JP2016185744A - Vehicle speed control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle speed control device that enables smooth traveling even when accuracy of an accelerator operation performed by a driver is low.SOLUTION: A vehicle speed control device includes: accelerator operation means 111 for performing an accelerator operation by changing a position of an operation member by a driver; and driving force control means 110 for controlling driving force of a vehicle in accordance with the position of the operation member. The driving force control means is configured to control the driving force so as to maintain current vehicle speed when the position change amount from a reference position of the operation member is lower than a predetermined vehicle speed change threshold value and control the driving force so as to change the vehicle speed at a predetermined change rate when the position change amount from the reference position of the operation member is equal to or higher than the predetermined vehicle speed change threshold value.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a vehicle speed control device that controls the traveling speed of a vehicle such as an automobile.

Conventionally, driving torque of a vehicle such as an automobile is controlled by an accelerator operation of a driver.
In addition, for the purpose of reducing the burden on the driver, a technique for controlling engine output or the like so as to maintain the vehicle speed is known (see, for example, Patent Documents 1 and 2).

JP 2004-050904 A JP 2010-241310 A

  By the way, when controlling torque according to the driver's accelerator operation, if the accuracy of the driver's accelerator operation is low, the vehicle speed greatly fluctuates even though the driver intends to travel at a constant vehicle speed.

  In view of the above-described problems, an object of the present invention is to provide a vehicle speed control device that can smoothly travel even when the driver's accelerator operation accuracy is low.

The present invention solves the above-described problems by the following means.
The invention according to claim 1 includes accelerator operating means for performing an accelerator operation by changing the position of the operating member by a driver, and driving force control means for controlling the driving force of the vehicle in accordance with the position of the operating member. In the vehicle speed control device, the driving force control means controls the driving force so as to maintain the current vehicle speed when the position change amount of the operation member from the reference position is less than a predetermined vehicle speed change threshold. The vehicle speed control device is configured to control the driving force so that the vehicle speed changes at a predetermined rate of change when a position change amount of the operation member from the reference position is equal to or greater than the vehicle speed change threshold value. .
According to this, even if the driver's unintended variation or shake occurs at the position of the operation member of the accelerator operation means, the current vehicle speed is maintained unless the position change amount from the reference position exceeds the vehicle speed change threshold value. Therefore, even if the driver's accelerator operation accuracy is low, useless acceleration / deceleration can be suppressed, and smooth driving can be performed to improve driving comfort and fuel efficiency.

The invention according to claim 2 is the vehicle speed control device according to claim 1, wherein the vehicle speed change threshold is set so as to increase as the vehicle speed decreases.
According to this, the driving wheel torque becomes relatively large, and the vehicle speed fluctuation due to the variation in the accelerator operation tends to become abrupt. Can be made easy.

The invention according to claim 3 is the vehicle speed control device according to claim 1 or 2, wherein the rate of change when the vehicle speed is changed is set larger on the acceleration side than on the deceleration side. .
According to this, it is possible to improve the acceleration of the vehicle when the driver performs the accelerator operation with the intention of accelerating, and to realize traveling that is faithful to the driver's intention.

According to a fourth aspect of the present invention, in the vehicle speed control device according to any one of the first to third aspects, the vehicle speed change threshold is set smaller on the acceleration side than on the deceleration side. is there.
According to this, on the acceleration side, the vehicle speed change threshold can be easily exceeded, and the driver's intention to accelerate can be easily reflected in the actual acceleration.
On the other hand, on the deceleration side, it is difficult to exceed the vehicle speed change threshold value, and it is possible to prevent unintended deceleration by the driver who is concerned about causing a rear-end collision or traffic jam.

The invention according to claim 5 is provided with a preceding vehicle detecting means for detecting a relative distance of the preceding vehicle from the own vehicle, and the vehicle speed change threshold is corrected so as to become smaller as the preceding vehicle approaches the own vehicle. The vehicle speed control device according to any one of claims 1 to 4, wherein the vehicle speed control device is a vehicle speed control device.
The invention according to claim 6 is provided with preceding vehicle detection means for detecting a relative distance of the preceding vehicle from the own vehicle, and the rate of change when changing the vehicle speed is in accordance with the approach of the preceding vehicle to the own vehicle. The vehicle speed control device according to any one of claims 1 to 4, wherein the vehicle speed control device is corrected so as to increase.
According to each of these inventions, when the inter-vehicle distance from the preceding vehicle is small, the vehicle speed can be easily changed and the inter-vehicle distance can be easily adjusted.

  As described above, according to the present invention, it is possible to provide a vehicle speed control device capable of smooth running even when the driver's accelerator operation accuracy is low.

It is a block diagram which shows the structure of the power train of the vehicle which has the Example of the vehicle speed control apparatus to which this invention is applied. It is a flowchart which shows operation | movement of the vehicle speed control apparatus of an Example. It is a schematic diagram which shows the relationship between the operation amount of the accelerator pedal in the speed control control mode of the vehicle speed control apparatus of an Example, and the state of a vehicle.

  An object of the present invention is to provide a vehicle speed control device capable of smooth running even when the driver's accelerator operation accuracy is low. When the vehicle speed is less than a predetermined vehicle speed change threshold, the current vehicle speed is maintained, and when it is equal to or higher than the vehicle speed change threshold, the driving force is controlled so as to accelerate or decelerate at a predetermined vehicle speed change rate.

Embodiments of a vehicle speed control device to which the present invention is applied will be described below.
The vehicle speed control device according to the embodiment is provided, for example, in an automobile such as a passenger car using an engine as a driving power source, and controls the vehicle speed by adjusting the driving force according to an accelerator pedal operation by a driver.

FIG. 1 is a block diagram illustrating a configuration of a power train of a vehicle having a vehicle speed control device according to an embodiment.
As shown in FIG. 1, the vehicle includes an engine 10, a torque converter 20, a forward / reverse switching unit 30, a variator 40, a front differential 50, a rear differential 60, a transfer clutch 70, an engine control unit 110, a transmission control unit 120, and behavior control. A unit 130, an environment recognition unit 140, and the like are provided.

The engine 10 is an internal combustion engine used as a driving power source for a vehicle.
As the engine 10, for example, a 4-stroke gasoline engine can be used.
The engine 10 has its main body and auxiliary devices controlled by the engine control unit 110, and a torque control control mode for generating an output torque corresponding to a required torque that is normally set based on the accelerator operation of the driver is executed.
In addition, the engine output is controlled so that the actual vehicle speed follows the target vehicle speed set according to the accelerator operation under predetermined driving conditions such as driving on a high-standard road such as an expressway at a substantially constant speed. A speed control control mode is executed.
The speed control control mode will be described in detail later.

The torque converter 20 is a fluid coupling that transmits the output of the engine 10 to the forward / reverse switching unit 30.
The torque converter 20 has a function as a starting device capable of transmitting engine torque from a state where the vehicle is stopped.
The torque converter 20 includes a lockup clutch (not shown) that is controlled by the transmission control unit 120 and directly connects the input side (impeller side) and the output side (turbine side).

The forward / reverse switching unit 30 is provided between the torque converter 20 and the variator 40, and a forward mode in which the torque converter 20 and the variator 40 are directly connected, and a reverse mode in which the rotational output of the torque converter 20 is reversed and transmitted to the variator 40. The mode is switched according to a command from the transmission control unit 120.
The forward / reverse switching unit 30 includes, for example, a planetary gear set.

The variator 40 is a transmission mechanism that continuously changes the rotational output of the engine 10 transmitted from the forward / reverse switching unit 30.
The variator 40 is, for example, a chain type continuously variable transmission (CVT) having a primary pulley 41, a secondary pulley 42, a chain 43, and the like.
The primary pulley 41 is provided on the input side of the variator 40 during driving of the vehicle, and receives the rotation output of the engine 10.
The secondary pulley 42 is provided on the output side of the variator 40 when the vehicle is driven.
The secondary pulley 42 is rotatable about a rotation axis adjacent to the primary pulley 41 and parallel to the rotation axis of the primary pulley 41.
The chain 43 is formed in an annular shape, wound around the primary pulley 41 and the secondary pulley 42, and transmits power between them.
The primary pulley 41 and the secondary pulley 42 each have a pair of sheaves that sandwich the chain 43, and the effective diameter is changed steplessly by changing the interval between the sheaves according to the shift control by the transmission control unit 120. It is possible.

The front differential 50 transmits the driving force transmitted from the variator 40 to the left and right front wheels.
The front differential 50 includes a final reduction gear and a differential mechanism that absorbs the difference in rotational speed between the left and right front wheels.
The variator 40 and the front differential 50 are substantially directly connected.

The rear differential 60 transmits the driving force transmitted from the variator 40 to the left and right rear wheels.
The rear differential 60 includes a final reduction gear and a differential mechanism that absorbs the difference in rotational speed between the left and right rear wheels.

The transfer clutch 70 is provided in the middle of the rear wheel driving force transmission mechanism that transmits the driving force from the variator 40 to the rear differential 60, and connects or disconnects the power transmission path therebetween.
The transfer clutch 70 is, for example, a hydraulic or electromagnetic wet multi-plate clutch capable of continuously changing the fastening force (transmission torque capacity) at the time of connection.
The fastening force of the transfer clutch 70 is controlled by the transmission control unit 120.
The transfer clutch 70 can adjust the drive torque distribution of the front and rear wheels by changing the fastening force.
The transfer clutch 70 reduces (opens) the fastening force when it is necessary to allow a difference in rotational speed between the front and rear wheels when the vehicle is turning, when brake antilock control, vehicle behavior control, or the like is performed. The rotational speed difference is absorbed by slipping.

The engine control unit 110 controls the engine 10 and its auxiliary equipment in an integrated manner.
The engine control unit 110 controls the output torque of the engine 10 by controlling various parameters such as the throttle opening, fuel injection amount and injection timing, ignition timing, supercharging pressure, valve timing, and EGR amount of the engine 10. It has a function.
The engine control unit 110 functions as driving force control means in the present invention in cooperation with the transmission control unit 120.
The engine control unit 110 is input with a depression amount (accelerator opening) of an accelerator pedal 111 to which a driver inputs an accelerator operation. The accelerator pedal 111 is movable within a predetermined stroke range according to the driver's stepping operation, and includes a position encoder that detects the current position (stepping amount).
The engine control unit 110 controls the torque control mode for controlling the actual torque of the engine 10 to approach the driver request torque set according to the depression amount of the accelerator pedal 111, and the engine 10 so as to maintain the set vehicle speed. It has a speed control control mode in which the set vehicle speed can be changed by operating the accelerator pedal 111 while controlling torque and the like.
The speed control control mode will be described in detail later.

The transmission control unit 120 comprehensively controls the lock-up clutch, the forward / reverse switching unit 30, the variator 40, the transfer clutch 70, and the like of the torque converter 20.
The transmission control unit 120 cooperates with the engine control unit 110 to cooperatively control the variator 40 and the like, and when the target driving force (driving wheel torque) cannot be obtained only by adjusting the output of the engine 10, the transmission ratio It responds by change etc.

The behavior control unit 130 is a fluid hydraulic pressure supplied to a wheel cylinder of each wheel in a hydraulic service brake (not shown) of the vehicle based on the state (stroke, pedaling force) of the brake pedal 131 to which the driver inputs a brake operation. Is to control the overall.
The behavior control unit 130 has a vehicle speed sensor 132 for detecting the wheel speed of each wheel, and periodically reduces the wheel cylinder hydraulic pressure of the wheel in which wheel lock or its sign is detected during braking, so that the normal rotation state Anti-lock control to recover.
In addition, the behavior control unit 130 performs behavior control that generates a yaw moment in a direction that suppresses the behavior by generating a braking force difference between the left and right wheels when a vehicle behavior in an understeer state or an oversteer state is detected.

The environment recognition unit 140 recognizes an object, a lane, and the like ahead of the host vehicle by the stereo camera 141.
For example, the stereo camera 141 has a pair of cameras arranged in the vehicle width direction in the vicinity of the upper end of the windshield.
The environment recognition unit 140 can detect the relative position of each subject included in the image with respect to the subject vehicle by performing known stereo image processing on the image data sequentially output by the left and right cameras of the stereo camera 141.
Further, the environment recognition unit 140 calculates the relative speed of the subject with respect to the host vehicle based on the transition of the relative position of the subject.
For example, the environment recognition unit 140 can calculate a distance and a relative speed to a preceding vehicle that travels in front of the host vehicle in the same direction as the host vehicle on the travel lane of the host vehicle.

Each of these units includes an information processing means such as a CPU, a storage means such as a RAM and a ROM, an input / output interface, and a bus for connecting them.
These units communicate with each other via, for example, a CAN communication system which is a kind of in-vehicle LAN system, and can transmit information necessary for control.

Hereinafter, the operation of the vehicle speed control device of the above-described embodiment will be described.
FIG. 2 is a flowchart showing the operation of the vehicle speed control apparatus of the embodiment.
This flow is executed sequentially during normal driving of the vehicle.
Hereinafter, the steps will be described step by step.

<Step S01: Speed Control Control Start Condition Determination>
The engine control unit 110 acquires information on the vehicle speed detected by the vehicle speed sensor 132 from the behavior control unit 130.
The engine control unit 110 determines that the current vehicle speed is equal to or higher than a predetermined value set in consideration of, for example, traveling on a high-standard road, and the difference between the average vehicle speed in the past predetermined period (for example, several minutes) and the current vehicle speed. Is within a predetermined range set in advance (when it is considered that the change in vehicle speed is sufficiently small and the driver intends to drive at a constant speed), the process proceeds to step S02, and in other cases, the process of step S01 repeat.

<Step S02: Start of speed control control>
The engine control unit 110 ends the torque control control mode for setting the driver request torque from the depression amount of the accelerator pedal 111, and starts the speed control control mode for maintaining the vehicle speed set according to the depression amount of the accelerator pedal 111. .
In the speed control control mode, the position of the accelerator pedal 111 at the load opening (ROAD LOAD; hereinafter abbreviated as R / L) that is the accelerator opening required to maintain the current vehicle speed is used as a reference position. This is a control mode in which the vehicle speed is changed based on the position change amount (depression amount, return amount) of the accelerator pedal 111 from the opening degree.

The R / L opening is the opening of the accelerator pedal 111 in which the torque in the drive wheels is in balance with the running resistance of the vehicle (maintains a constant vehicle speed) in the torque control control mode.
The R / L opening is acquired from a preset map with the vehicle speed and gradient resistance as axes, for example. That is, the R / L opening is a value that varies depending on the vehicle speed and the gradient.
The gradient resistance can be acquired from the transmission control unit 120 or the like, for example.
In setting the R / L opening, in addition to the vehicle speed and gradient resistance, traveling resistance such as rolling resistance and air resistance may be considered. The rolling resistance and air resistance can be experimentally obtained in advance in accordance with the driving state of the vehicle such as the vehicle speed and the load capacity.
Further, when the vehicle has a cruise control function, the throttle opening corresponding to the target air amount (intake amount necessary for the speed to be maintained) used in the cruise control control may be set as the R / L opening. Good.
During execution of the speed control control mode, the driver may be notified by, for example, displaying an instrument panel.
Proceed to step S03.

<Step S03: Judgment of brake operation>
The engine control unit 110 acquires information related to the state of the brake pedal 131 from the behavior control unit 130.
When the brake operation is performed, the process proceeds to step S06, and when the brake operation is not performed, the process proceeds to step S04.

<Step S04: Determination of accelerator operation speed>
The engine control unit 110 calculates the operation speed (pedal speed) of the accelerator pedal 111 by dividing the change amount of the operation amount (pedal depression amount) of the accelerator pedal 111 within the most recent predetermined period by time.
When the accelerator pedal 111 is operated to the depression side and the absolute value of the accelerator depression speed is equal to or higher than the first operation speed set in advance, the process proceeds to step S06.
Further, when the accelerator pedal 111 is operated to the return side and the absolute value of the accelerator return speed is equal to or higher than the second operation speed set in advance, the process proceeds to step S06.
In other cases, the process proceeds to step S05.
Here, the second operation speed that is the threshold value on the return side is set smaller than the first operation speed that is the threshold value on the depression side. This is for facilitating the determination of the release of the speed control control mode on the return side where the driver's intention to decelerate is estimated.

<Step S05: Determination of accelerator operation amount>
The engine control unit 110 is configured such that the current accelerator opening is equal to or less than a second opening that is a preset step-side speed control (S / C) end threshold, and the return-side S / C is set in advance. It is determined whether or not the opening is equal to or greater than the first opening that is the C end threshold value. If this is satisfied, the process proceeds to step S07, and if not, the process proceeds to step S06.
The first opening and the second opening, which are S / C end thresholds, are set so that the amount of deviation from the R / L opening is greater on both the acceleration side and the deceleration side than the vehicle speed change threshold described later. Is done.
In addition, the S / C end threshold value is changed or corrected depending on the vehicle speed.
For example, when the vehicle speed is low, it is assumed that the vehicle travels in an urban area or the like. Therefore, both the first and second openings are set to R so that the end determination of the speed control control can be easily established when the vehicle speed is high. The accelerator opening range within which the speed control control can be performed can be reduced by changing or correcting in the direction close to the / L opening (decreasing the second opening and increasing the first opening).

<Step S06: End of speed control control>
The engine control unit 110 ends the speed control control mode and returns to the torque control control mode.
Then, it returns to step S01 and repeats subsequent processes.

<Step S07: Determination of Deviation from R / L Opening>
The engine control unit 110 determines whether or not the deviation amount of the current depression amount of the accelerator pedal 111 from the R / L opening is equal to or greater than a predetermined vehicle speed change threshold value.
The vehicle speed change threshold is individually set on the acceleration side (stepping side) and the deceleration side (return side).
The vehicle speed change threshold is set so as to increase as the vehicle speed decreases on both the acceleration side and the deceleration side.
Further, the vehicle speed change threshold is set so that the acceleration side becomes smaller than the deceleration side (exceeds the threshold with a small amount of deviation).
Further, when the environment recognition unit 140 detects a preceding vehicle, the vehicle speed change threshold value is set so as to become smaller (prone to exceed the threshold value) as the preceding vehicle approaches the host vehicle.
If the current depression amount of the accelerator pedal 111 deviates from the R / L opening by the vehicle speed change threshold or more, the process proceeds to step S08, and otherwise, the process proceeds to step S09.

<Step S08: Determination of Deviation Direction with respect to R / L Opening>
The engine control unit 110 detects the direction of deviation of the depression amount of the accelerator pedal 111 with respect to the R / L opening. If the direction is deviated to the acceleration side (depression side), the engine control unit 110 proceeds to step S10 and moves to the deceleration side (return side). If there is a divergence, the process proceeds to step S11.

<Step S09: Maintain vehicle speed>
The engine control unit 110 controls the engine 10 so that the vehicle maintains the current vehicle speed.
Then, it returns to step S03 and repeats the subsequent processes.

<Step S10: Increase in vehicle speed at a predetermined rate of change>
The engine control unit 110 controls the engine 10 so that the vehicle speed increases (accelerates) at a predetermined rate of change (here, it indicates the amount of change in vehicle speed per unit time).
Then, it returns to step S03 and repeats the subsequent processes.

<Step S11: Decrease in vehicle speed at a predetermined rate of change>
The engine control unit 110 controls the engine 10 so that the vehicle speed decreases (decelerates) at a predetermined change rate.
Then, it returns to step S03 and repeats the subsequent processes.

Note that the rate of change of the vehicle speed in steps S10 and S11 is set so that the acceleration side is larger than the deceleration side.
Further, when the environment recognition unit 140 detects a preceding vehicle, the change rate of the vehicle speed is set to increase as the preceding vehicle approaches the host vehicle.

FIG. 3 is a schematic diagram showing the relationship between the operation amount of the accelerator pedal and the state of the vehicle in the speed control control mode of the vehicle speed control device of the embodiment.
As shown in FIG. 3, in the region between the vehicle speed change threshold value (acceleration side) and the vehicle speed change threshold value (deceleration side) with the R / L opening approximately at the center, the operation of the accelerator pedal 111 and the depression amount (position) Regardless, the current vehicle speed is maintained.
When the accelerator pedal 111 is depressed beyond the vehicle speed change threshold (acceleration side), vehicle speed increase (acceleration) is started at a predetermined vehicle speed change rate. When it is depressed to exceed the degree, the speed control control mode is terminated and the torque control control mode is restored.
When the accelerator pedal 111 is returned beyond the vehicle speed change threshold (deceleration side), the vehicle speed starts decreasing at a predetermined vehicle speed change rate, but further exceeds the first opening that is the S / C end threshold. Is returned to the torque control control mode, the torque control control mode is terminated.
When the accelerator pedal 111 is operated so as to exceed the vehicle speed change threshold (acceleration side or deceleration side), and then the deviation from the R / L opening becomes less than the vehicle speed change threshold without ending the speed control control mode. Continue the speed control to maintain the current vehicle speed.

According to the embodiment described above, the following effects can be obtained.
(1) By changing the vehicle speed only when the amount of deviation of the depression amount of the accelerator pedal 111 from the R / L opening is equal to or greater than the vehicle speed change threshold, variations or fluctuations that the driver does not intend in the depression amount of the accelerator pedal 111 Even if this occurs, the current vehicle speed is maintained as long as the position change amount from the R / L opening as the reference position does not exceed the vehicle speed change threshold, so the driver's accelerator operation accuracy is low. However, useless acceleration / deceleration can be suppressed, smooth running is enabled, and driving comfort and fuel efficiency can be improved.
(2) By increasing the vehicle speed change threshold according to the decrease in the vehicle speed, the driving wheel torque becomes relatively large, and the current vehicle speed is maintained during low-speed traveling, where vehicle speed fluctuations due to variations in accelerator operation tend to be abrupt. By enlarging the position range of the pedal 111, it becomes tolerant to the operation of the driver, and constant speed traveling can be facilitated.
(3) By setting the rate of change of the vehicle speed during acceleration / deceleration to be greater on the acceleration side than on the deceleration side, the acceleration of the vehicle when the driver performs the accelerator operation with the intention of acceleration is improved, and the driver's intention Can be driven faithfully.
(4) By setting the vehicle speed change threshold value on the acceleration side to be smaller than that on the deceleration side, the driver's intention to accelerate is easily reflected in the actual acceleration, and the driver who is concerned that it may cause a collision or traffic jam. Unintentional deceleration can be prevented.
(5) The vehicle speed change threshold is reduced according to the approach of the preceding vehicle, and the rate of change of the vehicle speed is increased, thereby facilitating the change of the vehicle speed and facilitating the adjustment of the inter-vehicle distance when the inter-vehicle distance from the preceding vehicle is small. be able to.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the technical scope of the present invention.
(1) The configuration of the vehicle speed control device and the vehicle is not limited to the configuration of the embodiment described above, and can be changed as appropriate.
For example, the vehicle of the embodiment uses an engine as a driving power source. Instead, the vehicle may be an electric vehicle such as a pure EV or FCV using an electric motor as a power source, or a vehicle having a hybrid system of an engine / electric motor. The present invention can also be applied.
(2) In the embodiment, the environment recognition unit recognizes the preceding vehicle using, for example, a stereo camera, but instead of this, a laser radar, a millimeter wave radar, a monocular camera, or the like is used alone or in combination. The preceding vehicle may be recognized by other methods.
Further, the recognition result of such an environment recognition unit may be reflected in the determination of whether or not to start the speed control control.

DESCRIPTION OF SYMBOLS 10 Engine 20 Torque converter 30 Forward / reverse switching part 40 Variator 41 Primary pulley 42 Secondary pulley 43 Chain 50 Front differential 60 Rear differential 70 Transfer clutch 110 Engine control unit 111 Accelerator pedal 120 Transmission control unit 130 Behavior control unit 131 Brake pedal 132 Vehicle speed sensor 140 Environment recognition unit 141 Stereo camera

Claims (6)

An accelerator operating means for operating the accelerator by changing the position of the operating member by the driver;
A vehicle speed control device comprising: driving force control means for controlling the driving force of the vehicle according to the position of the operation member;
The driving force control means controls the driving force so as to maintain the current vehicle speed when the amount of change in position of the operating member from the reference position is less than a predetermined vehicle speed change threshold, and controls the reference of the operating member. The vehicle speed control apparatus, wherein the driving force is controlled so that the vehicle speed changes at a predetermined change rate when a position change amount from a position is equal to or greater than the vehicle speed change threshold value. The vehicle speed control device according to claim 1, wherein the vehicle speed change threshold is set to increase as the vehicle speed decreases. The vehicle speed control device according to claim 1 or 2, wherein the rate of change when changing the vehicle speed is set larger on the acceleration side than on the deceleration side. The vehicle speed control device according to any one of claims 1 to 3, wherein the vehicle speed change threshold is set smaller on the acceleration side than on the deceleration side. A preceding vehicle detecting means for detecting a relative distance of the preceding vehicle from the own vehicle;
The vehicle speed control device according to any one of claims 1 to 4, wherein the vehicle speed change threshold value is corrected so as to decrease as the preceding vehicle approaches the host vehicle. A preceding vehicle detecting means for detecting a relative distance of the preceding vehicle from the own vehicle;
5. The change rate according to claim 1, wherein the rate of change when changing the vehicle speed is corrected so as to increase according to the approach of the preceding vehicle to the host vehicle. Vehicle speed control device.

Images