JPH08119004A - Vehicle speed control device - Google Patents

Abstract

PURPOSE: To make it possible to avoid a danger of colliding with an ahead-going vehicle from behind, by not removing a control operation until the operation is removed by an operation-removal detection means, removal actuations of which do not include a brake actuation, even if a brake-pedal depression is detected, while a decelerating control is being carried out by a vehicle-speed control means. CONSTITUTION: A controller 5 calculates a target of inter-vehicle distance corresponding to a vehicle speed, finds an amount of change in the vehicle speed based on a difference between the calculated target of inter-vehicle distance and an actual inter-vehicle distance, and controls a vehicle-speed control means by means of the amount of change in the vehicle speed from when a control operation is detected starting by an operation-start detection means 3 till the operation is removed by an operation-removal detection means 4. While a decelerating control is being carried out by the vehicle-speed control means, even if a brake-pedal depression is detected by a brake-pedal depression detection means 5, the decelerating control is not removed until the operation is removed by the operation-removal detection means 4. A danger of colliding with an ahead-going vehicle from behind can be hereby avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle speed control device, and more particularly to a vehicle speed control device having an inter-vehicle distance control (following traveling control) function.

[0002]

2. Description of the Related Art In order to improve easy driveability,
Recently, the number of vehicles equipped with a speed control device that performs a constant-speed traveling (auto cruise) function that controls the vehicle to travel at a constant speed has been increasing recently. In this speed control device, the driver operates the accelerator pedal. Without doing so, the engine output is controlled by adjusting the throttle opening etc. so that the speed of the host vehicle can be kept constant.

However, with this speed control device, there is a risk of a rear-end collision when the vehicle ahead is slower than the host vehicle. Therefore, recently, a device has been developed which detects the inter-vehicle distance to a vehicle ahead and maintains a predetermined safe inter-vehicle distance.

The prior art disclosed in Japanese Patent Laid-Open No. 55-86000 and Japanese Patent Laid-Open No. 2-34439, which are examples thereof, calculates a safe inter-vehicle distance according to the vehicle speed, and the forward vehicle is placed within this safe inter-vehicle distance. If there is no vehicle, constant speed running control is performed by targeting the set vehicle speed by adjusting the throttle opening, and if there is a vehicle in front within the safe inter-vehicle distance, the throttle opening is decreased to ensure safety. Follow-up control is performed so that the distance between vehicles is kept.

Further, Japanese Patent Laid-Open No. 55-213312 and Japanese Patent Laid-Open No.
In the conventional technology described in Japanese Patent No. 297339, a driver sets a target inter-vehicle distance, performs speed control so as to be the inter-vehicle distance, and sets the target inter-vehicle distance by the vehicle speed of the host vehicle or the relative speed with the preceding vehicle. I am suggesting something to correct.

Further, in Japanese Patent Laid-Open No. 1-160737, the speed reduction means such as a service brake and an auxiliary brake (exhaust brake, retarder, etc.) is operated to prevent a rear-end collision, depending on the distance between the front vehicle and the relative speed. There are also some.

[0007]

In such a conventional technique, the speed control is automatically released at the same time when the driver depresses the brake pedal.

[0008] This is a situation in which the driver intends to decelerate when the brake pedal is stepped on, for example, when exiting the highway or entering a parking area, or there is a possibility that the driver may collide with a vehicle ahead without decelerating. Because it is considered.

However, if the braking force has already been automatically applied during the speed control, the braking force is also released when the speed control is released, so it is rather difficult to decelerate, and a rear-end collision with a vehicle ahead occurs. There was a risk of triggering.

Therefore, according to the present invention, in order to improve the above-mentioned problems, a means for detecting an actual inter-vehicle distance from a vehicle ahead, a vehicle speed detecting means, a vehicle speed control means, an operation start detecting means, and an operation release detecting means. Then, until the operation start is detected by the operation start detection means and the operation release is performed by the operation release detection means, a target inter-vehicle distance corresponding to the vehicle speed is calculated, and the calculated target inter-vehicle distance and the actual vehicle In a speed control device for a vehicle, which is provided with a controller that obtains a vehicle speed change amount based on a difference with an inter-vehicle distance and controls the vehicle speed control means based on the vehicle speed change amount, and enables constant speed traveling control and inter-vehicle distance control, The purpose is to avoid the risk of a rear-end collision with a vehicle ahead even if the brake pedal is depressed.

[0011]

In order to achieve the above object, a vehicle speed control device according to the present invention is provided with a detection means for detecting the depression of a brake pedal, and the controller detects the depression of the brake pedal. Even when the deceleration control is performed by the vehicle speed control means, the operation is not released until the operation release is performed by the operation release detection means which does not include the brake operation.

Further, the above controller can release the operation even when the operation release detecting means does not release the operation, when the brake pedal stepping detecting means detects the release of the brake pedal.

The target inter-vehicle distance may be set by the target inter-vehicle distance setting means instead of being calculated from the vehicle speed by the controller.

[0014]

In the vehicle speed control device according to the present invention,
The controller first inputs the vehicle speed from the vehicle speed detecting means and then inputs the actual vehicle-to-vehicle distance from the actual vehicle-to-vehicle distance detecting means until the operation start detecting means detects the operation start and the operation release detecting means releases the operation. To do.

Then, the target inter-vehicle distance is calculated based on the current vehicle speed, or the target inter-vehicle distance set by the target inter-vehicle distance setting means is input.

A vehicle speed change amount is obtained based on a difference (target vehicle distance-actual vehicle distance) between the target vehicle distance and the actual vehicle distance detected by the means for detecting the actual vehicle distance from the preceding vehicle, and the vehicle speed change is obtained. The vehicle speed control means is controlled by the minute.

Therefore, when the preceding vehicle is near, the vehicle is decelerated to reach the target inter-vehicle distance, and when the vehicle is far away, the vehicle is accelerated / decelerated so that the vehicle can travel at a constant speed while the target inter-vehicle distance is not reached.

In particular, in the present invention, the controller determines whether or not the vehicle is currently being decelerated by the vehicle speed control means without immediately releasing the speed control even when the driver depresses the brake pedal, When it is found that the deceleration control is not in progress (during constant speed driving), the speed control is deactivated in the same manner as before, but when it is found that the deceleration control is performed, the speed control is not deactivated and the driver However, when the brake operation is released by the operation release detecting means not included in the release operation, or when the brake pedal is released, the operation is released only.

Thus, even if the brake operation is performed, the deceleration can be prevented from being released when there is a risk of a rear-end collision with the vehicle ahead.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing an embodiment of a vehicle speed control device according to the present invention. Each block will be described in sequence.

1: Inter-vehicle distance detecting means Detects an inter-vehicle distance D with a vehicle in front, for example, FM-CW
It is composed of a radar, a laser radar, an ultrasonic sensor, and the like.

2: Vehicle speed detecting means This is composed of a sensor for detecting the traveling speed V of the host vehicle, and usually a reed switch or the like is used.

3: Operation start detection means Usually, it is composed of a digital switch (push switch etc.)
The speed control of the present invention is started when it is detected that the F state is changed to the ON state.

4: Operation release detection means This is for detecting the case where a driver operates a predetermined switch such as a shift lever or a cancel switch to release the speed control of the present invention. Here, the presence or absence of brake operation is included. Not in.

5: Brake pedal depression detecting means, which is constituted by a brake pedal switch or the like, and is turned on / off.
F detects the depression of the brake pedal.

6: Controller An input port 61 for reading the input signals from the above-mentioned means 1-5, a ROM 62 in which the programs shown in FIGS. The control unit includes a RAM 63 that temporarily stores the data, a CPU 64 that performs arithmetic processing based on the program, and an output port 66 that outputs an output signal to each control unit described later.

7: Engine Output Operating Means Normally, it is composed of a motor, a valve, etc., and operates the throttle position of the engine (not shown) based on the output signal from the controller 6.

8: Brake force control means Normally, it is composed of a hydraulic valve or the like, and operates the deceleration force (brake force) based on the output signal from the controller 6.

The engine output operating means 7 and the braking force control means 8 constitute a vehicle speed control means.

The operation of the above embodiment will be described below with reference to the flow charts of the control programs shown in FIGS. These control programs are executed by the controller 6
It is stored in the internal ROM 62 and is executed by the CPU 64 at a predetermined constant cycle. Also, the CPU 64
Is initialized by turning on an ignition key (not shown) or the like, a set flag, a brake flag, and a braking flag which will be described later are turned off.

Control program step S1 in FIG . 2 judges the state of the set flag indicating whether or not speed control is being executed, and if ON, proceeds to step S4.
If it is FF (when the ignition key is ON), step S
Proceed to 2.

Step S2: If the operation start detecting means (set switch) 3 is turned on by the driver's operation, the process proceeds to step S3 and is turned off (not operated).
If so, the process proceeds to step S8.

Step S3: The set flag is turned on and the process proceeds to step S4.

Step S4: It is judged from the output of the brake pedal depression detecting means 5 whether or not the driver depresses the brake pedal. As a result, if it is not depressed, the process proceeds directly to step S6. If it is depressed, the process proceeds to step S5.

Step S5: The brake flag (a flag indicating whether or not the brake pedal is depressed during speed control) is turned on, and then the process proceeds to step S6.

Step S6: The operation release detecting means 4 detects whether or not the driver is performing a predetermined speed control release operation (shift lever position change, cancel switch ON operation, etc.), and the release operation is being performed (YES. ), The process proceeds to step S7, and if not operated (NO), the process proceeds to step S10. In the present invention, unlike the conventional,
The release operation in step S6 does not include the depression of the brake pedal.

Step S7: The set flag is turned off and the process proceeds to step S8.

Step S8: Turn off the brake flag and proceed to step S9.

Step S9: Release the speed control shown in FIG.
The throttle opening, braking force, and gear position are determined according to the driving operation of the driver. A known normal shift map is used as the shift map of the automatic transmission at this time.

Step S10: Similar to step S4,
At present, it is determined whether or not the driver depresses the brake pedal, and if so, the process proceeds to step S11 to determine whether or not to release the speed control in consideration of the risk of a rear-end collision. If not, the process proceeds to step S12.

Step S11: It is determined from the braking flag whether the current control state is the braking force control state. This braking flag is turned on / off in FIG.

As a result, when it is found that the braking flag is ON, the vehicle is decelerating and there is a risk of a rear-end collision with the preceding vehicle. Therefore, the routine normally proceeds to step S20 to continue the speed control (deceleration control). Do not reduce the deceleration force. If the braking flag is OFF, there is no danger of a rear-end collision, and therefore the process proceeds to steps S7 to S9 to cancel the speed control as in the conventional case.

Step S12: If the state of the brake flag is judged to be OFF, the process proceeds to step S20. this is,
This is a normal flow indicating that the driver never presses the brake pedal during speed control.

If the brake flag is ON, it means that the driver once depresses the brake pedal during speed control and then releases (releases) it. Therefore, the process proceeds to steps S7 to S9 to cancel the speed control.

Step S20: Speed control as shown in FIG. 3 is executed.

The subroutine of FIG . 3 (step S2 of FIG. 2)
Details of 0) Step S21: The current vehicle speed V is read by the vehicle speed detecting means 2.

Step S22: The inter-vehicle distance detecting means 1 reads the current inter-vehicle distance D.

Step S23: The current vehicle speed V detected by the vehicle speed detecting means 2 is read.

Step S24: The target inter-vehicle distance Dt estimated to be suitable for traveling at the current vehicle speed V is calculated as follows. For example, it can be obtained from an equation such as Dt = A * V + B (A and B are constants) or a relation table between V and Dt.

Alternatively, in order for the driver to set an arbitrary target inter-vehicle distance Dt, a volume (knob), a rotary switch or the like is used, and a mechanism such as a clock time adjusting mechanism capable of adjusting the numbers is used. Alternatively, the target inter-vehicle distance Dt may be set in the controller 6.

Step S25: Compare the current inter-vehicle distance D with the target inter-vehicle distance Dt, and if Dt> D (that is, if the preceding vehicle exists within the range of the target inter-vehicle distance), set the inter-vehicle distance to the target inter-vehicle distance. The process proceeds to step S26 to control the inter-vehicle distance to the value of the distance.

On the contrary, if Dt ≦ D (that is, if no preceding vehicle exists within the range of the target inter-vehicle distance), the process proceeds to step S27 to control the vehicle speed to the value of the target vehicle speed.

Step S26: How much acceleration / deceleration should be performed with respect to the current vehicle speed V, that is, the change amount ΔV of the vehicle speed at the present time is obtained. The value of ΔV is obtained based on a value such as (Dt-D) which is the difference between the target inter-vehicle distance and the current inter-vehicle distance D.

For example, ΔV = X * (Dt-D) + Y
(X and Y are constants).

In this case, since the target inter-vehicle distance Dt is larger than the current actual inter-vehicle distance D and the vehicle is approaching the preceding vehicle, ΔV has a negative value.

Step S27: Similar to step S26, the current change ΔV in vehicle speed is obtained. However,
In this case, since Dt ≦ D, it is appropriate to perform constant-speed traveling control instead of inter-vehicle distance control.
It is calculated based on the difference (Vt-V) between the target vehicle speed and the current vehicle speed.

For example, ΔV = α * (Vt-V) + β
(Α and β are constants). In this case, if Vt> V, ΔV takes a positive value and acceleration is required to bring it closer to the target vehicle speed, but if Vt <V, ΔV becomes a negative value, so deceleration to the target vehicle speed is performed. There is a need to.

Step S28: The above step S26,
It is determined whether the speed variation ΔV obtained in S27 is positive or negative, that is, whether deceleration or acceleration is required.

Step S29: As a result of the determination in step S28, when ΔV <0, deceleration control is required, so the braking flag is set to ON.

Step S30: If the result of determination in step S28 is that ΔV <0, acceleration control is required, so the braking flag is turned off.

Step S31: Step S26 or S2
The throttle operation amount Δθ is obtained based on the vehicle speed change ΔV obtained in Step 7. For example, Δθ = K1 * ΔV + K2
It can be calculated from an equation such as (K1 and K2 are constants) or a relation table between ΔV and Δθ.

Step S32: Step S26 or S2
The brake operation amount ΔP is obtained based on the vehicle speed change ΔV obtained in Step 7. For example, ΔP = K3 * ΔV + K4 (K
3, K4 is a constant) or a relational table between ΔV and ΔP.

Here, the constants and relational tables in the equations in each step can be obtained in advance by experiments or the like.

The throttle amount and the braking force (corresponding to the integrated values of Δθ and ΔP) do not become positive values at the same time. That is, only the throttle is operated with the braking force "0" during acceleration, and only the braking force is operated with the throttle amount "0" during deceleration.

The speed control algorithm described above shows a simple example in which the constant speed traveling control and the inter-vehicle distance control are combined, but various conventional techniques can be applied as described above.

[0066]

As described above, according to the vehicle speed control device of the present invention, the brake operation is not included in the release operation when the deceleration control is performed even when the depression of the brake pedal is detected. Since it is configured to release the operation for the first time until the release is detected by the release detection means or when the release of the brake pedal is detected, even if the driver depresses the brake pedal during execution of speed control, Since there is a risk of a rear-end collision, the rear-end collision is avoided by not releasing the deceleration control.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a vehicle speed control device according to the present invention.

FIG. 2 is a flowchart of a control program executed by a controller used in the vehicle speed control device according to the present invention.

FIG. 3 is a flowchart of a control program for executing a “execution of speed control” subroutine in FIG.

[Explanation of symbols]

 1 inter-vehicle distance detecting means 2 vehicle speed detecting means 3 actuation start detecting means 4 actuation release detecting means 5 brake pedal depression detecting means 6 controller 7 engine output operating means 8 braking force operating means In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (3)

[Claims] 1. A means for detecting an actual inter-vehicle distance from a vehicle in front, a vehicle speed detecting means, a vehicle speed control means, an operation start detecting means, an operation release detecting means, and an operation start by the operation start detecting means is detected. The target inter-vehicle distance corresponding to the vehicle speed is calculated until the operation is released by the operation release detecting means, and the change in vehicle speed is calculated based on the difference between the calculated target inter-vehicle distance and the actual inter-vehicle distance. A controller for controlling the vehicle speed control means according to the obtained vehicle speed change amount, and a vehicle speed control device capable of constant speed traveling control and inter-vehicle distance control, wherein the controller detects the brake pedal depression, and the controller is provided. Even when the depression of the brake pedal is detected, when the vehicle speed control means controls the deceleration, the brake operation is not included in the release operation and is operated by the operation release detection means. Speed control apparatus for a vehicle, characterized in that not deactivated until removal is performed. 2. The vehicle according to claim 1, wherein the controller releases the operation when the release of the brake pedal is detected even when the release is not detected by the release detecting means. Speed control device. 3. The vehicle speed control device according to claim 1, wherein the target inter-vehicle distance is set by the target inter-vehicle distance setting means instead of being calculated from the vehicle speed by the controller.