JPH10250614A - Steering device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately avoid the risk by finding a resistance corresponding value corresponding to the resistance degree of a driver to a steering regulation, judging whether the resistance corresponding value is a set value or more, and providing a means for releasing the steering suppression, when the resistance corresponding value is the set value or more. SOLUTION: When a time integral value from the start of a steering suppression of a steering input torque detected by a torque sensor 3 is a set value or more, a controller 50 releases the steering suppression and a warning. A steering input torque acted by a driver by resisting to the steering suppression is an inverse code to the additional torque for the steering suppression and changes according to the additional torque so that the time integral value from the start of the steering suppression of the steering input torque is gradually increased. This constitution causes the necessity of steering in steering suppression and, when the driver is resisted to the steering suppression the steering suppression is released.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle steering system capable of preventing a running vehicle from colliding with an obstacle such as another vehicle.

[0002]

2. Description of the Related Art The purpose of the present invention is to prevent a vehicle from colliding with an obstacle such as another vehicle on the side or rear side when changing lanes or the like. 2. Description of the Related Art There has been proposed a steering device which is provided with a sensor for detecting an obstacle on the rear side and performs steering suppression based on the possibility of collision between the vehicle and the obstacle.

[0003] However, if an emergency situation occurs during steering suppression, for example, a situation in which an obstacle ahead suddenly appears, it is necessary to cancel the steering suppression.

In order to cope with such an emergency, not only sensors for detecting side and rear obstacles but also sensors for detecting a forward obstacle are provided, and a lateral obstacle immediately after the detection of a forward obstacle is provided. It is conceivable to perform control such as ignoring object detection. However, in this case, a sensor for detecting a forward obstacle is indispensable, which is expensive.

[0005] In addition, there has been proposed a technique in which a degree of danger is obtained from a change in the surrounding environment of the vehicle and the steering control mode is switched to an automatic mode, a semi-automatic mode, or the like in accordance with the degree of danger (Japanese Patent Laid-Open No. 7-47967). ). However, since the surrounding environment needs to be detected, the system becomes large,
It will be very expensive.

An object of the present invention is to provide a vehicle steering system that can solve the above-mentioned problems.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a vehicle steering system capable of suppressing steering based on the possibility of collision with an obstacle. And determining whether the resistance corresponding value is equal to or greater than a set value, and releasing the steering suppression when the resistance corresponding value is equal to or greater than the set value.
As a result, a need arises to perform steering against steering suppression, and when the driver resists steering suppression, the steering suppression can be released. In this case, the steering suppression is released when the resistance corresponding value corresponding to the degree of resistance of the driver is equal to or greater than the set value, so that the steering suppression can be released earlier as the urgency of the release of the steering suppression becomes higher. Become.

It is preferable that a value corresponding to a time integrated value of the driver's resistance from the start of the steering suppression be obtained as the driver's resistance corresponding to the steering suppression. As a result, the time until the steering suppression is released can be shortened as the driver's resistance to the steering suppression increases, and it is possible to cope with a change in the urgency level during the steering suppression.

It is preferable to obtain a value corresponding to the driver's resistance as the driver's resistance corresponding to the steering suppression. Thus, in an emergency where it is highly necessary to release the steering suppression, the driver can quickly release the steering suppression by applying a large resistance. Therefore, when the necessity of the steering suddenly increases during the steering suppression, the steering suppression is promptly released due to an increase in the resistance force applied by the driver, thereby preventing a delay in the steering. Also, since the driver's intention to release the steering suppression can be promptly reflected, it is possible to prevent the steering wheel from being returned excessively in the direction opposite to the direction in which a collision may occur.

It is preferable to provide a means for changing the set value according to the characteristics of the driver. For drivers with relatively strong power or drivers who steer relatively sharply due to rough driving, increase the set value, while drivers with relatively weak power or steering relatively slowly For the driver, the set value can be reduced, and the steering suppression can be appropriately released in accordance with the characteristics of the driver.

It is preferable to provide a means for changing the set value according to the vehicle speed. Thus, by reducing the set value at a high speed and increasing the set value at a low speed, it is possible to release the steering suppression at an appropriate timing according to the vehicle speed.

A vehicle steering system according to the present invention comprises means for assisting steering and means for determining an urgency level of steering. When the urgency level of the steering is equal to or higher than a set level, the steering assist force is reduced. Preferably it is possible. According to this configuration, when sudden steering is performed, the steering assist force can be reduced. This makes it possible to prevent the vehicle behavior from becoming unstable when the vehicle is steered suddenly in the opposite direction after the steering is suppressed by steering in the direction in which a collision is likely to occur. Further, even when steering is performed very rapidly to avoid an obstacle in front of the vehicle, it is possible to prevent the steering from being performed too rapidly and to stabilize the behavior of the vehicle.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

First, when a vehicle equipped with an electric power steering apparatus to which the present invention is applied and a lane change is performed, the urgency level of the steering and the amount of change in the steering output torque within a set time from the start of the steering are determined. The relationship was determined by experiment. FIG. 1 shows the results of the experiment. In addition,
In the present specification, the change acceleration of the steering output torque refers to a second-order differential value of the time of the steering output torque, and the change speed of the change acceleration of the steering output torque refers to the time of the change acceleration of the steering output torque. The differential value of

The horizontal axis in FIG. 1 indicates a vehicle speed of 50 km /
The time (seconds) required to move the first 1 m when changing lanes 3.5 m in the horizontal direction at the time. The shorter the time, the higher the urgency level.

The vertical axis in FIG. 1 indicates the amount of change (N · m) of the steering output torque during a set time (0.1 seconds) from the start of steering. The steering output torque changes before the turning angle of the wheel actually changes. The set time is, as described later, when standard steering is performed,
It is preferable to set as short as possible as long as the change amount of the steering output torque within the set time from the start of the steering can be associated with the urgency level of the steering.

In FIG. 1, the data of the experimental results are plotted with "●" and "△". Data a to v indicated by “●” indicate results of standard steering. Data [alpha] to [epsilon] indicated by "[Delta]" indicate the results of irregular steering. Here, the standard steering refers to steering that is performed naturally without intentionally changing the steering speed from the start to the end of the lane change. In addition, irregular steering refers to steering performed by intentionally changing the steering speed at the beginning of the lane change.

From the standard steering data a to v shown in FIG. 1, when standard steering is performed at the time of lane change, the amount of change in steering output torque within a set time from the start of steering and the urgency of steering You can see that there is a correspondence with the level. In this experiment, the steering urgency levels are classified into four levels. That is, the data a to g are “urgent” having the highest urgency level, the data h and i are “quick” having the second highest urgency level, and the data j to s are “urgent” having the third highest urgency level. "Normal", data tv
Is classified as a boundary between “normal” and “slow” having the lowest urgency level.

On the other hand, the irregular steering data α to ε shown in FIG.
Thus, when irregular steering is performed at the time of lane change, it can be confirmed that there is no correspondence between the emergency level of steering and the amount of change in steering output torque within a set time from the start of steering. That is, the data α is to be classified as “quick” from the urgency level corresponding to the time required for the lane change, but since the steering is intentionally performed only immediately after the start of the lane change, It is classified as "urgent" based on the amount of change in the steering output torque within a set time from the start of steering. The data β should be classified as “quick” from the urgency level corresponding to the time required for the lane change, but the steering at normal speed is intentionally performed only immediately after the start of the lane change. Therefore, the steering output torque is classified as “normal” from the amount of change in the steering output torque within the set time from the start of steering. Although the data γ and δ should be classified as “normal” from the urgency level corresponding to the time required for the lane change, relatively quick steering is intentionally performed only immediately after the start of the lane change. Therefore, it is classified as “quick” from the amount of change in the steering output torque within a set time from the start of steering. Also, the data ε should be classified as “normal” from the urgency level corresponding to the time required for the lane change, but intentionally perform relatively gentle steering only immediately after the start of the lane change. Therefore, the steering output torque is classified into the boundary between “normal” and “slow” based on the amount of change in the steering output torque within the set time from the start of steering.

Next, when changing lanes, the urgency level of steering and the set time (0.1
The relationship between the steering output torque and the change acceleration of the steering output torque at the elapse of the second) was obtained by an experiment using a vehicle equipped with the same electric power steering device. FIG. 2 shows the results of the experiment.
Each data of the experimental result of FIG. 2 corresponds to each data of the experimental result of FIG.

The horizontal axis in FIG. 2 is a vehicle speed of 50 km / km.
In the case where a lane change of 3.5 m is made in the lateral direction, the time required to move the first 1 m is shown. The vertical axis in FIG. 2 indicates the change acceleration (N · m / s ² ) of the steering output torque at the time when 0.1 second has elapsed from the start of steering.

In FIG. 2, the data of the experimental results are represented by "●", the results obtained by performing standard steering in the same manner as in FIG.
Then, the results of the irregular steering are plotted with “△”, and the data symbols a to v and α to ε correspond to the data symbols of FIG.

From the standard steering data a to v shown in FIG. 2, when the standard steering is performed at the time of lane change, the correspondence between the urgency level of the steering and the change acceleration of the steering output torque is shown. You can see that there is. That is, the data a to g are “urgent” having the highest urgency level, the data h and i are “quick” having the second highest urgency level,
Data j to s are "normal" with the third highest urgency level
In addition, the data t to v are classified into a boundary between “normal” and “slow” having the lowest urgency level. The change acceleration at the boundary between the urgency level “normal” and “slow” is set to zero.

On the other hand, the irregular steering data α to ε shown in FIG.
From this, it can be confirmed that when irregular steering is performed when changing lanes, the urgency level of steering does not necessarily correspond to the change acceleration of the steering output torque. That is, the data α is to be classified as “quick” from the urgency level corresponding to the time required for the lane change, but since the steering is intentionally performed only immediately after the start of the lane change, The urgency level corresponding to the change acceleration is classified into a boundary between “quick” and “normal”. In the data α, the urgency level corresponding to the amount of change in the steering output torque within the set time from the start of steering is classified as “urgent,” and the degree of the urgency level is determined by the change acceleration of the steering output torque. The urgency level corresponding to is lower. The data β should be classified as “quick” from the urgency level corresponding to the time required for the lane change, and the steering is intentionally performed at a normal speed only immediately after the start of the lane change. However, the urgency level corresponding to the change acceleration of the steering output torque is classified as “quick”. This data β
Since the urgency level corresponding to the amount of change in the steering output torque within the set time from the start of steering is classified as “normal”, the degree of the urgency level corresponds to the change acceleration of the steering output torque. The urgency level is higher. Although the data γ and δ should be classified as “normal” from the urgency level corresponding to the time required for the lane change, relatively quick steering is intentionally performed only immediately after the start of the lane change. Therefore, the urgency level corresponding to the change acceleration of the steering output torque is “normal”
And “quick” boundaries. The data γ and δ indicate that the urgency level corresponding to the change amount of the steering output torque within the set time from the start of the steering is “quick”.
The urgency level corresponding to the change acceleration of the steering output torque is lower than the urgency level. The data ε should be classified as “normal” from the urgency level corresponding to the time required for the lane change, and relatively gentle steering is intentionally performed only immediately after the start of the lane change. However, the urgency level corresponding to the change acceleration of the steering output torque is also classified as “normal”. In the data ε, the urgency level corresponding to the change amount of the steering output torque within the set time from the start of steering is classified into a boundary between “normal” and “slow”. The urgency level corresponding to the change acceleration of the steering output torque is higher.

Next, the data k, o, n, ε, r, t, u and v whose urgency level corresponding to the change acceleration of the steering output torque is close to the boundary between “normal” and “slow”. In consideration of the change speed of the change acceleration, the steering output torque at the time when the set time (0.1 second) has elapsed since the start of the steering and at the time when the set time (0.4 second) has further elapsed is calculated. The further set time is determined for each data k, o, n,
It is preferable to set as short as possible as long as the differences in the urgency levels of ε, r, t, u, and v can be identified as follows. Comparing the calculation result with the steering output torque at the lapse of 0.1 seconds from the start of steering, data k, o, and k having high urgency level corresponding to the time required for lane change
As for n and ε, as shown by arrows in FIG. 2, the steering output torque increases, and data r, t, u, and v with low urgency levels corresponding to the time required for lane change are:
As shown by the arrow in FIG. 2, the steering output torque decreases. That is, when the steering urgency level is at or near the boundary between the two urgency levels, the steering output torque at the elapse of the set time from the start of the steering increases when the steering output torque decreases, rather than decreases. Is high. The area near the boundary of the steering urgency level where this relationship holds,
In the present specification, the vicinity of the boundary of the urgency level is set, and the range from the specific boundary can be obtained by experiments.

Next, when entering a curve,
The relationship between the change amount of the steering output torque within a set time from the start of steering and the change acceleration of the steering output torque at the elapse of the set time was obtained by an experiment using a vehicle equipped with an electric power steering device. FIG. 3 shows the results of the experiment.

The horizontal axis in FIG. 3 is a vehicle speed of 50 km / km.
Change in steering output torque in 0.1 second from the start of steering for entering the curve when passing through a curve with a constant turning radius without deceleration (Nm)
Is shown. The vertical axis indicates the set time (0.
1 second), the change acceleration of the steering output torque (10N
· M / s ² ).

In FIG. 3, the data of the experimental results at the time of entering the curve are plotted with “●” and “□”. The data indicated by “●” indicates the result of performing standard steering. Data indicated by “□” indicates the result of irregular steering. Here, the standard steering refers to steering that is performed naturally without intentionally changing the steering speed when entering a curve. In addition, irregular steering refers to steering that intentionally speeds up steering when entering a curve.

FIG. 3 also shows the relationship between the amount of change in the steering output torque within a set time from the start of steering and the acceleration of the change in the steering output torque at the elapse of the set time when the lane is changed. Shown. As the data when the lane change is performed, data indicating that the urgency level of the steering is classified as “normal” is “○”, and data classified at the boundary between “normal” and “slow” is “△”. ".

From the standard steering data shown in FIG. 3, it can be confirmed that when standard steering is performed at the time of entering a curve, the change acceleration of the steering output torque becomes substantially zero or less. This is because the driver tries to keep the steering speed constant when trying to faithfully follow the lane at the beginning of the curve, or performs corrective steering to reduce the steering angle when the steering angle becomes excessive. Therefore, the substantially zero value of the change acceleration of the steering output torque becomes a threshold value for determining whether or not the steering purpose is going into a curve, and the threshold value can be experimentally set in advance.

The data of the curve entry by the standard steering is based on the change amount of the steering output torque and the acceleration of the change of the steering output torque. It is smaller than the boundary with "slow" and cannot be distinguished from data whose change acceleration is equal to or less than a threshold value of substantially zero. Then, when the value of the change acceleration of the steering output torque after a set time (0.1 second) elapses is obtained, the value decreases monotonically in the case of a lane change, while it decreases or increases monotonically in the case of entering a curve. Met. The set time is set as short as possible as long as it is possible to distinguish between entering a curve and changing lanes.

On the other hand, based on the irregular steering data shown in FIG. 3, when the irregular steering is performed when entering the curve, that is, when the steering wheel is intentionally sharply turned at the beginning of the steering, the steering It can be confirmed that the change acceleration of the output torque becomes larger than the substantially zero threshold value.

The data of the curve entry due to the irregular steering is based on the amount of change of the steering output torque and the acceleration of the change of the steering output torque. Therefore, it cannot be distinguished from those in which the change acceleration exceeds a substantially zero threshold value. Then, when the increase or decrease of the change acceleration of the steering output torque within the subsequent set time is obtained, it does not decrease when changing lanes, but decreases when entering a curve. This is because if the steering wheel is intentionally sharply turned in the case of entering a curve, the course correction steering is required thereafter. The set time is set as short as possible as long as it is possible to distinguish between entering a curve and changing lanes.

From the above, the amount of change in the steering output torque within the set time from the start of steering, the change acceleration of the steering output torque at the time when the set time has elapsed, and the subsequent setting of the steering output torque at the time when the set time has elapsed from the start of steering. The urgency level of the steering can be determined based on the increase / decrease in time and the increase / decrease in the change acceleration of the steering output torque within the subsequent set time, and further, the purpose of the steering can be determined.

The rack and pinion type electric power steering device 1 shown in FIG.
And an output shaft 4 connected to the input shaft 2 via a torque sensor 3. The steering input torque transmitted from the input shaft 2 to the output shaft 4 is detected in time series by the torque sensor 3. Its output shaft 4
Is connected to a pinion 6, and a steering wheel 8 is connected to a rack 7 that meshes with the pinion 6. Thus, the steering input torque is transmitted to the rack 7 via the steering wheel H, the input shaft 2, the torque sensor 3, the output shaft 4, and the pinion 6, and the vehicle A is steered by the movement of the rack 7.

A part of the rack 7 is a ball screw 2
A gear is formed on the outer periphery of a ball nut 22 that meshes with the ball screw 21, and a drive gear 25 meshes with a gear 24 that meshes with the gear. The drive gear 25 is rotationally driven by a DC servo motor 13 which is an actuator for steering assistance and steering suppression. Thereby, the additional torque generated by the motor 13 is transmitted to the rack 7.

From the steering wheel H to the rack 7
The sum of a value obtained by multiplying the gear ratio up to the steering input torque and a value obtained by multiplying the reduction ratio from the output shaft of the motor 13 to the rack 7 by the output torque of the motor 13 corresponds to the steering output torque. In the present embodiment, the steering input torque is detected by the torque sensor 3 as described above as a value corresponding to the steering output torque. The steering output torque is associated with the steering input torque from the relationship between the steering input torque and the steering output torque stored in the controller 50 described later.

The torque sensor 3 is connected to a controller 50 constituted by a computer. The controller 50 includes the motor 13 and the vehicle speed detection sensor 5.
1. A plurality of obstacle detection sensors 5 attached to the vehicle A
3, 54, 55, 56 and voice alarm 52 are connected. These obstacle detection sensors 53, 54, 55,
56, for example, to detect obstacles on the left and right sides and rear left and right sides of the vehicle A, a transmitter that emits radar waves such as lasers and ultrasonic waves from the vehicle, and a receiver of the radar waves, And an amplifier for the received radar wave, and the controller 50 detects the time difference between the transmission and reception of the radar wave.
, Which can calculate the distance to the obstacle.

The controller 50 stores, as a part of a control program, a predetermined correspondence relationship between the amount of change in the steering output torque and the urgency level of the steering within a set time from the start of the steering. And a predetermined correspondence between the steering urgency level and the steering urgency level are stored. In the present embodiment, the urgency levels in the stored correspondence are four levels of “urgent”, “quick”, “normal”, and “slow” as described above.

Further, the controller 50 determines the maximum value of the absolute value of the steering output torque To, the maximum value of the absolute value of the change acceleration of the steering output torque To, and the value of the steering input torque Ti as values corresponding to the characteristics of the driver. The maximum absolute value is stored. These values increase for a driver with relatively strong power or a driver who performs rough driving, and decrease for a driver with relatively low power or a driver who performs steering relatively slowly.

For example, as shown in Table 1 below, any one of an upper limit value P1 and a lower limit value P2 of the maximum value P of the absolute value of the steering output torque To, and the change acceleration of the steering output torque To Of the absolute value of the maximum value Q between the upper limit value Q1 and the lower limit value Q2 and the absolute value of the steering input torque Ti between the upper limit value R1 and the lower limit value R2 of the maximum value R. Are stored in correspondence with the strength of the characteristic level of the driver. The upper limit value P1, Q1, R1 and the lower limit value P
2, Q2 and R2 may be obtained by experiments using drivers having different characteristics. Note that the steering output torque To
Of the absolute value of the steering output torque To, the maximum value P of the absolute value of the change acceleration of the steering output torque To, and the maximum value R of the absolute value of the steering input torque Ti are updated based on the actual steering of the driver as described later. However, the lower limit value P2 corresponding to the case where the characteristic level of the driver is the weakest,
Q2 and R2 are stored.

Further, the strength of the driver characteristic level corresponds to the judgment criterion of the urgency level, the steering suppression strength, and the set value Y to be compared with the driver's resistance corresponding value to the steering suppression. In other words, the stronger the driver characteristic level, the higher the criterion for determining the urgency level,
The steering suppression strength is large, and the set value Y is increased. As a result, drivers with relatively strong power or those who steer relatively quickly can use "emergency", "quick",
The change amount of the steering output torque and the change acceleration of the steering output torque, which are the criteria for determining the boundary between the “normal” and “slow” urgency levels, are increased, and the torque added by the motor 13 for steering suppression is increased. And the set value Y is increased. Conversely, for a driver having a relatively weak force or a driver performing steering relatively slowly, the amount of change in the steering output torque or the change acceleration of the steering output torque, which is the criterion, is reduced, and the additional torque by the motor 13 is reduced. The set value Y is reduced. Correspondence relationship between the change amount of the steering output torque, which is the criterion for determining the boundary of the urgency level, and the driver characteristic level, and the correspondence between the change acceleration of the steering output torque, which is the criterion for determining the boundary of the urgency level, and the driver characteristic level The relationship, the corresponding relationship between the steering suppression strength and the driver characteristic level, and the corresponding relationship between the set value Y and the driver characteristic level are respectively set in the controller 50.
Is stored. Each correspondence may be obtained by an experiment using drivers having different characteristics.

[0043]

[Table 1]

The controller 50 performs the following steering assist control and steering suppression control in accordance with the stored control program. Hereinafter, the control procedure will be described with reference to flowcharts shown in FIGS.

First, the torque sensor 3 and the vehicle speed detection sensor 5
1. Start reading signals from the obstacle detection sensors 53, 54, 55, 56 in time series (step 1).

Next, a drive control current value of the motor 13 is calculated (step 2). The drive control current value of the motor 13 corresponds to the additional torque generated by the motor 13. FIG.
As shown in the relationship between the steering input torque Ti and the steering output torque To at 0, during the steering assist, the driving of the steering output torque To is increased such that as the detected steering input torque Ti increases, the steering output torque To increases. The control current value is determined. Further, the drive control current value of the motor changes depending on the detected vehicle speed. That is, in the low-speed V1 state, the steering output torque To is increased to improve the turning performance of the vehicle, and in the high-speed V2 state, the steering output torque To is reduced to improve the stability during high-speed running. The steering input torque T
The relationship between i and the steering output torque To is predetermined and stored in the controller 50.

Next, the obstacle detection sensors 53, 54,
Based on the obstacle detection signals from 55 and 56, it is determined whether an obstacle such as a nearby vehicle has been detected within a predetermined distance from the vehicle A (step 3).

When an obstacle is detected in step 3, whether or not a change in the steering output torque To corresponding to the detected steering input torque Ti within a set time exceeds a set value indicates whether or not the vehicle is traveling normally. That is, it is determined whether the vehicle is traveling at a substantially constant steering angle (step 4). The set time and set value are predetermined and stored in the controller 50. Note that the steering output torque To slightly fluctuates even in a steady state due to the influence of disturbance due to irregularities on the road surface and the like and the influence of electric noise on the torque sensor 3.
Has.

When the steering is started after it is determined in step 4 that the vehicle is traveling normally, the steering input torque Ti
, The change in the steering output torque To within the set time exceeds the set value. In this case, based on the sign of the steering output torque To, it is determined whether the steering start direction is the direction of the detected obstacle, that is, the vehicle A
It is determined whether there is a possibility of collision with the obstacle (step 5).

In step 5, if the steering direction is the direction of the detected obstacle, that is, if there is a possibility of collision, the steering urgency level is determined as the steering state based on the steering output torque corresponding to the detected steering input torque. A determination is made (step 6).

FIG. 8 shows a procedure for determining the urgency level of the steering.
Is shown in the flowchart of FIG. First, an urgency level corresponding to the amount of change in the steering output torque To within a set time from the start of steering, and the steering output torque T at the time when the set time has elapsed.
It is determined whether or not the urgency level corresponding to the change acceleration o matches (step 101). For this judgment,
When the set time has elapsed, the controller 50 calculates the steering output torque To at the start of steering and the steering output torque T at the elapse of the set time from the steering input torque Ti read in time series.
By calculating the difference from o, the amount of change in the steering output torque To is obtained, and the change acceleration corresponding to the second derivative of the steering output torque To at the time when the set time has elapsed is calculated.

As a result of the determination, when the two urgency levels match, the urgency level is determined as a provisional determination result (step 102). When the two urgency levels do not match, the emergency corresponding to the change acceleration is determined. The degree level is set as a provisional determination result (step 103).

Next, it is determined whether or not the urgency level based on each provisional determination result is at or near the boundary between the two urgency levels (step 104).

As a result of the judgment, if the urgency level based on the provisional judgment result is not at or near the boundary between the two urgency levels, the urgency level based on the provisional judgment result is used as the judgment result (step 105). .

As a result of the determination, if the emergency level determined by the provisional determination result is at or near the boundary between the two emergency levels, the steering output torque at the elapse of a set time (eg, 0.1 second) from the start of steering It is determined whether To decreases within a set time (for example, 0.4 seconds) thereafter (step 106). For this determination, the controller 50
When a set time (for example, 0.1 second) has elapsed since the start of steering,
From the steering input torque Ti read in chronological order, a steering output torque To at the time when a set time (for example, 0.1 seconds) has elapsed from the start of steering is obtained, and further, at a time when the set time (for example, 0.1 seconds) has elapsed from the start of the steering. Based on the change speed of the change acceleration of the steering output torque To, the steering output torque To at the time when a set time (for example, 0.4 seconds) has elapsed thereafter is calculated.

As a result of the judgment, if the steering output torque To does not decrease within the set time thereafter, the higher urgency level of the two urgency levels is determined as the judgment result (step 107), and the subsequent setting is performed. Steering output torque To within time
Decreases, the lower urgency level of the two urgency levels is determined as the determination result (step 108).

If an obstacle within a certain distance is not detected in Step 3 or if the steering direction is not the direction of the detected obstacle in Step 5, there is no possibility of collision with the obstacle, so there is no need to suppress steering. When the result of the determination of the steering urgency level in step 6 is “Urgent”, there is a possibility of collision with a forward obstacle, so that it is not necessary to suppress steering. In these cases, it is determined whether or not a steering output torque To exceeding the maximum absolute value P of the stored steering output torque To has been obtained, that is, whether or not to update the maximum value P (step 7). .

If the stored maximum value P of the absolute value of the steering output torque To is not updated in step 7, the change in the steering output torque To exceeding the maximum value Q of the absolute value of the change acceleration of the stored steering output torque To is changed. It is determined whether or not the acceleration is obtained, that is, whether or not to update the maximum value Q (step 8).

When the maximum value of the absolute value Q of the change acceleration of the steering output torque To stored in step 8 is not updated, the steering control current value calculated in step 2 is applied to the motor 13 to assist the steering. Perform (step 9). Thereafter, the process returns to step 1.

In the case where the maximum value P of the absolute value of the steering output torque To stored in the step 7 is updated, or the steering output torque To stored in the step 8 is updated.
When the maximum value Q of the absolute value of the change acceleration is updated, it corresponds to the updated maximum value P of the absolute value of the steering output torque To or the maximum value Q of the absolute value of the change acceleration of the steering output torque To. It is determined whether or not the intensity of the driver characteristic level exceeds the stored intensity of the driver characteristic level, that is, whether or not the driver characteristic level is updated (step 10).

When the driver characteristic level is updated in step 10, setting of the urgency level determination criterion,
The setting of the steering suppression strength and the set value Y to be compared with the value corresponding to the driver's resistance to the steering suppression are changed (step 11). "Urgent", "Quick",
The amount of change in the steering output torque To, which is a criterion for determining the boundary between the urgency levels of “normal” and “slow”, the change acceleration of the steering output torque To, and the torque added by the motor 13 for steering suppression, Each value of the set value Y is changed to a value associated with the updated driver characteristic level. After the setting change, the steering assist is performed in step 9 described above. If the driver characteristic level is not updated in step 10, the steering assist is directly performed in step 9.

If it is determined in step 4 that the vehicle is not in a steady running state, that is, if the vehicle is being steered,
From the sign of the steering output torque To, it is determined whether or not the steering direction is the direction of the detected obstacle, that is, whether or not there is a possibility of collision between the vehicle A and the obstacle (step 12).

In step 12, if the steering direction is the direction of the detected obstacle, that is, if there is a possibility of collision,
Based on the steering output torque To corresponding to the detected steering input torque Ti, it is determined whether or not the steering is the course correction steering as the steering state (step 13). For example, after the change due to one of the left and right steering operations within the set time of the steering output torque To exceeds the set value, the change due to the steering to the other left and right operation within the set time of the steering output torque To changes the set value. If it exceeds, it is determined that the steering is the course correction steering. Or,
The controller 50 integrates the steering output torque To at regular time intervals, and after a change of the integrated value due to steering to the left or right within a set time exceeds a set value, the integrated value of the integrated value is reduced. If the change due to the steering to the left or right within the set time exceeds the set value, it is determined that the steering is the course correction steering. This is based on the fact that it is possible to determine whether or not the purpose of the steering is the course correction steering based on the time change pattern of the steering output torque. For example, FIG. 16A illustrates a time change pattern of the steering output torque To when changing lanes, and the pattern is a substantially sinusoidal curve. In this case, the time point P1 at which the steering output torque To starts decreasing after steering to the left after the lane is changed to the right is the start time of the course correction steering. FIG. 16 (2) shows a time change pattern of the steering output torque To when passing through a curve. In this case, the time point P2 at which the steering output torque To starts decreasing by steering to the left after entering the right turn curve is the start time point of the course correction steering. In any case, after the change in the steering output torque for steering to one of the left and right occurs, the time points P1 and P2 at which the change in the steering output torque for steering to the other left or right occurs are the start of the course correction steering. It is time. The above determination is based on recognition of the start time of the course correction steering.

If it is determined in step 13 that the steering is not the course correction steering, that is, if there is a possibility of collision, the emergency level is determined in step 6 described above.

If the result of the determination of the steering urgency level in step 6 is not the highest "urgent", it is determined whether the steering purpose is to enter a curve or change lanes as the steering state (step 14).

FIG. 9 is a flowchart showing a procedure for determining whether the steering purpose is to enter a curve or to change lanes.

First, it is determined whether or not the determination result of the steering urgency level in step 6 is equal to or less than the boundary between "normal" and "slow", that is, the change acceleration of the steering output torque To is equal to or less than the substantially zero threshold value. Is determined (Step 2
01).

If the change acceleration of the steering output torque To is equal to or less than the threshold value, a set time thereafter (for example, 0.1 second)
The change acceleration of the steering output torque To is calculated based on the change speed of the change acceleration of the steering output torque To when a set time (for example, 0.1 second) elapses from the start of the steering, and whether the change acceleration thereafter decreases or not. (Step 20)
2) If it decreases, it is determined that the purpose of steering is lane change (step 203), and if it does not decrease, it is determined that the purpose of steering is to enter a curve (step 204).

If the change acceleration of the steering output torque To is not equal to or smaller than the threshold value, it is determined whether or not the change acceleration decreases within a subsequent set time (for example, 0.1 second) (step 205). If it decreases, it is determined that the purpose of the steering is to enter the curve. If it does not decrease, it is determined that the purpose of the steering is to change lanes.

If it is determined in step 14 that the purpose of the steering is not to enter the curve but to change lanes, the steering is suppressed (step 15). This steering suppression is performed by causing the motor 13 to generate an additional torque having the opposite sign to the steering input torque Ti. The absolute value of the additional torque for suppressing the steering changes according to the absolute value of the steering input torque Ti, and changes according to the strength of the driver characteristic level. For example, in the case where the driver characteristic level is the strongest, the additional torque that balances with the steering input torque Ti is determined so that the steering output torque To becomes zero. The torque ratio is reduced. As a result, the degree of steering suppression increases as the steering input torque Ti increases and the driver characteristic level increases, and conversely, decreases as the steering input torque Ti decreases and the driver characteristic level decreases. During steering suppression,
The voice alarm 52 alerts the driver of the danger of collision by voice.

Next, it is determined whether or not the driver has resistance to the steering suppression (step 16). Since the absolute value of the additional torque for steering suppression changes according to the absolute value of the steering input torque Ti and the driver characteristic level, the presence or absence of the driver's resistance is determined from the driver characteristic level, the steering input torque Ti and the additional torque. You can judge. For example, when the driver characteristic level is the strongest, there is no driver resistance if the steering input torque Ti and the additional torque are balanced, and there is a driver resistance if the steering input torque Ti is large.

If there is no driver's resistance to the steering suppression in step 16, the process returns to step 1 without canceling the steering suppression.

In step 16, if there is a driver's resistance to the steering suppression, a value corresponding to the time integrated value of the driver's resistance from the start of the steering suppression is determined as a value corresponding to the degree of the driver's resistance to the steering suppression. It is determined whether the value is equal to or greater than the set value Y (step 17). In the present embodiment, a time integrated value of the steering input torque Ti from the start of steering suppression is calculated as a value corresponding to the time integrated value of the resistance of the driver. The set value Y
Is set according to the driver characteristic level as described above.

In step 17, the steering input torque Ti
If the time integration value from the start of the steering suppression is less than the set value Y, the process returns to step 1 without canceling the steering suppression.

In step 17, the steering input torque Ti
If the time integrated value from the start of the steering suppression is equal to or more than the set value Y, the steering suppression and the warning are canceled (step 18). FIG.
As shown in (1) of (1), the steering input torque Ti applied by the driver while resisting the steering suppression has the opposite sign to the additional torque Ta for steering suppression, and changes according to the additional torque Ta. Therefore, as shown in FIG. 11 (2), the time integral value of the steering input torque Ti from the start of steering suppression gradually increases. This necessitates steering during the steering suppression, and when the driver resists the steering suppression, the steering suppression can be released. In this case, since the steering suppression is released when the time integral value of the steering input torque Ti from the start of the steering suppression is equal to or more than the set value Y, the time until the driver releases the steering suppression as the resistance to the steering suppression increases. , The steering suppression can be released earlier as the urgency of the steering suppression release is higher.
It is possible to cope with a change in the urgency level during steering suppression. For example, if an obstacle suddenly appears ahead while performing steering suppression because there is another vehicle behind the host vehicle, the driver increases the steering input torque Ti against the steering suppression. Steering suppression can be released in a short time, and an obstacle ahead can be avoided. Also,
When the degree of urgency of the steering decreases during the steering suppression, for example, when the obstacle in front disappears, the driver decreases the steering input torque Ti. In this case, the time until the cancellation of the steering suppression is increased, and the accuracy of avoiding a collision with a lateral or rear obstacle can be improved. As shown in (3) of FIG. 11, the set value Y is changed according to the vehicle speed detected by the vehicle speed detection sensor 51. That is, the set value Y
Are made smaller as the speed increases. Thus, the steering suppression can be released at an appropriate timing according to the vehicle speed. Since the set value Y changes according to the level of the driver characteristic level as described above, the steering suppression time can be changed according to the characteristics of the driver. That is, for a driver with relatively strong power or a driver who performs steering relatively sharply for rough driving, the set value Y is increased, while a driver with relatively weak power or steering is relatively For a driver who performs gently, the set value Y can be reduced, and the steering suppression can be appropriately released in accordance with the characteristics of the driver.

When the steering suppression is released, it is determined whether or not a steering input torque Ti exceeding the maximum absolute value R of the stored steering input torque Ti is obtained, that is, whether or not the maximum value R is updated. Is determined (step 19).

When the maximum value of the absolute value R of the steering input torque Ti stored in step 19 is not updated, the steering assist is performed in step 9. When the maximum value R of the absolute value of the steering input torque Ti stored in step 19 is updated, in step 10, the intensity of the driver characteristic level corresponding to the updated maximum value R of the absolute value of the steering input torque Ti is changed. It is determined whether or not the strength of the stored driver characteristic level is exceeded, that is, whether or not to update the driver characteristic level. If the driver characteristic level is to be updated, the setting of the criterion of the urgency level, the setting of the steering suppression intensity, and the setting of the set value Y are changed in step 11, and if not updated, the steering assist is performed in step 9.

If it is determined in step 12 that the steering direction is not the direction of the detected obstacle, or if it is determined in step 13 that the steering is path correction steering, that is, if there is no possibility of collision, the absolute value of the stored steering output torque To is calculated. It is determined whether or not the steering output torque To exceeding the maximum value P is obtained, that is, whether or not the maximum value P is updated (step 20).

If the maximum value P of the absolute value of the steering output torque To stored in step 20 is not updated, the steering assist is performed in step 9. When the absolute value P of the absolute value of the steering output torque To stored in step 20 is updated, in step 10, the intensity of the driver characteristic level corresponding to the updated absolute value P of the absolute value of the steering output torque To is changed. It is determined whether or not the strength of the stored driver characteristic level is exceeded, that is, whether or not to update the driver characteristic level. If the driver characteristic level is to be updated, the setting of the criterion of the urgency level, the setting of the steering suppression intensity, and the setting of the set value Y are changed in step 11, and if not updated, the steering assist is performed in step 9.

FIG. 12 shows a state in which the other vehicle C follows the right rear of the own vehicle A having the above-described configuration and is traveling rightward in the figure. In this state, steering for changing lanes was performed at an emergency level of "quick" or less at a position where the other vehicle C can be detected by the sensor. In this case, the additional torque Ta corresponding to the steering input torque Ti is generated as the steering suppression torque, and the steering output torque To does not change unless the resistance corresponding value becomes equal to or greater than the set value Y. After a while
The distance between the host vehicle A and the other vehicle C was increased, and steering for changing lanes was performed at an emergency level of "quick" or less at a position where the other vehicle C could not be detected by the sensor.
In this case, the additional torque Ta corresponding to the steering input torque Ti is generated as the steering assist torque, and the steering is not suppressed.

FIG. 13 (1) shows a position where the other vehicle C to the right of the host vehicle A having the above configuration and traveling rightward in the figure is detected by a sensor, and the obstacle B in front is avoided. Therefore, a state in which steering for changing lanes is performed at the “emergency” level is shown. In this case, the additional torque Ta corresponding to the steering input torque Ti was generated as the steering assist torque, and the steering was not suppressed. In this case, when the steering is performed under the “quick” or less, the steering is suppressed, and the resistance corresponding value is set to the set value Y.
Then, the steering suppression is released. In this case, when the conventional steering suppression control is performed, as shown in (2) of FIG. 13, an additional torque Ta corresponding to the steering input torque Ti is generated as the steering suppression torque, and the steering output torque To does not change. The vehicle A and the obstacle B may collide.

FIG. 14A shows a state in which steering for entering a curve is performed at a position where a sensor can detect another vehicle C inside the own vehicle A having the above configuration. In this case, the additional torque Ta corresponding to the steering input torque Ti was generated as the steering assist torque, and the steering was not suppressed. If conventional steering suppression control is performed in this case, as shown in (2) of FIG. 14, an additional torque Ta corresponding to the steering input torque Ti is generated as the steering suppression torque, and the steering output torque To does not change. Therefore, the vehicle A cannot enter the curve.

FIG. 15 (1) shows a state in which the own vehicle A having the above-mentioned structure overtakes another vehicle C ahead and performs a course correction steering at a position where the vehicle C can be detected by a sensor. In this case, an additional torque Ta corresponding to the steering input torque Ti is generated as a steering assist torque,
No steering restraint was made. If the conventional steering suppression control is performed in this case, as shown in FIG.
At the beginning of the course correction steering, an additional torque Ta corresponding to the steering input torque Ti is generated as the steering suppression torque, the steering output torque To does not change, and the steering assist is not performed until the own vehicle A and the other vehicle C separate. Therefore, following the lane after the change is delayed.

According to the above-described embodiment, the additional torque Ta generated as the steering suppression torque is determined such that the steering output torque To has a predetermined value. That is, steering suppression control is performed based on the steering output torque To. As a result, the steering suppression can be controlled based on the behavior change of the vehicle A. Since the change in the behavior of the vehicle corresponds to the sum of the steering input torque Ti and the additional torque Ta, the change in the steering input torque Ti is offset by the change in the additional torque. Therefore, the steering output torque T
The influence of disturbance due to unevenness of the road surface and the like and the influence of electric noise on the torque sensor 3 are smaller than those on the steering input torque Ti. Further, when performing control to change the steering assist torque according to the vehicle speed, the difference in the rise characteristics of the steering input torque Ti according to the vehicle speed, and the rise characteristics of the steering input torque Ti according to the assist gain and the phase compensation gain. Differences are also offset by changes in the additional torque. Therefore, by controlling the steering suppression based on the steering output torque To, the presence or absence of steering can be accurately determined, and it is possible to prevent the proper steering suppression from being hindered. Further, since the steering output torque To is advanced in phase compared to other characteristics corresponding to the change in the behavior of the own vehicle A, for example, the steering angle and the yaw rate, the change in the behavior of the own vehicle A can be detected early, The response of the control system can be improved.
Further, a value detected for assisting steering is determined by a steering output torque T.
Since it can be detected as a value corresponding to o, there is no need to provide a dedicated sensor for detecting a change in the behavior of the vehicle, for example, an axial force sensor that causes the rack 7 to act on the steering wheel 8, and the configuration is complicated. The cost can be reduced without any cost reduction.

For a driver with relatively strong power or a driver who performs steering relatively sharply because of rough driving, the strength of steering suppression is increased. On the other hand, a driver with relatively weak power or steering is relatively weak. The strength of the steering suppression can be weakened for the driver who performs the operation relatively slowly, and the steering suppression having an appropriate strength according to the characteristics of the driver can be performed. Further, by changing the amount of change of the steering output torque To and the setting of the change acceleration of the steering output torque To, which are the criteria for judging the urgency level, according to the characteristics of the driver, the urgency level can be changed. It can be appropriately determined according to. In other words, for a driver with relatively strong power or a driver who steers relatively sharply for rough driving, the criteria for judging the boundary of the urgency level is set high, while a driver with relatively weak power or steering is used. A driver who performs relatively gently can lower the criterion for determining the boundary of the urgency level.

In the above embodiment, the maximum value of the absolute value of the steering output torque To during the actual operation of the vehicle, the maximum value of the absolute value of the change acceleration of the steering output torque To, and The maximum value of the absolute value of the steering input torque Ti is determined, and the determination value of the urgency level, the setting of the steering suppression intensity, and the value corresponding to the driver's resistance to the steering suppression are compared with the determined value. Although the setting of the set value Y was changed, a value corresponding to the strength of the driver characteristic level in a stopped state was obtained before starting actual vehicle driving, and an urgency level was determined in accordance with the obtained value. May be changed, the setting of the steering suppression strength, and the setting of the set value Y may be changed. That is, as shown in the flowchart of the first modification of FIG. 17, first, a check mode display is performed on a liquid crystal display device or the like mounted on a vehicle (step 301). This check mode display is a display of a text or the like for causing the driver to recognize that the current mode is a mode for checking the driver characteristic level, and for example, a display such as “the current driver characteristic level check mode” is performed. Next, an input instruction is performed (step 302). This input instruction
This is for instructing the driver of a steering input necessary for detecting the strength of the driver characteristic level. For example, a display such as "Please rotate the steering wheel as quickly as possible with as much force as possible" is displayed. Next, the absolute value of the steering input torque input according to the instruction is read as a value corresponding to the strength of the driver characteristic level (step 303), and the controller 5
Store to 0. Next, the setting of the judgment level of the urgency level, the setting of the steering suppression strength, and the setting of the set value Y are changed according to the stored values (step 304).

Further, a volume knob capable of changing a value corresponding to the strength of the driver characteristic level is provided, and the setting of the strength of the driver characteristic level can be changed by the driver himself / herself by operating the knob. The setting of the criterion for the degree level, the setting of the steering suppression strength, and the setting of the set value Y may be changeable.

FIGS. 18 and 19 show the setting of the criterion for determining the urgency level, the setting of the steering suppression strength, the set value Y, and the set value Tmax to be described later before the actual vehicle operation is started. The control procedure when changing the setting will be described.
In the control procedure of the first modification, step 401
To 406 are the same as steps 1 to 6 in the control procedure shown in FIGS.
411 is Step 1 in the control procedure of the above embodiment.
Steps 413, 414, 415, equal to 2-16
Are the steps 17 and 1 in the control procedure of the above embodiment.
Steps 412 and 411 are the same as steps 8 and 9 and do not include steps 7, 8, 10, 11, and 19 in the control procedure of the above embodiment.
And 413. In that step 412,
If it is determined in step 411 that there is a driver's resistance, the driver's steering input torque T is set as a value corresponding to the degree of the driver's resistance to steering suppression.
i is determined, and it is determined whether the value Ti is equal to or greater than a set value Tmax. In the present embodiment, the steering input torque Ti is obtained as a value corresponding to the resistance of the driver. If the steering input torque Ti is smaller than the predetermined set value Tmax in step 412, the process proceeds to step 413. If the steering input torque Ti is equal to or greater than the set value Tmax, the process proceeds to step 414. Others are the same as the above embodiment. According to this modification, the same effect as the above embodiment can be obtained. Further, in an emergency where it is highly necessary to cancel the steering suppression, the driver can quickly cancel the steering suppression by applying a large resistance force. The value of the set value Tmax compared with the steering input torque Ti in step 412 in this modified example is also
13, the setting is changed according to the driver characteristic level.

In the first modification, step 413 is eliminated, and if the steering input torque Ti is smaller than the set value Tmax in step 412, step 40 is executed.
You may make it go to 1.

FIG. 20 shows a flowchart of the second modification, in which step 9 of the above embodiment is replaced with steps 9a and 9a.
b, 9c. That is, in the above embodiment, when performing the steering assist, the control current value calculated in step 2 is applied to the motor 13.
On the other hand, in the second modification, when performing the steering assist, first, the urgency level of the steering is determined (step 9).
a). The determination of the urgency level can be performed according to the procedure shown in the flowchart of FIG. 8 as in the above embodiment.

If the determination result of the steering urgency level in step 9a is "quick" or more, that is, "urgent" or "quick", the control current value calculated in step 2 is reduced (step 9b). The reduction amount is determined so that the vehicle behavior does not become unstable due to steering, and can be obtained by an experiment. The reduction amount may be increased as the degree of urgency determined is higher, or may be a constant amount regardless of the degree of urgency. The urgency level at which the steering assist force is reduced can be set arbitrarily, and the control current value may be reduced only when the urgency level of the steering is “urgent” or higher.

The steering assist is performed by applying the reduced drive current value to the motor 13. Step 9a
If the result of the determination of the urgency level of the steering is less than "quick", that is, "normal" or "slow", the steering is performed by applying the drive control current value calculated in step 2 to the motor 13 without reducing it. Assistance is performed (step 9c). Others are the same as the first embodiment.

According to the second modification, the steering assist force can be reduced when the vehicle is steered rapidly. Thereby, it is possible to prevent the vehicle behavior from becoming unstable when the vehicle is steered suddenly in the opposite direction after the steering is suppressed by steering in the direction in which a collision is likely to occur. . Further, even when steering is performed very rapidly in order to avoid an obstacle in front of the vehicle, it is possible to prevent the steering from being performed more rapidly than necessary and to stabilize the vehicle behavior. In addition,
Also in the first modification, the steering urgency level is determined when performing the steering assist, and the control current value of the motor 13 is reduced when the urgency level is equal to or higher than the setting. Similar effects can be obtained.

FIG. 21 shows a flowchart of the third modification, in which step 17 of the above embodiment is replaced with step 17 '. That is, in the above-described embodiment, the value corresponding to the time integral value of the steering input torque Ti from the start of the steering suppression is obtained as the driver resistance value for the steering suppression. The steering input torque Ti corresponding to the resistance force is obtained, and the steering input torque Ti is detected by the torque sensor 3 as a detection limit value Ty.
Is determined. The steering input torque Ti
Reaches the detection limit value Ty of the torque sensor 3, the steering suppression is released. The detection limit value Ty is obtained in advance and stored in the controller 50. Others are the same as the first embodiment.

According to the third modification, the steering input torque Ti corresponding to the driver's resistance to steering suppression is set.
However, since the steering suppression can be released by reaching the detection limit value of the torque sensor 3, when the necessity of the steering suddenly increases during the steering suppression, the steering inhibition is promptly released by increasing the steering input torque Ti. However, a delay in steering can be prevented. Also, since the driver's intention to release the steering suppression can be promptly reflected, it is possible to prevent the steering wheel from being returned excessively in the direction opposite to the direction in which a collision may occur. Note that the set value Tmax in step 412 of the first modified example may be the detection limit value Ty of the torque sensor 3 as in the second modified example.

[0096] The present invention is not limited to the above-described embodiment and modifications. For example, the value corresponding to the degree of the driver's resistance to the steering suppression is not limited to the steering input torque Ti or the time integrated value of the steering input torque Ti from the start of the steering suppression. May correspond to the steering input torque Ti, a value obtained by reversing the sign of the drive control current value of the motor 13 or a time integrated value of the value may be used.

In the above embodiment, the steering input torque is detected as a value corresponding to the steering output torque. Alternatively, the steering input torque and the drive control current value of the motor 13 may be detected in time series. Good. In this case, FIG.
Instead of the relationship between the steering input torque and the steering output torque as shown in the above, a predetermined relationship between the drive control current value of the motor 13 and the steering input torque is stored in the controller 50. When performing steering assist, the motor 13 is driven by a drive current value associated with the detected steering input torque by the stored relationship. Accordingly, the detected steering input torque and the drive control current value are associated with the steering output torque.

Further, the steering urgency level is not limited to four levels, and may be three or less levels or five or more levels. Further, the steering urgency level may be classified according to the lateral acceleration acting on the vehicle at the time of steering.

[0099] The method of steering assist and steering suppression is not particularly limited. For example, a steering assist force or a steering suppression force may be generated by hydraulic pressure. Further, the magnitude of the steering assist force or the steering suppression force is not particularly limited as long as appropriate steering assist or steering suppression can be performed.

[0100]

According to the present invention, the urgency of steering suppression release reflecting the driver's intention is accurately determined with a simple structure, and the steering suppression is released at a timing according to the urgency. It is possible to provide a vehicle steering device capable of appropriately avoiding danger.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the time required to move 1 m when changing lanes and the amount of change in steering output torque during a set time.

FIG. 2 is a diagram showing the relationship between the time required to move 1 m when changing lanes and the change acceleration of the steering output torque at the elapse of a set time.

FIG. 3 shows the amount of change in steering output torque during a set time;
Diagram showing the relationship between the change in the steering output torque and the acceleration after the set time has elapsed

FIG. 4 is a diagram illustrating the configuration of a vehicle according to an embodiment of the present invention.

FIG. 5 is a flowchart showing a control procedure of the steering device according to the embodiment of the present invention.

FIG. 6 is a flowchart showing a control procedure of the steering device according to the embodiment of the present invention.

FIG. 7 is a flowchart showing a control procedure of the steering device according to the embodiment of the present invention.

FIG. 8 is a flowchart showing a steering state determination procedure according to the embodiment of the present invention.

FIG. 9 is a flowchart showing a steering state determination procedure according to the embodiment of the present invention.

FIG. 10 is a diagram showing a relationship between a steering input torque and a steering output torque.

FIGS. 11 (1) to (3) are explanatory diagrams of a steering suppressing action of the embodiment of the present invention.

FIG. 12 is an operation explanatory diagram when the steering state is determined according to the embodiment of the present invention.

FIG. 13A is a diagram illustrating an operation when a steering state determination is performed to determine whether or not an emergency level is set according to the embodiment of the present invention;
(2) is an operation explanatory diagram in the case where the steering state determination of whether or not it is the urgency level is not performed;

FIG. 14 (1) is an explanatory diagram of an operation when a steering state determination of whether or not to enter a curve according to the embodiment of the present invention is performed, and (2).
Is an operation explanatory diagram in the case where the steering state determination of whether or not to enter a curve is not performed;

FIG. 15 (1) is an operation explanatory diagram in a case where a steering state determination of whether or not a course correction steering according to the embodiment of the present invention is performed,
(2) is an explanatory diagram of the operation when the steering state determination of whether or not the steering is the course correction steering is not performed.

16A is a diagram showing a time change pattern of steering output torque when changing lanes, and FIG. 16B is a diagram showing a time change pattern of steering output torque when passing a curve.

FIG. 17 is a flowchart showing a procedure for detecting a driver characteristic level according to the first modification of the present invention;

FIG. 18 is a flowchart showing a control procedure according to a first modification of the present invention.

FIG. 19 is a flowchart showing a control procedure according to a first modification of the present invention.

FIG. 20 is a flowchart showing a control procedure according to a second modification of the present invention.

FIG. 21 is a flowchart showing a control procedure according to a third modification of the present invention.

[Explanation of symbols]

 Reference Signs List 1 power steering device 3 torque sensor 13 motor 50 controller 53, 54, 55, 56 obstacle detection sensor A vehicle

Continued on the front page (51) Int.Cl. ⁶ Identification code FI B62D 119: 00 137: 00

Claims (6)

[Claims] In a vehicle steering apparatus capable of suppressing steering based on a possibility of collision with an obstacle, a resistance correspondence value corresponding to a degree of a driver's resistance to the steering suppression is determined, and the resistance correspondence value is set. A steering device for a vehicle, comprising: means for determining whether or not the value is equal to or greater than a value, and canceling the steering suppression when the resistance corresponding value is equal to or greater than a set value. 2. The vehicle steering system according to claim 1, wherein a value corresponding to a time integrated value of the driver's resistance from the start of the steering suppression is obtained as the driver's resistance corresponding to the steering suppression. 3. The vehicle steering system according to claim 1, wherein a value corresponding to the driver's resistance is obtained as the driver's resistance corresponding to the steering suppression. 4. The vehicle steering system according to claim 1, further comprising means for changing the set value according to characteristics of the driver. 5. The vehicle steering system according to claim 1, further comprising means for changing the set value according to the vehicle speed. 6. A steering assisting means, comprising: means for performing steering assistance; and means for determining a steering urgency level, wherein the steering assisting force can be reduced when the steering urgency level is equal to or higher than a set value. 6. The steering apparatus for a vehicle according to any one of the items 5.