JP2021160471A - Brake device and control method of brake device - Google Patents

Abstract

To effectively prevent a collision or contact with an obstacle by applying an appropriate brake force to a stopped vehicle according to a peripheral situation of the vehicle.SOLUTION: A brake device mounted on a vehicle is activated by a supply of a prescribed fluid pressure and can apply a brake force to wheels of the vehicle. The brake device comprises: a stop detection part 92 for detecting whether the vehicle has stopped; an obstacle determination part 110 for determining whether an obstacle which may collide or come in contact exists in a periphery of the vehicle; and a control part 130 which, when it is detected that the vehicle has stopped and it is determined that an obstacle exists, executes a start prevention control of preventing the vehicle from starting by maintaining the fluid pressure of the brake device at the fluid pressure when the vehicle has stopped.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a brake device and a control method of the brake device, and more particularly to a technique suitable for preventing an erroneous start of a vehicle.

For example, Patent Document 1 describes a vehicle technology equipped with a function of automatically controlling a braking device while the vehicle is running to apply a desired braking force to the wheels to maintain a distance from the preceding vehicle at a predetermined distance. Is disclosed.

Japanese Unexamined Patent Publication No. 2017-61323

For example, in a vehicle equipped with an automatic transmission, when the driver depresses the brake pedal to stop the vehicle and then releases the brake pedal, the vehicle starts slightly due to creep torque. In such a situation, for example, if an obstacle such as a pedestrian or another vehicle exists around the vehicle, there is a problem that the risk of collision or contact with the obstacle increases when the driver's judgment is delayed. be.

The technology of the present disclosure has been made in view of the above circumstances, and by applying an appropriate braking force to the vehicle according to the surrounding conditions of the stopped vehicle, collision or contact with an obstacle can be effectively performed. The purpose is to prevent it.

The device of the present disclosure is a braking device that is mounted on a vehicle and can be activated by supplying a predetermined fluid pressure to apply a braking force to the wheels of the vehicle, and determines whether the vehicle has stopped. When the stop detection means for detecting, the obstacle determination means for determining whether or not there is an obstacle that may collide with or come into contact with the vehicle around the vehicle, and the stop of the vehicle are detected. When it is determined that there is an obstacle, the control means for executing the start prevention control for preventing the vehicle from starting by holding the fluid pressure of the brake device at the fluid pressure when the vehicle is stopped. It is characterized by being prepared.

Further, it is preferable that the control means releases the start prevention control when it is determined by the obstacle determination means that the obstacle has disappeared after the start prevention control is executed.

Further, an accelerator opening detection means for detecting the accelerator opening according to the driver's depression of the accelerator pedal is further provided, and the control means executes the start prevention control and then uses the obstacle determination means to determine the obstacle. When it is determined that there is no more, and the accelerator opening degree is detected by the accelerator opening degree detecting means, it is preferable to release the start prevention control.

The method of the present disclosure is a control method of a braking device which is mounted on a vehicle and can be operated by supplying a predetermined fluid pressure to apply a braking force to the wheels of the vehicle, and the vehicle is stopped. It is determined whether or not there is an obstacle around the vehicle that may collide with or come into contact with the vehicle, and when the vehicle is stopped, it is determined that the obstacle is present. Then, by holding the fluid pressure of the brake device at the fluid pressure when the vehicle is stopped, the start prevention control for preventing the vehicle from starting is executed.

According to the technique of the present disclosure, it is possible to effectively prevent a collision or contact with an obstacle by applying an appropriate braking force to the vehicle according to the surrounding conditions of the stopped vehicle.

It is a schematic overall block diagram of the vehicle equipped with the brake device which concerns on this embodiment. It is a schematic functional block diagram which shows the control device which concerns on this embodiment, and the related peripheral configuration. It is a schematic timing chart figure which shows an example of the start prevention control which concerns on this embodiment. It is a flowchart explaining the process flow of the start prevention control which concerns on this embodiment. It is a flowchart explaining the process flow of the start prevention control which concerns on this embodiment.

Hereinafter, the brake device and the control method of the brake device according to the present embodiment will be described with reference to the accompanying drawings. The same parts have the same reference numerals, and their names and functions are also the same. Therefore, detailed explanations about them will not be repeated.

[overall structure]
FIG. 1 is a schematic overall configuration diagram of a vehicle 1 equipped with the brake device 30 according to the present embodiment.

The vehicle 1 is equipped with an engine 10 as an example of a driving force source. A transmission 13 is connected to the engine 10 via a fluid coupling 11, a clutch device 12, and the like. The left and right drive wheels (wheels of the present disclosure) 17L and 17R are connected to the transmission 13 via a propeller shaft 14, a differential gear 15, and drive shafts 16L and 16R, respectively. Further, left and right steering wheels (wheels of the present disclosure) 18L and 18R are provided on the front side of the vehicle 1.

The power transmission system of the vehicle 1 is not limited to the illustrated example, and may have other configurations. Further, the vehicle 1 is not limited to the rear-wheel drive vehicle, and may be a front-wheel drive vehicle, a four-wheel drive vehicle, or the like. Further, the vehicle 1 is not limited to the engine vehicle, and may be a hybrid vehicle including the engine 10 and the motor.

The transmission 13 is, for example, an automatic transmission, and the transmission is automatically changed according to the operation of the speed change operation device 20 provided in the driver's cab. Specifically, the speed change operation device 20 includes an operation lever 21 that can be selectively operated in the parking range P, the reverse range R, the neutral range N, the drive range D, and the like. When the operating lever 21 is selected for the drive range D, the transmission 13 is automatically changed to the optimum gear according to the traveling state of the vehicle 1. The transmission 13 may be either a stepped transmission or a continuously variable transmission. In the case of a continuously variable transmission, the clutch device 12 and the like may be omitted.

A parking brake device 19 capable of locking the rotation of the propeller shaft 14 is provided at the output side end of the transmission 13. The parking brake device 19 operates when the operating lever 21 is operated by the parking range P to lock the propeller shaft 14.

The brake device 30 is, for example, an air type brake device, and mainly includes an air tank 31, an air pipe 32, a brake valve 33, a brake chamber 34, and a brake 35.

The air tank 31 stores compressed air. The compressed air is supplied from, for example, a compressor 36 driven by the power of the engine 10. The air pipe 32 connects the air tank 31 and the brake chamber 34. The brake valve 33 is provided in the air pipe 32, and linearly controls the amount of compressed air supplied from the air tank 31 to the brake chamber 34.

When the driver depresses the brake pedal 40, the brake device 30 opens the brake valve 33 according to the depressing amount of the brake pedal 40, so that compressed air is supplied from the air tank 31 to the brake chamber 34. When compressed air is supplied to the brake chamber 34, the brake 35 operates according to the amount of compressed air supplied (brake pressure), so that desired braking force is applied to the wheels 17L, 17R, 18L, and 18R. It has become like. On the other hand, when the driver releases the depression of the brake pedal 40, the brake valve 33 closes, and the supply of compressed air is stopped accordingly, thereby imparting braking force to the wheels 17L, 17R, 18L, and 18R. Is to be released.

The vehicle 1 is provided with various sensors 91 to 97. The detection signals of these various sensors 90 to 97 are transmitted to the electrically connected control device 100.

The accelerator opening sensor 91 (accelerator opening detection means) detects the accelerator opening Ac according to the driver's depression of the accelerator pedal 41. The vehicle speed sensor 92 (an example of the vehicle stop detection means) detects the vehicle speed V of the vehicle 1 from the propeller shaft 14 and the like. The vehicle speed sensor 92 may be a wheel speed sensor.

The brake pressure sensor 93 is provided in the air pipe 32 and detects the pressure of the compressed air (hereinafter, referred to as the brake pressure P) supplied from the air tank 31 to the brake chamber 34. The brake pedal sensor 94 detects the amount of depression of the brake pedal 40 by the driver (hereinafter referred to as stroke amount S). The brake pedal sensor 94 may be a brake switch that detects ON / OFF of the brake. The shift position sensor 95 detects the operating position (range) of the operating lever 21 of the shifting operating device 20.

The front obstacle acquisition unit 96 is, for example, a camera that captures a front image of the vehicle 1, a millimeter wave radar, an ultrasonic sensor, a laser radar, or the like, and is a front obstacle such as a pedestrian or another vehicle in front of the vehicle 1. Obtain the presence and / or distance (relative distance) from these forward obstacles. The rear obstacle acquisition unit 97 is, for example, a camera for capturing a rear image of the vehicle 1, a millimeter wave radar, an ultrasonic sensor, a laser radar, or the like, and is a rear obstacle such as a pedestrian behind the vehicle 1 or another vehicle. The existence and the distance (relative distance) to these rear obstacles are acquired.

[Control device]
FIG. 2 is a schematic functional block diagram showing the control device 100 according to the present embodiment and related peripheral configurations.

The control device 100 is, for example, a device that performs calculations such as a computer, and is a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input port, and an output port connected to each other by a bus or the like. Etc., and execute the program.

Further, the control device 100 functions as a device including a front / rear obstacle determination unit 110 (obstacle determination means), a brake pressure storage unit 120, and a start prevention control unit 130 (control means) by executing a program. do. Each of these functional elements will be described as being included in the control device 100, which is integrated hardware in the present embodiment, but any part of these may be provided in separate hardware.

The front / rear obstacle determination unit 110 relates to the relative distance to the obstacle in front of the vehicle 1 transmitted from the front obstacle acquisition unit 96 and the obstacle behind the vehicle 1 transmitted from the rear obstacle acquisition unit 97. Based on the relative distance, it is determined whether or not there is an obstacle (pedestrian, other vehicle, etc.) that may collide or come into contact with the vehicle 1 in front of or behind the vehicle 1.

Specifically, the front / rear obstacle determination unit 110 has a possibility of collision or contact when the relative distance to the obstacle transmitted from each of the acquisition units 96 and 97 is less than a predetermined threshold distance. Determine that an object exists. On the other hand, the front / rear obstacle determination unit 110 determines that no obstacle exists when the relative distance to the obstacle transmitted from each of the acquisition units 96 and 97 is equal to or greater than a predetermined threshold distance. The determination result by the front / rear obstacle determination unit 110 is transmitted to the start prevention control unit 130 in real time. In the present disclosure, the term "front" includes the front right and the front left in addition to the front front of the vehicle 1. Further, the rear includes not only the rear front of the vehicle 1 but also the right rear and the left rear.

The brake pressure storage unit 120 is, for example, a non-volatile memory and stores the brake pressure P when the vehicle 1 is stopped. Specifically, in the brake pressure storage unit 120, when the brake pedal 40 is depressed while the vehicle 1 is running, the vehicle 1 is stopped accordingly, and then the stroke amount S of the brake pedal 40 reaches a predetermined value, the stroke amount S at that time is reached. The brake pressure P is stored as the _{holding brake pressure P_S.} Further, when the ignition switch is turned ON while the brake pedal 40 is depressed when the engine 10 is started, the brake pressure storage unit 120 stores the brake pressure P at that time as the holding brake pressure _{P_S} .

Here, whether or not the vehicle 1 has stopped may be detected based on the vehicle speed V acquired by the vehicle speed sensor 92. Further, the brake pressure P may be acquired by the brake pressure sensor 93, and the stroke amount S of the brake pedal 40 may be acquired by the brake pedal sensor 94.

When the start prevention control unit 130 determines that an obstacle exists by the front / rear obstacle determination unit 110, the start prevention control unit 130 applies the brake pressure P of the brake device 30 to the holding brake pressure _{P_S stored in the brake pressure storage unit 120.} By holding the vehicle 1, start prevention control for preventing erroneous start of the vehicle 1 is performed. Hereinafter, the details of the start prevention control will be described with reference to FIG.

FIG. 3 is a schematic timing chart showing an example of start prevention control when the speed change operation device 20 is selected for the drive range D or the reverse range R.

When the brake pedal 40 is depressed at time t1 while the vehicle 1 is traveling in the drive range D or the reverse range R, and the vehicle 1 stops at time t2, the brake pressure storage unit 120 holds the vehicle 1 at time t3. _{Stores the} brake pressure P_S.

Further, at time t3, it is determined whether or not there is a possibility of collision or contact with an obstacle. Specifically, (1) with the shift position sensor 95 detecting that the current range is the drive range D, the front / rear obstacle determination unit 110 determines that there is an obstacle in front of the vehicle 1. If, or (2) the shift position sensor 95 detects that the current range is the reverse range R, the front / rear obstacle determination unit 110 determines that there is an obstacle behind the vehicle 1. In this case, the start prevention control unit 130 transmits an instruction signal to the brake valve 33 so that the brake pressure P of the brake device 30 is held by the holding brake pressure _{P_S.} At this time, the opening degree of the brake valve 33 on the basis of the deviation between the brake pressure P and the holding brake pressure P _{_S} acquired by the brake pressure sensor 93, as the brake pressure P is maintained at the holding brake pressure P _{_S} Feedback control may be sufficient.

The start prevention control started from time t3 until the front / rear obstacle determination unit 110 determines that there are no obstacles at time t5 even if the driver releases the brake pedal 40 at time t4. During that time, it will continue to be implemented. When it is determined at time t5 that there are no obstacles, the start prevention control is terminated by releasing the braking force of the brake device 30 (closing the brake valve 33).

In this way, when it is determined that there is an obstacle in front of or behind the vehicle 1 when the vehicle 1 is stopped, the start prevention control for holding the _{brake pressure P at the holding brake pressure P_S is executed.} It becomes possible to prevent the vehicle 1 from erroneously starting due to the driver's careless accelerator operation, creep torque, or the like. This makes it possible to effectively prevent collisions and contact with obstacles in front of and behind the vehicle 1.

Next, the flow of the start prevention control process according to the present embodiment will be described based on the flowcharts of FIGS. 4 and 5.

FIG. 4 is a flow chart of start prevention control when the engine 10 is started and the vehicle 1 is started.

In step S100, it is determined whether or not the brake pedal 40 is depressed and the ignition switch is turned on. When the brake pedal 40 is depressed and the ignition switch is turned ON (Yes), this control proceeds to step S110. On the other hand, if neither of the conditions is satisfied (No), this control is returned.

In step S110, the holding brake pressure _{P_S} is stored in the brake pressure storage unit 120. Next, in step S120, it is determined whether or not the speed change operating device 20 is selected from the parking range P to the drive range D. When the drive range D is selected (Yes), this control proceeds to step S130 to determine whether or not there is an obstacle in front of the drive range D.

On the other hand, if the drive range D is not selected in step S120 (No), this control proceeds to step S140 to determine whether or not the speed change operating device 20 is selected from the parking range P to the reverse range R. .. When the reverse range R is selected (Yes), this control proceeds to step S150 and determines whether or not there is an obstacle behind.

If the determination in step S120 and the determination in step S140 are both negative (No), the speed change operation device 20 is not selected for either the drive range D or the reverse range R, and is maintained in the parking range P. It will be. In this case, this control is returned.

If it is determined in step S130 that there is an obstacle in front (Yes), the process proceeds to step S132, and the start prevention control for holding the _{brake pressure P at the holding brake pressure P_S is executed.} In step S134, it is determined whether or not there is no obstacle in front. When there is an obstacle in front (No), this control is returned to the process of step S132 in order to continue the start prevention control. On the other hand, when there is no obstacle in front (Yes), this control proceeds to step S136, releases the start prevention control, and then returns.

If it is determined in step S150 that there is an obstacle behind (Yes), the process proceeds to step S152, and start prevention control for holding the _{brake pressure P at the holding brake pressure P_S is executed.} In step S154, it is determined whether or not there is no obstacle behind. When there is an obstacle behind (No), this control is returned to the process of step S152 in order to continue the start prevention control. On the other hand, when there are no obstacles behind (Yes), the present control proceeds to step S156, the start prevention control is released, and then the control is returned.

FIG. 5 is a flow chart of start prevention control when the vehicle 1 is stopped while traveling.

In step S200, it is determined whether or not the brake pedal 40 is depressed. When the brake pedal 40 is depressed (Yes), this control proceeds to step S210.

In step S210, it is determined whether or not the vehicle 1 has stopped. When the vehicle 1 is stopped (Yes), this control proceeds to step S220, _{and stores the holding brake pressure P_S} in the brake pressure storage unit 120. Next, in step S230, it is determined whether or not the currently selected range is the drive range D. In the case of the drive range D (Yes), this control proceeds to step S240 and determines whether or not there is an obstacle in front of the drive range D.

On the other hand, if the drive range D is not selected in step S230 (No), the control proceeds to step S250 to determine whether or not the currently selected range is the reverse range R. In the case of the reverse range R (Yes), this control proceeds to step S260 to determine whether or not there is an obstacle behind.

If the determination in step S230 and the determination in step S250 are both negative (No), it is presumed that the speed change operating device 20 is operated in the parking range P at the same time as the vehicle 1 is stopped. In this case, this control is returned without executing the start prevention control.

If it is determined in step S240 that there is an obstacle in front (Yes), the process proceeds to step S242, and the start prevention control for holding the _{brake pressure P at the holding brake pressure P_S is executed.} Next, in step S244, it is determined whether there is no obstacle in front of the vehicle, or whether the release condition for operating the speed change operation device 20 in the parking range P is satisfied. If neither of the release conditions is satisfied (No), this control is returned to the process of step S242 in order to continue the start prevention control. On the other hand, if any of the release conditions is satisfied (Yes), this control proceeds to step S246, releases the start prevention control, and then returns.

If it is determined in step S260 that there is an obstacle behind (Yes), the process proceeds to step S262, and the start prevention control for holding the _{brake pressure P at the holding brake pressure P_S is executed.} Next, in step S264, it is determined whether there is no obstacle behind, or whether any of the release conditions in which the speed change operation device 20 is operated by the parking range P is satisfied. If neither of the release conditions is satisfied (No), this control is returned to the process of step S262 in order to continue the start prevention control. On the other hand, if any of the release conditions is satisfied (Yes), the control proceeds to step S266, the start prevention control is released, and then the control is returned.

According to the present embodiment described in detail above, when the vehicle 1 is stopped and there is an obstacle in front of or behind the vehicle 1 that may collide or come into contact, the brake pressure P of the brake device 30 _Is configured to execute start prevention control that holds the vehicle at the holding brake pressure P_S when the vehicle is stopped. This makes it possible to effectively prevent the vehicle 1 from accidentally starting due to the driver's careless accelerator operation or creep torque in the presence of obstacles, and there is a risk of collision or contact between the vehicle 1 and the obstacle. It becomes possible to surely reduce the property.

[others]
The present disclosure is not limited to the above-described embodiment, and can be appropriately modified and implemented without departing from the spirit of the present disclosure.

For example, in the above embodiment, the start prevention control has been described as being released when there are no obstacles in front or behind, but after the obstacles in front or behind have disappeared, the driver depresses the accelerator pedal 41. Along with this, the accelerator opening sensor 91 may be configured to release the accelerator opening degree Ac when it is detected by the accelerator opening degree sensor 91. With this configuration, for example, when the vehicle 1 stops on a steep uphill or downhill, it is possible to effectively prevent the vehicle 1 from moving forward or backward against the driver's intention due to its own weight. become.

Further, the start prevention control may be configured so that it can be appropriately released according to the driver's intention by operating the brake pedal 40 or a release button (not shown) provided in the driver's cab or the like. Further, while the start prevention control is in operation, a function may be added to notify the driver by display, voice, or the like that the control is being executed.

Further, the brake device 30 is not limited to the air type air brake device, and can be widely applied to a fluid-operated pressure type brake device such as a hydraulic type.

1 Vehicle 17L, 17R Drive wheels (wheels)
18L, 18R steering wheel (wheel)
30 Brake device 33 Brake valve 40 Brake pedal 91 Accelerator opening sensor (accelerator opening detection means)
92 Vehicle speed sensor (stop detection means)
93 Brake pressure sensor 94 Brake pedal sensor 95 Shift position sensor 96 Front obstacle acquisition unit 97 Rear obstacle acquisition unit 100 Control device 110 Front / rear obstacle determination unit (obstacle determination means)
120 Brake pressure storage unit 130 Start prevention control unit (control means)

Claims (4)

A braking device that is mounted on a vehicle and can be activated by supplying a predetermined fluid pressure to apply a braking force to the wheels of the vehicle.
A vehicle stop detection means for detecting whether the vehicle has stopped, and
An obstacle determining means for determining whether or not there is an obstacle that may collide with or come into contact with the vehicle around the vehicle.
When it is determined that the obstacle is present when the vehicle is detected to be stopped, the fluid pressure of the braking device is maintained at the fluid pressure when the vehicle is stopped to prevent the vehicle from starting. A braking device including a control means for executing start prevention control. The brake device according to claim 1, wherein the control means releases the start prevention control when it is determined by the obstacle determination means that the obstacle has disappeared after the start prevention control is executed. Further equipped with an accelerator opening detection means for detecting the accelerator opening according to the driver's depression of the accelerator pedal.
After executing the start prevention control, the control means determines that the obstacle has disappeared by the obstacle determining means, and further, when the accelerator opening degree detecting means detects the accelerator opening degree, the starting prevention means is prevented. The brake device according to claim 2, wherein the control is released. It is a control method of a braking device which is mounted on a vehicle and can be operated by supplying a predetermined fluid pressure to apply a braking force to the wheels of the vehicle.
When the vehicle is detected to be stopped, it is determined whether or not there is an obstacle around the vehicle that may collide with or come into contact with the vehicle, and when the vehicle is detected to be stopped, the obstacle is detected. A method for controlling a brake device, which comprises performing start prevention control for preventing the vehicle from starting by holding the fluid pressure of the brake device at the fluid pressure when the vehicle is stopped. ..

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