JPH0747967A - Steering auxiliary device of automobile - Google Patents

Abstract

PURPOSE:To secure the safety of car traveling by adducing an operating direction of steering to a driver after calculating the risk of an obstacle by car itself, while in the case where it is so judged that the risk has reached to the maximum, carrying out a complete automatic steering operation in rejecting any intervention of the driver. CONSTITUTION:A sensor 1 detects a distance between an obstacle and its car and a traveling speed of the car, by way of example, and then this detected result is fed to a recognizing part 2. In addition, this recognizing part 2 receives the detected result of the sensor 1 and an operating state of steering by a driver himself detected by a torque sensor 7, thereby calculating the degree of risk to a status of one's own car. Likewise, a judging part 3 determines its operation for steering assistance on the basis of the degree of risk calculated by the recognizing part 2. In succession, a control part 4 transmits a driving signal to an actuator 6 on the basis of the determination of the judging part 3, realizing the desired steering assistance. Incidentally, in the case where there is such a mode as unintervening into the steerage according to an extent of the risk, a warning part 8 is driven for the end.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering assist device for an automobile, which judges the degree of danger and positively presents the direction in which a driver should operate the steering wheel.

[0002]

2. Description of the Related Art Conventionally, in the case of a so-called self-sustaining vehicle that travels a moving body such as an automobile or a private transportation vehicle along a predetermined lane, even if a driver is on the moving body, Steer regardless of the driver's will. In other words, in the case of this type of mobile body, when it takes the form of completely self-sustaining traveling, the driver's intention and reaction cannot be incorporated in steering change and lane change.

Further, conventionally, various proposals have been made to correct the steering amount and the reaction force to the steering according to the running state of the vehicle. For example, Japanese Patent Application Laid-Open No. 64-60475 and Japanese Utility Model Application Laid-Open No. 63-124571 disclose a device for automatically correcting the steering amount, the steering angle, etc. at the turning limit of the vehicle, and Japanese Patent Application Laid-Open No. 3-112777. The publication discloses a technique in which the assist force of power steering is controlled according to the slip state of the drive wheels to allow the driver to sense a change in the running state.

Further, in Japanese Unexamined Patent Publication No. 4-133864, there is provided an actuator for applying a reaction force to the steering wheel, and the operation reaction force is rapidly increased in the vicinity of the maximum turning angle of the traveling wheels, so that the driver is A technique for recognizing a steering lock state is disclosed.

[0005]

However, in the above-mentioned conventional traveling vehicle, the driver on board detects a danger such as contact or collision with an obstacle, and shows a reaction to avoid them. In such a case, there is no room for the driver to intervene in the steering, and the vehicle itself does not actively indicate the direction in which the steering should be operated in response to the driver's reaction, so it is not possible to ensure driving safety. There's a problem.

[0006]

The present invention has been made for the purpose of solving the above-mentioned problems, and is provided with the following structure as means for solving the above-mentioned problems. That is, in a steering assist device for a vehicle equipped with an actuator for steering by a driver or receiving a predetermined control signal, a means for detecting the steering state of the driver and a means for recognizing the environment of the vehicle. Based on the recognition result, determination means for determining the risk to the vehicle, means for driving the actuator according to the risk,
First control means for realizing a mode in which only a predetermined alarm is issued and the actuator is not driven according to the risk level; and a predetermined alarm according to the risk level And a second control means for realizing a mode in which a danger is notified in response to the driver's steering state, and the actuator is driven so as to reduce the danger level in accordance with the danger level. And a third control means for implementing a mode in which steering by the driver is prioritized over driving of the actuator, and fourth control means for only driving the actuator according to the level of the risk.

Preferably, the second control means gives the danger notice only when the driver steers in a direction in which the degree of danger increases. Further, preferably, the third control means maintains the steering by driving the actuator when the driver steers in a direction in which the degree of danger is reduced.

[0008]

With the above structure, the vehicle functions to ensure the safety of running of the vehicle.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a block diagram showing the overall configuration of a vehicle steering assist device (hereinafter referred to as a device) according to an embodiment of the present invention. In the figure, the sensor 1
Detects the distance between an obstacle (not shown) and the vehicle and the traveling speed of the vehicle, and sends the detection result to the recognition unit 2. In the recognition unit 2, the detection result of the sensor 1 and the torque sensor 7
In response to the operation state of the steering by the driver detected in, the degree of danger for the situation of the own vehicle, which will be described later, is calculated.

The determination unit 3 also determines an operation for steering assistance based on the degree of danger calculated by the recognition unit 2. Then, the control unit 4 sends a drive signal to the actuator 6 based on the determination made by the determination unit 3 to realize desired steering assistance. As will be described later, the determination unit 3 has a mode in which the present device does not intervene in steering depending on the degree of danger, and in that case, the alarm unit 8 is driven to give a predetermined warning to the driver. Present.

Therefore, the steering assist mode in the apparatus of this embodiment will be described. In the device according to the present embodiment, as shown below, the degree of positive steering of the driver, in other words,
The steering assist modes are classified according to the degree to which the device itself does not interfere with steering. (1) Completely manual mode: The device simply notifies the driver of the danger by displaying an alarm and does not intervene in steering. That is, the steering by the driver directly determines the behavior of the vehicle.

(2) Semi-manual mode: In addition to displaying an alarm, the device notifies the driver of danger by changing the assisting operation, that is, the reaction force and gain to the steering. In this case, since the device responds to the steering of the driver, when there is no change in the steering of the driver, it is equivalent to the above complete manual mode, but when the driver performs some steering operation, The driver can sense the intention of the device through the steering system.

The change in the reaction force and the gain with respect to the steering here is realized by driving the actuator 6 shown in FIG. (3) Semi-automatic mode: The device performs automatic steering so that the degree of danger is reduced, but when the driver performs a steering contrary to the intention of the device, the steering is prioritized. Also in this mode, as in the above-mentioned semi-automatic mode, the assist operation is simultaneously performed.

(4) Fully automatic mode: The device automatically performs steering to avoid a dangerous state such as collision or contact with an obstacle. In this case, the steering of the driver is ignored.
In the present embodiment, the determination unit 3 selects one of the four modes according to the detected risk level and assists the driver in steering. Specifically, as shown in FIG. 2, the degree of danger and the steering assist mode are made to correspond in stages based on a predetermined threshold value set in advance.

In the selection of the steering assist mode described above, as shown in FIG. 2, the range 0 to 1 of the total risk is set to the threshold values Th1 to Th.
The above four modes are associated with each division. For example, for a driver with high driving skill (skill), there is a high possibility that safe driving of the vehicle will be performed even if the driver turns the steering wheel to a high risk level. Since it is considered that the driver prefers to steer and drive, these threshold values are set so that the device performs an operation that matches the feeling of the driver. Therefore, all thresholds are set high for a driver with high skill.

Next, the method of calculating the risk in this embodiment will be described in detail. In the present embodiment, the recognition unit 2 shown in FIG. 1 calculates the degree of danger, which is an index indicating how dangerous the own vehicle is to an obstacle, by the method described below. That is, the recognizing unit 2 calculates the degree of danger according to the degree of danger classified based on the speed and running state of the own vehicle, and a total of seven degree of danger classification into which the degree of danger is further finely classified.

[0017] As risk here is, (A) the current status of the vehicle, that is, this risk in the current running state, further, the position risk with the current position of the vehicle (part vector value a ₁₀ And the speed risk (a ₁₁ ) depending on the traveling speed of the own vehicle.

(B) Risk Factor Based on Vehicle Performance This is a risk factor due to the function and performance originally possessed by the vehicle. For example, the risk factor based on the steering performance due to the limit of the steering angle of the steering wheel (a ₁₂ ), And the degree of risk based on the acceleration / deceleration performance of the vehicle (a ₁₃ ) (C) The degree of risk attributable to the driver's skill, specifically, the degree of risk (a ₁₄ ) due to the operation delay (response time) that the driver potentially has ) (D) Risk degree from the current state of the vehicle to the future driving state This is, in other words, the risk degree depending on the driver's willingness to drive, and the future position risk degree (a ₁₅ ) depending on the future position of the vehicle , And the future speed risk (a ₁₆ ) depending on the future speed of the vehicle.

Therefore, in this embodiment, the vector value a _10-
7 consisting of the above seven risk levels represented by a ₁₆
The following risk level vector A _i is defined by the following equation (1). In addition, each of the above-described degrees of danger is standardized as 1 when there is the highest possibility of falling into a dangerous state due to contact with an obstacle or the like. _{A i = (a 10, a} 11, a 12, a 13, a 14, a 15, a 16) ... (1) Furthermore, the weight sum W _i of risk vector _{A i, W i = K ·} A i ^t ... (2) Here, K is a weight vector representing the importance of each risk and can be changed according to the situation.

The weight sum W _i represents the degree of danger of an obstacle with respect to the own vehicle, and the greater the value, the greater the degree of danger of the obstacle with respect to the own vehicle. Further, P = ΣW _i (3), which is a value obtained by adding the weight sum W _i of each risk vector to all obstacles, represents the overall risk of the host vehicle. The recognition unit 2 illustrated in FIG. 1 outputs the calculated risk levels to the determination unit 3.

Next, a specific method of calculating the above-mentioned risk levels will be described individually. (A) Positional risk Usually, there is a potential risk with respect to the distance to an obstacle. For example, if the vehicle approaches the obstacle too much, the field of view in front of the host vehicle is obstructed, and a risk factor such as deterioration of the visual field occurs. Therefore, in this embodiment, as shown in FIG.
To avoid these risk factors, the minimum distance is L, the distance measured by the sensor is R, and the measurable range of the sensor is S.
_The following risk levels are set as _{min to} S _max .

As described above, the sensor for measuring the distance has a measurable range. For example, in the ultrasonic sensor, it is 20
It is difficult to detect obstacles located at a distance of cm or less and 10 m or more. If the distance measurement result is out of the above range, the reliability is low, and therefore the measurable range must be taken into consideration when calculating the risk.

In the device according to the present embodiment, when the distance measurement result is S _min or less, the reliability of the result is low, but it is judged that there is a high possibility that an obstacle is present near the own vehicle, and it is dangerous. The degree is 1. Also, when the measurement result is S _max or more,
Although the reliability of the result is low, it is unlikely that there is an obstacle in the vicinity, so the risk is set to the lowest level (corresponding to the potential risk shown in FIG. 3, and the risk there is not 0).

When the measurement result is in the range of S _{min to} L in FIG. 3, the risk decreases as the distance increases,
As compared with the case where the measurement result is in the range of L to S _max , the risk attenuation rate is smaller, so in the above two ranges, functions with different attenuation rates are set as shown in FIG. Note that FIG.
In the function shown in (1), L is the minimum distance required to avoid danger, so that the characteristic is such that the risk level increases dramatically in the direction in which the measurement distance becomes shorter. (B) Speed Danger FIG. 4 shows the characteristics of the function for calculating the speed risk in the present embodiment, in which the obstacle is distant from the own vehicle,
That is, dR / dt, which is the change over time with distance, is (dR /
When dt)> 0, the risk is low, and conversely (dR / dt) <0
Then, there is a high degree of danger because obstacles are approaching. (C) Risk Based on Steering Performance Here, the maximum steering angle of the vehicle is used as an element for evaluating steering performance. The recognition unit 2 calculates the minimum steering angle necessary for avoiding obstacles, applies the result to the characteristic curve shown in FIG. 5, and the calculated minimum steering angle is the maximum steering angle of the vehicle. The degree of risk is calculated by whether or not it exceeds. When the required minimum steering angle exceeds the maximum steering angle of the vehicle, the obstacle cannot be avoided only by the steering operation, so the degree of danger in this case is set to 1.

Specifically, when the maximum steering angle at which the vehicle cuts is 45 ° and the system determines that a steering angle of 60 ° is necessary to avoid danger, the degree of danger becomes 1. . (D) Risk Level Based on Vehicle Acceleration / Deceleration Performance The maximum deceleration is used here to evaluate the vehicle acceleration / deceleration performance. For example, the recognition unit 2 assumes that an obstacle ahead stops suddenly, and calculates the maximum reduction speed for preventing the vehicle from colliding with the obstacle. Then, the value is shown in FIG.
In the case where the required minimum deceleration exceeds the maximum deceleration in light of the characteristic curve shown in (1), for example, the obstacle cannot be avoided only by the brake operation.
To (E) Risk due to driver's operation delay (response time) This risk is based on the risk of driver's reaction delay up to obstacles, assuming that the current speed is maintained within the response time. It is calculated based on whether or not the distance is sufficient.
Here, the response time is defined as the sum of the driver's situation determination time (measured in advance) and the idle time of the vehicle, and is defined as T. Also, the current speed of the host vehicle is V, up to an obstacle. When the distance is R, the risk D can be expressed by D = (T · V) / R (4). However, when D> 1, the values are rounded to D = 1.

In this case, the degree of danger 1 means that the speed of the obstacle suddenly becomes 0, and even if the driver decelerates at the maximum deceleration, there is a response time and the vehicle collides with the obstacle. To do. (F) Future Position Danger and Future Velocity Danger These are the risks due to the driver's willingness to drive as described above, and the future position and speed of the host vehicle are calculated from the present vehicle speed and the steering angle. For these, the position risk and the speed risk are calculated in the same manner as the position risk calculation in (a) above. In other words, these risks can be rephrased as the future risks of the obstacle position with respect to the traveling direction of the own vehicle having a certain speed, and predicting the future position and speed of the own vehicle is indirectly The current driving intention of the driver will be detected.

Therefore, as shown in FIG. 7, the preview time for predicting the future position and speed of the own vehicle is τ, the distance of the future position of the own vehicle to the current obstacle position is R ′, and the current own vehicle is When the distance between the vehicle position and the current obstacle position is R, the temporal change r of the distance is defined by r = (RR ′) / τ (5), so this value is small. The higher the risk.

As described above, according to this embodiment,
The vehicle calculates the degree of danger to obstacles according to the driving conditions and the reaction of the driver, actively presents the driver with the direction in which the steering should be operated, and judges that the degree of danger has reached the maximum. In this case, it is possible to ensure the safety of the vehicle running by rejecting the intervention of the driver and executing the fully automatic steering.

[0029]

As described above, according to the present invention,
There is an effect that the safety of the vehicle can be secured by assisting the steering while respecting the driver's will according to the determined risk level.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of a steering assist device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a correspondence between a steering assist mode and a threshold value in the device according to the embodiment.

FIG. 3 is a diagram showing a function characteristic for calculating a position risk in the example.

FIG. 4 is a diagram showing a function characteristic for calculating a speed risk in the embodiment.

FIG. 5 is a diagram showing characteristics for calculating a risk degree based on steering performance in the embodiment.

FIG. 6 is a diagram showing characteristics for calculating a risk degree based on acceleration / deceleration performance in the example.

FIG. 7 is a diagram for explaining a method of calculating a future traveling state in the embodiment.

[Explanation of symbols]

 1 Sensor 2 Recognition Part 3 Judgment Part 4 Control Part 5 Steering 6 Actuator 7 Torque Sensor 8 Alarm Part

Claims (10)

[Claims] 1. A steering assist device for a vehicle, comprising an actuator for a driver to steer or to receive a predetermined control signal to carry out the steering, wherein a means for detecting a steering state of the driver and a vehicle environment are provided. A means for recognizing, a determination means for determining the degree of danger to the vehicle based on the recognition result, a means for driving the actuator according to the degree of danger, and a predetermined degree according to the stage of the degree of danger. First control means for realizing a mode in which only an alarm is issued and the actuator is not driven, and a predetermined alarm is issued according to the stage of the danger level and the driver reacts to the steering state. A second control means for realizing a danger notification mode, and the actuator is driven so that the danger level is reduced in accordance with the risk level, and the driver is instructed to do so. A third control means for realizing a mode for prioritizing steering to drive the actuator, and a fourth control means for only driving the actuator according to the level of the risk. Car steering assist device. 2. The steering assist device for an automobile according to claim 1, wherein the second control means gives the danger notification only when a driver steers in a direction in which the degree of danger increases. 3. The steering assist system for a vehicle according to claim 1, wherein the danger notification is an increase in a reaction force of steering. 4. The steering assist device for a vehicle according to claim 1, wherein the danger notification is a change in steering gain. 5. The third control means maintains the steering by driving the actuator when the driver steers in a direction in which the risk level decreases. Steering aids for automobiles. 6. The steering assist device for a vehicle according to claim 1, wherein the determination means determines a vehicle position risk as a risk. 7. The steering assist device for a vehicle according to claim 1, wherein the determination means determines a speed risk of the vehicle as a risk. 8. The steering assist system for a vehicle according to claim 1, wherein the determination unit determines the degree of danger based on a steering characteristic of the vehicle. 9. The steering assist system for a vehicle according to claim 1, wherein the determination unit determines the degree of danger based on the acceleration / deceleration performance of the vehicle. 10. The vehicle steering assist device according to claim 1, wherein the determination unit determines the degree of danger based on a driver's operation skill.