JPS61285509A - Lateral displacement detector for guidance control of unmanned carrier - Google Patents

Abstract

PURPOSE:To omit a manual gain control operation for guidance control of an unmanned carrier by connecting an automatic gain controller between a waveform shaping circuit and a substractor and varying the frequency of the guidance signal which is flowed to a locus line. CONSTITUTION:The voltages VL and VR induced by the right and left pickup coils 12 and 13 are delivered to a waveform shaping circuit 14. The waveforms of the converted DC voltages DL and DR are smoothed by a smoothing circuit and delivered to an automatic gain control circuit 20 on the next stage. The circuit 20 can compensate automatically the variation of its gain if occurs by changing the sensitivities of both coils 12 and 13 in response to the changeover of the frequency of the guidance signal flowing to a locus line. Thus the gain of a fixed level can be secured at all times even though the frequency of the guidance signal is switched properly.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a lateral displacement detection device employed for guidance control of an electromagnetic induction type unmanned vehicle.

(Prior Art) Conventionally, the method of guiding an unmanned vehicle, such as an automatic guided vehicle, is to send a low-frequency guidance signal from a control device in a control room to one track line arranged on the traveling path of the guided vehicle, and As shown in the figure, the induced electromotive force induced in a pair of left and right pickup coils 1 and 2 provided on the bottom of the carrier is outputted to a rectifier circuit 5 via an amplifier 3 and a bandpass filter 4, respectively, and both rectifier circuits. The difference between the output voltages DL and DR from 5 (=
CH-DL) is obtained by a subtractor 6, the difference is taken as the amount of lateral displacement of the guided vehicle with respect to the track line, and the guided vehicle is guided along the travel path based on the amount of lateral displacement.

(Problem to be Solved by the Invention) However, when the frequency of the guidance signal sent to the track line changes, the sensitivity of the pickup coil 1.2 changes and the gain changes, so when changing the frequency to control the guidance of the guided vehicle, It was necessary to keep the gain constant each time the frequency changed, and the adjustment work was extremely troublesome.

The purpose of this invention is to solve the above problems: 1.
When guiding and controlling an automatic guided vehicle by changing the frequency of the guidance signal sent to the track line, there is no need to adjust the gain each time the frequency is changed, and there is no need for a changeover switch etc. for the adjustment. The present invention provides a lateral displacement detection device for guidance control of an unmanned vehicle.

Structure of the Invention (Means for Solving Problems) In order to achieve the above-mentioned object, this invention unmanned a pair of left and right pickup coils that detect guidance signals flowing in a track line arranged on a travel path of an unmanned vehicle. A waveform shaping circuit shapes the induced signals that are provided on the bottom of the car and induces each pickup coil based on the induced signal, and the difference between the two waveform-shaped induced signals is determined using a subtracter. A lateral displacement detection device for detecting the amount of lateral displacement between the track line and the unmanned vehicle, wherein an automatic gain adjuster is connected between the waveform shaping circuit and the subtracter for guidance control of the unmanned vehicle. Its gist is as follows.

(Function) Even if the sensitivity of the pickup coil changes by switching the frequency of the induction signal flowing through the track line and its gain fluctuates, the automatic gain adjuster compensates for the fluctuation. Even if the frequency of the guiding signal is changed as appropriate, a constant gain is always maintained.

(Example) An example embodying the present invention will be described below with reference to the drawings.

In FIG. 1, a pair of left and right pickup coils 12 and 13 provided on the front side of the bottom of the automatic guided vehicle 11 are connected to the automatic guided vehicle 11.
They are arranged symmetrically with respect to the center line in the traveling direction passing through the center position of the automatic guided vehicle 11, and each detects a low-frequency guidance signal flowing to a single track line (not shown) arranged on the travel path of the automatic guided vehicle 11. .

That is, both coils 12, 13 each output an induced voltage VLVR having a value relative to the distance to the track line. Therefore, when the automatic guided vehicle 11 is traveling with the center line of the guided vehicle 11 and the trajectory line aligned, the induced voltages VL and VR are equal; on the other hand, when they are not aligned, the induced voltages VL and VR are equal. The induced voltages VL and VR will not be equal.

The induced voltages VL and VR induced by the pair of left and right pickup coils 12 and 13 are respectively output to the waveform shaping circuit 14 as shown in FIG.

In this embodiment, the waveform shaping circuit 14 is composed of an amplifier 15, a bandpass filter 16, a rectifier circuit 17, and a smoothing circuit consisting of a capacitor 18 and a resistor 19. After being amplified, only a predetermined frequency band (in this embodiment, a frequency that matches the frequency of the guidance signal flowing through the track line) is extracted by a band-pass filter 16, and then converted into direct current by a rectifier circuit 17. Then, the converted DC voltages DL, D
The waveform of R is smoothed by a smoothing circuit and output to the automatic gain adjustment circuit 20 at the next stage. Therefore, the DC voltage DL,
The value of DR is the induced voltage VL.

It will change relative to the value of VR.

The automatic gain adjustment circuit 20 as an automatic gain adjustment device includes first and second multipliers 21 and 22, an adder 23, a subtracter 24,
It is composed of a constant setter 25 and an amplifier 26, and the DC voltage (hereinafter referred to as left DC voltage) DL based on the left pickup coil 12 is applied to the first multiplier 21, and the DC voltage based on the right pickup coil 13 is input to the first multiplier 21. DR (hereinafter referred to as right-side DC voltage) is output to the second multiplier 22. An adder 23 adds the output voltages ML and MR of the first and second multipliers 21 and 22 to obtain the sum Q.
(=ML + MR) is output to the subtracter 24.

The subtracter 24 subtracts this added value Q from a predetermined constant value C output from the constant setting device 25, and obtains the subtracted value P.
(=C-Q) is output to an amplifier 26 with an amplification factor of A. The amplifier 26 amplifies the subtracted value P of the subtracter 24 and outputs its output T (=P·A) to the first and second !
) is output to calculators 21 and 22. Therefore, the first multiplier 2
1's output voltage M[ is the product of the output lower and left side DC voltages D[, and the output voltage MR of the second multiplier 22 is the product of the output T and the right side DC voltage DR.

Note that the amplification factor A of the amplifier 26 is as shown in this embodiment.

is Q=C-D/ (1/A+D>=C...■However, [)
It is set in advance to a value such that =[)L +l)R.

Output voltage ML of the first and second multipliers 21 and 22
, MR are output to the subtracter 27 at the next stage.

Then, the subtracter 27 converts the output voltage MR into the output voltage ML.
The subtracted value Z (=MR-ML) is output as the amount of lateral displacement of the automatic guided vehicle 11 with respect to the track line.

That is, now the pickup coil 1 based on the frequency change of the induction signal of the pickup coil 12 and 13.
Let K be the gain fluctuation rate in 2.13, and let the left DC voltage based on the gain fluctuation rate K be Y (= to −DL>, and the right DC voltage DR@X (=K・DR>), then Q=T (X+Y) ・・・■T=
A-P=A・(C-Q) ・・・■Z=MR-
ML=T・(X−Y)...■. Then, from formulas ■, ■, and 2〇, the subtracted value Z, that is, the amount of lateral displacement, is Z=Q・(X−Y＞/ (X+Y) =C・(X−Y)/(X0Y) =C・(DR-DL) / (DR+DL>・・
・■ becomes.

Therefore, as is clear from the formula ■, the subtraction value Z, that is,
The amount of lateral displacement is not affected by changes in the gain fluctuation rate due to changes in the frequency of the induction signal, that is, changes in the sensitivity of the pickup coils 12 and 13.

The subtracted value Z output from the subtractor 27 is used as data for driving and controlling the steering wheels of the automatic guided vehicle 11 to cause the guided vehicle to travel along the track line. It is designed to be output to a controller that does not.

In this way, in this embodiment, even if the frequency of the guidance signal applied to the track line is changed, there is no need to adjust the sensitivity of the pickup coils 12, 13 in conjunction with the change, as in the conventional case. Moreover, since sensitivity adjustment is not performed, a gain switching circuit for the adjustment is not required.

Effects of the Invention As detailed above, according to the present invention, when guiding and controlling an automatic guided vehicle by changing the frequency of the guidance signal sent to the track line, there is no need to adjust the gain each time the frequency is changed. It is an industrially excellent invention as a lateral displacement detection device for guiding and controlling unmanned vehicles, since there is no need for a changeover switch or the like for the adjustment.

[Brief explanation of drawings]

Fig. 1 is a layout diagram of a pickup coil embodying this invention, Fig. 2 is an electric block circuit diagram of a lateral displacement detection device,
FIG. 3 is an electrical block circuit diagram of a conventional lateral displacement detection device. In the figure, 11 is an automatic guided vehicle, 12 and 13 are pickup coils, 14 is a waveform shaping circuit, 20 is an automatic gain adjustment circuit,
21. 22 are first and second multipliers, 23 is an adder, 2
4.27 is a subtracter, 25 is a constant setter, and 26 is an amplifier.

Claims (1)

[Scope of Claims] 1. A pair of left and right pickup coils are provided on the bottom of the unmanned vehicle to detect a guidance signal flowing through a track line arranged on the travel path of the unmanned vehicle, and each pickup coil is configured to detect the guidance signal flowing through the track line arranged on the travel path of the unmanned vehicle. A waveform shaping circuit shapes the induced signals induced by the waveform, the difference between the two waveform-shaped induced signals is obtained by a subtracter, and the difference is detected as the amount of lateral displacement of the unmanned vehicle with respect to the track line. A lateral displacement detection device for guidance control of an unmanned vehicle, the displacement detection device comprising: an automatic gain adjuster connected between the waveform shaping circuit and the subtracter. 2. The waveform shaping circuit includes an amplifier that amplifies the induced signal induced by the pickup coil, and a bandpass filter that extracts only a predetermined frequency band of the amplified induced signal.
A lateral displacement detection device for guidance control of an unmanned vehicle according to claim 1, comprising a rectifier circuit that rectifies the induced signal output from the bandpass filter. 3. The automatic gain adjuster each includes a multiplier that inputs the waveform-shaped induced signal output from each waveform shaping circuit, an adder that adds the outputs of both multipliers, and a predetermined addition value of the adder. a subtracter that performs subtraction between the constant value of the constant setter and the constant value of the constant setter, and an amplifier that amplifies the subtracted value of the subtracter by a predetermined amplification factor and outputs the output to each of the multipliers. A lateral displacement detection device for guidance control of an unmanned vehicle according to claim 1, which comprises: