JPH09301207A - Steering device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a steering suppression according to the characteristic of a driver and emergency level by providing a means capable of changing the setting of strength of steering suppression according to the characteristic of the driver. SOLUTION: A controller 50 stores a predetermined corresponding relation between change quantity of steering output torque and emergency level of steering within a set time from steering start, and stores a predetermined corresponding relation between the change acceleration of steering output torque and the emergency level of steering. The controller 50 also stores the maximum absolute value of steering output torque, the maximum absolute value of change acceleration of steering output torque, and the maximum absolute value of steering input torque. The controller 50 judges the emergency level of steering and the purpose of steering according to a stored control program, thereby performing a steering assisting control and a steering suppression control.

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. In the present specification, the change acceleration of the steering output torque is 2 times the steering output torque time.
The term "differential value" refers to the change speed of the change acceleration of the steering output torque, and the differential value of the change acceleration of the steering output torque with respect to time.

[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.

Conventionally, the strength of the steering suppression is uniquely set without considering the characteristics of the driver, and for example, it has been set to a size commensurate with the size of the steering input torque.

However, if the strength of the steering suppression is set without considering the characteristics of the driver, it is sufficient for a driver who has a relatively strong force and a driver who steers comparatively rapidly for rough driving. There is a problem that steering cannot be suppressed, or conversely, the strength of the steering is excessive for a driver who has a relatively weak force or a driver who performs a relatively gentle steering.

Further, in order to suppress such steering,
The presence or absence of steering is detected based on the steering input torque. Conventionally, the presence or absence of steering has been determined by whether or not the amount of change in steering input torque within a set time from the start of steering is larger than the set amount. The set time needs to be as short as possible in order to perform the steering suppression quickly.

However, the urgent level of steering cannot be accurately determined only from the amount of change in the steering input torque within a short time after the start of steering. For example, when avoiding a front obstacle that is more dangerous than a side or rear side obstacle, the urgency level of steering becomes very high.

Therefore, as shown in (2) of FIG.
Although the obstacle B exists in front of the host vehicle A, steering is suppressed because the other vehicle C is on the rear side,
There is a possibility that the obstacle B ahead cannot be avoided. In addition,
13 (2) shows a state where the own vehicle A and the other vehicle C are traveling to the right in the figure.

Therefore, a sensor for detecting a front obstacle as well as a sensor for detecting a side or rear side obstacle is provided, and detection of a side obstacle immediately after detection of a front obstacle is ignored. It is possible to control. However, in this case, a sensor for detecting a forward obstacle is indispensable, which is expensive.

Further, a method has been proposed in which the degree of danger is obtained from changes 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 according to 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.

Further, the prior art has not dealt with any change in the urgency level during steering suppression, for example, a situation in which a front obstacle suddenly appears.

In view of the above-mentioned prior art, the present invention can set the strength of steering suppression according to the characteristics of the driver, and can appropriately perform the steering suppression by appropriately determining the urgency level of steering according to the characteristics of the driver. An object of the present invention is to provide a steering device for a vehicle.

[0012]

According to the present invention, in a steering apparatus for a vehicle capable of suppressing steering based on the possibility of collision with an obstacle, the setting of the strength of the steering suppression is changed according to the characteristics of the driver. It is characterized by comprising possible means.
As a result, the strength of the steering suppression is increased for a driver who has a comparatively strong force or a driver who steers comparatively rapidly for rough driving, while a driver with a comparatively weak force and a driver who steer comparatively The degree of steering suppression can be weakened for a driver who performs gently, and the steering can be suppressed with an appropriate strength according to the characteristics of the driver.

Further, according to the present invention, in a vehicle steering system capable of suppressing steering based on the possibility of collision with an obstacle, means for detecting a value corresponding to a steering output torque in time series,
The steering state determination means for determining the urgency level of steering based on the detected value, the means for setting the steering suppression time according to the urgency level, and the steering output torque serving as the determination reference for the urgency level It is characterized by comprising means for changing the setting of the corresponding value according to the characteristics of the driver. As a result, by setting the steering suppression time according to the urgency level of steering based on the steering output torque,
The front obstacle can be avoided without providing a detection sensor for the front obstacle. This is because the higher the urgency level of steering is, the higher the necessity of avoiding a front obstacle is. Therefore, by shortening the steering suppression time, the risk of collision with a front obstacle can be reduced. On the other hand, the lower the urgency level of steering, the lower the necessity of avoiding a front obstacle, and even if the steering suppression time is lengthened, there is no risk of collision with a front obstacle. In addition, by increasing the steering suppression time as the urgency level of steering is lower, it is possible to improve the accuracy of avoiding a collision with a side or rear side obstacle. By changing the setting of the value corresponding to the steering output torque, which is the criterion for determining the urgency level, according to the characteristics of the driver, the urgency level can be appropriately determined according to the characteristics of the driver. 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 present invention, means for detecting the steering input torque in time series is provided, and the set length of the steering suppression time corresponds to the magnitude of the steering input torque during the steering suppression and the characteristics of the driver. Is preferred. This allows
It is possible to cope with a change in the urgency level during steering suppression. That is, when the urgency of steering increases during steering suppression, the driver increases the steering input torque against steering suppression, so the steering input torque during steering suppression is greater than when the urgency level does not change. To increase. Further, the degree of increase in the steering input torque varies depending on the characteristics of the driver. Therefore, if the urgency level increases during the steering suppression, the steering suppression can be released in a short time to avoid the front obstacle. on the other hand,
When the urgency of steering decreases during steering suppression, for example, when the front obstacle disappears, the driver decreases the steering input torque.Therefore, the steering input torque during the steering suppression changes the urgency level. It decreases compared to the case without. In addition, the degree of decrease in the steering input torque varies depending on the characteristics of the driver. Therefore, when the urgency level decreases during steering suppression, the accuracy of avoiding a collision with a side or rear side obstacle can be improved by lengthening the time until cancellation of steering suppression. In addition, the increase or decrease of the steering input torque when the urgency level of the steering changes while the steering is suppressed varies depending on the characteristics of the driver. For drivers who do this, the criterion for determining the boundary of the urgency level is set high, while for drivers who have a relatively weak force or drivers who perform a relatively gentle steering,
By lowering the criterion of the urgency level boundary,
The change in the urgency level can be appropriately determined according to the driver characteristic, and the steering suppression time can be appropriately set according to the driver characteristic.

The steering state determination means of the present invention is a means for storing a predetermined correspondence between the amount of change in the steering output torque within a set time from the start of steering and the urgency level of steering, and when the set time elapses. Means for storing a predetermined correspondence between the change acceleration of the steering output torque and the urgency level thereof, and the urgency level corresponding to the change amount of the steering output torque corresponding to the detected value within the set time. And a means for determining whether or not the steering output torque corresponding to the detected value and the urgency level corresponding to the change acceleration at the time when the set time has elapsed coincide with each other. It is preferable to determine the urgency level.

As a result, if the result of the determination is that the two urgency levels are the same and the two urgency levels are not at or near the boundary between the two urgency levels, the urgency level can be used as the determination result. Further, as a result of the determination, if the two urgency levels do not match and the urgency level corresponding to the change acceleration is not at or near the boundary between the two urgency levels, the urgency level corresponding to the change acceleration is determined. The level can be used as the determination result. Further, as a result of the determination, when the urgency level corresponding to the change acceleration is at or near the boundary between the two urgency levels, the steering output torque at the time when the set time has elapsed from the start of steering is within the subsequent set time. If the steering output torque is increased within the subsequent set time, a means for determining whether to increase or decrease to
The higher urgency level of the two urgency levels can be used as the determination result, and the lower urgency level of the two urgency levels can be used as the determination result if it decreases within the set time thereafter. it can. Further, means for determining whether or not the change acceleration of the steering output torque corresponding to the detected value when the set time has elapsed is less than or equal to a preset threshold value, and the change acceleration of the steering output torque is less than or equal to the threshold value. In some cases, the means for determining whether or not the change acceleration decreases within the subsequent set time, and if the change acceleration of the steering output torque is not less than or equal to the threshold value, the change acceleration is within the subsequent set time. When the change acceleration of the steering output torque is less than or equal to the threshold value, the purpose of the steering is to change to the lane if the change acceleration of the steering output torque is less than or equal to a threshold value. Determined to be a change,
If it does not decrease, it is determined that the purpose of steering is to enter the curve, and if the change acceleration of the steering output torque is not less than the threshold value, if the change acceleration decreases within the subsequent set time, the purpose of steering is to enter the curve. If it is not decreased, it can be determined that the purpose of steering is lane change.

The determination of the emergency level by the steering state determination means is based on the following knowledge.

First, in the case of changing lanes, the relationship between the urgency level of steering and the amount of change in steering output torque within a set time from the start of steering is determined by an experiment using a vehicle equipped with an electric power steering device. I asked.
FIG. 1 shows the results of the experiment.

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 shows the amount of change (N · m) in the steering output torque during the 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 experimental result data is plotted by "●" and "Δ". The data a to v indicated by "●" indicate the 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 the standard steering is performed when the lane is changed, the amount of change in the steering output torque within the 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 with the change acceleration of the steering output torque after a lapse of seconds) was obtained by an experiment using a vehicle equipped with an 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 indicates a vehicle speed of 50 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 shown as “●” as the result of the standard steering 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 changing lanes, the urgency level of the steering and the change acceleration of the steering output torque correspond to each other. Can be confirmed. 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 are classified near the "quick" boundary. 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, regarding the data k, o, n, ε, r, t, u, v whose urgent 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 seconds) has elapsed from the start of steering and at the time when the set time (0.4 seconds) has 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 making a curve entry,
The relationship between the change amount of the steering output torque within the set time from the start of steering and the change acceleration of the steering output torque at the time when the set time has elapsed 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 indicates a vehicle speed of 50 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 when entering the curve are plotted by "●" 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.

Further, in FIG. 3, when the lane is changed, the relationship between the amount of change in the steering output torque within the set time from the start of steering and the change acceleration of the steering output torque at the time when the set time elapses is also shown. Showed. As the data when the lane change is made, "○" indicates that the emergency level of steering is classified as "normal", and "△" indicates that it is classified at the boundary between "normal" and "slow". ".

From the standard steering data shown in FIG. 3, it can be confirmed that the standard acceleration of the steering output torque is substantially zero or less when the standard steering is performed when entering a curve. 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 curve entering data by the standard steering indicates that the steering level is a steering for changing lanes and the urgency level is "normal" based on the change amount of the steering output torque and the change acceleration of the steering output torque. It is smaller than the boundary with "slow", and its change acceleration cannot be distinguished from data whose threshold value is substantially zero or less. 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, from the irregular steering data shown in FIG. 3, when the irregular steering is performed at the time of entering a curve, that is, when the steering wheel is intentionally sharply cut at the beginning of the steering, the steering is performed. It can be confirmed that the change acceleration of the output torque becomes larger than the threshold value of substantially zero.

The curve entry data due to the irregular steering is based on the amount of change in the steering output torque and the acceleration of the change in the steering output torque. However, it cannot be distinguished from a change acceleration exceeding a threshold value of substantially zero. 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 change amount of the steering output torque within the set time from the start of steering, the change acceleration of the steering output torque after the set time has elapsed, and the subsequent setting of the steering output torque after the set time has elapsed from the start of steering. Based on the increase / decrease in time and the increase / decrease in the change acceleration of the steering output torque in the subsequent set time, the urgency level of steering can be determined, and further the purpose of steering can be determined.

In the present invention, the characteristics of the driver include the maximum absolute value of the steering output torque, the maximum absolute value of the change acceleration of the steering output torque, and the maximum absolute value of the steering input torque. It is preferable to include means for determining the strength of the driver characteristic level corresponding to at least one. As a result, the amount of change in the steering output torque and the acceleration of the change in the steering output torque, which are the criteria for determining the boundary of the urgency level, are increased by a driver with a relatively strong force or a driver who steers relatively rapidly. However, it is lowered for drivers who are relatively weak and those who perform steering relatively gently.

[0040]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The rack and pinion type electric power steering device 1 shown in FIG. 4 includes an input shaft 2 connected to a steering wheel H of a vehicle A, and an output shaft 4 connected to the input shaft 2 via a torque sensor 3. There is.
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. The 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. From the relationship between the steering input torque and the steering output torque stored in the controller 50 described later, the steering input torque is associated with the steering output torque.

The torque sensor 3 is connected to a controller 50 composed of 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 a predetermined correspondence relationship between the amount of change in the steering output torque within a set time from the start of steering and the urgency level of steering, and the changed acceleration and the urgency of steering. A predetermined correspondence with the level is 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 has a maximum absolute value of the steering output torque To, a maximum absolute value of the changing acceleration of the steering output torque To, and a steering input torque Ti as values corresponding to the characteristics of the driver. The maximum absolute value of 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 value between the upper limit value P1 and the 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. Between the upper limit value Q1 and the lower limit value Q2 of the maximum absolute value Q, and between the upper limit value R1 and the lower limit value R2 of the maximum absolute value R of the steering input torque Ti. The values of and 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.

The strength of the driver characteristic level corresponds to the urgent level determination criterion and the steering suppression strength. In other words, the stronger the driver characteristic level, the higher the urgency level determination criterion, the greater the steering suppression strength, and the driver with a relatively strong force or the driver who steers relatively rapidly. The amount of change in steering output torque and the acceleration of change in steering output torque, which are the criteria for determining the boundary of the urgency level of ",""normal," and "slow," are increased, and are added by the motor 13 to suppress steering. Torque is increased. On the other hand, in the case of a driver having a comparatively weak force or a driver who performs steering relatively gently, the amount of change in the steering output torque and the acceleration of the change in the steering output torque, which are the determination criteria, are lowered, and the additional torque by the motor 13 is reduced. Made smaller. Correspondence between the amount of change in steering output torque that is the criterion for the boundary of the urgency level and the driver characteristic level, and the correspondence between the change in steering output torque that is the criterion for determining the boundary of the urgency level and the driver characteristic level The relationship and the corresponding relationship between the steering suppression strength and the driver characteristic level are stored in the controller 50. Each correspondence is
It may be obtained by experiments with drivers having different characteristics.

[0048]

[Table 1]

The controller 50 determines the urgency level of steering and the purpose of steering in accordance with the stored control program, thereby performing the following steering assist control and steering suppression control. 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, the 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, the drive control current value is determined such that the steering output torque To increases as the detected steering input torque Ti increases. . 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 Ti and the steering output torque To
The relationship with and 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).

If an obstacle is detected in step 3, it is determined whether or not the vehicle is traveling normally depending on whether or not the change in the steering output torque To corresponding to the detected steering input torque Ti within the set time exceeds the set value. That is, it is determined whether or not 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. It should be noted that the steering output torque To varies slightly even in a steady state due to the influence of disturbance due to the unevenness of the road surface or the influence of electrical noise on the torque sensor 3.
Has.

If it is determined in step 4 that the vehicle is running normally and the steering output torque To corresponding to the steering input torque Ti changes within the set time and the steering is started, The steering output torque To
It is determined from the sign of 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 5).

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

FIG. 8 shows the procedure for determining the urgency level of the steering.
It is shown in the flowchart. 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 judgment, when the two urgency levels match, the urgent level is taken as a temporary judgment result (step 102), and when the two urgency levels do not match, the emergency corresponding to the changing acceleration is taken. The degree level is used as a temporary determination result (step 103).

Next, it is determined whether or not the urgency level based on each temporary 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 temporary judgment result is not the boundary of the two urgency levels or in the vicinity of the boundary, the urgency level based on the temporary judgment result is taken as the judgment result (step 105). .

As a result of the judgment, if the urgency level based on the tentative judgment result is the boundary of the two urgency levels or near the boundary, the steering output torque at the time when a set time (for example, 0.1 seconds) has elapsed from the start of steering. It is determined whether To decreases within the subsequent set time (for example, 0.4 seconds) (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 subsequent set time, the higher one of the two emergency levels is taken as the judgment result (step 107), and the subsequent setting is made. 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 in 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). .

When the maximum value P of the absolute value of the steering output torque To stored in step 7 is not updated, the change of the stored steering output torque To changes the steering output torque To exceeding the maximum value Q of the absolute value of the acceleration. It is determined whether the acceleration is obtained, that is, whether the maximum value Q is updated (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, steering assist is achieved by applying the motor drive control current value calculated in step 2 to the motor 13. Perform (step 9). Thereafter, the process returns to step 1.

When the maximum absolute value P of the steering output torque To stored in step 7 is updated, or the steering output torque To stored in 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, the judgment level of the urgency level is set,
Also, the setting of the steering suppression strength is changed (step 1
1). That is, "urgent", "quick", "normal",
The change amount of the steering output torque To, which is the criterion for the boundary of the urgency level of “slow”, the change acceleration of the steering output torque To, and the respective values of the torque added by the motor 13 for suppressing the steering are Change to the value associated with the updated driver characteristic level. After the setting change, the steering assist is performed in step 9 described above. Step 1
If the driver characteristic level is not updated at 0,
In step 9 as it is, steering assist is performed.

When it is determined in step 4 above that the vehicle is not in a steady running state, that is, when steering is in progress,
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. Alternatively,
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 to decrease by steering to the left after changing the lane to the right becomes the start time point 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 urgency level is determined in step 6 above.

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

The flow chart of FIG. 9 shows the 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 urgency level of steering in the step 6 is below the boundary between "normal" and "slow", that is, the change acceleration of the steering output torque To is below a threshold value of substantially zero. It is judged whether or not (step 2)
01).

If the change acceleration of the steering output torque To is less than or equal to the threshold value, the set time thereafter (for example, 0.1 seconds)
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 less than the threshold value, it is determined whether or not the change acceleration decreases within a subsequent set time (for example, 0.1 seconds) (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.

When it is determined in step 14 that the purpose of steering is not lane change but lane change, the initial steering suppression time t1 is set in order to suppress steering (step 15). The initial steering suppression time t1 is shortened as the urgency level of steering is higher, and is longer as the urgency level of steering is lower.
This is because the higher the urgency level of steering is, the higher the necessity of avoiding a front obstacle is. Therefore, by shortening the initial steering suppression time t1, the risk of collision with a front obstacle can be reduced. On the other hand, as the urgency level is lower, the necessity of avoiding the front obstacle is lower, so the initial steering suppression time t1
This is because there is no possibility of collision with an obstacle ahead even if the length is increased. Also, by increasing the initial steering suppression time t1, it is possible to improve the accuracy of avoiding a collision with a side obstacle or a rear side obstacle. In the present embodiment, the initial steering suppression time t1 is set in three stages according to the urgency level of steering, and is set to the shortest when the urgency level is "quick" and the longest when the urgency level is "slow". It is set, and in the case of "normal", it is set to an intermediate length between "quick" and "slow". A specific set length of the initial steering suppression time t1 can be obtained by an experiment.

After that, steering is suppressed (step 16). 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. While the steering is being suppressed, the voice alarm 52 warns the driver by voice of the danger of collision.

Next, the set initial steering suppression time t1
Is determined (step 17). If the initial steering suppression time t1 has not elapsed, the steering suppression is continued. If the initial steering suppression time t1 has elapsed,
The final steering suppression time t2 corresponding to the time until the steering suppression is released is set (step 18). The final steering suppression time t2 is shortened as the emergency level at the start of steering becomes higher and shorter as the emergency level is lower, and shortened as the initial steering suppression time t1 becomes shorter and longer as the initial steering suppression time t1 increases. The larger the steering input torque Ti after the passage of t1, the shorter the steering input torque Ti, and the smaller the steering input torque Ti, the longer the steering input torque Ti. This is because the higher the urgency level is, the shorter the initial steering suppression time t1 is,
Steering input torque T when the initial steering suppression time t1 has elapsed
The larger i is, the higher the necessity of avoiding the front obstacle is. Therefore, by shortening the final steering suppression time t2, the possibility of collision with the front obstacle can be reduced. On the other hand, the lower the urgency level, the longer the initial steering suppression time t1, and the smaller the steering input torque Ti when the initial steering suppression time t1 elapses, the lower the necessity of avoiding the front obstacle is. This is because there is no possibility of collision with a front obstacle even if the final steering suppression time t2 is lengthened. Further, by increasing the final steering suppression time t2, it is possible to improve the accuracy of avoiding a collision with a side or rear side obstacle. The specific set length of the final steering suppression time t2 can be obtained by an experiment.

By setting the final steering suppression time t2 according to the steering input torque Ti when the initial steering suppression time t1 has elapsed, the total set length of the steering suppression time is the steering input torque Ti during the steering suppression. Corresponding to the size of. As a result, it is possible to cope with a change in the urgency level during the steering suppression. That is, when the urgency of steering increases during steering suppression, for example, as shown in FIG. 11, the initial steering suppression time t1 during which steering is suppressed because another vehicle C is behind the own vehicle A. In the case where the obstacle B suddenly appears in the front, the driver increases the steering input torque Ti against the steering suppression. in this case,
When the initial steering suppression time t1 elapses, that is, during the steering suppression, the steering input torque T1 increases as compared with the case where the emergency level does not change. As a result, when the urgency level increases during the steering suppression, the final steering suppression time t2 is shortened, the steering suppression is released in a short time, and the additional torque Ta is applied as the steering assist force to obtain the steering output torque To. It is possible to generate and avoid the front obstacle B.
Further, when the urgency of the steering decreases while the steering is suppressed, for example, when the front obstacle disappears, the driver reduces the steering input torque Ti. In this case, the steering input torque T1 when the initial steering suppression time t1 has elapsed
Is less than if the urgency level did not change.
As a result, when the urgency level decreases during the steering suppression, the final steering suppression time t2 is lengthened to lengthen the time until the steering suppression is released to avoid the collision with the side or rear side obstacles. The accuracy can be improved. The criteria for the urgency level are
Since it corresponds to the driver characteristic level as described above, the set length of the steering suppression time can be appropriately determined according to the magnitude of the steering input torque Ti during the steering suppression and the driver characteristic level.

Next, the set final steering suppression time t2
Is determined (step 19). If the final steering suppression time t2 has not elapsed, the steering suppression is continued. When the final steering suppression time t2 has elapsed, the steering suppression is released (step 20).

If the steering suppression is released, it is determined whether or not the 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. It is determined (step 21).

When the maximum value of the absolute value R of the steering input torque Ti stored in step 21 is not updated, steering assist is performed in step 9. When updating the maximum absolute value R of the steering input torque Ti stored in step 21, the strength of the driver characteristic level corresponding to the updated maximum absolute value R of the steering input torque Ti is determined in step 10. , It is determined whether or not the strength of the stored driver characteristic level is exceeded, that is, whether or not the driver characteristic level is updated. When the driver characteristic level is updated, the setting of the determination standard of the urgency level and the setting of the steering suppression strength are changed in step 11, and when the driver characteristic level is not updated, the steering assist is performed in step 9.

If the steering direction is not in the direction of the detected obstacle in step 12, or if it is determined in step 13 that the steering is a route correction steering, that is, if there is no possibility of collision, the absolute value of the stored steering output torque To is absolute. It is determined whether or not the steering output torque To that exceeds the maximum value P of the values is obtained, that is, whether or not the maximum value P is updated (step 22).

If the maximum absolute value P of the steering output torque To stored in step 22 is not updated, steering assist is performed in step 9. When the maximum absolute value P of the steering output torque To stored in step 22 is updated, in step 10, the strength of the driver characteristic level corresponding to the updated maximum absolute value P 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 the driver characteristic level is updated. When the driver characteristic level is updated, the setting of the determination standard of the urgency level and the setting of the steering suppression strength are changed in step 11, and when the driver characteristic level is not updated, the steering assist is performed in step 9.

FIG. 12 shows a state in which the other vehicle C is made to follow the right rear of the own vehicle A having the above-mentioned configuration and the vehicle is traveling to the right 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. Thereafter, the distance between the own vehicle A and the other vehicle C was increased, and steering was performed at a position where the other vehicle C could not be detected by the sensor for lane change at an emergency level of "quick" or lower. 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 state in which the other vehicle C is made to follow the right rear of the own vehicle A having the above-mentioned structure and the vehicle is traveling to the right in the figure. In this state, the other vehicle C is detected by the sensor.
At the position where the vehicle is detected, the steering for changing the lane was performed at the emergency level of "emergency" in order to avoid the front obstacle B. 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 the conventional steering suppression control is performed in this case, as shown in (2) of FIG. 13, 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. Therefore, the host vehicle A and the obstacle B may collide.

FIG. 14A shows a state in which steering for entering a curve is carried out at a position where another vehicle C on the inner side of the own vehicle A having the above-mentioned structure can be detected by a sensor. 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 vehicle A having the above-mentioned structure overtakes the other vehicle C in front and the course correction steering is performed at a position where the other vehicle C can be detected by the 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 embodiment, the steering output torque T
The steering suppression start time is determined by determining the presence or absence of steering based on o, and the additional torque Ta generated as the steering suppression torque is determined so that the steering output torque To has a predetermined value. The steering suppression time is determined corresponding to the emergency level determined based on the change in the steering output torque To. 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 steering input torque Ti
Fluctuations are offset by changes in the applied torque. Therefore,
The influence of the disturbance due to the unevenness of the road surface or the like on the steering output torque To and the influence of the electrical 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,
Whether or not steering is being performed can be accurately determined, and proper steering suppression can be prevented from being impeded. Further, since the steering output torque To has a phase ahead of other characteristics corresponding to the behavior change of the host vehicle A, for example, the steering angle and the yaw rate, the host vehicle A
The behavior change of can be detected early and the responsiveness of the control system can be improved. In addition, since the value detected for steering assistance can be detected as a value corresponding to the steering output torque To, a dedicated sensor for detecting a behavior change of the vehicle, for example, a shaft on which the rack 7 acts on the steering wheel 8. Since it is not necessary to provide a directional force sensor or the like, the cost can be reduced without complicating the structure.

Further, for a driver having a comparatively strong force or a driver who steers comparatively abruptly for rough driving, the strength of the steering suppression is increased, while a driver with a comparatively weak force or steering is used. The degree of steering suppression can be weakened for a driver who performs relatively gently, and the steering can be suppressed with an appropriate strength according to the characteristics of the driver. 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. Further, the increase or decrease of the steering input torque Ti when the urgency level of the steering changes while the steering is suppressed varies depending on the characteristics of the driver. For drivers who perform the same, the threshold of the boundary of the urgency level is raised, while for drivers with a relatively weak force or drivers who perform steering relatively gently, the criterion of the boundary of the urgency level is lowered. Thus, the change in the urgency level can be appropriately determined according to the driver characteristic, and the steering suppression time can be appropriately set according to the driver characteristic. That is, it is possible to determine the urgency level of steering according to the strength of the driver's characteristic level, control the strength of steering suppression, and control the steering suppression time, so control the steering suppression appropriately according to the characteristics of the driver. Can be done.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the maximum absolute value of the steering output torque To, the maximum absolute value of the change acceleration of the steering output torque To, and the maximum absolute value of the steering output torque To during actual vehicle driving are used as values corresponding to the strength of the driver characteristic level. The maximum absolute value of the steering input torque Ti is calculated, and the setting of the determination standard of the urgency level and the setting of the steering suppression strength are changed according to the calculated value. Before starting, the value corresponding to the strength of the driver characteristic level is obtained in the stopped state, and the setting of the determination standard of the emergency level and the setting of the steering suppression strength may be changed according to the obtained value. . That is, as shown in the flowchart of FIG. 17, first, the check mode display is performed on the liquid crystal display device mounted on the 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 is for instructing the driver the steering input necessary to detect the strength of the driver characteristic level. For example, "Please rotate the steering wheel as quickly as possible with as much force as possible." Display. 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 and stored in the controller 50. Next, the setting of the judgment standard of the urgency level and the setting of the steering suppression strength are changed according to the stored value (step 304).

Further, a volume knob capable of changing the value corresponding to the strength of the driver characteristic level is provided, and the strength of the driver characteristic level can be changed by the driver himself by the operation of the knob. The setting of the determination standard of the degree level and the setting of the steering suppression strength may be changeable.

Further, although the steering input torque is detected as the value corresponding to the steering output torque in the above embodiment, the steering input torque and the drive control value of the motor 13 may be detected in time series instead. . In this case, instead of the relationship between the steering input torque and the steering output torque as shown in FIG. 10, the controller 50 stores a predetermined relationship between the drive control current value of the motor 13 and the steering input torque. When steering assist is performed, the motor 13 is driven by a drive control current value associated with the detected steering input torque based on the stored relationship. Accordingly, the detected steering input torque and the drive control current value are associated with the steering output torque.

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

The method of steering assist or 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.

[0095]

According to the vehicle steering system of the present invention, the steering can be suppressed appropriately according to the characteristics of the driver and the urgency level of the steering, and further, the urgency level changes during the steering suppression. Can respond appropriately.

[Brief description of 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.

FIG. 11 is an explanatory diagram of a steering suppressing action according to 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 operation explanatory view in the case where the steering state determination whether or not the route 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 driver characteristic level detection procedure according to a modified example of the present invention.

[Explanation of symbols]

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

Claims (6)

[Claims] 1. A steering system for a vehicle capable of suppressing steering based on the possibility of collision with an obstacle, the vehicle steering comprising a means capable of changing the setting of the strength of the steering suppression according to the characteristics of the driver. apparatus. 2. In a vehicle steering system capable of suppressing steering based on the possibility of collision with an obstacle, means for time-sequentially detecting a value corresponding to a steering output torque, and steering based on the detected value. The steering state determination means for determining the urgency level of the driver, the means for setting the steering suppression time according to the urgency level, and the setting of the value corresponding to the steering output torque which is the criterion for determining the urgency level are set by the driver. And a means for changing the characteristics according to the characteristics of the vehicle. 3. The steering apparatus for a vehicle according to claim 2, further comprising means capable of changing the setting of the steering suppression strength according to the characteristics of the driver. 4. The steering state determination means stores means for storing a predetermined correspondence between the amount of change in the steering output torque within a set time from the start of steering and the urgency level of steering, and the time when the set time elapses. Means for storing a predetermined correspondence between the change acceleration of the steering output torque and the urgency level thereof, and the urgency level corresponding to the change amount of the steering output torque corresponding to the detected value within the set time. And means for determining whether or not the steering output torque corresponding to the detected value and the urgency level corresponding to the change acceleration at the time when the set time has elapsed match. The vehicle steering system according to claim 2, wherein the emergency level is determined. 5. The driver characteristic is at least one of a maximum absolute value of a steering output torque, a maximum absolute value of a change acceleration of the steering output torque, and a maximum absolute value of a steering input torque. The vehicle steering system according to claim 4, further comprising means for determining the strength of the driver characteristic level corresponding to one of the two. 6. A means for detecting steering input torque in time series, wherein the set length of the steering suppression time corresponds to the magnitude of the steering input torque during the steering suppression and the characteristics of the driver. 6. The vehicle steering system according to any one of 5 above.