JPS6246747A - Vehicle brake control device - Google Patents

Abstract

PURPOSE:To improve stopping accuracy of a vehicle such as an unmanned forklift by changing braking time of a hydraulic brake in accordance with the running speed when a stop signal is inputted and by actuating a magnetic brake after the vehicle has run for a specified stopping distance. CONSTITUTION:When an unmanned vehicle runs along a track and a pattern sensor 1 senses a stop mark plate, a central processing unit 7, after sending a control signal for stopping power supply of a running motor 5 to a motor drive circuit 10, performs normal stop control processing action. Namely, while the stopping distance from the time point when the stop command was generated is calculated from the output from an rpm sensor 4, the running speed at that time point is calculated. Then a solenoid valve 14 is switched to actuate a hydraulic brake 15 to begin braking. After running for a stopping distance read out in accordance with the running speed, the braking is released. And at a time point when the distanced travelled till then reaches the specified standard stopping distance, a magnetic brake 12 is actuated to stop the vehicle.

Description

[Detailed Description of the Invention] Object of the Invention (Industrial Application Field) The present invention relates to a brake control device for a vehicle, and specifically relates to a brake control full device that controls the stopping distance from the start of braking to the stop. .

(Prior Art) Conventionally, unmanned forklifts are equipped with two types of braking devices: a hydraulic brake and an electromagnetic brake provided adjacent to the travel motor. The reason why these two different braking devices are installed is that when the electromagnetic brake is used during braking, the electromagnetic brake stops and locks the drive shaft of the travel motor, so the braking horn is directly added to the drive system between the motor and the wheels and drives the motor. Hydraulic brakes are used when braking, as there is a risk of twisting and damaging the shaft of the system.On the other hand, since hydraulic brakes are structurally incapable of working while the system is stopped, electromagnetic brakes should be used while the system is stopped. This was because it was used.

As a braking method, when a stop signal is received from a ground station, for example, the electromagnetic valve is immediately opened and the hydraulic brake is operated for a predetermined time t1 to perform braking, and at the same time, the electromagnetic brake is activated when the stop signal is received from the ground station. It is configured to operate after a predetermined time t2 after receiving the signal.

The operating time and timing of each brake are determined by counting the predetermined times tl and t2 by a timer that operates in response to the stop signal.

(Problem to be solved by the invention) However, since this fixed timer only determines one braking time and timing, that is, the operating time of the hydraulic brake is always constant. Therefore, there was a large variation in the stopping distance (distance #1 traveled by the vehicle from the start of braking to the time of stopping) depending on the speed of the vehicle immediately before the start of braking. Therefore, the stopping accuracy was very poor. Moreover, the electromagnetic brake also operates immediately after a predetermined period of time has passed, so if the Ila brake is applied when the hydraulic brake is not able to fully brake and the vehicle is still coasting with a large momentum, a large force will be applied to the drive system, which will drive the same drive system. Damage to each axis of the system could occur.

This invention solves the above problems by changing the braking time of the hydraulic brake depending on the traveling speed at the start of braking, and by always decelerating the coasting speed to a predetermined speed or less before applying the electromagnetic brake. To provide a brake control device for a vehicle that can always stop a vehicle reliably without damaging each member of a drive system using a predetermined stop button, and that has high stopping accuracy.

Structure of the Invention (Means for Solving Problems) In order to achieve the above object, the present invention provides a traveling distance calculating means for calculating the traveling distance of the vehicle and a traveling speed calculating means for calculating the traveling speed of the vehicle. Further, a hydraulic brake for applying hydraulic braking to the vehicle and a hydraulic brake drive means for driving the hydraulic brake are provided, and an electromagnetic brake for applying braking to the vehicle separately from the hydraulic brake is provided.

Furthermore, a storage means is provided for storing data on the braking time of the hydraulic brake with respect to the traveling speed calculated by the traveling speed calculating means.

Furthermore, input a stop signal to stop the vehicle,
A brake control means reads the braking time for the current traveling speed calculated by the traveling speed calculation means from the storage means and controls the hydraulic brake driving means to operate the hydraulic brake for the braking time; and an electromagnetic brake control means for determining whether the vehicle has reached a predetermined distance after inputting the stop signal and operating the electromagnetic brake when it is determined that the same distance has been reached. The gist of this article is the brake system for vehicles.

(Operation) The hydraulic brake control means stops the vehicle! When a stop signal is input to cause the vehicle to stop, the data on the braking time of the hydraulic brake for the current traveling speed calculated by the traveling speed calculation means is read from the storage means, and the hydraulic brake drive means is controlled for the braking time to activate the hydraulic brake. is activated to decelerate the vehicle to a predetermined speed. On the other hand, the electromagnetic brake control means inputs the stop signal and determines whether the vehicle has reached a predetermined travel distance (stopping distance) based on the calculation data of the travel distance calculation means. When it is determined that the distance traveled has been reached, the electromagnetic brake is activated to stop the vehicle.

(Embodiment) Hereinafter, an embodiment of a brake control device for an unmanned four-lift that embodies the present invention will be described with reference to the drawings.

Figure 1 shows the vehicle traveling along a track line laid on the ground, reading mark plates placed on the route, which can direct the movement of the gods by the arrangement and combination of these marks, and operating based on the arrangement of the mark plates. The pattern detection device 1 is a known detection device provided on the underside of the forklift, and each mark plate (not shown) arranged on the traveling path is shown in FIG. is detected and outputs the arrangement combination of the mark plates as an arrangement signal to the input/output interface 2 provided on the on-board station of the forklift.The optical sensor 3 is also provided on the underside of the forklift 1 and is placed at a predetermined location on the travel path. The receiver outputs an optical data signal from a provided light emitting element (not shown) to the input/output interface 2.The light emitting element receives various commands such as running commands and stop commands output from the control device of the ground station. A driving command signal is output to the optical sensor 3.

The rotation speed detection device 4 is a known detection device for detecting the rotation speed of a driving motor 5, which is a DC motor of a forklift, and includes a rotating plate attached to the drive shaft of the driving motor 5 and the rotating plate. The detection signal from the sensor is output to the input/output interface 2.

A microcomputer 6 installed in an on-board station of a forklift temporarily stores a central processing unit (hereinafter referred to as CPU) 7, a program memory 8 consisting of a read-only memory (ROM) that stores control programs, and results of arithmetic processing. Readable and replaceable memory (RAM)
The CPU 7 operates based on a control program stored in a program memory 8.

The CPU 7 inputs signals from the detection devices 1 and 4 and the sensor 3 via the interface 2. Then, the CPU 7 determines the arrangement combination of the mark plates detected by the pattern detection device 1 based on the arrangement signal from the pattern detection device 1, that is, what is the next operation command to be issued by the forklift from this mark plate position, Processing operations are executed to cause the forklift to operate based on the determined operation command. Similarly, the CPU 7 determines the contents of the optical data signal from the optical sensor 3, that is, the operation command signal from the ground station, and performs processing operations to cause the forklift to operate based on the determined operation command. Execute.

Further, the CPU 7 calculates the traveling speed V of the forklift at that time based on the detection signal from the rotation speed detection device 4, and calculates the traveling distance 11S of the forklift based on the same detection signal. Note that each calculation performed by the CPU 7 on this detection signal is performed based on data stored in the program memory 8 in advance.

On the other hand, the CPU 7 drives and controls the traveling motor 5 via a motor drive circuit 10 and controls the electromagnetic brake 12 via an electromagnetic brake drive circuit 11. The electromagnetic brake 12 is provided at a position adjacent to the traveling motor 5, and is configured not to brake the rotary motor 5 when energized, but to brake the motor 5 when not energized. . Further, the CPU 7 controls switching of the electromagnetic switching valve 14 via the valve drive circuit 13. The electromagnetic switching valve 14 is a valve that controls the supply of hydraulic oil to the hydraulic brake 15 of the forklift, and the operation of the hydraulic brake 15 is controlled based on the switching operation.

The program memory 8 stores data on the braking time T for operating the hydraulic brake 15 for each traveling speed V. In this embodiment, the braking time T for each traveling speed V is the operation fJ1 time of the hydraulic brake 15 when the hydraulic brake 15 is decelerated to a predetermined speed V1 for each traveling speed V of the forklift traveling with the maximum load capacity. Therefore, if the traveling speed (2) at the start of braking is large, the braking time T will be proportionally long. Note that the predetermined speed V1 is based on the reference stopping path 131 and the hydraulic brake 15, which will be described later.
and the braking force of the electromagnetic brake 12, and the traveling path il! of the forklift is determined by the braking force of the electromagnetic brake 12 at least when the speed is reduced to this speed V1! The iS does not reach the standard stopping distance S1 described later, and the electromagnetic brake 1
It is preset to a value that allows the forklift to be stopped without difficulty when braking is applied at step 2. Moreover,
When the loaded weight is small or zero, the CPU 7 selects the braking time corresponding to the current traveling speed at the maximum weight and performs braking.
will reach the predetermined speed V1 before the braking time T, but this braking time means that the running speed V does not reach zero until the same time T and the vehicle coasts until the reference stopping distance $1. We set the value as much as possible.

Next, the operation of the brake control device configured as described above will be explained.

Now, when the forklift is traveling along the track line to a mark plate that indicates the operation details for stopping the forklift placed on the travel path, the pattern detection device 1 installed on the forklift detects the mark plate. The detected array signal is sent to the CPU 7 via the interface 2.
Output to. The CPU 8 determines that this array signal is the operation content of a stop command to stop the forklift, outputs a control signal to the motor drive circuit 10 to cut off the supply of drive power to the travel motor 5, and then executes a normal stop control processing operation. do.

In the normal stop control processing operation, the CPU 7 starts calculating the travel distance S based on the detection signal from the rotation speed detection device 4 from the time when the CPU 7 determines that it is the stop command, that is, the mark plate detection position is the starting point. The contents are stored in the working memory 9, and the traveling speed V at the time when the stop command is determined is calculated and stored in the working memory 9 (step 1). Next, the CPU 7 operates the valve drive circuit 1 to operate the hydraulic brake 15 to apply braking, that is, to switch and operate the electromagnetic valve 14.
3 to output a drive control signal (step 2). At the same time, the CPU 7 reads out the braking time T for the calculated traveling speed V and stores it in the working memory 9 (
Step 3), a timer built into the CPU 7 is activated (step 4), and the hydraulic brake 15 is controlled to continue operating until the timer time t of the timer reaches the braking time T (step 5). Therefore, at this point, the forklift is braked by the hydraulic brake 15 and gradually decelerated.

Eventually, the timer time t of the timer of the CPU 7 becomes the braking time T.
In step 5), that is, in this embodiment, when the traveling speed V of the forklift 1- decelerates to a predetermined speed V1, the CPU 7 immediately sends a control signal to the valve drive circuit 13 to release the braking by the hydraulic brake 15. is output to switch the electromagnetic switching valve 14 (step 6). Therefore, from this point on, the brakes of the forklift are released and the forklift runs by coast.

Next, the CPU 7 calculates that the travel route l1IS up to that time, which has been sequentially calculated and rewritten and stored in the working memory 9, is a predetermined travel distance (hereinafter referred to as reference stop route #IS1).
It is determined whether the target value has been reached (step 7). Note that the reference stopping distance S1 is the distance at which the forklift is desired to be stopped from the point where the stop command is issued, and the data thereof is stored in the program memory 8 in advance.

Eventually, the travel distance S of the forklift reaches the reference stopping road l1.
When reaching llts1, the CPU 7 immediately outputs a control signal to the electromagnetic brake drive circuit 11 to stop the forklift at the distance S1, thereby changing the electromagnetic brake 12 from the energized state to the de-energized state (step 8). Therefore,
When the electromagnetic brake 12 is de-energized, the driving motor 5 is braked. As a result, the forklift is stopped at the reference stopping distance S1 by braking of the electromagnetic brake 12. At this time, since the traveling speed V is at least below the predetermined speed V1, even if the electromagnetic brake 12 is applied, no large load is applied to the drive system, and the forklift stops at the same time as the electromagnetic brake 12 is applied.

In addition, in this embodiment, the forklift stop control was explained using a stop command based on a mark plate, but the optical sensor 3 provided on the forklift was outputted from the control device of the ground station via a light emitting element provided on the travel path. When a stop command signal is input, the same stop control as described above is performed.

In this way, in this embodiment, when receiving a stop command,
A braking time T corresponding to the traveling speed at the time of receiving the stop command is selected, and the hydraulic brake 15 is applied for the selected braking time T.
is activated to decelerate the forklift, and when the forklift eventually reaches the standard stopping distance S1, the electromagnetic brake 12 is applied to stop the forklift. A large load is not applied to the shaft, etc., and the drive system can be protected when stopped. Furthermore, since the forklift can always be stopped at the reference stop +xsi, highly accurate operation control can be performed.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and may be applied to industrial vehicles other than unmanned forklifts, such as automatic guided vehicles, and the microcomputer 6 of the above-mentioned embodiments may be used to control each drive device for stop control. In addition to this, various devices necessary for operation and cargo handling work, such as a steering drive device that drives and controls the steering wheels and a cargo handling drive device that drives and controls cargo handling devices, are also controlled. May be implemented.

Effects of the Invention As detailed above, according to the present invention, the braking time of the hydraulic brake is changed depending on the traveling speed at the start of braking, so that the coasting speed before applying the electromagnetic brake is always at the predetermined speed. The vehicle is decelerated below the vehicle speed, and the vehicle can be reliably stopped within a predetermined stopping distance without damaging any components of the drive system, making it an extremely accurate vehicle brake control device. can do.

[Brief explanation of the drawing]

FIG. 1 is an electrical block circuit diagram of a brake device embodying the present invention, and FIG. 2 is a flowchart for explaining the operation of the brake device. In the figure, 1 is a pattern detection device, 3 is an optical sensor, 4 is a rotation speed detection device, 5 is a running motor, 6 is a microcomputer, 7 is a CPU, 8 is a program memory, 10 is a motor drive circuit, and 11 is an electromagnetic A brake drive circuit, 12 is an electromagnetic brake, 13 is a valve drive circuit, 14 is an electromagnetic switching valve, and 15 is a hydraulic brake.

Claims (1)

[Scope of Claims] 1. A mileage calculation means for calculating the mileage of the vehicle; a travel speed calculation means for calculating the travel speed of the vehicle; a hydraulic brake that brakes the vehicle with hydraulic pressure; A hydraulic brake driving means for driving the vehicle; a storage means for storing data on a braking time of the hydraulic brake with respect to the traveling speed calculated by the traveling speed calculating means; an electromagnetic brake that applies braking to the vehicle separately from the hydraulic brake; inputting a stop signal to stop the vehicle, reading the braking time for the current traveling speed calculated by the traveling speed calculation means from the storage means, and controlling the hydraulic brake driving means to operate the hydraulic brake for the braking time. a brake control means for inputting the stop signal, determining whether or not the vehicle has reached a predetermined travel distance after inputting the stop signal, and when determining that the vehicle has reached the predetermined travel distance; A vehicle brake control device comprising an electromagnetic brake control means for operating an electromagnetic brake. 2. The brake control device for a vehicle according to claim 1, wherein the electromagnetic brake is provided at a position adjacent to the travel motor and applies braking to the drive shaft of the motor.