JP4100222B2 - Vehicle steering control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a vehicle steering by a so-called steer-by-wire system in which an operation unit operated by a driver and a steering unit that steers steered wheels can be operated without mechanical coupling. It belongs to the technical field of control devices.
[0002]
[Prior art]
Conventionally, a vehicle steering control device that can variably control a gear ratio (a ratio of a steering angle change of a steered wheel to a steering angle change of a steering wheel of an operation unit) and a steering reaction force has a variable gear ratio. The steering reaction force is increased when the turning speed at which the actuator does not follow is large or when the difference between the target rudder angle and the actual rudder angle is large (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
JP-A-10-324261 (FIGS. 3 and 6).
[0004]
[Problems to be solved by the invention]
Conventionally, to reduce the steering load of the driver, to reduce the steering amount when turning at low speed (reduce the gear ratio), to reduce the steering amount of the tire relative to the steering wheel steering amount to increase the stability at high speed Since it is effective to do this (increase the gear ratio), the gear ratio is made variable.
[0005]
However, in the conventional vehicle steering control device, since the steering actuator cannot follow fast steering, the countermeasure is to increase the steering reaction force in order to reduce the steering speed. Even in this case, the steering angle and the steering reaction force differ depending on the steering speed, and the driver may feel uncomfortable.
[0006]
In addition, in a vehicle equipped with a variable gear ratio mechanism so far, the steering angle is smaller than that of a normal vehicle without a variable gear ratio mechanism, for example, in a F1 racing car. Such a vehicle that can be driven at a steering angle that does not need to be changed is not realized. On the other hand, it is said that the driver's steering load can be further reduced if there is no need to carry it over.
[0007]
In particular, the steering angle of the steering wheel that can be operated without switching is used because the steering angle up to a point close to full steering, such as garage entry or U-turn, is used at low speeds. There is a problem that it is difficult to adjust the vehicle track.
[0008]
The present invention has been made paying attention to the above problem, and an object of the present invention is to provide a vehicle steering control device that can easily perform vehicle trajectory correction steering while reducing steering discomfort to the driver. .
[0009]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention,
A gear ratio setting means for setting scan Tearing change the steering wheel steering angle of the steering angle of the wheel (θ) (δ) gear ratio is the ratio of the change in the (Δθ / Δδ),
And turning control means for driving the rolling steering actuator to be at least the set gear ratio (Δθ / Δδ) and steering angle (theta) and the target turning angle calculated based on ([delta] ^*),
In car dual steering control apparatus provided with,
A steering reaction force actuator for generating a steering reaction force torque (T) on the steering wheel, and a target steering reaction force calculation means for calculating a target steering reaction force torque (T ^* ) to the steering reaction force actuator ,
The gear ratio setting means sets a gear ratio characteristic in which the gear ratio (Δθ / Δδ) decreases while the gear ratio (Δθ / Δδ) has a constant region as the steering angle absolute value | θ | And
The target steering reaction force calculation means is based on the gear ratio (Δθ / Δδ) set by the gear ratio setting means, and the steering reaction force with respect to a change in steering angle as the gear ratio (Δθ / Δδ) decreases. The target steering reaction torque (T ^* ) is calculated so that a steering reaction torque ratio (ΔT / Δθ), which is a torque change ratio, is increased .
[0010]
【The invention's effect】
Therefore, in the vehicle steering control device according to the present invention, the gear discomfort is reduced gradually or stepwise according to the steering angle of the steering wheel, thereby reducing the driver's uncomfortable feeling of steering. However, the trajectory correction steering of the vehicle can be easily performed.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for realizing a vehicle steering control device of the present invention will be described based on first to fourth embodiments shown in the drawings.
[0012]
(First embodiment)
First, the configuration will be described.
FIG. 1 is an overall system diagram showing a vehicle steering control apparatus according to a first embodiment. In FIG. 1, 1 is a steering wheel, 2 is a steering reaction force actuator, 3 is a torque sensor, 4 is a steering angle sensor, 5 is a steering wheel, 6 is a transmission unit, 7 is a steering gear (steering device), 8 is A steering actuator, 9 is a steering angle sensor, 10 is a steering angle controller (steering control means), 11 is a vehicle speed sensor, and 12 is a yaw rate sensor.
[0013]
The operation unit of the first embodiment device includes a steering wheel 1 that transmits the operation of the driver of the vehicle, a steering reaction force actuator 2 that generates a steering reaction force on the steering wheel 1, and a steering wheel 1 and a steering reaction force actuator 2. And a steering angle sensor 4 for measuring the steering angle θ at which the steering wheel 1 is operated.
[0014]
The steered portion of the first embodiment apparatus includes steered wheels 5 and 5 for steering the vehicle, a transmission unit 6 for transmitting the steering force to the steered wheels 5 and 5, and the vehicle In order to steer the vehicle, a steering gear 7 that transmits a force in the lateral direction of the vehicle, and a steering actuator 8 that operates the steering gear 7 to generate a force to steer the vehicle.
[0015]
The steering angle control system of the first embodiment apparatus is configured to determine the steering angle sensor δ of the steering wheels 5 and 5 and the torque sensor 3 that measures the steering reaction torque T, the steering angle sensor 4 that measures the steering angle θ, and the steering wheel 5. A steering angle controller 9 for calculating a steering angle sensor 9 to be measured, a control amount for causing the steered wheels 5 and 5 to generate a steering angle δ, and a control amount for causing the steering reaction force actuator 2 to generate a steering reaction force 10, a vehicle speed sensor 11 that measures the vehicle speed V of the vehicle, and a yaw rate sensor 12 that measures the yaw rate ψ ′ of the vehicle.
[0016]
FIG. 2 is a block diagram showing the steering angle control system of the first embodiment apparatus. In the steering angle controller 10, a gear ratio setting unit 10a (gear ratio setting means) and a target steering reaction force calculation unit 10b (target steering) are shown. Reaction force calculation means) and a target turning angle calculation unit 10c are set. Is configured.
[0017]
The gear ratio setting unit 10a sets a gear ratio Δθ / Δδ, which is a ratio between the steering angle change Δθ of the steering wheel 1 and the steering angle change Δδ of the steered wheels 5, 5.
[0018]
The gear ratio setting unit 10a is set with a gear ratio characteristic B in which the gear ratio Δθ / Δδ decreases as the steering angle absolute value | θ | increases, while the gear ratio Δθ / Δδ decreases. Yes.
[0019]
That is, as shown in FIG. 4, the gear ratio setting unit 10 a of the first embodiment has a relationship between the steering angle δ of the steered wheels 5 and 5 with respect to the steering angle θ of the steering wheel 1.
(i) When the steering angle absolute value | θ | is about 40 ° (= θ1), the turning angle absolute value | δ | is about 5 °.
(ii) Steering angle absolute value | θ | is approximately 90 ° (= θ2) and turning angle absolute value | δ | is approximately 20 °.
(iii) Steering angle absolute value | θ | is approximately 140 ° (= θ3) and turning angle absolute value | δ |
And the gear ratio Δθ / Δδ is constant in each section in the three sections (i) 0 to θ1, (ii) θ1 to θ2, and (iii) θ2 to θ3. Characteristic B is set.
[0020]
That is, by replacing the relationship between the gear ratio to the steering angle θ γ (= Δθ / Δδ) , as shown in the B characteristic of FIG. 6, for example, (i) a gear ratio gamma = 8.0 approximately at 0~θ1 interval, ( ii) The gear ratio γ is about 3.3 in the section of θ1 to θ2, and (iii) the gear ratio γ is about 2.0 in the section of θ2 to θ3 steering.
[0021]
The target steering reaction force calculation unit 10b is based on the steering angle θ of the steering wheel 1 and the gear ratio Δθ / Δδ set by the gear ratio setting unit 10a, and as the gear ratio Δθ / Δδ decreases, The target steering reaction torque T ^* is calculated such that the steering reaction torque ratio ΔT / Δθ, which is the ratio of the steering reaction torque change to the steering angle change, increases. The target steering reaction force calculation unit 10b inputs the steering reaction force torque T from the torque sensor 3 as feedback information.
[0022]
The target turning angle calculation unit 10c is based on the steering angle θ of the steering wheel 1 and the gear ratio characteristic B from the gear ratio setting unit 10a, and the target turning angle δ serving as a command value for the turning actuator 8. ^* Is calculated. The target turning angle calculation unit 10c inputs the turning angle δ from the turning angle sensor 9 as feedback information.
[0023]
With the above configuration, it is possible to realize a so-called steer-by-wire function that can arbitrarily change the gear ratio characteristic that is the ratio of the steering angle change Δδ to the steering angle change Δθ by the driver input.
[0024]
Next, the operation will be described.
[0025]
[Steering control action for steering]
FIG. 3 shows the relationship between the steering wheel steering angle θ and the tire turning angle δ in the case of a normal vehicle.
[0026]
In the case of a normal vehicle, as shown in the gear ratio characteristic A of FIGS. 3 and 6, the gear ratio has a constant characteristic in the region from the neutral position to the predetermined steering angle before the lock position, and from the predetermined steering angle. The gear ratio is smoothly reduced up to the lock position. Although the turning inner wheel side and the outer wheel side are different, the full turning angle δL is about 35 °, the steering wheel lock angle θL is about 300 °, and the gear ratio (Δθ / Δδ) near neutral is about 18. is there.
[0027]
As described above, in the case of a normal vehicle, the steering wheel lock angle θL is about ± 300 °, so that in a low speed range that uses a rudder angle close to full steering such as garage entry or U-turn, It is necessary to change the steering wheel, which is a steering load for the driver.
[0028]
Therefore, by changing the steering wheel lock angle θL from ± 300 ° to about ± 140 °, which can be operated without changing by design change, the gain of the tire turning angle for the entire steering angle increases, and the vehicle track is corrected. This causes a problem that steering adjustment is difficult.
[0029]
On the other hand, the gear ratio characteristic B by the broken line in FIG. 4 is a relational characteristic between the steering angle θ of the steering wheel 1 and the steering angle δ of the steered wheels 5 and 5 in the first embodiment. The gear ratio characteristic B based on the straight line is a relational characteristic between the steering angle θ of the steering wheel 1 and the gear ratio γ (= Δθ / Δδ) in the first embodiment.
[0030]
In the section (i) in which the steering angle θ is 0 to θ1, the gear ratio Δθ / Δδ is set to be large so that the steered angle of the steered wheels 5 and 5 does not change so much even if the steering wheel 1 is greatly operated. . Since this area is sometimes used for fine adjustment of the course when passing on a narrow road, the gear ratio is increased, and the relationship between the steering angle θ and the turning angle δ is made linear. It becomes easier to perform corrective steering. For example, θ1 may be set to 40 deg and Δ1 may be set to about 5 deg depending on vehicle specifications.
[0031]
In the section (ii) in which the steering angle is θ1 to θ2, the turning angle δ2 is set to a turning angle necessary when turning right and left at the intersection, and the steering angle θ2 at that time is set to about 90 deg. The steering angle δ2 is about 20 deg. The gear ratio of the steering angles θ1 to θ2 is smaller than the gear ratio in the section (i) of the steering angles 0 to θ1.
[0032]
In the section (iii) where the steering angle is θ2 to θ3, the steering angle θ3 is a lock position. If the steering angle is set to about 140 deg, the steering wheel 1 can be operated without changing. The gear ratio at the steering angles θ2 to θ3 is further smaller than the section (ii) of the steering angles θ1 to θ2. In the region where the steering angle is θ2 to θ3, the steering angle is a region used when changing the direction or entering the garage. A large steering angle is required, but correction steering is also frequently performed. Since the change of the steering angle δ with respect to the steering angle θ is large, the correction steering becomes easier than the case of making the relationship non-linear by making the relationship between the steering angle θ and the steering angle δ linear.
[0033]
Next, the effect will be described.
In the vehicle steering control device of the first embodiment, the effects listed below can be obtained.
[0034]
(1) A steering wheel 1 that is not mechanically connected to the steering gear 7 of the steered wheels 5, 5, a steering actuator 8 that applies its output to the steering gear 7, and a steering angle θ of the steering wheel 1. A gear ratio setting unit 10a for setting a gear ratio Δθ / Δδ, which is a ratio between the change and the change in the turning angle δ of the steered wheels 5, 5, and at least the set gear ratio Δθ / Δδ and the steering angle θ. And a steering angle controller 10 that drives the steered actuator 8 so that the target steered angle δ ^* calculated based on the steering angle controller 10 is calculated. As the value | θ | becomes larger, the gear ratio characteristic B is set so that the gear ratio Δθ / Δδ becomes smaller while having a region where the gear ratio Δθ / Δδ becomes constant, so that the steering reaction force torque is increased. Vs driver That while reducing the steering discomfort, the trajectory correction steering of the vehicle can be easily performed.
[0035]
(2) The gear ratio setting unit 10a has a relationship between the steering angle δ of the steered wheels 5 and 5 with respect to the steering angle θ of the steering wheel 1,
(i) When the steering angle absolute value | θ | is about 40 ° (= θ1), the turning angle absolute value | δ | is about 5 °.
(ii) Steering angle absolute value | θ | is approximately 90 ° (= θ2) and turning angle absolute value | δ | is approximately 20 °.
(iii) Steering angle absolute value | θ | is approximately 140 ° (= θ3) and turning angle absolute value | δ |
Because of the gear ratio characteristic B, it is easy to fine-tune the course when passing on narrow roads, easy to turn left and right at the intersection, and full turning operability without changing the steering wheel 1 And can be achieved together.
[0036]
(3) The gear ratio setting unit 10a is configured so that the steering angle θ of the steered wheels 5 and 5 with respect to the steering angle θ of the steering wheel 1 is (i) 0 to θ1, (ii) θ1 to θ2, (iii) Since the gear ratio Δθ / Δδ has a constant gear ratio B in each of the three sections θ2 to θ3, the relationship between the steering angle θ and the turning angle δ is made nonlinear. Compared to the case, the correction steering becomes easier in the fine adjustment correction steering region and the full steering region of the course.
[0037]
(Second embodiment)
The second embodiment is an example in which the gear ratio change is smoothly connected to the gear ratio characteristic B of the first embodiment in the section (ii) between the section ( i) and the section (iii). is there.
[0038]
That is, as shown in FIG. 5, the gear ratio setting unit 10 a of the second embodiment has a relationship between the steering angle δ of the steered wheels 5 and 5 with respect to the steering angle θ of the steering wheel 1.
(i) When the steering angle absolute value | θ | is about 40 ° (= θ1), the turning angle absolute value | δ | is about 5 °.
(ii) Steering angle absolute value | θ | is approximately 90 ° (= θ2) and turning angle absolute value | δ | is approximately 20 °.
(iii) Steering angle absolute value | θ | is approximately 140 ° (= θ3) and turning angle absolute value | δ |
And the steering angle θ is (i) 0 to θ1, (ii) θ1 to θ2, and (iii) θ2 to θ3, the gear ratio Δθ / Δδ is the interval (i) and the interval (iii) In section (ii) , a gear ratio characteristic C is set in which the relationship between the steering angle (θ) and the turning angle (δ ) is smoothly connected to section (i) and section (iii) .
[0039]
That is, by replacing the relationship between the gear ratio to the steering angle θ γ (= Δθ / Δδ) , as shown in the C characteristic of FIG. 6, for example, (i) a gear ratio gamma = 8.0 approximately at 0~θ1 interval, ( ii) The gear ratio γ smoothly changes from about 8.0 to about 2.0 in the section of θ1 to θ2, and (iii) the gear ratio γ = 2.0 is given stepwise in the section of θ2 to θ3 steering.
[0040]
Since other configurations are the same as those of the first embodiment, illustration and description thereof are omitted.
[0041]
Next, the operation will be described.
[0042]
[Steering control action for steering]
In the section (i) in which the steering angle θ is 0 to θ1, the gear ratio Δθ / Δδ is set to be large so that the steered angle of the steered wheels 5 and 5 does not change so much even if the steering wheel 1 is greatly operated. . Since this area is sometimes used for fine adjustment of the course when passing on a narrow road, the gear ratio is increased, and the relationship between the steering angle θ and the turning angle δ is made linear. It becomes easier to perform corrective steering.
[0043]
In the section (ii) in which the steering angle is θ1 to θ2, the turning angle δ2 is set to a turning angle necessary when turning right and left at the intersection, and the steering angle θ2 at that time is set to about 90 deg. The steering angle δ2 is about 20 deg. The gear ratio of the steering angles θ1 to θ2 is given by a characteristic that smoothly connects the gear ratio of the steering angle θ1 and the gear ratio of the steering angle θ2 so that the gear ratio decreases as the steering angle θ increases.
[0044]
In the section (iii) where the steering angle is θ2 to θ3, the steering angle θ3 is a lock position. If the steering angle is set to about 140 deg, the steering wheel 1 can be operated without changing. The gear ratio at the steering angles θ2 to θ3 is further smaller than the section (ii) of the steering angles θ1 to θ2. In the region where the steering angle is θ2 to θ3, the steering angle is a region used when changing the direction or entering the garage. A large steering angle is required, but correction steering is also frequently performed. Since the change of the steering angle δ with respect to the steering angle θ is large, the correction steering becomes easier than the case of making the relationship non-linear by making the relationship between the steering angle θ and the steering angle δ linear.
[0045]
Next, the effect will be described.
In the vehicle steering control apparatus of the second embodiment, the following effects can be obtained in addition to the effects (1) and (2) of the first embodiment.
[0046]
(4) The gear ratio setting unit 10a is configured so that the steering angle θ of the steered wheels 5 and 5 with respect to the steering angle θ of the steering wheel 1 is (i) 0 to θ1, (ii) θ1 to In the three sections θ2, (iii) θ2 to θ3, the gear ratio Δθ / Δδ is constant in the sections (i) and (iii) , and in the section (ii) , the relationship between the steering angle θ and the turning angle δ. Since the gear ratio characteristic C is smoothly connected to the section (i) and the section (iii) , the first embodiment is achieved while achieving the ease of the correction steering in the course fine adjustment correction steering area and the full turning area. As described above, the steering discomfort due to the stepwise change of the gear ratio can be eliminated.
[0047]
(Third embodiment)
The third embodiment is an example in which steering reaction force torque control based on a steering reaction force torque ratio is added to the turning angle control of the first embodiment or the second embodiment.
[0048]
That is, a steering reaction force actuator 2 that generates a steering reaction force torque T on the steering wheel 1 and a target steering reaction force calculation unit 10b that calculates a target steering reaction force torque T ^* to the steering reaction force actuator 2 (target steering reaction force). Force calculating means).
[0049]
As shown in FIG. 7, the target steering reaction force calculation unit 10b responds as the gear ratio Δθ / Δδ decreases based on the gear ratio characteristic B or the gear ratio characteristic C set by the gear ratio setting unit 10a. Thus, the target steering reaction torque T ^* is calculated so that the steering reaction torque ratio ΔT / Δθ, which is the ratio of the steering reaction torque change to the steering angle change, increases. Since other configurations are the same as those of the first embodiment, illustration and description thereof are omitted.
[0050]
Next, the operation will be described.
[0051]
[Coordinated control of steering and steering reaction torque for steering]
In the case where the steering section and the steering section are mechanically separated and the steering section includes the steering reaction force actuator 2 that generates the steering reaction torque T, the steering reaction torque T can be arbitrarily generated. It becomes. When the gear ratio γ is made variable according to the steering angle θ, the steering angular velocity δ ′ changes even if the steering angular velocity θ ′ remains the same unless the steering reaction torque T changes, which causes confusion to the driver.
[0052]
Therefore, as shown in FIG. 7, as the gear ratio γ decreases, in other words, as the turning angle change Δδ increases with respect to the steering angle change Δθ, the steering reaction force torque ratio ΔT / Δθ is also increased. In this way, excessive turning of the steering wheel 1 is suppressed without the driver being aware of it, and sudden changes in vehicle behavior are reduced.
[0053]
Next, the effect will be described.
In the vehicle steering control device of the third embodiment, in addition to the effects (1) to (3) of the first embodiment or the effect (4) of the second embodiment, the following effects can be obtained. .
[0054]
(5) A steering reaction force actuator 2 that generates a steering reaction force torque T in the steering wheel 1 and a target steering reaction force calculation unit 10b that calculates a target steering reaction force torque T ^* to the steering reaction force actuator 2. The target steering reaction force calculation unit 10b is based on the gear ratio Δθ / Δδ set by the gear ratio setting unit 10a, and the steering reaction force against the steering angle change according to the decrease of the gear ratio Δθ / Δδ. In order to calculate the target steering reaction torque T ^* so that the steering reaction torque ratio ΔT / Δθ, which is the ratio of torque change, is increased, it is possible to suppress excessive turning of the steering wheel 1 without the driver being aware of it, and The effect that the behavior change can be reduced is obtained.
[0055]
(Fourth embodiment)
In the fourth embodiment, the steering reaction force torque control based on the steering reaction force torque ratio is added to the turning angle control of the first embodiment or the second embodiment, and the steering angular velocity is suppressed before the gear ratio changes. This is an example.
[0056]
That is, as shown in FIG. 8, the target steering reaction force calculation unit 10b changes the steering angle θ (change point) of the steering wheel 1 that changes the steering reaction force torque ratio ΔT / Δθ, and the gear ratio Δθ / Δδ changes. It is set closer to the neutral side than the steering angle θ (θ1, θ2). Since other configurations are the same as those of the first embodiment, illustration and description thereof are omitted.
[0057]
Next, the operation will be described.
[0058]
[Coordinated control of steering and steering reaction torque for steering]
In the third embodiment, as shown in FIG. 7, the change point of the gear ratio γ coincides with the change point of the steering reaction torque ratio, and when the gear ratio decreases, the steering reaction torque T increases to increase the steering wheel of the driver. The excessive cutting of 1 is suppressed.
[0059]
On the other hand, in the fourth embodiment, by increasing the steering reaction torque T before the gear ratio changes, it is possible to prevent the steering wheel 1 from being overcut prior to the change in the gear ratio. A sudden change in vehicle behavior due to excessive turning of the steering wheel 1 can be reliably reduced.
[0060]
Next, the effect will be described.
In the vehicle steering control device of the fourth embodiment, the following effects can be obtained in addition to the effects (1) to (3) of the first embodiment or (4) of the second embodiment. .
[0061]
(6) The target steering reaction force calculation unit 10b sets the steering angle θ of the steering wheel 1 that changes the steering reaction force torque ratio ΔT / Δθ closer to the neutral side than the steering angle θ that changes the gear ratio Δθ / Δδ. Since it is set, it is possible to effectively suppress the steering wheel 1 from being overcut prior to the change in the gear ratio.
[0062]
(5th Example)
The fifth embodiment is an example in which the steering reaction force torque control based on the steering angular velocity coefficient is added to the turning angle control of the first embodiment or the second embodiment.
[0063]
That is, as shown in FIG. 9, the target steering reaction force calculation unit 10b ′ sets the steering angular force θ ′ of the steering reaction force torque T in accordance with a decrease in the gear ratio Δθ / Δδ from the gear ratio setting unit 10a. The target steering reaction torque T ^* is increased by increasing the coefficient (dumping term) related to the component that depends, for example, the steering angular velocity θ ′ when calculating the steering reaction torque T. Since other configurations are the same as those of the first embodiment, illustration and description thereof are omitted.
[0064]
Next, the operation will be described.
[0065]
[Coordinated control of steering and steering reaction torque for steering]
In an apparatus having a steering reaction force actuator 2 that generates a steering reaction force torque T in the steering portion, the steering reaction force torque T generally has a steering angle θ. And steering angular velocity θ ′, turning angle δ, turning angular velocity δ ′, vehicle yaw rate ψ ′, lateral acceleration α, and the like.
[0066]
3 and 4, the steering reaction torque T is a function of the steering angle θ, and when the gear ratio Δθ / Δδ increases, the steering reaction torque ratio ΔT / Δθ is increased correspondingly. However, even if the coefficient (dumping term) related to θ ′ when calculating the torque T is increased, the steering angular velocity near the change point of the gear ratio is suppressed, so that the steering wheel 1 can be prevented from being overcut. .
[0067]
In this case, since the steering angular velocity at the return to the neutral side is also suppressed, by setting the value so that it does not return suddenly even if the driver reduces the steering force, the steering wheels 5 and 5 are rotated. A sudden change in vehicle behavior caused by a sudden change in the steering angle δ can also be suppressed.
[0068]
Next, the effect will be described.
In the vehicle steering control device of the fifth embodiment, (1) to (3) of the first embodiment, (4) of the second embodiment, or (5) of the third embodiment. Alternatively, in addition to the effect of (6) of the fourth embodiment, the following effect can be obtained.
[0069]
(7) The target steering reaction force calculation unit 10b ′ relates to the steering angular velocity θ ′ when calculating the steering reaction force torque T in accordance with the decrease in the gear ratio Δθ / Δδ from the gear ratio setting unit 10a. Since the target steering reaction torque T ^* is increased by increasing the coefficient, the driver can suppress the steering wheel 1 from being overcut and overturned without being conscious of it. A change in vehicle behavior can be reduced.
[0070]
As mentioned above, although the vehicle steering control apparatus of the present invention has been described based on the first to fifth embodiments, the specific configuration is not limited to these embodiments, and the scope of the claims is as follows. Design changes and additions are allowed without departing from the spirit of the invention according to each claim.
[0071]
For example, in the fifth embodiment, the steering reaction force torque control based on the steering angular velocity coefficient is added to the turning angle control of the first embodiment or the second embodiment, but the first embodiment or the second embodiment. The steering reaction force torque control based on (steering reaction force torque ratio + steering angular velocity coefficient) may be added to the turning angle control.
[Brief description of the drawings]
FIG. 1 is an overall system diagram showing a vehicle steering control apparatus according to a first embodiment;
FIG. 2 is a block diagram showing a steering angle control system of the first embodiment device.
FIG. 3 is a gear ratio characteristic diagram showing a relationship between a steering angle and a turning angle in a general vehicle.
FIG. 4 is a gear ratio characteristic diagram showing a relationship between a steering angle and a turning angle set in a gear ratio setting unit of the steering angle controller of the first embodiment device.
FIG. 5 is a gear ratio characteristic diagram showing a relationship between a steering angle and a turning angle set in a gear ratio setting unit of a steering angle controller of the second embodiment device.
FIG. 6 is a gear ratio characteristic diagram showing the relationship between the steering angle and the gear ratio set in the gear ratio setting unit of the steering angle controller of the first embodiment apparatus and the second embodiment apparatus.
FIG. 7 shows gear ratio characteristics indicating the relationship between the steering angle and the gear ratio set in the gear ratio setting unit of the steering angle controller of the third embodiment device, and the steering set in the target steering reaction force calculation unit. It is a contrast characteristic figure with the target steering reaction torque characteristic which shows the relationship between an angle and a target steering reaction torque.
FIG. 8 is a gear ratio characteristic indicating a relationship between a steering angle and a gear ratio set in a gear ratio setting unit of a steering angle controller of the fourth embodiment device, and a steering set in a target steering reaction force calculation unit. It is a contrast characteristic figure with the target steering reaction torque characteristic which shows the relationship between an angle and a target steering reaction torque.
FIG. 9 is a block diagram showing a steering angle control system of the fifth embodiment device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Steering wheel 2 Steering reaction force actuator 3 Torque sensor 4 Steering angle sensor 5 Steering wheel 6 Transmission part 7 Steering gear (steering device)
8 Steering actuator 9 Steering angle sensor 10 Steering angle controller (steering control means)
10a Gear ratio setting section (gear ratio setting means)
10b Target steering reaction force calculation unit (target steering reaction force calculation means)
10c Target turning angle calculation unit 11 Vehicle speed sensor 12 Yaw rate sensor

Claims (6)

A steering wheel that is not mechanically connected to the steering wheel steering device;
A steering actuator that applies its output to the steering device;
Gear ratio setting means for setting a gear ratio (Δθ / Δδ), which is a ratio between a change in the steering angle (θ) of the steering wheel and a change in the steering angle (δ) of the steered wheel;
Turning control means for driving the turning actuator so as to achieve a target turning angle (δ ^* ) calculated based on at least the set gear ratio (Δθ / Δδ) and the steering angle (θ);
In a vehicle steering control device comprising:
A steering reaction force actuator for generating a steering reaction force torque (T) on the steering wheel, and a target steering reaction force calculation means for calculating a target steering reaction force torque (T ^* ) to the steering reaction force actuator ,
The gear ratio setting means sets a gear ratio characteristic in which the gear ratio (Δθ / Δδ) decreases while the gear ratio (Δθ / Δδ) has a constant region as the steering angle absolute value | θ | increases. And
The target steering reaction force calculation means is based on the gear ratio (Δθ / Δδ) set by the gear ratio setting means, and the steering reaction force against the change in the steering angle as the gear ratio (Δθ / Δδ) decreases. A vehicle steering control device that calculates a target steering reaction torque (T ^* ) so that a steering reaction torque ratio (ΔT / Δθ) that is a ratio of torque change is increased . The vehicle steering control device according to claim 1,
The target steering reaction force calculating means is configured such that the steering angle (θ) of the steering wheel for changing the steering reaction force torque ratio (ΔT / Δθ) is closer to the neutral than the steering angle θ for changing the gear ratio (Δθ / Δδ). The vehicle steering control device is characterized in that it is set to the side. The vehicle steering control device according to claim 1 or 2,
The target steering reaction force calculation means calculates the steering angular velocity (θ) of the steering reaction force torque (T) as the gear ratio (Δθ / Δδ) decreases. ' ) To increase the component that depends on the target steering reaction torque (T ^* ) To increase the vehicle steering control device. The vehicle steering control device according to any one of claims 1 to 3 ,
The gear ratio setting means has a relationship of a steered wheel turning angle (δ) to a steering angle (θ) of a steering wheel.
(i) When the steering angle absolute value | θ | is approximately 40 ° (= θ1), the steering angle absolute value | δ | is approximately 5 °.
(ii) Steering angle absolute value | θ | is approximately 90 ° (= θ2) and turning angle absolute value | δ | is approximately 20 °.
(iii) Steering angle absolute value | θ | is approximately 140 ° (= θ3) and turning angle absolute value | δ |
A steering control device for a vehicle, wherein a gear ratio characteristic is set. The vehicle steering control device according to claim 4 ,
The gear ratio setting means has a relationship of a steered wheel turning angle (δ) to a steering angle (θ) of a steering wheel.
Steering angle θ is (i) 0 to θ1, (ii) θ1 to θ2, (iii) θ2 to θ3, and the gear ratio (Δθ / Δδ) is constant in each section.
A steering control device for a vehicle, wherein the gear ratio characteristic is set. The vehicle steering control device according to claim 4 ,
The gear ratio setting means has a relationship of a steered wheel turning angle (δ) to a steering angle (θ) of a steering wheel.
Steering angle θ is (i) 0 to θ1, (ii) θ1 to θ2, and (iii) θ2 to θ3, the gear ratio (Δθ / Δδ) is constant in section (i) and section (iii) In the section (ii) , the vehicle steering is characterized in that the relationship between the steering angle (θ) and the turning angle (δ) is set to a gear ratio characteristic that smoothly connects the section (i) and the section (iii). Control device.

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