JPH0379724B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention relates to a control device for an electric vehicle running on a predetermined road, which detects a permanent magnet provided on the road with a detection coil, The present invention relates to a device that controls the running of an electric vehicle according to the detection signal.

(b) Conventional technology Conventionally, magnetic fields have been developed by detecting the alternating magnetic field generated by passing an alternating current through induction wires buried in the road surface, or by providing wires with different reflection efficiencies on the road surface.
Vehicles that guide an electric vehicle along the line by optically detecting this line are applied to golf carts, transport vehicles, and the like.

In this type of conventional device, in order to stop or decelerate an electric vehicle, a permanent magnet is buried in the road surface, and the magnetic force is detected by a detection coil (Japanese Patent Publication No. 50-9956). In this case, since the magnet detection voltage of the detection coil is proportional to the running speed of the electric vehicle, in order to obtain a different position signal,
Even if a plurality of permanent magnets with different magnetic forces are used, the detected voltage changes depending on the running speed of the electric vehicle, so it is not possible to use a large number of permanent magnets with different magnetic forces.

(c) Problems to be solved by the invention The present invention was invented in view of the above points, and converts the detection voltage of the detection coil into a signal that is not affected by the running speed of the electric vehicle body, and converts the detection voltage of the detection coil into a signal that is This is an attempt to obtain different position signals using magnets.

(d) Means for solving the problem In order to solve the problem, the control device for an electric vehicle according to the present invention includes a detection coil means for detecting the magnetic field strength of a permanent magnet provided on the running path of the electric vehicle body. , a divided voltage generating means, a comparing means for comparing an output of the divided voltage generating means and an output of the detection coil means, and a control circuit for controlling running of the electric vehicle main body based on the output of the comparing means. means, and the divided voltage generating means generates as an output a voltage obtained by dividing the detected voltage obtained by detecting the speed of the electric vehicle body in accordance with the magnetic field strength of each of the permanent magnets. It is characterized by the fact that it does.

(e) Effect The output voltage of the detection coil means and the output voltage of the divided voltage generation means are both proportional to the running speed of the electric vehicle body, and the differential voltage between the two output voltages is mathematically It is the product of the speed term and a term unrelated to the running speed, and the running speed is positive and is related to the magnitude of the differential voltage. Therefore, when the two output voltages are used as two inputs of the comparison means, the output of the comparison means becomes high or low depending on whether the term unrelated to the traveling speed is positive or negative, and is not related to the magnitude of the traveling speed. It becomes something you don't do. In addition, the term unrelated to the traveling speed is determined whether positive or negative depending on the strength of the magnetic force of the permanent magnet and the magnitude of the proportionality constant in the output voltage of the divided voltage generating means, and the position signal corresponding to the permanent magnet with different magnetic force is determined. Obtainable.

(f) Examples An embodiment of the present invention will be described based on the drawings.

FIG. 2 is a diagram showing the principle configuration of an electric vehicle. In this drawing, 1 is the electric vehicle body, and at least 1
drive wheels 2 and at least one guide wheel 3. The drive wheel 2 is driven by a drive motor 4, the guide wheel 3 is driven by an angle control motor 5, and each motor 4, 5 is controlled by a drive circuit 6 or 7, respectively. Both drive circuits are controlled based on commands from the control circuit means 8, and are each provided with a pulse width modulation circuit, by which each motor 4, 5 is smoothly controlled.

Reference numeral 9 denotes a first detection means for detecting a predetermined guide route, and based on the output of this means, a control command from the control circuit means 8 is given to the drive circuit 7.
The guide wheels 3 are made to follow the guide line. In this case, the pulse width modulation circuit included in the drive circuit 7 causes the vehicle to gradually follow the guide line when it deviates from the guide line. The first detection means 9 includes:
When the guide line is equipped with a guide line that is supplied with alternating current, the alternating magnetic field from this guide line is detected. Also, when the guide line is equipped with lines with different reflection efficiencies, is to optically detect this line.

Reference numeral 10 denotes a manual operation section, which includes a control box and a brake lever, and the control box has notches such as "fully automatic,""passing a stop,""releasebrake,""park,""lowspeed," and "high speed." The notches are switched by a selector and each notch starts operating by pressing a start button.
"Full automatic" and "pass through stop" notches are used when guiding the vehicle along a predetermined guidance route.
The "brake release" notch is used for manual operation. The "low speed" and "high speed" notches are used when the vehicle is driven electrically outside the guidance line under manual steering control. The drive circuits 6 and 7 and the brake means 12 are controlled by commands from the operating section 10 or by commands from the second detection means 11 for detecting obstacles, for example.

Reference numeral 13 denotes a detection coil means for detecting a permanent magnet 14 provided on the guideway surface. This means includes a detection coil 15, an amplifier 16 for amplifying the detection output of this coil, and a waveform processing circuit 17 for processing the output of this amplifier into a waveform.
The output of is inputted to the control circuit means 8.

Reference numeral 19 denotes a speed voltage generating means as a divided voltage generating means, which detects a voltage according to the traveling speed of the electric vehicle body 1, and includes wheels of the electric vehicle body 1,
For example, one or more permanent magnets 20 are attached to the induction wheel 3, and a magnetic sensor 21 that senses the magnetic force of the permanent magnet is provided, the magnetic sensor output is used as a speed pulse signal, and frequency-voltage conversion is performed based on this signal. A voltage is generated in the circuit 22, and this output voltage is inputted to the control circuit means 8.

The control circuit means 8 controls the motor drive circuits 6, 7, the brake means 12, etc. based on each input signal, but regarding the detection of the permanent magnet 14 provided on the guideway surface, as shown in FIG. , four comparator means 23 to 26, and a voltage dividing circuit 2 that divides the output voltage of the speed voltage generating means 19 using resistors 27 and 28.
9. The waveform processing circuit 17 of the detection coil means 13 includes a phase inversion circuit 30, where the output voltage of the amplifier 16 is e _N and the phase inversion output voltage is e _s
Then, the output voltage e _N is input to the (+) terminals of the second and fourth comparator means 24 and 26, and the output voltage e _S
is input to the (+) terminals of the first and third comparator means 23, 25. On the other hand, if the output voltage of the speed voltage generating means 19 is e ₁ and its partial voltage is e ₂ , the output voltage e ₁ is input to the (-) terminals of the first and second comparator means 23 and 24, The output voltage e ₂ is the third and fourth
It is input to the −) terminals of the comparator means 25 and 26.

As shown in FIG. 3, a detection coil 15 disposed perpendicularly to the guideway surface 31 runs over the permanent magnet 14 embedded in the guideway surface 31 so that its magnetization direction is perpendicular to the guideway surface 31. passes at a speed v, the magnetic flux linkage characteristic of the detection coil 15 is the solid line characteristic 3
2, whereas the detection voltage characteristic of the detection coil 15 is a broken line characteristic 33.

The detected voltage e in this case is e=-N・dφ/dt, and if the distribution function of magnetic flux (φ) is (x), then e=-N・d/dx(x) ・dx/dt=K ₁・Φ(x)・v. Here, (N) is the number of turns of the detection coil 15,
(K ₁ ) is a constant (=-N), (Φ(x)) is the rate of change of the flux linkage distribution (=d/dt(x)), (v) is the velocity (= dx/dt), (x ) is distance, and (t) is time.

From the formula, if the amplification factor of the amplifier 16 is K ₂ ,
The output voltage e _N of the amplifier 16 is: e _N =K ₂ e=K ₁ K ₂・Φ(x)・v=K・Φ(x)・v However, K=K ₁ K _2The output voltage e with phase inversion _S becomes e _S =−e _N. In this way, the output voltages e _N and e _S become functions of speed (v). On the other hand, the output voltage e ₁ e ₂ of the speed voltage generating means 19 is e ₁ = a ₁ v, e ₂ = a ₂ v (however, a ¹ and
a ² is a constant). Therefore the comparator means 23-26
As _{a representative} example of the case of the comparator means ₂₄ , the input _of Therefore, the sign of (e _N −e ₁ ) is determined by the sign of the term {KΦ(x)−a ₁ }.
In this term, (K) and (a ₁ ) are constants, and (Φ(x))
only is a variable.

The output of the comparator means is equal to the potential difference between the two inputs (e _N −
e ₁ ), and its magnitude does not matter, so it is determined depending on whether the term {KΦ(x)−a ₁ } is positive or negative.

This means that when detecting the permanent magnet 14, it is not affected by the speed (Φ(x)), that is, it is only related to changes in the magnetic flux.

In addition, the sign of the term {KΦ(x)−a ₁ } is determined by the size of the constant (a ₁ ), and depending on the size of this constant (a ₁ ), the permanent magnet 14 It is also possible to detect the magnitude of the magnetic flux density B. The polarity of the permanent magnet 14 and the magnitude of the magnetic flux density B are shown in the figure when the outputs of each of the comparator means 23 to 26 shown in FIG. 1 are generated.

Note that the waveform processing circuit 17 in FIG. 1 may be omitted.

In this case, the output voltage e _N may be applied to the (-) terminals of the first and third comparator means 23, 25, and the output voltage e ₁ may be applied to the (+) terminals thereof.

(G) Effects of the Invention The present invention provides an output voltage of a detection coil means for detecting a permanent magnet provided on the running path of an electric vehicle, and a divided voltage generating means for generating a voltage according to the running speed of the electric vehicle body. Since the output voltage is compared with the output voltage using the comparator means, the detection of the permanent magnet can be performed without the influence of the running speed, and it can be made to depend on the magnetic force of the permanent magnet, so it is possible to detect the permanent magnet with different magnetic forces. By using a large number of permanent magnets, it is possible to obtain many different position signals, and it is also possible to control the running of the electric vehicle body more precisely.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a circuit diagram of the detection coil means, speed voltage generation means, and control circuit means, FIG. 2 is a configuration diagram of the electric vehicle body, and FIG. 3 is a permanent magnet, FIG. 3 is an explanatory diagram of the relationship between a detection coil and detection coil flux linkage characteristics. 1...Electric vehicle body, 14...Permanent magnet, 13...
...Detection coil means, 19...Speed voltage generation means,
23-26... Comparator means, 8... Control circuit means.

Claims (1)

[Claims] 1. Comparison of a detection coil means for detecting the magnetic field strength of a permanent magnet provided on the running path of the electric vehicle body, a divided voltage generation means, and an output of the divided voltage generation means and an output of the detection coil means. and control circuit means for controlling running of the electric vehicle main body based on the output of the comparison means, and the divided voltage generating means generates a detected voltage that detects the speed of the electric vehicle main body. A control device for an electric vehicle, characterized in that the control device for an electric vehicle generates as an output a divided voltage corresponding to the magnetic field strength of each of the permanent magnets.