JP3180505B2 - Steering reaction force control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering wheel and a steered wheel which are not linked, and drives a steering actuator based on a steering state of the steering wheel by a driver and a traveling state of the vehicle such as a vehicle speed. The present invention relates to a steering reaction force control device that is mounted on a vehicle configured to control and steer a steered wheel, and that applies a steering reaction force to a steering wheel.

[0002]

2. Description of the Related Art Conventionally, as such a steering reaction force control device, a device configured to control a steering reaction force in accordance with a steering angle (for example, Japanese Patent Application Laid-Open Nos. Hei 2-255597 and Hei 2-
2555568) has been proposed. The present applicant has also proposed an apparatus configured to determine a steering reaction force based on a motor drive current for steering wheel steering (Japanese Patent Laid-Open No. 4-365).
No. 673).

[0003]

However, in the configuration in which the steering reaction force is controlled in accordance with the steering angle, "the road surface reaction force cannot be transmitted to the steering wheel." However, there is a problem that a steering reaction force at an extremely low speed cannot be given accurately. ", And a steering reaction force control cannot be performed immediately after startup unless a steering angle sensor capable of detecting an absolute angle is provided. Was.

On the other hand, according to Japanese Patent Application Laid-Open No. 4-365673, it is possible to execute a control reflecting a road surface reaction force, and to control the vehicle immediately after the start-up. Vibration occurs. ","
An electric current for accelerating and decelerating the inertial load of the front wheel steering mechanism causes a collision at the beginning of turning and a dropout during reversal. There was a problem.

Therefore, the present invention can reflect the road surface reaction force in applying the steering reaction force, and can perform effective steering reaction force control immediately after starting, and furthermore, the vibration of the steering reaction force is generated. It is an object of the present invention to provide a steering reaction force control device that does not cause new problems such as the above.

[0006]

According to a first aspect of the present invention, there is provided a steering reaction force control device for linking a steering wheel and a steered wheel. A steering reaction force control device mounted on a vehicle configured to drive-control a steering actuator of a steered wheel based on a steering state of the vehicle and a traveling state of the vehicle, and applying a steering reaction force to a steering wheel; A reaction force actuator for applying a steering reaction force to the steering wheel, an actual relative angle detecting means for detecting an actual relative angle between the steering wheel and the steered wheels, and a target relative angle for calculating a target relative angle between the steering wheel and the steered wheels Angle calculation means, and reaction force control means for controlling the driving of the reaction force actuator in consideration of the deviation of the actual relative angle from the target relative angle when giving a steering reaction force to a steering wheel Characterized by comprising a.

According to a second aspect of the present invention, in the steering reaction force control device according to the first aspect, a steering angle detecting means for detecting a steering angle of the steering wheel, and a steering wheel for detecting a steering speed of the steering wheel. Speed detecting means, and vehicle speed detecting means for detecting a vehicle speed of the vehicle, wherein the reaction force control means determines a deviation of an actual relative angle with respect to the target relative angle in a predetermined low speed region when applying the steering reaction force. The driving control of the reaction force actuator is performed with emphasis on the steering angle and / or the steering speed in other regions.

[0008]

According to the steering reaction force control device of the present invention, the deviation of the actual relative angle between the steering wheel and the steered wheels with respect to the target relative angle is taken into account when applying the steering reaction force. Here, the deviation increases as the road surface reaction force increases. Further, the deviation between the actual relative angle and the target relative angle can be immediately and correctly detected immediately after the start. Further, such a deviation is
The larger the steering amount, the larger the value.

Therefore, according to the steering reaction force control device of the present invention, the road reaction force can be reflected and the steering reaction force can be accurately controlled even immediately after starting. Moreover, such a deviation directly represents the road surface reaction force, and is not affected by the inertial load of the steering actuator or the like.
There is no problem such as generation of vibration and generation of a feeling of penetration as described in US Pat.

[0010] According to the steering reaction force control device of the second aspect, in a predetermined low speed region, the steering reaction force is controlled with emphasis on the deviation of the actual relative angle from the target relative angle, and the steering reaction force is controlled in other regions. In, the steering reaction force is controlled with emphasis on the steering angle and / or the steering speed. That is, a steering reaction force reflecting the road surface reaction force is applied to steering during stationary or extremely low speed driving, and a steering reaction force reflecting the steering angle and / or the steering speed in a state such as normal driving. give.

As a result, the driver feels the steering reaction force mainly based on the road surface reaction force at the time of low speed including stationary, and at the time of normal driving or high speed driving, the steering reaction corresponding to the driver's own steering operation state. You can operate the steering wheel while feeling the power. Here, if the steering reaction force is given by strongly reflecting the steering angle and the steering speed even at a low speed, the steering wheel is returned even when the steering wheel should not be able to return completely due to the road surface reaction force. . On the other hand, in the configuration according to the second aspect of the present invention, such a disadvantage does not occur in the low-speed region because the deviation of the relative angle is more important.

On the other hand, since the road surface reaction force represented by the deviation of the relative angle is determined only when the steering is completed, from the viewpoint of the followability of the steering reaction force,
You will always be late. On the other hand, during high-speed running, the steering reaction force is determined with emphasis on the steering angle and / or the steering speed, so that the followability of the steering reaction force control during high-speed running is improved.

Therefore, when the configuration according to the second aspect is adopted, not only the road surface reaction force is reflected or control is enabled immediately after the start-up, but also over the entire range from the low speed range to the high speed range. It can give a comfortable steering feeling.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 is a schematic configuration diagram illustrating a configuration of an entire front wheel steering control device for a vehicle as an embodiment.

As shown in FIG. 1, a steering shaft 4 is connected to a steering wheel 2 steered by a vehicle driver.
A steering angle sensor 6 for detecting a steering angle of the steering wheel 2 by a vehicle driver is attached. The steering shaft 4 has a pulley 11 connected to an electric motor (hereinafter, referred to as a reaction motor) 8 for applying a steering reaction force to the steering wheel 2 via a well-known transmission mechanism, for example, a V-belt 10. Fixed.

On the other hand, a steering mechanism for steering the front wheels 12 of the vehicle is connected to a pinion shaft 14 having a pinion gear 14a fixed at one end, and left and right front wheels 12 (only one of which is shown in the figure). 14a and a rack 16 on which a rack tooth 16a to be engaged is formed. An electric motor for steering the front wheels (hereinafter, referred to as a motor) is connected to a pinion shaft 14 serving as an input shaft of the steering mechanism via a mechanical clutch 18 and a speed reducer 20 described later.
It is called a steering motor. ) 22 are connected. Therefore, if the steering motor 22 is energized and rotated, the reduction gear 2
0, the pinion shaft 1 via the mechanical clutch 18
4 rotates, and further, the rotation of the pinion shaft 14 causes the rack 16 to be displaced in the axial direction, so that the front wheels 12 are steered. Further, the pinion shaft 14 is provided with a relative angle sensor 24 for detecting a relative angle (relative angle) between the steering shaft 4 and the pinion shaft 14. The speed reducer 20 is a well-known speed reducer including a worm and a worm wheel.

Next, the reaction force motor 8 and the steering motor 22
Are driven by the control device 30. The control device 30
It is constituted by a well-known microcomputer including a CPU, a ROM, a RAM, and the like, and is based on detection signals from the steering angle sensor 6, the relative angle sensor 24, and a vehicle speed sensor 26 for detecting a running speed (vehicle speed) of the vehicle. By driving the reaction force motor 8 and the steering motor 22, respectively, the steering reaction force applied to the steering wheel 2 and the steering angle of the front wheels 12 are controlled.

The steering angle control and the reaction force control executed by the control device 30 will be described later in detail.
Next, as shown in FIGS. 1 and 2, the distal end of the steering shaft 4 has a shape with two flat surfaces, and is formed in a concave portion 14 b formed at an end of the pinion shaft 14 opposite to the pinion gear 14 a. Inserted without contact. A pair of protrusions 14c that function as a mechanical stopper for the steering shaft 4 are formed in the recess 14b of the pinion shaft 14. FIG. 2 shows the tip of the steering shaft 4 and the recess 14b of the pinion shaft 14 on the same plane.

Here, the joint between the steering shaft 4 and the pinion shaft 14 is formed as described above because the steering shaft 4 and the pinion shaft 14
This is for realizing the following three operation modes in accordance with the relative positional relationship with. That is, when the relative positional relationship between the two shafts is within the range of the angle θ1 shown in FIG. 2, the steering shaft 4 and the pinion shaft 14 are completely separated. Therefore, in this case, the operation mode is such that the steering angle of the front wheels 12 can be controlled only by the steering motor 22 without depending on the operation of the steering wheel 2.

When the relative positional relationship between the two shafts is within the range of the angle θ 2 shown in FIG. 2, the mechanical clutch 18 is disconnected from the pinion shaft 14 by the steering force applied to the steering wheel 2. Therefore, in this case, the operation mode is such that the steering angle control of the front wheels 12 by the steering motor 22 cannot be performed.

Next, when the relative positional relationship between the two shafts reaches the range of the angle θ3 shown in FIG. 2, the tip of the steering shaft 4 comes into contact with the projection 14c of the pinion shaft 14, so that the steering shaft 4 and the pinion The shaft 14 and the shaft 14 move together. Therefore, in this case, the operation mode is such that the front wheels 12 can be steered by the driver's steering force input via the steering wheel 2.

That is, in the front wheel steering apparatus of the present embodiment, as shown in FIG. 3, the steering angle of the front wheels 12 is changed by the rotation angle of the steering shaft 4 (ie, the steering angle) according to the relative positional relationship between the steering shaft 4 and the pinion shaft 14. The steering angle corresponding to the steering angle of the wheel 2).
It can be set arbitrarily within the range of 1.

Next, when the relative positional relationship between the steering shaft 4 and the pinion shaft 14 is within the range of the angle θ2 shown in FIG. 2, the steering shaft 4 is separated from the pinion shaft 14 by the steering force applied to the steering wheel 2. The mechanical clutch 18 will be described with reference to the sectional view shown in FIG.

As shown in FIG. 4, the mechanical clutch 18
A gear 44 is rotatably fixed to the pinion shaft 14 via a bearing 42. The gear 44 is connected to the steering motor 22 via the speed reducer 20, and is driven to rotate coaxially with the pinion shaft 14 by the rotation of the steering motor 22. Further, the gear 44 is connected to an armature 48 via a clutch portion 46, and by its rotation,
The armature 48 is driven to rotate. Still further, the armature 48 is connected to the pinion shaft 14 via a spline 50.
Is connected to a flange portion 14d formed around the concave portion 14b. Therefore, the armature 4
The driving force in the rotation direction is transmitted from the pinion shaft 8 to the pinion shaft 14, and the armature 48 can move in the axial direction.

On the other hand, the collar portion 14 of the pinion shaft 14
A bolt 52 is screwed to d, and the leaf spring 54 and its holding plate 56 are fixed by the bolt 52. For this reason, the armature 48 is urged toward the gear 44 by the leaf spring 54, and the rotation of the gear 44 via the clutch 46 is caused by the urging force.
8 will be transmitted. Although only one bolt 52 is shown in FIG.
Are actually screwed to three places where the collar 14d is divided into approximately three equal parts about the axis of the pinion shaft 14.

Next, the collar portion 14 of the pinion shaft 14
Between d and the armature 48, a rotor 58 formed in a substantially disk shape is disposed. This rotor 58 is shown in FIG.
As shown in the figure, the steering shaft 4
The shaft insertion hole 58a which can insert the tip of
There are three long holes 5 around which the bolts 52 can be inserted.
8b is drilled. And the shaft insertion hole 58a
Is formed so as to come into contact with the tip of the steering shaft 4 when the relative position between the steering shaft 4 and the pinion shaft 14 reaches the angle θ2 beyond the range of the angle θ1. Balls 60 are rotatably provided at three positions of the rotor 58 between the elongated holes 58b around the shaft insertion hole 58a.

On the other hand, on the surface of the armature 48 facing the rotor 58, a tapered recess 48a is formed corresponding to each of the balls 60. When the relative position between the steering shaft 4 and the pinion shaft 14 is at the center position of the aforementioned angle θ1, the armature 48 and the rotor 58, as shown in FIG.
8a.

The mechanical clutch 18 constructed as described above
In FIG. 6, when the relative position between the steering shaft 4 and the pinion shaft 14 is within the aforementioned angle θ1, the rotor 58 is not in contact with the steering shaft 4, and as shown in FIG. When the relative position between the steering shaft 4 and the pinion shaft 14 reaches the aforementioned angle θ2, the shaft insertion hole 58a of the rotor 58 comes into contact with the tip of the steering shaft 4 when the relative position between the steering shaft 4 and the pinion shaft 14 reaches the aforementioned angle θ2. Since the rotor 58 rotates together with the steering shaft 4, the ball 60 is moved into the concave portion 48a as shown in FIG.
Move along the tapered surface of
Push up in 8 directions.

As a result, when the relative position between the steering shaft 4 and the pinion shaft 14 reaches the above-mentioned angle θ2, a gap is formed in the clutch portion 46 connecting the armature 48 and the gear 44, and the steering motor 22 14 cannot be transmitted, and the above 3
Two operation modes are established.

Next, a description will be given of a steering motor driving process executed for the steering angle control and a reaction motor driving process executed for the reaction force control in the control device 30. First, FIG. 7 shows that the relative angle between the steering shaft 4 and the pinion shaft 14 is set within the range of the aforementioned angle θ1.
6 is a flowchart showing a steering motor driving process executed by the control device 30 every predetermined time (for example, 2 msec.) In order to control according to the steering angle of the steering wheel 2 and the running state (vehicle speed) of the vehicle.

As shown in FIG. 7, when this process is started, at step 110, the vehicle speed V detected by the vehicle speed sensor 26 as the running state detecting means is read, and at step 120, the steering angle detecting means is detected. The steering angle θH of the steering wheel 2 detected by the steering angle sensor 6 is read.

Next, in step 130, step 12
At 0, a change speed (steering angular speed) dθH of the steering angle θH is obtained from a deviation between the steering angle θH of the steering wheel 2 read this time and the steering angle θH (n-1) read last time. Then, in the following step 140, steps 110 and 1
Step V1 and the vehicle speed V and the steering angle θH read in Step 20
Based on the steering angular velocity dθH obtained in step 30,
Using (1), a process as a control target calculating means for calculating a target relative angle θr between the steering shaft 4 and the pinion shaft 14 is executed.

Θr = K1 (V) · θH + K2 (V) · dθH (1) In this equation (1), K1 (V), K2 (V)
Is a variable set according to the vehicle speed V. That is,
The variable K1 (V) is, as shown in FIG.
At low speeds, it becomes a positive value at low speeds to increase the gain, becomes negative as the vehicle speed V increases at medium speeds or higher, and becomes a constant negative value at high speeds, and is set to a total value by a variable K2 (V). The gain is prevented from increasing and the stability at the time of high-speed fine steering is improved. The variable K2 (V) is for compensating the steering delay at the time of middle and high speed and improving the maneuverability. As shown in FIG. 8B, the variable K2 (V) is synchronized with the variable K1 (V). It is set so as to increase as the vehicle speed V increases at a speed higher than the vehicle speed, and to become a substantially constant value at a high speed.

When the target relative angle θr is calculated in step 140 in this way, the process proceeds to step 150, in which the steering shaft 4 and the pinion shaft detected by the relative angle sensor 24 as the steering state detecting means. The relative angle (actual relative angle) θa with respect to 14 is read, and in the following step 160, the deviation Δθ between the target relative angle θr and the actual relative angle θa is calculated.

In the following step 170, a compensation operation (proportional + differential) for setting the deviation Δθ to zero is performed by using the following equation (2) using the calculated deviation Δθ as a parameter.
To calculate the driving torque (motor torque) Ta of the steering motor 22 and its driving direction.

Ta = Kp · △ θ + Kd · (d △ θ / dt) (2) where Kp is a proportional constant, Kd
Is a differential constant. Finally, in step 190, the torque command value Ta set as described above and the driving direction of the steering motor 22 are output to a steering motor drive circuit (not shown) built in the ECU 30. When the steering motor drive circuit receives the torque command value Ta, it drives the steering motor 22 with an energizing current according to the torque command value Ta.

On the other hand, the reaction motor driving process is executed according to the flowchart shown in FIG. This process is executed by the ECU 30 every predetermined time (for example, every 10 msec), similarly to the above-described steering motor driving process. When this process is started, first, in step 210, the steering angle θH of the steering wheel 2, the vehicle speed V, the actual relative angle θa from the relative angle sensor, and step 140 of the steering motor driving process.
The target relative angle θr calculated in step is read. Then, in step 220, a steering angle guard process is executed. This steering angle guard process is a process for limiting the steering angle θH to a range of ± θmax based on a map 225 as shown in FIG. θmax represents a range in which the steering wheel 2 is steered without being changed. The reason why such a guard is provided is that if the steering force is increased linearly beyond this, the weight of turning the steering will be felt non-linearly and the steering feeling will be reduced.

Following this guard processing, step 230
Is multiplied by a steering angle gain Kp, which is a function of the vehicle speed V, to obtain a first steering reaction force component T corresponding to the steering angle θH.
Calculate s1. The first steering reaction force component Ts1 is for giving the driver a steering response. The steering angle gain Kp is determined based on a map 235 as shown in FIG. This steering angle gain Kp
Is "0" when the vehicle is stopped, and increases as the vehicle speed V increases so that the steering becomes heavier, as in a normal vehicle speed-sensitive power steering. Is set to

In step 240, the steering angle θH is differentiated to calculate a steering angular velocity dθH. Then, in step 250, a steering angular velocity guard process is executed. This steering angular velocity guard processing is performed in a map 25 as shown in FIG.
5, the steering angular velocity dθH is limited to a range of ± dθmax. dθmax is a value for preventing the overflow of the calculation and preventing the steering from becoming too heavy during high-speed steering.

Following this guard processing, step 260
Then, a second steering reaction force component Ts2 corresponding to the steering angular speed dθH is calculated by multiplying the steering angular speed gain Dp which is a function of the vehicle speed V. This second steering reaction force component T
s2 is for compensating steering damping. The steering angular velocity gain Dp is determined based on a map 265 as shown in FIG. The steering angular speed gain Dp is “0” when the vehicle is stopped, and is set to rise with the vehicle speed more than the steering angle gain Kp, and to be substantially constant in a high speed range.

The steering angle gain Kp and the steering angular velocity gain D
By calculating the steering reaction force components Ts1 and Ts2 so as to increase as the vehicle speed V increases, p serves to improve the steering stability during high-speed running of the vehicle. In the following step 270, the relative angle deviation △ θ is calculated by subtracting the actual relative angle θa from the target relative angle θr. Then, at step 280, the relative angle deviation △ θ is multiplied by the relative angle deviation gain Ke, which is a function of the vehicle speed V, to obtain the relative angle deviation △ θ.
The third steering reaction force component Ts3 corresponding to θ is calculated. The third steering reaction force component Ts3 is for feeding back the road surface reaction force to the steering. The relative angle deviation gain Ke is determined based on a map 285 as shown in FIG. The relative angle deviation gain Ke takes a predetermined value of 0 or more even when the vehicle is stopped, rises greatly as the vehicle speed increases, takes the maximum value in an extremely low speed region, and increases as the vehicle speed changes from low to medium speed. Contrary to the steering angle gain Kp, etc.,
It is set to decrease.

When the third steering reaction force Ts3 has been calculated in this way, a first-order lag filter process is performed at step 290. This processing is executed by using the following well-known discretization formula (3). y (n) = C0.x (n) + C1.y (n-1) (3) where C0 and C1 are coefficients, y (n-1) is an output one sampling period before, and x ( n) is the current input, y
(N) is an output.

As described above, the steering angle θH and the steering angular velocity dθ
H, the steering reaction force component T corresponding to the relative angular deviation △ θ, respectively.
When s1, Ts2, and Ts3 are calculated, the process proceeds to step 300, where the respective steering reaction force components Ts1 and Ts3 are calculated.
The total steering reaction force Ts applied to the steering wheel 2 is calculated by adding 2, Ts3. Then, the process proceeds to a step 310, wherein a process of guarding the total steering reaction force Ts within a range of ± Tsmax using a map 315 shown in FIG. 15 is executed. Then, in the following step 320, the integrated steering reaction force Ts after the guard processing is output to a current control circuit built in the ECU 30 as a torque command value representing the current supplied to the reaction force motor 8. When the current control circuit receives the torque command value Ts, the current control circuit drives the reaction motor 8 at a constant current with a current flowing according to the value. Since the reaction motor 8 is a DC motor having a magnet as a field, the motor current is proportional to the motor torque, and the torque can be controlled by the current.

FIG. 16 schematically shows the flow of data in the above-described reaction motor driving process. By adopting such a configuration, the present embodiment has the following operations and effects. When the vehicle stops, the steering angle gain Kp and the steering angular velocity gain Dp are “0”, and only the relative angle deviation gain Ke has a predetermined value. Therefore,
The steering reaction force while the vehicle is stopped is controlled only by the third steering reaction force component Ts3 corresponding to the relative angular deviation Δθ. Here, the third steering reaction force component Ts3 mainly corresponds to the road surface reaction force. As a result, when the vehicle is stationary when the vehicle is stopped, a steering feeling that accurately reflects the road surface reaction force can be provided, and the steering wheel 2 does not return too much after the steering is completed. Further, when the vehicle is stopped, the reaction force control corresponding to the relative angle deviation △ θ is performed, so that the reaction force control can be immediately executed even in a state where the absolute steering angle is not known, such as immediately after starting.

In an extremely low speed range from the stop, the steering angle gain Kp is "0" or a small value, and the steering angle speed gain Dp is slightly large, and the relative angle deviation gain Kp is small.
e increases to its maximum value. Therefore,
The total steering reaction force Ts is based on the relative angular deviation Δθ, and the steering angular velocity dθH is sufficiently considered. As a result, the road surface reaction force can be sufficiently reflected in response to the phenomenon at extremely low speeds, and appropriate damping compensation can be made in accordance with the steering operation conditions. It is possible to perform control that properly reflects the force. Further, since the relative angular deviation △ θ and the steering angular velocity dθH can be accurately obtained even in a situation where the vehicle has just started and an absolute steering angle cannot be obtained, it is always possible to accurately execute the steering reaction force control. it can.

On the other hand, in the middle to high speed range, the relative angle deviation gain K
e is smaller than the other gains Kp, Dp, and conversely, these other gains Kp, Dp are configured to approach the maximum value. Therefore, in the middle to high speed range, the steering reaction force control is executed with emphasis on the steering angle θH and the steering angular velocity dθH. As a result, it is possible to provide a crisp and comfortable steering feeling by appropriately responding to the driver's steering and neglecting factors that always involve a time delay such as road surface reaction force. It should be noted that the steering neutral position can be sufficiently confirmed when the vehicle reaches the middle to high speed range, and the steering angle θH can be accurately detected without providing an absolute steering angle sensor.

As described above, in the present embodiment, by using the relative angular deviation Δθ in the steering reaction force control, the road surface reaction force can be accurately reflected, and the control can be performed even immediately after starting. Moreover, the relative angle deviation △ θ is not affected by the occurrence of high-frequency vibration such as the steering motor drive current or the inertial load of the motor, so that the driver does not feel uncomfortable.

In addition, since the relative angle deviation △ θ is emphasized in the stationary and extremely low speed regions, and the steering angle θH is emphasized in the middle and high speed regions, a natural steering reaction force can be obtained from the stop to the high speed region. And a comfortable steering feeling is provided to the driver. As mentioned above, although one Example of this invention was described, this invention is not limited to the said Example, It can apply to various front-wheel steering control apparatuses in the range which does not deviate from the summary of this invention.

For example, in the above embodiment, the relative angle deviation .DELTA..theta. Is reflected to some extent even in a high speed range, but it may not be reflected at all. Conversely, when the vehicle is stopped, the steering angular velocity d
Although the configuration is such that θH and the like are not reflected, the configuration may be such that some of these are reflected.

[0050]

As described in detail above, according to the steering reaction force control device of the first aspect, the road surface reaction force can be reflected, and effective steering reaction force control is performed immediately after starting. In addition, it does not give a sense of incongruity such as a feeling of vibration and a feeling of bumping.

According to the steering reaction force control device of the second aspect, in addition to the above-described effects, a comfortable steering feeling can be provided over the entire range from the low speed range to the high speed range.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a configuration of an entire front wheel steering control device according to an embodiment.

FIG. 2 is an explanatory diagram illustrating a configuration of a connection portion between a steering shaft and a pinion shaft.

FIG. 3 is a diagram illustrating a relationship between a rotation angle of a steering shaft and a front wheel steering angle.

FIG. 4 is a cross-sectional view illustrating a configuration of a mechanical clutch.

FIG. 5 is an explanatory diagram illustrating a configuration of a rotor provided in a mechanical clutch and a relationship between the rotor and a steering shaft.

FIG. 6 is an operation explanatory diagram illustrating an operation of the mechanical clutch.

FIG. 7 is a flowchart illustrating a steering motor driving process executed by the ECU.

FIG. 8 is a diagram illustrating characteristics of variables of an arithmetic expression used when calculating a target relative angle.

FIG. 9 is a flowchart illustrating a reaction motor driving process executed by the ECU.

FIG. 10 is a diagram for steering angle guard processing.

FIG. 11 is a diagram illustrating characteristics of a steering angle gain Kp.

FIG. 12 is a diagram for a steering angular velocity guard process.

FIG. 13 is a diagram illustrating characteristics of a steering angular velocity gain dp.

FIG. 14 is a diagram illustrating characteristics of a relative angle deviation gain Ke.

FIG. 15 is a diagram for guard processing of a total steering reaction force.

FIG. 16 is a schematic diagram illustrating a flow of data in a reaction motor driving process.

[Explanation of symbols]

2 ... steering wheel, 4 ... steering shaft, 6 ... steering angle sensor, 8 ... reaction motor, 10 ... V belt, 11 ... pulley, 12 ... front wheel, 14 ... pinion shaft, 16 ... rack, 18 ... mechanical clutch, 20: reduction gear, 22: steering motor, 24: relative angle sensor, 26: vehicle speed sensor, 30: control device.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-133862 (JP, A) JP-A-4-133386 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B62D 6/00

Claims (2)

(57) [Claims] A steering wheel and a steered wheel are linkless, and mounted on a vehicle configured to drive and control a steering actuator of a steered wheel based on a steering state of the steering wheel and a running state of the vehicle. A steering reaction force control device that applies a steering reaction force to a steering wheel, a reaction force actuator that applies a steering reaction force to the steering wheel, and an actual relative angle detection that detects an actual relative angle between the steering wheel and the steered wheels. Means, a target relative angle calculating means for calculating a target relative angle between the steering wheel and the steered wheels, and a deviation of the actual relative angle from the target relative angle in applying a steering reaction force to the steering wheel. And a reaction force control means for controlling the driving of the reaction force actuator. 2. The steering reaction force control device according to claim 1, wherein: a steering angle detecting means for detecting a steering angle of the steering wheel; a steering speed detecting means for detecting a steering speed of the steering wheel;
Vehicle speed detecting means for detecting the vehicle speed of the vehicle, wherein the reaction force control means gives importance to the deviation of the actual relative angle with respect to the target relative angle in a predetermined low speed region when giving the steering reaction force, In the region, a steering reaction force control device is configured to perform drive control of the reaction force actuator with emphasis on the steering angle and / or steering speed.