JP2503681B2 - Vehicle drive controller - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle traveling control device, and more particularly to a vehicle traveling control device suitable for automatically controlling a traveling state of a vehicle to automatically follow a vehicle ahead.

[Prior Art] Recently, mainly for protecting passengers and facilitating driving operation,
A travel control device has been developed in which a radar device is mounted on an automobile to constantly monitor a vehicle-to-vehicle distance and a relative speed with respect to a vehicle in front and to accelerate and decelerate the vehicle according to a degree of danger.

An example of this type of travel control device is Japanese Patent Laid-Open No. 60-915.
The system disclosed in Japanese Patent Publication No. 00 is known. FIG. 9 shows a schematic block diagram of this system. In the figure,
A radar device 10 having an antenna ANT detects a vehicle-to-vehicle distance and a relative speed with respect to a vehicle ahead and a speed sensor.
The traveling speed of the own vehicle is calculated by 12.

Then, the detected inter-vehicle distance, relative speed, and own vehicle speed are sent to the signal processing device 14. The signal processing device 14 calculates the risk index from these sent detection signals. That is, when the front vehicle decelerates and then stops, the appropriate inter-vehicle distance necessary for the own vehicle to stop without collision is obtained from the traveling state of the front vehicle and the traveling state of the own vehicle. = Log (appropriate inter-vehicle distance / actual inter-vehicle distance) The risk index D is calculated according to the equation.

This risk index calculated by the signal processing device 14 is sent to the display device 16 for audiovisual display, and the driver operates the brake and the accelerator according to this display while securing an appropriate inter-vehicle distance with the vehicle in front. You can follow the vehicle ahead. Alternatively, the signal processing device 14 can determine the acceleration / deceleration of the own vehicle based on the risk index and issue a command to the actuator to automatically control the brake and the accelerator to safely follow the preceding vehicle.

[Problems to be Solved by the Invention] However, there are some problems in the conventional system. As described above, the conventional system uses the inter-vehicle distance to the preceding vehicle, the relative speed, and the own vehicle speed as parameters for evaluating the risk level. Therefore, as long as the inter-vehicle distance to the preceding vehicle, the relative speed, and the own vehicle speed are the same, this system evaluates the risk as the same. However, in actual vehicle operation, the distance between the vehicle ahead and the
Even if the relative speed and the own vehicle speed are the same, when the front vehicle and the own vehicle are traveling in the same direction, or when the relative position between the own vehicle and the preceding vehicle is distant, and the own vehicle is in the same direction as this relative position. When the vehicle is not steered, that is, when the host vehicle is not heading toward the vehicle in front, the risk is significantly different, and in the latter case, the driver does not feel as dangerous as in the former case.

Thus, in the conventional system, for example, even when the vehicle in front is traveling in another lane and is relatively distant from the traveling direction of the own vehicle, the risk level to the driver is the same as in the same traveling direction. This is displayed or braked, so that it does not match the actual operation feeling, and gives the driver considerable discomfort.

The present invention has been made in view of the above conventional problems,
It is an object of the present invention to provide a vehicle traveling control device capable of evaluating a degree of danger in accordance with a driver's actual operation feeling and performing more optimal following traveling.

[Means for Solving the Problems] In order to achieve the above-mentioned object, a vehicle travel control device of the present invention provides a vehicle-to-vehicle distance, a relative speed, and a vehicle speed with respect to a vehicle ahead, as well as a relative position and a vehicle ahead. The feature is that the degree of danger is evaluated using the steering angle of the vehicle as a parameter. That is, the present invention is a scanning laser radar device that detects a vehicle-to-vehicle distance, a relative speed, and a relative position indicating a deviation in a traveling direction between a front vehicle and a vehicle, and a vehicle speed that detects a traveling speed of the vehicle. A sensor, a steering angle sensor that detects the steering angle of the own vehicle, and based on detection signals from the laser radar device, the vehicle speed sensor, and the steering angle sensor, and based on the relative position and the steering angle, the own vehicle is ahead of the vehicle. If it is heading, the risk level calculation means for calculating the risk level index so that the value increases, and the appropriate inter-vehicle distance between the preceding vehicle and the host vehicle based on the risk level index calculated by this risk level calculation means. An appropriate inter-vehicle distance calculating means for calculating and an appropriate vehicle speed operation amount control means for calculating the acceleration / deceleration control amount of the own vehicle based on the appropriate inter-vehicle distance calculated by the appropriate inter-vehicle distance are provided, and the relative position with respect to the preceding vehicle and Check the steering angle of your vehicle To the own vehicle it is characterized by controlling the travel of the host vehicle and estimating the risk by considering whether towards the front wheel.

[Operation] Not only the inter-vehicle distance to the preceding vehicle, the relative speed, and the own vehicle speed are used as parameters for evaluating the risk,
By evaluating the relative position indicating the deviation in the traveling direction with the preceding vehicle as well as the steering angle of the own vehicle, it is possible to perform the risk evaluation closer to the actual driving feeling. That is,
Even if the following distance, relative speed, and own vehicle speed are the same as the preceding vehicle, the relative position between the preceding vehicle and the own vehicle is not zero, and the steering angle of the own vehicle is not in the same direction as this relative position. When the direction is moving away from the vehicle in front, the risk is evaluated to be smaller, so that it can be more adapted to the risk that the actual driver may feel.

Then, an appropriate inter-vehicle distance is calculated based on this degree of danger, and the own vehicle speed is controlled in order to maintain the own vehicle at this appropriate inter-vehicle distance, so that optimum automatic tracking becomes possible.

[Embodiment] A preferred embodiment of a vehicle travel control device according to the present invention will be described below with reference to the drawings. FIG. 1 is a configuration block diagram of the present embodiment. In the figure, a scanning laser radar device 20 mounted on a vehicle scans the front of the vehicle while irradiating laser light at a predetermined pulse interval. The scanned laser light is reflected by the front vehicle traveling in front of the own vehicle, and by receiving the reflected laser light, the inter-vehicle distance to the front vehicle, the relative speed, and the deviation in the traveling direction of the front vehicle and the own vehicle are detected. The relative position represented is detected.

On the other hand, the traveling speed of the host vehicle is detected by the vehicle speed sensor 22, and the steering angle of the host vehicle is detected by the steering angle sensor 24 using a potentiometer or the like.

Then, these laser radar device 20, vehicle speed sensor 22,
The inter-vehicle distance, the relative speed, the relative position, the own vehicle speed, and the steering angle detected by the steering angle sensor 24 are sent to the risk degree calculating means 26. The risk degree calculating means 26 performs fuzzy inference using each sent detection signal as a parameter, and calculates the risk degree that matches the driver's sensation using an index. The fuzzy inference performed by the risk calculating means 26 will be described below in detail with reference to FIGS. 3 to 5.

FIG. 3 shows an evaluation standard for evaluating each parameter sent from the laser radar device 20, the vehicle speed sensor 22 and the steering angle sensor 24. As shown in the figure,
Three evaluation criteria S (Small: small), M
(Middle: middle), B (Big: large) are assigned, and relative position and steering angle are assigned evaluation criteria L (Left: left), Z (Zero: zero), R (Right: right). In addition, the relative speed is N (Negative: negative), Z (Zero: zero), P (Positi
ve: Positive) is assigned. Furthermore, there are four evaluation criteria for the output risk to be calculated: VS (VerySmall: extremely small), S (Small: small), M (Middle: medium), B (B
ig: Large) is assigned.

FIG. 4 shows the fuzzy control law expressed by the evaluation standard assigned to each parameter in this way. This fuzzy control rule adopts a rule that matches the driver's feeling. For example, in the first step in the figure, "If the vehicle speed is B (large), the relative speed is N (negative) and the inter-vehicle distance is S ( Small) and relative position Z (zero) and steering angle Z (zero)
If the vehicle speed is B (large), the relative speed is N (negative), and the inter-vehicle distance is S (small), the third stage in the figure indicates that the risk is B (large). ) And the relative position is L (left) and the steering angle is R (right), the risk is S (small) ”.

In this way, even if the vehicle speed, the relative speed, and the inter-vehicle distance are the same, by evaluating the risk degree according to the actual position by the relative position and the steering angle, it becomes possible to perform a more optimal risk degree evaluation as described later. is there.

FIG. 5 shows the membership function of the evaluation standard assigned to each parameter, and FIG. 5 (A) shows the membership of the vehicle speed of S (small), M (medium), and B (large). Figure 5 (B) shows the relative velocity N (negative), Z
Membership functions of (zero) and P (positive) are shown in FIG. 5 (C), and membership functions of S (small), M (medium), and B (large) of the inter-vehicle distances are shown in FIG. 5 (D). ) Is a membership function of relative positions L (left), Z (zero), and R (right), and FIG. 5 (E) is a steering angle of L (left), Z (zero), and R (right). The membership function, and Fig. 5 (F) shows the risk levels VS (very small), S (small),
The membership functions of M (medium) and B (large) are shown respectively. As is well known, the membership function indicates the degree to which a certain physical quantity applies to human senses. For example, in the membership function of the own vehicle speed of FIG. 5 (A), when the own vehicle speed is 50 km / h, The evaluation criteria are as follows: S (small) = B (large) = 0 M (medium) = 0.75, and the vehicle speed of 50 km / h is judged to be a medium speed by the driver's sense of 0.75. Is shown.

Now, the risk calculating means 26 inputs the values of the respective parameters sent from the laser radar device 20, the vehicle speed sensor 22 and the steering angle sensor 24, and obtains the degree of the evaluation standard from these membership functions. For example, if the vehicle speed = 100Km / h, relative speed = -50Km / h, inter-vehicle distance = 25m, relative position = -2m, steering angle = 45deg, then from the membership function, the vehicle speed: S = M = 0B = 1.0 Relative speed: P = Z = 0 N = 0.5 Distance between vehicles: S = 0.2 M = 0.2 B = 0 Relative position: R = Z = 0 L = 1.0 Steering angle: L = Z = 0 R = 1.0 .

Then, the degree of satisfaction of the fuzzy control law of FIG. 4, which is a basic rule, is evaluated from this degree. That is, in the above-mentioned example, according to the rule of the third step in Fig. 4, the vehicle speed is B = 1.0, the relative speed is N = 0.5, the inter-vehicle distance is S = 0.2, and the relative position is L. Degree = 1.0 The degree of steering angle R is 1.0, and the satisfaction of the condition part of this rule is 1.0 × 0.5 × 0.2 × 1.0 × 1.0 = 0.1. And the risk level which is the conclusion part of this rule is S
The membership function of is multiplied by the satisfaction degree of this conditional part to correct the membership function according to the satisfaction degree.

Such an operation is performed for all the fuzzy control rules shown in FIG. 4, the membership functions in the conclusion section are corrected according to the degree of satisfaction, and the corrected membership functions are ORed. Then, by calculating the center of gravity of this logical sum, it is possible to calculate the degree of danger that matches the driver's sense.

The risk calculated by the risk calculating means 26 is then sent to the appropriate inter-vehicle distance calculating means 28. Appropriate inter-vehicle distance calculation means
28 is the sent risk index and laser radar device 20
Using the relative speed from the vehicle speed and the vehicle speed from the vehicle speed sensor 22, an appropriate inter-vehicle distance between the preceding vehicle and the vehicle is calculated. That is, first, the reference inter-vehicle distance Lo at which the vehicle can be stopped without colliding with the preceding vehicle is calculated from the relative speed Vr and the own vehicle speed V according to the following equation.

Lo = V × τ + (Vs ² −V ² ) / 2α Vs = V + Vr However, the free running time of the vehicle is τ and the deceleration is α.

Then, the reference inter-vehicle distance Lo is corrected by the risk index D calculated by the risk calculating means 26 to calculate an appropriate inter-vehicle distance L.

L = G1 × (1 + D) × Lo However, the inter-vehicle distance gain is G1.

Then, the calculated appropriate inter-vehicle distance L is sent to the appropriate vehicle speed operation amount control means 30. This proper vehicle speed operation amount control means 30
Then, based on the proper inter-vehicle distance sent, the correction amount for sending a command to the throttle actuator 32 and the brake actuator 34 in order to achieve the proper vehicle speed is calculated by the risk degree calculating means.
Similar to 26, it is calculated by fuzzy reasoning.

Similar to FIG. 3, FIG. 6 shows the evaluation criteria of each parameter used for fuzzy inference. The own vehicle speed and the relative speed sent to the appropriate vehicle speed operation amount control means 30 together with the appropriate inter-vehicle distance are three evaluation criteria S similar to those in FIG.
M, B and N, Z, P are assigned. The inter-vehicle distance difference represents the difference between the proper inter-vehicle distance and the actual inter-vehicle distance. For this parameter, N (Negative: shorter than the proper inter-vehicle distance), Z (Zero: proper inter-vehicle distance), P ( Posit
ive: longer than the appropriate inter-vehicle distance), and five evaluation criteria NS (NegativeSmall: small deceleration), NB (NegativeBig: large deceleration), Z (main vehicle speed maintenance), PS ( PositiveSmall: Small acceleration), PB (Posi
tiveBig: Big acceleration) is assigned.

FIG. 7 shows the fuzzy control law expressed by the evaluation standard assigned to each parameter in this way. This fuzzy control law also adopts a rule that matches the driver's feeling as in FIG. 4. For example, in the first step in the figure, "If the vehicle speed is B (large) and the inter-vehicle distance difference is N (proper If the relative speed is N (negative) and the operation correction amount is NB (large deceleration) ",
The third step in the figure is "If the vehicle speed is B (large), the inter-vehicle distance difference is P (longer than the appropriate inter-vehicle distance), and the relative speed is Z (zero), the operation correction amount is Z (main vehicle speed maintained). Represents the rule.

FIG. 8 shows the membership function of each evaluation criterion used to evaluate the satisfaction of these rules, and FIG. 8 (A) shows the membership function of S, M, B of the own vehicle speed. FIG. 8 (B) shows the membership functions of relative speeds N, Z and B, and FIG. 8 (C) shows the inter-vehicle distance difference N,
The membership functions of Z and P are shown, and FIG. 8D shows the membership functions of NB, NS, Z, PS, and PB of the operation correction amounts.

When calculating the operation correction amount, the degree of each parameter is first obtained. For example, when the inter-vehicle distance difference is −50 m, that is, when the inter-vehicle distance is 50 m shorter than the appropriate inter-vehicle distance, the vehicle speed is 100 km / h,
Considering that the relative speed is -50m, from the membership function, the vehicle speed: S = 0 M = 0.2 B = 1.0 Distance between vehicles: P = Z = 0 N = 1.0 Relative speed: N = Z = 0.5 P = 0. Then, with respect to the rule of FIG. 1 in the fuzzy control law of FIG. 7, the own vehicle speed is B = 1.0, the inter-vehicle distance difference is N = 1.0, and the relative speed is N = 0.5. The satisfaction of the conditional part is 1.0 x 1.0 x 0.5 = 0.5. Then, the membership function whose operation correction amount is NB (large deceleration), which is the conclusion part of this rule, is multiplied by the satisfaction degree of this condition part to correct the membership function according to the satisfaction degree.

Such an operation is performed for all the fuzzy control rules shown in FIG. 7, the membership function of the conclusion part is corrected according to the satisfaction of the condition part, and the logical sum of these corrected membership functions is calculated. Then, by calculating the center of gravity of this logical sum, it is possible to calculate an operation correction amount that matches the driver's sensation and issue a command to the throttle actuator 32 and the brake actuator 34.

As described above, in this embodiment, as shown in the control flowchart of FIG. 2, in addition to the inter-vehicle distance to the preceding vehicle, the relative speed, the own vehicle speed, the relative position and the steering angle indicating the deviation in the traveling direction from the preceding vehicle. By adopting the physical quantity as a parameter, the degree of danger is more closely matched to the actual driving feeling of the driver and evaluated by fuzzy reasoning (step 36), and the appropriate inter-vehicle distance is calculated based on this degree of danger (step 38), By calculating the proper vehicle speed operation correction amount based on this proper inter-vehicle distance by fuzzy inference and controlling the own vehicle speed to be the proper vehicle speed, even when the preceding vehicle is traveling in a lane different from the own vehicle, The control is not performed without being distinguished from the case where the vehicle is traveling in the same lane as in the conventional case, and the control that matches the actual driving feeling can be performed.

[Effects of the Invention] As described above, according to the vehicle travel control device of the present invention, it is possible to evaluate the degree of danger in accordance with the actual operation feeling of the driver and perform more optimal following travel. Becomes

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a vehicle travel control device according to the present invention, FIG. 2 is a flowchart of the embodiment, and FIG. 3 is a table showing the risk control parameter evaluation criteria of the embodiment. FIG. 4 is a table showing the risk fuzzy control law of the embodiment, FIG. 5 is a graph showing the membership function of the embodiment, and FIG. 6 is an operation correction amount control parameter evaluation standard of the embodiment. FIG. 7 is a table showing the operation correction amount fuzzy control law of the same embodiment, FIG. 8 is a graph showing the membership function of the same embodiment, and FIG. 9 is a block diagram of a conventional system. Is. 20 …… Laser radar device 22 …… Vehicle speed sensor 24 …… Steering angle sensor 26 …… Danger degree calculation means 28 …… Proper vehicle distance calculation means 30 …… Proper vehicle speed operation amount control means 32 …… Throttle actuator 34 …… Brake Actuator

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G05D 1/12 9108-2F G01S 17/88 A (56) Reference JP-A-60-91500 (JP , A) JP-A-61-207226 (JP, A) JP-A-1-197133 (JP, A)

Claims (1)

(57) [Claims] 1. A scanning laser radar device for detecting a vehicle-to-vehicle distance to a vehicle ahead, a relative speed, and a relative position indicating a deviation in a traveling direction between the vehicle ahead and the vehicle, and a vehicle speed for detecting a vehicle speed of the vehicle. A sensor, a steering angle sensor for detecting the steering angle of the own vehicle, based on the detection signals from the laser radar device, the vehicle speed sensor and the steering angle sensor, and from the relative position and steering angle When the vehicle is heading, the risk index calculating means calculates the risk index so that the value increases, and the appropriate inter-vehicle distance between the preceding vehicle and the own vehicle is calculated based on the risk index calculated by the risk calculating means. An appropriate inter-vehicle distance calculation means for calculating, and an appropriate vehicle speed operation amount control means for calculating the acceleration / deceleration control amount of the own vehicle based on the appropriate inter-vehicle distance calculated by the appropriate inter-vehicle distance calculation means are provided. Relative position and operation of own vehicle The vehicle control system detects a corner own vehicle and controlling the running of the evaluation was the subject vehicle the risk by considering whether towards the front wheel.