FR3066459A1 - DRIVING ASSISTANCE DEVICE - Google Patents

Abstract

A driving assistance device (2) is equipped with a brake force control unit (5) which performs an automatic braking command on the autonomous vehicle (1A) as a function of the relation between operating states of the autonomous vehicle (1A) and a vehicle at the front (1B) and a brake handling detection unit (10) which detects whether brake manipulation has been performed by the driver. When a braking manipulation is detected by the braking handling detection unit (10) during an automatic braking command, the braking force control unit (5) causes a continuation of the braking output (d). a braking force produced by the automatic braking control.

Description

DRIVING ASSISTANCE DEVICE

The present invention relates to a driving assistance device. More particularly, the invention relates to a driving assistance device which performs an automatic braking command to deliver a braking force automatically, that is to say without manipulation of a driver.

Vehicles are known which are equipped with a driving assistance device which automatically controls the driving and braking of the autonomous vehicle so that the autonomous vehicle follows a moving vehicle immediately in front of it (vehicle at the front).

Among the operating control devices for causing the autonomous vehicle to move at a constant speed (automatic cruise control) or to follow a vehicle in front automatically by performing an automatic braking command, one of them is disclosed in JP-A-2008123230. In the vehicle operating control device disclosed in JP-A-2008-123230, a warning is displayed to encourage the driver to perform braking manipulation when deceleration by an automatic braking control is insufficient.

However, in the technique of JP-A-2008-123230, an event may occur in which the driver depresses the brake pedal, as a braking action, during an automatic braking command of a control to cause the autonomous vehicle to automatically follow a vehicle in front. In this case, since a brake pressure is already acting on the brake mechanism of each wheel under the effect of the automatic brake control, if it is attempted to obtain a brake pressure higher than the brake pressure of automatic braking control, a greater handling force must be exerted on the brake pedal than in a case in which no automatic braking control is performed.

More specifically, with reference to Figures 2 and 5, an autonomous vehicle

IA approaches a vehicle in front of IB. When an automatic braking command (ACC command) is triggered at a time t0, a first cut-off valve 14A and a second cut-off valve 14B are closed and a first pressure build-up valve 15A and a second build-up valve pressure 15B are open. The braking pressure is increased by the activation of a pump motor 12, so that the braking force begins to increase. The braking force becomes equal to a set braking force Fa at a time tl, at the expiration of a certain time RI from the time tO, and the set braking force Fa is then maintained.

The autonomous vehicle IA is closer to the front vehicle IB. Since the set braking force Fa of the automatic braking control (ACC command) is insufficient, a warning "Press the brake pedal" is issued at a time t2, at the expiration of a certain time R2 from the time tl. In response, the driver presses the brake pedal as a brake action. Brake manipulation is recognized by a brake manipulation detection unit (brake pedal switch) or based on brake master cylinder pressure sensor information and the automatic brake control (ACC control) is completed, after which the first shutoff valve 14A and the second shutoff valve 14B are opened and the first pressure build-up valve 15A and the second pressure build-up valve 15B are closed. Thus, the pump motor 12 is deactivated. At this point, the brake pressure produced by the automatic brake control acts on the brake mechanism of each wheel.

However, in the above operation, when the driver presses the brake pedal as a braking action, the brake pressure of the automatic brake control (ACC control) already acts on the brake mechanism of each wheel and the first cut-off valve 14A and the second cut-off valve 14B are open and the first pressure build-up valve 15A and the second pressure build-up valve 15B are closed. Thus, the driver cannot feel a brake pedal stroke at an initial stage of braking as he would feel in a case in which no automatic braking command is performed; the driver would feel that the brake pedal is hard.

The brake pedal pressure distance reaches a value S at a time t3, at the expiration of a certain time R3 from the time t2, and the pressure distance S is then maintained.

When a distance sufficient to prevent a collision between the autonomous vehicle IA and the vehicle at the front IB is produced at a time t4, at the expiration of a certain time R4 from the time t3, the braking manipulation is canceled by the driver, after which the braking force begins to decrease from the setpoint Fa and the pressure distance also begins to decrease.

At a time t5, at the expiration of a certain time R5 from time t4, the braking force and the pressure distance become zero.

As described above, when the driver presses the brake pedal as a brake action during an automatic brake control (ACC command), the driver may feel that the brake pedal is hard, which is an inconvenience. It is therefore desirable to resolve this problem.

An object of the invention is to provide a driving assistance device capable of preventing a driver from feeling that a brake pedal is hard and of preventing insufficient braking force.

The invention relates to a driving assistance device which automatically controls the driving and braking of an autonomous vehicle so that the autonomous vehicle follows a vehicle in front, and which comprises a braking force control unit. performing automatic braking control on the autonomous vehicle based on a relationship between operating states of the autonomous vehicle and the vehicle ahead and a brake manipulation detection unit detecting whether a brake manipulation has been performed by a driver, wherein: when braking manipulation is detected by the braking manipulation sensing unit during automatic braking control, the braking force control unit causes a continuation of an output d '' a braking force produced by the automatic braking control.

When braking is performed by the driver during an automatic braking command causing an automatic output of a braking force without manipulation by the driver, the output of a braking force by the automatic braking control is continued so as to produce a braking force greater than a braking force corresponding to the braking manipulation. This is to prevent the driver from feeling a hard brake pedal and to prevent insufficient braking force.

FIG. 1 represents the system configuration of a vehicle which is equipped with a driving assistance device according to an embodiment of the present invention.

FIG. 2 is a diagram of the oil pressure circuit of the vehicle which is equipped with the driving assistance device according to the embodiment.

FIG. 3 is a flow diagram of a driving assistance command according to the embodiment.

FIG. 4 is a timing diagram of the driving assistance command according to the embodiment.

Figure 5 is a timing diagram of a conventional driving assistance control.

In the accompanying drawings, the reference numbers have the following meanings:

1A: autonomous vehicle

IB: vehicle in front: driving assistance device: automatic vehicle distance control unit (ACCECU): automatic constant speed control unit (ECM): braking force control unit (ESP): warning output unit (IPC): front vehicle detection unit: cruise control switch: brake pedal: brake manipulation detection unit (brake pedal switch): vehicle detection unit acceleration (gravity / yaw sensor): pump sensor: warning unit

14A: first cut-off valve

14B: second shut-off valve

15A: first pressure accumulation valve

15B: second pressure accumulation valve

The present invention achieves the objective of preventing a driver from feeling that a brake pedal is hard and of preventing an insufficient braking force by maintaining an output of a braking force by a control. automatic braking even after the driver has performed a braking action during the automatic braking command.

Figures 1 to 4 illustrate an embodiment of the invention. As shown in FIGS. 1 and 4, an autonomous vehicle IA is equipped with a driving assistance device (ACC system) 2. The driving assistance device 2 automatically controls the driving and braking of the autonomous vehicle IA so that the autonomous vehicle IA follows a vehicle IB moving immediately in front of it (vehicle at the front).

As shown in FIG. 1, the driving assistance device 2 is equipped with an automatic vehicle distance control unit (ACCECU) 3, with an automatic constant speed control unit (ECM) 4 , a brake force control unit (ESP) 5, and a warning output unit (IPC) 6.

A front vehicle detection unit (radar) 7 for detecting information relating to the front vehicle IB is connected to the automatic vehicle distance control unit 3. A cruise control switch 8 which is activated / deactivated by a manipulation of the driver is connected to the automatic constant speed control unit 4. A braking manipulation detection unit (brake pedal switch) 10 for detecting a braking manipulation, i.e. say a pressure manipulation on a brake pedal 9, of the driver, an acceleration detection unit (gravity / yaw sensor) 11 for detecting an acceleration state of the autonomous vehicle 1 A, and a pump motor 12 to apply brake pressure on the brake mechanism of each wheel are connected to the brake force control unit 5. A warning unit 13 to warn the driver is connected e to the output unit 6 warning.

The automatic vehicle distance control unit 3, which is a computer, acquires front vehicle information IB from the front vehicle detection unit 7.

The automatic constant speed control unit 4, which is a computer, controls the torque of the autonomous vehicle IA according to the activation / deactivation of the cruise control switch 8 (acceleration / deceleration control).

The braking force control unit 5, which is a computer, performs an automatic braking command (ACC command) on the autonomous vehicle 1A as a function of the relationship between operating states of the autonomous vehicle IA and of the vehicle at l 'before IB, performs a braking command (deceleration command) on the autonomous vehicle IA according to a detection state of the braking manipulation detection unit 10, and operates the pump motor 12. L' braking force control unit 5 can acquire information such as a vehicle speed of the autonomous vehicle IA as well as a distance between vehicles and a relative speed between the autonomous vehicle 1A and the vehicle at the front IB.

The warning output unit 6, which is a computer, issues a warning signal to the warning unit 13.

The automatic vehicle distance control unit 3 is connected to the automatic constant speed control unit 4, the braking force control unit 5, and the warning output unit 6 and it can communicate with each other.

As with the operation between the automatic vehicle distance control unit 3 and the automatic constant speed control unit 4, the automatic vehicle distance control unit 3 sends a torque request signal (request for acceleration / deceleration request) to the automatic constant speed control unit 4 and the automatic constant speed control unit sends an on / off status signal from the cruise control switch 8 and a signal from torque information at the automatic distance control unit between vehicles 3.

As with the operation between the automatic vehicle distance control unit 3 and the braking force control unit 5, the automatic vehicle distance control unit 3 sends a braking request signal (deceleration request ) to the brake force control unit 5 and the brake force control unit 5 sends a wheel speed signal, a yaw rate signal, and an ABS / ESP operation flag signal to the 'automatic distance control unit between vehicles 3.

As with the operation between the automatic vehicle distance control unit 3 and the warning output unit 6, the automatic vehicle distance control unit 3 sends a unit activation request signal d warning, ACC mode signal, vehicle distance signal, and set vehicle speed signal to warning output unit 6 and warning output unit 6 sends a signal IPC vehicle speed display at the automatic vehicle distance control unit 3.

In the embodiment, when a braking manipulation is detected by the braking manipulation detection unit 10 during an automatic braking command, the braking force control unit 5 causes the continuation of the output of a braking force Fa produced by the automatic braking control.

When a brake manipulation is detected by the brake manipulation detection unit 10 during an automatic braking command, the braking force control unit 5 causes an output of a braking force which is greater than a braking force corresponding to the braking manipulation.

In addition, when a brake manipulation is detected by the brake manipulation detection unit 10 during an automatic brake control, the brake force control unit 5 causes the output of the brake to continue. a braking force Fa produced by the automatic braking control provided that the braking force Fa is less than a braking force Fb which is necessary to prevent a collision between the autonomous vehicle 1A and the front vehicle IB.

In addition, when a braking manipulation is detected by the braking manipulation detecting unit 10 during an automatic braking command, the braking force control unit 5 causes an output of a braking force. braking which is greater than a braking force corresponding to the braking manipulation provided that a braking force Fa produced by the automatic braking control is less than a braking force Fb which is necessary to prevent a collision between the autonomous vehicle 1A and the vehicle at the front IB.

The warning output unit 6 sends a warning signal to the warning unit 13 if a braking force Fa produced by an automatic braking command is less than a braking force Fb which is necessary to prevent a collision between the autonomous vehicle 1A and the vehicle at the front IB.

In the embodiment, if a deceleration of an automatic braking command which is carried out on the autonomous vehicle IA is insufficient, the driver is encouraged to perform braking manipulation and, even if the driver performs braking manipulation, a output of a braking force Fa by the automatic braking control is continued, so that a braking force greater than a braking force corresponding to the braking manipulation of the driver is produced.

A driving assistance command according to the embodiment will be described below with reference to a flow diagram of FIG. 3.

As shown in FIG. 3, in the braking force control unit 5, as soon as a program is started in step A01, a vehicle speed of the autonomous vehicle IA as well as a distance between vehicles and a relative speed between the autonomous vehicle IA and the vehicle at the front IB is acquired in step A02.

In step A03, it is judged whether or not the autonomous vehicle IA requires braking.

If the autonomous vehicle IA requires braking (A03: yes), in step A04 a first shut-off valve 14A and a second shut-off valve 14B are closed, a first pressure accumulation valve 15A and a second shut-off valve. pressure build-up 15B is opened, and an automatic brake control (ACC command) is triggered.

In step A05, it is judged whether the braking force Fa of the automatic braking control is less than or not less than a braking force Fb which is necessary to prevent a collision between the autonomous vehicle 1A and the vehicle at the front IB (i.e. Fa <Fb). If Fa <Fb (A05: yes), in step A06 the warning output unit 6 sends a warning signal to the warning unit

13.

In step A07, it is judged whether the braking manipulation detection unit 10 has detected or not a braking manipulation of the driver. If it is judged that a braking manipulation has been detected (A07: yes), in step A08 the automatic braking command is continued with the first cut-off valve 14A and the second cut-off valve 14B kept closed and the first pressure accumulation valve 15A and the second pressure accumulation valve 15B kept open.

In step A09, a braking force which is the braking force Fa produced by the automatic braking command plus a braking force corresponding to the braking manipulation, that is to say a braking force greater than the braking force corresponding to the braking manipulation, is delivered.

When step A09 has been executed, it is judged that braking is not necessary (A03: no), a judgment Fa> Fb is made (A05: no), or no braking manipulation is detected ( A07: no), the execution of the program is ended in step A10.

The driving assistance command according to the embodiment will be described below with reference to a timing diagram in FIG. 4.

As shown in Figure 4, the autonomous vehicle IA approaches the vehicle at the front IB. When an automatic braking command (ACC command) is triggered at a time t0, the first cut-off valve 14A and the second cut-off valve 14B are closed and the first pressure build-up valve 15A and the second build-up valve pressure 15B are open. The brake pressure is increased by the activation of the pump motor 12 by the brake force control unit 5, so that the braking force begins to increase. The braking force becomes equal to a setpoint value Fa at a time tl, at the expiration of a certain time RI from the time tO, and the set braking force Fa is then maintained.

The autonomous vehicle IA is closer to the front vehicle IB.

Since the set braking force Fa of the automatic braking control (ACC command) is insufficient, a warning "Press the brake pedal" is issued at a time t2, at the expiration of a certain time R2 from the ίο time tl. In response, the driver depresses the brake pedal 9, as a brake manipulation.

However, in the embodiment, even if the driver depresses the brake pedal 9 as braking manipulation and the braking manipulation is recognized by the braking manipulation detection unit (brake pedal switch) 10 or based on brake master pressure sensor information, the automatic brake control (ACC command) is continued. The first shutoff valve 14A and the second shutoff valve 14B are kept closed and the first pressure build-up valve 15A and the second pressure build-up valve 15B are kept open. The brake force control unit 5 causes the pump motor 12 to continue to operate. Consequently, the driver performs the braking manipulation without feeling that the brake pedal is hard and therefore without feeling unpleasant. The brake pressure begins to increase again. Thus, the braking force control unit 5 produces a braking force which is greater than a braking force corresponding to the braking manipulation (brake assist).

At a time t3, at the expiration of a certain time R3 from the time t2, a braking force Fb which is necessary to prevent a collision between the autonomous vehicle IA and the vehicle at the front IB is obtained and then maintained . The pressure distance of the brake pedal 9 is maintained at a value SI which is greater than the conventional value S.

As soon as a distance sufficient to prevent a collision between the autonomous vehicle IA and the vehicle at the front IB is produced at a time t4, at the expiration of a certain time R4 from the time t3, the control unit braking force 5 begins to reduce the operating level of the pump motor 12 and the driver begins to decrease the pressure distance of the brake pedal 9.

At a time t5, at the expiration of a certain time R5 from the time t4, the braking force control unit 5 stops the operation of the pump motor and the driver completes the pressure manipulation on the brake pedal 9, that is to say that the pressure distance becomes zero.

With the above-mentioned operation, in the embodiment, when a braking manipulation is detected by the braking manipulation detecting unit 10 during an automatic braking command, the braking force control unit 5 causes the continuation of the output of a braking force Fa produced by the automatic braking control. Consequently, even if a braking manipulation is carried out during the automatic braking control, since the braking force Fa continues to be delivered, the driver does not feel that the brake pedal 9 is hard or insufficient force braking does not occur.

When a brake manipulation is detected by the brake manipulation detection unit 10 during an automatic braking command, the braking force control unit 5 causes the output of a braking force which is greater than a braking force corresponding to the braking manipulation. Since the braking force which is greater than the braking force corresponding to the braking manipulation is delivered when the braking manipulation is performed during the automatic braking control, the driver experiences less insufficient pedal travel. brake, that is to say, the driver does not feel that the brake pedal 9 is hard and insufficient braking force does not occur.

When a braking manipulation is detected by the braking manipulation detection unit 10 during an automatic braking command, the braking force control unit 5 causes a continuation of the output of a braking force. Braking Fa produced by the automatic braking control provided that the braking force Fa is less than a braking force Fb which is necessary to prevent a collision between the autonomous vehicle 1A and the vehicle at the front IB. Consequently, if the braking force Fa produced by the automatic braking control is less than the braking force Fb which is necessary to prevent a collision between the autonomous vehicle IA and the vehicle at the front IB, the force output braking Fa is continued even if the braking manipulation is performed. This is to prevent the driver from feeling that the brake pedal 9 is hard and to prevent insufficient braking force while producing an appropriate braking force.

When a brake manipulation is detected by the brake manipulation detection unit 10 during an automatic braking command, the braking force control unit 5 causes an output of a braking force which is greater than a braking force corresponding to the braking manipulation provided that a braking force Fa produced by the automatic braking control is less than a braking force Fb which is necessary to prevent a collision between the autonomous vehicle 1A and the vehicle at the front IB. Consequently, if the braking force Fa produced by the automatic braking control is less than the braking force Fb which is necessary to prevent a collision between the autonomous vehicle IA and the front vehicle IB, the braking force which is greater than the braking force corresponding to the braking manipulation is produced. This is to prevent the driver from feeling that the brake pedal 9 is hard and to prevent insufficient braking force while producing an appropriate braking force.

The warning output unit 6 causes a warning to be output if a braking force Fa produced by an automatic braking command is less than a braking force Fb which is necessary to prevent a collision between the autonomous vehicle IA and the vehicle at the front IB. This means that the driver is warned if the braking force is insufficient and the automatic braking control is continued even if the driver then performs a braking operation. This makes it possible to prevent the driver from feeling that the brake pedal 9 is hard and to prevent insufficient braking force while encouraging the driver to perform appropriate braking manipulation.

The driving assistance device according to the invention can be applied to various types of vehicles.

Of course, the invention is not limited to the examples of embodiment described and shown above, from which other modes and other embodiments can be provided, without going beyond the ambit of the invention.

Claims (5)

1. Driving assistance device (2) which automatically controls the driving and braking of an autonomous vehicle (IA) so that the autonomous vehicle (IA) follows a vehicle in front (IB), and which comprises a braking force control unit (5) performing automatic braking control (ACC) on the autonomous vehicle (IA) according to a relationship between operating states of the autonomous vehicle (1 A) and the vehicle to the front (IB) and a brake manipulation detection unit (10) detecting whether a braking manipulation has been carried out by a driver, characterized in that: when a braking manipulation is detected by the detection unit brake handling (10) during the automatic braking control (ACC), the braking force control unit (5) causes a continuation of an output of a braking force (Fa) produced by the automatic brake control (ACC) . 2. A driving assistance device (2) according to claim 1, characterized in that, when a braking manipulation is detected by the braking manipulation detection unit (10) during the braking command. automatic (ACC), the braking force control unit (5) causes an output of a braking force (Fa) which is greater than a braking force (Fb) corresponding to the braking manipulation. 3. Driving assistance device (2) according to claim 1 or 2, characterized in that, when a braking manipulation is detected by the braking manipulation detection unit (10) during the command braking force (ACC), the braking force control unit (5) causes the continuation of an output of a braking force (Fa) produced by the automatic braking control (ACC) provided that the force braking force (Fa) produced by the automatic braking control (ACC) is less than a braking force (Fb) which is necessary to prevent a collision between the autonomous vehicle (1 A) and the vehicle at the front (IB) . 4. Driving assistance device (2) according to claim 2, characterized in that, when a braking manipulation is detected by the braking manipulation detection unit (10) during the braking command automatic (ACC), the brake force control unit (5) causes an output of a 5 braking force (Fa) which is greater than a braking force (Fa) corresponding to the braking manipulation provided that the braking force (Fa) produced by the automatic braking control (ACC) is less than a force of braking (Fb) which is necessary to prevent a collision between the autonomous vehicle (IA) and the vehicle at the front (IB). 5. Driving assistance device (2) according to any one of the claims 1 to 4, characterized in that it further comprises a warning output unit (6) which issues a warning if the braking force (Fa) produced by the automatic braking control (ACC) is less than a force brake (Fb) which is necessary to prevent a collision between the autonomous vehicle (IA) and the vehicle ahead (IB).