JPH0423285B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stop position detection device for an unmanned vehicle.

Generally, unmanned vehicles need to be stopped in a fixed position for cargo handling work, etc., but in particular, unmanned vehicles of the trolley type must be able to transfer cargo to and from a platform placed parallel to the driving path. Although the accuracy of a car's stopping is the result of integrating many technologies, it is basically necessary to develop a technology that accurately detects the stopping position.

Conventionally, this type of stop position detection involves laying a guide line (stop line) perpendicular to the running path and detecting the current magnetic field flowing through the stop line, or creating a singular point in the magnetic field on the running path. The singular point is detected, and the stop position is detected based on the point in time when these detected magnetic fields reach a certain threshold value or more.

Therefore, the detection position fluctuates depending on road surface conditions, current fluctuations, threshold values, etc., making it impossible to accurately detect the stop position.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a stop position detection device for an unmanned vehicle that can accurately detect the stop position of an unmanned vehicle.

According to this invention, two stop position detection means are provided for detecting magnetic fields from a guide line (stop line) that is spaced a certain distance apart in the front-rear direction of the unmanned vehicle and perpendicular to the direction of travel, and the unmanned vehicle approaches the stop line. In addition, the stop position is accurately detected by detecting the point in time when the respective detection outputs of the two stop position detection means become equal.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

First, as shown in FIG. 1, two coils 1 and 2 having the same characteristics are arranged in the front-rear direction of an unmanned vehicle. These coils 1 and 2 are respectively located at a height h from the road surface 3 as shown in FIG.
The coils are arranged so that the distance between the centers of the coils is 2×Δx. In addition, these coils 1 and 2 are installed perpendicularly to the traveling direction of the unmanned vehicle, and are connected to a guide wire (stop wire) 4 through which an alternating current flows.
It is now possible to detect magnetic fields from

Now, when the unmanned vehicle moves forward in the direction of arrow A along the guide line 5 and approaches the stop line 4 as shown in FIG. 2, let the outputs of coils 1 and 2 be V ₁ and V ₂ , respectively. For example, V ₁ = μI/2π×K ₁ h/r ² / ₁ = μI/2π×K ₁ h/h ² + (
x−Δx) ² …(1) V ₂ = μI/2π×K ₁ h/r ² / ₂ = μI/2π×K ₂ h/h ² + (
x+Δx) ² ...(2). However, μ is the magnetic permeability, I is the current flowing through the stop wire 4, and K ₁ and K ₂ are constants each consisting of the number of turns of the coils 1 and 2 or the amplification factor of the amplifier that amplifies the signal from the coils. Furthermore, K ₁
= K ₂ is easy.

Now, if K ₁ =K ₂ and x=0, the above equations (1) and (2) completely match. Conversely, if a time point is detected where equation (1) and equation (2) match, it means that x is 0 at that time, that is, the unmanned vehicle has reached the stop position.

FIG. 3 is a block diagram showing an embodiment of the stop position detection device for an unmanned vehicle according to the present invention. In the figure, coils 1 and 2 apply outputs corresponding to the magnetic field from stop line 4 to detection rectifier circuits 10 and 11, respectively, as described above. The detection rectifier circuit 10 detects and rectifies the output from the coil 1 and adds it to the negative input of the differential comparator 12 and the addition point 13. The detection rectifier circuit 11 detects and rectifies the output from the coil 2. This is applied to the positive input of comparator 12 and the other input of summing point 13.

The comparator 14 detects that the unmanned vehicle approaches the stop line 4, that is, that it enters a predetermined area based on the stop line 4, and adds 1 point.
The addition output of No. 3 is compared with a preset level Vref, and when the addition output exceeds the level Vref, an enable signal is output to the comparator 12.

The comparator 12 inverts the output polarity when the two input levels match and the magnitude relationship of the two inputs changes.
When an enable signal is applied from , it becomes operational, and as shown in Figure 1, when the unmanned vehicle moves forward and comes to the stop position, the output of the comparator 12 changes from L level to H level, and when the unmanned vehicle moves backward. When the motor reaches the stop position, the output of the comparator 12 changes from the H level to the L level.

The differentiating circuit 15 takes the differentiation of the rising edge of the signal applied from the comparator 12, and outputs a pulse signal to the output terminal 17 at the rising edge of the input signal.
Further, the differentiating circuit 16 takes the falling edge differential of the signal applied from the comparator 12, and outputs a pulse signal to the output terminal 18 at the falling edge of the input signal.

Therefore, when a pulse signal is output from the output terminal 17, it can be detected that the unmanned vehicle has reached the stop position while moving forward, and when a pulse signal is output from the output terminal 18, it can be detected that the unmanned vehicle has reached the stop position while moving forward. , at that point, it can be detected that the unmanned vehicle has reached the stop position while reversing.

In addition, in this embodiment, when detecting the stop position,
Although the detection is performed from the point in time when the difference between the two stop line detection outputs becomes 0, the present invention is not limited to this.
Detection may be performed from the point in time when the ratio of two stop line detection outputs becomes 1.

As explained above, according to the present invention, when detecting the stop position of an unmanned vehicle, it is detected based on the point in time when two stop line (position) detection outputs match, so that the stop line current There are no detection errors due to changes in the detection position due to fluctuations, disturbances in magnetic flux density due to external structures near the stop line, or fluctuations in the threshold for detecting the stop position, and it is possible to always detect the correct stop position.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between an unmanned vehicle equipped with a magnetic field detection coil according to the present invention and a stop line;
FIG. 2 is a diagram showing the positional relationship between the coil and the stop line, and FIG. 3 is a block diagram showing an embodiment of the stop position detection device for an unmanned vehicle according to the present invention. 1, 2... Coil, 4... Stop line, 10, 11
...Detection rectifier circuit, 12, 14...Comparator, 1
5, 16... Differential circuit.

Claims (1)

[Scope of Claims] 1. A stop position detection control device for an unmanned vehicle that controls the unmanned vehicle to stop at a position of a guide line laid perpendicular to the direction of travel of the unmanned vehicle, comprising: first and second coils that are arranged at a predetermined distance in the longitudinal direction of the vehicle and output signals corresponding to the magnetic field from the guide wire; and an area detecting means for detecting entering the area; and an area detecting means that becomes operable when a detection output is output from the area detecting means, and outputs a coincidence detection signal when each detection output of the first and second coils coincides with each other. a calculation means for outputting; a first differentiating means for differentiating the rising edge of the coincidence detection signal; and a second differentiating means for differentiating the falling edge of the coincidence detection signal; 1. A stop position detection device for an unmanned vehicle, characterized in that it is determined based on the output of the means whether the stop position is reached while moving forward or the stop position is reached while moving backward.