KR920009051B1 - A vehicle guidance and control system - Google Patents

Abstract

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Description

Vehicle guide

1 is a schematic plan view of a vehicle guide control apparatus according to the present invention.

2 is a vehicle.

3 is a reflector.

4 is a partial view of a laser beam scanning head mounted on a vehicle.

5 is a circuit diagram installed in a laser beam scanning head.

* Explanation of symbols for the main parts of the drawings

1: dashed line 2, 3: truck

4: base station 5: material area

6: working position 7: storage area

8: reflector pin 10: loading surface

11 ridge 12 rotating scanner head

13 arrow 14 narrow fan-shape laser beam

21: gallium arseride diode laser

23: optical device 24, 25: mirror

26: small mirror 27: light sensor

28: cylindrical stove 29: inclined mirror surface

30, 31: wide linear laser beam 32: base diode

34, 35: bearing 36: small motor

38, 39: balanced beam 40: interface device

41: oscillator 42: narrow-band surface

43: comparison of the above 44 44: range converter

The present invention relates to a vehicle control guide device that accurately moves one or more vehicles having their own power and coordination within a predetermined area of a space.

Since the vehicles can move freely to any position in the present invention, the device of the present invention is a device in which vehicles can be guided to a highly accurate position along such a non-determined route.

According to a first aspect of the present invention, a vehicle guide control apparatus includes a plurality of reflectors spaced apart from a vehicle having power means, adjustment means, and means for transmitting a directional laser beam scanned in a predetermined direction. Each reflector installed to be able to block the laser beam is combined with an optical code that recognizes the reflector. The vehicle guide control apparatus also includes means for using light reflected back to the vehicle by at least two reflectors to control the movement and direction of the vehicle.

According to a second aspect of the present invention, a plurality of vehicles controllable in the vehicle guide control apparatus include individually controllable power means and steering means and transmission means of a directional laser beam continuously scanned in the same direction, and the base station is provided with An optical code for recognizing the reflector is coupled to each of a plurality of mutually spaced reflectors installed to allocate the planetary ground of the vehicles and to block the continuous scanning laser beam. The present vehicle guide control device also includes means for utilizing light reflected back to the vehicle by at least two reflectors for controlling the vehicles to move to their respective destinations.

Thus, the laser beam can be scanned continuously in the clockwise or counterclockwise direction.

The characteristics of each reflector and the arrangement of the means for recognizing the reflector are preferably dependent on the scanning direction (ie clockwise or counterclockwise) of the laser beam.

The present reflector is preferably composed of a stripe arrangement arranged transverse to the scanning direction, and the stripe has a reflective characteristic different from its background (i.e., a secondary stripe array staggered with it). In this way, the stripe constitutes an optical pattern of binary codes that distinguish the reflector from other objects. At least one of the stripes determines the exact desired location within the device and at the same time the light reflected back to the vehicle is used by the vehicle to determine the angular position of the vehicle relative to the location of the stripe.

The shape of the directional laser beam is extremely narrow in the azimuth direction and fan-shape in the vertical direction so that the reflector can reach the reflector even if the heights of the reflectors are different from each other and the platform for scanning the laser beam is not exactly horizontal.

If all the reflectors are installed at the correct height, you can use a pencil laser in the correct horizontal direction, and the result is very effective.

The means for transmitting a directional laser beam consists of a device for projecting on a tilting mirror on which a pencil-like beam rotates about a vertical axis. A lens is placed directly below the mirror surface to convert the pencil beam into a linear beam.

It will be described below in detail with reference to the drawings.

FIG. 1 shows that two vehicles 2, 3 are guided under the control of the base station 4 in the area shown by the broken line. The vehicle 2, 3 is used to transport raw materials between the work area 5 and the work position 6 during work.

The material area contains the raw materials to be processed at the working location and the finished product is transported to the storage area 7 by one vehicle.

The base station 4 assigns destinations to each truck 2, 3 via a convenient form of communication link, an infrared transmitter and an infrared detector mounted on the ceiling of the area shown by a short range wireless communication link or broken line 1. An optical communication device using is an example of this communication link. In the latter case, each vehicle is equipped with an infrared sensor and an infrared transmitter which cooperatively operate with the communication link. Once assigned to a particular destination, each vehicle automatically operates to a highly accurate location in accordance with the transmitted instructions and depending on the reflector substrate 8 installed around the sea area of the vehicle. Each reflecting substrate contains a unique code that indicates its recognition and exact location, which is shown in detail in FIG.

Each vehicle scans on a reflecting substrate in its field of view with a rotating scanning laser beam. The reflecting substrate is made of retro-reflective material, and reflects the original light incident on it with a narrow beam in the same direction as the incident direction.

Thus, each vehicle can accurately determine the position of at least two reflectors relative to the position of the vehicle itself, using trigonometry in the dashed line (1), ie restraint area (5), work position (6) and storage area (7). It is possible to determine the position of the vehicle itself with respect to any position within).

As the vehicle travels along a path leading the vehicle to the required destination, the vehicle continuously monitors its position. By continuously transmitting the vehicle's position to the base station, the base station can detect the position of the entire truck and control the two trucks from colliding. In the material zone 5, the work position 6 and the complementary zone 7 special precise control is required, so additional reflectors are provided around these positions as in FIG.

In practice, the material and storage areas are larger than shown and complex in shape. For example, these areas consist of many compartments divided into several parts by narrow passageways through which trucks can operate. This would require an additional reflector board that would allow the truck to always communicate between at least two compartments in the compartment.

2 is a schematic diagram of a small vehicle, which includes a loading surface 10 and a ridge 11, which supports the rotating scanner head 12. As shown in FIG. As the scanner head rotates, a very narrow linear laser beam 14 is transmitted. However, at this time, narrower and parallel pencil beams are preferred than linear beams. The linear beam is considerably vertical spread (which is determined by the linear vertex angle) so that at least part of the laser beam 14 can be incident on the reflecting substrate 8 regardless of the height of the reflecting substrate.

As described above, the main reflective substrate 8 is arranged with stripes and arrays in a vertical arrangement.

Assuming that the laser beam rotates clockwise as in the direction of arrow 13 in FIG. 2, the beam is continuously scanned from left to right of the reflecting substrate. As a result, the reflecting substrate 8 carries a width modulation beam having a pattern that changes with time in correspondence with the light portion (the reflecting portion) and the dark portion (the absorbing portion) of the reflecting substrate. The conveyed signal is received by a detector installed in the scanning head, and the received information allows the vehicle to determine the exact relative position with respect to the reflecting substrate 8 and by using the conveying beam reflected from two or more reflecting substrates. By correcting the vehicle's route, any positional errors can be compensated.

3 shows the reflective substrate in more detail, wherein the reflective substrate includes a reflective stripe which is spaced apart by non-reflective regions as hatched portions in the figure. The widths of the reflected and non-reflective stripes determine the characteristics of the code signal obtained here. In FIG. 3, a narrow anti-reflective stripe arranged after a wide reflective stripe is represented by '1', and conversely, when a wide anti-reflective stripe is arranged after a narrow reflective stripe, it is represented by '0'.

Assuming that the reflecting substrate 8 is scanned from the sin side to the right as described above, the first few stripes serve to indicate that it must be a reflecting substrate. It is important to distinguish the reflecting substrate from other reflectors in the field of view that produce a reflecting pattern that is confusingly similar to the pattern of the reflecting substrate, that is, an object in which many wires are arranged vertically, such as a metal grid. When the initial patterns of '1' and '0' that recognize the reflecting substrate are found, they are followed by a unique code that distinguishes a particular reflecting substrate from other surrounding reflecting substrates.

Any stripe can be selected as the position member, but in this embodiment the final vertical stripe indicates the position of the reflecting substrate end with a very high degree of constancy, usually within 1 cm, as the position stripe. In devices requiring very high positional accuracy, the stripe has a significant width so that the boundary end of the stripe is used to indicate the position of the reflecting substrate. Thus, as soon as the rotating scanning head receives the signal reflected from the present end strip, it is possible to determine the angular position of the shade relative to the angular position of the reflecting substrate.

For convenience along the corridor, two reflectors can be placed in a specific reflecting position that can be easily observed by a truck approaching from both directions of the corridor. In this case, the stripe at the end where the two reflecting substrates come into contact serves to determine a common position with respect to the orientation of the truck itself.

Accurate optical encoders keep track of the angular position of the rotating scanner head 12 relative to the angular position of the vehicle. This kind of angular orientation received from at least two reflecting substrates can accurately determine the absolute position of the vehicle. The angular offset of the vehicle from the reflecting substrate is used to indicate the actual direction of the vehicle so that it can proceed to the destination required by the vehicle.

4 shows a very detailed view of the scanning head 12, in which the laser 21 generates a narrow beam of high intensity coherent light, which is approximately 5 mm wide parallel pencils by the optics 23. FIG. Is enlarged with a beam. The laser is a conventional gas-filled or semiconductor light source such as a gallium arsenide laser diode composed of a mixture of helium or neon. The narrow pencil beam emitted from the optics 23 is reflected upward from the mirror 24 toward the mirror 25 which is fixed to the vehicle. The reflected beam is then reflected at the small mirror 26 attached to the center of the annular area constituting the large-area optical sensor 27 to reach the reflective surface of the inclined mirror 29 in the case of the cylindrical lens 28. do. The lens in combination with the mirror generates a linear beam with a very large angle, as defined by lines 30 and 31. The vertex angle of this linear line is about 40 degrees normally.

This mirror 29 having a flat surface is supported by a rotating frame 32 which is fixed to a base diode 33 supported by bearings 34 and 35 and driven by a small motor 36. This causes the laser beam reflected from the mirror and thus the mirror to rotate at about three revolutions per second.

The light reflected by the reflecting substrate is conveyed by the parallel beams indicated by the lines 38 and 39 to be incident on the surface 29 of the inclined mirror and reach the large-area optical sensor 27. By using the retroreflective stripe on the target plate, the light incident thereon is conveyed to the sensor 27 at a high rate where the retroreflective material conveys the incident light along the original path irrespective of the angle of incidence.

Typically, the sensor 27 is composed of a photodiode, and an interference filter may be installed directly above the sensor 27 to reduce the ambient light effect.

The information is extracted in an electrical form through the interface device 40 and input to the analysis circuit to utilize according to the sales. When a gallium arsenide diode laser is used to generate the beam, the light output is typically pulsed at a predetermined high frequency greater than 1 MHz, and a band filter tuned at the same frequency in the output path of the sensor 27 is a reliable counter to the interference of ambient light. Identify. The truck distance from the reflecting substrate is directly obtained by modulating the beam in an amplitude pulsed manner. Although the transmission time of the pulse reflected back to the sensor is simply measured, it is desirable to compare the phase of the modulated reflected wave with that of the emitted beam.

5 is a diagram of such a device, in which an oscillator 41 operating at about 100 MHz is used to operate the gallium arsenide diode laser 21 in amplitude modulation. The output of the sensor 27 is input to the narrowband filter 42 tuned to the frequency of the oscillator 41 via the interface device 40. The filtered signal is input to the phase comparator 43 and compared with the output of the oscillator. The phase difference (i.e. change in phase) is directly related to the distance from the reflecting substrate to the truck and is converted into a distance measurement at the converter 44. Precise positioning is required when using one reflector because the approximate position of the truck can be obtained by monitoring the movement of the truck from the position relative to the two reflectors. The use of high optical frequency modulation with an effective short wavelength can make the calculation position of the truck clear.

Claims (8)

In a vehicle guide control apparatus, a vehicle having a power means, a steering means, and a means for transmitting a directional laser beam scanned in a predetermined direction is combined with an optical code for identifying a reflector and spaced apart from each other to block the laser beam. And means for using a plurality of reflectors to be installed and light reflected back to the vehicle by at least two reflectors to control the movement and direction of the vehicle. A vehicle guided control apparatus comprising: a plurality of controllable vehicles having individually controllable power means and steering means and means for transmitting a continuous laser beam that is continuously scanned in the same direction, and allocating a destination for the vehicle A plurality of reflectors coupled to the base station, an optical code identifying the reflector and spaced apart from each other to block the continuous scanning laser beam, and from at least two reflectors to the vehicle to allow the vehicle to move to each destination. Vehicle guide control apparatus comprising a means for using the reflected light. 3. The vehicle guide control apparatus according to claim 2, wherein the characteristics of each reflector and the arrangement of the means for identifying the reflector depend on the night direction in which the laser beam is scanned. 4. The vehicle guided control according to claim 2 or 3, wherein the reflector comprises an array of stripes arranged in a direction crossing the scanning direction, the stripe having a predetermined reflection characteristic different from its background. Device. 5. The vehicle guide of claim 4, wherein at least one of the stripes accurately determines the position of the device, and at the same time light reflected back towards the vehicle is used by the vehicle to determine the position of the vehicle itself relative to the stripe. Control unit. 6. The vehicle guide control apparatus according to claim 5, wherein the means for transmitting the directional laser beam is constituted by an apparatus for raising the pencil beam toward the inclined mirror rotating about the vertical side. 7. The vehicle guide control apparatus according to claim 6, wherein the transmitted laser beam is modulated to directly determine a distance of a reflecting reflector. 8. The vehicle guide control apparatus according to claim 7, wherein means for determining a phase of a carrier wave for the transmitted beam is provided to indicate the distance.

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