JPS61166608A - Position detecting method of unmanned truck - Google Patents

Abstract

PURPOSE:To detect the position of an unmanned truck during its drive by detecting the pass of the truck over two pieces of magnets with two magnetic sensors set on the truck and calculating the two-dimensional position of the truck from the distance travelled after the truck passed through those magnets. CONSTITUTION:Two magnets 2 and 3 are set on the driving route of an unmanned truck 4 so that they cross the driving route with a prescribed angle alphasecured on the extended crossing lines. When the truck 4 passes between the magnets 2 and 3, the steering angle of the truck 4 is fixed. Then two magnetic sensors 5 and 6 set on the truck 4 deliver detection outputs when the truck 4 passes over both magnets 2 and 3. Meanwhile a distance beta1 travelled is calculated and at the same time a distance beta2 is also calculated when the truck 4 travels between both magnets. These distances beta1 and beta2 are used as parameters to calculate the two-dimensional position of the truck 4 in the form of the two-dimensional coordinates obtained on the basis of the crossing point between two lengthwise extended lines of both magnets 2 and 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a position detection device for an automatic guided vehicle that detects the two-dimensional position of an automatically traveling automatic guided vehicle while the vehicle is traveling.

[Prior Art] Automated guided vehicles have conventionally been used to automatically transport parts, luggage, etc. in warehouses, factories, etc.

By the way, the above-mentioned automatic guided vehicles include automatic guided vehicles that use a guide device that travels using guide lines, guide rails, etc. provided on the traveling route as route guidance, and automatic guided vehicles that store the traveling route in advance and use information such as the number of rotations of the wheels and the steering angle. There is an automatic guided vehicle that does not use a guidance device that automatically travels while comparing its own position determined from the following information.

In the case of automatic guided vehicles using the former guide device, it is necessary to install guide lines, guide rails, etc. on the travel route, which takes time and effort, and the route cannot be easily changed. Due to this problem, in recent years, automated guided vehicles that do not use the latter guide device and can run completely autonomously have become promising.

However, in the case of this type of automated guided vehicle, if the vehicle simply recognizes its own position based on the number of rotations of the wheels, steering angle, etc., the detection errors from each sensor will be accumulated, and in some cases the route will be completely different from the target route. The vehicle may end up driving along the route.

In recent years, countermeasures against this problem have been, for example, installing cameras on automatic guided vehicles to capture predetermined marks placed near the driving route, and detecting the position of the automatic guided vehicle based on the size of the marks, or using ultrasonic waves near the driving route. By installing multiple lighthouses that emit signals such as The idea is to correct the position if the

[Problems to be Solved by the Invention] However, in the conventional method for detecting the position of an automatic guided vehicle as described above, in order to capture marks near the travel route with a camera installed on the automatic guided vehicle, it is difficult to detect marks near the traveling route. There are problems such as the need to slow down or stop the guided vehicle, and the need to install a lighthouse near the travel route.Furthermore, although the position of the automated guided vehicle can be detected, the direction of the vehicle cannot be detected. Ta.

Therefore, the present invention was made to solve the above problem, and by simply installing two magnets on the travel path of the automatic guided vehicle, the two-dimensional position of the vehicle can be detected well while the vehicle is traveling. It is an object of the present invention to provide a method for detecting the position of an automatic guided vehicle, which can also detect the direction of the vehicle body.

Means for Solving Problem E] The configuration of the present invention to achieve such an object is as shown in FIG. In addition to providing book magnets, magnetic sensors that output detection signals on the magnets are provided at two predetermined locations on the automated guided vehicle, and when the automated guided vehicle passes the two magnets, its two-dimensional position (Pl) When the automatic guided vehicle passes between the two magnets, at least the steering angle of the automatic guided vehicle is fixed, and the magnetic Based on the output signal from the sensor, (P2) when the automatic guided vehicle passes over each of the above magnets, the traveling distance during which each of the magnetic sensors outputs a detection signal, and (P3) the automatic guided vehicle An automatic guided vehicle characterized by: calculating the traveling distance when traveling between the magnets, and (P4) calculating the two-dimensional position of the automatic guided vehicle using the calculated traveling distance as a parameter. The gist of this paper is the position detection method.

First, two magnets that cross the travel path of an automatic guided vehicle at different predetermined angles used to realize the method of the present invention are, for example, as shown in FIG. , magnets 2.3 arranged to form a predetermined angle α on the extension line in the longitudinal direction, and magnetic sensors 5.6 provided at two predetermined locations on the automatic guided vehicle 4.
Accordingly, the time when the automatic guided vehicle 4 passes over the magnet 2.3 is detected.

In (Pl) of FIG. 1, the automatic guided vehicle 4
When passing the magnet 2.3, the magnetic sensor 6 outputs a detection signal on at least the magnet 3, and the magnetic sensor 6 on the magnet 2 outputs a detection signal.
Pl and the steering angle of the automatic guided vehicle 4 may be fixed until the output of the detection signal.

Also, the traveling distance calculated in (P2) is the distance for each magnet 2.
When the automatic guided vehicle 4 passes over 3, the two magnetic sensors 5
, 6 are the distances traveled by the automatic guided vehicle 4 while each outputs a detection signal. For example, when the automatic guided vehicle 4 passes over the magnet 3, as shown in FIG. The travel distance β1 from the position indicated by the solid line to the position indicated by the dotted line is calculated.

Further, the traveling distance calculated in (P3) is the traveling distance that the automatic guided vehicle 4 travels between the two magnets 2.3, and is the distance β2 shown in FIG. 2.

In addition, when calculating each mileage in (P2) and (P3) above, for example, a method of calculating the mileage from the vehicle speed and the travel time, a method of calculating the mileage by integrating the number of rotations of the wheels, etc. , can be carried out by various methods.

Next, in (P4), a two-dimensional position is calculated using the travel distance determined in (P2) and (P3) above as a parameter, but the two-dimensional position determined here is the magnet 2 and! & It is expressed as a two-dimensional coordinate based on the point 0 where the longitudinal extension of the magnet intersects.

[Function] As described above, in the automatic guided vehicle position detection method of the present invention, the two magnetic sensors 5 and 6 detect the passage of the automatic guided vehicle over the magnet 2 or 3 while the automatic guided vehicle is running, and the automatic guided vehicle is submerged in water after passing. Its two-dimensional position is calculated based on the distance. Therefore, as an automated guided vehicle, the position can be detected while the vehicle is running without slowing down or stopping, and since the two-dimensional position required is a coordinate based on a fixed point, the absolute position can be detected without slowing down or stopping. It can be done.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is a schematic system diagram showing the automatic guided vehicle of this embodiment and its traveling route, and 10 is a diagram showing the automatic guided vehicle 11 and 12 crossing the traveling route of the automatic guided vehicle 10, and a predetermined line on the extension line of the automatic guided vehicle 10. Magnets 13 and 14 arranged to form an angle ψ
represent a magnetic sensor configured to output a pulse signal when passing over the magnet 11 or 12, respectively.

Here, the magnets 11 and 12 are magnets polarized in the width direction, as shown in FIG. 4, and the magnets ``!''''? 13
71F1 i“1iE11 <51.1.”127 inches
1j, it is configured to output a pulse signal at the polarization point. That is, magnetic sensors 13 and 14
As shown in FIG. 5, the vertical magnetic field detector detects the magnetic field, the horizontal magnetic field detector detects the horizontal magnetic field as shown in FIG. It is basically composed of a detection circuit that outputs pulse signals at polarization points of N and S poles.

Note that the arrows in FIGS. 5 to 7 above indicate the magnetic sensor 1.
3 (or 14) indicates the direction of movement on the magnet 11 (or 12).

Next, FIG. 8 shows a schematic configuration diagram of a control device mounted on the automatic guided vehicle 10 for detecting the position of the automatic guided vehicle 10 and correcting the traveling route. 17 is a steering angle adjustment member that adjusts the steering angle of the automatic guided vehicle 110, and 18 is a vehicle speed that controls the vehicle speed. The control member 20 receives signals from the magnetic sensors 13, 14 and the rotation speed sensor 16, detects the position of the automatic guided vehicle 10, and detects when the automatic guided vehicle 1o deviates from the preset travel route. In the case where the automatic guided vehicle 10 is present, it represents an electronic control circuit that outputs a control signal to the steering angle adjustment member 17 and the vehicle speed control member 18 to correct the trajectory of the automatic guided vehicle 10.

The electronic control circuit 20 includes an input circuit 21 that inputs signals from each of the sensors, and a C that executes the arithmetic processing.
PU22, ROM23 in which control programs and arithmetic formulas, etc. for executing the arithmetic processing are stored in advance, and RAM2 in which data used in executing the arithmetic processing is temporarily read and written.
4. Count the pulse signal from the rotation speed sensor 16,
A counter 25 used to calculate the travel distance of the automatic guided vehicle, an output circuit 26 used to output control signals to the steering angle adjustment member 17 and vehicle speed control member 18, and a path for data and control signals that connects each of the above parts. It is comprised of a pass line 27, and a power supply circuit 28 that supplies power to each of the above-mentioned parts.

Next, the automatic guided vehicle position detection process of this embodiment, which is the main process related to the present invention, will be explained along the flowchart shown in FIG.

As described above, this process is carried out by the magnetic sensors 13, 14,
and a process executed in the electronic Ill t11 circuit 20 based on the detection signal from the rotation speed sensor 16,
First, in step 101, it is determined whether a detection signal is output from the magnetic sensor 13 (or 14). Then, the automatic guided vehicle 10 approaches the magnet 11, and the magnetic sensor 13
When the detection signal is output from (or 14), the process moves to the following step 102, and the control signal for the steering angle adjustment member 17 is fixed in order to fix the steering angle to the current running state.

Next, in step 103, the rotation speed sensor 16
In order to count the pulse signals output from the counter 25, the counter 25 starts counting, and the process moves to the next step 104. In step 104, the magnetic sensor 14 (
or 13) determine whether the detection signal is output,
It is executed repeatedly until the detection signal is output.

Step 1 that follows when it is determined in step 104 that a detection signal is output from the magnetic sensor 14 (or 13)
05, the value of the counter 25 whose counting was started in step 103 is read and reset, and the process proceeds to step 106. In step 106, the reset counter 25 starts counting again, and the process moves to step 107.

In step 107, based on the value of the counter 25 read in step 105, the magnetic sensor 13 (or 14) outputs a detection signal when passing over the magnet 11,
Next, the traveling path 1111L on which the automatic guided vehicle 10 traveled until the magnetic sensor 14 (or 13) outputs a detection signal
Calculate 1. Since the rotation speed sensor 16 outputs a pulse signal in accordance with the rotation of the wheel, this calculation can be easily performed by multiplying the distance traveled by the automatic guided vehicle per pulse.

7″～y7108′″# &) 74*・1′2′″′
It is determined whether the first detection signal detected at 71.1o1 when traveling on the magnet 11 is the detection signal output from the magnetic sensor 13.

If the detection signal is output from the magnetic sensor 13, the process proceeds to step 109, and the entry angle θ of the automatic guided vehicle 10 with respect to the magnet 11 is calculated using the following equation.
Calculate 1. In the above equation, the approach angle is the separation distance between the magnetic sensors 13 and 14.

On the other hand, if it is determined in step 108 that the first detection signal when traveling over the magnet 11 is not output from the magnetic sensor 13, the process proceeds to step 110, where the approach angle θ1 is calculated using the following formula. .

Here, each of the above equations is as shown in FIG. 10 or 11, when the automatic guided vehicle 10 moves from the A position to the B position, the line a-a-1b-b- connects the magnetic sensors 13 and 14. The approach angle θ1 is calculated by approximating that they are parallel and subtracting π/2, and if the detection signal detected in step 101 is from the magnetic sensor 13, it is shown in FIG. Thus, the required approach angle θ1 is an obtuse angle, and conversely, if the detection signal is from the magnetic sensor 14, the approach angle θ1 is an acute angle, as shown in FIG.

In this way, when the approach angle θ1 of the automatic guided vehicle 10 with respect to the magnet 11 is calculated in step 109 or 110, the process moves to the subsequent step 111, where the automated guided vehicle 10
approaches the magnet 12, and the magnetic sensor 14 (or 13)
It is then determined whether a detection signal is output. When the detection signal □ is output from the magnetic sensor 14 (or 13), the subsequent step 112 is executed, the value of the counter 25 is read and reset, and the process proceeds to step 113, where the counter 25 starts counting.

Next, in step 114, similarly to step 107, based on the value of the counter 25 read in step 112, when passing over the magnet 11, the magnetic sensor 14 (or 13
) After the detection signal is output from the magnetic sensor 14 (or 13) when passing over the magnet 12, the distance L2 traveled by the automatic guided vehicle 10 is calculated.

Then, the process moves to step 115, and this time the magnetic sensor 1
3 (or 14) to determine whether a detection signal is output.

Step 116 follows when it is determined in step 115 that a detection signal has been output from the magnetic sensor 13 (or 14).
, read the value of counter 25, reset it,
The process moves to the next step 117.

In step 117, similarly to step 107 or step 114, a detection signal is output from the magnetic sensor 14 (or 13) when passing over the magnet 12, until the detection signal is output from the magnetic sensor 13 (or 14). During this period, the distance traveled by the automatic guided vehicle 10 is calculated as 3.

Next, in step 118, similarly to step 108, it is determined whether or not the first detection signal detected in step 111 when traveling on the magnet 12 is the detection signal output from the magnetic sensor 13. do. If the detection signal is output from the magnetic sensor 13, the process proceeds to step 119, and the approach angle θ of the automatic guided vehicle 10 with respect to the magnet 12 is calculated using the following equation.
2 is calculated, and on the other hand, if the detection signal is output from the magnetic sensor 14, the process moves to the following step 120,
The approach angle θ2 is calculated from the following formula. Note that this equation is the same as the calculation equation explained for the approach angle θ1 ejection.

Next, in step 121, the approach angle θ1 of the automatic guided vehicle 10 with respect to the magnet 11 determined in step 109 or 110 is changed to the approach angle θ2 of the automatic guided vehicle 10 with respect to the magnet 12 determined in step 119 or 120.
and the angle Φ made by the two magnets 11 and 12 on their extension lines
In other words, it is determined whether the automatic guided vehicle 1o is traveling straight when traveling between the magnets 11, 1 and 12. Then, when it is determined that the vehicle has traveled straight at θ1-θ2+φ, the process moves to the following step 122, and the automatic guided vehicle 10 shown in FIG. The distance represents the distance traveled by the following type people carrier 10 between the magnets 11 and 12.

On the other hand, if it is determined in step 121 that it is not θ1-θ2+ψ, the process proceeds to step 123, where the distance is calculated using the following equation.

When the distance is calculated in step 122 or step 123, the process moves to the following step 124, and the 2nd point of the intersection O is
The deviation X of the automatic guided vehicle 10 in the X direction with respect to the dimensional position (XO, YO) is calculated using the following formula % formula %, and the process proceeds to step 125,
The deviation Y in the Y direction with respect to the two-dimensional position (XO, YO) of the intersection O of the automatic guided vehicle 10 is calculated using the following formula %, and the two-dimensional position (X , Y). and then step 126
Then, the direction of the automatic guided vehicle 10 on the lit&512 is calculated using the following formula % formula %, and the processing of this routine ends.

In the above equation, φ is the X of the magnet 12 as shown in FIG.
This is an angle with respect to the direction, and is an angle that is set in advance when the magnets 11 and 12 are installed.

Next, the arithmetic expression for calculating the distance used in step 122 or 123 will be explained, taking as an example the case where the automatic guided vehicle 10 travels as shown in FIG. 12. In this embodiment, the distance is calculated as shown in FIG.
This is performed using the law of sine on a triangle OCD connecting the intersection point C1D between the traveling trajectory of the automatic guided vehicle 10 and each magnet 11.12 and the intersection point 0 on the extension line of the magnet 11.12.

The procedure is to first find the radius of the arc CD that is the traveling trajectory of the automatic guided vehicle 10. Since the angle reference between intersections C and D is shifted by ψ, the central angle C0-0 from intersection C to the intersection is (θ1-θ2-ψ). Further, the length of the arc CD is the travel distance between CD and CD of the automatic guided vehicle 10 (L2+).

becomes.

Next, find the angle OCD.

to c o = π-θ1 + Δθ3 therefore becomes.

Therefore, the distance ML is as follows, and the arithmetic expression of step 119 is obtained.
...
On the other hand, in step 118, since the automatic guided vehicle 10 is traveling straight, the string length σ) is. Also θ
The distance can be calculated using 1-θ2+φ.

As explained above, in this embodiment, two magnets are installed on the travel route of the automatic guided vehicle so as to cross the route so as to form a predetermined angle on the extension line of the travel route, and the automatic guided vehicle is detected when passing over the magnets. Two magnetic sensors that output signals are installed at two predetermined locations on the automatic guided vehicle, and when passing one magnet, the travel distance is calculated while each magnetic sensor outputs a detection signal, and the distance traveled is determined for each magnet. The approach angle of the automatic guided vehicle is calculated, the travel distance between each magnet is determined, and the two-dimensional position and vehicle body direction of the automatic guided vehicle are calculated from the travel distance and the approach angle. Therefore, if the automatic guided vehicle position detection method of this embodiment is used, the absolute position and direction of the automatic guided vehicle can be detected while the automatic guided vehicle is traveling without stopping or slowing down, and the automatic guided vehicle position Control can be performed accurately. Further, there is no need to install a lighthouse or various devices near the travel route as in the past, and it is sufficient to simply place two magnets on the travel route. Furthermore, since the magnet may be a permanent magnet that does not require a power source, the equipment is simple and changes can be made easily. Furthermore, the magnets only need to be left in place so that they do not shift, and since they are not affected by dirt or external light, there is no need for maintenance.

[Effects of the Invention] As described in detail above, according to the method for detecting the position of an automatic guided vehicle of the present invention, the absolute position of the automatic guided vehicle can be accurately determined while the automatic guided vehicle is running without stopping or slowing down. It is possible to detect it, and also to detect its direction. Therefore, using this method, it is possible to accurately control the travel of the automatic guided vehicle. Furthermore, the method of the present invention requires only two magnets to be fixed on the travel route, without the need to provide various equipment such as a lighthouse that outputs a predetermined signal or a mark near the travel route as in the conventional method. Therefore, it can be realized without being affected by dirt or external light, and without the need for a power supply, and there is no need for maintenance management.
It will also be easier to change facilities.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the configuration of the present invention, FIG. 2 is an explanatory diagram for explaining the method of the present invention, FIGS. 3 to 12 show an embodiment of the present invention, and FIG. A schematic system diagram showing an example of an automatic guided vehicle and its traveling route, FIG. 4 is an explanatory diagram of the magnet 11 (or 12), and FIGS. 5 to 7 are explanatory diagrams of the configuration and operation of the magnetic sensor 3 (or 14). 8 is a schematic configuration diagram showing the configuration of the control device mounted on the automatic guided vehicle 1o, and FIG. 9 is an explanatory diagram showing the configuration of the control device mounted on the automatic guided vehicle 10.
70-chart showing the position detection process, FIGS. 10 and 11 are explanatory diagrams illustrating the calculation formula for calculating the distance used in the pot for the magnet 11 of the automatic guided vehicle 10. 2.3.11.12... Magnet 4.10... Automatic guided vehicle 5.6, 13.14... Magnetic sensor 20... Electronic control circuit

Claims (1)

[Scope of Claims] Two magnets are provided on the travel route of the automatic guided vehicle that cross the route at predetermined different angles, and detection signals are output on the magnets at two predetermined locations on the automatic guided vehicle. A method for detecting a position of an automatic guided vehicle that includes a magnetic sensor and detects a two-dimensional position of the automatic guided vehicle when the automatic guided vehicle passes between the two magnets. When passing, at least the steering angle of the automatic guided vehicle is fixed, and based on the output signal from the magnetic sensor, each of the magnetic sensors detects when the automatic guided vehicle passes over each of the magnets. Calculate the travel distance while outputting the signal and the travel distance when the automatic guided vehicle travels between each of the magnets, and calculate the two-dimensional position of the automatic guided vehicle using the calculated travel distance as a parameter. A method for detecting a position of an automatic guided vehicle, characterized by calculating the position of an unmanned guided vehicle.