JP4501473B2 - Vehicle travel control device - Google Patents

Description

  The present invention relates to a vehicle steering control device, and more specifically, a steering means for turning a steering wheel relative to a steering input means operated by a driver, and a steering auxiliary force for generating a steering auxiliary force. The present invention relates to a vehicle steering control device having a generating means and a control means for controlling a turning means and a steering assist force generating means.

As one of steering control devices for vehicles such as automobiles, a steering gear ratio variable device that steers steering wheels relative to a steering wheel operated by a driver, for example, as described in Patent Document 1 below. A steering means such as an electric power steering device that generates a steering assist force, and a control means for controlling the steering assist force generating means and the steering assist force. 2. Description of the Related Art Conventionally, a vehicle steering control device configured to control a steering gear ratio and a steering assist force according to a vehicle speed is known.
JP 2003-320948 A

  Generally, a steering means such as a steering gear ratio variable device rotates a steering wheel when it is necessary to automatically steer a steered wheel by control, such as correction steering for preventing lane departure of a vehicle. The steering wheel can be automatically steered and the steering angle of the steering wheel can be automatically corrected, but it is inevitable that a deviation occurs between the neutral position of the steering wheel and the straight position of the steering wheel. Therefore, the deviation of the neutral position must be corrected appropriately. Also, when the steering wheel is steered by the steering means, the reaction force is transmitted to the steering wheel, so that the driver does not feel the reaction force due to the steering of the steering wheel to correct the steering wheel or to cancel the neutral position deviation. In order to achieve this, complicated control is required to cancel the reaction force by means of assisting steering force generation means such as an electric power steering device.

  Conversely, according to the steering assist force generating means such as the electric power steering device, the steering wheel can be steered without any deviation between the neutral position of the steering wheel and the straight position of the steering wheel. As the wheels are steered, the steering wheel rotates unnecessarily, and it is inevitable that the driver feels bothersome. Further, in order to avoid this problem, if the steering wheel is not steered by the steering assist force generating means as a dead zone when the required turning amount of the steering wheel is small, the necessary turning amount of the steering wheel is smaller than the dead zone region. The steered wheels are steered greatly by the steering assist force of the rudder assist force generating means at the stage when it becomes larger, and the steering wheel rotates unnecessarily large at this time and the driver Feeling anxiety is inevitable.

  As described above, since the steering means and the steering assist force generating means have advantages and disadvantages, respectively, when turning a steered wheel, the advantages of both means can be utilized and problems caused by the disadvantages can be avoided as much as possible. Although it is preferable, in the conventional steering control device as described above, there has not been a sufficient examination on the proper use of these based on the characteristics of the steering means and the steering assist force generating means. There is room for improvement.

  The present invention has been made in view of the above-described problems in a conventional steering control device having a steering means such as a steering gear ratio variable device and a steering assist force generating means such as an electric power steering device. The main problem of the present invention is that the degree of contribution of both means to the steering wheel steering is changed based on the characteristics of the steering means and the steering assist force generating means when turning the steering wheel. Thus, it is possible to reduce the possibility that the driver feels bothersome and uneasy, to reduce the fluctuation of the reaction force caused by turning the steered wheels, and to reduce the neutral position shift amount and the correction amount.

According to the present invention, the main problems described above are the steering means that can steer the steering wheel relative to the steering input means that is operated by the driver, and the steering assist force that can steer the steering wheel. a steering assist force generating means capable of generating a calculates the steering angle correction amount of the steering wheel according to the running state of the vehicle, controlling the steering means and the steering assist force generating means on the basis of the steering angle correction amount a vehicular steering control apparatus and a control means for the control means, the front when the steering angle correction amount of size is small compared to when the magnitude of the previous SL steering angle correction amount Kikaji vehicle steering control apparatus than the contribution degree of the turning means for the steering of the steering wheel based on the angular correction amount to the contribution degree of the steering assist force generating means and said relatively high camphor Rukoto ( Or the steering input means operated by the driver. Relatively steering wheel capable turning a steering means, the steering assist force generating means capable of generating steering possible steering assist force of the steering wheel, the steering of the steering wheels according to the running state of the vehicle and calculating the angular correction amount, a vehicle steering control apparatus and a control means for controlling the steering means and the steering assist force generating means on the basis of the steering angle correction amount, wherein, prior Kikaji If the magnitude of the angular correction amount is equal to or less than the reference value, the by controlling the steering means based on prior Kikaji angle correction amount without turning the steering wheel by the steering assist force generating means When the steering wheel is steered and the magnitude of the steering angle correction amount is larger than the reference value, the steering assist is performed based on the steering angle correction amount without turning the steering wheel by the steering means. The steering wheel is steered by controlling the force generating means. Steering means for turning a steering wheel relative to a steering control device for a vehicle (configuration of claim 2) or a steering input means operated by a driver, and the steering wheel can be steered Steering assist force generating means capable of generating a sufficient steering assist force, a steering angle correction amount of the steered wheel is calculated according to a traveling state of the vehicle, and the steering means and the steering assist force are calculated based on the steering angle correction amount. A vehicle steering control device having a control means for controlling the generating means, wherein the control means detects a shift in a correspondence relationship between an operation position of the steering input means and a steering angle of the steered wheels by a driver. When the deviation reduction control to be reduced by the steering of the steering wheel by the means is performed, when the steering direction of the steering wheel by the steering auxiliary force generation means is the same as the direction of the deviation, the steering auxiliary force generation means The steering direction of the steered wheel is forward This is achieved by a vehicle steering control device (configuration of claim 6) characterized in that the turning speed of the steered wheels by the turning means is made lower than when the direction of deviation is different.

According to the present invention, in major problems described above in order to effectively achieve, in the structure of the claim 1 or 2, before Kikaji angle correction amount in lane vehicle is traveling It is comprised so that it may be the rudder angle correction amount for correcting the position of a driving path width direction (structure of Claim 3).

According to the invention, to the aspect of the effective, in the structure of the claim 1 or 2, before Kikaji angle correction amount a vehicle to modify the vehicle orientation relative to the lane It is comprised so that it may be the rudder angle correction amount for making it drive | work along a lane (structure of Claim 4).

  According to the present invention, in order to effectively achieve the main problems described above, in the configuration according to any one of claims 1 to 4, the control means includes an operation position of the steering input means by the driver and the steering wheel. The steering direction of the steered wheels by the steering assist force generating means is the direction of the deviation when performing the shift reduction control for reducing the shift of the correspondence relationship with the steering angle of the steered wheels by the steered means. When the steering direction of the steering wheel by the steering assist force generating means is different from the direction of deviation, the steering speed of the steering wheel by the steering means is reduced. (Structure of claim 5).

According to this configuration 1, the operation is the steering angle correction amount of a steering wheel in accordance with the running condition of the vehicle, steering means and the steering assist force generating means based on the steering angle correction amount is controlled. Contribution degree steering assist force of the steering means for the steering of the steerable wheels based on the steering angle correction amount than when the magnitude of the steering angle correction amount when the steering angle correction amount of size, especially a small It is made relatively higher than the contribution degree of the generating means. Therefore when a small size of the steering angle correction amount is relatively small steering amount of the steering wheel by the steering assist force generating means, the steering input means is driven thereby due to the operation of the steering assist force generating means This reduces the risk of annoying the driver. When or is greater steering angle correction amount of size was relatively small steering amount of the steering wheel by turning means, thereby the amount of deviation of the neutral position due to turning of the steering wheel by turning means and It is possible to reduce the amount of fluctuation of the reaction force accompanying the correction.

In the above-described configuration according to claim 2, the operation is the steering angle correction amount of a steering wheel in accordance with the running condition of the vehicle, steering means and the steering assist force generating means based on the steering angle correction amount is controlled. Especially when the size of the steering angle correction amount is less than the reference value the steering wheel by controlling the steering means based on the steering angle correction amount is steered, if the magnitude of the steering angle correction amount is larger than the reference value The steering wheel is steered by the control of the steering assist force generating means based on the steering angle correction amount. And steering the steerable wheels, thereby steering input means due to the operation of the steering assist force generating means is driven by only the steering means when the size of the steering angle correction amount is less than the reference value in accordance It is possible to reliably prevent the driver from feeling troublesome. Also if the steering angle correction amount of size is larger than the reference value is steered only by the steering wheel steering assist force generating means, the neutral position thereby due to the turning of the steering wheel by turning means It is possible to reliably prevent the deviation amount and the fluctuation amount of the reaction force accompanying the correction from becoming large. In addition, the return control amount for reducing the shift of the neutral position can be reduced and the return control can be completed promptly as compared with the case where the steered wheels are steered by the steering means.

In the above-described configuration according to claim 3, since the steering angle correction amount is the steering angle correction amount for correcting the position of the in the traveling path width direction in lane vehicle is traveling, at the lane If the position of the vehicle in the road width direction is different from the original position, the steering wheel is automatically corrected and steered to ensure that the position in the road width direction in the lane in which the vehicle is traveling is It can be kept in a position where it should be.

In the above-described configuration according to claim 4, since the steering angle correction amount is the steering angle correction amount for running along the lane the vehicle to modify the vehicle orientation relative to the lane, the vehicle direction is originally for lane If the direction is different from the desired direction, the steered wheels are automatically corrected and steered to correct the direction of the vehicle to the original direction, and the vehicle can be reliably driven along the lane.

  According to the fifth aspect of the present invention, the shift reduction control is performed to reduce the shift of the correspondence relationship between the operation position of the steering input means by the driver and the steering angle of the steered wheels by turning the steered wheels by the steered means. At this time, when the steering direction of the steered wheels by the steering assist force generating means is the same as the direction of the deviation, compared to when the steered direction of the steered wheels by the steering assist force generating means is different from the direction of the deviation, Since the turning speed of the steered wheels by the turning means is lowered, it is possible to obtain the effect by the configuration of the first to fourth aspects, and the turning direction of the steered wheels by the steering assist force generating means is different from the direction of the deviation. If the difference is the same and the deviation can be resolved at an early stage, the steering speed of the steered wheels by the steering means is relatively lowered, and the reaction force caused by the steered steering of the steered wheels is suddenly increased. Fluctuations and driving due to this If the steering direction of the steered wheels by the steering assist force generating means is different from the direction of the deviation and it takes time to eliminate the deviation, the rolling assistance can be surely reduced. The shift speed of the steered wheels by the rudder means can be made relatively high to eliminate the shift early, and the driver's steering request can be satisfied early.

  According to the sixth aspect of the present invention, deviation reduction control is performed to reduce the deviation of the correspondence between the operation position of the steering input means by the driver and the steering angle of the steering wheel by turning the steering wheel by the steering means. At this time, when the steering direction of the steered wheels by the steering assist force generating means is the same as the direction of the deviation, compared to when the steered direction of the steered wheels by the steering assist force generating means is different from the direction of the deviation, Since the turning speed of the steered wheels by the turning means is lowered, the steering direction of the steered wheels by the steering assist force generating means is the same as the direction of the deviation as in the case of the configuration of the fifth aspect. If the problem can be resolved at an early stage, the steering speed of the steered wheels by the steered means is relatively lowered, and the reaction force caused by the steered wheels steered by the steered means is abruptly fluctuated. To ensure that the driver feels uncomfortable When the steering direction of the steered wheels by the steering assist force generating means is different from the direction of the deviation and it takes time to eliminate the deviation, the steering speed of the steered wheels by the steering means is relatively Therefore, the shift can be eliminated early, and the driver's steering request can be satisfied early.

[Preferred embodiment of problem solving means]
According to one preferable aspect of the present invention, in the configuration of the first to sixth aspects, the steering means steers the steering wheel relative to the steering operator operated by the driver. configured Ru steering allow der steering wheel independently of the steering operation of the driver (the preferred embodiment 1).

  According to another preferred aspect of the present invention, in the configuration of the first to sixth aspects, the steering assist force generating means is configured to be an electric power steering device that generates a steering assist torque (preferably). Aspect 2).

According to the aspect of the present invention, in the configuration of the first aspect, the control means the total steering angle correction amount of the steering wheel is calculated according to the running state of the vehicle, the total steering of the steering wheel When the angle correction amount is small, the total steering angle correction amount of the steered wheels is at a predetermined distribution ratio in which the distribution ratio to the steering means is higher than when the total steering angle correction amount of the steered wheels is large. the configured to allocate to the I that the steering angle correction amount by that the steering angle correction amount to the turning means and the steering assist force generating means (the preferred embodiment 3).

According to another preferred aspect of the present invention, in the configuration according to claim 1 or 2, the reference value is variably set according to the vehicle speed so as to be smaller when the vehicle speed is high than when the vehicle speed is low. (Preferred aspect 4).

According to another preferred aspect of the present invention, in the configuration of claim 5 or 6, the control means steers based on the steering angle correction amount when the steering angle correction amount is larger than a reference value. The steering wheel is steered by the control of the auxiliary force generation means and the shift reduction control is performed (preferred aspect 5).

  The present invention will now be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram showing a vehicle steering control device according to the present invention applied to a vehicle equipped with an automatic steering device and an electric power steering device.

  In FIG. 1, 10FL and 10FR respectively indicate the left and right front wheels of the vehicle 12, and 10RL and 10RR respectively indicate the left and right rear wheels of the vehicle. The left and right front wheels 10FL and 10FR, which are the steering wheels, are driven via a rack bar 18 and tie rods 20L and 20R by a rack-and-pinion type electric power steering device 16 driven in response to an operation of the steering wheel 14 by a driver. Steered.

  In the illustrated embodiment, the electric power steering device 16 is a rack coaxial type electric power steering device, and converts the electric motor 22 and the rotational torque of the electric motor 22 into a force in the reciprocating direction of the rack bar 18. For example, it has a ball screw type conversion mechanism 24 and functions as an auxiliary steering force generator that reduces the driver's steering burden by generating an auxiliary steering force that drives the rack bar 18 relative to the housing 26. To do. The auxiliary steering force generator may be of any configuration known in the art.

  The steering wheel 14 includes an upper steering shaft 28A as a first steering shaft, a turning angle varying device 30, a lower steering shaft 28B as a second steering shaft, and a pinion shaft of the electric power steering device 16 via a universal joint 32. 34 is drivingly connected. In the illustrated embodiment, the turning angle varying device 30 is connected to the lower end of the upper steering shaft 28A on the housing 36A side, and to the upper end of the lower steering shaft 28B on the rotor 36B side. A motor 36 for turning driving is included.

  Thus, the turning angle varying device 30 rotationally drives the lower steering shaft 28B relative to the upper steering shaft 28A, so that the left and right front wheels 10FL and 10FR, which are the steering wheels, are auxiliary steered relative to the steering wheel 14. It functions as an automatic steering device that drives.

  In particular, the turning angle varying device 30 normally has a relative rotation angle of the lower steering shaft 28B with respect to the upper steering shaft 28A (simply referred to simply as a holding current that prevents relative rotation of the housing 36A and the rotor 36B is applied to the motor 36). The relative steering angle is maintained at 0). However, during automatic steering, the lower steering shaft 28B is actively rotated relative to the upper steering shaft 28A by the motor 36, whereby the left and right front wheels 10FL and 10FR are rotated as necessary. Steer automatically.

  In the illustrated embodiment, the upper steering shaft 28A is provided with a steering angle sensor 40 for detecting the rotation angle of the upper steering shaft as the steering angle θs and a torque sensor 42 for detecting the steering torque Ts. The steering shaft 28B is provided with a steering angle sensor 44 that detects the rotation angle of the lower steering shaft as the actual steering angle θa of the left and right front wheels, and outputs of these sensors are supplied to the steering control device 46. The steering control device 46 also receives a signal indicating the vehicle speed V detected by the vehicle speed sensor 48 and a signal indicating image information in front of the vehicle imaged by the CCD camera 50. The steering angle sensor 44 may be replaced with a sensor that detects the steering driving angle of the steering angle varying device 30, that is, the relative rotation angle of the lower steering shaft 28B with respect to the upper steering shaft 28A.

  A signal indicating the steering angle θa and a signal indicating the vehicle speed V are also input from the steering control device 46 to the turning angle variable control device 52 that controls the turning angle variable device 30, and the signal indicating the steering torque Ts and the vehicle speed V are set. The signal shown is also input from the steering control device 46 to an electric power steering (EPS) control device 54 that controls the electric power steering device 16. A signal indicating the steering angle θa detected by the steering angle sensor 44 is used to adjust the straight traveling positions of the left and right front wheels 10FL and 10FR to the neutral position of the steering wheel 14.

As will be described later, the steering control device 46 calculates the curvature radius R as the degree of curvature of the travel path 100 on which the vehicle 12 travels as shown in FIG. 3 based on the image information in front of the vehicle captured by the CCD camera 50. The lateral deviation Y is calculated as the amount of deviation in the road width direction of the vehicle 12 with respect to the lateral center line 104 of the lane 102 of the travel path 100, and the yaw angle φ of the vehicle 12 with respect to the lateral center line 104 of the lane 102 of the travel path 100 is calculated. And a target rudder angle correction amount Δδ (hereinafter simply referred to as a rudder angle correction amount Δδ ) for causing the vehicle 12 to travel along the lateral center line 104 of the lane 102 based on the curvature radius R, lateral deviation Y, and yaw angle φ. ) Is calculated.

  When the steering angle correction amount Δδ is less than the reference value δo (positive constant), the steering control device 46 uses the steering angle varying device 30 to change the steering angles of the left and right front wheels 10FL and 10FR to the steering angle correction amount Δδ. The target relative rotation angle θr of the lower steering shaft 28B with respect to the upper steering shaft 28A is calculated as the target automatic steering amount of the turning angle variable device 30 for performing the turning, and a command signal indicating the target relative rotation angle θr is calculated. To 52.

  The turning angle variable control device 52 maintains the relative rotation angle of the turning angle variable device 30 at 0 during normal steering by the driver. When a signal indicating the target relative rotation angle θr is input from the steering control device 46, the lower turning angle control device 52 The left and right front wheels 10FL and 10FR are automatically controlled by controlling the motor 36 of the turning angle varying device 30 based on the target relative rotation angle θr so that the steering shaft 28B rotates relative to the upper steering shaft 28A. Thus, the steering is corrected, thereby reducing the deviation of the lateral position of the vehicle with respect to the road and the deviation of the yaw angle of the vehicle with respect to the road.

  The electric power steering control device 54 calculates the auxiliary steering torque Tab for reducing the driver's steering load in accordance with the steering torque Ts and the vehicle speed V in normal times, and sets the auxiliary steering torque Tab as the target auxiliary steering torque Ta. By controlling the electric motor 22 of the electric power steering device 16 based on the auxiliary steering torque Ta, steering assist is performed to reduce the driver's steering burden.

  When the steering angle correction amount Δδ is equal to or greater than the reference value δo, the steering control device 46 corrects the steering angle correction amount Δδ for the steering angles of the left and right front wheels 10FL and 10FR by the auxiliary steering force of the electric power steering device 16. The electric power steering control device 54 calculates the sum of the auxiliary steering torque Tab and the target steering torque Tc input from the steering control device 46 as the target auxiliary steering torque Ta. By controlling the electric motor 22 of the electric power steering device 16 based on the target auxiliary steering torque Ta, the correction steering of the left and right front wheels 10FL and 10FR is assisted. Reduce the deviation of the vehicle yaw angle relative to the road.

  In particular, in the illustrated embodiment, as will be described later, when the magnitude of the steering angle correction amount Δδ is greater than or equal to the reference value δo, the steering control device 46 determines the absolute value of the deviation Δθ between the steering angle θs and the actual steering angle θa. Whether or not there is a deviation between the neutral position of the steering wheel 14 and the vehicle straight positions of the left and right front wheels 10FL and 10FR by determining whether or not is greater than or equal to a reference value θo (positive constant). When there is a neutral position shift, it is determined whether the direction of the correction steering by the electric power steering device 16 is the same as the neutral position shift direction, and both directions are the same. Sometimes the turning angle varying device 30 rotates the lower steering shaft 28B relative to the upper steering shaft 28A at a speed of Vs1 to return the neutral position deviation Δθ to substantially zero. When the control is performed and both directions are opposite, the steering angle varying device 30 rotates the lower steering shaft 28B relative to the upper steering shaft 28A at a speed Vs2 higher than the speed Vs1, thereby shifting the neutral position. Return control is performed to make Δθ substantially zero.

  Although not shown in detail in FIG. 1, the steering control device 46, the turning angle variable control device 52, and the electric power steering control device 54 have a CPU, a ROM, a RAM, and an input / output port device, respectively. May comprise a microcomputer and a drive circuit connected to each other by a bidirectional common bus. The steering angle sensors 40 and 44, the torque sensor 42, and the yaw rate sensor 50 detect the steering angles θs and θa, the steering torque Ts, and the yaw rate γ, respectively, when the vehicle is steered in the left turn direction.

  Next, a steering control routine in the embodiment will be described with reference to the flowchart shown in FIG. The control according to the flowchart shown in FIG. 2 is started by closing an ignition switch not shown in the figure, and is repeatedly executed at predetermined time intervals.

  First, in step 10, a signal indicating the steering angle .theta.s is read, and in step 20, image analysis processing known in the art is performed on the image in front of the vehicle imaged by the CCD camera 50. As shown in FIG. 3, it is determined whether or not the white line 106 of the traveling path 100 on which the vehicle 12 travels can be detected. If an affirmative determination is made, the process proceeds to step 50. When a negative determination is made, the routine proceeds to step 30.

  In step 30, it is determined whether or not there is a neutral position shift Δθ. If a negative determination is made, the process proceeds to step 110, and if an affirmative determination is made, the neutral position shift is determined in step 40. The turning angle varying device 30 is controlled by setting the value for setting the deviation Δθ to 0 as the target relative rotation angle θrt (= −Δθ) of the turning angle varying device 30, and the lower steering shaft 28B is relatively relative to the upper steering shaft 28A. By being rotationally driven at a speed of Vs0, return control for setting the neutral position shift Δθ to 0 is executed, and then the routine proceeds to step 110. The speed Vs0 may be an arbitrary speed, but is preferably higher than the speed Vs1 and lower than the speed Vs2.

  In step 50, based on the information on the travel path 100 obtained by the image analysis process, the travel path to the point 110 where the vehicle 12 arrives after the reference time Te from the current point 108 as shown in FIG. 100 is estimated, and the curvature radius R is calculated as the degree of curvature of the travel path 100 between the point 108 and the point 110 on the travel path 100 based on the estimated shape of the travel path 100.

  In step 60, the lateral deviation Y is calculated as the amount of deviation of the vehicle 12 in the width direction of the vehicle 12 with respect to the lateral center line 104 of the lane 102 of the road 100. In step 70, for example, the integrated value of the yaw rate of the vehicle. Based on the above, the yaw angle φ of the vehicle 12 with respect to the lateral center line 104 of the lane 102 of the road 100 is calculated. In step 80, the vehicle is based on the radius of curvature R, the lateral deviation Y, and the yaw angle φ of the road 100. The steering angle correction amount Δδ of the left and right front wheels for causing the vehicle 12 to travel along the lateral center line 104 of the lane 102 is calculated.

  In step 90, it is determined whether or not the absolute value of the steering angle correction amount Δδ is greater than or equal to a reference value δo (a positive constant), that is, the auxiliary steering force of the electric power steering device 16 determines the left and right front wheels 10FL and 10FR. It is determined whether or not the steering angle needs to be corrected. If an affirmative determination is made, the process proceeds to step 120. If a negative determination is made, the process proceeds to step 100.

  In step 100, the lower steering for the upper steering shaft 28A is used as the target automatic steering amount of the turning angle varying device 30 for correcting the steering angle correction amount Δδ for the steering angles of the left and right front wheels 10FL and 10FR by the turning angle varying device 30. The target relative rotation angle θrt of the shaft 28B is calculated, and a command signal indicating the target relative rotation angle θrt is output to the turning angle variable control device 52, whereby the turning angle variable device 30 changes the steering angle of the left and right front wheels. The correction amount Δδ is corrected.

  In step 110, the target turning torque Tc for correcting the steering angle correction amount Δδ for the steering angles of the left and right front wheels 10FL and 10FR by the auxiliary steering force of the electric power steering device 16 is set to 0 and the target turning is performed. A signal indicating that the rudder torque Tc is 0 is output to the electric power steering control device 54, and thereby equal to the auxiliary steering torque Tab for reducing the driver's steering load in accordance with the steering torque Ts and the vehicle speed V. By controlling the electric motor 22 of the electric power steering device 16 based on the target auxiliary steering torque Ta, normal steering assist that reduces the steering burden on the driver is performed.

  In this steering assist, the left and right front wheels are steered to eliminate the neutral position deviation Δθ in step 40 and the left and right front wheels are steered to correct the steering angle of the left and right front wheels in step 100. It is preferable that a component that counteracts the reaction force is included in the target auxiliary steering torque Ta, and fluctuations in the steering reaction force due to these steering operations are eliminated.

  In step 120, it is determined whether or not there is a shift in the neutral position, that is, whether there is a shift between the neutral position of the steering wheel 14 and the vehicle straight positions of the left and right front wheels 10FL and 10FR. If YES in step 160, the flow advances to step 160. If an affirmative determination is made, the flow advances to step 130.

  In step 130, it is determined whether or not the direction of the correction turning by the electric power steering device 16 is the same as the direction of deviation of the neutral position. If an affirmative determination is made, step 140 is performed. Then, the lower steering shaft 28B is rotationally driven relative to the upper steering shaft 28A at a speed of Vs1 by the turning angle varying device 30, thereby performing return control to make the neutral position deviation Δθ substantially zero. When a command signal is output to the turning angle variable control device 52 and a negative determination is made, in step 150, the turning angle varying device 30 causes the lower steering shaft 28B to move relative to the upper steering shaft 28A from the speed Vs1. Return to make the neutral position deviation Δθ substantially zero by rotationally driving at a higher Vs2 speed. Command signal for control is output to the steering angle variable control system 52.

  In step 160, the target steering torque Ts for correcting the steering angle correction amount Δδ for the steering angles of the left and right front wheels 10FL and 10FR is calculated by the auxiliary steering force of the electric power steering device 16, and the target steering torque Ts is calculated. Is output to the electric power steering control device 54, and the sum of the auxiliary steering torque Tab and the target turning torque Ts input from the steering control device 46 by the electric power steering control device 54 is the target auxiliary steering torque Ta. And the motor 22 of the electric power steering device 16 is controlled on the basis of the target auxiliary steering torque Ta, so that the correction steering of the left and right front wheels 10FL and 10FR is assisted, and thereby the lateral direction of the vehicle with respect to the travel path A shift in position and a shift in the yaw angle of the vehicle with respect to the travel path are reduced.

  Thus, according to the embodiment shown in the drawing, the white line 106 of the traveling road 100 can be detected, and when an affirmative determination is made at step 20, the vehicle 12 after the reference time Te from the current point 108 at step 50. The radius of curvature R of the travel path 100 to the point 110 where the vehicle reaches is calculated, and in step 60, the lateral deviation Y is determined as the amount of deviation in the travel path width direction of the vehicle 12 with respect to the lateral center line 104 of the lane 102 of the travel path 100. In step 70, the yaw angle φ of the vehicle 12 with respect to the lateral center line 104 of the lane 102 of the travel path 100 is calculated. In step 80, the radius of curvature R, lateral deviation Y, yaw of the travel path 100 is calculated. A steering angle correction amount Δδ for the left and right front wheels for causing the vehicle 12 to travel along the lateral center line 104 of the lane 102 is calculated based on the angle φ.

  When the absolute value of the steering angle correction amount Δδ is less than the reference value δo, a negative determination is made in step 90, and in step 100, the steering angles of the left and right front wheels 10FL and 10FR are set by the turning angle varying device 30. A target relative rotation angle θrt of the turning angle variable device 30 for correcting the steering angle correction amount Δδ is calculated, and a command signal indicating the target relative rotation angle θr is output to the turning angle variable control device 52, thereby turning the steering. The steering angle correction amount Δδ is corrected for the steering angle of the left and right front wheels by the angle varying device 30, thereby reducing the deviation of the lateral position of the vehicle with respect to the traveling road and the deviation of the yaw angle of the vehicle with respect to the traveling road.

  In this case, in step 110, the target steering torque Tc for correcting the steering angle correction amount Δδ for the steering angles of the left and right front wheels 10FL and 10FR is set to 0 by the auxiliary steering force of the electric power steering device 16, and the target turning A signal indicating that the rudder torque Tc is 0 is output to the electric power steering control device 54, whereby the steering by the electric power steering device 16 for correcting the rudder angle correction amount Δδ for the left and right front wheels is steered. Assist is not performed, and normal steering assist for reducing the driver's steering load is performed.

  On the other hand, when the absolute value of the steering angle correction amount Δδ is greater than or equal to the reference value δo, an affirmative determination is made in step 90, and the steering angle variable for correcting the steering angle correction amount Δδ for the steering angle of the left and right front wheels. Although the steering control by the device 30 is not performed, the target steering torque for correcting the steering angle correction amount Δδ for the steering angles of the left and right front wheels 10FL and 10FR by the auxiliary steering force of the electric power steering device 16 in step 160. Ts is calculated, and a signal indicating the target turning torque Ts is output to the electric power steering control device 54 to assist in the correction turning of the left and right front wheels 10FL and 10FR. The shift in the lateral position and the shift in the yaw angle of the vehicle with respect to the travel path are reduced.

  Therefore, according to the illustrated embodiment, when the absolute value of the steering angle correction amount Δδ is less than the reference value δo, the steering angle correction amount Δδ is corrected by the steering angle variable device 30 alone. It is possible to reliably prevent the driver from feeling troublesome due to the steering angle of the left and right front wheels being corrected and the steering wheel 14 being rotationally driven by the auxiliary steering force of the electric power steering device 16.

  Further, since a large dead zone is not set, correction of the steering angle of the left and right front wheels and rotation driving of the steering wheel 14 by the auxiliary steering force of the electric power steering device 16 are not avoided, so that the lateral direction of the vehicle with respect to the travel path Even when the positional deviation or the deviation of the yaw angle of the vehicle with respect to the travel path is small, these deviations can be reliably and effectively reduced, and the lateral deviation of the vehicle or the yaw angle of the vehicle with respect to the travel path can be reduced. The driver feels uneasy due to the fact that the steering angle of the left and right front wheels is largely corrected by the auxiliary steering force of the electric power steering device 16 and the steering wheel 14 is driven to rotate greatly when the deviation exceeds the dead zone. This can be surely prevented.

Further, according to the illustrated embodiment, when the absolute value of the steering angle correction amount Δδ is equal to or larger than the reference value δo, the steering angle of the left and right front wheels is corrected by the auxiliary steering force of the electric power steering device 16 and the turning angle is variable. since modifications of the left and right front wheels of the steering angle by the device 30 is not performed, Ru can be reliably prevented the variation of the reaction force caused by the modification of that and displacement Δθ displacement Δθ in the neutral position is increased. Further , even when the absolute value of the steering angle correction amount Δδ is equal to or larger than the reference value δo, the neutral position shift Δθ is substantially reduced as compared with the case where the steering angle of the left and right front wheels is corrected by the turning angle varying device 30. Therefore, the amount of return control for reducing to zero can be reduced, and the return control can be completed promptly.

  FIG. 4 shows the case where steering assist is not performed (A), the direction of steering assist is the same as the direction of deviation of the neutral position (B), and the direction of steering assist is opposite to the direction of deviation of the neutral position. It is explanatory drawing which shows the relationship between the direction of the shift | offset | difference of a neutral position, and the steering assist direction of an electric power steering device about (C).

  As shown in FIG. 4A, the left and right front wheels are corrected by the turning angle varying device 30 in a state where the left and right front wheels 10FL and 10FR are steered in the right turning direction with respect to the vehicle straight position of the steering wheel 14. If the steering is finished, the left and right front wheels must be controlled to return in the left turn direction to the vehicle straight ahead position.

  As shown in FIG. 4B, when the direction of the steering assist is the same as the direction of deviation of the neutral position, the steering wheel 14 is turned in the right turn direction by the auxiliary steering force of the electric power steering device 16. Since the neutral position deviation is reduced relatively quickly, the steering assist direction and the neutral position deviation direction are opposite as shown in FIG. 4C. Since the steering wheel 14 is rotationally driven in the left turning direction by the auxiliary steering force of the electric power steering device 16, it takes time to reduce the neutral position shift.

  According to the illustrated embodiment, when the absolute value of the steering angle correction amount Δδ is greater than or equal to the reference value δo and there is a neutral position deviation, the steering assist direction and the neutral position deviation direction are the same. In some cases, an affirmative determination is made in step 130, and in step 140, the lower steering shaft 28B is driven to rotate at a relatively slow speed Vs1 relative to the upper steering shaft 28A by the turning angle varying device 30. Therefore, it is possible to reliably prevent a sudden change in the behavior of the vehicle due to the right and left front wheels being steered quickly in order to eliminate the neutral position shift.

  On the other hand, when the direction of the steering assist and the direction of the neutral position shift are opposite, a negative determination is made in step 130, and in step 150, the lower steering shaft 28B is moved upward by the turning angle varying device 30. Since it is rotationally driven at a relatively high speed Vs2 relative to the steering shaft 28A, the neutral position shift can be eliminated at an early stage.

  Although the present invention has been described in detail with reference to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art.

  For example, in the above-described embodiment, when the absolute value of the steering angle correction amount Δδ of the left and right front wheels is less than the reference value δo, the steering angle of the left and right front wheels is adjusted by the steering angle variable device 30 only. When the absolute value of the steering angle correction amount Δδ is equal to or greater than the reference value δo, the steering angle of the left and right front wheels is corrected by the auxiliary steering force of the electric power steering device 16, and the steering angle variable device 30 steers the left and right front wheels. Although the angle is not corrected, for example, as shown in FIG. 5, the distribution ratio Rc with respect to the turning angle varying device 30 becomes 0 as the absolute value of the steering angle correction amount Δδ of the left and right front wheels increases. The steering angle correction amount Δδ of the left and right front wheels is distributed to the steered angle varying device 30 as RcΔδ, and is calculated as (1−Rc) Δδ to the electric power steering device 16. The amount of steering angle correction It may be corrected so that the degree of contribution of the turning angle varying device 30 to the turning of the left and right front wheels based on the steering angle correction amount becomes gradually higher as the steering angle becomes smaller.

  In the above-described embodiment, the steering angle correction amount Δδ for the left and right front wheels is a steering angle correction amount for reducing the deviation of the lateral position of the vehicle with respect to the traveling road and the deviation of the yaw angle of the vehicle with respect to the traveling road. However, the rudder angle correction amount may be an arbitrary rudder angle correction amount for preferably running the vehicle. For example, the rudder angle correction amount for reducing the deviation between the actual yaw rate of the vehicle and the target yaw rate of the vehicle, When an obstacle in front of the vehicle is detected by a radar or the like, the steering angle correction amount for avoiding the obstacle in front of the vehicle may be used.

  In the above-described embodiment, the lateral deviation Y as the amount of deviation of the vehicle 12 in the road width direction with respect to the radius of curvature R of the road 100 along which the vehicle 12 travels and the lateral center line 104 of the lane 102 of the road 100 is determined. The yaw angle φ of the vehicle 12 with respect to the lateral center line 104 of the lane 102 of the travel path 100 is calculated based on information obtained by performing image analysis processing on an image ahead of the vehicle imaged by the CCD camera 50. However, the information may be information supplied from a wireless road information providing device or a navigation device installed on the traveling road.

  Further, in the above-described embodiment, the turning angle variable control device 52 maintains the relative rotation angle of the turning angle varying device 30 at the time of normal steering by the driver, but the turning angle is variable. The device 30 can change the gear ratio according to the traveling state of the vehicle so that the ratio of the rotation angle of the lower steering shaft 28B to the rotation angle of the upper steering shaft 28A becomes smaller, for example, as the vehicle speed V increases during normal steering without automatic steering. It may be used as a device.

  Further, in the above-described embodiment, the turning angle variable device 30 is controlled by the turning angle variable control device 52, and the electric power steering device 16 is controlled by the electric power steering control device 54, and the turning angle variable control. The device 52 and the electric power steering control device 54 are controlled by the steering control device 46, but at least two of these control devices may be integrated into one control device.

It is a schematic block diagram which shows the vehicle steering control apparatus by this invention applied to the vehicle provided with the automatic steering apparatus and the electric power steering apparatus. It is a flowchart which shows the steering control routine in an Example. It is a top view which shows the driving | running | working condition at the time of turning of a vehicle. When steering assist is not performed (A), when the direction of steering assist is the same as the direction of deviation of the neutral position (B), when the direction of steering assist is opposite to the direction of deviation of the neutral position (C) FIG. 5 is an explanatory diagram showing a relationship between a neutral position shift direction and a steering assist direction of the electric power steering apparatus. 6 is a graph showing a relationship between an absolute value of a steering angle correction amount Δδ of the left and right front wheels and a distribution ratio Rc with respect to the turning angle varying device 30.

Explanation of symbols

DESCRIPTION OF SYMBOLS 16 Electric power steering apparatus 14 Steering wheel 30 Steering angle variable apparatus 40 Steering angle sensor 42 Torque sensor 44 Steering angle sensor 46 Steering control apparatus 48 Vehicle speed sensor 50 CCD camera 52 Steering angle variable control apparatus 54 Electric power steering (EPS) )Control device

Claims (6)

Steering means capable of turning the steering wheel relative to the steering input means operated by the driver, steering assistance force generating means capable of generating steering assistance force capable of turning the steering wheel, calculates the steering angle correction amount of the steering wheel according to the running state, there in vehicular steering control apparatus and a control means for controlling the steering means and the steering assist force generating means on the basis of the steering angle correction amount Te, wherein, when the magnitude of the steering angle correction amount is small the relative turning of the steering wheel based on prior Kikaji angle correction amount than when the magnitude of the previous SL steering angle correction amount vehicle steering control device according to claim Rukoto relatively high camphor than the contribution degree of the steering assist force generating means the contribution degree of the steered unit. Steering means capable of turning the steering wheel relative to the steering input means operated by the driver, steering assistance force generating means capable of generating steering assistance force capable of turning the steering wheel, The vehicle steering control device includes a control unit that calculates a steering angle correction amount of the steered wheel according to a traveling state and controls the steering unit and the steering assist force generation unit based on the steering angle correction amount. Te, wherein, prior to when Kikaji angle correction amount of size is less than the reference value, based on Kikaji angle correction amount before without turning the steering wheel by the steering assist force generating means The steering wheel is steered by controlling the steering means, and when the steering angle correction amount is larger than the reference value, the steering wheel is not steered by the steering means. The steering assist force generating means is controlled based on the steering angle correction amount. Vehicle steering control apparatus, characterized by steering the steering wheel by the. Before Symbol steering angle correction amount for vehicle according to claim 1 or 2, characterized in that a steering angle correction amount for correcting the position of the in the traveling path width direction in lane vehicle is traveling Steering control device. Before Kikaji angles modification amount is the vehicle steering control apparatus according to claim 2, characterized in that the steering angle correction amount for running along the lane the vehicle to modify the vehicle orientation relative to the lane . When the control means performs deviation reduction control for reducing the deviation of the correspondence relationship between the operation position of the steering input means by the driver and the steering angle of the steering wheel by turning the steering wheel by the steering means, When the steering direction of the steered wheel by the steering assist force generating means is the same as the direction of deviation, compared to when the steered direction of the steering wheel by the steering assist force generating means is different from the direction of deviation. The vehicle steering control device according to any one of claims 1 to 4, wherein a steering speed of the steered wheels by the steering means is lowered. Steering means capable of turning the steering wheel relative to the steering input means operated by the driver, steering assistance force generating means capable of generating steering assistance force capable of turning the steering wheel, The vehicle steering control device includes a control unit that calculates a steering angle correction amount of the steered wheel according to a traveling state, and controls the steering unit and the steering assist force generation unit based on the steering angle correction amount. The control means performs a deviation reduction control for reducing a deviation in a correspondence relationship between an operation position of the steering input means by the driver and a steering angle of the steering wheel by turning the steering wheel by the steering means. When the steering direction of the steered wheels by the steering assist force generating means is the same as the shift direction, the steered direction of the steered wheels by the steering assist force generating means is different from the shift direction. By the steering means Vehicle steering control apparatus characterized by lowering the turning speed of the steering wheel.

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