JP2011051477A - Vehicle follow-up control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle follow-up control device for skipping the manual setting of a target speed. <P>SOLUTION: This vehicle follow-up control device is provided with: an accelerator opening sensor 110 for detecting the accelerator operation state of a driver; and a brake ECU102 equipped with a speed control part 102a for, when accelerator OFF is detected by the accelerator opening sensor 110, performing follow-up control to maintain a relative relation between a self-vehicle and a preceding vehicle. The brake ECU102 is provided with an upper limit vehicle speed setting part 102b for, on the basis of the speed of a self-vehicle when the follow-up control is performed by the speed control part 102a, setting the upper limit vehicle speed in the case of follow-up control. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vehicle following control device.

  In the vehicle follow-up control device of Patent Document 1, when the driver's accelerator operation is detected during the inter-vehicle distance control for maintaining the inter-vehicle distance between the host vehicle and the preceding vehicle constant, the inter-vehicle distance control is temporarily interrupted, and then the accelerator operation is performed. The vehicle distance control is restored at the time when the operation is completed.

JP 2004-216965 A

However, in the above prior art, when the inter-vehicle distance control is performed, the driver needs to manually set the target vehicle speed by operating a switch, and there is a problem that the setting operation is troublesome.
An object of the present invention is to provide a vehicle follow-up control device that can omit manual setting of a target vehicle speed.

  In the present invention, when a change in the accelerator operation state in the decreasing direction is detected, the tracking control means for intervening in the tracking control for maintaining the relative relationship between the host vehicle and the preceding vehicle, and the speed of the host vehicle at the time of the tracking control intervention And a vehicle speed setting means for setting a vehicle speed limit for the follow-up control.

  According to the present invention, manual setting of the target vehicle speed can be omitted.

It is a block diagram of the speed control apparatus of Example 1. 3 is a flowchart showing a flow of speed control processing by a speed control unit 102a of a brake ECU 102. 7 is a flowchart showing a flow of an upper limit vehicle speed setting process in step S3. It is a time chart which shows a motion of each signal of speed control when a driver turns from accelerator ON to OFF during driving. It is a time chart which shows movement of each signal of speed control when a driver turns off from accelerator ON at the time of start.

  EMBODIMENT OF THE INVENTION Hereinafter, the form for implement | achieving the vehicle following control apparatus of this invention is demonstrated by the Example based on drawing.

First, the configuration will be described.
FIG. 1 is a configuration diagram of a speed control apparatus according to the first embodiment.
The brake hydraulic pressure unit 101 controls the brake hydraulic pressure of the wheel cylinders 114a, 114b, 114c, 114d provided on the wheels 113a, 113b, 113c, 113d in accordance with a command from the brake ECU (control unit) 102.
The brake ECU 102 applies braking force to the wheels 113a, 113b, 113c, and 113d based on information from the master cylinder pressure sensor 104 and the wheel speed sensors 105a, 105b, 105c, and 105d. The brake ECU 102 includes a speed control unit (following control unit) 102a and an upper limit vehicle speed setting unit (restricted vehicle speed setting unit) 102b, a master cylinder pressure sensor 104, wheel speed sensors 105a, 105b, 105c, and 105d, and speed control permission. Based on information from the SW 106, the camera 107, the engine ECU 108, and the longitudinal acceleration sensor 111, speed control is executed. Details of the speed control will be described later.
The brake pedal 103 is operated when the driver performs braking, and generates a braking force.
The master cylinder pressure sensor 104 detects the pressure (master cylinder pressure) generated in the master cylinder.
The right front wheel speed sensor 105a detects the wheel speed of the right front wheel 113a. The left front wheel speed sensor 105b detects the wheel speed of the left front wheel 113b. The right rear wheel speed sensor 105c detects the wheel speed of the right rear wheel 113c. The left rear wheel speed sensor 105d detects the wheel speed of the left rear wheel 113d.

The speed control permission SW 106 switches speed control ON / OFF by the driver's operation.
The camera 107 detects the distance to the target existing in front of the host vehicle and the speed of the target, and transmits a detection signal to the brake ECU 102 by CAN communication. In the first embodiment, the object is a preceding vehicle (including a preceding vehicle that is stopped).
The engine ECU 108 detects the driver's accelerator operation amount from an accelerator opening sensor (accelerator operation state detection means) 110, and controls the engine 112 as a drive source so as to generate engine torque according to the accelerator operation amount. When a target engine torque request is transmitted from the brake ECU 102 via CAN communication, the engine ECU 108 generates engine torque according to the target longitudinal acceleration.
The accelerator pedal 109 is operated when the driver accelerates.
The accelerator opening sensor 110 detects a driver's accelerator pedal operation amount.
The longitudinal acceleration sensor 111 detects vehicle longitudinal acceleration.

Details of the speed control will be described below.
[Speed control processing]
FIG. 2 is a flowchart showing the flow of speed control processing by the speed control unit 102a of the brake ECU 102. Each step will be described below. This process is repeatedly executed at a predetermined calculation cycle.
In step S1, it is determined whether or not the speed control permission SW 106 is ON. If YES, the process proceeds to step S2, and if NO, the process proceeds to step S9.
In step S2, it is determined whether or not both the accelerator and the brake are OFF. If YES, the process proceeds to step S3. If NO, the process proceeds to step S9. When the accelerator operation amount detected by the accelerator opening sensor 110 is zero, it is determined that the accelerator is OFF. When the master cylinder pressure from the master cylinder pressure sensor 104 is a numerical value indicating atmospheric pressure, it is determined that the brake is OFF.
In step S3, the upper limit vehicle speed setting unit 102b performs upper limit vehicle speed setting processing for setting the upper limit vehicle speed for speed control (restricted vehicle speed), and the process proceeds to step S4. The upper limit vehicle speed setting process will be described later.
In step S4, it is determined from the detection signal of the camera 107 whether or not the object is detected within the tracking control permission range. If YES, the process proceeds to step S5. If NO, the process proceeds to step S6. Here, the follow-up control permission range refers to a range between the minimum control range (predetermined inter-vehicle time minimum value × vehicle speed) and the maximum control range (predetermined inter-vehicle time maximum value × vehicle speed).
In step S5, it is determined whether or not the speed of the object is lower than the upper limit vehicle speed set in the upper limit vehicle speed setting process in step S3. If YES, the process proceeds to step S7. If NO, the process proceeds to step S6.
In step S6, it is determined whether or not the own vehicle speed is higher than a predetermined vehicle speed (for example, 40 km / h). If YES, the process proceeds to step S8, and if NO, the process proceeds to step S9. An arbitrary speed can be set as the predetermined vehicle speed.
In step S7, follow-up control is executed, and the process proceeds to return. In the follow-up control, a target vehicle speed is set such that the relative speed between the host vehicle and the object is zero, and the brake hydraulic unit 101 and the engine 112 are driven so that the host vehicle speed becomes the target vehicle speed.
In step S8, constant speed traveling control is performed, and the process proceeds to return. In the constant speed traveling control, the upper limit vehicle speed set in step S3 is set as the target vehicle speed, and the brake fluid pressure unit 101 and the engine 112 are controlled so that the host vehicle speed becomes the target vehicle speed. The target vehicle speed may be the vehicle speed when the driver turns the accelerator from ON to OFF.
In step S9, non-control in which neither the follow-up control nor the constant speed traveling control is executed is performed, and the process proceeds to return.

[Upper limit vehicle speed setting process]
FIG. 3 is a flowchart showing the flow of the upper limit vehicle speed setting process in step S3, and each step will be described below.
In step S31, it is determined whether or not the accelerator is OFF. If YES, the process proceeds to step S32. If NO, the process proceeds to step S34.
In step S32, it is determined whether or not the previous accelerator value is ON. If YES, the process proceeds to step S33, and if NO, this control is terminated. Here, when the accelerator operation amount one control cycle before the speed control process shown in FIG. 2 is larger than zero, it is determined that the previous accelerator value is ON.
In step S33 (speed comparison means), a value obtained by adding a predetermined value (for example, 30 km / h) to the current vehicle speed is compared with a preset reference upper limit vehicle speed (first vehicle speed), and the larger value is obtained. Is set to the upper limit vehicle speed, and this control is terminated. Here, the reference upper limit vehicle speed is set to the upper limit of the vehicle speed range that is normally used in urban driving, for example, 60 km / h.
In step S34, the reference upper limit vehicle speed is set to the upper limit vehicle speed, and this control is terminated.
Here, in addition to step S31 and step S32, it is also conceivable to set the upper limit vehicle speed based on the determination from ON to OFF of the brake pedal 103. Therefore, in the first embodiment, the upper limit vehicle speed is not set so that the vehicle accelerates based on the brake pedal operation.

Next, the operation will be described.
[Following vehicle by speed feedback]
In the first embodiment, when the driver is turning on the speed control permission SW 106 and the accelerator and the brake are both turned from ON to OFF, the preceding vehicle (object) is within the following control permission range. Then, follow-up control for causing the own vehicle speed to follow the speed of the preceding vehicle is performed (step S1, step S2, step S3, step S4, step S5, step S7). In the follow-up control, a target vehicle speed is set such that the relative speed between the host vehicle and the preceding vehicle is zero, and speed feedback control is performed to match the host vehicle speed with the target vehicle speed.
In addition, as another follow-up control, distance feedback control may be performed to make the inter-vehicle distance between the preceding vehicle and the host vehicle coincide with the target inter-vehicle distance.For example, when the preceding vehicle stops and the speed becomes zero, In some cases, the vehicle cannot be stopped following the vehicle and cannot continue to follow the preceding vehicle. For this reason, although it can cope with traveling on a highway where the speed of the preceding vehicle does not become zero, speed control cannot be continued when traveling in an urban area where the speed of the preceding vehicle frequently becomes zero.
On the other hand, in the follow-up control according to the first embodiment, the preceding vehicle is followed by the speed feedback control. Therefore, when the preceding vehicle stops, the host vehicle can be stopped. In other words, since speed control can be continued even when the speed of the preceding vehicle becomes zero, it is possible not only when driving on highways but also when driving on urban areas, compared to conventional tracking control that performs distance feedback control The applicable scene can be expanded. Further, in the deceleration control of the first embodiment, since the target inter-vehicle distance is not set and the speed feedback control is performed when the inter-vehicle distance between the host vehicle and the preceding vehicle is within the follow-up control permission range, it is compared with the distance feedback control. Thus, followability and control responsiveness can be improved.
In the first embodiment, accelerator ON → OFF or brake ON → OFF is used as a trigger for the driver to intervene in speed control, and speed control is started when accelerator ON → OFF or brake ON → OFF is detected. For this reason, the driver can change the relative relationship with the preceding vehicle by simply turning one of the brake pedal 103 and the accelerator pedal 109 on and off during the speed control, and intervention in the speed control is easy.

[Speed limit by upper limit vehicle speed]
In the first embodiment, when the vehicle speed of the preceding vehicle reaches the upper limit vehicle speed during the follow-up control, the control shifts from the follow-up control to the constant speed travel control (Step S1, Step S2, Step S3, Step S4, Step S5, Step S6). → Step S8). In the constant speed traveling control, the upper limit vehicle speed is set as the target vehicle speed, and the speed feedback control is performed so that the own vehicle speed matches the target vehicle speed.
As described above, in the follow-up control of the first embodiment, since the speed feedback control is performed to make the own vehicle speed follow the speed of the preceding vehicle, when the preceding vehicle continues to accelerate, the own vehicle accelerates following the acceleration, The vehicle speed may increase to a speed that the driver does not want. As a countermeasure, in the first embodiment, an upper limit is set to the follow-up speed by the upper limit vehicle speed, and the own vehicle speed is prevented from being unnecessarily increased following the acceleration of the preceding vehicle.
At this time, the upper limit vehicle speed is set to a value obtained by adding a predetermined value (30 km / h) to the host vehicle speed at the time of speed control intervention (step S31 → step S32 → step S33). The own vehicle speed at the time of the speed control intervention is a speed determined by the driver's own accelerator operation, and can be said to be a speed desired by the driver. Therefore, by making the upper limit vehicle speed a speed that exceeds this speed by a predetermined value (30 km / h), it is possible to suppress the vehicle speed from deviating from the vehicle speed that the driver is aware of (the vehicle speed at the time of speed control intervention).
In the conventional follow-up control, the driver manually sets the target vehicle speed by operating the switch. However, in the follow-up control in the first embodiment, the upper limit vehicle speed, that is, the target vehicle speed is determined by the own vehicle speed at the time of speed control intervention. Manual setting of the target vehicle speed can be omitted.
In the speed control of the first embodiment, the upper limit vehicle speed is always higher than the own vehicle speed at the time of speed control intervention. For example, when the upper limit vehicle speed is set to a constant vehicle speed, if the host vehicle speed at the time of speed control intervention is higher than the upper limit vehicle speed, the vehicle immediately shifts to the constant speed traveling control and the follow-up control cannot be performed. Therefore, by making the upper limit vehicle speed always higher than the own vehicle speed at the time of speed control intervention, the follow-up control can be performed regardless of the own vehicle speed at the time of speed control intervention, and an appropriate following speed range can be set.
In the speed control of the first embodiment, a value obtained by adding a predetermined value (30 km / h) to the own vehicle speed is compared with a reference upper limit vehicle speed (60 km / h), and the higher value is set as the upper limit vehicle speed. For example, if the upper limit vehicle speed is always the value obtained by adding a predetermined value to the vehicle speed at the time of speed control intervention, the vehicle speed of the preceding vehicle will be 30 km / h in the scene where tracking control starts from the start (0 km / h). When this happens, it shifts to constant speed running control and tracking control cannot be continued. On the other hand, by setting the predetermined value added to the vehicle speed at the time of speed control intervention to a large value (for example, 60 km / h), the above problem is solved. However, if the predetermined value is excessively increased, the vehicle speed is It will increase to an undesired speed. In contrast, in the first embodiment, a reference upper limit vehicle speed (60 km / h) is set in advance, and the upper limit vehicle speed is determined by selecting high with a value set at the time of speed control intervention, so that follow-up control is started in a low vehicle speed range. Even in this case, the follow-up control can be continued in the vehicle speed range (0 km / h to 60 km / h) that is normally used in city driving.

FIG. 4 is a time chart showing the movement of each signal for speed control when the driver turns from accelerator ON to OFF during traveling. At time t1, the driver starts operating the accelerator pedal 109, so the host vehicle starts accelerating. At time t2, the acceleration of the host vehicle is terminated by turning off the accelerator. In the speed control, a value obtained by adding a predetermined value to the own vehicle speed when the accelerator pedal 109 is turned off is set as the upper limit vehicle speed. At time t3, the preceding vehicle (object) is detected in the speed control, and the distance from the preceding vehicle is within the follow-up control permission range, so follow-up control is started. In the section from time t3 to t4, the host vehicle speed is reduced because the host vehicle speed is higher than the speed of the preceding vehicle. At time t4, the speed of the preceding vehicle is equal to the speed of the host vehicle, so the distance between the preceding vehicle and the preceding vehicle is kept constant in the section from time t4 to t5. At time t5, the preceding vehicle starts accelerating, and at time t6, the host vehicle follows and starts accelerating. At time t7, since the host vehicle speed has reached the upper limit vehicle speed, the follow-up control is terminated, and constant speed traveling control is started with the upper limit vehicle speed as the target vehicle speed.
FIG. 5 is a time chart showing the movement of each signal for speed control when the driver turns from accelerator ON to OFF when starting. At time t11, since the driver starts operating the accelerator pedal 109, the host vehicle starts. At time t12, the driver ends the operation of the accelerator pedal 109, and the acceleration of the host vehicle ends. In the speed control, the upper limit vehicle speed calculated from the own vehicle speed when the accelerator pedal 109 is turned off is compared with the reference upper limit vehicle speed. At this time, since the reference upper limit vehicle speed is higher than the calculated upper limit vehicle speed, the reference upper limit vehicle speed is set to the upper limit vehicle speed. Furthermore, since the preceding vehicle is detected and the distance to the preceding vehicle is within the tracking control permission range, the tracking control is started. In the section from time t12 to t13, the host vehicle speed is accelerated because the host vehicle speed is lower than the speed of the preceding vehicle. At time t13, the speed of the preceding vehicle is equal to the speed of the host vehicle, so the distance between the preceding vehicle and the preceding vehicle is kept constant in the section from time t13 to t14. At time t14, the preceding vehicle starts accelerating, and at time t15, the host vehicle follows and starts accelerating. At time t16, since the host vehicle speed has reached the upper limit vehicle speed, the follow-up control is terminated, and constant speed running control is started with the upper limit vehicle speed as the target vehicle speed.

Next, the effect will be described.
The vehicle follow-up control device according to the first embodiment has the following effects.

(1) Accelerator opening sensor 110 that detects the driver's accelerator operation state, and the speed to intervene in follow-up control that maintains the relative relationship between the host vehicle and the preceding vehicle when accelerator OFF is detected by the accelerator opening sensor 110 A brake ECU 102 having a control unit 102a, and the brake ECU 102 includes an upper limit vehicle speed setting unit 102b that sets an upper limit vehicle speed at the time of the follow-up control based on the speed of the host vehicle at the time of the follow-up control intervention by the speed control unit 102a. It was. Thereby, the manual setting of the target vehicle speed can be omitted.
(2) The upper limit vehicle speed set by the upper limit vehicle speed setting unit 102b is a predetermined speed (30km / h) higher than the speed of the host vehicle at the time of speed control intervention, so regardless of the host vehicle speed at the time of speed control intervention. Tracking control can be performed, and an appropriate tracking speed range can be set.
(3) The upper limit vehicle speed setting unit 102b includes speed comparison means (step S33) for comparing the upper limit vehicle speed set based on the host vehicle speed at the time of speed control intervention with a reference upper limit vehicle speed stored in advance, and at the time of speed control intervention. When the upper limit vehicle speed is lower than the reference upper limit vehicle speed, the reference upper limit vehicle speed is set as the upper limit vehicle speed. Thereby, even if it is a case where follow-up control is started in the low vehicle speed range, follow-up control can be continued in the range (0 km / h to 60 km / h) of the vehicle speed range normally used in city driving.

(Other examples)
As mentioned above, although the form for implementing this invention was demonstrated based on the Example, the specific structure of this invention is not limited to the structure shown in the Example, and does not deviate from the summary of invention. Any change in the design of the range is included in the present invention.
In the first embodiment, the example is shown in which the speed control is started when the accelerator OFF is detected. However, the speed control may be started when the change in the accelerator operation amount in the decreasing direction is detected.

102 Brake ECU (control unit)
102a Speed control unit (follow-up control means)
102b Upper limit vehicle speed setting section (restricted vehicle speed setting means)
110 Accelerator opening sensor (accelerator operation state detection means)

Claims (3)

An accelerator operation state detection means for detecting an accelerator operation state of the driver;
A control unit having follow-up control means for intervening in follow-up control for maintaining the relative relationship between the host vehicle and the preceding vehicle when a change in the accelerator operation state in the decreasing direction is detected by the accelerator operation state detection means;
With
The vehicle follow-up control device, wherein the control unit includes a limit vehicle speed setting means for setting a limit vehicle speed during follow-up control based on the speed of the host vehicle during follow-up control intervention by the follow-up control means. The vehicle following control device according to claim 1,
The vehicle following control apparatus characterized in that the vehicle speed limit set by the vehicle limit setting means is a predetermined speed higher than the speed of the host vehicle at the time of the tracking control intervention. In the vehicle follow-up control device according to claim 1 or 2,
The limit vehicle speed setting means includes speed comparison means for comparing a limit vehicle speed set based on the speed of the host vehicle with a first vehicle speed stored in advance, and the set limit vehicle speed is lower than the first vehicle speed. The vehicle follow-up control device characterized in that the first vehicle speed is a limited vehicle speed.

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