JPH0363084B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an optical guidance device for automatically guiding, positioning, and stopping a traveling moving object such as an automatic guided vehicle or a mobile robot using a light beam.

[Prior art]

Traditionally, for example, the ``5th Vehicle Automation Symposium'' was held at the Japan Automatic Control Association on January 26 and 27, 1982, and the ``5th Vehicle Automation Symposium'' was held on January 25 and 26, 1982. As announced at the 6th Vehicle Automation Symposium, it is generally known that automated guided vehicles can be automatically guided using a light beam such as a laser beam.

16a and 16b show conventional devices of this type, FIG. 17 is a detailed view of the device shown in FIG. 16b, and FIG. 18 is a detailed view of the light receiving device. For example, as shown in FIG. 18, the automatic guided vehicle 2 has a light receiving device in which a large number of photoelectric sensors 2a such as solar cells are arranged laterally in an array;
- A laser light source such as a Ne oscillator tube, 4 is a swinging mirror driven by a beam scanner 5, 6 is a narrow straight beam irradiated from the laser light source 3 to the light receiving device 2, 6a and 6b are swinging mirrors 4 in a fan shape 7 is the maximum swing width of the light beam swept at an angle α, and 7 is the traveling course of the automatic guided vehicle 1. Further, 8 is the central axis of the light receiving device 2, and 9 is the central axis of the vehicle body.

Next, the operation will be explained. In the conventional device shown in FIG. 16a, a light beam emitted from a laser light source 3 is irradiated onto a light receiving device 2 as a narrow straight beam 6. Further, in the conventional device shown in FIG.
The light is swept in a fan-shape at a constant period along the scheduled travel course 7, and is received by the light receiving device 2. In any of the conventional devices, for example, as shown in FIG. 18, the amount of lateral deviation w of the light receiving device 2 with respect to the planned travel course 7 can be detected based on the position of the photoelectric sensor 2a that receives the light beam. Therefore, in the automatic guided vehicle 1, the projected beam is located at the center of the photoelectric sensor 2a.
By steering the vehicle according to the amount of lateral deviation w so that the vehicle can receive light, the vehicle can travel along the planned travel course 7.

By the way, since the conventional device shown in FIG. 16a uses a narrow straight beam, the light intensity is strong, the S/N ratio of the optical signal is good, and signal processing is easy. The height dimension of the light-receiving surface must be large enough to cope with vibrations of the vehicle body, sinking of the vehicle body due to load, etc., and the sensor and optical system of the light-receiving device become expensive. Furthermore, since the light intensity is strong, there is a serious problem of danger to human eyes, and there is also a problem that there are restrictions on the installation location.

On the other hand, the conventional device shown in FIG. 16b sweeps the light beam fan-shaped in a vertical plane, so there is no limit to the height of the light receiving surface, but as the distance from the light projecting device increases, The disadvantage is that the ratio of the light reception time to the sweep period decreases, and the S/N ratio of the optical signal decreases significantly. For this reason, a light receiving sensor that responds quickly is required.

In addition, in any of the above conventional devices, since the amount of lateral deviation with respect to the central axis of the photoelectric sensor that receives light is detected, the attitude angle shown in FIG. 18, for example, cannot be calculated unless the vehicle has traveled a certain distance straight. In addition, other means such as magnetic, optical, or mechanical were required to position the automatic guided vehicle to the target point.

[Summary of the invention]

This invention was made with the aim of eliminating such drawbacks, and it improves the shape or sweep method of the light beam, as well as the structure of the light receiving device, thereby simultaneously detecting the amount of lateral deviation and the attitude angle, and quickly orbiting. The light beam of the traveling movable body enables corrective steering, and a target position detection device is installed on the traveling movable body to detect the stop position of the traveling movable body using the above-mentioned light beam, thereby obtaining accurate positioning and stopping. This paper proposes a guidance device.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 15.

FIG. 1 is an overall configuration diagram of a light guiding device according to the present invention, in which 1 is an automatic guided vehicle, 3 is a laser light source, 6c and 6d are the upper and lower ends of the vertically long and horizontally narrow beams, and 20 is the automatic guided vehicle 1. Detection device 40, which is installed above and includes a light receiving device that simultaneously detects the amount of lateral deviation and attitude angle of the traveling movable body with respect to the light beam, and a target position detection device that detects the stop position of the traveling movable body.
is an optical system that forms a vertically long, horizontally narrow, oblate and parallel light beam.

By using a vertically elongated beam, there is no restriction in the height direction of the light-receiving surface, and furthermore, the laser light source 3
Since the light reception time is the same even at a point far away from the center, the S/N ratio of the optical signal decreases very little. Also, since the light beam is expanded vertically,
The intensity of light that enters the human eye is also reduced and is safe. Moreover, since the flattened light beam has a horizontally narrow cross-sectional shape, there is an advantage that accuracy does not decrease when detecting the amount of lateral deviation and attitude angle of the automatic guided vehicle 1.

FIG. 2 shows an embodiment of a light projecting device according to the present invention. In the figure, 42 is a beam expander;
3 represents a cylindrical concave lens, 44 represents a cylindrical convex lens, and 45 represents the cross-sectional shape of the flattened light beam. The lens 43 functions to expand the parallel beam with a thin circular cross-section from the beam expander 42 into a fan shape only on the vertical plane, and the lens 44 functions to return this fan-shaped light to parallel rays only on the vertical plane, and both of them function to expand the parallel beam with a thin circular cross-sectional shape into a fan shape on the vertical plane. maintains a width equal to the incident beam diameter. Also, the beam expander 42 converts the beam from the laser light source 3 into a circular parallel beam of a required diameter.

The above optical system provides substantially uniform light intensity over the entire area of the flat cross section. Note that as another means, substantially the same effect can be obtained by sweeping the flat cross-sectional area up and down with a circular parallel beam.

Figures 3a to 3d are schematic configuration examples thereof, and 4
6 is a polygonal rotating mirror, 47 is a collimator lens, 48 is a swinging mirror, 49a and 49b are parallel mirrors or parallel prisms that swing at the same angle as a pair, 60 is a mirror that moves vertically up and down, and 61 is a cross section of the optical path. It represents.

Next, prior to explaining the light receiving device, the principle of detecting the amount of lateral deviation and attitude angle will be explained.

Figures 4a and 4b show the principle of a linear position sensor, which is achieved by applying a bias voltage V _B to a flat photoconductive element and adding an operational amplifier circuit as shown in Figure 4a. As a result, a voltage signal proportional to the position irradiated with the light beam is obtained as shown in FIG. 4b.

FIG. 5a is a plan view of the basic part of the light receiving device according to the present invention, and FIG. 5b is a front view of the same. In the figure, S ₁ and S ₂ are linear position sensors, which are installed in parallel at a known interval l. Further, as shown in FIG. 5B, these are installed at different heights, so that vertically long and horizontally narrow light beams can be received simultaneously without interference.

In FIG. 5a, when a light beam is irradiated at a certain angle with respect to the central axis of linear position sensors S ₁ and S ₂ installed in parallel, each sensor S ₁ ,
The positions d ₁ and d ₂ of the light beam can be detected from the output of the operational amplifier added to S ₂ . Here, since the distance l between each sensor S ₁ and S ₂ is known, the amount of deviation y between the sensor center O and the light beam axis and the angle φ between the sensor center axis and the light beam axis are determined by the sensor in FIG. First, consider a coordinate system in which the x-axis is the axis and the y-axis is the axis passing through the center O of the sensors S ₁ and S ₂ and perpendicular thereto,
Then, the point where the light beam is received by sensors S ₁ and S ₂ is
Assuming P ₁ and P ₂ , the coordinates of this point are P ₁ = (x ₁ , y ₁ ) = (-l/2, d ₁ ) P ₂ = (x ₂ , y ₂ ) = (-l/2, d ₂ ) Therefore, the coordinates of the midpoint M are M = (x ₁ + x ₂ /2, y ₁ + y ₂ /2) = (O, d ₁ + d ₂ /2
) Therefore, y=d ₁ + d ₂ /2 ...(1) Also, the slope tanφ is calculated from the mathematical formula: tanφ=y ₂ −y ₁ /x ₂ −x ₁ =d ₂ −d ₁ /l Therefore, φ=tan ^-1 d ₂ −d ₁ /l ...(2) The above equation (2) is φ=tan ^-1 d ₂ −d ₁ /l, and the result of φ is opposite in sign to the above equation, but the I don't think there is any particular problem in processing, since all you have to do is decide which meaning is considered positive or negative.

Next, we will discuss the case where a light receiving device using this principle is mounted on an automatic guided vehicle.

In FIG. 6, 10 is a light receiving device mounted on the automatic guided vehicle 1, and 30 is a light projecting device that generates the flat beam described above. Also, A ₁ − _{A 2} is the optical beam axis,
B ₁ -B ₂ and C ₁ -C ₂ are the vehicle body center axes of the automatic guided vehicle 1.

In FIG. 6, since the light receiving device 10 is mounted so as to coincide with the center axis of the vehicle body, the attitude angle and the amount of lateral deviation y of the vehicle body can be immediately determined from the above equations (1) and (2). However, as y becomes larger, the dimensions of the light receiving device 10 and the linear position sensors S ₁ and S ₂ also need to be increased.

FIG. 7 shows an example of a light receiving device improved in this respect, and the same reference numerals indicate the same components.

In this case, the light receiving device 10 is connected to the vehicle body center axis C ₁ -C ₂
The light receiving device 10 itself is mounted so as to be movable thereon, and furthermore, the light receiving device 10 itself can be rotated. And the above movable and rotatable mechanism has a light beam axis A ₁ −
Follow-up control is performed so that A ₂ coincides with the central axis of the light receiving device 10.

According to such a method, an increase in y can be handled using a small light receiving device and a linear position sensor.

FIG. 8 is an explanatory diagram for calculating the attitude angle and the amount of lateral deviation y using the light receiving device mounted on the automatic guided vehicle. In order to simplify the explanation, FIG. 8 shows a case where the rotatable axis of the light receiving device and the optical beam axis coincide with the center of the linear position sensor _S1 . In the figure, O is the center of the vehicle body, θ is the turning angle of the light receiving device, w is the amount of lateral movement of the light receiving device, d is the amount of deviation detected by the linear position sensor _S2 , and θ, w, and d are each detected by the measurement control device. Suppose it is possible. At this time, it can be calculated as =π/2-θ+tan ^-1 d/l...(3) y=w cos...(4). Note that it goes without saying that even in the case where the rotatable axis of the light receiving device and the optical beam axis do not coincide with the center of the linear position sensor _S1 , the calculation can be performed using roughly the same method.

FIG. 9 shows a schematic structure of the main part of the light receiving device, in which FIG. 9A is a plan view, FIG. 9B is a front view (partially sectional view), and FIG. 9C is a side view. In the figure, 11 is a dark box, 12 is a rotation axis, 13 is a hood that protects from disturbance light, and 14 is a filter that transmits the wavelength of the projected light beam.

Figure 10 is for explaining the outline of the mechanism for turning and moving the light receiving device on the carrier vehicle.
Reference numeral 5 denotes a horizontal drive mechanism that can shift the light receiving device along the sensor movement axis C ₁ -C ₂ and also detect the amount of deviation w from the reference axis. This is a light receiving device turning mechanism that can also detect the turning angle θ with respect to the vehicle body reference direction.

Next, using the flattened light beam according to the present invention,
For positioning the automatic guided vehicle 1 at the target position,
The target position detection device will be explained. FIG. 11 is an explanatory diagram of its principle, with reference numeral 50 a target station such as transfer equipment, 51 a small reflector attached to a positioning target position, and 52 an automatic guided vehicle 1.
A branching mirror 53 is a photoelectric element such as a linear position sensor, which is built into a target position detecting device mounted on the target position detecting device.

In the figure, the automatic guided vehicle 1 is traveling guided by a flat light beam on the main road, and projects a part of the flat light beam in a lateral direction perpendicular to the main road by means of a branching mirror 52. Since the approximate position of the destination station can be known in advance from the distance traveled, etc., the user pays attention to the optical signal from the photoelectric element 53 while traveling at a low speed near the destination station. When the projected light from the branching mirror 52 hits the small reflecting mirror 51 of the station, the photoelectric element 53 receives the reflected light, so that the target position can be accurately detected and positioned and stopped.

FIG. 12 schematically shows the structure of the target position detection device, in which the aforementioned branching mirror 52 and a photoelectric element 53a such as a linear position sensor are housed in a device housing 54. The main flattened light beam enters through the intake window 55 and passes through the branching mirror 52.
The beam is projected through the branch beam window 56 toward the small reflecting mirror 51a at the target position. The reflected light from 51a is received by a photoelectric element 53a provided in the branched beam window 56, and the position of the automatic guided vehicle 1 relative to the target position can be accurately determined by the light receiving position on the photoelectric element 53a.

FIG. 13 shows that the branching mirror 52 is rotatable,
Furthermore, by installing another photoelectric element 53b such as a linear position sensor at a position symmetrical to the photoelectric element 53a, it is possible to detect the small reflecting mirror 51b at the target position on the opposite side of the main road. Furthermore, by rotating the branching mirror 52 by 180 degrees or using a double-sided mirror, it is possible to cope with the case where the traveling direction of the automatic guided vehicle is reversed and the direction of the flat light beam is reversed.

FIG. 14 shows a specific example of the target position detection device, in which FIG. 14a is a plan view (partially sectional view), FIG. 14b is a side view, and FIG. In the figure, 1
3 is a hood, 14 is a filter, and 57 is a rotating drive mechanism for a branching mirror.

FIG. 15 shows an example of an unmanned transport system using a light guidance method to which a light projecting device, a light receiving device, and a target position detecting device according to the present invention are applied.
15 is an automatic guided vehicle, 15 is a horizontal drive mechanism, 16 is a light receiving device rotation mechanism, 58 is a light receiving device for detecting the position and attitude of the vehicle body similar to that explained in FIG. 10, and 59 is the same as explained in FIG. 14. target position detection device, 5
Reference numeral 1 indicates a target position reflector provided on a station 50 or the like, and 45 indicates a cross-sectional shape of a flat light beam on the main path.

In addition, in the above example, in order to clarify the configuration,
Although the light receiving device 58 and the target position detecting device 59 are independent devices and are shown as a combination thereof, by adding a branching mirror 57 similar to that built in the target position detecting device 59 to the light receiving device 58, the above 2. Needless to say, it is possible to realize a device having both the functions of the device. Furthermore, the mounting position and mounting direction of the various devices according to the present invention on the automatic guided vehicle 1 are as follows:
In addition to the vertical direction to the upper part of the car body and the main beam, various methods are possible.

In addition, the arrangement of the two photoelectric sensors in the light receiving device is as follows:
Fig. 5 shows a sensor installed with steps, but it would be possible to split the light using a semi-transparent mirror or prism so that both sensors could receive flat light beams at the same time without interfering with each other. A similar effect can be obtained.

Furthermore, the photoelectric sensor can be used not only as a linear position sensor but also as long as it can read the light receiving position, such as an integrated photo diode array or a line image sensor.

〔Effect of the invention〕

As explained above, since this invention emits a light beam having a vertically long and horizontally narrow cross-sectional shape, the tolerance for vertical movement of the traveling moving object is large, and the vertical field of view of the light receiving device and the light receiving sensor is small. Furthermore, it is possible to obtain an optical signal with a high S/N ratio without a decrease in light reception time at the apogee.

In addition, the lateral deviation amount and attitude angle of the traveling moving body with respect to the light beam are simultaneously detected by a plurality of sensors that are spaced apart at a predetermined interval in the light beam irradiation direction and receive the light beam simultaneously without mutual interference. Therefore, the steering of the traveling vehicle can be quickly corrected and the traveling accuracy can be improved.

The traveling vehicle is also equipped with a target position detection device that receives a light beam, reflects at least part of it to the side of the traveling vehicle, and detects the stop position of the traveling vehicle by receiving the reflected light reflected at the target position. Since it is installed in
Moreover, highly accurate target position information including the attitude of the traveling vehicle can be quickly obtained. In addition, the target position only needs to have the function of reflecting the light beam from the target position detection device and does not require any special positioning means, so it is possible to configure an inexpensive system even when multiple target positions are installed. can.

Further, if the light receiving device and the target position detecting device are shared by using an optical position detecting sensor based on the same principle, it is possible to configure the device to have the functions of both devices, and an inexpensive detecting means can be obtained.

Further, by making both of these devices movable and rotatable so that they can always follow the light beam, the field of view of both devices and the dimensions of the photoelectric sensor can be reduced. In addition, if it is possible to read the amount of movement and turning angle of both devices, it will not only be possible to correct the trajectory on the main passage, but also for moving vehicles that require complex steering control such as moving the vehicle closer to its width or driving diagonally. Applicable.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing a light guiding device according to the present invention, FIG. 2 is a perspective view showing an example of a light projecting device according to the present invention, and FIGS. Schematic configuration diagrams showing other examples, No. 4
Figure a is a diagram explaining the principle of the linear position sensor, Figure b is its output waveform diagram, Figure 5 a is a plan view showing the principle of the light receiving device according to the present invention, Figure b is a front view of the same, Figure 6 7 is a plan view showing another example of mounting the light receiving device on the moving vehicle, and FIG. 8 is the light receiving device shown in FIG. 7. 9A is a plan view showing the configuration of the main part of the light receiving device, FIG. 9B is a front view, and FIG. 9C is a front view of the same. A side view, FIG. 10 is a perspective view showing the movement and rotation mechanism of the light receiving device, and FIG. 11 is a plan view showing the principle of the target position detection device according to the present invention.
FIG. 12 is a perspective view showing an example of the target position detection device, FIG. 13 is a perspective view showing another example of the target position detection device, FIG. 14a is a plan view showing one specific example of the target position detection device, FIG. 15 is a side view, FIG. 15 is a side view, and FIG. 15 is a perspective view showing an example of a light-guided unmanned transportation system to which a light projecting device, a light receiving device, and a target position detecting device according to the present invention are applied. , FIGS. 16a and 16b are views corresponding to FIG. 1 showing the conventional light guiding device, FIG. 17 is a detailed view of the conventional device shown in FIG. 16b, and FIG. 18 is a diagram of the light receiving device shown in FIG. 17. It is a detailed view. 1: Automatic guided vehicle, 3: Laser light source, 10,5
8: Light receiving device, 15: Horizontal drive mechanism, 16: Light receiving device rotation mechanism, 40: Optical system, 45: Cross-sectional shape of flat light beam, 50: Target station, 51,
51a, 51b: Small reflecting mirror, 52: Branching mirror, 53, 53a, 53b: Photoelectric element, 59: Target position detection device, S ₁ , S ₂ : Linear position sensor, In each figure, the same reference numerals are the same or The corresponding portion shall be shown.

Claims (1)

[Scope of Claims] 1. A light projecting device installed at a fixed point on the ground side and emitting a light beam having a vertically long and horizontally thin cross-sectional shape, and a light projecting device installed on a traveling moving body and arranged at a predetermined interval in the direction of irradiation of the light beam. a light-receiving device that simultaneously detects the amount of lateral deviation and attitude angle of the moving vehicle with respect to the light beam using a plurality of light-receiving sensors that simultaneously receive the light beams without interfering with each other; a target position setting device that sets a target position for stopping the moving vehicle and reflects the light beam when it is irradiated; A traveling movable body characterized by comprising a target position detection device that reflects a part of the reflected light to the side of the movable body and detects a stop position of the movable body by receiving the reflected light reflected at the target position. light guiding device. 2. The light guiding device for a traveling moving body according to claim 1, wherein the light projecting device emits a light beam that is formed by parallel sweeping and has a vertically long and horizontally narrow cross-sectional shape. 3. A light guide device for a traveling moving object according to claim 1 or 2, characterized in that at least one of the light receiving device and the target position detecting device is capable of horizontal movement and horizontal rotation. .