JPH03132434A - Vehicular travel control device - Google Patents

Abstract

PURPOSE:To enable following travel to various types of vehicles in front such as a passenger car or a big motor lorry so as to improve operability and safety by adjusting the safe spacing distance between the front vehicle and one's own vehicle automatically according to the type of the front vehicle. CONSTITUTION:The travel status such as the spacing distance and relative speed to a vehicle in front, the type of this front vehicle and the speed of one's own vehicle is detected by a means 1. On the basis of the detected relative speed to the front vehicle and speed of one's own vehicle, the safe spacing distance between the front vehicle and one's own vehicle is computed by a means 2. The computed safe spacing distance is further corrected by a means 3 according to the type of the front vehicle. On the basis of the corrected safe spacing distance and the detected spacing distance to the front vehicle, the travel speed of one's own vehicle is controlled by a means 4 so as to be the desirable speed. In other words, the travel speed of one's own vehicle is changed according to the type of the front vehicle so as to enable following travel. Accordingly, a driver is to concentrate only on steering operation during auto matic following.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vehicle travel control device, and particularly to a vehicle travel control device for safely following various vehicles in front.

[Conventional technology] Conventionally, there have been travel control devices equipped with sensors such as radar devices on vehicles that constantly monitor the distance and relative speed between the vehicle and the vehicle in front, thereby ensuring a safe distance between vehicles and following the vehicle in front. It is well known.

This type of travel control device uses a radar device such as an antenna to detect the inter-vehicle distance and relative speed of the vehicle in front.
A speed sensor also detects the traveling speed of the vehicle. The detected inter-vehicle distance, relative speed, and own vehicle speed are then sent to the signal processing device.

The signal processing device calculates the safe following distance to the vehicle ahead from these detection signals sent, compares the calculated safe following distance with the current following distance, and determines the acceleration/deceleration of the own vehicle. The system sends commands to various actuators to operate the brakes and accelerator to safely follow the vehicle ahead.

Alternatively, based on information on the driving conditions of the vehicle ahead and the own vehicle from various sensors, multiple dangerous areas with a high possibility of collision with the vehicle ahead can be set in stages according to the degree of possibility, and the A device has also been considered to send control signals to the vehicle's running state and occupant protection means as needed to safely control the vehicle's running.

However, in these driving control devices, the safe distance to the vehicle in front is uniformly determined by the driving condition relative to the vehicle in front, so it cannot be adapted to the driving conditions that vary depending on the surrounding situation. There was a problem. In other words, when the vehicle ahead is a large truck, the forward visibility is insufficient compared to when the vehicle is a regular passenger car, etc., and the driver feels more dangerous and takes a longer safe following distance than when driving a regular passenger car. There is a tendency. However, the conventional control device described in item 1 does not take into account the identification of the vehicle type of the vehicle ahead, and calculates the safe inter-vehicle distance in the same way whether the vehicle ahead is a regular passenger car or a large truck.

Therefore, in the past, a travel control device such as that disclosed in Japanese Patent Laid-Open No. 61-6031 has been considered. This device is configured to calculate a safe inter-vehicle distance and control driving based on the detection results from a vehicle speed detection means for detecting the own vehicle speed and an inter-vehicle distance detection means for detecting the inter-vehicle distance from the preceding vehicle. When it is desired to change the safe inter-vehicle distance depending on surrounding conditions or driving conditions, the safe inter-vehicle distance is adjusted as appropriate by turning a manual knob of the inter-vehicle distance adjusting means.

[Problems to be Solved by the Invention] However, in the above-described travel control device, there is a problem in that a manual knob must be operated each time the safe inter-vehicle distance is desired to be changed, making the operation complicated. If the driver has to operate the manual knob each time to set the value desired by the driver, the advantage of automatic following driving, which is that the driver only needs to concentrate on steering operation while automatically following the vehicle in front, is lost. Not only will you be exposed to
It is difficult for the driver to set this manual knob to a desired value while driving, and erroneous operation is likely to occur. Furthermore, since the driver's attention is directed to the operation at hand, there is a problem in that the driver cannot concentrate on driving and lacks consideration for safety.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to automatically set a safe distance between vehicles according to the surrounding conditions, especially the type of vehicle in front, so that the vehicle can follow the vehicle in front more safely. The object of the present invention is to provide a vehicle travel control device that can perform the following functions.

[Means for Solving the Problems] In order to achieve the above object, as shown in FIG. A safe inter-vehicle distance between the vehicle in front and the vehicle is calculated based on the relative speed of the vehicle in front and the speed of the vehicle detected by the vehicle and the vehicle in front of the vehicle. a safe following distance calculating means 2; a safe following distance correcting means 3 for correcting the safe following distance calculated by the safe following distance calculating means according to the type of vehicle in front detected by the driving condition detecting means; The driving control means 4 controls the speed of the own vehicle to a desired speed based on the safe inter-vehicle distance corrected by the safe inter-vehicle distance correction means and the inter-vehicle distance to the preceding vehicle detected by the driving situation detection means. The feature is that the vehicle follows the vehicle by changing its speed depending on the type of vehicle ahead.

[Function] The vehicle running control device of the present invention has the above-described configuration, and the running condition detection means detects the inter-vehicle distance with the preceding vehicle, the relative speed, and the speed of the own vehicle, and also detects the vehicle type of the preceding vehicle. To detect. Then, the safe following distance between the preceding vehicle and the own vehicle is calculated from the relative speed of the preceding vehicle and the speed of the own vehicle detected by the driving situation detection means, and the safe following distance correction means uses the calculated safe following distance. is corrected as appropriate depending on the type of vehicle ahead.

In other words, if the vehicle ahead is a large truck, etc.
The safe inter-vehicle distance is corrected to be larger than that of an ordinary passenger car, etc., and the safe inter-vehicle distance is corrected to match the degree of danger that a driver would feel during actual driving.

In this way, by using the vehicle type of the vehicle ahead as a parameter for calculating the safe following distance, it is possible to automatically adjust the safe following distance according to the vehicle type of the vehicle ahead, and the corrected safe following distance can be calculated. By controlling the speed of the host vehicle based on the following, the travel control means can perform follow-up travel while ensuring a safe inter-vehicle distance depending on the vehicle type of the vehicle in front.

[Embodiments] Hereinafter, preferred embodiments of the vehicle travel control device according to the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram showing the overall configuration of this embodiment,
Visual sensor 10. System operation switch 12, vehicle speed setting switch 14. Own vehicle speed sensor 16 and acceleration sensor 18
The driving condition detecting means is constructed from the following. Here, the visual sensor 10 uses a scanning laser radar device,
A narrowly focused laser beam is scanned on a horizontal plane at constant angles θ to measure the inter-vehicle distance to the vehicle ahead and the size of the vehicle ahead. That is, the inter-vehicle distance R to the preceding vehicle can be calculated from the time difference between when the laser beam irradiated in front of the own vehicle irradiates the preceding vehicle and when it returns, and the scan angle θ is θ. ~θ. Assuming that a vehicle ahead is detected between
The size of the vehicle ahead at the inter-vehicle distance R can be determined from n.

The visual sensor 10 is configured to use an image sensor such as a camera in addition to the scanning laser radar device used in this embodiment, and to perform image processing to determine the distance and size of the vehicle ahead. You may do so.

Additionally, a system activation switch 12 and a set vehicle speed switch 14 are provided near the steering wheel of the own vehicle, and by manually operating these switches, the driver can turn on/off the operation of the cruise control device and set the maximum speed during follow-up driving. Can be set.

The own vehicle speed sensor 16 is a sensor that detects the vehicle speed by detecting the number of pulses generated by the rotation of a magnet plate that rotates according to the vehicle speed.

For example, a piezoelectric acceleration sensor can be used as the acceleration sensor 18, and acceleration can be detected using a potential difference caused by mechanical distortion of a ceramic piezoelectric element that occurs in response to acceleration. Detection signals from these various sensors are input to an arithmetic processing unit (ECU) that performs various arithmetic processing.

The calculation processing unit ff (ECU) 20 has an input port 20a into which detection signals from the various sensors described above are input.

It is equipped with a ROM 20b, a RAM 20c, a CPU 20d, and an output port 20e, and the CPU 20d is the input port 2.
Based on detection signals from various sensors inputted to 0a, a safe inter-vehicle distance and correction of this safe inter-vehicle distance are performed and outputted to an output port 20e.

A throttle actuator 22. which controls the throttle opening from the output port 20e. It is configured to send a control signal to a brake actuator 24 that controls the brakes and an alarm generating device 26 that issues a visual or auditory warning to the driver.

The operation of this embodiment will be explained below using the control flowchart shown in FIG. First, in step 30, it is determined whether the system activation switch 12 is activated. If YES in this step, that is, the system is turned on, a predetermined vehicle speed Vo set by the driver using the set vehicle speed switch 14 is input in step 32. Next, in step 34, the own vehicle speed V detected by the own vehicle speed sensor 16 is input, and in step 36, the inter-vehicle distance R to the preceding vehicle detected by the visual sensor 10, that is, the scanning laser radar device, and the preceding vehicle are detected. The scan angle θ is input.

The CPU 20d, to which various detection signals are input in steps 30 to 36, performs the following arithmetic processing based on these detection signals. That is, first, from the inter-vehicle distance R to the vehicle ahead detected by the visual sensor 1G and the scan angle θ, the above-mentioned formula (1) R(θ −θ )−R−mθ (1
) n+m n The size of the vehicle ahead is calculated. It is determined that the size of the vehicle ahead calculated in this way is larger than a predetermined value, that is, it is not a structure on the road such as a guardrail, and step 38
If YES is determined in the determination step, the relative speed V 1 to the vehicle ahead is calculated in the next step 40. The relative speed VR can be obtained by time-differentiating the inter-vehicle distance R detected by the visual sensor 0 to the vehicle ahead. Then, in the next step 42, a safe inter-vehicle distance R8 is calculated from this relative speed VR and the own vehicle speed V detected by the own vehicle speed sensor 6.

Generally, the safe inter-vehicle distance R8 is determined by the own vehicle speed V and the relative speed VR.
Also, as a function of the own vehicle's acceleration α and the acceleration of the vehicle ahead β, R-f 1 (V, VR, a, β) □...(2)
Specifically, for example, R-V-t
+V2/2α-(V+V)2S
R/2β...(
3) can be expressed as follows. However, t is the idle running time, and β can be determined by the time differentiation of the forward vehicle speed V+vR.

Note that the safe inter-vehicle distance R8 thus calculated according to equation (3) is the safe inter-vehicle distance within the throttle control range. In other words, this is a safe inter-vehicle distance at which a collision with the vehicle in front can be prevented by only operating the throttle without operating the brakes. On the other hand, if the distance between the vehicles suddenly decreases due to an interruption by another vehicle from another lane while following the vehicle in front, such throttle operation alone will not be enough, and brake control will also be required. .

The next step 44 is to calculate the dangerous inter-vehicle distance R9, which requires not only a throttle operation but also a brake operation. Using the maximum acceleration α'' when the throttle is fully closed and the engine brake is applied, it can be expressed as R-f (v, vR1 α゛, β) (4) 2.

1 By the way, the safe inter-vehicle distance R calculated in step 42
is primarily determined from the own vehicle speed V and the relative speed VR with respect to the vehicle in front, but most drivers are concerned about their forward visibility when the vehicle in front is a large vehicle such as a bus or truck. Compared to regular passenger cars, drivers feel a greater sense of danger due to the fact that they do not have sufficient distance between vehicles compared to regular passenger cars, and therefore tend to maintain a longer distance between vehicles compared to regular passenger cars. Therefore, in order to more closely match the actual driving sensation, it is necessary to correct the safe inter-vehicle distance R8 calculated based on the vehicle type of the vehicle ahead to reduce the driver's sense of danger.

The following steps are provided to perform such correction. First, in step 46, the type of vehicle in front is identified. In other words, if R-mθ of the vehicle ahead, which is determined by equation (1) from the distance R to the vehicle ahead, which is the detection signal from visual sensor 0, and the scan angle θ, is less than 1.7 m, then the size of the passenger vehicle and the vehicle ahead is determined. If the length is 1.7m to 1.9m, it is a regular passenger car or small truck, 1.9m to 2.2m.
If the distance is 2.2 m to 2.5 m, then 2. Decide in advance the type of vehicle in front that corresponds to the size of the vehicle in front, such as a large bus or trailer, and use the arithmetic processing circuit (E
CU) 20. Then, the size Ramθ of the detected vehicle ahead is compared with the content stored in the memory, and the type of vehicle currently detected is identified. Then, in the next step 48, based on the identified vehicle type of the vehicle ahead, the safe inter-vehicle distance R8 is corrected according to the vehicle type.

As a correction method, for example, as shown in Fig. 5, a correction amount is determined in advance according to each vehicle type, and if the vehicle ahead is a truck, the correction amount C for the truck is set to the safe inter-vehicle distance R8. It can be corrected as follows: R8°-C3·R8-(5).

In this way, in this embodiment, the safe inter-vehicle distance is corrected according to the type of vehicle in front that should be followed.In other words, when the preceding vehicle is a large vehicle such as a bus or truck, the safe inter-vehicle distance is By correcting to increase the value, the driver can reduce the feeling of pressure that the driver may feel during actual driving due to the type of vehicle, and enable comfortable follow-up driving.

Now, the safe inter-vehicle distance R8' corrected according to the vehicle type in step 48 is compared in magnitude with the current inter-vehicle distance MR to the vehicle in front in the next step 50, and if YES, the current inter-vehicle distance R is calculated. If it is determined that the safe inter-vehicle distance R8' is greater than the safe inter-vehicle distance R8', the process moves to step 52, where the host vehicle speed V and the set vehicle speed V set by the driver are set. The size relationship between the two is compared. If it is determined in step 52 that the current vehicle speed V is smaller than the set vehicle speed Vo, that is, YES, this means that the current inter-vehicle distance is longer than the safe inter-vehicle distance and smaller than the set vehicle speed. So,
In the next step 54, a control signal is sent to the throttle actuator to increase the opening degree of the throttle and control the vehicle speed V to increase.

On the other hand, if the result in step 50 is NO, that is, the inter-vehicle distance R is determined to be shorter than the safe inter-vehicle distance R8'', this means that there is a possibility of a collision with the vehicle ahead, so in the next step 56 the throttle actuator is The controller sends a control signal to the controller to reduce the opening degree of the throttle to reduce the host vehicle speed V.The same control is also performed when the host vehicle speed is larger than the set vehicle speed 0 at step 52. be exposed.

Then, the process moves to step 58, where the inter-vehicle distance MR is compared with the dangerous inter-vehicle distance R9 calculated at step 44, and NO is determined.
9, that is, when it is determined that the inter-vehicle distance R is shorter than the dangerous inter-vehicle distance RD, this means that the current inter-vehicle distance is shorter than the inter-vehicle distance that requires brake operation, so in the next step 60, the alarm generation device is activated. A control signal is sent to 26 to issue a visual or auditory warning to the driver.

Then, it is determined in the next step 62 whether or not the driver has responded to the generated warning, and if the driver has not responded to this warning, that is, the determination is NO in this step, the next step 62 is determined. The process moves to step 64, where a control signal is sent to the brake actuator, and control is performed to reduce the speed of the own vehicle.

In this way, the present invention corrects the safe inter-vehicle distance according to the vehicle type of the vehicle ahead, thereby taking into account the vehicle types of the six vehicles ahead as parameters, in addition to the distance between the vehicle and the vehicle ahead, the relative speed, and the own vehicle speed. By doing so, the degree of danger and pressure that an actual driver would feel is reflected in the safe following distance, making it possible to follow the vehicle in front more safely and comfortably.

[Effects of the Invention] As explained above, according to the vehicle travel control device according to the present invention, the safe inter-vehicle distance is automatically adjusted depending on the vehicle type of the vehicle ahead, so This has the effect of making it possible to follow various vehicles ahead.

Further, according to the present invention, since the driver does not have to worry about manual operation, he only has to concentrate on steering operation while automatically following the vehicle in front, which has the effect of enabling safer driving.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the configuration of the present invention; FIG. 2 is a block diagram of the overall configuration of an embodiment of a vehicle travel control device according to the present invention; FIG. 3 is a control flowchart of the embodiment; FIG. 4 is an explanatory diagram for identifying the type of vehicle ahead according to the same embodiment, and FIG. 5 is a table diagram for calculating the safe inter-vehicle distance correction amount according to the same embodiment. 10... Visual sensor 12... System operation switch 14... Vehicle speed setting switch 16... Own vehicle speed sensor 18... Acceleration sensor 20... Arithmetic processing unit (ECU) 22...
Throttle actuator 24 ... Brake actuator 26 ... Alarm generating device

Claims (1)

[Scope of Claims] A driving condition detecting means including sensors for detecting the inter-vehicle distance, relative speed, and vehicle type as well as the speed of the own vehicle, and the relative speed of the preceding vehicle detected by the driving condition detecting means. and a safe following distance calculating means for calculating a safe following distance between the vehicle in front and the own vehicle based on the speed of the own vehicle; and a safe following distance calculated by the safe following distance calculating means being detected by the driving condition detecting means. a safe following distance correction means that corrects the following vehicle according to the vehicle type of the preceding vehicle; and a safe following distance corrected by the safe following distance correcting means and the following distance to the preceding vehicle detected by the driving condition detecting means. What is claimed is: 1. A vehicle travel control device comprising: a travel control means for controlling the speed of the own vehicle to a desired speed; the vehicle travel control device changes the travel speed of the own vehicle according to the type of vehicle of the vehicle ahead to follow the vehicle.