JP2007125959A - Steering device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering device for a vehicle, capable of providing steering assist matching the intention of steering of a driver, and improving a steering feel. <P>SOLUTION: This steering device for a vehicle is provided with a controller 14 to control steering assist quantity in accordance with steering input by a driver. It is provided with a target course determining part 15 to recognize a target course along which an own vehicle is to travel. The controller 14 predicts steering input by the driver based on position relation between the target course and a travel course of the own vehicle, and controls the steering assist quantity based on the predicted steering input by the driver. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention belongs to the technical field of a vehicle steering apparatus that performs steering assistance in consideration of the driving behavior of a driver.

  2. Description of the Related Art Conventionally, a steering angle control device that recognizes the outside world, determines a target course on which the host vehicle travels, and automatically steers based on the relationship between the target course and the traveling state of the host vehicle is known. This technique performs steering control according to the driver's steering intervention level in order to switch from manual steering to automatic steering without a sense of incongruity (see, for example, Patent Document 1).

Further, in the electric power steering apparatus, when the driver's steering state is determined and it is determined that the steering state is maintained, the steering assist force gain is set to a value larger than the standard value, thereby A technique for reducing the steering burden is known (for example, see Patent Document 2).
JP-A-9-254803 JP 2004-268767 A

  However, in the former of the above prior arts, the reliability, dependency, preference, etc. of the driver for the automatic steering control system are diverse, so the driver is worried about the timing of the steering input and the deviation of the steering amount. There was a problem of giving a feeling of feeling and fatigue. In the latter case, the steering assist amount is determined according to the steering state of the driver, such as the steering angle and steering force. Therefore, the steering assist amount is insufficient at the initial stage of steering and minute steering, and a catch occurs at the time of switching back. Thus, there is a problem that the driver feels uncomfortable due to the delay in steering assistance.

  The present invention has been made paying attention to the above-described problem, and the object of the present invention is to realize both the steering assistance that matches the steering intention and the steering state of the driver and the improvement of the steering feeling. The object is to provide a vehicle steering system.

In order to achieve the above object, the present invention provides:
In a vehicle steering apparatus that controls a steering assist amount in accordance with a driver's steering input,
It is characterized in that a driver's steering input is predicted from a positional relationship between a target course that the host vehicle should travel and a traveling course of the host vehicle, and a steering assist amount is controlled based on the predicted driver's steering input.

  In the present invention, the steering assist amount is controlled based on the driver's steering input predicted from the positional relationship between the target course that the host vehicle should travel and the traveling course of the host vehicle. For example, if the amount of deviation (deviation) of the traveling course with respect to the target course is large, it is determined that the steering input for correction needs to be increased, and the direction and amount of steering assistance are calculated in advance. Before the steering input is generated, the steering assist assistance is actuated in advance. As a result, the steering burden is reduced without being delayed by the driver's steering input, and at the same time, a smooth feeling can be obtained at the start of the initial torque, thereby improving the steering feeling. Moreover, since the driver is free to drive the vehicle because of the steering assistance based on the steering assistance, there is no distrust or anxiety unlike the automatic steering control, and the mental burden can be reduced. As a result, it is possible to achieve both the steering assist that matches the driver's steering intention and the steering state and the improvement of the steering feeling.

  Hereinafter, the best mode for carrying out the present invention will be described based on Examples 1 to 5.

First, the configuration will be described.
FIG. 1 is an overall configuration diagram of a vehicle steering apparatus according to a first embodiment. As shown in FIG. 1, the vehicle steering apparatus of the first embodiment includes a steering handle 1, a steering shaft 2, a pinion 3, a rack shaft 4, a tie rod 5, a front wheel 6, a steering angle sensor 7, Steering torque sensor 8, vehicle speed sensor 9, yaw rate sensor 10, motor 11, speed reducer 12, motor rotation angle sensor 13, controller (steering control means) 14, target course determination unit (target course recognition) Means) 15.

  For example, the target course determination unit 15 recognizes a traveling lane, an obstacle, or the like using a camera, or detects a target course (for example, the center position of the white line) of the host vehicle using a GPS or a car navigation system. ,decide.

  The controller 14 controls the steering angle detected by the steering angle sensor 7, the steering torque detected by the steering torque sensor 8, the vehicle speed detected by the vehicle speed sensor 9, and the target course determination unit 15. A target steering assist amount is determined based on the target course of the vehicle, a target motor rotation angle corresponding to the target steering assist amount is set, and the motor rotation angle detected by the motor rotation angle sensor 13 is the target motor rotation angle. The motor 11 is servo-controlled so that

Next, the operation will be described.
[Steering assist control processing]
FIG. 2 is a system block diagram of the first embodiment. In FIG. 2, y is a current vehicle position, Ls is a forward gaze distance, φ is a yaw angle, and y ₀ is a target course.

  In step S1, the target course determination unit 15 detects and determines the target course of the host vehicle.

  In step S2, the steering angle sensor 7, the vehicle speed sensor 9, and the yaw rate sensor 10 detect the steering angle, the vehicle speed, and the vehicle yaw rate, and the controller 14 calculates the running state such as the vehicle slip angle and the vehicle running locus.

In step S3, the comparators 16a and 16b calculate a deviation between the target course and the actual course from the target course determined in step S1 and the actual traveling state of the host vehicle detected in step S2.
At this time, for example, as shown below, the calculation method of the deviation is varied according to the road curvature ρ of the traveling road.

(1) In the case of a state with a large curvature including turning (ρ> ρ ₀ ) The future position is predicted in an arc as the current vehicle position (x ₀ , y ₀ ) and the course angle v ₀ . That is, assuming that V is constant and v = v0 + v't, the deviation e from the target course (X ^* , Y ^* ) ahead in τ seconds is calculated based on the following equation (1) .

(2) When the target course is close to a straight line (ρ ≦ ρ ₀ ) Current lateral vehicle position y, current vehicle yaw angle φ (| φ | << 1), target at the forward gaze distance Ls As a course y _i , a future position is predicted temporarily, and a deviation e is obtained from the following equation (2).
e = y + Lsφ-y _i
Here, as shown in FIGS. 3 and 4, the front gaze distance Ls may be a function of the vehicle speed V and the steering speed θ ′, and the front gaze distance Ls may be variable according to the vehicle speed V and the steering speed θ ′.

なお、構築されるドライバモデル１７において、運転者の操舵タイミングや操舵量の個性を学習し、学習結果に基づいて運転者操舵特性を補正する構成としてもよい。 In step S4, the controller 14 constructs a driver model 17 that represents the characteristics of the driver's steering input (driver steering characteristics), and predicts the driver's steering input from the deviation e.
At this time, for example, it is assumed that the control operation that humans can continue for a long time without a heavy burden is the target operation calculated in step S3 on the assumption that the proportional operation including the dead time is added with very weak differentiation and integration operations. From the deviation e between the course and the actual course, the transfer characteristic to the driver steering input is set as follows.

Note that the driver model 17 to be constructed may be configured to learn the driver's steering timing and the individuality of the steering amount and correct the driver steering characteristics based on the learning result.

In step S5, the steering assist amount for the deviation e is determined in the gain block 18. For example, as shown in FIG. 5, the steering assist amount with respect to the deviation e is set to zero when the deviation e is zero, and is set to a large value in proportion to the deviation e, according to the proportional operation gain k ₁ .

In step S6, in the gain block 19, a steering assist amount for the deviation differential e ′ obtained by differentiating the deviation e is determined. For example, as shown in FIG. 6, the steering assist amount for the deviation derivative e ′ is zero when the deviation derivative e ′ is zero, and becomes larger as the deviation derivative e ′ is larger, according to the differential operation gain k _2. Set as follows.

In step S7, in the gain block 20, the steering assist amount for the deviation integral ∫e obtained by integrating the deviation e is determined. Steering assist amount for the deviation integral ∫e, for example, as shown in FIG. 7, in accordance with the integral operation gain k _3, deviation integral ∫e is the maximum value at zero, approaches zero larger the deviation integral ∫e Set to be a value.

  In step S8, in the adder 21, the steering assist amount corresponding to the driver's steering input predicted from the driver model 17 in step S4, (1) the steering assist amount for the deviation e, and (2) the steering for the deviation derivative e ′. The steering assist amount ((1) + (2) + (3) in FIG. 8) obtained by adding the assist amount and (3) the steering assist amount with respect to the deviation integral ∫e is added, and the final steering of the motor 11 is performed. Determine the amount of assistance.

[Steering assistance based on driver's steering prediction]
In the first embodiment, the target course detection unit 15 determines a target course for the host vehicle to travel, and travels the target course using the driver model 17 from the deviation e between the travel position after τ seconds and the target course. The steering input after τ seconds necessary for this is calculated, and steering assist is performed according to the calculation result, the deviation e, the deviation differential e ′, and the deviation integral ∫e.

  Thereby, before the driver's steering input does not occur, it is possible to actuate the steering assist assistance according to the deviation e, so that the steering burden is reduced without delaying the driver's steering input, The torque rise at the beginning of steering becomes smooth, and a smooth feeling can be obtained. In addition, unlike the steering angle amount control such as automatic steering control (for example, see Japanese Patent Application Laid-Open No. 9-254803), since the steering assist is based on the steering assist amount, the driver is free to drive the vehicle. There is no distrust or anxiety like automatic steering control.

  FIG. 9 is a time chart showing a time series change of the steering angle and the steering torque in the normal steering assist control and the steering assist control of the first embodiment. As shown in FIG. 9, in the first embodiment, before the steering angle is generated. That is, the auxiliary torque rises before the start of steering by a human (driver), and steering assistance is performed by the generation of faster auxiliary torque.

[Calculation of deviation e according to road curvature ρ]
In the first embodiment, when the road curvature ρ is larger than the predetermined curvature ρ ₀ , the deviation e is calculated based on the equation (1). When the road curvature ρ is equal to or less than the predetermined curvature ρ ₀ , the equation (2 ) To calculate the deviation e. In other words, when the host vehicle is traveling on a curve, the host vehicle is turning, and when the host vehicle is traveling on a straight path, it can be estimated that the host vehicle is traveling straight. The future position can be predicted in a circular arc, and if the host vehicle is traveling straight ahead, the future position can be predicted temporarily, so that a more accurate deviation e can be obtained. As a result, the prediction accuracy of the driver's steering input can be improved.

  Further, in the expression (2), the front gaze distance Ls is set to a larger value as the vehicle speed V and the steering speed θ ′ are higher. That is, as the vehicle speed V and the steering speed θ ′ become higher, the driver's field of view becomes narrower and the forward gaze distance Ls becomes longer (far). Therefore, the front gaze distance Ls is increased according to the vehicle speed V and the steering speed θ ′. By setting the value, regardless of the vehicle speed V and the steering speed θ ′, it is possible to improve the prediction accuracy of the driver's steering input when traveling straight ahead.

[Operation of calculating steering assist amount according to deviation e]
In the first embodiment, the steering assist amount is increased as the deviation e (absolute value) increases. In other words, the greater the deviation of the travel course from the target course, the more the driver needs to make a steering input for correction. Therefore, the greater the deviation e, the larger the steering assist amount. Regardless of the amount, the steering burden can be reduced.

[Operation of calculating the steering assist amount according to the deviation derivative e ']
In the first embodiment, the steering assist amount is increased as the deviation derivative e ′ (absolute value thereof) increases. In other words, the higher the increase rate of the deviation of the traveling course from the target course, the faster the driver needs for steering input for correction. Therefore, the larger the differential derivative e ′, the larger the steering assist amount. Steering assistance without delay can be realized with respect to the initial rise of the steering torque.

[Operation of calculating steering assist amount according to deviation integral ∫e]
In the first embodiment, the steering assist amount is made closer to zero as the deviation integral ∫e is larger. For example, if the steering assist amount is constant relative to the deviation integral ∫e or the steering assist amount is increased as the deviation integral ∫e is larger, especially when the deviation e between the target course and the traveling course is large, the overintegration overshoot Shooting may occur. Therefore, the larger the deviation integral ∫e is, the more the steering assist amount is converged to zero, whereby the overintegration can be suppressed and the convergence can be improved.

Next, the effect will be described.
The vehicle steering apparatus according to the first embodiment has the following effects.

  (1) A vehicle steering apparatus including a controller 14 that controls a steering assist amount in accordance with a steering input of a driver includes a target course determination unit 15 that recognizes a target course that the host vehicle should travel, and includes a control controller 14 predicts the driver's steering input from the positional relationship between the target course and the traveling course of the host vehicle, and controls the steering assist amount based on the predicted driver's steering input. Therefore, it is possible to achieve both the steering assistance that matches the driver's steering intention and the steering state and the improvement of the steering feeling.

(2) When the road curvature ρ is larger than the predetermined curvature ρ ₀ , the controller 14 determines the deviation e between the target course (X ^* , Y ^* ) and the traveling course (x, y) after τ seconds, The calculation is made based on the equation (1), and the driver's steering input is predicted based on the deviation e. That is, when the vehicle is traveling on a curve having a relatively large road curvature ρ, the deviation e is calculated from the arc-predicted traveling course, thereby improving the prediction accuracy of the driver's steering input during the curve traveling. be able to.

(3) When the road curvature ρ is equal to or less than the predetermined curvature ρ ₀ , the controller 14 determines the current lateral vehicle position y, the current vehicle yaw angle φ (| φ | << 1), and the forward gaze distance Ls. When the previous target course y _i is set, the deviation e between the target course and the traveling course is calculated based on the equation (2), and the driver's steering input is predicted based on the deviation e. In other words, when driving on a road that is relatively close to a straight line, the prediction accuracy of the driver's steering input during straight driving is improved by primarily predicting the future position (travel course) of the vehicle. Can be made.

  (4) Since the controller 14 varies the forward gaze distance Ls based on the vehicle speed V and the steering speed θ ′, the driver's steering input during straight traveling is performed regardless of the vehicle speed V and the steering speed θ ′. Prediction accuracy can be improved.

  (5) Since the controller 14 includes the driver model 17 that inputs the deviation e between the target course and the traveling course and estimates the driver's steering input based on the driver steering characteristics set in advance, Steering assistance that matches the driving sense of the person can be realized.

  (6) Since the controller 14 increases the steering assist amount as the absolute value of the deviation e increases, the steering burden can be reduced regardless of the driver's corrected steering amount.

  (7) Since the control controller 14 increases the steering assist amount as the absolute value of the differential value e ′ of the deviation e increases, it is possible to realize steering assist without delay with respect to the rise of the steering torque in the initial stage of the corrected steering.

  (8) As the integral value ∫e of the deviation e is larger, the controller 14 brings the steering assist amount closer to zero, so that overshoot due to overintegration can be suppressed and convergence can be improved.

  The second embodiment is an example of steering assist control at the time of additional steering. Since the overall configuration is the same as that of the first embodiment, illustration and description are omitted.

  When the driver's initial steering input does not reach the driver model calculated value (predicted steering input) and the steering needs to be steered, the controller 14 of the second embodiment provides steering assistance based on the driver model calculated value in advance. Do.

Further, the controller 14 determines that the driver's initial steering input has reached the driver model calculation value, but if the driver intentionally increases steering and requires steering, the steering assist after determining that the driver has increased Set the amount gain to a higher value than normal. In the second embodiment, when the steering amount T is within a range of T ± α (α is a predetermined value having a small absolute value) and T _d (T _d > T) is reached after a certain time t ₁ , it is determined that the increase is made. Adopt the method to do.

Next, the operation will be described.
[Steering assist when adding more]
FIG. 10 is a time chart showing the time-series change of the steering angle and the steering torque when the driver's initial steering input does not reach the driver model calculation value and the steering is required. In the second embodiment, steering assist is performed based on the driver model calculation value at the time of initial steering after the increase determination is made.

  As a result, for example, when performing turning steering with a high road curvature ρ, it is appropriate before the driver's additional steering in a situation where the vehicle cannot fully turn at the initial steering input angle due to insufficient experience of the driver, etc. Steering assistance is possible, and prompt steering assistance is possible. In particular, it is possible to reduce the steering burden and the uncomfortable feeling at the time of additional turning.

  FIG. 11 is a time chart showing the time-series change of the steering angle and the steering torque when the driver's initial steering input has reached the driver model calculation value but the driver intentionally increases the steering angle. It is. In the second embodiment, the gain of the steering assist amount after the increase determination is set to a value higher than normal.

  This makes it possible to provide appropriate steering assistance before the driver's emergency avoidance steering, for example, in situations where sudden avoidance steering is required, such as sudden jumps or interruptions on the target course. The steering burden during steering can be reduced.

Next, the effect will be described.
The vehicle steering apparatus according to the second embodiment has the following effects in addition to the effects (1) to (8) of the first embodiment.

  (9) When the driver's initial steering input does not reach the predicted driver's steering input, the control controller 14 determines that the additional steering or the return steering is necessary before the initial steering. The steering assist amount is controlled based on the predicted driver steering input. Therefore, appropriate steering assistance can be performed before the driver increases the steering angle, and the steering burden at the time of the additional rotation can be reduced.

  (10) When the driver's initial steering input matches the predicted driver's steering input, the control controller 14 increases the steering assist gain more than the initial steering when the additional steering is performed. Since the value is set to a high value, it is possible to reduce the steering burden on the driver during emergency avoidance steering.

  The third embodiment is an example of steering assist control at the time of switchback steering. Since the overall configuration is the same as that of the first embodiment, illustration and description are omitted.

  When the driver's initial steering input exceeds the driver model calculation value (predicted steering input) and switchback steering is required, the control controller 14 according to the third embodiment performs steering assistance based on the driver model calculation value in advance. .

Further, the controller 14 determines that the driver's initial steering input has reached the driver model calculation value. However, if the driver intentionally requires switchback steering, the steering assist after the determination of switchback is made. Set the amount gain to a higher value than normal. Here, as a determination method of the switchback, when the steering amount T is in the range of T ± α (α is a predetermined value having a small absolute value), T _l (T _l <T) is obtained after continuing for a certain time t ₁ . Time is considered.

Next, the operation will be described.
[Steering assist when switching back]
FIG. 12 is a time chart showing time-series changes in the steering angle and the steering torque when the driver's initial steering input exceeds the driver model calculation value and the switchback steering is required. In the third embodiment, after the switchback is determined, steering assistance based on the driver model calculation value at the time of initial steering is performed.

  Thus, for example, in a situation where the vehicle turns too much at the initial input angle due to lack of experience of the driver or a difference in sensitivity due to the vehicle in the case of a turning operation with a high curvature or right / left turn, etc. Appropriate steering assistance is possible before the switchback steering, and prompt steering assistance is possible. In particular, it is possible to suppress over-cutting, reduce the steering burden at the time of switching back, and the uncomfortable feeling of steering.

  FIG. 13 shows the time when the driver's initial steering input coincides with the driver model calculation value, but the driver intentionally requires the switchback steering to show the time-series change of the steering angle and the steering torque. It is a chart. In the third embodiment, the gain of the steering assist amount after the switch-back determination is set to a value higher than that in the normal state.

  This makes it possible to provide appropriate steering assistance before the driver's emergency avoidance steering, for example, in situations where sudden avoidance steering is required, such as sudden jumps or interruptions on the target course. The steering burden during steering can be reduced.

Next, the effect will be described.
The vehicle steering apparatus of the third embodiment has the following effects in addition to the effects (1) to (8) of the first embodiment and the effects (9) and (10) of the second embodiment.

  (11) When the controller 14 determines that the switchback steering is necessary when the driver's initial steering input does not match the predicted driver's steering input, the controller 14 predicts the driving predicted before the initial steering. The steering assist amount is controlled based on the steering input of the person. Therefore, appropriate steering assistance is possible before the driver switches back, and the steering burden at the time of switch back can be reduced.

  (12) When the driver's initial steering input matches the predicted driver's steering input when the driver's initial steering input coincides with the predicted steering input, the control controller 14 increases the steering assist gain more than the initial steering. Since the value is set to a high value, it is possible to reduce the steering burden on the driver during emergency avoidance steering.

  The fourth embodiment is an example of steering assist control in a case where transient switchback steering is performed in a scene where the steering speed is high. Since the overall configuration is the same as that of the first embodiment, illustration and description are omitted.

The controller 14 of the fourth embodiment adds a steering assist amount in a direction in which steering is hindered when switching back instantaneously (transiently) in a scene where the steering speed θ ′ is equal to or greater than the predetermined value θ ₀ (transient) ( Reverse assist). FIG. 14 is a reverse assist addition amount map. In Example 4, the reverse assist addition amount is increased as the steering speed θ ′ is higher.

Next, the operation will be described.
[Steering assistance during transitional switching]
FIG. 15 is a time chart showing a time-series change in the steering angle and the steering torque when the driver performs quick steering while switching back instantaneously. At this time, in Example 4, the steering assistance is instantaneously performed in the direction opposite to the steering direction, and then the steering assistance is performed with a gain higher than usual.

  This makes it possible, for example, to stop suddenly when changing lanes during steering, or when sudden turn-off is required to avoid sudden occurrences such as sudden jumps or interruptions on the target course. Both quick steering assistance at the time of return and reduction of the uncomfortable feeling of steering can be realized.

Next, the effect will be described.
In the vehicle steering system of the fourth embodiment, the effects (1) to (8) of the first embodiment, the effects (9) and (10) of the second embodiment, and the effects (11) and (12 of the third embodiment. In addition, the following effects can be obtained.

  (13) When the steering speed is higher than the predetermined value and the driver performs a transient switchback steering, the controller 14 increases the steering assist amount in a direction that prevents the switchback steering. For this reason, it is possible to realize both quick steering assistance at the time of sudden switchback and reduction of the uncomfortable feeling in situations where switchback for avoidance suddenly becomes necessary.

  The fifth embodiment is an example in which the steering assist amount is determined based on the steering assist amount corresponding to the feed forward (F / F) gain and the steering assist amount corresponding to the feedback (F / B) gain. Since the overall configuration is the same as that of the first embodiment, illustration and description are omitted.

  In the fifth embodiment, the F / F steering assist amount is calculated by multiplying the steering input of the driver necessary for obtaining the target course by the F / F gain, and the F / F is calculated with respect to the deviation between the target course and the traveling course. Multiply the B gain to calculate the F / B steering assist amount, and add both steering assist amounts to assist the driver in steering. At this time, the weighting of the F / F gain and the F / B gain is changed according to the deviation e between the target course and the traveling course.

Next, the operation will be described.
[Steering assist control processing]
FIG. 16 is a system block diagram of the fifth embodiment.
In step S11, the target course determination unit 15 detects and determines the target course of the host vehicle.

In step S12, the controller 14 constructs a driver model 22 representing the driver's steering input characteristics (driver steering characteristics), estimates the driver's steering input necessary to obtain the target course, and estimates The F / F steering assist amount is calculated by multiplying the steering input by the F / F gain. Here, F / F gain, as shown in FIG. 17, large as the absolute value of the deviation e is set to the minimum value when less than the predetermined value e _0, the deviation e is large when exceeding a predetermined value e ₀ Set to be a value.

In step S13, the gain block 23 calculates the F / B steering assist amount obtained by multiplying the deviation e between the target course and the traveling course by the F / B gain. Here, as shown in FIG. 17, the F / B gain is the maximum value when the absolute value of the deviation e is equal to or less than a predetermined value e ₀ , and the F / B gain is smaller as the deviation e increases when the absolute value exceeds the predetermined value e _0. Set to be a value.

  In step S14, the steering assist amount calculation block 24 adds the F / F steering assist amount calculated in step S12 and the F / B steering assist amount calculated in step S13 to determine the steering assist amount.

[Weighting action according to deviation e]
In the fifth embodiment, as shown in FIG. 17, when the deviation e between the target course and the traveling course is large (e> e ₀ ), the F / F gain is increased and the deviation e is small (e ≦ e ₀ ). Increase the F / B gain. Thereby, it is possible to support the driver's recognition of the outside world, and to eliminate the timing delay of adding the steering assist amount. Furthermore, by adjusting the weighting of the F / F gain and the F / B gain according to the deviation e, more natural steering assistance according to the scene can be realized.

Next, the effect will be described.
In the vehicle steering system of the fifth embodiment, the following effects can be obtained in addition to the effect (1) of the first embodiment.

  (14) The control controller 14 is provided with a driver model 22 that inputs a target course and estimates a driver's steering input necessary for traveling on the target course based on preset driver steering characteristics. F / F steering assist amount obtained by multiplying the driver's steering input by the F / F gain, and F / B steering assist amount obtained by multiplying the deviation e of the positional relationship between the target course and the traveling course by the F / B gain. Is added to determine the steering assist amount.When the deviation e is large, the F / F gain weight is set larger than the F / B gain weight. When the deviation e is small, the F / B gain weight is set to F. / F Gain larger than the gain weight. Therefore, it is possible to support the driver's recognition of the outside world, to eliminate the timing delay of adding the steering assist amount, and to realize more natural steering assist according to the scene.

(Other examples)
As mentioned above, although the best form which implements the steering device for vehicles of the present invention has been explained based on Examples 1-5, the concrete composition of the present invention is not limited to Examples 1-5. Even if there is a design change or the like without departing from the gist of the invention, it is included in the present invention.

For example, in the first to fifth embodiments, it goes without saying that a dead zone is provided in each detection means (sensor) and a limiter is provided in the output value.
In the fifth embodiment, an example in which both the feedforward gain and the feedback gain are linear characteristics has been described. However, nonlinear characteristics may be used.

1 is an overall configuration diagram of a vehicle steering apparatus according to a first embodiment. 1 is a system block diagram of Embodiment 1. FIG. It is a front gaze distance characteristic figure with respect to vehicle speed. It is a front gaze distance characteristic figure with respect to steering speed. It is a proportional operation gain setting map. It is a differential operation gain setting map. It is an integral operation gain setting map. It is a steering assistance amount setting map. 3 is a time chart showing a time-series change of a steering angle and a steering torque in normal steering assist control and steering assist control in Embodiment 1; 6 is a time chart showing time-series changes in steering angle and steering torque when the driver's initial steering input does not reach the driver model calculation value and requires steering. 7 is a time chart showing time-series changes in steering angle and steering torque when the driver's initial steering input has reached the driver model calculation value, but the driver intentionally increases the steering angle. 6 is a time chart showing a time-series change in steering angle and steering torque when the driver's initial steering input exceeds the driver model calculation value and switchback steering is required. 7 is a time chart showing a time-series change of a steering angle and a steering torque when the driver's initial steering input coincides with the driver model calculation value, but the driver intentionally requires the switchback steering. 10 is a reverse assist addition amount setting map according to a fourth embodiment. It is a time chart which shows the time-sequential change of a steering angle and a steering torque at the time of switching back instantaneously when the driver | operator is performing quick steering. FIG. 10 is a system block diagram of Embodiment 5. 10 is an F / F gain / F / B gain setting map according to the fifth embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steering handle 2 Steering shaft 3 Pinion 4 Rack shaft 5 Tie rod 6 Front wheel 7 Steering angle sensor 8 Steering torque sensor 9 Vehicle speed sensor 10 Yaw rate sensor 11 Motor 12 Decelerator 13 Motor rotation angle sensor 14 Control controller (steering control means)
15 Target course decision section (Target course recognition means)

Claims (13)

In a vehicle steering apparatus provided with a steering control means for controlling a steering assist amount in accordance with a driver's steering input,
It has a target course recognition means for recognizing a target course that the host vehicle should travel,
The steering control means predicts a driver's steering input from a positional relationship between the target course and a traveling course of the host vehicle, and controls a steering assist amount based on the predicted driver's steering input. Vehicle steering system. The vehicle steering apparatus according to claim 1,
When the road curvature ρ is larger than the predetermined curvature ρ ₀ , the steering control means determines that the current vehicle position (x ₀ , y ₀ ), the target course (X ^* , Y ^* ), and the traveling course (x, y) When the course angle v ₀ , the vehicle speed V is constant, and the course angle v after v seconds is v = v ₀ + v't, the target course (X ^* , Y ^* ) and running course (x, y after τ seconds) ) With the following equation:

The vehicle steering apparatus is characterized in that the steering input of the driver is predicted based on the deviation e. The vehicle steering apparatus according to claim 1 or 2,
When the road curvature ρ is equal to or less than the predetermined curvature ρ ₀ , the steering control means uses the current lateral vehicle position y, the current vehicle yaw angle φ (| φ | << 1), and the forward gaze distance Ls ahead. When the target course y _i is the deviation e between the target course and the traveling course, the following equation:
e = y + Lsφ-y _i
The vehicle steering apparatus is characterized in that the steering input of the driver is predicted based on the deviation e. The vehicle steering apparatus according to claim 3,
The steering control device varies the forward gaze distance Ls based on at least one of a vehicle speed and a steering speed. The vehicle steering apparatus according to any one of claims 1 to 4, wherein:
The steering control means includes a driver model that inputs a deviation between the target course and the traveling course and estimates a driver's steering input based on a driver steering characteristic set in advance. Steering device. The vehicle steering apparatus according to claim 5,
The vehicle steering apparatus, wherein the steering control means increases the steering assist amount as the absolute value of the deviation is larger. The vehicle steering device according to any one of claims 5 and 6,
The vehicle steering apparatus, wherein the steering control means increases the steering assist amount as the absolute value of the differential value of the deviation increases. The vehicle steering apparatus according to any one of claims 5 to 7,
The vehicle steering apparatus according to claim 1, wherein the steering control means brings the steering assist amount closer to zero as the integral value of the deviation is larger. The vehicle steering apparatus according to any one of claims 1 to 8,
The steering control means predicts before the initial steering when it determines that the additional steering or the return steering is necessary when the initial steering input of the driver does not coincide with the predicted steering input of the driver. A steering apparatus for a vehicle, wherein the steering assist amount is controlled based on the steering input of the driver. The vehicle steering apparatus according to any one of claims 1 to 9,
When the driver's initial steering input matches the predicted driver's steering input, the steering control means increases the steering assist gain more than at the time of initial steering when the steering is increased or switched back. A vehicle steering apparatus characterized in that it is set to a higher value. The vehicle steering apparatus according to any one of claims 1 to 10, wherein:
The steering control means adds a steering assist amount in a direction that prevents the switchback steering when the driver performs a transient switchback steering when the steering speed is higher than a predetermined value. A vehicle steering apparatus characterized by the above. The vehicle steering apparatus according to claim 1,
The steering control means includes
A driver model that inputs the target course and estimates a driver's steering input necessary to travel the target course based on a driver steering characteristic set in advance;
F / F steering assist amount obtained by multiplying the estimated driver's steering input by a feed forward (F / F) gain, and a feedback (F / B) with respect to a positional relationship deviation between the target course and the traveling course ) Add the F / B steering assist amount multiplied by the gain to determine the steering assist amount,
When the deviation is large, the F / F gain weight is larger than the F / B gain weight, and when the deviation is small, the F / B gain weight is larger than the F / F gain weight. A vehicle steering system. In a vehicle steering apparatus that controls a steering assist amount in accordance with a driver's steering input,
A vehicle that predicts a driver's steering input from a positional relationship between a target course that the host vehicle should travel and a traveling course of the host vehicle, and controls a steering assist amount based on the predicted driver's steering input. Steering device.

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