JP2003118621A - Steering control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform an appropriate corrective steering and enable extracting a steering operation based on apparatus steering intention of a driver. SOLUTION: The steering control device is equipped with a controller 30 having a correction function of target steering reaction to correct a reaction of target steering operation based on a corrected steering angle and a calculation contents correction function of target steering turn angle to correct a steering gain based on a corrected steering angle. When the controller 30 detects that the change direction of the target steering turn angle before correction is the same as the change direction of corrected steering angle, it corrects the target steering reaction to the direction of increasing the target steering reaction and sets the steering gain smaller than usual.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering control device for steering a wheel, and more particularly to a steering control device capable of changing a steering angle without mechanically connecting the steering wheel to the wheel.

[0002]

2. Description of the Related Art For example, when braking is performed on a road surface having different road surface friction coefficients on the right side and the left side, a difference occurs between the braking force generated on the right side wheel and the braking force generated on the left side wheel, resulting in a yaw moment. Occurs. In such a situation, there is a technique that controls the brakes of the wheels to suppress changes in vehicle behavior. For example, in this technology, in order to suppress changes in vehicle behavior, all wheels are braked by the braking force at the wheel with the lowest friction coefficient, but this does not provide sufficient braking force, and the braking distance There was a problem that was extended.

On the other hand, as a conventional technique, Japanese Patent Laid-Open No. 2000-
There are vehicle steering devices disclosed in Japanese Patent No. 43747 and Japanese Patent Laid-Open No. 2001-30931. JP 2000-
The steering apparatus disclosed in Japanese Patent No. 43737 controls the steering actuator so that the target lateral acceleration and the target yaw rate match the actual lateral acceleration and yaw rate, thereby performing the correction steering so as to cancel the yaw moment due to the difference between the left and right braking forces. is doing. As a result, the maximum braking force can be generated on each wheel, and the braking distance is prevented from being extended.

Further, the steering device of Japanese Unexamined Patent Publication No. 2001-30931 prevents the steering reaction force from including the corrected steering amount when the corrected steering is performed, thereby preventing the steering feeling from deteriorating. Even with such a steering device, the maximum braking force can be generated at each wheel, so that it is possible to prevent the braking distance from being extended.

[0005]

By the way, in the case of braking on a road surface where the road surface friction coefficient is different between the left and right wheels, the vehicle goes straight with a vehicle body slip angle with respect to the traveling direction, that is, You will be skewed. In such a state, the slip angle of the vehicle body is small, but
Since the traveling direction of the vehicle does not change, the driver can drive with peace of mind, but a skilled driver may perform a correction steering for correcting the vehicle attitude when the vehicle body slip angle is reached.

However, the above-mentioned Japanese Patent Laid-Open No. 2000-4374.
In the steering devices disclosed in Japanese Patent Laid-Open Publication No. 7-70, and Japanese Patent Laid-Open No. 2001-30931, since the direction of the corrected steering matches the direction of the corrected steering, the steering operation is based on the driver's intention to turn when the steering operation is performed. The steering actuator is controlled so that the driver makes a turning motion despite the driver's intention to perform the corrective steering because it cannot determine whether it is due to the corrective steering for correcting the vehicle attitude. However, there is a problem that the steering is judged to be a correction steering even if the driver intends to make a turn, and as a result, the start of turning is delayed. In this case, it cannot be said that the appropriate correction steering is performed, and further, the steering intention of the driver is not reflected in the vehicle behavior.

Therefore, the present invention has been made by paying attention to such a conventional problem, and makes it possible to perform an appropriate correction steering and to extract a steering operation based on the driver's clear steering intention. It is an object of the present invention to provide a steering control method and a steering device.

[0008]

In order to solve the above problems, a steering control device according to a first aspect of the present invention is a steering input device including a steering wheel, and the steering input device is mechanically uncoupled. And a steering device that steers the steered wheels, a steering actuator that applies a driving force to the steering device, a steering angle detection unit that detects a steering angle of the steering wheel, and a steering wheel that steers the steered wheels. Angle detecting means for detecting an angle, target turning angle calculating means for calculating a target turning angle based on the steering angle, and the turning actuator so that the turning angle approaches the target turning angle. A steering control means for driving the steering input device, a steering reaction force actuator for applying a steering reaction force to the steering input device, a vehicle state detection means for detecting an actual vehicle state, the steering angle and the actual vehicle state. Goals based Target steering reaction force calculation means for calculating the steering reaction force, steering reaction force control means for driving the steering reaction force actuator based on the target steering reaction force, and vehicle state expected by the driver based on the steering angle Vehicle state expectation value detection means for detecting, a corrected steering angle calculation means for obtaining a corrected steering angle such that the actual vehicle state approaches the vehicle state expected by the driver, and based on the corrected steering angle And a target steering angle correction means for correcting the target steering angle, a target steering reaction force correction means for correcting the target steering reaction force based on the corrected steering angle is provided. It is characterized by that.

A steering control device according to a second aspect of the present invention includes a steering input device including a steering wheel, and a steering device that is mechanically uncoupled from the steering input device and steers the steered wheels. A steering actuator that applies a driving force to the steering apparatus, a steering angle detection unit that detects a steering angle of the steering wheel, a steering angle detection unit that detects a steering angle of the steered wheels, and the steering angle. Target steering angle calculation means for calculating a target steering angle based on the above, steering control means for driving the steering actuator so that the steering angle approaches the target steering angle, and the steering input device. A steering reaction force actuator that applies a steering reaction force, a vehicle state detection unit that detects an actual vehicle state, and a target steering reaction force calculation that calculates a target steering reaction force based on the steering angle and the actual vehicle state. Means and Steering reaction force control means for driving the steering reaction force actuator based on the target steering reaction force, vehicle state expected value detection means for detecting a vehicle state expected by the driver based on the steering angle, and the actual Corrected turning angle calculation means for obtaining a corrected turning angle such that the vehicle state approaches the vehicle state expected by the driver, and target turning angle correction for correcting the target turning angle based on the corrected turning angle. The target steering angle calculation content correction means for correcting the calculation content of the target steering angle calculation means on the basis of the corrected steering angle.

A steering control device according to a third aspect of the present invention includes a steering input device including a steering wheel, and a steering device that is mechanically uncoupled from the steering input device and steers the steered wheels. A steering actuator that applies a driving force to the steering apparatus, a steering angle detection unit that detects a steering angle of the steering wheel, a steering angle detection unit that detects a steering angle of the steered wheels, and the steering angle. Target steering angle calculation means for calculating a target steering angle based on the above, steering control means for driving the steering actuator so that the steering angle approaches the target steering angle, and the steering input device. A steering reaction force actuator that applies a steering reaction force, a vehicle state detection unit that detects an actual vehicle state, and a target steering reaction force calculation that calculates a target steering reaction force based on the steering angle and the actual vehicle state. Means and Steering reaction force control means for driving the steering reaction force actuator based on the target steering reaction force, vehicle state expected value detection means for detecting a vehicle state expected by the driver based on the steering angle, and the actual Corrected turning angle calculation means for obtaining a corrected turning angle such that the vehicle state approaches the vehicle state expected by the driver, and target turning angle correction for correcting the target turning angle based on the corrected turning angle. And a target steering reaction force correction means for correcting the target steering reaction force based on the corrected steering angle, and a target steering angle calculation means based on the corrected steering angle. Target steered angle calculation content correction means for correcting the calculation content of.

According to a fourth aspect of the present invention, there is provided the steering control device according to the first or third aspect, in which the change direction of the target turning angle before correction and the change direction of the correction turning angle are the same. In addition to the change direction coincidence detecting means for detecting that the target steering reaction force correction means, when the change direction coincidence detecting means detects that the change directions coincide with each other, It is characterized in that the target steering reaction force is corrected in an increasing direction.

According to a fifth aspect of the present invention, there is provided the steering control device according to the second or third aspect, in which the direction of change of the target turning angle before correction and the direction of change of the corrected turning angle are the same. With the change direction coincidence detection means for detecting that the target turning angle calculation content correction means,
When it is detected by the change direction coincidence detection means that the change directions are coincident with each other, the change in the target turning angle with respect to the change in the steering angle is smaller than in other cases. It is characterized in that the contents of the calculation are corrected.

According to a sixth aspect of the present invention, there is provided the steering control device according to the first, third or fourth aspect, in which the target steering reaction force correction means corrects the correction amount of the target steering reaction force.
The feature is that the determination is made based on the steering angular velocity. According to a seventh aspect of the present invention, there is provided the steering control device according to the first, third, fourth, or sixth aspect, wherein the target steering reaction force correction means changes the degree of correction according to the vehicle speed. It is characterized by

According to an eighth aspect of the present invention, in the steering control apparatus according to the second, third or fifth aspect, the target steering angle calculation content correction means changes the degree of correction according to the vehicle speed. It is characterized by that. The steering control device according to claim 9 is the steering control device according to any one of claims 1 to 8,
It is characterized in that the vehicle state is a yaw rate.

A steering control device according to a tenth aspect of the present invention is
The steering control device according to any one of claims 1 to 8, wherein the vehicle state is a lateral acceleration of the vehicle. The steering control device according to claim 11 is the steering control device according to any one of claims 1 to 8, wherein the vehicle state is both a yaw rate and a lateral acceleration of the vehicle. .

[0016]

In the steering control device according to the present invention, the target steering reaction force correction means corrects the target steering reaction force based on the corrected turning angle, so that the vehicle state is corrected by the corrected turning angle. The steering reaction force applied to the steering wheel changes when the vehicle is on, and this allows the driver to be informed via the steering operation that the vehicle condition has been corrected to meet the intention. become.
Therefore, it is possible to perform the appropriate correction steering and extract the steering operation based on the driver's clear steering intention.

In the steering control device according to the second aspect of the present invention, the target steering angle calculation content correction means corrects the calculation content of the target steering angle calculation means based on the corrected steering angle. If the vehicle condition has been corrected by
It is possible to change the reaction of the steered wheels with respect to the steered angle. Accordingly, the steering control device can notify the driver that the vehicle state has been corrected so as to meet the intention through the reaction of the steered wheels to the steering operation. Therefore, it is possible to perform the appropriate correction steering and extract the steering operation based on the driver's clear steering intention.

In the steering control device according to the third aspect, the target steering reaction force correction means corrects the target steering reaction force based on the corrected turning angle, and the target steering angle calculation content correction means corrects it. By correcting the calculation contents of the target turning angle calculation means based on the turning angle, the steering reaction force applied to the steering wheel changes when the vehicle state is corrected by the corrected turning angle. Furthermore, since the reaction of the steered wheels with respect to the steered angle changes, the driver can confirm that the vehicle condition is corrected so as to meet the intention through the steering operation and the reaction of the steered wheels to the operation. It becomes possible to inform. Therefore, it is possible to perform the appropriate correction steering and extract the steering operation based on the driver's clear steering intention.

Further, the steering control device according to a fourth aspect of the present invention, when it is detected that the changing directions of the target turning angle before correction and the changing direction of the corrected turning angle are the same. Means that the driver performs the corrective steering, and the target steering reaction force is corrected in the increasing direction to make the steering operation heavy, and the vehicle state is corrected so that the driver follows the intention. It becomes possible to inform.

Further, in the steering control device according to the present invention, when it is detected that the direction of change of the target turning angle before correction and the direction of change of the corrected turning angle are detected, Assuming that the driver is performing corrective steering, the reaction of the steered wheels to the steering operation is delayed by making the change in the target steered angle with respect to the change in the steering angle smaller than in other cases. , It becomes possible to inform the driver that the vehicle condition has been modified to meet the intention.

Further, the steering control device according to the present invention corrects the target steering reaction force based on the steering angular velocity and corrects the steering reaction force according to the steering angular velocity, so that the driver feels uncomfortable. It is possible to correct the steering reaction force that does not exist. For example, the steering reaction force for the correction does not occur during steering, so that the driver does not feel uncomfortable. Further, the steering control device according to claim 7 changes the degree of correction of the target steering reaction force in accordance with the vehicle speed, so that the correction of the target steering reaction force reflects the vehicle speed and becomes more natural. There is.

Further, in the steering control device according to the present invention, the degree of correction of the target turning angle is changed according to the vehicle speed, so that the correction of the target turning angle reflects the vehicle speed, which is more natural. It has become. Further, in the steering control device according to the ninth aspect, since the vehicle state is the yaw rate, it is possible to easily detect the vehicle state. Further, in the steering control device according to the tenth aspect, the vehicle state is the lateral acceleration of the vehicle, so that the vehicle state can be easily detected. Further, in the steering control device according to the eleventh aspect, since the vehicle state is both the yaw rate and the lateral acceleration of the vehicle, it is possible to easily detect the vehicle state.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A plurality of embodiments of the present invention will be described in detail below with reference to the drawings. (1) First Embodiment FIG. 1 shows the configuration of a steering control device to which the first embodiment is applied. In the steering control device, left and right front wheels 1a and 1b, which are steered wheels, are supported by axles 2a and 2b so as to be rotatable about a steering axis with respect to a vehicle body.

Axles 2a, 2 of left and right wheels 1a, 1b
One ends of the tie rods 3a and 3b are swingably connected to b. And each tie rod 3a, 3
The other end of b is the rack shaft 5 of the steering rack 4.
Is swingably connected to each end of the. A pinion gear 6 meshes with the rack shaft 5, and the pinion gear 6
Is attached to one end of a pinion shaft 8 attached to the steered motor 7 via a reduction gear.

A steering angle sensor 21 for detecting the actual steering angle as the rotation of the pinion shaft 8 is attached to the tip of the pinion shaft 8. Further, a rack stroke sensor 22 is attached to the rack shaft 5 to detect a rack stroke of the rack shaft 5 which is moved by converting the rotation of the pinion shaft 8. Here, the axles 2a and 2b and the tie rod 3
The a, 3b, the steering rack 4, and the pinion shaft 8 constitute a steering device that steers the left and right wheels 1a, 1b, and are mechanically connected to a steering wheel 13 described later, like a general vehicle. However, the steering input device including the steering wheel 13 is mechanically uncoupled. Further, the turning motor 7 constitutes a turning actuator that applies a driving force to the turning device.

The column shaft 11 is, as described above,
The steering device and the steering input device are mechanically uncoupled from each other, but are not connected to the pinion shaft 8. The steering angle of the steering wheel 13 is applied to the column shaft 1 as the column shaft 1.
A first steering angle sensor 23 that detects the rotation angle of 1 is attached. A reaction force motor 12 is attached to the column shaft 11 via a reduction gear.
Since the column shaft 11 is not connected to the pinion shaft 8, the reaction force from the road surface generated by a normal steering wheel is not generated in the steering wheel 13, and the reaction force motor 12 generates a steering reaction force. Is equipped with. In addition, the reaction force motor 12 includes the column shaft 1
A second steering angle sensor 24 that detects the rotation angle of 1 as the rotation angle of the reaction force motor 12 is attached. Here, the reaction force motor 12 constitutes a steering reaction force actuator that applies a steering reaction force to the steering input device.

Further, the steering control device comprises a lateral acceleration sensor 26 for detecting a lateral acceleration applied to the vehicle, a yaw rate sensor 27 for detecting a yaw rate of the vehicle, and a wheel speed sensor 28 for detecting a vehicle speed. The steering control device controls each unit by the controller 30. FIG. 2 shows a specific configuration of the controller 30.
The controller 30 includes a processing unit 31 and drivers 34, 3
It is equipped with 5.

The processing unit 31 is configured to perform various kinds of signal processing, and specifically, UPP (Universal Puls).
e Processor) 32, A / D conversion circuit 33, and CPU 3
It is equipped with 4. The CPU 34 includes a turning angle sensor 21, a first steering angle sensor 23, and a second steering angle sensor 23 via the UPP 32.
Sensor inputs are made from the steering angle sensor 24 and the vehicle speed sensor 28. In addition, the CPU 34 has an A / D
Sensor inputs from the rack stroke sensor 2, the steering torque sensor 25, the lateral acceleration sensor 26, and the yaw rate sensor 27 are made via the conversion circuit 33.

The first driver 35 drives the reaction force motor 12, and the second driver 36 is also provided.
Is for driving the second steering motor 7. The first and second drivers 35 and 36 are the CPU
It is controlled by a PWM (Plus Width Modulation) signal from 34. Here, the current value (or voltage value) output from the second driver 34 to the steering motor 7 and the current value (or voltage value) output from the first driver 35 to the reaction force motor 12 are detected by the CPU 34. In other words, the CPU 34 can be detected by the current sensor.

In the structure of such a steering control device, the first and second steering angle sensors 23, 24 constitute steering angle detecting means for detecting the steering angle of the steering wheel 13, and the rack stroke sensor 2 Left and right wheel 1
a steering angle detecting means for detecting the steering angles of a and 1b,
At least one of the lateral acceleration sensor 26 and the yaw rate sensor 17 constitutes vehicle state detection means for detecting an actual vehicle state. Further, the first driver 35 constitutes a steering reaction force control means for driving the reaction force motor 12 based on the target steering reaction force, and the second driver 34 rotates so that the steering angle approaches the target steering angle. A steering control means for driving the steering motor 7 is configured.

Next, the processing contents of the controller 30 will be specifically described. First, the processing procedure for driving the steering motor 7 will be described with reference to the flowchart shown in FIG. First, in step S1, when the steering wheel 13 is operated during traveling, the first steering angle sensor 2
The detection value corresponding to the rotation angle of the steering wheel 13 is read into the CPU 34 via the UPP 32 by the method of 3.

Next, in step S2, the CPU 34
Calculates a target steering angle (1) which is a target steering angle corresponding to the rotation angle of the steering wheel 13. That is, the target steering angle calculation function in the controller 30 calculates the target steering angle based on the steering angle. Here, the target rudder angle (1)
Corresponds to the pinion rotation angle for turning the wheels 1a and 1b to the target steering angle. The calculation of the target rudder angle (1) is
Specifically, the steering angle of the steering wheel 13 is multiplied by the steering gain to obtain the target steering angle (1).

As the steering gain, for example, a yaw rate correction coefficient is used. As shown in FIG. 4, the yaw rate correction coefficient is obtained by expressing the yaw rate response gain with respect to the steering angle as a parameter of the vehicle speed, and is obtained as a function of the steering angle and the vehicle speed. The yaw rate response for the same steering angle depends on the vehicle speed. It is what I asked for. By using the yaw rate correction coefficient as the steering gain, the same yaw rate response can be obtained for the same steering angle even at different vehicle speeds.

Next, in step S3, the CPU 34
Thus, the target value of the yaw rate intended by the driver is calculated from the steering angle. That is, the vehicle state expected value detecting means in the controller 30 detects the vehicle state expected by the driver based on the steering angle. As the target value of the yaw rate, for example, a mathematical model of the vehicle is described inside the controller 30 (using a predetermined program), and the yaw rate obtained by calculation by inputting the steering angle and the vehicle speed into the vehicle model is the target yaw rate. Get as. The yaw rate indicates the vehicle state, and the target yaw rate indicates the vehicle state expected by the driver based on the steering angle.

Next, in step S4, the actual yaw rate of the vehicle is read from the yaw rate sensor 27 into the CPU 34 through the A / D conversion circuit 33, and then in step S5.
In step 3, the CPU 34 compares the actual yaw rate with the target yaw rate, and calculates the corrected steering angle according to the deviation from the target yaw rate. That is, the corrected steering angle calculation means in the controller 30 obtains a corrected steering angle (corrected steering angle) such that the actual vehicle state approaches the vehicle state expected by the driver.

Next, in step S6, the CPU 34 obtains the target steering angle as the sum of the target steering angle (1) and the corrected steering angle. That is, the target turning angle correction function of the controller 30 corrects the target turning angle based on the corrected turning angle. Next, in step S7, the pinion rotation angle detected by the turning angle sensor 21 is set to the CPU 3
Read in 4. Then, in step S8, the CPU
By 34, the command current value to the steering motor 7 is determined according to the deviation between the target steering angle obtained in step S6 and the actual steering angle from the steering angle sensor 21.

Next, in step S9, the CPU 34
Thus, the PWM according to the deviation between the command current value and the detected current value is adjusted so that the current value (detected current value) output to the steering motor 7 detected by the current sensor and the determined command current value match. Determine the duty. Next, in step S10, the second driver 36 causes the PW
The turning motor 7 is turned on / off by the M duty.
To drive. That is, the steering motor 7 is driven so as to obtain the deviation between the target steering angle and the actual steering angle and reduce the deviation.

Then, these steps S1 to S
The process of 10 is repeatedly executed at predetermined time steps. According to the above processing procedure, the controller 3
0 drives the steering motor 7. Next, a processing procedure for driving the reaction force motor 12 will be described with reference to the flowchart shown in FIG.

First, in steps S11 to S16, the detected values of the vehicle speed sensor 28, the first steering angle sensor 23, the lateral acceleration sensor 26, and the yaw rate sensor 27 are
CPU 3 via UPP 32 or A / D conversion circuit 33
4, the CPU 34 calculates the steering reaction force corresponding to each value, and in the subsequent step S17, the steering reaction force is calculated as the sum of the steering reaction forces. That is, the target steering reaction force calculation function of the controller 30 calculates the target steering reaction force based on the steering angle and the actual vehicle state.

Next, in step S18, the CPU 3
4, the direction of change of the target steering angle (1) and the direction of the corrected steering angle are compared. If the changing direction of the target steering angle (1) and the changing direction of the correction steering angle are the same, the process proceeds to step S19. On the other hand, if the changing direction of the target steering angle (1) and the direction of the correction steering angle are different, step S20. Proceed to. Step S1
At 9, a correction value for correcting the steering reaction force is obtained. The steering reaction force is corrected according to the corrected steering angle. For example, as shown in FIG. 7, a correction coefficient (1) that changes according to the corrected steering angle is used. Here, the correction coefficient (1) increases with the corrected steering angle in a region where the corrected steering angle is small,
In a region where the corrected steering angle is large, a substantially constant value (for example, approximately 0.5) is shown regardless of the change in the corrected steering angle. As shown in the following equation (1), the correction value of the steering reaction force is determined by multiplying the correction coefficient (1) by the steering angular velocity.

Steering reaction force correction amount (correction value) = steering angular velocity × correction coefficient (1) (1) Next, in step S21, the CPU 34 causes the value of the steering reaction force correction amount in step S17. In addition to the calculated steering reaction force, a final target steering reaction force is calculated, and the process proceeds to step S22. Where the steering wheel 1
The steering reaction force is corrected in accordance with the steering angular velocity, which is the operation speed of No. 3, so that the steering reaction force does not change while the steering is being held, while the correction steering is attempted. In addition, the effect of correcting the steering reaction force is obtained. Therefore, if the correction steering is not performed, the driver
There is no sense of discomfort.

In the process of step S18, the change direction coincidence detection function in the controller 30 detects that the change direction of the target rudder angle before correction and the change direction of the corrected rudder angle match. The processing in steps S19 and S21 is changed by the change direction coincidence detection function by the target steering reaction force correction function for correcting the target steering reaction force based on the corrected steering angle that the controller 30 has. This is done by correcting the target steering reaction force in the increasing direction when it is detected that the directions match.

On the other hand, in step S20, as a process of not correcting the steering reaction force, the value of the steering reaction force correction is set to 0 so that the addition to the steering reaction force performed in step S21 is eliminated. A final target steering reaction force that has not been substantially corrected is obtained, and the process proceeds to step S22. In step S22, the command current value to the reaction force motor 12 is determined based on the target steering reaction force. Next, in step S23, the CPU 34 controls the command current value and the detected current value so that the current value (detected current value) output to the reaction force motor 12 detected by the current sensor matches the determined command current value. The PWM duty is determined according to the deviation between and. For example, a predetermined value is used for the steering counter gain.

Then, the second driver 36 is turned on / off by the determined PWM duty to drive the steering motor 7. That is, the reaction motor 12 is driven so as to obtain the deviation between the target steering angle and the actually measured turning angle and reduce the deviation. Then, the processes of steps S11 to S24 are repeatedly executed at predetermined time steps.

The controller 30 drives the reaction force motor 12 by the above processing procedure. In the drive control processing of the steering motor 7 shown in FIG. 3, the yaw rate according to the steering angle of the steering wheel 13 is calculated as the target yaw rate (step S3), and the target steering angle is determined so as to match the target yaw rate ( The stepping motor 7 is driven based on the step S6) (steps S7 to S10). As a result, the vehicle turns in the direction intended for the turning motion by the driver's steering operation.

In such control, when the front and rear tires are gripping and traveling, the target steering angle becomes a simple function of the steering angle, and the steering angle always corresponds to the steering angle.
However, when the tire changes from the grip state to the slip state before, after, or before and after, the yaw rate changes even if the steering angle is constant. Therefore, in the process shown in FIG. 3, the correction steering is performed so as to suppress the change in the yaw rate (steps S5 and S6), that is, the correction operation is performed by the yaw rate feedback, whereby the tire is in the grip state. Even if the vehicle changes from the slip state to the slip state, the vehicle behavior can be stabilized without requiring the driver to make a correction steering.

On the other hand, in the processing for driving the reaction force motor 12 shown in FIG. 5, when the steering direction is corrected and the direction of the corrected steering angle coincides with the direction of the target steering angle (1). Is the steering reaction force (steps S11 to S17
In the case where the reaction force corresponding to the corrected steering angle is added to the steering reaction force obtained in step S18 to step S21 and the steering reaction force corresponding to the corrected steering angle is added to the steering reaction force, and the correction steering is not performed. The steering reaction force is made larger than that of the steering wheel 13 so that the rotating operation of the steering wheel 13 becomes heavy. That is, when the direction of the corrected rudder angle and the direction of the target rudder angle (1) are the same, it is assumed that the driver performs the correction steering, and the rotation operation of the steering wheel 13 is heavy. .

As a result, for example, it is possible to prevent the driver from habitually making a correction steering without a clear intention. Further, even if the vehicle attitude changes, the driver can sense that the vehicle is going to move in the intended direction by the fact that the steering operation is heavy, so that
There is also an effect that the driver who recognizes that the correction steering is not necessary stops the correction steering.

On the other hand, when a vehicle behavior occurs, when a skilled driver habitually attempts to correct the vehicle behavior and tries to make a correction steering, that is, a steering operation with a clear turning intention. Is performed, the steering operation is heavy but the steering wheel 13
Since the rotation operation of is possible, the driver can change the turning motion by operating the steering with a force sufficient to overcome it.

On the other hand, when the steering wheel is steered in the opposite direction to the corrected steering angle, the steering reaction force is not corrected (step S18 to step S20). This is because it is apparently not the correction steering, and therefore it can be determined that the steering is based on the driver's clear intention. As mentioned above,
The steering control device according to the first embodiment performs appropriate correction steering and extracts only the steering operation based on the driver's clear steering intention, while eliminating unnecessary steering operation.

(2) Second Embodiment Next, a steering control device according to a second embodiment will be described. The steering control device according to the second embodiment has the same configuration as that of the steering control device according to the first embodiment unless otherwise mentioned, and the controller 30 has the processing control content of the first embodiment. It is different from that of the steering control device of the embodiment.

That is, the steering control device of the first embodiment makes the operation reaction force heavy when performing the correction steering (steps S18 to S21),
Instead, the steering control device according to the second embodiment makes the steering gain low when performing the correction steering. Hereinafter, the processing content of the controller 30 will be specifically described with reference to FIGS. 7 and 8. First, the processing procedure for driving the steering motor 7 will be described using the flowchart shown in FIG. 7.

First, in step S31, when the steering wheel 13 is operated during traveling, as in the process of step S1, the first steering angle sensor 23 is operated.
Thus, the detected value corresponding to the rotation angle of the steering wheel 13 is read into the CPU 34 via the UPP 32. next,
In step S2, the CPU 34 calculates the target value of the yaw rate intended by the driver from the steering angle. The target value of the yaw rate is, for example, a mathematical model of the vehicle described inside the controller 30 (using a predetermined program), as in the case of the steering control device according to the first embodiment. The yaw rate obtained by inputting the steering angle and the vehicle speed is obtained as the target yaw rate.

Next, in step S33, the actual yaw rate of the vehicle is read from the yaw rate sensor 27 into the CPU 34 via the A / D conversion circuit 33, similarly to the processing in step S4, and then in step S34, Similar to the process in step S5, the CP
By U34, the yaw rate of this vehicle is compared with the target yaw rate, and the corrected steering angle according to the deviation from the target yaw rate is calculated.

Next, in step S35, the CPU 3
4, the steering angle change direction read in step S31 is compared with the corrected steering angle direction. Here, when the steering angle change direction and the corrected steering angle direction are the same,
If the steering angle changing direction and the corrected steering angle direction are different, the process proceeds to step S36. Processing after step S36 (steps S36 to S)
In 38), the CPU 34 corrects the steering gain to obtain the target steering angle. Specifically, the target steering angle is calculated as follows.

First, in step S36, the target steering angle (1) is fixed so that it is independent of the change in the steering angle. Next, in step S37, the steering gain is corrected according to the corrected steering angle. The steering gain is corrected, for example, by using the correction coefficient (1) as shown in the following equation (2).
The value obtained by subtracting the correction coefficient (1) from 1 is multiplied by the steering gain to obtain.

Steering gain (after correction) = (1-correction coefficient (1)) × steering gain (before correction) (2) For example, the steering gain after correction is always corrected by this correction of the steering gain. It is less than the previous steering gain. Next, in step S38, using the corrected steering gain,
A value obtained by multiplying the change in the steering angle from the time when the target steering angle (1) is fixed by the corrected steering gain is added to the fixed target steering angle (1), and the corrected steering angle is further calculated. The target rudder angle is calculated by adding. In this way, the steering gain is corrected to obtain the target steering angle, and the process proceeds to step S41. The process in step S38 is a calculation using the steering angle for obtaining the target steering angle, and the process is performed to change the calculation according to the corrected steering angle.

In the process of step S35, the change direction coincidence detection function of the controller 30 detects that the change direction of the target rudder angle before correction and the change direction of the corrected rudder angle match. The processing in step S19, step S37, and step S38 is performed by the target steering angle calculation content correction function that corrects the calculation content of the target steering angle calculation function based on the corrected steering angle that the controller 30 has. , When the change direction coincidence detection function detects that the change directions are coincident with each other, the calculation content is corrected such that the change in the target steering angle with respect to the change in the steering angle becomes smaller than in other cases. It was done by doing. Here, the case other than that means the case where the calculation contents are not corrected in this way.

On the other hand, in the processing after step S39 (steps S39 and S40), the CPU 34 obtains the target steering angle by using the steering gain which is not corrected. Specifically, the target steering angle is calculated as follows. First, in step S39, in step S2
Similar to the processing in (1), the pinion rotation angle as the steering angle of the steering wheel 13 is obtained, and this steering angle is multiplied by the steering gain to obtain the target steering angle (1). Then, in step S40, the target rudder angle is obtained by adding the corrected rudder angle to the target rudder angle (1) as in the process in step S6. In this way, the target steering angle is obtained, and the process proceeds to step S41.

The processes in and after step S41 are the same as those in steps S7 to S10,
That is, in step S41, the steering angle sensor 21
The pinion rotation angle detected by the CPU 34 is read into the CPU 34, and in step S42, the CPU 34 determines the command current value to the steering motor 7 according to the deviation between the read steering angle and the target steering angle, and in step S43. , PWM duty corresponding to the deviation between the command current and the detected current so that the current value (detected current value) output to the steering motor 7 detected by the current sensor matches the determined command current value by the CPU 34. Then, in step S44, the second driver 36 causes the PW
The turning motor 7 is turned on / off by the M duty.
Are driving.

Then, the processes of steps S31 to S44 are repeatedly executed at predetermined time steps. The controller 30 drives the steered motor 7 through the processing procedure as described above. On the other hand, the processing procedure for driving the reaction force motor 12 is as shown in the flowchart in FIG. In the process for driving the reaction force motor 12, steps S18 to S2 shown in FIG. 5 are performed.
While the steering reaction force at 0 is not corrected, other processing (step S11 to step S16, step S21 to
Similar processing is performed in step S24).

The steering control device according to the second embodiment is configured so that the steering motor 7 and the reaction force motor 1 are processed by the above processing procedure.
2 drive is controlled. Steering motor 7 shown in FIG.
In the drive control process of 1, when the steering angle changing direction is the same as the correction steering angle changing direction, the steering gain is corrected,
The correction gain is equal to or lower than the correction gain before correction (step S37),
The target steering angle is calculated using the steering gain (step S3
8), and based on that, drive control of the steering motor 7 is performed (steps S41 to S44). That is, when the direction of change in the corrected steering angle and the direction of change in the steering angle match, the gain for steering is reduced. This slows the reaction of the vehicle behavior to the steering operation.

Therefore, the vehicle behavior does not change to the extent that the driver habitually corrects and steers the vehicle. Further, even if the vehicle attitude changes, the driver can detect that the vehicle tries to move in the intended direction because the reaction of the vehicle behavior is delayed, which eliminates the need for correction steering. There is also an effect that the driver who has sensed that stops the corrective steering.

On the other hand, when the vehicle behavior changes, when a trained driver habitually attempts to correct the vehicle behavior and tries to make a correction steering, that is, a steering operation with a clear turning intention. If the steering gain is low, the steering wheel 13 can be rotated even though the steering gain is low. Therefore, the driver supplements the shortage due to the low steering gain, and further turns the steering wheel 13. The turning motion can be changed by steering.

As described above, the steering control device according to the second embodiment performs appropriate correction steering and extracts only the steering operation based on the driver's clear steering intention, while performing unnecessary steering operation. Can be eliminated. Further, in the above-described process, when the direction of change of the steering angle matches the direction of the corrected steering angle, the target steering angle (1) determined by the steering angle is fixed (step S36), and the steering angle from that time is changed. The value obtained by multiplying the change by the steering gain is added to the fixed target steering angle (1). By doing so, the target steering angle does not change unless the steering gain changes. On the other hand, when the steering gain changes, the gain changes only with respect to the deviation from the time when the gain changes. Therefore, the steering gain can be changed only within the range of the corrected steering angle. As a result, it is possible to prevent the entire steering gain from being lowered by simply setting the steering gain to be small, and to change the turning angle at that time.

Further, in the equation (2), the correction coefficient (1) having the relationship shown in FIG. 6 between 1 and the corrected steering angle.
The steering gain after correction is obtained by multiplying the steering gain by the value obtained by subtracting. Accordingly, when the corrected steering angle is small, the steering gain correction coefficient becomes 0, and the value obtained by subtracting the correction coefficient from 1 remains 1, so that the steering gain does not change. When the corrected steering angle increases from 0, the steering gain correction coefficient increases, so the steering gain decreases. However, when the corrected steering angle reaches a certain value or more, the steering gain correction coefficient becomes a constant value and does not become a correction coefficient less than that value.

As described above, when the corrected steering angle is generated, the steering gain is reduced, and thus the vehicle response gain with respect to the steering angle can be reduced. Further, in a region where the corrected steering angle is small, the correction amount of the steering gain is reduced, and in a region where the corrected steering angle is large, the correction amount is increased with a certain limit so that the steering amount increases as the corrected steering angle increases. It is possible to prevent the reaction from becoming extremely slow while allowing the reaction to.

The embodiments to which the present invention is applied have been described above. However, the present invention is not limited to being applied to the above-described embodiments. In the above-described first embodiment, as shown in the equation (1), the correction amount of the steering reaction force is obtained by multiplying the steering angular velocity by the correction coefficient (1) determined according to the correction steering. . However, the present invention is not limited to this, and the correction amount of the steering reaction force may be obtained by multiplying the correction coefficient (2) determined according to the vehicle speed as shown in the following formula (3).

Steering reaction force correction amount = correction coefficient (1) × correction coefficient (2) × steering angular velocity (3) For example, the correction coefficient (2) is used in a region where the vehicle speed is low as shown in FIG. In a region where the vehicle speed is inversely proportional to the vehicle speed and is high, the value is substantially constant regardless of the change in the vehicle speed. In this way, by incorporating the vehicle speed as a factor in the correction of the steering reaction force, the steering reaction force is corrected in consideration of the vehicle speed, so that a more natural correction is performed.

Further, in the above-described second embodiment, as shown in the equation (2), the steering gain is corrected by using the correction coefficient (1) determined according to the corrected steering. However, the present invention is not limited to this, and as shown in the following formula (4), the correction amount of the steering gain may be corrected by using a correction coefficient determined according to the vehicle speed. For example, as the correction coefficient determined according to the vehicle speed, the correction coefficient (2) shown in FIG. 10 is used.

Steering gain (after correction) = (1-correction coefficient (1) × correction coefficient (2)) × steering gain (before correction) (4) Thus, the vehicle speed is a factor in the correction of the steering gain. Since the steering gain is corrected in consideration of the vehicle speed, a more natural correction can be performed. Further, in the above-described embodiment, the case where the steering gain is corrected by the correction of the calculation content has been described as an example of correcting the calculation content of the target turning angle calculation function based on the corrected steering angle. However, the present invention is not limited to this, and other variables may be corrected by correcting the calculation content. That is, for example, the steering is slowed down in response to the driver's response to the correction steering, and at the same time, a variable capable of notifying the driver that the correction steering is being performed is corrected.

Further, it is also possible to carry out a process in which the above-described first embodiment and second embodiment are combined. That is, the steering reaction force is set to be heavy and the steering gain is set to be low. Further, in the above embodiment, the corrected steering angle is obtained based on the yaw rate, but the lateral acceleration may be used instead, or both the yaw rate and the lateral acceleration may be used to obtain the corrected steering angle.

In the above embodiment, the target steering reaction force is obtained using the steering angle of the steering wheel 13 which is an operation amount and the yaw rate and lateral acceleration which are information indicating the vehicle state. It may be obtained using either one of the vehicle states, or may be obtained using information indicating the vehicle state other than the yaw rate and lateral acceleration.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a steering control device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a controller of the steering control device.

FIG. 3 is a flowchart showing a processing procedure for driving a steering motor performed by the controller according to the first embodiment.

FIG. 4 is a characteristic diagram showing a relationship between a vehicle speed and a yaw rate correction coefficient.

FIG. 5 is a flowchart showing a processing procedure for driving a reaction force motor performed by the controller according to the first embodiment.

FIG. 6 is a characteristic diagram showing a relationship between a corrected steering angle and a correction coefficient (1).

FIG. 7 is a flowchart showing a processing procedure for driving a steering motor performed by the controller according to the second embodiment.

FIG. 8 is a flowchart showing a processing procedure for driving a reaction force motor performed by the controller in the second embodiment.

FIG. 9 is a characteristic diagram showing a relationship between a vehicle speed and a correction coefficient (2).

[Explanation of symbols]

1a, 1b wheels 7 Steering motor 12 Reaction force motor 13 steering wheel 21 Steering angle sensor 22 Rack stroke sensor 23, 24 Steering angle sensor 25 Steering torque sensor 26 Lateral acceleration sensor 30 controller 31 Processing Unit 32 UPP 33 A / D conversion circuit 34 CPU 35,36 driver

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B62D 137: 00 B62D 137: 00

Claims (11)

[Claims] 1. A steering input device including a steering wheel, a steering device which is mechanically uncoupled from the steering input device and steers steered wheels, and a driving force is applied to the steering device. A steering actuator, a steering angle detection means for detecting a steering angle of the steering wheel, a steering angle detection means for detecting a steering angle of the steered wheels, and a target steering angle based on the steering angle. Target turning angle calculation means,
A steering control unit that drives the steering actuator so that the steering angle approaches the target steering angle, a steering reaction force actuator that applies a steering reaction force to the steering input device, and an actual vehicle state is detected. Vehicle state detecting means, target steering reaction force calculating means for calculating a target steering reaction force based on the steering angle and the actual vehicle state, and driving the steering reaction force actuator based on the target steering reaction force. Steering reaction force control means for causing the vehicle state expected value detection means for detecting the vehicle state expected by the driver based on the steering angle,
Corrected turning angle calculation means for obtaining a corrected turning angle such that the actual vehicle state approaches the vehicle state expected by the driver, and a target turning angle for correcting the target turning angle based on the corrected turning angle. A steering control device comprising: a steering angle correction means; and a target steering reaction force correction means for correcting the target steering reaction force based on the corrected turning angle. 2. A steering input device including a steering wheel, a steering device which is mechanically uncoupled from the steering input device and steers steered wheels, and a driving force is applied to the steering device. A steering actuator, a steering angle detection means for detecting a steering angle of the steering wheel, a steering angle detection means for detecting a steering angle of the steered wheels, and a target steering angle based on the steering angle. Target turning angle calculation means,
A steering control unit that drives the steering actuator so that the steering angle approaches the target steering angle, a steering reaction force actuator that applies a steering reaction force to the steering input device, and an actual vehicle state is detected. Vehicle state detecting means, target steering reaction force calculating means for calculating a target steering reaction force based on the steering angle and the actual vehicle state, and driving the steering reaction force actuator based on the target steering reaction force. Steering reaction force control means for causing the vehicle state expected value detection means for detecting the vehicle state expected by the driver based on the steering angle,
Corrected turning angle calculation means for obtaining a corrected turning angle such that the actual vehicle state approaches the vehicle state expected by the driver, and a target turning angle for correcting the target turning angle based on the corrected turning angle. In a steering control device including a steering angle correction means, a target steering angle calculation content correction means for correcting the calculation content of the target steering angle calculation means based on the corrected steering angle is provided. Steering control device. 3. A steering input device including a steering wheel, a steering device which is mechanically uncoupled from the steering input device and steers steered wheels, and a driving force is applied to the steering device. A steering actuator, a steering angle detection means for detecting a steering angle of the steering wheel, a steering angle detection means for detecting a steering angle of the steered wheels, and a target steering angle based on the steering angle. Target turning angle calculation means,
A steering control unit that drives the steering actuator so that the steering angle approaches the target steering angle, a steering reaction force actuator that applies a steering reaction force to the steering input device, and an actual vehicle state is detected. Vehicle state detecting means, target steering reaction force calculating means for calculating a target steering reaction force based on the steering angle and the actual vehicle state, and driving the steering reaction force actuator based on the target steering reaction force. Steering reaction force control means for causing the vehicle state expected value detection means for detecting the vehicle state expected by the driver based on the steering angle,
Corrected turning angle calculation means for obtaining a corrected turning angle such that the actual vehicle state approaches the vehicle state expected by the driver, and a target turning angle for correcting the target turning angle based on the corrected turning angle. In a steering control device including a steering angle correction means, a target steering reaction force correction means for correcting the target steering reaction force based on the corrected steering angle, and the target steering angle based on the corrected steering angle. A target steering angle calculation content correction means for correcting the calculation content of the angle calculation means, and a steering control device. 4. The target steering reaction force correction is provided with change direction coincidence detection means for detecting that the change direction of the target steered angle before correction coincides with the change direction of the corrected steered angle. The means is adapted to correct the target steering reaction force in the increasing direction when the changing direction coincidence detecting means detects that the changing directions coincide with each other. Item 3. The steering control device according to item 1 or 3. 5. A change direction coincidence detection means for detecting that the change direction of the target turning angle before correction and the change direction of the corrected turning angle match each other, and the target turning angle calculation When the change direction coincidence detection unit detects that the change directions match each other, the content correction unit compares the target turning angle with respect to the change in the steering angle as compared with the other cases. 4. The steering control device according to claim 2, wherein the calculation content is corrected so that the change becomes small. 6. The target steering reaction force correction means is adapted to determine a correction amount of the target steering reaction force based on a steering angular velocity. Steering control device. 7. The steering control device according to claim 1, wherein the target steering reaction force correction means changes the degree of correction according to the vehicle speed. 8. The steering control device according to claim 2, wherein the target turning angle calculation content correction means changes the degree of correction according to the vehicle speed. 9. The steering control device according to claim 1, wherein the vehicle state is a yaw rate. 10. The steering control device according to claim 1, wherein the vehicle state is a lateral acceleration of the vehicle. 11. The vehicle state is both a yaw rate and a lateral acceleration of the vehicle.
The steering control device according to claim 8.