JPH0336162Y2 - - Google Patents

Description

[Detailed explanation of the idea] This invention relates to a travel control device for an unmanned vehicle.

The applicant of the present application has proposed a travel drive motor, a speed control signal generation circuit that generates a speed control signal, a motor control circuit that controls the rotational speed of the travel drive motor based on an output voltage signal of the speed control voltage generation circuit,
A rotation speed detector detects the rotation speed of the travel drive motor, and a detection signal from the rotation speed detector is converted into a voltage signal corresponding to the rotation speed of the travel drive motor, so that the rotation speed of the travel drive motor corresponds to the specified speed. An unmanned vehicle has already been developed that is equipped with a speed control circuit that controls the output voltage signal of the speed control voltage generation circuit so as to maintain the rotational speed.

In such an unmanned vehicle, if a failure occurs in the speed control circuit, speed control becomes impossible, and the output voltage of the speed control signal generation circuit increases, which may cause the unmanned vehicle to run out of control.

This idea was created in view of the above-mentioned circumstances, and when a failure occurs in the speed control circuit and speed control becomes impossible, the vehicle speed can be forcibly slowed down, thus preventing runaway. The purpose is to provide a driving control device for an unmanned vehicle that can perform the following tasks.

The driving control device for an unmanned vehicle according to this invention is a driving control device for an unmanned vehicle having a speed control signal generation circuit, a vehicle speed control circuit, and a runaway prevention circuit, wherein the speed control signal generation circuit has a vehicle speed control circuit and a runaway prevention circuit. The vehicle speed control circuit generates a signal voltage corresponding to the vehicle speed range and controls the motor control circuit with the output. The runaway prevention circuit converts the rotational speed of the drive motor into a corresponding voltage signal and generates and outputs a vehicle speed control signal corresponding to the vehicle speed range, and the runaway prevention circuit includes a speed control failure detection circuit and a voltage drop circuit. The speed control failure detection circuit inputs a voltage signal corresponding to the rotational speed of the vehicle speed control circuit and an output voltage signal of the speed control signal generation circuit, detects a failure in the vehicle speed control circuit from the difference, and detects a failure. The voltage reduction circuit is characterized in that it receives the failure detection signal and generates and outputs a signal that reduces the output voltage of the speed control signal generation circuit.

Since the driving control device for an unmanned vehicle according to this invention has the above-mentioned configuration, it can detect that a failure has occurred in the speed control circuit and the speed cannot be controlled, and when it detects that the speed cannot be controlled, Vehicle speed can be reduced. Therefore, it is possible to prevent the unmanned vehicle from running out of control if the speed becomes uncontrollable.

Hereinafter, embodiments of this invention will be described in detail with reference to the drawings.

FIG. 1 shows a driving control device for an unmanned vehicle.
The unmanned vehicle is driven to travel by a drive motor 2.
The drive motor 2 is driven by the DC power supply 1. An excitation circuit 3 and a motor drive current control transistor 4 are connected in series to the drive motor 2 .

The excitation circuit 3 includes an excitation coil 3a, and a forward rotation changeover switch 3f and a reverse rotation changeover switch 3r for switching the connection of the excitation coil 3a. When a forward travel command is input to the forward/reverse setting device (not shown), the forward rotation changeover switch 3f is turned on (the contact piece is connected to the fixed contact a), and the reverse rotation changeover switch 3r is turned off (connected). one piece is connected to fixed contact b). On the other hand, when a reverse travel command is input, the forward rotation changeover switch 3f is turned off (connected to contact b), and the reverse rotation changeover switch 3f is turned off (connected to contact b).
r is turned on (connected to contact a). When a reverse braking control relay 67, which will be described later, is activated, the forward rotation changeover switch 3f is turned on, and the reverse rotation changeover switch 3r is turned on.

The travel control device includes a relay circuit 20 to which a vehicle speed range designation signal and an emergency stop command are input. The relay circuit 20 includes vehicle speed range control relays 21 to 24 and emergency input terminals connected between input terminals I1 to I4 for specifying vehicle speed ranges of 1st to 4th speeds, emergency stop command input terminal I5, and ground, respectively. A stop control relay 25 is provided.

In each vehicle speed range, the first speed is the slowest speed, and the speeds increase in the order of second, third, and fourth speeds. A backflow prevention diode 27 and an indicator light (light emitting diode) 26 are connected in parallel to each of the relays 21 to 25, respectively.

The emergency stop command input terminal I5 is also connected to the first speed relay 21. Each relay 21-25 is activated by applying an operating voltage to the corresponding input terminal I1-I5, for example, by a manual switch (not shown). 1st speed control relay 2
1 is also activated when an operating voltage is applied to the emergency stop command input terminal I5. Each manual switch is such that when one is turned on, the others are automatically turned off. The b contact 67b2 of the reverse braking control relay 67 is also connected to the emergency stop command input terminal I5.

The motor drive current control transistor 4 is controlled by a motor control circuit 40 that receives the output of the speed control signal generation circuit 30, and the output voltage VA of the speed control signal generation circuit 30 is controlled by the speed control circuit 50. Ru.

The speed control signal generation circuit 30 is for gradually accelerating and starting without impact, and is connected to the a contacts 21a1 to 24a1 of each vehicle speed range control relay 21 to 24 of the relay circuit 20, and the rise/fall control. It includes a circuit 31 and an operational amplifier (operational amplifier) 32.

A contacts 22a1 to 24a1 of the second to fourth speed control relays 22 to 24 are connected in parallel to each other. The rise/fall control circuit 31 includes a resistor 3
3, 34, 35b, a capacitor 36, and diodes 37, 35a.

A resistor 33 is connected in series to the A contact 21a1 of the first speed control relay 21, a resistor 34 is connected in series to the parallel circuit of the A contacts 22a1 to 24a1 of the second to fourth speed control relay 22; A charging circuit is formed by a diode 37 whose anode is connected to the input side of the resistor 33 and whose cathode is connected to the input side of the other resistor 34, and a capacitor 36 whose negative electrode is connected to the output side of both resistors 33 and 34. is configured.

A capacitor 36, a diode 35a whose anode is connected to the positive electrode of the capacitor 36, and a grounding resistor 35 connected to the cathode of the diode 35a.
A discharge circuit is constituted by b. The output of the charging circuit becomes the non-inverting input of the operational amplifier 32.

An operating voltage is applied to each of the a-contacts 21a1 to 24a1. The output voltage of the operational amplifier 32 is then sent to the motor control circuit 40 via the variable resistor 38 and the resistor 39.

When the a contact 21a1 of the first speed control relay 21 is turned on, a charging current flows to the capacitor 36 through the parallel circuit of the resistor 33 and the resistor 34, and the capacitor 36 is gradually charged. The input voltage of is gradually increased. Therefore, the output voltage VA of the speed control signal generation circuit 30 is:
As shown by VA1 in Fig. 2, the reference voltage gradually increases and when the charge amount of the capacitor 36 reaches the saturation amount, the reference voltage
It becomes VO1 (for example, 6V).

When any of the a contacts 22a1 to 24a1 of the second to fourth speed control relays 22 to 24 is turned on,
A charging current flows into the capacitor 36 via the resistor 34, and the capacitor 36 is gradually charged, and the input voltage of the operational amplifier 32 gradually increases accordingly.

Since the resistor 34 is larger than the combined resistance of the parallel circuit of the resistors 33 and 34, the output voltage VA of the speed control signal generating circuit 30 rises more slowly than VA1, as shown by VA2 in FIG. That is, it rises more slowly and reaches the reference voltage VO1.

In other words, the second speed range is larger than the first speed.
- When the fourth speed is specified, the unmanned vehicle reaches the specified speed more slowly than when the first speed is specified. Therefore, in this speed control signal generation circuit 30, the output voltage VA generally rises slowly no matter which vehicle speed range is specified, and when a larger vehicle speed range is specified, the output voltage VA rises slowly. The voltage VA rises more slowly. Therefore, a smooth start can be performed without any impact.

On the other hand, the A contacts 21a1 to 24a that were turned on
1 is turned off, the charge stored in the capacitor 36 is discharged to the ground side through the diode 35a and the resistor 35b, so that the reference voltage gradually rises to zero. Therefore, it is possible to stop smoothly without impact.

The motor control circuit 40 includes an operational amplifier 41 that amplifies the output voltage VA of the speed control signal generation circuit 30;
Consisting of a pulse generation circuit 42 that converts the output voltage of an operational amplifier 41 into a pulse signal having a pulse width proportional to the voltage, and a drive circuit 43 that drives the motor drive current control transistor 4 based on the output of the pulse generation circuit 42. has been done.

As the voltage VA input to the operational amplifier 41 increases, the pulse width (duty ratio) of the output signal of the pulse generation circuit 42 increases, so the ratio of the on time to the off time of the transistor 4 (conduction rate)
becomes larger. Therefore, the drive current of the travel drive motor 2 increases, the rotational speed of the travel drive motor 2 increases, and the speed of the unmanned vehicle increases. Conversely, when the voltage VA decreases, the speed of the unmanned vehicle decreases.

Although not shown, the power supply voltage for each circuit of the travel control device is supplied by an operating voltage generation circuit 10 whose power source is the DC power supply 1 of the drive motor 2. However, as described above, since the drive motor 2 is subjected to chopper control, the drive motor 2 generates a back electromotive force AC pulse, and this AC pulse may cause damage to each circuit element. .
Therefore, a chiyoke coil 5 for cutting off the alternating current component is connected between the input side of the drive motor 2 and the operating voltage generating circuit 10 to remove the alternating current pulse.

The speed control circuit 50 includes a rotation speed detector 51,
It is composed of an F/V conversion circuit 52, an amplifier circuit 53, and a voltage control transistor 54.

The rotational speed detector 51 detects the rotational speed of the travel drive motor 2 and outputs a pulse signal with a frequency proportional to the rotational speed. The F/V conversion circuit 52 converts the pulse signal output from the rotational speed detector 51 into a voltage representing its frequency. Amplification circuit 53
amplifies the output voltage VB of the F/V conversion circuit 52 with a smaller amplification degree as the designated speed (first to fourth speed) is faster. The voltage control transistor 54 is
The output voltage VA of the speed control signal generation circuit 30 is controlled based on the output voltage VC of the amplifier circuit 53 so that the output voltage VB of the F/V conversion circuit 52 becomes a voltage representing the designated speed.

The amplifier circuit 53 includes an operational amplifier 55 and an amplification degree setting circuit 56. The non-inverting input terminal of the operational amplifier 55 is connected to the output voltage VB of the F/V conversion circuit 52.
is applied. The inverting input terminal is grounded via an amplification degree setting circuit 56. Negative feedback is applied to the operational amplifier 55 through a feedback resistor 57. The output voltage VC of the operational amplifier 55 is determined by the resistor 58
and is applied to the base of the transistor 54 via the Zener diode 59.

The output VA of the speed control signal generation circuit 30 is connected to the collector of the transistor 54 as a reverse control relay 67.
The signal is sent through the b contact 67b1. The amplification degree setting circuit 56 connects each a contact 21a2 of the first to fourth speed control relays 21 to 24 of the relay circuit 20 connected in parallel between the inverting input terminal of the operational amplifier 55 and the ground.
~24a2, each a contact 21a2~2
4a2 is a resistance R for setting the amplification degree for each vehicle speed range.
Variable resistance for adjusting each speed of 1st to R4 and 1st to 4th speed
The series circuits with VR are connected in series.

The resistance values of the amplification degree setting resistors R1 to R4 are the first
The speed amplification setting resistor R1 is the smallest, and the second
Resistors R2, R for setting the amplification degree of speed, 3rd speed, and 4th speed
3 and R4 increase in order. Therefore, the amplification degree of the amplifier circuit 53 is maximum when the first speed a contact 21a2 is turned on, and the amplification degree of the amplifier circuit 53 is maximum when the first speed a contact 21a2 is turned on.
The on-state of the fourth speed a contacts 22a2, 23a2, and 24a2 decreases in the order of on.

FIG. 3 shows the output voltage VB [V] of the F/V conversion circuit 52 and the frequency [Hz] of the output signal of the rotational speed detector 51 (velocity v [Km/h] of the unmanned vehicle) and the output voltage VB [V] of the output signal of the rotation speed detector 51 for each vehicle speed range. Output voltage VC of amplifier circuit 53
[V] data is shown.

FIG. 4 shows the speed control signal generation circuit 30 with respect to the frequency [Hz] of the output signal of the rotation speed detector 51.
The data of the output voltage VA [V] is shown.

In Figures 3 and 4, VC1min~
VC4min and VA1min to VA4min are F/V conversions when each speed of the 1st to 4th speeds is adjusted to the minimum value within each speed range by zeroing the resistance value of the speed adjustment variable resistor VR. Output voltage of circuit 52
Output voltage of VC and speed control signal generation circuit 30
It represents VA.

Also, VC1max~VC4max and VA1max~
VA4max is the VC and VA when each speed of 1st to 4th speed is adjusted to the maximum value within each speed range by setting the resistance value of variable resistor VR to the maximum value.
It represents.

When the rotational speed of the travel drive motor 2 increases,
Since the frequency of the output signal of the rotation speed detector 51 becomes higher and the output voltage VB of the F/V conversion circuit 52 becomes larger, the output voltage VC of the operational amplifier 55 also becomes larger. In this case, the higher the vehicle speed range is set among the first to fourth speeds, the lower the amplification degree of the amplifier circuit 53 is, so that VC becomes smaller as the designated vehicle speed range becomes larger.

When the output voltage VC of the operational amplifier 55 is less than the breakdown voltage of the Zener diode 59, no current flows through the base of the transistor 54, but the voltage VC
exceeds the breakdown voltage, a current flows through the base of transistor 54, and this base current
becomes larger as it becomes larger.

Since the collector current of the transistor 54 increases almost in proportion to the base current, as the voltage VC increases, the collector current increases and the voltage drop due to the output resistors 38 and 39 of the speed control signal generation circuit 30 increases. Therefore, the output voltage VA of the speed control signal generation circuit 30 decreases.

The output voltage VA is maintained at a constant voltage when the number of rotations of the drive motor 2 reaches a number of rotations corresponding to a specified speed (speed in a specified vehicle speed range). The larger the vehicle speed range, the smaller the voltage VC for the same rotational speed of the drive motor 2, so the output voltage VA settles to a larger value as the vehicle speed range becomes larger. In other words, the greater the vehicle speed register, the greater the vehicle speed is controlled.

When the vehicle speed becomes smaller than the specified speed after the vehicle speed reaches the specified speed, the voltage VC decreases, the voltage VA increases, and the duty ratio of the pulse signal output from the pulse generation circuit 42 of the motor control circuit 40 increases. The conduction rate of the transistor 4 increases, the motor drive current increases, and the vehicle speed increases.

Conversely, when the vehicle speed becomes higher than the specified speed, the voltage
As VC increases, voltage VA decreases, motor drive current decreases, and vehicle speed decreases. In other words, the vehicle speed is automatically controlled to reach the specified speed.

The drive current of the drive motor 2 is limited by an overload prevention current limitation circuit 80, a reverse braking current limitation circuit 90, and an overheat prevention current limitation circuit 100.

The overload prevention current limiting circuit 80 limits the drive current in the event of an overload, and is a current detector 81 that detects the drive current of the drive motor 2, and amplifies the detection output of the current detector 81 at a required amplification degree. and a transistor 83 that controls the output voltage VA of the speed control signal generation circuit 30 based on the output of the amplification circuit 82.

The output of amplifier circuit 82 is sent to the base of transistor 83 via resistor 84, diode 85, and Zener diode 86. Amplification circuit 8
The amplification degree of 2 means that when the detected current of the current detector 81 exceeds the reference current for overload detection, the amplification circuit 82
The output voltage of the Zener diode 86 is set to exceed the breakdown voltage of the Zener diode 86.

The collector of the transistor 83 is connected to the output side of the speed control signal generation circuit 30 via the b contact 67b1 of the reverse braking control relay 67.

When the load on the drive motor 2 increases and the drive current exceeds the reference current for overload detection, a current flows to the base of the transistor 83, and a collector current flows. Then, the voltage drop due to the output resistors 38 and 39 of the speed control signal generation circuit 30 increases, and the output voltage of the speed control signal generation circuit 30 decreases. Then,
Pulse generation circuit 42 of transistor drive circuit 40
The duty ratio of the pulse signal output from the transistor 4 becomes smaller, the conduction rate of the transistor 4 becomes smaller, and the motor drive current decreases. As a result, the drive current during overload is limited.

The reverse braking current control circuit 90 limits the drive current during reverse braking, and like the overload prevention current limiting circuit 80 described above, it includes a current detector 81,
It includes an amplifier circuit 91 and a transistor 92.

The current detector 81 is also used in the overload prevention current limiting circuit 80. The output of amplifier circuit 91 is sent to the base of transistor 92 via resistor 93 and Zener diode 94. The collector of the transistor 92 is connected to the output side of the reference voltage generation circuit 30 via the a contact 67a of the reverse braking control relay 67. transistor 9
The connection point between the base of No. 2 and the Zener diode 94 is grounded via the a contact 25a of the emergency stop control relay 25.

The reverse braking current control circuit 90 is provided to reduce the motor drive current, that is, the braking force during reverse braking, to soften the impact during braking. Therefore, the motor drive current during braking that should be adjusted is naturally smaller than the overload detection current, so the amplifier circuit 91 is designed to operate at a lower motor drive current than the overload prevention current limiting circuit 80. Amplification degree is 80 current limit circuit for overload prevention
It is set larger than that of the amplifier circuit 82.

The overheat prevention current limiting circuit 100 is provided to prevent the transistor 3 from overheating by reducing the drive current flowing through the transistor 4 when the heat generation temperature of the motor drive voltage control transistor 4 becomes high. Yes, there is a temperature detector 1 that detects the heat generation temperature of the motor drive current control transistor 4.
01 and an amplifier circuit 102 that amplifies the detection outputs of the temperature detector 101. Then, the output of the amplifier circuit 102 is connected to the resistor 103 and the diode 1.
04 to the Zener diode 86 of the overload prevention current limiting circuit 80.

When the heat generation temperature of the motor drive current control transistor 4 becomes high, the transistor 83 is turned on.
The output voltage VA of the speed control signal generation circuit 30 decreases, and the conduction rate of the motor drive current control transistor 4 decreases, so the drive current decreases and the heat generation temperature of the transistor 4 decreases.

The travel control device is provided with an automatic plugging circuit in order to decelerate the unmanned vehicle to the designated speed in a short time when a vehicle speed that significantly reduces the vehicle speed is designated.

The automatic plucking circuit 60 detects a large deceleration setting when the designated speed is significantly smaller than the current traveling speed, for example, when the ratio of the designated speed to the current traveling speed is 1/3 or less. It is comprised of a circuit 60-1 and a reverse rotation signal output circuit 60-2 that outputs a drive motor reverse rotation signal based on the detection output of the large deceleration setting detection circuit 60-1.

The large deceleration setting detection circuit 60-1 includes a resistor 63 that divides the output voltage VC of the amplifier circuit 53 of the speed control circuit 50, an operational amplifier 64 that outputs the divided voltage, and an operational amplifier 64 that detects the large deceleration setting. It consists of a Schmitt circuit 65 that outputs a detection signal when the reference voltage VO2 is exceeded.

The reversal signal output circuit 60-2 is driven by a relay driver 66 and a relay driver operated by a detection signal output from the Schmitt circuit 65, and switches the connection of the excitation winding 3a of the excitation circuit 3. Reverse braking control relay 67 for
It is equipped with

A backflow prevention diode 68 and an indicator light (light emitting diode) 69 are connected to the relay 67 . When the vehicle speed range is switched to a lower range, the output voltage VC of the amplifier circuit 53 of the speed control circuit 50 increases rapidly because the degree of amplification of the amplifier circuit 53 increases rapidly due to this switching. Furthermore, the larger the designated speed difference, the larger the voltage VC at this time. Voltage VC is resistor 63
The divided voltage is output from the operational amplifier 64, and this output voltage is sent to the Schmitt circuit 65.

In this embodiment, the reference voltage VO2 for detecting the large deceleration setting changes from a state in which the unmanned vehicle is running at the specified speed of 4th speed to 1st speed, and from a state in which it is running at the specified speed of 3rd speed. The value is set so that a large deceleration setting can be detected when the vehicle speed range is switched to the first speed. Therefore, the output voltage of the operational amplifier 64 changes to the reference voltage VO2 when the vehicle speed range is changed from the state of running in the fourth gear to the state of running in the first or third gear to the first gear. The Schmitt circuit 65 outputs a detection signal. When this detection signal is output, the output of the relay driver 66 becomes L level, the operating current is applied to the relay 67, and the indicator light 6
9 lights up.

When the relay 67 is activated, the forward rotation selector switch 3f of the excitation circuit 3 is turned off, and the reverse rotation selector switch 3f is turned off.
r is turned on, and the drive motor 2 rotates in reverse. In addition, due to the operation of the relay 67, its a contact 67b1 is turned off, and the current limiting circuit 80 for overload prevention, the current limiting circuit 100 for overheating prevention, and the speed control circuit 50
The runaway prevention circuit 70, which will be described later, is separated from the speed control signal generation circuit 30, and the a
Contact 67a is turned on, and reverse braking current limiting circuit 90 is connected to speed control signal generating circuit 30.

Therefore, the drive motor 2 is reversely braked by the motor drive current limited by the reverse brake current limiting circuit 90, and is quickly decelerated.
Then, when the vehicle speed is decelerated to around the specified speed, that is, when the rotational speed of the drive motor 2 decreases, the voltage VC decreases and the output voltage of the operational amplifier 64 becomes equal to or lower than the reference voltage VO2, so that the relay 67 is energized. is stopped, and the forward rotation changeover and reverse rotation changeover switches 3f and 3r of the excitation circuit 3 are returned to their original states.

Further, the a contact 67a of the relay 67 is turned off, and the reverse braking current limiting circuit 90 is disconnected from the speed control signal generation circuit 30, and the relay 67
The b contact 67b1 is turned on, and the overload prevention and overheat prevention current limiting circuits 80, 100, the vehicle speed control circuit 50, and the runaway prevention circuit 70 are connected to the speed control signal generation circuit 30 again.

The travel control device has an emergency stop function.
When it is desired to urgently stop an unmanned vehicle running in the third or fourth speed, a voltage is applied to the emergency stop command input terminal I5 of the relay circuit 20 using a manual switch. Then, the operation of the third speed or fourth speed control relays 23, 24 that had been activated is stopped, and the first speed control relay 21 and the emergency stop relay 25 are activated.

Then, the amplification degree setting circuit 5 of the speed control circuit 50
A contact 21 of the first speed control relay 21 at 6
a2 is turned on and the amplification degree increases rapidly, so the output voltage VC of the amplifier circuit 53 increases rapidly,
The output voltage of the operational amplifier 64 of the automatic planking circuit 60 exceeds the reference voltage VO2, and the reverse braking control relay 67 is activated to apply reverse braking.

The motor drive current during reverse braking is controlled by the reverse braking current limiting circuit 90, and the a contact 25a in the reverse braking current limiting circuit 90 is turned on due to the operation of the emergency stop relay 25. Since the output of the amplifier circuit 91 is sent to the ground side, no current is sent to the base of the transistor 92. Therefore, since the output voltage VA of the speed control signal generation circuit 30 becomes the reference voltage VO1, the drive motor 2 is reversely braked with a large drive current. As a result, the unmanned vehicle is rapidly decelerated.

When the unmanned vehicle is decelerated, the operation of the reverse braking control relay 67 is stopped, and the b of the relay 67 connected to the emergency stop command input terminal I5 of the relay circuit 20 is stopped.
Since the contact 67b2 is turned on, this contact 67b
A detection signal is output via 2. Based on this detection signal, the drive motor 2 and the DC power supply 1 are cut off, and the unmanned vehicle stops.

When a failure occurs in the speed control circuit 50 and the output voltage VB of the F/V conversion circuit 52 becomes zero, the output voltage VA of the speed control signal generation circuit 30 becomes the reference voltage.
It will rise to around VO1, so if you leave it as it is, the unmanned vehicle will go out of control. Therefore, this travel control device is provided with a runaway prevention circuit.

The runaway prevention circuit 70 includes the speed control signal generation circuit 3
The speed control circuit 70-1 detects that speed control by the speed control circuit 50 is disabled based on the output of 0, and the speed control circuit 70-1 detects that the speed control circuit 50 is unable to perform speed control. It is comprised of a voltage reduction circuit 70-2 that reduces the output voltage VA of the signal generation circuit 30.

The speed control failure detection circuit 70-1 receives the output voltage VA of the speed control signal generation circuit 30 sent via the b contact 67b1 of the reverse braking control relay 67.
A variable resistor 73 for dividing the voltage, a delay circuit 74 for outputting the divided voltage with a time delay, an output voltage VD of the delay circuit 74 and an output voltage VB of the F/V conversion circuit 52 of the speed control circuit 50. difference (VD
-VB) component, an operational amplifier 76 for accurately detecting the output voltage of the differential amplifier circuit 75, and when the output voltage of the operational amplifier 76 exceeds the speed control failure detection reference voltage VO3. It consists of a Schmitt circuit 77 that outputs a detection signal to.

The delay circuit 74 controls the F/F of the speed control circuit 50 with respect to the output voltage VA of the speed control signal generation circuit 30.
Since the output voltage VB of the V conversion circuit 52 has a time delay, this is to send the output voltage VA by the time delay of the output voltage VB. It consists of a connected diode 74c.

The voltage reduction circuit 70-2 includes two photo couplers PC1, PC2 and a photo coupler drive circuit 7.
It has 8. Both photo couplers PC1, PC2
An operating voltage is applied to the anode of the light emitting diode through a current control resistor 79, and the cathode is connected to the output side of the drive circuit 78.

The emitter of the photo transistor of one photo coupler PC1 is grounded, and the input voltage of the operational amplifier 32 of the speed control signal generation circuit 30 is applied to the collector. A speed control signal generation circuit 3 is connected to the collector of this photo transistor PC1.
An output voltage VA of 0 may be applied.

The emitter of the other photo transistor is connected to the alarm buzzer BZ, and the collector is connected to each vehicle speed range control relay 21 of the speed control signal generation circuit 30.
A buzzer drive voltage is applied through the a-contacts 21a1 to 24a1.

The reference voltage VO3 for speed control failure detection is such that the difference between voltages VA and VB is approximately equal to the reference voltage VO in order to detect speed control failure due to a failure in the speed control circuit 50.
The output voltage of the operational amplifier 76 is set to a value that exceeds the reference voltage VO3 when the voltage increases to be equal to 1.

When speed control is impossible, the output voltage VB of the F/V conversion circuit 52 becomes zero and the speed control signal generation circuit 3
Since the output voltage VA of 0 becomes the reference voltage VO1, the output voltage VD of the delay circuit 74 is determined by the difference (VD
-VB) increases, the output voltage of the differential amplifier 75 exceeds the speed control failure detection reference voltage VO3,
A detection signal is output from the Schmitt circuit 77.

When this detection signal is input to the drive circuit 78, the output of the drive circuit 78 becomes L level, current flows through the light emitting diodes of both photo couplers PC1 and PC2, and light is emitted, so that the photo transistors are turned on. Then, the input voltage of the operational amplifier 32 of the speed control signal generation circuit 30 is sent to the ground side through the photo transistor of the photo coupler PC1, so the output voltage of the operational amplifier 32 becomes zero, that is, the output of the speed control signal generation circuit 30. The voltage VA becomes zero and the unmanned vehicle is decelerated.

Also, the photo coupler PC2's photo
An operating voltage is applied to the buzzer BZ through the transistor, and the buzzer BZ is activated. When the unmanned vehicle is decelerated, the output voltage of the differential amplifier 75 becomes the reference voltage VO.
When it becomes 3 or less, the operation of photo couplers PC1 and PC2 is stopped, and the unmanned vehicle is accelerated again.
Therefore, the unmanned vehicle repeats acceleration and deceleration.

The speed control failure detection circuit 70-1 detects speed control failure when the output voltage VA of the speed control signal generation circuit 30 exceeds a value slightly lower than the reference voltage VO1, for example, 5.7V when the reference voltage is 6V. may be detected.

In this case, it is not necessary to provide the differential amplifier circuit 75, and the delay circuit 74 is also not necessary. It is also possible to detect the inability to control the speed due to a failure of the amplifier circuit 53 of the speed control circuit 50.

Photo coupler PC1 of voltage reduction circuit 70-2,
Diodes can also be used instead of PC2. That is, between the operating power supply of the buzzer BZ and the output terminal of the photo coupler drive circuit 78,
Connect the series circuit of buzzer BZ and diode,
A diode may be connected between the output side of the speed control signal generation circuit 78 and the output terminal of the photocoupler drive circuit 78. In this case, it goes without saying that both diodes are connected such that their cathodes are located on the output terminal side of the drive circuit 78.

[Brief explanation of drawings]

Figure 1 is an electric circuit diagram of the travel control device, Figure 2 is a graph showing the rise characteristics of the output voltage of the speed control signal generation circuit, and Figure 3 is the F/V conversion circuit for the frequency of the output signal of the rotational speed detector. FIG. 4 is a graph showing the output voltage of the speed control signal generating circuit with respect to the frequency of the output signal of the rotational speed detector. 2... Travel drive motor, 30... Speed control signal generation circuit, 40... Motor control circuit, 50... Vehicle speed control circuit, 51... Rotation speed detector, 52...
F/V conversion circuit, 70... Runaway prevention circuit, 70-
1... Speed control failure detection circuit, 70-2... Voltage drop circuit.

Claims (1)

[Scope of claims for utility model registration] (1) Speed control signal generation circuit 30 and vehicle speed control circuit 5
0 and a runaway prevention circuit 70, the speed control signal generation circuit 30 is controlled by the output signals of the vehicle speed control circuit 50 and the runaway prevention circuit 70, and corresponds to a vehicle speed range. The vehicle speed control circuit 50 generates a signal voltage corresponding to the rotational speed of the travel drive motor 2 detected by the rotational speed detector 51 and controls the motor control circuit 40 with its output. The runaway prevention circuit 70 includes a speed control failure detection circuit 70-1 and a voltage drop circuit 70-2, and a speed control signal corresponding to the vehicle speed range. The failure detection circuit 70-1 receives a voltage signal corresponding to the rotational speed of the vehicle speed control circuit 50 and an output voltage signal of the speed control signal generation circuit 30, and detects a failure of the vehicle speed control circuit 50 from the difference between them. The voltage reduction circuit 70-2 receives the failure detection signal and generates and outputs a signal that reduces the output voltage of the speed control signal generation circuit 30. A driving control device for an unmanned vehicle. (2) The runaway prevention circuit 70 is a voltage drop circuit 70-2.
2. The driving control device for an unmanned vehicle according to claim 1, which includes an alarm device BZ that is activated when the failure detection signal is input to the vehicle.