JPH0340841B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to the guidance of an unmanned trolley by automatically controlling the direction when the unmanned trolley moves along a guidance zone when the direction shifts. It is related to the device.

An unmanned trolley refers to a trolley that has a power source on it and is able to run automatically.Currently, devices that enable unmanned running are used in peripheral equipment of automated warehouses, goods transport equipment on production lines, and automated trolleys. It is widely used in transportation equipment in processing lines, etc., and its feature is that it does not have dedicated rails. The fact that it does not have dedicated rails is advantageous in that it can run on general factory corridors, allowing it to use space shared with forklifts and people, and that it is easy to change its running route.

[Prior Art] Conventionally, electromagnetic induction methods and optical guidance methods have been put into practical use as driving methods for unmanned trolleys.

In the electromagnetic induction method, as shown in Fig. 1, the running surface a
A pair of detectors d and d attached to the trolley c detect the induced magnetic field generated by passing a current through the guiding wire b embedded in the floor of the trolley c, and the running direction is controlled so that the detected strength is the same. This allows the trolley to run along the guide line. That is, the guide line b embedded in the running surface a
When a current is passed through, an induced magnetic field e is generated, and the system runs while detecting this induced magnetic field e with a pair of detectors d and d, and the center of the detectors d and
If it deviates in either direction, there will be a difference in the intensity detected by the detectors d and d, so by controlling the running direction of the cart so that the difference becomes zero, the cart can be moved along the guide line b. It is designed so that you can do it.

However, this guidance method has the following problems.

Since the guide wire b needs to be buried under the running road surface, the installation work is complicated, and it is also difficult to relocate or change the route, discover and repair breaks in the guide wire b, and so on.

The guide wire breaks due to subsidence of the running surface a, sudden vibration, etc.

Because the magnetic field is adversely affected by electrical conductors near the guide wire, there are many restrictions on the structure of the road surface. For example, on a reinforced concrete floor, etc., the reinforcing bars and guide wires need to be separated by a certain value or more, so it is necessary to make the distance between the running surface and the reinforcing bars larger than necessary.

Since there is a practical upper limit to the strength of the induced magnetic field,
The allowable deviation limit between the vehicle body and the guide wire is small.

Next, in the optical guidance method, a light reflector is installed on the floor of the running surface, the light emitted from the bogie is reflected by this light reflector, and the bogie is guided by detecting the relative position of the reflected light and the bogie. This is a method to do so.

That is, as shown in FIG.
light receiving section j that detects the reflected light.
This method detects the relative relationship between the truck c and the reflector i based on the position of the reflector i, and controls the running direction of the truck according to the amount of deviation. k is a running wheel.

In this method, as shown in Fig. 3, for example, when the light emitted from the light source h is detected at the left side of the light receiving part j, the cart c has shifted to the right side of the reflector i, so the amount of shift is A running direction correction command is given to the bogie c in accordance with this, and the trajectory is corrected so that the bogie c moves to the left side.

Other optical methods include a method in which the amount of reflection from a reflector is detected by a pair of light receiving sections, and the positions are controlled so that the amounts of reflection are the same.

However, these optical guidance methods have the following problems.

(1) Light reflection is likely to be inhibited by dust etc. adhering to the derivative.

(2) Light reflection is easily inhibited by damage to the dielectric surface.

(3) If the running surface is uneven, it is difficult to install reflectors and even those that are installed are likely to peel off.

As mentioned above, both the conventional electromagnetic induction method and the optical induction method have many problems. The installation method is complicated.

Therefore, recently, as shown in FIGS. 4 to 6, a magnetic guiding band 1 extending in the direction in which the unmanned trolley is intended to run has been laid on the running surface 2. It is equipped with left and right traveling drive wheels 4 driven by independent traveling drive motors 5, and equipped with left and right driven wheels 6 at the front and rear. It has a configuration in which magnetic detection sensors 7 and 7' are attached, and further includes a calculation device connected to the magnetic detection sensors 7 and 7', and a rotation of the travel drive motor 5 based on the amount of directional deviation calculated by the calculation device. An unmanned trolley guidance system has been devised in which a traveling drive control device that issues commands to perform control, other batteries, etc. are mounted on the trolley 3, and the unmanned trolley can travel along the guidance zone 1 while correcting direction. .

In such a device, a magnetic detection sensor 7,
7' is composed of a large number of magnetic detection elements 8, and each magnetic detection element 8 is located at a height position that responds to the strength of the magnetic field 9 of the induction band 1 having a constant magnetic force, and on the left and right sides of the trolley 3. arranged at a predetermined pitch in the direction,
Each magnetic detection element 8 is connected to a computing device and displayed as an address within the computing device, and when any magnetic detection element 8 detects magnetism, an address is displayed corresponding to that element 8. At the same time, the distance between the displayed address and the reference position is calculated as the amount of deviation by the arithmetic unit, and a control command is sent from the travel drive control device to the travel drive motor 5 so that the amount of difference becomes zero. , left and right drive wheels 4
The direction of the truck 3 is controlled by controlling the rotation of the truck.

However, such recently devised devices are expensive because (i) the magnetic detection sensor requires a large number of magnetic detection elements to be lined up;

(ii) Since the gap between the magnetic detection sensor and the induction band, which is a magnet, can only be about 50 mm at most, there is a problem with sensitivity.

(iii) Since the output of the magnetic detection sensor is the ON-OFF signal of each magnetic detection element, the control method of the DC motor (analog method) which is the induction control operation end
In order to correspond to this, signal conversion (D/A conversion) is required, which complicates the circuit.

It had the following problems.

[Object of the Invention] In view of the above-mentioned circumstances, an object of the present invention is to provide a guidance device for an unmanned bogie that is capable of reducing costs and improving guidance performance.

[Structure of the Invention] The guidance device for an unmanned trolley of the present invention has an induction band made of a magnetic material installed on a running surface along the running direction of the trolley, and a sensing coil made of a ferromagnetic material with a rough center and a rough guide band at both ends. Attaching a guide band sensor formed in a dense manner in the width direction of the trolley,
The vehicle is equipped with a detector that detects displacement of the truck based on the signal from the guide band sensor, and has a control device that sends a control signal to the drive system of the truck based on the output from the detector.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

As shown in FIGS. 7 to 10, a guide band 10, which is a magnetic body extending in the direction in which the unmanned trolley is intended to travel, is laid on the running surface 2, while the front and rear ends of the lower surface of the unmanned trolley 3 are is equipped with an inductive band sensor 12, 12' using a sensing coil 11 whose conductor is a ferromagnetic material such as permalloy, and a detector 1 connected to the inductive sensor 12, 12'.
3, a steering control device 14 which calculates the amount of deviation of the trolley 3 based on the value calculated by the detector 13 and issues a command to control the rotation of the traveling drive motor 5 in accordance with the amount of deviation, and other batteries. etc. are mounted on a trolley 3, and the vehicle is constructed so that it can run unmanned along a guide zone 10 while correcting the direction. 15
is a DC motor drive unit.

Further, in the detector 13, OS is a high frequency oscillator connected to the center of the sensing coil 11 in order to send an excitation current through it, _D1 is a diode connected to one end of the sensing coil 11, and D2 _is
is a diode similarly connected to the other end, and 16 is a bridge circuit. The sensing coil 11 is
It is bent in a zigzag pattern so that it is roughly folded in the center and densely folded in both ends.

Now, based on the state in which the center of the induction band sensors 12, 12', that is, the center of the sensing coil 11 coincides with the center of the induction band 10, the bridge circuit 16 is balanced and the output is zero. The bogie 3 is run with the center of the guide band sensors 12, 12' aligned with the center of the guide band 10.

If the trolley 3 shifts left or right while it is running, it will be affected by the magnetism of the induction band 10, and the current in the conductor on the side affected by the sensing coil 11 will increase, causing the bridge circuit 16 to become unbalanced, resulting in an output value. changes. The sensing coil 11 is rough in the center and becomes denser as it approaches both ends.
As shown in FIG. 1, as the center of the sensing coil 11 and the center of the inductor 10 shift, the output value also changes greatly. Therefore, a control command that makes the amount of deviation zero is sent from the steering control device 14 to the travel drive motor 5 via the drive unit 15, and the rotation of the left and right drive wheels 4 is controlled to control the direction of the bogie 3. be exposed. A signal is fed back from the travel drive motor 5 to the steering control device 14, and direction control is performed until the amount of deviation becomes zero.
The truck 3 is automatically guided so that the center of the inductive sensors 12, 12' of the truck 3 coincides with the center of the guide band 10.

Note that the course can be changed by adding a switching circuit that changes the direction of the diodes D ₁ and D ₂ of the detector 13 to change the polarity depending on the polarity (N, S) of the inductive band 10.

In the above, as the induction band 10, it is sufficient to simply attach a thin magnetic tape of about 0.8 mm to the floor surface, and no floor processing work is required.
The width is narrower than the guide band 11 shown in the figure. or,
The inductive sensors 12, 12' can be made extremely thin by simply bending a ferromagnetic conductor of 1 mm or less and attaching it to a non-magnetic plate such as acrylic or plastic. Therefore, sensors for different purposes such as for going straight, for left turns, and for right turns can be made all at once. Furthermore, since the inductive sensors 12 and 12' are made of ferromagnetic conductors, sensing can be performed even by minute changes in the angle formed between the direction of the magnetic field of the inductive band 10 and the direction of the current in the inductive sensors 12 and 12'. Since the resistance value of the coil 11 changes sharply (when a high frequency current is used as in the present invention, the current is concentrated on the surface of the sensing coil 11 due to the skin effect, so the resistance value changes even more sharply). The sensitivity is high, and the gap between the guide band 10 and the guide band 10 can be made larger (approximately twice as large) as compared to the systems shown in FIGS. 4 to 6.

In the above embodiment, the sensing coil 11 is formed by bending in a zigzag shape, but for example, the sensing coil 11 may be bent into a comb shape as shown in FIG. may be changed.

[Effects of the Invention] As explained above, according to the guidance device for an unmanned trolley of the present invention, () it is sufficient to simply attach a narrow material such as magnetic tape to the floor as the guidance band; No machining work is required, which is advantageous in terms of cost.

() Both the sensor and detector have a simple structure, are inexpensive and highly reliable.

() The output value of the induction band sensor is weak in the center,
The force increases at both ends, so when the misalignment of the bogie is small, the control effect that tries to return the misalignment becomes weak, and when the misalignment of the bogie becomes large, the control effect that tries to return the misalignment becomes stronger. It can be stably guided.

() Since the sensor sensitivity is high, a large gap can be created between the sensor and the induction band.

It can produce excellent effects such as

[Brief explanation of the drawing]

Figures 1 to 3 are schematic diagrams of the conventional system, Figure 4 is a plan view of a recently devised device, and Figure 5 is the fourth
6 is a front view showing the combination of the magnetic sensor and the induction band, FIG. 7 is a plan view of the device of the present invention, FIG. 8 is a side view of FIG. A block diagram of the device of the invention, FIG. 10 is an explanatory diagram of the inductive band sensor and its control system, FIG. 11 is a diagram showing the relationship between the output and displacement of the detector, and FIGS. 12 and 13 are the inductive band sensor, respectively. It is another example figure of. 3 is a bogie, 4 is a driving wheel, 10 is a guide band, 1
1 is a sensing coil, 12 and 12' are inductive sensors, 13 is a detector, 14 is a steering control device, and 16 is a bridge circuit.

Claims (1)

[Claims] 1 An inductive band sensor is made by attaching an inductive band made of a magnetic material on the running surface along the running direction of the bogie, and forming a sensing coil with a ferromagnetic material as a conductor so that it is coarse in the center and dense at both ends. The present invention is characterized by having a detector installed in the width direction of the bogie to detect displacement of the bogie based on a signal from a guide band sensor, and a control device that sends a control signal to the drive system of the bogie based on the output from the detector. A guidance device for unmanned trolleys.