In this case, the shift signal has a delayed characteristic due to the capacitor C2 as a delay element, and rises gently as shown in FIG. At the same time, the operation signal of the shift switch 5R enters the OR circuit 16 to turn on the non-contact switch 15. As a result, the output signal of the magnetic sensor 4 (solid line in FIG. 3) is
1 and the resistor R8 or capacitor C3 of the signal attenuator 14.
The voltage is divided by , and the voltage is attenuated as shown by the dotted line in FIG. Also, if the conveyance vehicle 1 passes a branch point and the shift mark 3 is no longer detected, the shift switch 5
R returns to off, but in this case as well, the shift signal falls gently due to the delay characteristic. As a result, the shift signal changes to the output waveform of the magnetic sensor in Figure 3 (
(represented by a dotted line), and by combining (subtracting) the output signal (+) of the magnetic sensor and the shift signal (-), the output of the magnetic sensor is almost canceled by the shift signal, and the steering signal reaches a branching point. It becomes almost zero in the passing region. As a result, the conveyance vehicle travels straight along the branched guiding magnetic tape 2a shown in FIG. 3 in a stable posture without almost meandering.

In addition, although the case of driving straight at the branch point shown in Fig. 3 has been described above, when taking the left course at the branch point, the shift mark placed on the left side of the branch guiding magnetic tape 2b is detected. The shift switch 5L is turned on, and the shift signal is sent to the amplifier 8 as a positive polarity signal (+), contrary to the above case.
and is added to the output signal (+) of the magnetic sensor 4. Thereby, the steering signal outputted from the steering circuit 6 controls the steering of the guided vehicle 1 so that it takes a left course and curves. Moreover, even in this case, the waveform of the shift signal does not have a step-like rise and fall, but increases and decreases smoothly, so the steering signal also has a gentle waveform, which allows the guided vehicle to change its course smoothly without meandering. Run.

Although the signal attenuator 14 in FIG. 1 is not necessarily required, by employing this signal attenuator 13,
It is advantageous to be able to slow down the sudden change in the magnetic sensor output that occurs when the guided vehicle passes through a branch point and incorporate it into the steering control system.

Further, although the above embodiment has been described with respect to passing through a branch point in the travel route, it goes without saying that similar steering control can be performed at a merging point as well.

[Effects of the Invention] Since the steering device of the present invention is configured as described above, it achieves the following effects.

In other words, by adding a signal delay element to the shift signal generation circuit and giving delay characteristics to the shift signal obtained by detecting shift marks at branch points in the travel route, the waveform of the shift signal changes in a step-like manner. The output waveform of the magnetic sensor becomes a near-image waveform, and this suppresses the steep change in the waveform of the steering signal obtained by summing the output signal of the magnetic sensor and the shift signal when passing a branch point. The steering control can be performed so that the conveyance vehicle smoothly travels through the branch points of the traveling route.

[Brief explanation of the drawing]

Figures 1 and 2 are circuit diagrams of an embodiment of the present invention and a conventional steering device, respectively, and Figures 3 and 4 are signal waveform diagrams when passing a branch point corresponding to Figures 1 and 2, respectively. , Figures 5 and 6 are a plan view and side view showing the configuration outline of the magnetically guided automatic guided vehicle, Figure 71E is a steering system diagram of the guided vehicle, and Figure 8 is the output of the magnetic sensor mounted on the guided vehicle. It is a characteristic diagram. In each figure, Ilvg, communication, 2: induction magnetic tape, 3: shift mark, 4: magnetic sensor, 5L, 5R: shift switch, 6
; Steering circuit, 13: Shift signal generation circuit, CI. C? Capacitor as a signal loss element. Figure 1 Figure 2 Figure 3 Figure 6

Claims (1)

[Claims] 1) A magnetic sensor and a shift switch on the transport vehicle detect the induction magnetic tape laid on the floor along the travel route of the transport vehicle and the shift mark placed at the branch point to indicate the direction of travel of the transport vehicle. This is a steering device for a magnetically guided automatic guided vehicle that performs steering control, and is configured to obtain a steering signal by adding a shift signal of a polarity corresponding to a shift direction obtained based on an operation signal of the shift switch to an output signal of a magnetic sensor. A steering device for a magnetically guided automatic guided vehicle, characterized in that a signal delay element is added to a shift signal generation circuit.