JP5194949B2 - Vehicle steering control device - Google Patents

Description

  The present invention relates to a vehicle steering control device.

  When oversteer occurs in the turning state of the vehicle, in order to stabilize the vehicle by suppressing the degree of oversteer, the steering wheel (steering wheel) is operated in the direction opposite to the yawing movement direction of the vehicle to yaw the steered wheels. It is effective to steer in the direction opposite to the direction of motion.

  Also, anti-skid control (ABS control), traction control (TCS control), etc. while the vehicle is traveling on a road surface with different friction coefficients (hereinafter referred to as “μ split road surface”) where the vehicle contacts the left and right wheels. When slip suppression control (hereinafter referred to as “μ split control”) is performed to suppress the slip of the wheel, the longitudinal force of the left and right wheels (the friction force in the acceleration / deceleration direction generated between the road surface and the tire) (Also referred to as braking / driving force)) (difference in braking force in the case of ABS control, difference in driving force in the case of TCS control). Due to the difference in the longitudinal force between the left and right wheels, a vehicle deflection (yawing motion) may occur. In order to suppress the deflection of the vehicle and stabilize the vehicle, it is effective to steer the steering wheel in the direction opposite to the yawing movement direction by operating the steering operation member in the direction opposite to the yawing movement direction of the vehicle. is there.

  The operation of the steering operation member in the direction opposite to the vehicle yawing motion direction is also referred to as “counter steer (operation)”. Hereinafter, the steering direction opposite to the vehicle yawing movement direction is also referred to as “countersteer direction”. Specifically, the “countersteer direction” is a direction in which the steering wheel is steered clockwise when viewed from the driver when the vehicle yawing movement direction is the left turn (left deflection) direction, and the vehicle yawing movement direction is clockwise. In the direction of turning (right deflection), the steering wheel is steered counterclockwise as viewed from the driver.

When oversteer occurs (that is, when the countersteer operation is necessary), the stabilizing force (stabilizing torque) for guiding or assisting the driver's countersteer operation is applied to the steering operation member in the countersteer direction. There is known an apparatus for applying to (for example, see Patent Document 1).
Japanese Patent No. 3034430

  By the way, a driver who is skilled in counter steer operation (hereinafter referred to as “skilled driver”), such as when oversteer occurs and when the vehicle is deflected due to a difference in the front-rear force between the left and right wheels, etc. When the counter steer operation is necessary, it is possible to positively perform an appropriate counter steer operation while predicting the behavior of the vehicle. Therefore, when a skilled driver drives a vehicle equipped with the device described in the above document, for example, when oversteer occurs, the skilled driver The counter-steer operation is performed while feeling a steering force smaller than a normal (expected) steering force (operation torque, road surface reaction force). As a result, a problem may arise that the skilled driver feels uncomfortable that the steering force during the counter-steer operation is reduced unexpectedly.

  The present invention has been made in order to cope with the above-described problem. When a counter-steer operation is required, a steering force (stabilizing torque) for guiding or assisting the driver's counter-steer operation is provided as a steering operation member. In the vehicle steering control device applied in the counter-steer direction, it is intended to provide a device capable of suppressing the “uncomfortable feeling that the steering force during the counter-steer operation is reduced unexpectedly” that a skilled driver learns. .

  A vehicle steering control apparatus according to the present invention includes a yawing value acquisition unit, a stabilization force calculation unit, and a force application unit. Hereinafter, these means will be described in order.

  The yawing value acquisition means acquires a yawing value that is a value corresponding to the yawing motion of the vehicle. The yawing value is, for example, an oversteer state quantity that represents the degree of oversteer of the vehicle, a difference in the longitudinal force between the left and right wheels of the vehicle, and the like.

  The stabilizing force calculating means is a stability for inducing or assisting a counter steer operation of a steering operation member operated by the driver of the vehicle to steer the steering wheel of the vehicle based on the yawing value. Calculate the stabilization force (stabilization torque). The stabilizing force is calculated, for example, by calculating the stabilizing force to zero when the yawing value is equal to or less than a predetermined value, and as the yawing value is larger than the predetermined value, the stabilization force increases with the predetermined value. The stabilization force is configured to increase from zero.

  The force applying means applies the stabilizing force to the steering operation member in a counter steer direction (a direction in which the steered wheels are steered in the counter steer direction). This guides or assists the driver's counter steering operation.

  The vehicle steering control device according to the present invention is characterized in that the stabilizing force calculating means includes counter steer value calculating means for calculating a counter steer value representing a degree of steering of the steered wheels in the counter steer direction. The stabilization force is configured to be adjusted based on the counter steer value.

  Here, the counter steer value is, for example, a counter steer achievement value that represents the degree of achievement of steering of the steered wheels in the counter steer direction. In this case, the stabilizing force is adjusted to a smaller value as the counter steer achievement value is larger. The counter steer achievement value is calculated based on a value corresponding to the actual steering angle of the steered wheel when the steered wheel is steered in the counter steer direction, for example.

  The counter steer value is, for example, a counter steer deficiency value that represents a degree of insufficient steering of the steered wheels in the counter steer direction. In this case, the stabilizing force is adjusted to a smaller value as the countersteer deficiency value is smaller. The countersteer deficiency value is, for example, a value corresponding to a target rudder angle in the countersteer direction of the steered wheel for stabilizing the vehicle calculated based on the yawing value, and an actual steerer of the steered wheel. Calculation is performed based on a comparison result (for example, deviation) with a value corresponding to a corner.

  The “value corresponding to the target rudder angle” is, for example, the target rudder angle itself, the target operation amount of the steering operation member corresponding to the target rudder angle, or the like. The “value corresponding to the actual steering angle” is, for example, the actual steering angle itself, the actual operation amount of the steering operation member corresponding to the actual steering angle, or the like. With respect to the target rudder angle, for example, a yawing moment in the counter-steer direction (stabilized yawing moment) to be applied to stabilize the vehicle based on the yawing value is calculated, and the stabilized yawing moment and the yaw moment of the vehicle are calculated. Based on the (reverse) model relating to motion, the steering angle of the steered wheels necessary to generate the stabilizing yawing moment may be calculated, and this steering angle may be set as the target steering angle.

  According to the above configuration, the stabilizing force becomes smaller as the countersteer achievement value is larger (or the countersteer deficiency value is smaller). Here, a large countersteer achievement value (or a small countersteer shortage value) means that the driver is performing an appropriate countersteer operation.

  As described above, when the skilled driver performs an appropriate counter steering operation while predicting the behavior of the vehicle (when the achievement level of the counter steering operation is large or when the shortage is small), the steering operation member is The stabilization force imparted is reduced. In other words, the degree to which the steering force (steering torque) is reduced by the stabilizing force is reduced. Therefore, it is possible to suppress the “uncomfortable feeling that the steering force during the counter-steer operation is reduced unexpectedly” that the skilled driver learns. Further, when the countersteer achievement value is small (or when the countersteer shortage value is large), that is, when the driver is not performing an appropriate countersteer operation, the stabilizing force is increased. As a result, for a driver who is not a skilled driver, the countersteer operation can be appropriately or sufficiently guided or assisted by a large stabilizing force.

  Further, in the steering control device, instead of the stabilization force calculating means adjusting the stabilization force based on the counter steer value, the force applying means performs the operation based on the counter steer value. It is determined whether or not the counter steer operation of the steering operation member has been performed by a person, and when it is determined that the counter steer operation has been performed, the stabilization force is not applied, and the counter steer operation is not performed It may be configured to apply the stabilizing force when it is determined.

  According to this, when the skilled driver performs an appropriate counter steering operation while predicting the behavior of the vehicle, the stabilizing force is not applied to the steering operation member. Therefore, it is possible to suppress the “uncomfortable feeling that the steering force during the counter-steer operation is reduced unexpectedly” that the skilled driver learns. Further, when the driver is not performing the counter steer operation, an appropriate amount of stabilizing force can be applied. As a result, for a driver who is not an expert driver, the countersteer operation can be appropriately or sufficiently guided or assisted by an appropriate amount of stabilizing force.

  Next, in the steering control device according to the present invention, the oversteer state quantity is adopted as the yawing value, and the vehicle is stabilized based on the oversteer state quantity in order to suppress oversteer. Braking force calculating means for calculating a target value of the braking force to be applied to the front wheel outside the turning of the vehicle, and braking force control means for applying a braking force to the front wheel outside the turning based on the target value of the braking force. Consider the case where it is provided.

  In this case, the stabilizing force calculating means calculates the stabilizing force to zero when the oversteer state quantity is less than or equal to a threshold value, and the threshold value of the oversteer state quantity when the oversteer state quantity is larger than the threshold value. The stabilizing force is calculated so that the stabilizing force increases from zero with an increase from the above, and the braking force calculating means is configured to calculate the braking force when the oversteer state quantity is equal to or less than the threshold value. A target value is calculated to be zero, and when the oversteer state quantity is larger than the threshold value, the braking force target value increases from zero as the oversteer state quantity increases from the threshold value. It is preferably configured to calculate a target value.

  In a vehicle in which a negative kingpin offset is adopted for the steered wheel (front wheel), if braking force is applied to the outer front wheel for turning to suppress oversteer, the vehicle yawing motion direction (so-called “torque steer”) is applied to the steering operation member ( A force (hereinafter referred to as “torque steering force”) acts on the steering wheel in the turning direction. On the other hand, as described above, the stabilizing force is applied to the steering operation member in the counter steer direction (direction in which the steered wheels are steered in the counter steer direction). Accordingly, in the process of increasing the amount of the oversteer state in the oversteer state, one of “applying the braking force to the front outer turning wheel” and “applying the stabilizing force to the steering operation member” is started before the other. Then, the driver feels the “torque steering force” resulting from “applying the braking force to the front outer wheel”, which leads to an uncomfortable feeling to the driver.

  On the other hand, in the above configuration, the start conditions (the oversteer state amount exceeds the threshold value) of “applying the braking force to the turning outer front wheel” and “applying the stabilizing force to the steering operation member” are the same. The That is, in the process of increasing the amount of oversteer state in the oversteer state, “applying the braking force to the turning outer front wheel” and “applying the stabilizing force to the steering operation member” can be started simultaneously. As a result, it becomes difficult for the driver to feel the “torque steering force” resulting from “applying the braking force to the outer front wheel”, and the stabilizing force is applied to the steering operation member without causing the driver to feel uncomfortable. Can be granted.

  As described above, when “applying the braking force to the front outer turning wheel” is executed, the stabilizing force calculating means is configured to apply the oversteer state amount to the oversteer state amount over a range where the oversteer state amount is larger than the threshold value. The stabilizing force is larger than a force (= torque steering induced force) acting in the direction of the vehicle yawing motion on the steering operation member due to the application of the braking force to the front wheel outside the turn. Further, it is preferable that the stabilizing force is calculated.

  The “torque steer-induced force” resulting from the “applying the braking force to the turning outer front wheel” described above is caused by the increase in the braking force applied as the over-steer state quantity increases. Increasing with increase. According to the above configuration, in the state where both “applying the braking force to the front outer wheel for turning” and “applying the stabilizing force to the steering operation member” are performed, the torque steering-induced force is caused by the stabilizing force. It can always be completely absorbed. Accordingly, it becomes more difficult for the driver to feel the “torque steer-causing force” resulting from “applying the braking force to the front outer wheel”.

  Embodiments of a vehicle steering control device according to the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 shows a schematic configuration of a vehicle equipped with a steering control device according to a first embodiment of the present invention.

  In the first embodiment, when the steering wheel SW (corresponding to the “steering operation member”) is operated, the rotational motion is transmitted as rotational motion to the pinion gear PN via the steering shaft SH. The rotational movement of the pinion gear PN is converted into the reciprocating movement of the rack RK (movement in the left-right direction of the vehicle body) by the rack RK that is screwed with the pinion gear PN. In response to the movement of the rack RK, the tie rod TR integrated with the rack RK moves in the left-right direction of the vehicle body, whereby the steered wheels (front wheels in this example) WHfl and WHfr are steered. Thereby, the operation angle from the neutral position of the steering wheel SW and the steering angle from the neutral position (straight-running state) of the steered wheels WHfl and WHfr are determined on a one-to-one basis.

  An electric motor Me is connected to the tie rod TR via a speed reducer Ge. The driver's steering wheel operating force (steering torque) is reduced by the driving force of the electric motor Me, and a so-called power steering control (EPS control) function is achieved.

  The brake actuator BRK has a known configuration including a plurality of solenoid valves, a hydraulic pump, an electric motor, and the like. At the time of non-control, the brake fluid pressure corresponding to the operation of the brake pedal BP by the driver is supplied to the wheel cylinder WC ** of each wheel, and the braking torque corresponding to the brake pedal operation is given to each wheel. Wheel cylinder independent of brake pedal operation during braking control such as anti-skid control (ABS control), traction control (TCS control), or vehicle stability control (ESC control) that suppresses vehicle understeer / oversteer The brake fluid pressure in the WC ** is controlled for each wheel, and the braking torque can be adjusted for each wheel. The braking torque may be adjusted using an electric brake device without using the brake fluid pressure.

  In addition, “**” added to the end of various symbols etc. “fl”, “fr” etc. added to the end of various symbols etc. to indicate which wheel the various symbols etc. relate to Is a comprehensive notation. “Fl” indicates the left front wheel, “fr” indicates the right front wheel, “rl” indicates the left rear wheel, and “rr” indicates the right rear wheel. For example, the wheel cylinder WC ** comprehensively indicates a left front wheel wheel cylinder WCfl, a right front wheel wheel cylinder WCfr, a left rear wheel wheel cylinder WCrl, and a right rear wheel wheel cylinder WCrr.

  In the first embodiment, a wheel speed sensor WS ** that detects a wheel speed Vw ** and a steering wheel rotation angle sensor SA that detects a rotation angle (from a neutral position) (steering wheel operation angle θsw) of the steering wheel SW. A steering torque sensor ST that detects the steering torque Tsw of the steering wheel SW by the driver, a yaw rate sensor YR that detects the yaw rate Yr of the vehicle body, a longitudinal acceleration sensor GX that detects the longitudinal acceleration Gx in the vehicle body longitudinal direction, A lateral acceleration sensor GY that detects a lateral acceleration Gy in the lateral direction, a steering angle sensor FS that detects a turning angle δfa from a neutral position of a front wheel (steering wheel), and a wheel cylinder that detects a wheel cylinder pressure Pw ** A pressure sensor PS ** and an electronic control unit (ECU) are provided.

  The ECU is a microcomputer composed of ECUb, ECUe, and ECUs connected to each other via a communication bus CB. The ECU is electrically connected to various actuators such as a brake actuator BRK and the various sensors.

  The ECU b is adapted to execute braking control such as ABS control, TCS control, and ESC control based on signals from the wheel speed sensor WS **, the longitudinal acceleration sensor GX, the lateral acceleration sensor GY, and the like. The ECU e performs control of an engine (not shown). The ECUs execute EPS control based on signals from the steering torque sensor ST and the like.

(Oversteer suppression control)
Next, oversteer suppression control executed by the first embodiment will be described with reference to FIG. In the first embodiment, only steering torque control is executed as oversteer suppression control. Hereinafter, this steering torque control will be described.

  In the steering torque acquisition means A1, the steering torque Tsw (operation force of the steering operation member) of the steering wheel SW by the driver is acquired by the steering torque sensor ST. The EPS torque calculation means A2 calculates a target value Teps of power steering torque (EPS torque) for reducing the driver's steering torque based on the acquired steering torque Tsw. Teps is calculated to a larger value as Tsw is larger. Teps is a value in a direction to reduce the driver's steering torque Tsw.

  The yawing value acquisition means A3 acquires a yawing value Ygc, which is a value representing the yawing motion of the vehicle. The “yawing motion” is a motion in the yaw direction of the vehicle, and is a motion that changes the direction in which the vehicle travels (a motion in which the vehicle deflects). Accordingly, the yaw rate Yr or a value calculated based on the yaw rate Yr is used as the yawing value Ygc.

  The yawing motion is generated as a result of the force acting on the wheels. Therefore, the force acting on the wheel causing the yawing motion or the yawing moment (hereinafter also simply referred to as “moment”) due to the force acting on the wheel can be adopted as the yawing value Ygc. That is, the difference (front / rear force difference) hFx between the left and right wheels of the wheel longitudinal force Fx ** (braking force for decelerating the vehicle or driving force for accelerating the vehicle) can be adopted as the yawing value Ygc.

  The longitudinal force difference hFx is acquired as shown in FIG. 3, for example. That is, first, the longitudinal force Fx ** of each wheel is acquired. The longitudinal force Fx ** of the wheel WH ** is well known by using the wheel cylinder pressure Pw ** obtained from the wheel cylinder pressure sensor PS **, the wheel speed Vw ** obtained from the wheel speed sensor WS **, etc. Can be calculated according to one of the following approaches. The longitudinal force Fx ** is, for example, the braking torque of the wheel WH ** obtained from the wheel cylinder pressure Pw **, the driving torque of the wheel WH ** obtained from the driving torque of the engine (not shown), and the differential of the wheel speed Vw **. The value can be calculated from the angular acceleration of the wheel WH ** and the rotational equation of the wheel WH **. Further, the wheel cylinder pressure sensor PS ** can be omitted. In this case, the longitudinal force Fx ** can be estimated based on the operating states of a hydraulic pump, a motor, a solenoid valve, and the like that constitute the brake actuator BRK.

Next, the left-right difference (front-rear force difference) hFx of the longitudinal force is calculated based on the longitudinal force Fx **. The longitudinal force difference hFx is, for example, hFx = (Fxfr + Fxrr) − (Fxfl + Fxrl)
Can be computed based on In the anti-skid control, so-called “select low control” may be performed in the braking torque control of the rear wheels. In this case, since a left / right difference does not occur in the rear wheel braking force, the left / right difference in the front wheel braking force can be adopted as the front / rear force difference hFx (= Fxfr−Fxfl).

  The longitudinal force calculated as described above only during the execution of the above-described μ split control (that is, slip control such as ABS control and TCS control while traveling on the μ split road surface) (described in the background section). The difference hFx may be output, and in other cases, the hFx may not be output. In this case, it is determined whether or not the μ split control is being executed (μ split determination), and based on the determination result Hmsp, if the μ split control is being executed, the longitudinal force difference hFx is output. hFx is not output.

  Further, the oversteer state quantity Jros representing the degree of oversteer of the vehicle can be adopted as the yawing value Ygc. The oversteer state quantity Jros is acquired, for example, as shown in FIG. That is, first, an actual yawing behavior YMa (for example, yaw rate Yr) is acquired. Next, a target yawing behavior (target yawing behavior) YMt is calculated. YMt is calculated based on, for example, the vehicle speed Vx obtained from the steering wheel operation angle θsw and the wheel speed Vw **. Based on the comparison result between YMa and YMt (for example, the deviation between YMa and YMt), the oversteer state quantity Jros is calculated.

  Jros can be calculated based on YMa without using YMt. In this case, Jros is calculated based on, for example, the table shown in FIG. 5, the side slip angle (slip angle) β of the vehicle, and the side slip angular velocity dβ. In the table shown in FIG. 5, with the curve corresponding to Jros = 0 as the base line, the oversteer state quantity Jros is determined to be a larger value in the upper right region.

  The side slip angle β (actual yawing behavior YMa) of the vehicle is calculated based on the yaw rate Yr, the lateral acceleration Gy, the vehicle speed Vx, and the like by a known method. Similarly, the side slip angular velocity dβ (actual yawing behavior YMa) of the vehicle is calculated based on the yaw rate Yr, the lateral acceleration Gy, the vehicle speed Vx, and the like by a known method.

  Further, in the table shown in FIG. 5, the side slip angle deviation hβ can be used for the horizontal axis instead of the side slip angle β. The side slip angle deviation hβ is a deviation between the side slip angle target value βt (target yawing behavior YMt) and the side slip angle actual value βa (actual yawing behavior YMa). Similarly, in the table shown in FIG. 5, the yaw rate deviation hYr can be used for the vertical axis instead of the side slip angular velocity dβ. The yaw rate deviation hYr is a deviation between the yaw rate target value Yrt (target yawing behavior YMt) and the actual yaw rate value Yra (actual yawing behavior YMa). Here, the side slip angle target value βt and the yaw rate target value Yrt are calculated based on the driver's driving operation (steering wheel operation angle θsw, vehicle speed Vx, etc.) by a known method. The yawing value acquisition unit A3 has been described above.

  Referring to FIG. 2 again, the counter steer value calculating means A4 calculates a counter steer value Cstr representing the degree of the driver's counter steer. As the counter steer value Ctsr, the counter steer achievement value Cts and the counter steer deficiency value Cfs are employed.

  The counter steer achievement value Cts is a value corresponding to the size of the counter steer performed (achieved) by the driver (the front wheel steering angle in the counter steer direction from the neutral position). The countersteer shortage value Cfs is a value corresponding to the countersteer size that is insufficient to stabilize the vehicle (front wheel steering angle difference).

  The counter steer achievement value Cts is the case where the sign of the yawing value Ygc (the direction of the vehicle yawing movement) and the sign of the actual steering angle δfa (the turning direction from the neutral position of the front wheels) conflict (that is, the front wheels are in the counter steer direction). Is calculated based on the magnitude of the actual steering angle δfa.

  For example, when the vehicle is turning left (that is, the yaw rate sign corresponds to the left turning direction (counterclockwise direction when viewed from above the vehicle)), and the sign of the actual steering angle δfa is the right turning direction (from the driver). In the case corresponding to the clockwise direction of the steering wheel as viewed, the actual steering angle δfa itself is adopted as the counter steer achievement value Cts. Alternatively, a yawing moment in the left turn direction due to the longitudinal force difference hFx is generated by executing the ABS control while traveling straight on the μ split road surface (the road surface with a high friction coefficient on the left side of the vehicle and the road surface with a low friction coefficient on the right side of the vehicle). In the case where the actual steering angle δfa corresponds to the right turn direction, the actual steering angle value δfa itself is adopted as the counter steer achievement value Cts.

  On the other hand, the countersteer shortage value Cfs is calculated as shown in FIG. First, based on the yawing value Ygc, a stabilizing yawing moment Mq necessary for stabilizing the vehicle is calculated. Thereby, Mq is calculated to a larger value as the yawing value Ygc is larger.

  Next, Mq is input to the inverse model of the vehicle, and the target rudder angle δft is calculated. The target rudder angle δft is a front wheel rudder angle in the counter-steer direction that is required to ensure the stability of the vehicle (that is, to generate the yawing moment Mq). The vehicle inverse model is an inverse model of a vehicle model that inputs vehicle speed, steering angle, etc. and calculates vehicle behavior such as yaw rate, and inputs vehicle behavior such as yaw rate to calculate the target steering angle δft of the front wheels. It is a model (known simultaneous equation of motion). That is, for example, with respect to the current vehicle speed Vx, lateral acceleration Gy, yaw rate Yr, and actual steering angle δfa (or steering wheel operation angle θsw), the target steering angle δft of the front wheels necessary to obtain a stable yawing moment Mq. Is calculated using an inverse model of the vehicle including a tire model representing tire characteristics.

  The actual steering angle δfa of the front wheels (steering wheels) is acquired by the actual steering angle acquisition unit A5. The actual steering angle δfa is calculated based on the detected value of the steering angle sensor FS. The actual steering angle δfa can be calculated using the relationship of δfa = θsw / SG based on the steering wheel operation angle θsw detected by the steering wheel rotation angle sensor SA. Here, SG is a steering gear ratio.

  Then, the deviation (steering angle deviation hδf = δft−δfa) between the target rudder angle δft and the actual rudder angle δfa is adopted as the countersteer shortage value Cfs.

  In the stabilization torque calculation means A6, based on the yawing value Ygc (oversteer state amount Jros or longitudinal force difference hFx) and the countersteer value Cstr (countersteer achievement value Cts or countersteer shortage value Cfs), A stabilization torque Tstb (corresponding to the “stabilization force”), which is a steering torque for guiding or assisting a counter-steer operation for stabilizing the vehicle, is calculated according to the characteristics shown in FIG. Tstb is a value in the counter steer direction (direction in which the steered wheels are steered in the counter steer direction).

  Thereby, the stabilization torque Tstb is calculated to be “0” when the yawing value Ygc (Jros, hFx) is equal to or less than the threshold value Yg1 (Jr1, hFx1), and increases when Ygc is larger than Yg1 from Yg1. Accordingly, the calculation is performed so as to increase from “0”. However, the stabilization torque Tstb is limited to a limit value Tsl or less.

  In addition, when Ygc is larger than Yg1, the stabilization torque Tstb is adjusted to a smaller value as the counter steer achievement value Cts is larger (or as the counter steer shortage value Cfs is smaller). The limit value Tsl is also adjusted to a smaller value as Cts is larger (or as Cfs is smaller).

  In the motor driving means A7, the electric motor Me is driven based on a target value Tmtr (= Teps + Tstb) for driving control of the electric motor Me obtained by adding Tstb to Teps.

  As a result, a driving force corresponding to Tmtr is applied to the tie rod TR, and the torque in the direction of reducing the steering torque Tsw of the driver (EPS torque Teps) and the torque in the counter steer direction (stabilization) with respect to the steering wheel SW. Torque Tstb). As a result, the driver is guided or assisted with the counter steer operation by this Tstb.

  As described above, the steering torque control is executed based on the steering torque Tsw, the yawing value Ygc, and the counter steer value Cstr. In the oversteer state, the stabilization torque Tstb is in the counter steer direction (vehicle yawing motion). In the opposite steering direction).

  Here, as described above, the greater the counter steer achievement value Cts (or the smaller the counter steer insufficient value Cfs), the smaller the stabilization torque Tstb (see FIG. 7). On the other hand, a large Cts (or a small Cfs) means that the driver is performing an appropriate counter-steer operation, and a small Cts (or a large Cfs) means that the driver It means that an appropriate counter steer operation is not performed (specifically, no counter steer operation is performed or the counter steer operation is insufficient).

  Therefore, when the skilled driver performs an appropriate counter-steer operation while predicting the behavior of the vehicle (large Cts or small Cfs), the stabilization torque Tstb becomes small, and the driver's steering is performed by the stabilization torque Tstb. The degree to which torque is reduced is reduced. Therefore, it is possible to suppress the “uncomfortable feeling that the steering force during the counter-steer operation is reduced unexpectedly” that the skilled driver learns.

  On the other hand, when the driver is not performing an appropriate countersteer operation (Cts small or Cfs large), the stabilization torque Tstb becomes large. As a result, for the driver who is not an expert driver, the countersteer operation can be appropriately or sufficiently guided or assisted by the large stabilization torque Tstb.

  Further, the stabilization torque Tstb may be calculated as shown in FIG. First, based on the yawing value Ygc, a reference stabilization torque (reference torque) Tsta is calculated according to the characteristics shown in FIG. The reference torque Tsta characteristic shown in FIG. 8 is a characteristic corresponding to the case where the counter steer achievement value Cts is minimum (or the counter steer shortage value Cfs is maximum) among the stabilization torque Tstb characteristics shown in FIG. This is the same as the characteristic in which Tstb is maximized. Similarly to Tstb, Tsta is a value in the counter steer direction (direction in which the steered wheels are steered in the counter steer direction).

  Next, a gain Kcs (a gain Kts corresponding to the counter steer achievement value Cts or a gain Kfs corresponding to the counter steer insufficient value Cfs) is calculated based on the counter steer value Cstr.

  The gain Kts is calculated according to the characteristics shown in FIG. As a result, the gain Kts is calculated to be “1” when Cts is equal to or less than the predetermined value Ct1 (when the driver's counter-steer operation is not performed, or even if it is performed), Cts is calculated from Ct1. Is larger than the predetermined value Ct2, it is calculated to decrease from “1” as Cts increases from Ct1, and when Cts is equal to or greater than Ct2 (the driver's counter-steer operation is performed appropriately and sufficiently) ), It is calculated as “0”.

  The gain Kfs is calculated according to the characteristics shown in FIG. Thus, the gain Kfs is calculated to be “0” when Cfs is equal to or less than the predetermined value Cf1 (when the driver's counter steering operation is performed appropriately and sufficiently), and Cfs is greater than Cf1 and is equal to the predetermined value Cf2. In the case of less than Cfs, the calculation is performed so as to increase from “0” as Cfs increases from Cf1, and when Cfs is equal to or greater than Cf2 (the driver's counter steering operation is not performed or even if performed) In this case, it is calculated as “1”.

  Then, the reference torque Tsta is multiplied by the gain Kcs (Kts or Kfs) to calculate the stabilization torque Tstb. As described above, the reference torque obtained from the reference torque characteristic with respect to the yawing value corresponding to the case where the countersteer achievement value Cts is minimum (or the countersteer shortage value Cfs is maximum) is reduced in the direction of decreasing based on the countersteer value Cstr. As a result, the stabilization torque Tstb is calculated. Also in this manner, as in the case where the stabilization torque Tstb is calculated according to the characteristics shown in FIG. 7, the stabilization torque Tstb increases as the counter steer achievement value Cts increases (or the counter steer shortage value Cfs decreases). It can be computed to a smaller value.

  Similarly, the reference torque obtained from the reference torque characteristic with respect to the yawing value corresponding to the case where the counter steer achievement value Cts is maximum (or the counter steer shortage value Cfs is minimum) is increased in the increasing direction based on the counter steer value Cstr. The correction torque Tstb may be calculated by correcting. Alternatively, the reference torque obtained from the reference torque characteristic with respect to the yawing value corresponding to the case where the counter steer value Cstr is a predetermined reference value is corrected in an increasing direction or a decreasing direction based on the counter steer value Cstr. Torque torque Tstb may be calculated.

  The operation of the first embodiment will be described below with reference to FIG. FIG. 11 shows general tire characteristics (relationship between the steering wheel slip angle α and the lateral force Fy). Here, the slip angle α of the steered wheel has a predetermined relationship with the actual rudder angle δfa (or the target rudder angle δft), and the lateral force Fy of the steered wheel is equal to the predetermined yawing moment Mq. There is a relationship. Therefore, in the tire characteristics shown in FIG. 11, the horizontal axis also represents the actual steering angle δfa (δft), and the vertical axis also represents the stabilization yawing moment Mq, so that the characteristics shown in FIG. 11 are used. The operation of the first embodiment can be described as follows. In the characteristics shown in FIG. 11, the first quadrant (upper right area) corresponds to the left turn state, and the third quadrant (lower left area) corresponds to the right turn state.

  When the vehicle is in an excessive oversteer state, it is necessary to perform a countersteer operation in order to ensure the stability of the vehicle and generate a stabilizing yawing moment Mq that stabilizes the vehicle. For example, as shown in FIG. 12, when oversteer occurs while the vehicle is turning right (turning clockwise as viewed from above the vehicle), the countersteer operation is performed in the left turn direction (steering as viewed from the driver). It is necessary to generate a stabilizing moment Mq (see FIG. 12) in the counterclockwise direction of the wheel (counterclockwise as viewed from above the vehicle).

  In this case, consider a case where the counter steer value Cstr is the counter steer achievement value Cts. In this case, the actual steering angle δfa when the front wheel is steered in the counter-steer direction (the direction opposite to the yawing movement direction, the left-turning direction in FIG. 12) as a result of the counter steering operation performed by the driver is the counter. Calculated as the steer achievement value Cts. That is, the steering angle δfa corresponding to the first quadrant in FIG. 11 is calculated as the counter steer achievement value Cts. Then, the stabilization torque Tstb determined based on the yawing value Ygc (= oversteer state quantity Jros) and the countersteer achievement value Cts is counterclockwise with respect to the steering wheel SW (counterclockwise as viewed from the driver). Direction, which is a direction in which the steered wheels are steered in the left turn direction) (see FIG. 7 and the like).

  Next, consider a case where the counter steer value Cstr is the counter steer shortage value Cfs. In this case, in order to generate the stabilization moment Mq in the left turn direction, it is necessary to perform a counter steer operation to set the front wheel steering angle to δft (corresponding to point B). However, when the front wheel steering angle is δfa (corresponding to point A) because the driver does not perform the counter steering operation or is insufficient, the steering angle deviation hδf (= δft−δfa) Is calculated as the countersteer shortage value Cfs. Then, the stabilization torque Tstb determined based on the yawing value Ygc (= oversteer state quantity Jros) and the countersteer shortage value Cfs is counterclockwise with respect to the steering wheel SW (counterclockwise as viewed from the driver). Direction, which is a direction in which the steered wheels are steered in the left turn direction) (see FIG. 7 and the like).

  Similarly, with reference to FIG. 13 corresponding to FIG. 11, consider a case where ABS control is executed on a μ split road during straight traveling. In such a case, it is necessary to perform a counter steer operation in order to suppress the deflection of the vehicle due to the left / right difference in braking force, and to generate a stabilizing yawing moment Mq that stabilizes the vehicle. For example, as shown in FIG. 14, when ABS control is activated while a vehicle is traveling straight on a road surface having a low friction coefficient on the left side of the vehicle and a high friction coefficient on the right side of the vehicle, the vehicle is deflected in the right turn direction due to the left / right difference in braking force. . At this time, in order to ensure the stability of the vehicle, the counter-steer operation is performed in the left turning direction, and the left turning direction stabilization moment Mq that cancels the yawing moment in the right turning direction caused by the left / right difference of the braking force. (See FIG. 14).

  In this case, consider a case where the counter steer value Cstr is the counter steer achievement value Cts. In this case, the actual steering angle δfa when the front wheel is steered in the countersteer direction (the direction opposite to the yawing movement direction, in the leftward turning direction in FIG. 14) as a result of the countersteering operation performed by the driver is the counter. Calculated as the steer achievement value Cts. That is, the steering angle δfa corresponding to the first quadrant in FIG. 13 is calculated as the counter steer achievement value Cts. Then, the stabilization torque Tstb determined based on the yawing value Ygc (= front-rear force difference hFx) and the countersteer achievement value Cts is the left turning direction (counterclockwise as viewed from the driver) with respect to the steering wheel SW. Direction, which is a direction in which the steered wheels are steered in the left turn direction) (see FIG. 7 and the like).

  Next, consider a case where the counter steer value Cstr is the counter steer shortage value Cfs. In this case, in order to generate the stabilization moment Mq in the left turn direction, it is necessary to perform a counter steer operation to set the front wheel steering angle to δft (corresponding to point D). However, when the front wheel steering angle is δfa (corresponding to point C) because the counter steering operation by the driver is not performed or insufficient, the steering angle deviation hδf (= δft−δfa) Is calculated as the countersteer shortage value Cfs. The stabilization torque Tstb determined based on the yawing value Ygc (= front-rear force difference hFx) and the countersteer shortage value Cfs is counterclockwise with respect to the steering wheel SW (counterclockwise as viewed from the driver). Direction, which is a direction in which the steered wheels are steered in the left turn direction) (see FIG. 7 and the like).

  As described above, according to the steering control device according to the first embodiment of the present invention, the steering torque control (“giving the stabilization torque Tstb”) is executed as the oversteer suppression control. In the steering torque control, an EPS torque Teps for reducing the steering torque is calculated based on the steering torque Tsw by the driver. Based on the yawing value Ygc (oversteer state amount Jros, longitudinal force difference hFx) corresponding to the yawing motion of the vehicle, and the countersteer value (countersteer achievement value Cts, countersteer deficiency value Cfs) indicating the degree of countersteering, A stabilizing torque Tstb for guiding or assisting the counter steer operation is calculated. Torque Teps in a direction that reduces the steering torque Tsw of the driver and torque Tstb in the counter steer direction are applied to the steering wheel SW. As a result, the driver is guided or assisted with the counter steer operation by this Tstb.

  Here, when the countersteer achievement value is small (or when the countersteer shortage value is large), that is, when the driver is not performing an appropriate countersteer operation, the stabilization torque Tstb is set to a large value. As a result, for the driver who is not an expert driver, the countersteer operation can be appropriately or sufficiently guided or assisted by the large stabilization torque Tstb. On the other hand, when the countersteer achievement value is large (or when the countersteer shortage value is small), that is, when the driver is performing an appropriate countersteer operation while predicting the behavior of the vehicle, the stabilization torque Tstb is small. Set to a value. As a result, it is possible to suppress the “uncomfortable feeling that the steering force during the counter-steer operation is reduced unexpectedly” that the skilled driver learns.

(Second Embodiment)
Next, a steering control device according to a second embodiment of the present invention will be described. In the second embodiment, the stabilization torque Tstb is adjusted based on the counter steer value Cstr, in that the stabilization torque Tstb is not applied when it is determined that the counter steer operation has been performed. Different from form. Only such differences will be described below.

  FIG. 15 is a functional block diagram when oversteer suppression control is performed by the steering control device according to the second embodiment. As shown in FIG. 15, in the second embodiment, a switching means A8 is added as compared with the first embodiment (see FIG. 2). Further, the stabilizing torque calculating means A6 calculates the stabilizing torque Tstb based only on the yawing value Ygc without using the counter steer value Cstr.

  Specifically, the stabilization torque calculating means A6 calculates the stabilization torque Tstb based on the yawing value Ygc (oversteer state quantity Jros or the longitudinal force difference hFx) according to the characteristics shown in FIG. The torque Tstb characteristic shown in FIG. 16 is the reference torque Tsta characteristic shown in FIG. 8 (that is, the countersteer achievement value Cts is the smallest among the stabilized torque Tstb characteristics shown in FIG. 7 (or the countersteer shortage). The characteristic corresponding to the case where the value Cfs is maximum) is the same as the characteristic corresponding to the case where Tstb is maximum.

  In the switching means A8, based on the counter steer value Cstr, it is determined whether or not the driver has performed a counter steer operation of the steering wheel SW. Specifically, when the counter steer achievement value Cts is larger than a predetermined value, or when the counter steer shortage value Cfs is smaller than the predetermined value, it is determined that the counter steer operation has been performed.

  When it is determined that the counter steer operation has been performed in the switching unit A8, the stabilization torque Tstb is not output to the motor drive unit A7, and when it is determined that the counter steer operation has not been performed. Then, the stabilization torque Tstb is output to the motor driving means A7.

  As described above, according to the steering control device according to the second embodiment of the present invention, it is determined that the counter steer operation has been performed when the skilled driver performs an appropriate counter steer operation while predicting the behavior of the vehicle. The stabilization torque Tstb is not applied to the steering wheel SW. Therefore, it is possible to suppress the “uncomfortable feeling that the steering force during the counter-steer operation is reduced unexpectedly” that the skilled driver learns. On the other hand, when the driver is not performing the counter steer operation, it is determined that the counter steer operation is not performed, and an appropriate amount of stabilization force can be applied. As a result, for a driver who is not an expert driver, the countersteer operation can be appropriately or sufficiently guided or assisted by an appropriate amount of stabilizing force.

(Third embodiment)
Next, a steering control device according to a third embodiment of the present invention will be described. In the third embodiment, as the oversteer suppression control, in addition to the steering torque control (“applying the stabilization torque Tstb”) in the first and second embodiments, the braking force control (“braking force to the turning outer front wheel”) is performed. Is different from the first and second embodiments. Only such differences will be described below.

  FIG. 17 is a functional block diagram when oversteer suppression control is performed by the steering control device according to the third embodiment. As shown in FIG. 17, in the third embodiment, a target braking force calculation means A9 and a braking force control means A10 are added as compared with the first embodiment (see FIG. 2). Thereby, braking force control (ESC control) for suppressing oversteer of the vehicle is performed based on Jros.

  In addition, the oversteer state quantity Jros is acquired as the yawing value Ygc. Therefore, as can be understood from FIG. 7, the application of the stabilization torque Tstb in the steering torque control is started using “Jros> Jr1” as a start condition.

  Further, as shown in FIG. 18, compared to the second embodiment (see FIG. 15), a target braking force calculation means A9 and a braking force control means A10 are added, and an oversteer state quantity is obtained as the yawing value Ygc. Jros may be acquired. Also in this case, as can be understood from FIG. 16, the application of the stabilization torque Tstb is started using “Jros> Jr1” as a start condition.

  The target braking force calculation means A9 calculates the target value (target braking force Fxt **) of the braking force of each wheel according to the characteristics shown in FIG. 19 based on the oversteer state quantity Jros. Thus, Fxt ** is calculated to be “0” when Jros is equal to or less than the threshold value Jr1, and increases from “0” as Jros increases from Jr1 when Jros is larger than Jr1 (however, , Limited to the value Fx1 or less).

  In the braking force control means A10, the brake actuator BRK is driven based on Fxt **. As a result, the braking force of each wheel is adjusted to coincide with Fxt **. As a result, the braking force of the front wheels outside the turn is increased independently of the operation of the brake pedal BP by the driver.

  As described above, the braking force control is executed based on Jros using “Jros> Jr1” as a start condition. In the third embodiment, oversteer is suppressed by this braking force control in addition to the application of Tstb in the steering torque control described above in the first and second embodiments.

  By the way, as shown in FIG. 20, consider a vehicle in which a negative kingpin offset is adopted for a steered wheel (front wheel). The negative kingpin offset refers to a case where the grounding point Pkp of the kingpin center axis is outside the front-and-rear force (Fxfr) force point Pbf in the vehicle width direction.

  In a vehicle in which a negative kingpin offset is adopted for the steering wheel, when a braking force is applied to the steering wheel, the distance (kingpin offset) Ofs between the braking force application point Pbf and the kingpin center axis grounding point Pkp Due to the presence, a torque for turning the steered wheels according to the braking force is generated. This phenomenon is also called “torque steer”.

  For example, as shown in FIG. 20, when oversteer occurs during a left turn, and when the braking force Fxfr is applied to the turning outer front wheel WHfr by the above-described braking force control (ESC control), “torque steer” Torque Tkp (= Ofs · Fxfr) for turning the front wheel in the left turn direction acts on the front wheel. This torque Tkp acts as a torque (torque steer-induced torque Tsk) that rotates the steering wheel SW in the counterclockwise direction (counterclockwise as viewed from the driver).

  On the other hand, in this case, since the countersteer direction is the right turning direction, the stabilization torque Tstb is applied to the steering wheel SW in the right turning direction (clockwise as viewed from the driver).

  Therefore, in the process of increasing the amount of oversteering in the oversteering state, when either “applying braking force to the front outer turning wheel” or “applying stabilizing torque Tstb” is started before the other (both are simultaneously If it is not started), the driver can feel the “torque steer-induced torque Tsk” resulting from “applying the braking force to the front wheel on the outside of the turn”, leading to an uncomfortable feeling to the driver.

  On the other hand, in the third embodiment, as described above, the start conditions (“Jros> Jr1”) for “applying braking force to the outer front wheel” and “applying stabilizing torque Tstb” are the same. Accordingly, in the process of increasing Jros in the oversteer state, “applying a braking force to the turning outer front wheel” and “applying the stabilizing torque Tstb” are started simultaneously. As a result, it becomes difficult for the driver to feel “torque steer-induced torque Tsk” resulting from “applying braking force to the front outer turning wheel”, and the stabilization torque Tstb is applied without causing the driver to feel uncomfortable. obtain.

  Further, due to the increase in the braking force applied with the increase of the oversteer state amount Jros, the above-mentioned “torque steer-induced torque Tsk” resulting from the “applying the braking force to the turning outer front wheel” is Increasing with increasing Jros. The characteristics indicated by the broken lines in FIGS. 7 and 16 indicate the characteristics of “torque steer caused torque Tsk” with respect to Jros. This characteristic can be obtained in advance through experiments or the like.

  Here, as can be understood from FIGS. 7 and 16, the stabilizing force Tstb against Jros is larger than the “torque steer-induced force Tsk” against Jros over a range where Jros is larger than Jr1. Accordingly, in a state where both “applying braking force to the front outer wheel for turning” and “applying stabilizing torque Tstb” are executed (when Jros> Jr1), “torque steering-induced torque Tsk” is the stabilizing force. It can always be completely absorbed by Tstb. Accordingly, it becomes more difficult for the driver to feel “torque steer-induced torque Tsk”.

  The present invention is not limited to the above embodiments, and various modifications can be adopted within the scope of the present invention. For example, in each of the above embodiments, the steering wheel SW and the steered wheels WHfl and WHfr are mechanically connected, but the steering wheel SW and the steered wheels WHfl and WHfr are not mechanically connected. A steer-by-wire system (that is, a mechanism for controlling the front wheel steering angle based on an electrical signal indicating the operation angle θsw of the steering wheel SW) may be employed. In this case, a rod-shaped member (so-called joystick) may be used as the “steering operation member” instead of the steering wheel SW.

  In addition, in each of the above embodiments, the electric motor Me is driven based on the target value Tmtr (= Teps + Tstb) for driving control of the electric motor Me, but for driving control of the electric motor Me. The electric motor Me may be driven based on the target value Tmtr (= Tstb). In this case, only Tstb is applied to the steering wheel SW in the counter steer direction. Also by this, the driver can guide or assist the counter steer operation by this Tstb.

1 is a schematic configuration diagram of a vehicle equipped with a steering control device according to a first embodiment of the present invention. FIG. 2 is a functional block diagram when oversteer suppression control is performed by the steering control device shown in FIG. 1. It is a functional block diagram at the time of acquiring the front-rear force difference between the left and right wheels as the yawing value by the yawing value acquisition means shown in FIG. FIG. 3 is a functional block diagram when an oversteer state quantity as a yawing value is acquired by the yawing value acquisition unit shown in FIG. 2. It is the graph which showed the characteristic of the amount of oversteer states to the side slip angle and side slip angular velocity of vehicles. FIG. 3 is a functional block diagram when a counter steer shortage value as a counter steer value is calculated by the counter steer value calculation means shown in FIG. 2. It is the graph which showed the table which prescribes | regulates the relationship between the yawing value and countersteer value, and the stabilization torque referred by the stabilization torque calculating means shown in FIG. FIG. 3 is a functional block diagram when a stabilization torque is calculated by the stabilization torque calculation means shown in FIG. 2. 9 is a graph showing a table that defines a relationship between a counter steer achievement value and a gain corresponding to the counter steer achievement value, which is referred to by the gain calculation unit shown in FIG. 8. FIG. 9 is a graph showing a table that defines a relationship between a counter steer deficiency value and a gain corresponding to the counter steer deficiency value, which is referred to by the gain calculation unit shown in FIG. 8. It is the graph which showed the tire characteristic (relationship between the slip angle of a steered wheel, and lateral force) at the time of turning. It is the graph which showed an example of the relation between counter steer and stabilization yawing moment at the time of turning. It is the graph which showed the tire characteristic (relationship between the slip angle of a steered wheel, and lateral force) at the time of straight ahead. It is the graph which showed an example of the relation between countersteering and stabilization yawing moment at the time of going straight. It is a functional block diagram at the time of oversteer suppression control being performed by the steering control apparatus which concerns on 2nd Embodiment of this invention. It is the graph which showed the table which prescribes | regulates the relationship between a yawing value and the stabilization torque referred by the stabilization torque calculating means shown in FIG. It is a functional block diagram at the time of oversteer suppression control being performed by the steering control apparatus which concerns on 3rd Embodiment of this invention. It is a functional block diagram at the time of oversteer suppression control being performed by the steering control apparatus which concerns on the modification of 3rd Embodiment of this invention. 19 is a graph showing a table that defines the relationship between the amount of oversteer state and the target braking force, which is referred to by the target braking force calculating means shown in FIGS. 17 and 18. It is a figure for demonstrating the "torque steer" which generate | occur | produces in the vehicle by which the negative kingpin offset is employ | adopted about the steering wheel.

Explanation of symbols

  BRK ... brake actuator, ECU ... electric control device, Me ... electric motor, SW ... steering wheel, FS ... steering angle sensor, SA ... steering wheel rotation angle sensor, ST ... steering torque sensor, YR ... yaw rate sensor, WS ** ... Wheel speed sensor

Claims (13)

Yawing value acquisition means for acquiring a yawing value that is a value corresponding to the yawing movement of the vehicle;
Based on the yawing value, to guide or assist the steering operation member operated by the driver of the vehicle to steer the steering wheel of the vehicle in the direction opposite to the direction of the vehicle yawing motion. A stabilizing force calculating means for calculating the stabilizing force of
Force applying means for applying the stabilizing force to the steering operation member in a direction opposite to the direction of the vehicle yawing motion;
In a vehicle steering control device comprising:
The stabilizing force calculation means includes:
Counter steer value calculating means for calculating a counter steer value representing the degree of steering in the direction opposite to the direction of the vehicle yawing movement of the steering wheel;
A vehicle steering control device configured to adjust the stabilizing force based on the counter steering value.   The vehicle steering control device according to claim 1,
  Operation force acquisition means for acquiring operation force of the steering operation member by the driver;
  An assist force calculating means for calculating an assist force for reducing the driver's operating force based on the operating force;
  With
  The force applying means is
  The assist force is applied to the steering operation member in a direction to reduce the operation force of the driver, and the stabilization force adjusted based on the counter steer value is applied to the steering operation member. A vehicle steering control device configured to be applied in a direction opposite to a direction of the vehicle yawing motion.   In the vehicle steering control device according to claim 1 or 2,
  The counter steer value calculation means uses, as the counter steer value, a value representing the degree of steering of the steered wheel in a direction opposite to the direction of the vehicle yawing motion with respect to the neutral position of the steered wheel. A vehicle steering control device configured as described above. The vehicle steering control device according to any one of claims 1 to 3 ,
The counter steer value calculation means includes:
As the counter steer value, a counter steer achievement value representing the degree of achievement of steering of the steered wheel in a direction opposite to the direction of the vehicle yawing motion with respect to the neutral position of the steered wheel is calculated,
The stabilizing force calculation means includes:
A vehicle steering control device configured to adjust the stabilizing force to a smaller value as the counter steer achievement value increases. The vehicle steering control device according to claim 4 ,
The counter steer value calculation means includes:
An actual rudder angle obtaining means for obtaining a value corresponding to the actual rudder angle of the steering wheel;
The counter steer achievement value is calculated based on the actual steering angle equivalent value when the steering wheel is steered in a direction opposite to the direction of the vehicle yawing motion with respect to the neutral position of the steering wheel. A vehicle steering control apparatus configured as described above. The vehicle steering control device according to any one of claims 1 to 3 ,
The counter steer value calculation means includes:
As the countersteer value, a countersteer deficiency value representing a degree of insufficient steering of the steered wheel in the direction opposite to the direction of the vehicle yawing motion with respect to the neutral position of the steered wheel is calculated,
The stabilizing force calculation means includes:
A vehicle steering control device configured to adjust the stabilizing force to a smaller value as the countersteer deficiency value is smaller. The vehicle steering control device according to claim 6 ,
The counter steer value calculation means includes:
An actual rudder angle obtaining means for obtaining a value corresponding to the actual rudder angle of the steering wheel;
Based on the yawing value, a value corresponding to a target steering angle of the steered wheel for stabilizing the vehicle in a direction opposite to the direction of the vehicle yawing motion with respect to a neutral position of the steered wheel is calculated. Target rudder angle calculation means;
With
A vehicle steering control device configured to calculate the countersteer deficiency value based on a comparison result between the target steering angle equivalent value and the actual steering angle equivalent value. Yawing value acquisition means for acquiring a yawing value that is a value corresponding to the yawing movement of the vehicle;
Based on the yawing value, to guide or assist the steering operation member operated by the driver of the vehicle to steer the steering wheel of the vehicle in the direction opposite to the direction of the vehicle yawing motion. A stabilizing force calculating means for calculating the stabilizing force of
Force applying means for applying the stabilizing force to the steering operation member in a direction opposite to the direction of the vehicle yawing motion;
In a vehicle steering control device comprising:
The stabilizing force calculation means includes:
Counter steer value calculating means for calculating a counter steer value representing the degree of steering in the direction opposite to the direction of the vehicle yawing movement of the steering wheel;
The force applying means is
Based on the counter steer value, it is determined whether or not the driver has operated the steering operation member in a direction opposite to the direction of the vehicle yawing motion, and when it is determined that the operation has been performed, A steering control device for a vehicle configured to apply the stabilization force when it is determined that the operation is not performed without applying the stabilization force.   The vehicle steering control device according to claim 8,
  Operation force acquisition means for acquiring operation force of the steering operation member by the driver;
  An assist force calculating means for calculating an assist force for reducing the driver's operating force based on the operating force;
  With
  The force applying means is
  When it is determined that the operation has been performed, the assist force is applied to the steering operation member in a direction to reduce the operation force of the driver, and the stabilization force is applied to the steering operation member. Without giving in the direction opposite to the direction of the vehicle yawing movement,
  When it is determined that the operation is not performed, the assist force is applied to the steering operation member in a direction to reduce the operation force of the driver, and the stabilization force is applied to the steering operation member. A vehicle steering control device configured to be applied in a direction opposite to the direction of the vehicle yawing motion.   In the vehicle steering control device according to claim 8 or 9,
  The counter steer value calculation means uses, as the counter steer value, a value representing the degree of steering of the steered wheel in a direction opposite to the direction of the vehicle yawing motion with respect to the neutral position of the steered wheel. A vehicle steering control device configured as described above. A vehicle steering control device according to any one of claims 1 to 10 ,
The yawing value acquisition means includes
The yawing value is configured to obtain an oversteer state quantity representing a degree of oversteer of the vehicle,
Braking force calculating means for calculating a target value of the braking force to be applied to the front wheel outside the turning of the vehicle based on the oversteer state quantity;
Braking force control means for applying a braking force to the front wheel outside the turn based on the target value of the braking force;
With
The stabilizing force calculation means includes:
When the oversteer state quantity is less than or equal to a threshold value, the stabilizing force is calculated to be zero, and when the oversteer state quantity is greater than the threshold value, the stabilization force is increased as the oversteer state quantity increases from the threshold value. Configured to calculate the stabilizing force to increase from zero,
The braking force calculation means
When the oversteer state quantity is less than or equal to the threshold, the target value of the braking force is calculated to be zero, and when the oversteer state quantity is greater than the threshold, the oversteer state quantity increases with the increase from the threshold. A vehicle steering control device configured to calculate the target value of the braking force so that the target value of power increases from zero. The vehicle steering control device according to claim 11 ,
The stabilizing force calculation means includes:
Over a range where the oversteer state quantity is greater than the threshold,
The stabilizing force for the oversteer state quantity is:
The stabilizing force is calculated so as to be larger than a force acting in the direction of the vehicle yawing motion on the steering operation member caused by applying the braking force to the front wheel outside the turn. Vehicle steering control device. A vehicle steering control device according to any one of claims 1 to 12 ,
The yawing value acquisition means includes
A vehicle steering control device configured to acquire a difference in longitudinal force between left and right wheels of the vehicle as the yawing value.

Images