JPH1128947A - Speed control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To grasp a car speed control condition at real time without simultaneously performing display of a vehicle-to-vehicle distance and a display of a set car speed in a speed control device for a vehicle having a vehicle-to-vehicle distance control (follow-up running control) function. SOLUTION: A car speed at the time of starting speed control by a device is memorized as a set car speed, a vehicle-to-vehicle distance cruise mode to keep a vehicle-to-vehicle distance at a constant value is set when a preceding vehicle is detected, a brake actuation prohibiting condition is set when the preceding vehicle is not detected, a target car speed converted from the vehicle- to-vehicle distance just before is kept for a specified time, a car speed holding/ acceleration cruise mode to gradually accelerate the target car speed to the set car speed is set after the specified time is passed, or within the specified time when the will of acceleration of a driver is detected, a set car speed cruise mode to fix the set car speed is set when the target speed becomes the set car speed in either cruise mode, and a cruise mode display part 9 to display the cruise mode is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

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.

[0001]

2. Description of the Related Art In order to improve easy drive performance,
Recently, many vehicles equipped with a speed control device that performs a constant speed traveling (auto cruise) function that controls the vehicle to run at a constant speed, but this speed control device operates the accelerator pedal by the driver. The engine output is controlled by adjusting the throttle opening and the like so that the speed of the own vehicle can be kept constant without performing the operation.

However, with this speed control device, there is a risk that the vehicle will collide when the vehicle ahead is slower than the own vehicle. Therefore, recently, a number of devices have been developed which detect the inter-vehicle distance to a vehicle ahead and maintain a predetermined safe inter-vehicle distance.

For example, when the inter-vehicle distance between the preceding vehicle and the host vehicle detected by the inter-vehicle distance detecting means is equal to or more than a predetermined value, the vehicle travels at a constant speed at a target vehicle speed. There is well known a vehicle speed control device in which the control means controls the engine output operation means and the brake operation means so as to keep the distance at the constant value.

[0004] The applicant of the present invention has previously described Japanese Patent Application No.
No. 3002, it is an object of the present invention to prevent unnecessary acceleration from being started even if the preceding vehicle is lost or the inter-vehicle distance suddenly increases, and to prevent frequent repetition of the operation of returning to the set vehicle speed. A vehicle speed control device has been disclosed. This will be described below.

FIG. 3 is a block diagram showing an embodiment of a vehicle speed control device disclosed in Japanese Patent Application No. 8-73002. Each block will be described in turn.

1: Inter-vehicle distance detector Means comprising , for example, an FM-CW radar, a laser radar, an ultrasonic sensor, etc., for detecting a relative speed and an inter-vehicle distance with respect to a vehicle ahead (an object ahead).

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

[0008] 3: Operation start detection means Normally, a digital switch (such as a push switch equivalent to an auto cruise set switch) is configured, and this switch is turned on from an OFF state by a driver's operation.
The speed control is started when the state is detected.

[0010] 4: Operation release detecting means This means detects the case where the driver operates a brake pedal or a predetermined switch (such as a cancel switch) and releases the speed control.

5: Controller An input port 51 for reading an input signal from each of the above-described units 1 to 4, a ROM 52 in which programs and fixed control parameters shown in FIGS. That temporarily stores the control parameters of the
The control means includes an AM 53, a CPU 54 for performing arithmetic processing based on the above-described program, and an output port 55 for sending an output signal to each operation means described later.

6: Engine output operation means Usually constituted by a motor, a valve and the like, and operates the engine output by operating the throttle position of an engine (not shown) based on an output signal from the controller 5.

7: Brake operating means Usually constituted by a hydraulic valve, a magnetic valve, or the like, and operates a deceleration force (braking force) by a service brake, an exhaust brake, a retarder, or the like based on an output signal from the controller 5. .

8: Acceleration Will Detecting Means This is constituted by an auto cruise resume switch, an accelerator pedal switch, etc., and detects acceleration intention by operating when the driver performs an acceleration operation.

Next, the operation of the embodiment shown in FIG. 3 will be described with reference to the flowcharts of the control programs shown in FIGS. These control programs are stored in the ROM 52.
, And is executed by the CPU 54 at predetermined regular intervals. In addition, when an ignition key (not shown) is turned on or the like, a flag described later is turned off when the controller 5 is initialized.

FIG . 4 shows a control program step S1: the CPU 54 executes the definition of each variable, the port,
Initialize a device such as a timer.

Step S2: The CPU 54 determines whether or not a speed control start condition is satisfied. If the condition is satisfied, the process proceeds to step S3, and if not, the process proceeds to step S16. The speed control start conditions are as follows. You are not stepping on the brake. The clutch is not depressed (for manual transmission vehicles). The position of the shift lever switch is D, D3, etc. (in the case of an automatic transmission car). The vehicle speed is higher than the control minimum vehicle speed (for example, 40 km / h or higher). When the set switch is pressed and then released. When one second or more has passed since the main switch was turned on.

Step S3: When the condition (1) in step S2 is satisfied, the CPU 54 stores the vehicle speed immediately after the operation of the device as the set vehicle speed Ss. In the future, control is performed so that the vehicle speed does not become higher than the set vehicle speed Ss regardless of whether the vehicle is cruising between vehicles or cruising at a constant vehicle speed.

Step S4: The CPU 54 determines whether or not the speed control release condition is satisfied. If the condition is satisfied, the process proceeds to step S16, and if not, the process proceeds to step S6.
The speed control release condition is as follows. Press the brake pedal. Step on the clutch (for manual transmission vehicles). Operate the release switch. When the vehicle speed is equal to or lower than the control minimum vehicle speed (for example, 35 km / h) (except when the brake is operating).

Step S5: When the speed control release condition in step S4 is not satisfied, the CPU 54
An inter-vehicle distance and a relative speed with respect to a preceding vehicle are obtained from the inter-vehicle distance detecting means 1.

Step S6: The CPU 54 reads the vehicle speed of the own vehicle from the vehicle speed detecting means 2. It is preferable to use the vehicle speed signal from which noise has been removed by filtering or the like.

Step S7: The CPU 54 calculates a target vehicle speed. The details are shown in the flowchart of FIG. 5, which will be described later.

Step S8: The CPU 54 calculates a brake timing. When performing inter-vehicle distance control, an equation for calculating a timing at which an alarm is generated is generally given as follows.

[0023]

(Equation 1)

That is, the brake inter-vehicle distance is obtained by the same concept with reference to the equation (1), and the brake operation is performed when the actual inter-vehicle distance becomes equal to or less than the brake inter-vehicle distance as described later.

Step S9: The CPU 54 proceeds to step S9.
The brake operation flag set in step 7 is determined. If the operation flag is ON and the brake can be operated, the process proceeds to step S10. If the operation flag is OFF, the process proceeds to step S13.

Step S10: The CPU 54 determines whether or not a brake operating condition is satisfied. Whether or not the brake operation condition is satisfied indicates whether or not the actual inter-vehicle distance is smaller than the warning inter-vehicle distance calculated in step S8. If the condition is the brake operation condition, the process proceeds to step S11; otherwise, the process proceeds to step S13.

Step S11: The CPU 54 controls the engine output operation means 6 to close the accelerator and controls the accelerator operation amount to "0".

Step S12: The CPU 54 performs a brake operation. The braking force can be applied, for example, by applying a force proportional to the difference between the actual inter-vehicle distance and the warning inter-vehicle distance.

Step S13: When the brake operation flag is OFF in step S9, or when it is determined that the brake operation condition is not satisfied in step S10, the CPU 54 calculates the accelerator operation amount and performs the engine output operation. The accelerator operation is performed by the means 6. Assuming that the difference between the target vehicle speed and the actual vehicle speed is e, the accelerator operation amount θ can be obtained in the form of PI control by the following equation, for example.

[0030]

Θ = a × ∫e + b × e (2) where a and b are coefficients.

Step S14: The CPU 54 keeps the brake force operating means 7 from operating.

Step S15: The CPU 54 adjusts the main processing time. Here, for example, it is set to 0.1 second.

Step S16: If the control start condition is not satisfied in step S2, or if the release condition is satisfied, the speed control device is released.

The subroutine of FIG . 5 (step S7 of FIG. 4)
The details) Step S20: CPU 54 determines whether or not the preceding vehicle is detected by the presence or absence of an output signal of the inter-vehicle distance detecting means 1 loaded through an input port 51.

Step S21: When the preceding vehicle is not detected in step S20, the CPU 54 turns off the brake operation flag so as not to operate the brake.

Step S22: The CPU 54 determines whether or not immediately after the preceding vehicle is no longer detected.

Step S23: If it is determined in step S22 that immediately after the preceding vehicle is no longer detected, the target vehicle speed Vt1 in the inter-vehicle distance cruise (when the preceding vehicle is detected) one sampling time before the CPU 54 is detected. Is the target vehicle speed Vt2 when the preceding vehicle is not detected.

Step S24: When the CPU 54 determines that it is not immediately after the preceding vehicle is no longer detected in step S22, or after executing step S23,
It is determined whether or not a timer time t after the detection of the preceding vehicle is not longer than the threshold value T. This threshold T is a period necessary to prevent the acceleration from starting. Each time this step is passed, the timer time t is incremented by "1".

Step S25: When the CPU 54 finds that t ≦ T in step S24, the driver sets the resume switch SW as the acceleration intention detecting means 8
Is turned on.

Step S26: When it is found that the switch SW is ON in step S25, or when t> T in step S24,
= T.

Step S27: In order to gradually increase the target vehicle speed, the CPU 54 sets the target vehicle speed Vt2 to a constant "a".
Add.

Step S28: When the switch SW is OFF in step S25, or in steps S26 and S26
After step 27, Vt = Vt2 to maintain the final target vehicle speed Vt.

Step S29: It is determined whether or not the target vehicle speed Vt is equal to or higher than the set vehicle speed Ss.

Step S30: In step S29, Vt
When it is found that ≧ Ss, Vt = Ss, and the vehicle speed is limited to the set vehicle speed Ss.

Step S31: When the preceding vehicle is detected in step S20, the brake operation flag is turned on, and the brake operation is enabled even under the brake braking condition.

Step S32: Since the preceding vehicle has been detected in step S20, the timer time t indicating the elapsed time from losing sight of the preceding vehicle is cleared.

Step S33: The target vehicle speed Vt is calculated. This target vehicle speed Vt can be obtained by the following equation.

## EQU00003 ## Target vehicle speed Vt1 = inter-vehicle distance D.times.3.6.times.k Equation (3)

The relationship of this equation is obtained by converting the inter-vehicle distance into a target vehicle speed. If k = 1/2, for example, a graph as shown in FIG. 6 is obtained. Approximately 28m at 50km / h,
At a speed of 100 km / h, the vehicle is controlled so as to maintain a headway of about 55 m. However, in the above equation (2), since the convergence to the constant vehicle speed is poor, the calculation may be performed in consideration of the relative speed with respect to the preceding vehicle.

Step S34: The target vehicle speed Vt1 determined in step S33 is set as the target vehicle speed Vt in the above-described step S34.
Go to 29.

The progress of such speed control will be described with reference to FIG. It is assumed that speed control is performed while maintaining the inter-vehicle distance B following the preceding vehicle speed A1, and if the preceding vehicle loses track due to lane change at that time, the target vehicle speed immediately before that is maintained for a certain period (T). .

After this period has elapsed, the target vehicle speed is gradually increased during the period, and when the vehicle speed reaches the set vehicle speed Ss (see step S2), a period in which the set vehicle speed Ss is set as the target vehicle speed is started.

During these periods, the throttle opening changes as shown in graph C.

In this way, the actual vehicle speed at the start of the speed control is stored as the set vehicle speed, and when the preceding vehicle cannot be detected, the target vehicle speed converted from the immediately preceding inter-vehicle distance is held for a certain period of time and the brake is applied. The operation is prohibited, and the target vehicle speed is gradually increased to the set vehicle speed after the lapse of the predetermined time, thereby preventing unnecessary acceleration on a curved road or the like.

[0054]

SUMMARY OF THE INVENTION The aforementioned Japanese Patent Application No. 8-73 is disclosed.
The acceleration intention detecting means used in No. 002 detects the operation of the resume switch by the driver and the like.

For this reason, it is difficult for the driver to determine whether or not the control state at that time can be accelerated by the acceleration intention detecting means.

To cope with this, an example of displaying the following distance to the driver is as follows.
0 ”, when the preceding vehicle is not detected And so on.
The display example of the set vehicle speed is “100” when the set vehicle speed is 100 km / h, and “100” when the vehicle speed is not set. "Etc. may be displayed.

In this way, the driver can display, for example, the inter-vehicle distance display of “ 30 ” and the detected vehicle speed of 60
Since it can be recognized that the vehicle speed is equal to or less than the set vehicle speed “ 100 ” (Km / h) at Km / h, it can be seen that the vehicle can be gradually accelerated to the set vehicle speed by the acceleration intention detecting means.

However, in such a display method,
There was a problem that it took time to grasp the state, and both the display of the distance between vehicles and the display of the set vehicle speed had to be performed simultaneously.

Accordingly, it is an object of the present invention to provide a vehicle speed control device capable of grasping a vehicle speed control state in real time without simultaneously displaying both the inter-vehicle distance and the set vehicle speed.

[0060]

In order to achieve the above-mentioned object, according to the present invention, a vehicle speed detected by a vehicle speed detecting means at the start of speed control of the apparatus is stored as a set vehicle speed.
When the preceding vehicle is detected by the detection result of the following distance detecting means, the following distance cruise mode is set to keep the following distance at the constant value. When the preceding vehicle is not detected, the brake operation is prohibited and the immediately preceding vehicle is set. The target vehicle speed converted from the distance is held for a predetermined period of time, and after the predetermined period of time has elapsed or even within the predetermined period of time, when the driver's intention to detect acceleration is detected, the target vehicle speed is reduced to the set vehicle speed. The control means includes an engine output operation means and a vehicle speed holding / acceleration cruise mode for gradually accelerating, and in any cruise mode, a set vehicle speed cruise mode for fixing the vehicle speed to the set vehicle speed when the target vehicle speed reaches the set vehicle speed. In a vehicle speed control device for controlling a brake operation means, the control means is currently aware of the It is obtained by characterized by providing a cruise mode display unit for displaying the loose mode.

That is, in the present invention, the control means performs the normal inter-vehicle distance control (inter-vehicle distance cruise mode) when the preceding vehicle is detected, and when the preceding vehicle is lost, the vehicle speed at that time is set as the target vehicle speed. The time is maintained, and after the fixed time has elapsed, when the speed control of the device is started (at the start of inter-vehicle distance control or constant speed traveling control)
The vehicle speed is controlled by controlling the engine output operation means and the brake operation means so as to gradually accelerate the target vehicle speed toward the set vehicle speed with the vehicle speed set as the set vehicle speed (vehicle speed holding / acceleration cruise mode).

As a result, unnecessary acceleration on a curved road or the like can be prevented.

Alternatively, there is a case where the driver wants to accelerate by himself. In consideration of such a state, the control means also determines whether the acceleration intention is detected by the driver's acceleration intention detection means. The target vehicle speed is gradually accelerated to the set vehicle speed immediately (vehicle speed holding / acceleration cruise mode).

In any of the cruise modes, when the target vehicle speed reaches the set vehicle speed, the set vehicle speed cruise mode is fixed. .

Each of these cruise modes is recognized by the control means and displayed on the cruise mode display.

Therefore, there is no need to separately provide these cruise mode display units, and the driver can grasp the current vehicle speed control state in real time, so that it is easy to determine whether or not the vehicle can be accelerated by the acceleration intention detecting means. I can judge.

[0067]

FIG. 1 shows an embodiment of a vehicle speed control apparatus according to the present invention. In this embodiment and the conventional example shown in FIG. This is a new point. The set vehicle speed display section 9 is connected to the output port 55 of the controller (control means) 5 and may be any type that can be numerically displayed by, for example, a liquid crystal or a light emitting diode.

FIG. 2 is a flowchart showing the operation of the embodiment of the present invention shown in FIG. 1. The difference between this flowchart and the flowchart according to the conventional example shown in FIG. S41 is inserted between steps S28 and S29, step S42 is inserted between steps S34 and S29, and step S43 is inserted as the last step after step S30.

Hereinafter, these new steps S41 to S41
Only the operation of Step 43 will be described, and other steps S1
S15 and S20 to 30 will not be individually described.

Step S41: After it is determined in step S20 that the preceding vehicle has not been detected based on the detection result of the following distance detecting means 1, steps S21 to S28 are executed.
The vehicle speed holding / acceleration cruise mode is set, and the CPU 54 displays on the cruise mode display section 9 via the output port 55 that the vehicle is currently in the inter-vehicle distance cruise mode.

That is, when the preceding vehicle is not detected, the brake operation is prohibited (step S21).
At the same time, the target vehicle speed converted from the immediately preceding inter-vehicle distance is held for a predetermined time (steps S22 to S24, S25, S
28).

After the predetermined time has elapsed (step S2
4, S26 to S28) or when the driver's intention to detect acceleration is detected (steps S24 to S28) even within the fixed time, the vehicle speed at which the target vehicle speed is gradually accelerated to the set vehicle speed. The display section 9 displays "vehicle speed hold / acceleration cruise" as the hold / acceleration cruise mode.

Step S42: After it is determined in step S20 that the preceding vehicle has been detected based on the detection result of the following distance detecting means 1, and steps S31 to S34 are executed, the vehicle is set to the following distance cruise mode. The mode display section 9 displays that the vehicle is currently in the following distance cruise mode.

That is, the brake operation prohibited state is released (step S31), and the vehicle speed Vt1 is calculated based on the following distance D detected by the following distance detecting means 1 (step S31).
33) Display “inter-vehicle distance cruise” performed on the display unit 9 using the vehicle speed Vt1 as the target vehicle speed Vt.

Step S43: When accelerating in the above-mentioned vehicle speed holding / acceleration cruise mode (step S27) or when accelerating in the inter-vehicle distance cruise mode (step S13 in FIG. 4), the target vehicle speed is set at the start of the speed control of the apparatus. When the vehicle speed reaches the set vehicle speed (at the start of the inter-vehicle distance control or the cruise control), the vehicle speed is fixed to the set vehicle speed (steps S29 and S29).
30).

Then, the CPU 54 displays on the cruise mode display section 9 via the output port 55 that the current vehicle speed is the "set vehicle speed cruise mode".

It should be noted that the result of the determination in step S29 is "N
If it is "O", it is necessary to skip this step S43 so as not to be executed.

Table 1 below shows the display contents of each cruise mode on the display unit 9 and the relationship between the display contents and the effectiveness of the acceleration intention detecting means.

[0079]

[Table 1]

The display colors may be distinguished by a color liquid crystal or the like.

[0081]

As described above, according to the vehicle speed control device according to the present invention, the vehicle speed at the time of starting the speed control of the device is stored as the set vehicle speed, and when the preceding vehicle is detected, the vehicle speed is controlled. The inter-vehicle distance cruise mode in which the distance is maintained at the constant value is set. When the preceding vehicle is not detected, the brake operation is disabled and the target vehicle speed converted from the immediately preceding inter-vehicle distance is maintained for a predetermined time and the predetermined time elapses. After that, or if the driver's intention to accelerate is detected even within the fixed time, the target vehicle speed is set to the vehicle speed holding / acceleration cruise mode in which the target vehicle speed is gradually accelerated to the set vehicle speed. A cruise mode in which the set vehicle speed is fixed at the set vehicle speed when the set vehicle speed is reached, and the cruise mode is displayed. Is provided with the over-de display unit, the following effects can be obtained.

Since the state of the speed control can be known at a glance, it is possible to save the trouble of judging whether or not the acceleration intention detecting means is effective.

Since the trouble of knowing the current control contents can be omitted, no extra burden is imposed on the driver.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one 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 block diagram showing an embodiment of a vehicle speed control device according to Japanese Patent Application No. 8-73002.

FIG. 4 is a flowchart of a control program executed by a controller used in a vehicle speed control device according to Japanese Patent Application No. 8-73002.

FIG. 5 is a flowchart of a control program that executes a subroutine of “target vehicle speed calculation” in FIG. 4;

FIG. 6 is a graph for calculating a target vehicle speed from an inter-vehicle distance used in a vehicle speed control device according to the present invention and Japanese Patent Application No. 8-73002.

FIG. 7 is a graph showing a cruise state in the vehicle speed control device according to Japanese Patent Application No. 8-73002.

[Explanation of symbols]

 1 inter-vehicle distance detection means 2 vehicle speed detection means 3 operation start detection means 4 operation release detection means 5 controller 6 engine output operation means 7 brake operation means 8 acceleration intention detection means 9 cruise mode display section Is shown.

Claims (1)

[Claims] A vehicle speed detected by a vehicle speed detecting means at the start of speed control of the apparatus is stored as a set vehicle speed, and when a preceding vehicle is detected based on a detection result of the following distance detecting means, the inter-vehicle distance is fixed. When the preceding vehicle is not detected, the brake operation is prohibited and the target vehicle speed converted from the immediately preceding vehicle distance is held for a certain period of time, and after the certain time has elapsed or Even if within a certain time, when the driver's intention to accelerate is detected by the driver's intention to accelerate, the target vehicle speed is set to the vehicle speed holding / acceleration cruise mode in which the target vehicle speed is gradually accelerated to the set vehicle speed. When the set vehicle speed is reached, the control means controls the engine so that the set vehicle speed is fixed to the set vehicle speed. In the speed control device for a vehicle that controls a force operating means and brake operating means, the speed control device for a vehicle, characterized in that a cruise mode display unit for displaying the cruise mode in which the control means are currently known by.