JP2004196100A - Steering control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize control of steering transmitting characteristics optimum for recognizing driving behavior of a driver, controlling the steering transmitting characteristics corresponding to the driving behavior and carrying out specific driving behavior of the driver in steering control of a vehicle. <P>SOLUTION: In the steering device for a vehicle, a ratio (in the following, referred to a steering angle ratio) of a steering amount θ inputted to a steering wheel by the driver and a steered angle δw of a steered wheel 9 is varied. A traveling environment detection means 22 detect traveling environment of the vehicle based on an information from a front side road state detection means 12 and a car speed sensor 13. Thereby, a driving behavior recognition means 21 recognizes the specific driving behavior of the driver (maintaining of lane or changing of the lane) and a steering angle ratio Nd is determined in a steering angle ratio (steering transmitting characteristic) setting means 25 based on the result of the recognition. When a steering angle ratio (steering transmitting characteristic) correction coefficient determination means 24 recognizes starting of change of the lane Cs, it calculates a steering angle ratio correction coefficient Kp. A steering angle ratio (steering transmitting characteristic) correction means 27 corrects the steering angle ratio Np based on the coefficient Kp. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a steering control device for a vehicle, and particularly to a steering transmission characteristic that is a ratio between a steering amount of a steering wheel and a steering angle of a steered wheel according to a driving behavior, such as whether or not a lane change is being performed. The present invention relates to a steering control device that can be changed.
[0002]
[Prior art]
Conventionally, as a vehicle steering control device capable of changing a steering transmission characteristic which is a ratio of a steering angle of a steered wheel to a steering amount input to a steering wheel by a driver according to a traveling state of a vehicle, for example, Patent Documents 1 and 2 There is something like the description.
[0003]
[Patent Document 1]
JP-A-9-0558507
[Patent Document 2]
JP-A-11-005550
[0004]
In the vehicle steering control device described in Patent Document 1, a steering amount input to a steering wheel is transmitted to a pinion via a variable steering gear ratio mechanism, and a rack shaft meshed with the pinion moves by rotation of the pinion. In this case, the steering wheel is steered, and at this time, the running performance is improved by changing the steering gear ratio according to the vehicle speed.
[0005]
In addition, a steering control device for a vehicle described in Patent Document 2 includes a steering angle ratio varying unit that varies a ratio between a steering amount input to a steering wheel and a steering angle of a steered wheel, and a steering reaction force of the steering wheel. And a steering reaction force variable means for changing the steering angle, and the steering angle ratio and the steering reaction force are changed according to the driving difficulty level. is there.
[0006]
[Problems to be solved by the invention]
However, the conventional vehicle steering control device has the following problems.
[0007]
That is, in the vehicle steering control device described in Patent Literature 1, since the steering gear ratio is set only by the vehicle speed, factors such as the road surface condition and the driver's steering condition are considered in the low-to-medium vehicle speed range. Without having a large steering gear ratio.
In addition, because the steering gear ratio is large, the vehicle responds to small steering even when steering input for changing the direction of the vehicle is not necessary, such as when the vehicle is going straight ahead, and stability when traveling straight ahead. Is impaired.
Furthermore, for the same reason, the driver must always pay attention to the steering in order to keep the vehicle straight, which increases the psychological burden on the driver.
[0008]
Further, in the vehicle steering control device described in Patent Document 2, in order to reduce the burden on the driver, the steering angle ratio and the steering reaction force are changed according to the driving difficulty level. Depending on the degree of steering operation, different driving difficulty levels may be detected even in the same driving environment.If the steering characteristics such as the steering angle ratio and steering reaction force are not constant, It is difficult to understand what kind of driving operation should be performed.
Further, since the traveling environment of the vehicle is not directly reflected in the steering angle ratio varying means and the steering reaction force varying means, the steering characteristics are not set so as to appropriately control the position of the vehicle during traveling. There are concerns about such issues.
[0009]
The present invention makes it possible to individually set a steering transmission characteristic represented by a steering gear ratio (steering angle ratio) for each specific driving behavior such as a lane change, and converts the set steering transmission characteristic into a specific driving behavior. If it is used for steering control after correcting based on the driving situation when
For example, even under a complicated driving situation such as changing lanes during turning, the steering transmission characteristics are adapted to the driving situation, and good steering control is always possible for the driver's driving operation. From the point of view,
It is an object of the present invention to propose a vehicle steering control device that embodies this idea and can solve all of the problems and concerns described above.
[0010]
[Means for Solving the Problems]
For this purpose, a vehicle steering control device according to the present invention is configured as described in claim 1.
It is assumed that a vehicle steering device that obtains a target steering angle based on a driver's steering amount detected by the steering amount detection means and a changeable steering transmission characteristic, and turns the steered wheels by the target steering angle by the steering means. ,to this,
Driving behavior recognition means for recognizing a specific driving behavior of the driver;
When the specific driving behavior is recognized by this means, a steering transmission characteristic setting means for making a steering transmission characteristic a characteristic suitable for the specific driving behavior;
A steering transmission characteristic correction means for correcting the steering transmission characteristic set by this means in accordance with the detected steering amount when the specific driving action is recognized and contributing to the calculation of the target steering angle. It was done.
[0011]
【The invention's effect】
According to the configuration of the present invention, the steering transfer characteristic is set for each specific driving action, and the set steering transfer characteristic is corrected based on the detected steering amount when the specific driving action occurs. Will contribute to the calculation of the target rudder angle,
For example, even under a complicated driving situation such as changing lanes during turning, the steering transmission characteristics are surely adapted to the complicated driving situation taking into account all of these turning and lane changes. Good steering control for the driver's driving operation can always be compensated.
Therefore, in the low and medium vehicle speed range, the steering transmission characteristics unconditionally become large and the straight running stability is impaired during straight running, or the above-mentioned problem that the psychological burden on the driver increases in order to maintain straight running,
For example, under a complicated driving situation such as changing lanes during turning, all driving factors are not reflected in the control of the steering transmission characteristic and the steering transmission characteristic does not match the complicated driving situation The above problem can be solved.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a control system diagram of a vehicle including a steering control device according to an embodiment of the present invention.
Reference numeral 1 denotes a steering wheel 1 operated by a driver to steer the vehicle. The steering wheel 1 is fixed to one end of a steering column shaft 2, and a steering torque providing means 3 is provided at the other end of the steering column shaft 2. A steering amount detecting means 4 is provided.
The turning means 6 is constituted by, for example, a rack and pinion type steering gear and a turning actuator such as an electric motor for driving the pinion, and both ends of the rack 7 are connected to knuckles 8L and 8R of left and right steered wheels 9L and 9R. Then, the left and right steered wheels 9L and 9R are steered.
[0013]
However, the steering column shaft 2 and the turning means 6 are not mechanically connected to each other, but are correlated electronically via the electronic control unit 11.
The electronic control unit 11 responds to a signal relating to the steering amount θ of the steering wheel 1 detected by the steering amount detecting means 4, a signal from the road condition detecting means 12 in front, and a signal from the vehicle speed sensor 13 to respond to a signal to be described later. In this manner, the target steering angle δw is obtained, and a signal relating thereto is received by the steering means 6 to steer the left and right steered wheels 9L and 9R by the target steering angle δw.
[0014]
The forward road condition detecting means 12 detects, for example, a white line by performing image processing on an image obtained by photographing the front of the vehicle with a camera installed on an inner mirror or the like, and using the information to determine a curvature of the traveling road, a navigation system, or the like. And a method of calculating the curvature of the traveling path from the information of the road.
The vehicle speed sensor 13 detects a vehicle speed VSP.
The road condition data and the vehicle speed VSP are transmitted to the traveling environment detecting means 22 of the electronic control unit 11.
[0015]
The electronic control unit 11 includes a driving behavior recognizing unit 21, a steering torque output characteristic control unit 23, a steering angle ratio (steering transmission characteristic) correction coefficient determining unit 24, a steering angle ratio (Steering transmission characteristic) setting means 25, target steering angle calculating means 26, and steering angle ratio (steering transmission characteristic) correcting means 27, which are configured to be correlated as shown in the figure.
The steering torque output characteristic control means 23 determines a steering torque target value based on the steering amount θ detected by the steering amount detection means 4, and upon receiving a signal related to the steering torque target value, the steering torque providing means 3 It functions to give the steering reaction force.
[0016]
The driving environment detecting means 22 obtains the driving environment of the vehicle based on the vehicle speed VSP detected by the means 13 and the road condition data obtained as described above by the means 12, and transmits the obtained driving environment to the driving action recognizing means 21.
The driving behavior recognition means 21 recognizes the driving behavior of the driver at predetermined time intervals based on the driving environment, and determines whether this is a specific driving behavior, for example, lane keeping or lane change, The judgment result DSd is transmitted to the steering angle ratio correcting means 24 and the steering angle ratio setting means 25.
As a method for the above determination, for example, a method described in a literature (Pentland, A. et al., Modeling and Prediction of Human Behavior, Neural Computation, 11 229-242, 1999) is used.
This is a technique for stochastically estimating a driver's driving behavior strategy based on a hidden Markov model, and the document shows that a driving behavior strategy of keeping a lane while driving and changing lanes can be detected. ing.
[0017]
The determination result DSd by the means 21 is stored as a profile, and when the determination result of lane change appears after the determination result of lane keeping continues for a predetermined time or more using the profile, the lane change as a specific driving action is performed. It is assumed that there is a start Cs, the lane change end Ce, which is a specific driving action, is determined when the lane maintenance determination result appears after the lane change determination result has continued for a predetermined time or more. Then, the lane change end Ce can be recognized. These recognition results are transmitted to the steering angle ratio setting means 25 and the steering angle ratio correction coefficient determining means 24.
[0018]
As a method for the recognition, the lane change start Cs and the lane change end Ce may be detected by the driver's operation of the turn signal (direction indicator).
[0019]
The steering angle ratio setting means 25 obtains the steering angle ratio Nd from the above determination result DSd by searching on the previously stored characteristic diagram shown in FIG. In the case of maintaining the lane of DSd = Ce, the steering angle ratio Nd is set to N1 where the change ratio of the target steering angle δw to the steering amount θ is small (the steering gain is small), and in the case of the lane change of DSd = Cs, the steering angle is changed. The ratio Nd is N2 (N1 <N2) where the steering gain is small.
Thereby, when the driving result determination result DSd indicates that the lane is to be maintained, the straightness of the vehicle is improved by decreasing the steering angle ratio Nd (steering gain) (N1). By increasing the ratio Nd (N2), the turning performance of the vehicle is improved.
[0020]
By the way, when the lane change start Cs is recognized during the steering operation such as when traveling on a curve, it is considered that the driver predictively performs the next steering operation based on the steering angle ratio Nd at that time.
In this case, if the steering angle ratio Nd is suddenly increased from N1 to N2 in response to the recognition of the lane change start Cs, the vehicle may turn more than the driver predicts, which may adversely affect the driving operation. Is done.
On the other hand, when the position of the steering wheel 1 is near neutral and the detected steering amount θ is small at the time when the lane change start Cs is recognized, the steering angle ratio Nd is changed from N1 to N2 because the driver has not originally performed steering. The above problem that the vehicle turns sharper than expected by the driver does not occur even if it is increased.
[0021]
Therefore, in the steering angle ratio correction coefficient determining means 24, when the driving action recognizing means 21 recognizes the lane change start Cs, if the detected steering amount θlco at that time is less than a predetermined value ± θo1 shown in FIG. As shown in the figure, the steering angle ratio correction coefficient Kp is set to 1 so as not to perform the correction of Nd, and when the detected steering amount θlco at the start of the lane change is larger than a predetermined value ± θo1, the correction of the steering angle ratio Nd will be described later. The steering angle ratio correction coefficient Kp is set to less than 1 as shown in FIG.
Here, the characteristic of the steering angle ratio correction coefficient Kp when the detected steering amount θlco at the start of the lane change is larger than the predetermined value ± θo1, as shown in FIG. It gradually decreases to 0 as it increases from θo1 toward ± θo2, that is, as represented by the following equation,
Kp = {-1 / (θo2-θo1)} θlco + θo2 / (θo2-θo1) (1)
It is assumed that the detected steering amount θlco at the start of the lane change is kept at 0 in an area larger than the predetermined value ± θo2.
[0022]
The steering angle ratio correction means 27 is a steering angle ratio Nd (= N1) for lane keeping (DSe = Ce) and a steering angle ratio Nd (= N2) for lane change (DSe = Cs) obtained by the means 25 as described above. And the steering angle ratio correction coefficient Kp (see FIG. 3) determined according to the detected steering amount θlco at the start of the lane change as described above by means 24, and based on these, the detected steering amount θlco at the start of the lane change. However, if it is equal to or smaller than the predetermined value ± θo1 shown in FIG. 3, the corrected steering angle ratio Np is set to the steering angle ratio N2 for changing lanes in response to Kp = 1. That is,
0 <| θlco | ≦ | θo1 |
Np = N2 (2)
And
[0023]
When the detected steering amount θlco at the start of the lane change is larger than the predetermined value ± θo1 and smaller than ± predetermined value θo2, as the steering angle θlco approaches the predetermined value ± θo2, the corrected steering angle ratio Np becomes Nd = The corrected steering angle ratio Np is obtained from N2 so as to approach Nd = N1, for example, by the following equation. That is,
In | θo1 | <| θlco | <| θo2 |, the steering angle ratio correction coefficient Kp obtained by the above equation (1), the lane keeping steering angle ratio N1 and the lane changing steering angle ratio N2 are used. Then, the corrected steering angle ratio Np is obtained by the following equation.
Np = (1−Kp) N1 + Kp · N2 (3)
[0024]
When the detected steering amount θlco at the start of the lane change is larger than the predetermined value ± θo2, the corrected steering angle ratio Np is set to the lane keeping steering angle ratio N1 in response to Kp = 0. That is,
In | θo2 | ≦ | θlco |,
Np = N1 (4)
And
[0025]
The corrected steering angle ratio Np obtained as described above is transmitted to the target steering angle calculating means 26.
The target steering angle calculating means 26 receives a signal related to the steering wheel steering amount θ in addition to the corrected steering angle ratio Np, and calculates a target steering angle δw of the left and right steered wheels 9L and 9R based on the following equation. To the turning means 6 to turn the left and right steered wheels 9L and 9R by the target steering angle δw.
δw = Np × θ (5)
[0026]
Although the electronic control unit 11 is shown in FIG. 1 as a functional block diagram, the electronic control unit 11 can perform the same steering control by the processing shown in the flowchart of FIG.
4 is repeatedly executed at predetermined time intervals. First, in step S1, the road curvature detected by the front road condition detecting means 12 in FIG. 1 and the vehicle speed VSP detected by the vehicle speed sensor 13 in FIG. Enter as
The driving environment data is used arbitrarily in combination to constitute the driving action recognition means 21, and is not specified by the information described here.
[0027]
In the next step S2, the steering amount θ of the steering wheel 1 by the driver is input, and the steering amount θ detected by the steering amount detection means 4 shown in FIG. 1 is read.
[0028]
In step S3, the same processing as performed by the driving behavior recognition means 21 of FIG. 1 is performed, and lane keeping or lane change is determined based on the driver's driving behavior DSd, and lane change start Cs or lane change end Ce is recognized. .
[0029]
In step S4, it is checked whether or not the lane change start DSd = Cs. If it is the lane change start Cs, the process proceeds to step S5, and N2 is stored in the steering angle ratio Nd.
On the other hand, in cases other than the lane change start Cs, the process proceeds to step S11, and it is checked whether the driving action DSd is the lane change end Ce.
When lane change end DSe = Ce, N1 is stored in the steering angle ratio Nd in the next step S12.
On the other hand, in cases other than the lane change end Ce, since the lane keeping or the lane change is being executed, the steering angle ratio Nd is held at the previous value Nd in step S13.
[0030]
In step S6, which is selected after storing N2 in the steering angle ratio Nd in step S5 at the start of the lane change, in step S6, the steering angle ratio Nd based on the detected steering amount θlco at the start of the lane change when the lane change start Cs is recognized. A correction coefficient Kp is calculated.
First, when it is determined that the detected steering amount θlco at the start of the lane change exceeds the predetermined value θo2, 0 is stored in the correction coefficient Kp so that the steering angle ratio Nd becomes the lane keeping steering angle ratio N1.
Next, when it is determined that the detected steering amount θlco at the start of the lane change is larger than the predetermined value θo1 and smaller than the predetermined value θo2, a map search is performed on the characteristic diagram shown in FIG. A value corresponding to the detected steering amount θlco at the start of the lane change is stored in the coefficient Kp in the range of 0 to 1, and the steering angle ratio Nd is changed according to the increase in the detected steering amount θlco at the start of the lane change. The lane keeping steering angle ratio N1 is gradually reduced from the ratio N2.
Finally, when it is determined that the detected steering amount θlco at the start of the lane change is smaller than the predetermined value θo1, 1 is set to the correction coefficient Kp so that the steering angle ratio Nd is not corrected from the lane changing steering angle ratio N2. Store.
[0031]
In step S7, the corrected steering angle ratio Np is calculated by the above equation (1) using the correction coefficient Kp, the lane keeping steering angle ratio N1 and the lane changing steering angle ratio N2.
[0032]
If it is determined in step S4 that it is other than the lane change start Cs, the above-described correction of the steering angle ratio Nd is not performed. Therefore, Nd is stored in the corrected steering angle ratio Np in step S14 selected at the time of the determination.
[0033]
Based on the corrected steering angle ratio Np obtained in the above step S7 or step S14, in step S8, the target steering angle δw of the steered wheels 9L, 9R is obtained from the above equation (6) according to the steering wheel steering amount θ. To the turning means 6 of FIG.
[0034]
By the way, according to the present embodiment, when the driving behavior recognizing means 21 for recognizing the specific driving behavior of the driver and the lane change start Cs which is the specific driving behavior are recognized, the steering transmission characteristic is changed. A steering transmission characteristic setting means 25 which is a characteristic suitable for a specific driving action (Cs); and a steering transmission characteristic set by the means 25, the detected steering amount when the specific driving action (Cs) is recognized. Since the steering transmission characteristic correction means 27 which contributes to the calculation of the target steering angle δw by correcting according to θlco is provided, the steering transmission characteristic is set for each specific driving action, and the steering transmission characteristic thus set is set. Is corrected based on the detected steering amount when a specific driving action occurs, which contributes to the calculation of the target steering angle, for example, even under a complicated driving situation such as changing lanes during turning. In addition, the steering transmission characteristics are surely adapted to the complicated driving situation in consideration of all of the turning operation and the lane change, and it is possible to always compensate for the steering control that is good for the driver's driving operation.
Therefore, at low and medium vehicle speeds, the steering transmission characteristics are unconditionally increased, linear stability is impaired when traveling straight ahead, and the psychological burden on the driver increases in order to maintain straight traveling. In a complicated driving situation such as changing lanes, the above-mentioned problem that all the driving factors are not reflected in the control of the steering transmission characteristic and the steering transmission characteristic does not conform to the complicated driving situation is solved. Can be eliminated.
[0035]
In addition, since the driving behavior recognizing means 21 recognizes the start Cs of the lane change and the end Ce of the lane change as the specific driving behavior, it is possible to appropriately adjust the steering transmission characteristic when starting and ending the lane change operation. Can be controlled.
[0036]
Further, according to the present embodiment, when the driving behavior recognizing unit 21 recognizes the start Cs of the lane change, the steering transfer characteristic correcting unit 27 detects the steering as the detected steering amount | θlco | Since the steering transmission characteristic is corrected so that the rate of change of the target steering angle δw with respect to the amount becomes small, the driver predicts even when changing lanes during turning such as when traveling on a curve. It is possible to prevent a change to a steering transmission characteristic that did not exist. That is, the steering angle ratio Np is prevented from increasing and the vehicle is prevented from turning more than predicted by the driver, and the driver can perform the steering operation while predicting the next steering transmission characteristic.
[0037]
Further, according to the present embodiment, when the driving behavior recognizing unit 21 recognizes the start Cs of the lane change, the steering transfer characteristic correcting unit 27 sets the absolute value of the detected steering amount θlco at the start of the lane change to the set steering. If the absolute value of the amount θo2 is equal to or more than the absolute value, the steering transmission characteristic Np is set to the characteristic N1 immediately before the start of the lane change is recognized. By changing the steering angle ratio Np, it is possible to prevent the vehicle from turning unexpectedly by the driver.
[0038]
Next, another embodiment of the present invention will be described with reference to the drawings.
FIG. 5 is a control system diagram of a vehicle including a steering control device according to another embodiment of the present invention. Since the basic configuration is the same as that of the control system diagram shown in FIG. 1, the same reference numerals are used, and different components will be described here. Using the traveling environment of the vehicle obtained by the traveling environment detecting means 22, the lane reaching index calculating means 28 calculates the lane reaching index lcr as described later, and transmits it to the steering angle ratio correction coefficient determining means 24. When the lane change start Cs is recognized, the steering angle ratio correction means 24 calculates a steering angle ratio correction coefficient Kp according to the lane end reaching index lcr, and the steering angle ratio determined by the steering angle ratio setting means 25. Is corrected.
[0039]
The lane reach index lcr is a lane reach distance dlc from the running vehicle shown in FIG. 6 to the intersection of the vehicle travel direction extension line and the lane, or a reciprocal of a lane reach time tlc obtained by dividing the distance dlc by the vehicle speed VSP. Used. The lane reaching index lcr has a characteristic that it is 0 when the vehicle is parallel to the lane, and that lcr increases as the yaw angle with respect to the lane increases.
[0040]
In the steering angle ratio correction coefficient determining means 24, when the driving behavior recognizing means 21 recognizes the lane change start Cs, if the lane reaching index lcr at that time is not more than a predetermined value lcro1 shown in FIG. As shown in the figure, the steering angle ratio correction coefficient Kp is set to 1 so as not to perform the correction, and when it is larger than a predetermined value lcro1, the steering angle ratio Nd is corrected as shown in FIG. The correction coefficient Kp is set to less than 1.
[0041]
As shown in FIG. 7, when the lane arrival index lcr at the start of lane change is larger than the predetermined value lcro1, the characteristic of the steering angle ratio correction coefficient Kp is such that the lane arrival index lcr at the start of lane change changes from the predetermined value lcro1 to lcro2. It gradually decreases to 0 as the size increases. In other words, as expressed by the following equation,
Kp = ｛-1 / (lcro2-lcro1) lcr + lcro2 // (lcro2-lcro1) (6)
It is assumed that the lane reach index lcr at the start of the lane change is kept at 0 in a region equal to or more than the predetermined value lcro2.
[0042]
In FIG. 5, the electronic control unit 11 is shown by a functional block diagram. However, this electronic control unit can perform the same steering control by the processing shown in the flowchart of FIG. In this figure, step S6 described in FIG. 4 is replaced with steps S26 and S27, and the same reference numerals as those in FIG. 4 are used for common flows. Here, a control flow different from the flowchart shown in FIG. 4 will be described.
[0043]
In step S26, the same processing as that performed by the lane arrival index calculating means 28 in FIG. 5 is performed, and the lane arrival index lcr is calculated based on the vehicle traveling environment such as the vehicle speed VSP and road condition data.
[0044]
In step S27, a coefficient Kp for correcting the steering angle ratio Nd is calculated based on the lane reaching index lcr when the lane change start Cs is recognized. First, when it is determined that the lane end reaching index lcr at the start of the lane change exceeds the predetermined value lcro2, 0 is stored in the correction coefficient Kp so that the steering angle ratio Nd becomes the lane keeping steering angle ratio N1.
Next, when it is determined that the lane end reaching index lcr at the start of the lane change is larger than the predetermined value lcro1 and smaller than the predetermined value lcro2, a map search is performed on the characteristic diagram shown in FIG. 7 from the lane end reaching index lcr. A numerical value corresponding to the lane reaching index lcr at the start of the lane change is stored in the correction coefficient Kp in the range of 0 to 1, and the steering angle ratio Nd is changed for the lane changing according to the increase of the lane reaching index lcr at the start of the lane change. The steering angle ratio N2 is gradually reduced to the lane keeping steering angle ratio N1.
Finally, when it is determined that the lane end reaching index lcr at the start of the lane change is smaller than the predetermined value lcro1, the correction coefficient Kp is set so that the steering angle ratio Nd is not corrected from the lane changing steering angle ratio N2. 1 is stored.
[0045]
According to the present embodiment, the lane reaching index calculation for detecting the lane reaching index lcr which is the reciprocal of the lane reaching distance dlc or the lane reaching time tlc from the running vehicle to the intersection of the vehicle travel direction extension line and the lane. When the driving behavior recognizing means 21 recognizes the start Cs of the lane change, the steering transfer characteristic correcting means 27 adds the detected steering amount θlco at the start of the lane change to the lane arrival index lcr. Since the steering transfer characteristic Np is changed based on the steering transfer characteristic Np, even when the vehicle is traveling near the lane, the steering transfer characteristic Np is adapted to the driving behavior, and the driver performs the lane changing behavior. An appropriate steering angle ratio can be set.
[0046]
When the driving behavior recognizing unit 21 recognizes the start Cs of the lane change, the steering transfer characteristic correction unit 27 changes the target steering angle δw with respect to the detected steering amount θlco as the lane reach index lcr at the start of the lane change increases. Since the steering transmission characteristic Np is changed so that the ratio Np becomes small, when the traveling vehicle arrives at the lane after a short time, when the lane is changed, the steering transmission characteristic that the driver did not predict may be changed. Prevent changes. That is, the steering angle ratio Np is prevented from increasing and the vehicle is prevented from turning more than predicted by the driver, and the driver can perform the steering operation while predicting the next steering transmission characteristic.
[0047]
Further, according to the present embodiment, when the driving behavior recognizing unit 21 recognizes the start Cs of the lane change, the steering transfer characteristic correcting unit 27 determines whether the lane arrival index lcr at the start of the lane change is equal to or larger than the set index lcro2. For example, the steering transmission characteristic Np is set to the characteristic N1 immediately before the start Cs of the lane change is recognized. Therefore, when the traveling vehicle reaches the lane after a very short time, when the lane change is performed, the steering angle is changed. By changing the ratio Np, it is possible to prevent the vehicle from turning in an unexpected range of the driver.
[Brief description of the drawings]
FIG. 1 is a control system diagram of a vehicle including a steering control device according to an embodiment of the present invention.
FIG. 2 is a characteristic diagram showing a relationship between a driving behavior determination result DSd and a steering angle ratio Nd.
FIG. 3 is a characteristic diagram illustrating a relationship between a steering angle θlco at the time of recognition of a lane change start Cs and a steering angle ratio corrector Kp.
FIG. 4 is a flowchart showing a control program executed by an electronic control unit 11 shown in FIG.
FIG. 5 is a control system diagram of a vehicle including a steering control device according to another embodiment of the present invention.
FIG. 6 is a plan view showing a lane reach distance dlc from a running vehicle to an intersection of a vehicle traveling direction extension line and a lane.
FIG. 7 is a characteristic diagram showing a relationship between a lane reaching index lcr at the time of recognition of a lane change start Cs and a steering angle ratio corrector Kp.
8 is a flowchart showing a control program executed by the electronic control unit 11 shown in FIG.
[Explanation of symbols]
1 Steering wheel
2 Steering column shaft
3 Means for providing steering torque
4 Steering amount detection means
6 Turning means
7 racks
8 Knuckles
9 Steering wheel
11 Electronic control unit
12 Forward road condition detecting means
13 Vehicle speed sensor
21 Driving behavior recognition means
22 Driving environment detection means
23 Steering torque output characteristic control means
24 Steering angle ratio (steering transmission characteristics) correction coefficient determining means
25 Steering angle ratio (steering transmission characteristics) setting means
26 Target rudder angle calculation means
27 Steering angle ratio (steering transmission characteristics) correction means
28 Lane arrival index calculating means

Claims (7)

Steering amount detecting means for detecting a steering amount input by the driver, and turning means for turning the steered wheels by a target steering angle corresponding to the detected steering amount,
In a vehicle steering apparatus capable of changing a steering transmission characteristic that is a ratio of the target steering angle to the detected steering amount,
Driving behavior recognition means for recognizing a specific driving behavior of the driver;
When the specific driving behavior is recognized by the means, a steering transmission characteristic setting unit that makes the steering transmission characteristic a characteristic suitable for the specific driving behavior;
A steering transmission characteristic correction means for correcting the steering transmission characteristic set by the means in accordance with the detected steering amount when the specific driving action is recognized, and contributing to the calculation of the target steering angle. Vehicle steering control device. 2. The vehicle steering control device according to claim 1, wherein the driving behavior recognizing means recognizes the start of lane change and the end of lane change as the specific driving behavior. . 3. The vehicle steering control device according to claim 2, wherein the steering transfer characteristic correction unit is configured such that, when the driving behavior recognition unit recognizes the start of the lane change, the larger the detected steering amount at the start of the lane change, the larger the detected steering amount. A steering control device for a vehicle, wherein the steering transmission characteristic is changed so that a change ratio of a target steering angle to a detected steering amount is reduced. 4. The vehicle steering control device according to claim 2, wherein the steering transfer characteristic correction unit sets the detected steering amount at the start of the lane change when the driving behavior recognition unit recognizes the start of the lane change. 5. If the steering amount is equal to or more than the steering amount, the steering transmission characteristic is a characteristic immediately before the start of the lane change is recognized. 5. The vehicle steering control device according to claim 2, wherein the lane is a reciprocal of a lane reach distance or a lane reach time from a running vehicle to an intersection of the vehicle travel direction extension line and the lane. Having a lane arrival index calculating means for detecting the arrival index,
The steering transfer characteristic correction unit changes the steering transfer characteristic based on the lane arrival index instead of the detected steering amount at the start of the lane change when the driving behavior recognition unit recognizes the start of the lane change. A vehicle steering control device, comprising: 6. The vehicle steering control device according to claim 5, wherein the steering transfer characteristic correction unit is configured such that, when the driving behavior recognition unit recognizes the start of the lane change, the larger the lane arrival index at the time of the start of the lane change, the larger the steering transfer characteristic correction unit. A steering control device for a vehicle, wherein the steering transmission characteristic is changed so that a change ratio of a target steering angle to a detected steering amount is reduced. 7. The vehicle steering control device according to claim 5, wherein the steering transfer characteristic correction unit sets the lane arrival index at the start of the lane change when the driving behavior recognition unit recognizes the start of the lane change. 8. If the index is equal to or more than the index, the steering transmission characteristic is a characteristic immediately before the start of the lane change is recognized.

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