JPH0255255B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a braking control device for an unmanned electric vehicle, and in particular to an unmanned electric vehicle that performs braking control such as emergency stop of an electric vehicle traveling along a taxiway by cooperative operation of a hydraulic brake and an electromagnetic brake. It relates to a braking control device for a vehicle.

While this type of unmanned electric vehicle is traveling along a taxiway, various sensors installed on the electric vehicle detect when the electric vehicle deviates from the taxiway (off course) or an obstacle on the taxiway is detected. must be stopped. In general, braking of such unmanned electric vehicles is performed by the cooperative operation of hydraulic brakes that brake the wheels and electromagnetic brakes attached to the travel drive electric motor, but conventionally, a normal stop and an emergency stop as described above have been distinguished. Instead, if there was a stop command, the hydraulic brake and electromagnetic brake were operated simultaneously as shown in FIGS. 1A and B, and as long as the stop command continued, these two brakes remained in operation. For this reason, the braking state continues even after the necessary stopping state is secured, resulting in wasted braking energy that keeps each brake in the operating state, and in particular, repeated sudden activation of the electromagnetic brake In addition, there were various problems such as shortening the service life of the hydraulic brake, and continuing to apply the hydraulic brake to the hydraulic motor overheating the hydraulic motor.

The present invention has been made in view of the above points, and eliminates wasted braking energy, extends the life of the electromagnetic brake, eliminates overheating of the hydraulic motor, and is unmanned so that the operator can easily see the failure location during an emergency stop. The purpose is to provide a braking control device for electric vehicles. In order to achieve this object, in the present invention, a braking timing control means including a timer relay or the like that operates the electromagnetic brake after a predetermined operation delay time td after the activation of the hydraulic brake is provided in the drive control circuit of the hydraulic brake and the electromagnetic brake,
The braking timing control means is operated in response to a normal stop command from the outside, and the first operation delay time td ₁ is set.
The emergency stop device controls the hydraulic/electromagnetic brake drive circuit and performs an emergency stop sequence in response to the detection output of a sensor circuit installed in the running condition monitoring section of the electric vehicle that includes a failure point display section. The stop command causes the braking timing control means to operate, and controls the hydraulic/electromagnetic brake drive circuit at a second operation delay time td ₂ that is shorter than the first operation delay time td ₁ . Accordingly, the hydraulic brake is released again after a predetermined time period exceeding the second operation delay time _td2 has elapsed.

Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 2 is a block diagram showing the basic configuration of braking control for an unmanned electric vehicle according to the present invention. 10 is a hydraulic electromagnetic brake drive control circuit for driving and controlling a hydraulic brake (not shown) and an electromagnetic brake (not shown). In this drive control circuit 10, as shown in FIGS. 3A and _3B , the electromagnetic brake is activated at time t= _t2 after a predetermined operation delay time td from the activation of the hydraulic brake at time t=t1. Time t
= Release the hydraulic brake again at t ₃ (in this case,
The application time of the hydraulic brake is tb) A brake timing control means 12 including a timer relay and the like, and an emergency stop device 14 that performs an emergency stop sequence operation in response to a detection output of a sensor circuit to be described later are provided. The braking timing control means 1 is based on an external normal stop command fn or an emergency stop command fi from an emergency stop device 14 that responds to the output of a sensor circuit.
2, the hydraulic electromagnetic brake drive control circuit 10 is controlled so that the operation delay time td is shorter during an emergency stop than during a normal stop.

16 is a running state monitoring section, and this running state monitoring section 16 includes a sensor circuit 18 for detecting various running states of the electric vehicle;
Based on the latch circuit 20L that latches the detection output from the latch circuit 20L and the latch output of the latch circuit 20L,
Sensor circuit operation display unit 20 including a sensor operation display circuit 20D that drives a predetermined display tube such as an LED
and a latch circuit malfunction prevention circuit 22 for preventing malfunction of the latch circuit 20L. The sensor circuit 18 described above includes a rear obstacle sensor 18a, a relay welding detection circuit 18b, a course out detection circuit 18c, a signal abnormality detection circuit 18d, and an overspeed detection circuit 18.
e, safety bumper sensor 18f, side sensor 1
8g etc. are provided.

FIG. 4 shows an example of the internal circuit of the hydraulic/electromagnetic brake drive control circuit 10 shown in FIG. 2, which includes the braking timing control means 12 consisting of a timer relay, etc., and FIG. 5 similarly shows the hydraulic electromagnetic brake drive control circuit 10 shown in FIG. Examples of internal circuits of an emergency stop device 14 constituting the circuit 10, a sensor circuit 18, a latch circuit 20, a latch circuit malfunction prevention circuit 22, and a sensor circuit operation display section 24 constituting the driving state monitoring section 16 are shown.

First, referring to FIG. 4, 26 indicates a normal brake application circuit, which consists of three transistors.
It consists of Tr ₁ , Tr ₂ , Tr ₃ and the excitation coil 26L of the relay for applying the brake during normal braking.
Normal stop command given from the terminal of CPU28
fn is applied to the base of transistor _Tr3 . Further, 30 indicates an emergency brake application circuit, which is composed of transistors Tr ₄ , Tr ₅ , a thyristor SCR ₁ , and an excitation coil 30L of a relay for applying a brake during emergency braking, and the terminal A 1 is connected to the terminal A ₁ shown in FIG. 5, which will be described later. It is connected to the corresponding terminal A ₁ of the emergency stop device 14 . Also,
26C is the excitation coil 2 for the normal brake described above.
When the excitation coil 26L is energized by the 6L switching contact,
In other words, when the brake is off, terminal A ₁ is connected as shown by the dotted line.
When the excitation coil 26L is not energized, that is, when the brake is applied, it is connected to the terminal _b1 end as shown by the solid line. Similarly 30C
is a switching contact for the excitation coil 30L for the emergency brake described above, and is configured to be connected to terminal a ₂ when the brake is off and to terminal b ₂ when the brake is applied. Further, 32 is a hydraulic brake solenoid for operating a hydraulic brake; 34
is an electromagnetic brake solenoid for operating an electromagnetic brake. Furthermore, 36L is the excitation coil of the timer for electromagnetic brake application delay time during normal braking, 40L is the excitation coil for the timer for electromagnetic brake application delay time during emergency braking, and 38L is the timer for hydraulic brake release delay time after stopping the electric vehicle. This is the excitation coil. Also, 36C is the excitation coil 3
6L is a normally open contact, 38C is a normally open contact of exciting coil 38L, and 40C is a normally closed contact of exciting coil 40L.

Next, referring to FIG. 5, the emergency stop device 14
is for multiple digital devices such as gates and inverters.
IC IC _1-1 , IC _1-2 , IC _2-1 , IC _2-2 , IC _3-1 , IC _3-2 ,
IC _3-3 , IC _3-4 , IC _4-1 , IC _4-2 and transistor
It consists of Tr ₆ , Tr _7, etc., and the terminal A ₁ is the terminal of the emergency brake application circuit 30 in FIG. 4, as described above.
Connected to _A1 . In addition, latch circuit 20R
and a display section 2 including a sensor circuit operation display circuit 20D.
0 latches each detection output of the sensor circuits 18a to 18j, and in order to display the corresponding operation, thyristors SCR ₁₁ to _{SCR 17} corresponding to each sensor input whose anode side is connected to each indicator and this thyristor Gate control transistor Tr ₁₁ ~
It consists of Tr ₁₅ etc. The latch circuit malfunction prevention circuit 22 includes digital ICs, IC _5-1 , IC _5-2 , resistors R _5-1 to R _5-3 and a capacitor C ₅ for providing a predetermined time constant, and the input side is connected to the power supply. Potential V _DD (5V)
The output side is connected to the display section 2 mentioned above.
0 power supply.

One embodiment of the present invention is configured as described above, and its operation will be described next.

First, when the power is turned on, the rise of the power supply potential V _DD is delayed by a time constant based on the resistors R _5-1 to R _5-3 and the capacitor C ₅ of the latch circuit malfunction prevention circuit 22. That is, each IC _{5-1 ,}
The output of IC _5-2 is "L", and after a predetermined period of time, the output is reversed to "H" and the power supply potential of the display section 20 is
V _DD , which prevents the latch circuit from malfunctioning when the power is turned on.

Now, let us assume that a running electric car is brought to a normal stop. In the following explanation, it is assumed that the brake is not applied when each relay coil is in an energized state, but is applied in a non-excited state. When the normal stop command fn is given from the terminal of the CPU 28 shown in FIG. 4, the transistor Tr ₃ is turned on, and therefore the transistor Tr _{2 is} turned on.
turns on, transistor _Tr1 turns off.
For this reason, the excitation coil 26L for applying the brake during normal operation is in a non-excited state, so the corresponding contact 2
6C is switched and connected to terminal _b1 . As a result, the excitation coils 36L and 32L of the timer relay start operating. At this time, the excitation coil 30L for applying the brake in an emergency is in an excited state, so the contact 30C
is connected to terminal _a1 . Therefore, the excitation solenoid coil 32 for applying the hydraulic brake is in a non-excited state, and the hydraulic brake is applied as shown at time t= _t1 in FIG.

Next, the excitation coil 36L for timer T ₁ is activated at t=t ₂ in FIG. 3 after a predetermined time (operation delay time td ₁ ) has elapsed.
, the contact 36C becomes energized.
is opened and the excitation coil 3 for applying the electromagnetic brake
4 is the non-excitation state, and the electromagnetic brake is applied.
Furthermore, at time t= _t3 in FIG. 3, the excitation coil 38L for the timer _T2 is in an excited state, and its contact 38C is closed, so that the diodes _D1 and _D2 are closed.
Solenoid coil 3 for applying hydraulic brake via
2 is energized and becomes excited, and the hydraulic brake is released.

Next, a case will be described in which a running electric vehicle is brought to an emergency stop. Sensor circuit 18 shown in FIG.
When at least one of 18a-18g is detected at , it is provided as a sensor input to the emergency stop device 14 shown in FIG. In response to this sensor input, the output of gate IC _1-1 (or IC _1-2 ) becomes OV, and the output of IC _2-1 becomes power supply potential V _DD . this
V _DD is inverted by inverters IC _3-1 , IC _4-1 , and IC _4-2, respectively, and as a result, the output of IC _4-2 becomes OV. this
As mentioned above, the output of IC _4-2 is via terminal _A1 ,
Since it is connected to the emergency brake application circuit 30 in Fig. 5, the base current of the transistor Tr ₅ is
It flows into IC _4-2 , and transistor Tr ₅ is turned off. When transistor Tr ₅ turns OFF, thyristor SCR ₁ fires, transistor Tr ₄ turns OFF, and excitation coil 30L for applying brake during emergency braking becomes de-energized, and its contact 30C
is switched and connected to terminal _B2 side. At this time contact 26C
is connected to terminal _A1 . b ₂ of this contact 30C
By switching to the side, the excitation coil 32 is de-energized and a hydraulic brake is applied.
At this time, excitation coil 38L for timers T ₂ and T ₃ ,
Since the excitation coil 40L for the timer _T3 is excited after the set time of each timer, the contact 40C thereof is opened. Therefore, the excitation coil 34 for applying the electromagnetic brake is in a non-excited state, and the electromagnetic brake is applied. After that, after the time set by timer T ₂ , the excitation coil 38L is excited, and the excitation coil 32 for applying the hydraulic brake is energized via the diodes D ₃ and D ₂ , so the excitation coil 32 is again excited and the hydraulic pressure is increased. Release brake application.

The above explanation was about the operation of the hydraulic pressure and electromagnetic brake, but next we will explain the operation of the sensor circuit operation display section 2.
The operation of 0 will be explained. When there is a sensor input from the sensor circuit 18 while the vehicle is running, this sensor input is also applied to the sensor circuit operation display section 20 shown in FIG. For example, when there is a sensor input from the course out sensor 18C, the transistor Tr ₁₁
Since it is OFF, thyristor SCR ₁₁ is fired,
A display tube such as an LED (not shown) connected to the anode of this thyristor SCR ₁₁ is driven to display a predetermined operation. When other sensor inputs are received, the corresponding thyristor is similarly fired to display the necessary operation.

As explained above, according to the present invention, the operation delay time from the start of braking by the hydraulic brake to the start of braking by the electromagnetic brake during normal stop and during emergency stop is made shorter in the latter than in the former. Since the braking timing control means is provided in the hydraulic/electromagnetic brake drive control circuit, the emergency electromagnetic brake is not applied in a short period of time, so the electromagnetic brake shoe is less damaged and its life can be extended. In addition, the hydraulic brake is re-released after applying the electromagnetic brake, so
The risk of overheating the hydraulic motor is avoided. Such braking control makes it possible to reduce wasted energy compared to the conventional method. In addition, since an operation display section for the sensor circuit is provided to issue an emergency stop command, the operator can be informed of where a failure or abnormality is currently occurring, making maintenance extremely easy.

[Brief explanation of the drawing]

1A and 1B are operation timing charts of a hydraulic brake and an electromagnetic brake, respectively, in a conventional braking device for an unmanned electric vehicle, and FIG. 2 is a block diagram showing the basic configuration of a braking device for an unmanned electric vehicle according to the present invention. 3A and 3B are operation timing charts of the hydraulic brake and electromagnetic brake, respectively, of the braking device shown in FIG. 2, and FIG. 4 is mainly a braking timing control means of the hydraulic/electromagnetic brake drive circuit shown in FIG. 2. FIG. 5 is an electric circuit diagram showing an example of the emergency stop device and running state monitoring section shown in FIG. 2. 10...Hydraulic/electromagnetic brake drive control circuit, 1
2...braking timing control means, 14...emergency stop device, 16...driving state monitoring section, 18...sensor circuit, 20...sensor circuit operation display section, 20L
... Latch circuit, 20D ... Sensor operation display drive circuit, 22 ... Latch circuit malfunction prevention circuit.

Claims (1)

[Scope of Claims] 1. A braking control device for an unmanned electric vehicle that performs braking control of an electric vehicle traveling along a taxiway by the cooperative action of a hydraulic brake that brakes the wheels and an electromagnetic brake attached to a traveling drive machine. , provided in the hydraulic electromagnetic brake drive control circuit, comprising a running state monitoring unit including a sensor circuit for detecting the running state of the electric vehicle, and a hydraulic electromagnetic brake drive control circuit for driving and controlling the hydraulic brake and the electromagnetic brake; An emergency stop device is provided that performs an emergency stop sequence operation in response to the detection output of the sensor circuit, and
a predetermined operation delay time from the activation of the hydraulic brake;
A braking timing control means for operating the electromagnetic brake after td is further provided in the hydraulic electromagnetic brake drive control circuit, and the braking timing control means operates based on a normal stop command from the outside to operate the electromagnetic brake at the first operation delay time td ₁ . The hydraulic electromagnetic brake drive control circuit is controlled, and the first operation delay time td is caused by the operation of the braking timing control means based on an emergency stop command from the emergency stop device that operates in response to the detection output of the sensor circuit. A braking control device for an unmanned electric vehicle, characterized in that the hydraulic electromagnetic brake drive control circuit is controlled with a second operation delay time _td2 shorter than ₁ . 2. Braking control for an unmanned electric vehicle according to claim 1, wherein the braking timing control means releases the hydraulic brake again after a predetermined time period exceeding the second operation delay time _td2 has elapsed. Device. 3. The driving state monitoring unit further includes a sensor circuit operation display unit including a latch circuit that latches the detection output of the sensor circuit, and a sensor operation display drive circuit that displays a predetermined display based on the output of the latch circuit. A braking control device for an unmanned electric vehicle according to claim 1 or 2, characterized in that: 4. The driving state monitoring unit further includes a latch circuit malfunction prevention circuit that puts the latch circuit into an inoperable state so that the latch circuit does not malfunction when the power is turned on. braking control device for unmanned electric vehicles. 5. The unmanned electric vehicle according to claim 1, wherein the sensor circuit is capable of detecting at least one of the deviation of the electric vehicle from the taxiway and the presence of an obstacle on the taxiway. brake control device. 6. The braking control device for an unmanned electric vehicle according to claim 1, wherein the braking timing control means includes a timer having different time limits corresponding to the first and second operation delay times.