JPH04219430A - Traveling controller for vehicle - Google Patents

Abstract

PURPOSE:To improve safety in the control for the distance between his vehicle and the vehicle in front by setting an aimed compensating vehicle-to-vehicle distance larger than an aimed vehicle-to-vehicle distance which is set based on his own vehicle speed when it is necessary to ensure the longer distance to the vehicle in front than usual at the time of raining or the like. CONSTITUTION:A vehicle speed signal from a speed detector 2 is inputted into an aimed vehicle-to-vehicle distance setting part 8, and a received signal from a vehicle-to- vehicle distance detector 4 which detects the actual distance between his own vehicle and a vehicle in front is inputted into a signal level judging part 6. The judging part 6 compares the level of a received signal inputted from the vehicle-to-vehicle detector 4 with the set signal level, and if the received signal level is less than the set signal level at the time of raining or the like, the judging part outputs a judgment signal to the aimed vehicle-to-vehicle distance setting part 8. Besides, if the judgment signal is inputted into the aimed vehicle-to-vehicle distance setting part 8, an aimed compensating vehicle-to-vehicle distance which is larger than the usual aimed vehicle-to-vehicle distance is set. An ASC processing part 10 performs computation to control the vehicle- to-vehicle distance according to judged results in the signal level judging part 6.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a vehicle running control device that controls the following distance so that the actual distance to the vehicle in front follows the target distance, and particularly in conditions where the braking distance becomes long such as during rain. The present invention relates to a vehicle travel control device suitable for correcting a target inter-vehicle distance to a longer value to improve safety.

0002

[Prior Art] Conventionally, as a device of this kind, there is a
There is one proposed in the 6031 publication. As shown in Fig. 4, the proposal includes a radar device 31 that measures the distance between the vehicle in front of the vehicle, a vehicle speed sensor 32 that detects the vehicle speed of the own vehicle, and a reference distance between the vehicle and the vehicle in front that is manually operated. A manual adjustment means 33 for making adjustments, and a microcomputer 3 that performs arithmetic processing based on the information.
4, and an acceleration/deceleration mechanism 35 that operates the throttle opening, mission device, etc. according to commands from the microcomputer 34. The microcomputer 34 is
The reference inter-vehicle distance to the preceding vehicle is calculated based on the vehicle speed signal input from the vehicle speed sensor 32, and the set inter-vehicle distance is further adjusted in response to an instruction to increase or decrease the reference inter-vehicle distance that the driver performs via the manual adjustment means 33. calculate. Then, a comparison calculation is made between the distance measured by the radar device 31 to the vehicle in front and the set distance between vehicles, and based on the result, acceleration/deceleration commands are increased so that the actual distance to the vehicle in front converges to the set distance. is applied to the speed reduction mechanism 35. The acceleration/deceleration mechanism 35 controls the vehicle speed by operating the throttle opening, the transmission device, etc. according to commands from the microcomputer 34 .

[0003] In this way, the vehicle speed is controlled so as to follow the set inter-vehicle distance, which is the standard inter-vehicle distance determined from the vehicle speed of the own vehicle, which is corrected by the driver based on weather conditions, road surface conditions, and the like.

0004

[Problems to be Solved by the Invention] However, with the above-mentioned proposed device, when a driver wants to maintain a long distance from the vehicle in front, such as during rainy weather, the driver must manually operate the standard. Since the distance between vehicles must be corrected, there is a problem in that the operation becomes complicated.

[0005] The present invention has been made in view of the above problems, and its purpose is to provide a vehicle with a distance between the vehicle and the vehicle in front that is required to be longer than usual, such as during rainy days.
A vehicle driving system in which a corrected target inter-vehicle distance is set that is larger than the target inter-vehicle distance set based on the own vehicle speed, and safety can be improved by controlling the inter-vehicle distance to follow this corrected target inter-vehicle distance. The purpose is to provide a control device.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a radar type inter-vehicle distance detection means for detecting the actual inter-vehicle distance between the preceding vehicle and the own vehicle, and a target inter-vehicle distance detecting means for setting a target inter-vehicle distance. A vehicle travel control device comprising: a distance setting means; and a control means for performing inter-vehicle distance control such that the actual inter-vehicle distance inputted from the inter-vehicle distance detection means follows the target inter-vehicle distance set by the target inter-vehicle distance setting means. further comprising a received signal determining means for determining that the magnitude of the received signal level inputted from the inter-vehicle distance detecting means is equal to or lower than a preset signal level and outputting the determined signal; The present invention is characterized in that the inter-vehicle distance setting means sets a corrected target inter-vehicle distance larger than the target inter-vehicle distance when a determination signal is input from the received signal determination means.

[0007]

[Operation] According to the present invention having the above configuration, a predetermined signal level corresponding to the actual inter-vehicle distance to the vehicle in front is set in advance as a set signal level, and the reception signal is received by the radar-type inter-vehicle distance detection means due to rain or the like. When the signal is attenuated and the received signal determining means determines that the magnitude of the received signal level is less than or equal to the set signal level, a determination signal is output. In response to the determination signal, the target inter-vehicle distance setting means sets a corrected target inter-vehicle distance larger than the normal target inter-vehicle distance corresponding to the host vehicle speed, and the control means controls the inter-vehicle distance so as to follow this corrected target inter-vehicle distance. Therefore, under conditions where the braking distance is long, such as during rain, a sufficient distance between the vehicle and the vehicle in front can be ensured, and safety can be improved.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of a vehicle travel control device according to the present invention. The traveling direction of the vehicle 20 shown in FIG. 1 is the left-hand direction in the figure.

The vehicle 20 includes a speed detector 2, an inter-vehicle distance detector 4 as a radar-type inter-vehicle distance detection means, a signal level determination unit 6 as a received signal determination means built into the on-vehicle computer, and a target inter-vehicle distance detector. A target inter-vehicle distance setting section 8 as a setting means, and a constant speed driving control (auto speed control, hereinafter abbreviated as ASC) processing section 10 as a control means are provided.

[0010] As the speed detector 2, a speed sensor commonly used in a speedometer or the like is employed. The vehicle speed signal generated by the speed detector 2 is sent to the target inter-vehicle distance setting section 8.
is input.

The inter-vehicle distance detector 4 is provided near the front end of the vehicle 20 and detects the actual inter-vehicle distance between the own vehicle and the vehicle ahead. As this inter-vehicle distance detector 4, a radio wave radar device such as a microwave radar is employed. The reception signal received by the inter-vehicle distance detector 4 is input to the signal level determination section 6.

[0012] In the signal level determination section 6, the level of the received signal inputted from the inter-vehicle distance detector 4 is compared with a preset signal level, and if the magnitude of the received signal level is below the set signal level, For example, a judgment signal is output. This determination signal is input to the target inter-vehicle distance setting section 8.

In the target inter-vehicle distance setting section 8, when the determination signal is input from the signal level determination section 6, a corrected target inter-vehicle distance that is larger than the normal target inter-vehicle distance is set. The normal target inter-vehicle distance or the corrected target inter-vehicle distance is input to the ASC processing section 10.

The ASC processing unit 10 controls the inter-vehicle distance so that the actual inter-vehicle distance with the vehicle in front follows the normal target inter-vehicle distance or the corrected target inter-vehicle distance according to the determination result of the signal level determination unit 6. calculation processing is performed.

The signal level determination unit 6, target inter-vehicle distance setting unit 8, and ASC processing unit 10 described above are constituted by an on-vehicle computer as hardware, and include an input interface unit that takes in vehicle speed signals, etc., and a comparison calculation unit. It is composed of a CPU section that executes processing, a memory section that stores calculation programs, a target inter-vehicle distance map, etc., and an output interface section that outputs throttle opening control signals and the like.

Next, the operation of this embodiment having the above configuration will be explained. FIG. 2 is a flowchart showing a case where the functions of the vehicle cruise control device according to the present invention are incorporated into the main routine of the ASC of the vehicle.

As shown in FIG. 2, when the main routine is started at S1, the speed detector 2 is first detected at the signal input section S2.
The vehicle speed signal input from the vehicle is captured.

The main determination section S3 determines the state of the main switch that activates the control by the ASC. If the main switch is in the OFF state, main OFF processing S20 and normal running processing S21 are executed, and the mode shifts to a normal manual speed control mode that does not rely on ASC. If the main switch is in the ON state, control by the ASC is started.

The set determination section S4 determines the state of the set switch. The set switch is for setting the speed of constant speed driving control by ASC. If the set switch is in the OFF state, normal running processing S21 is executed and the mode shifts to manual speed control mode. When the set switch is turned on when the vehicle reaches the speed desired by the driver, constant speed driving control by the ASC is thereafter started at the speed at which the set switch was turned on. Also,
If the set switch is kept in the ON state, the control mode shifts to the set acceleration process S5, and the speed is set at the speed when the driver turns off the set switch after reaching the speed desired by the driver. Speed running control is started.

[0020] In the coast determining section S6, the state of the coast switch is determined. The coast switch is a switch that allows the driver to decelerate the vehicle without operating the brake pedal. When the coast switch is kept in the ON state, the process moves to coast processing S30, during which the vehicle continues to decelerate and the driver From now on, constant speed driving control by ASC is performed at the speed when the coast switch is turned OFF. If the coast switch is in the OFF state, the process moves to the resume determination section S7.

[0021] The resume determining section S7 determines the state of the resume switch. The resume switch is used to decelerate by operating the coast switch mentioned above, or once the ASC control is released by operating the brake pedal, to return to the original speed again and perform constant speed driving control by ASC. There is a return switch for the case. When the resume switch is turned on, resume processing S4
0 is executed, the vehicle returns to its original speed, and from then on A
Shifts to constant speed driving control using SC. If the resume switch is in the OFF state, the process moves to inter-vehicle distance measurement S8.

In the inter-vehicle distance measurement S8, the inter-vehicle distance detector 4
The actual distance between the vehicle and the vehicle ahead is measured. Here, the operation of the inter-vehicle distance detector 4 will be explained with reference to FIG. 3. FIG. 3 is a waveform diagram of the transmitted and received waves of the inter-vehicle distance detector 4. The graph in FIG. 3 is drawn with the modulation frequency f on the vertical axis and the time T on the horizontal axis. The received wave reflected by the vehicle ahead and received by the inter-vehicle distance detector 4 is delayed by the transmission/reception delay time Td with respect to the transmitted wave. In order to determine the actual inter-vehicle distance to the vehicle ahead, it is sufficient to know this transmission/reception delay time Td. On the other hand, the modulation frequency f changes periodically as shown in FIG. 3, and the frequency difference fb between the modulation frequency of the transmitted wave and the modulation frequency of the received wave is uniquely determined with respect to the transmission/reception delay time Td. Therefore, if you measure the frequency of the beat signal generated by interference between the transmitted wave and the received wave,
The actual distance between the vehicle and the vehicle in front is determined.

Subsequently, received signal level determination S9 is executed. In reception signal level determination S9, inter-vehicle distance measurement S
The level of the beat signal explained in 8 is compared with the set signal level. The level of the beat signal takes a value corresponding to the actual distance between the vehicle in front and the vehicle in front when there are no obstacles between the own vehicle and the vehicle in front, such as on a clear day, so this value should be used as the set signal level. Set it. If the beat signal level exceeds the set signal level, the normal target inter-vehicle distance setting S
10. If the beat signal level is below the set signal level, correction target inter-vehicle distance setting S10a is executed.

In the normal target inter-vehicle distance setting S10, the normal target inter-vehicle distance previously set and stored in the target inter-vehicle distance setting section 8 is read out in accordance with the own vehicle speed detected by the speed detector 2. Normally, the set value of the target inter-vehicle distance is set to a value that is approximately proportional to the vehicle speed, and is stored in a memory unit such as a ROM.

In the corrected target inter-vehicle distance setting S10a, a correction target inter-vehicle distance is set and stored in advance in a memory area different from the normal target inter-vehicle distance of the target inter-vehicle distance setting section 8, corresponding to the own vehicle speed detected by the speed detector 2. The corrected target inter-vehicle distance is read out. The corrected target inter-vehicle distance is set to a value larger than the normal target inter-vehicle distance, taking into account that the braking distance increases during rain or the like. Note that the corrected target inter-vehicle distance may be calculated by multiplying the corresponding normal target inter-vehicle distance by a predetermined coefficient.

Subsequently, ASC processing S11 is executed. In the ASC process S11, a throttle opening control command value is used to control the following distance so that the normal target following distance or the corrected target following distance follows the actual inter-vehicle distance to the preceding vehicle measured in the following distance measurement S9. calculations, etc. are performed.

Finally, an output process S12 is executed to output the calculation result to an actuator, an indicator, etc. that controls the throttle opening, and the main routine ends in S13.

As described in detail above, in this embodiment, a predetermined beat signal level corresponding to the actual inter-vehicle distance to the preceding vehicle is set as the set signal level, and the actual beat signal level detected by the inter-vehicle distance detector 4 is The signal level and the aforementioned set signal level are compared in the signal level determination section 6. Then, if the actual beat signal level is below the set signal level,
A corrected target inter-vehicle distance that is larger than the normal target inter-vehicle distance that is approximately proportional to the own vehicle speed is set, and the inter-vehicle distance is controlled by the ASC processing unit 10 so that the actual inter-vehicle distance with the vehicle in front follows this corrected target inter-vehicle distance. Even under conditions where the braking distance is long, such as during rain, a sufficient inter-vehicle distance can be ensured and safety can be improved.

[0029]

[Effects of the Invention] As detailed above, according to the present invention,
The received signal level received by the radar type inter-vehicle distance detection means and a preset signal level set in advance corresponding to the actual inter-vehicle distance to the preceding vehicle are compared by the received signal determination means. If the magnitude of the received signal level is equal to or less than the set signal level, the determination signal is input to the target inter-vehicle distance setting means, and the target inter-vehicle distance setting means determines that the received signal level is larger than the normal target inter-vehicle distance that is approximately proportional to the own vehicle speed. A corrected target inter-vehicle distance is set, and the inter-vehicle distance is controlled by the control means so that the corrected target inter-vehicle distance follows the actual inter-vehicle distance to the vehicle in front, so the braking distance can be adjusted even under conditions where the braking distance becomes long, such as during rain. This also ensures a sufficient distance between vehicles and improves safety.

[Brief explanation of the drawing]

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

FIG. 2 is a flowchart showing an embodiment in which the functions of the vehicle cruise control device according to the present invention are incorporated into the main routine of constant speed cruise control.

FIG. 3 is a waveform diagram of transmitted and received waves of the inter-vehicle distance detector 4. FIG.

FIG. 4 is a block diagram showing the configuration of a conventional technique.

[Explanation of symbols]

2 Speed detector 4 Inter-vehicle distance detector 6 Signal level determination section 8 Target inter-vehicle distance setting section 10 ASC processing section 20 Vehicle fb Modulation frequency frequency difference Td Transmission/reception delay time

Claims (1)

[Claims] 1. Radar-type inter-vehicle distance detection means for detecting the actual inter-vehicle distance between the preceding vehicle and the host vehicle, target inter-vehicle distance setting means for setting a target inter-vehicle distance, and actual inter-vehicle distance input from the inter-vehicle distance detection means. In the vehicle travel control device, the vehicle travel control device includes a control means for performing inter-vehicle distance control to make the distance follow the target inter-vehicle distance set by the target inter-vehicle distance setting means, the magnitude of the received signal level input from the inter-vehicle distance detection means. The target inter-vehicle distance setting means receives the determination signal from the received signal determination means, and the target inter-vehicle distance setting means receives the determination signal from the received signal determination means. A vehicular travel control device characterized in that when the target inter-vehicle distance is determined, a corrected target inter-vehicle distance is set larger than the target inter-vehicle distance.