JP2012121506A - Steering force control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering force control device of a vehicle capable of compensating insufficiency of self aligning torque of a steering wheel when braking force is imparted to the steering wheel by a braking control.SOLUTION: In this steering force control device, the braking force Bq[f*] imparted to the steering wheel is adjusted by the braking control based on a state of the vehicle without depending on a braking operation by a driver of the vehicle. The steering force control device includes steering force generation means TQ for imparting steering force to a steering operation member of the vehicle. The steering force imparted to the steering operation member is adjusted by the steering force generation means TQ based on a steering angle Saa and the braking force Bq[f*] imparted to the steering wheel by the braking control. The steering force is adjusted to a large value as the braking force Bq[f*] imparted to the steering wheel is larger or the steering angle Saa is larger.

Description

  The present invention relates to a vehicle steering force control apparatus that adjusts a steering force applied to a steering operation member of a vehicle by a steering force generation means to adjust a self-aligning torque of a steering wheel of the vehicle.

  In Patent Document 1, the steering force applied to the steering wheel (steering operation member) by the electric power steering device (steering force generating means) is adjusted based on the steering angle and the vehicle speed of the vehicle, and the steering wheel of the vehicle is adjusted. A steering force control device that compensates for the shortage of self-aligning torque is described. When the driver releases his hand from the steering wheel while driving the vehicle in a specific vehicle speed range (generally a low speed range) and a specific rudder angle range (generally a large rudder angle range), The purpose is to prevent the phenomenon that the rudder angle increases to the limit on the side.

JP 2003-220964 A

  By the way, when a braking force is applied to the steering wheel, the lateral force (tire lateral force) generated on the steering wheel decreases. As a result, the self-aligning torque of the steering wheel is reduced. Therefore, for example, when the braking control for applying the braking force to the steered wheels is performed without depending on the braking operation by the driver, it is necessary to compensate for the shortage of the self-aligning torque of the steered wheels. However, in the apparatus described in the above document, no consideration is given to such a viewpoint.

  The present invention has been made to address the above-described problems. An object of the present invention is to provide a steering force control device for a vehicle that can compensate for a shortage of self-aligning torque of the steered wheels when a braking force is applied to the steered wheels by the braking control.

  The vehicle steering force control apparatus according to the present invention does not depend on a braking means (MBR) for applying a braking force to the steering wheel (WH [f *]) of the vehicle and a braking operation by the driver of the vehicle. Braking control means (BRC) for adjusting a braking force (Bq [f *]) applied to the steering wheel (WH [f *]) by the braking means (MBR) based on the state of the vehicle; Is provided. The steering force control device according to the present invention includes a steering force generating means (TQ) for applying a steering force to the steering operation member (SW) of the vehicle, and a steering angle (Saa) of the steering operation member (SW). Steering angle acquisition means (SAA) for acquiring.

  The steering force control device according to the present invention is characterized in that the steering force is based on the acquired steering angle (Saa) and a calculation result (Bq [**], Fbrc) of the braking control means (BRC). A steering control means (STC) for adjusting the steering force applied to the steering operation member (SW) by the generating means (TQ) is provided. Here, it is preferable that a steering force in a direction in which the steering operation member (SW) returns to the neutral position is applied to the steering operation member (SW).

  According to this, when a braking force is applied to the steered wheel by the braking control, the steering force generating means causes the steering force (specifically, the steering operation member to return to the neutral position). Steering force) is applied. Therefore, the shortage of the self-aligning torque of the steered wheel when the braking force is applied to the steered wheel by the braking control can be compensated, and the magnitude of the self-aligning torque is an appropriate value (the braking force is applied to the steered wheel). (Value in a state where it is not given).

  In this case, the greater the braking force (Bq [f *]) applied to the steered wheel (WH [f *]), the greater the force applied to the steering operation member (SW) by the steering force generating means (TQ). It is preferable that the steering force is adjusted to a larger value. This is because the greater the braking force applied to the steered wheel, the greater the amount of decrease in the lateral force of the steered wheel resulting from the application of the braking force (and hence the amount of decrease in the self-aligning torque of the steered wheel). based on.

  In addition, it is preferable that the steering force applied to the steering operation member (SW) by the steering force generation means (TQ) is adjusted to a larger value as the acquired steering angle (Saa) is larger. . This is based on the fact that the greater the steering angle of the steered wheel, the greater the amount of decrease in the lateral force of the steered wheel resulting from the application of braking force (and hence the amount of decrease in the self-aligning torque of the steered wheel).

  In the steering force control device according to the present invention, the steering is performed based on the left-right difference (ΔBq) of the braking force (Bq [f *]) applied to the steering wheel (WH [f *]). It is preferable that the steering force applied to the steering operation member (SW) is adjusted by the force generating means (TQ).

  When there is a left-right difference in the braking force applied to the left and right steered wheels by braking control, the self-aligning torque of the steered wheels changes according to the vehicle suspension geometry (especially the kingpin offset). (Details will be described later). On the other hand, according to the above configuration, when a left-right difference is generated in the braking force of the steered wheel by the braking control, the change in the self-aligning torque due to the left-right difference in the braking force can be canceled out. Therefore, the magnitude of the self-aligning torque of the steered wheels can be maintained at an appropriate value (value in a state where no braking force is applied to the steered wheels).

1 is a schematic configuration diagram of a vehicle equipped with a vehicle steering force control apparatus according to an embodiment of the present invention. FIG. 2 is a functional block diagram when executing speed control as a first embodiment of braking control by a braking control unit of the steering force control apparatus shown in FIG. 1. It is a figure for demonstrating an effect | action and effect when the speed control as 1st Example of braking control is performed. It is a functional block diagram at the time of performing speed control as 2nd Example of braking control by the braking control means of the steering force control apparatus shown in FIG. It is a figure for demonstrating an effect | action and effect when the speed control as 2nd Example of braking control is performed. It is a functional block diagram when the steering control means of the steering force control device shown in FIG. 1 executes steering force control.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a vehicle steering force control device according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an overall configuration of a vehicle equipped with an embodiment of a vehicle steering force control device (hereinafter also referred to as “this device”) according to the present invention. This vehicle is a four-wheel drive vehicle, and includes left and right front wheels, left and right rear wheels, and differential gears (front wheel differential gear FD, rear wheel differential gear RD, and center) between front wheels and rear wheels. Differential gear CD). The present invention can also be applied to a front wheel drive vehicle or a rear wheel drive vehicle. In this apparatus, as the braking control by the braking control means BRC, speed control for maintaining the vehicle speed by suppressing acceleration due to gravity when traveling downhill (descent), that is, Hill Descent Control (Hill Descent Control) , HDC), Downhill Assist Control (DAC) is executed.

  The subscript [**] attached to the end of various symbols indicates whether the various symbols are related to any of the four wheels. "F" is the front wheel, "r" is the rear wheel, "m" is the right wheel with respect to the vehicle traveling direction, "h" is the left wheel with respect to the vehicle traveling direction, and "o" is the outer wheel with respect to the turning direction. , “I” indicates an inner wheel with respect to the turning direction. Therefore, “fh” indicates the left front wheel, “fm” indicates the right front wheel, “rh” indicates the left rear wheel, and “rm” indicates the right rear wheel. In addition, “fo” indicates a turning outer front wheel, “fi” indicates a turning inner front wheel, “ro” indicates a turning outer rear wheel, and “ri” indicates a turning inner rear wheel.

  Further, the turning direction of the vehicle may be rightward or leftward. In general, these are assigned positive and negative signs, for example, the left direction is represented by a positive sign and the right direction is represented by a negative sign. However, when the magnitude relation of values or the increase / decrease of the value is explained, the explanation becomes very complicated when the sign is taken into consideration. Therefore, in the following description, unless otherwise specified, the magnitude relationship between values and the increase / decrease in value mean the magnitude relationship between absolute values and the increase / decrease in absolute values. The predetermined value is a positive value.

(Constitution)
As shown in FIG. 1, the present device includes a steering device STR. In the steering device STR, the rotational motion of the steering wheel SW is transmitted to the small gear (pinion) PN via the steering shaft (pinion shaft). Then, the rotational motion of the pinion PN is converted into the linear motion of the rack RK by the mechanism (rack & pinion mechanism) that combines the flat gear (rack) RK and the pinion PN, and the steering wheel (front wheel) is steered.

  This apparatus includes a steering force actuator (steering force generating means) TQ. The steering force actuator TQ adjusts the steering force acting on the steering wheel SW using an electric motor (not shown) as a power source. When the steering device STR is equipped with a so-called electric power steering device (device that assists the steering operation by transmitting the driving force of the electric motor to the steering wheel), the electric motor of the electric power steering device is used as the steering force actuator TQ. obtain.

  This apparatus includes a steering torque sensor (steering force acquisition means) TS, a steering wheel angle sensor SA, and a front wheel steering angle sensor FS. A steering force (steering torque) acting on the steering wheel SW is detected by the steering torque sensor TS. The steering wheel angle sensor SA detects the rotation angle θsw from the neutral position of the steering wheel SW (corresponding to straight traveling of the vehicle).

  The steering angle δfa of the steered wheel (front wheel) is detected by the front wheel steering angle sensor FS. Specifically, as the front wheel steering angle δfa, the linear displacement δfa from the neutral position (corresponding to the straight traveling of the vehicle) of the rack RK or the rod (rack rod) RR provided with the rack RK is detected. Alternatively, as the front wheel steering angle δfa, the rotational displacement δfa from the neutral position (corresponding to the straight traveling of the vehicle) of the pinion PN or the shaft (pinion shaft) provided with the pinion PN can be detected.

  The steering wheel angle sensor SA and the front wheel steering angle sensor FS are collectively referred to as steering angle acquisition means (steering angle sensor) SAA, and the steering wheel rotation angle θsw and the front wheel steering angle δfa are collectively referred to as a steering angle. Called Saa. For example, the steering angle Saa is calculated by dividing the steering wheel rotation angle θsw detected by the steering wheel angle sensor SA by a steering gear ratio (also referred to as an overall steering gear ratio).

  This device includes a wheel speed sensor WS [**] that detects an actual wheel speed Vwa [**], a yaw rate sensor YR that detects an actual yaw rate Yra acting on the vehicle, and a longitudinal acceleration Gxa in the longitudinal direction of the vehicle body. Longitudinal acceleration sensor GX to detect, lateral acceleration sensor GY to detect lateral acceleration Gya in the lateral direction of the vehicle body, inclination angle sensor KS to detect the inclination angle Ksa of the vehicle body, and actual braking force (braking torque) (for example, wheel An actual braking force sensor (for example, a wheel cylinder pressure sensor) PW [**] for detecting a brake fluid pressure (Pwa [**] of the cylinder WC [**]) is provided.

  In addition, this apparatus includes an acceleration operation amount sensor AS that detects an operation amount Asa of a driver's acceleration operation member (for example, an accelerator pedal) AP, and an operation amount Bsa of the driver's braking operation member (for example, a brake pedal) BP. A braking operation amount sensor BS for detecting the shift, a shift position sensor HS for detecting the shift position Hsa of the speed change operation member SF, an instruction vehicle speed input means SJ for inputting an instruction vehicle speed Sj instructed by the driver, and rotation of the engine EG An engine rotation speed sensor NE that detects the speed Nea and a throttle position sensor TS that detects the opening degree Tsa of the throttle valve of the engine are provided.

  The apparatus also includes a brake actuator BRK for controlling the brake fluid pressure, a throttle actuator TH for controlling the throttle valve, a fuel injection actuator FI for controlling fuel injection, and an automatic transmission AT for controlling the shift. ing.

  In addition, the apparatus includes an electronic control unit ECU. The electronic control unit ECU is a microcomputer composed of a plurality of independent electronic control units ECU (ECUb, ECUe, ECUa, ECUs) connected to each other via a communication bus CB. The electronic control unit ECU is electrically connected to the above-described various actuators (such as BRK) and the above-described various sensors (such as WS [**]). Each system electronic control unit (ECUb, etc.) in the electronic control unit ECU executes a dedicated control program. Signals (sensor values) of various sensors and signals (internally calculated values) calculated in each electronic control unit (ECUb or the like) are shared via the communication bus CB.

  Specifically, the brake system electronic control unit ECUb performs anti-skid control (ABS control), traction control (TCS) based on signals from the wheel speed sensor WS [**], the yaw rate sensor YR, the lateral acceleration sensor GY, and the like. Control) and other slip suppression control (braking / driving force control). Further, based on the wheel speed Vwa [**] of each wheel detected by the wheel speed sensor WS [**], the vehicle speed Vxa is calculated by a known method.

  The engine system electronic control unit ECUe executes control of the throttle actuator TH and the fuel injection actuator FI based on signals from the acceleration operation amount sensor AS and the like. The transmission system electronic control unit ECUa controls the gear ratio of the automatic transmission AT. The steering system electronic control unit ECUs executes control of the steering force actuator TQ (steering force control). This steering force control will be described in detail later.

  The brake actuator BRK has a known configuration including a plurality of electromagnetic valves (hydraulic pressure regulating valves), a hydraulic pump, an electric motor, and the like. When the brake control is not executed, the brake actuator BRK supplies the brake fluid pressure corresponding to the operation of the brake operation member BP by the driver to the wheel cylinder WC [**] of each wheel, and brakes each wheel. A braking force corresponding to the operation of the operation member (brake pedal) BP is applied.

  When executing brake control such as anti-skid control (ABS control), traction control (TCS control), or vehicle stability control (ESC control) that suppresses vehicle understeer and oversteer, the brake actuator BRK controls the brake pedal BP. Independently of the operation, the brake fluid pressure in the wheel cylinder WC [**] is controlled for each wheel WH [**], and the braking force can be adjusted for each wheel.

  Each wheel is provided with a well-known wheel cylinder WC [**], brake caliper BC [**], brake pad PD [**], and brake rotor RT [**]. When brake fluid pressure is applied to the wheel cylinder WC [**] provided in the brake caliper BC [**], the brake pad PD [**] is pressed against the brake rotor RT [**], and the friction force Gives a braking force. Note that the control of the braking force is not limited to that based on the braking hydraulic pressure, and can be performed using an electric brake device.

  The throttle actuator TH has a well-known configuration including an electric motor or the like. When the throttle valve TV is closed, the output of the engine EG decreases, and when the throttle valve TV is opened, the output of the engine EG increases. To do.

(First embodiment of braking control)
Hereinafter, speed control (HDC or DAC) as a first embodiment of the braking control by the braking control means BRC of the present apparatus will be described with reference to FIG. In the first embodiment, a braking force (braking torque) is adopted as a control target.

  First, the actual vehicle speed (actual vehicle speed) Vxa is acquired in the actual vehicle speed acquisition calculation block VXA. For example, the actual vehicle speed Vxa is calculated based on the actual wheel speed Vwa [**] detected by the wheel speed sensor WS [**].

  The command vehicle speed Vxt is set in the command vehicle speed setting calculation block VXT. The command vehicle speed Vxt is set based on an operation amount (vehicle speed command amount) Sj of command vehicle speed input means (for example, a manual switch) SJ operated by the driver. Moreover, the command vehicle speed Vxt can be set based on the operation amount Asa of the acceleration operation member (for example, accelerator pedal) AP detected by the acceleration operation amount sensor AS.

  The comparison means HKX compares Vxa and Vxt, and calculates the comparison result (vehicle speed deviation) ΔVx. The vehicle speed deviation ΔVx is calculated according to the equation: ΔVx = Vxa−Vxt.

  In the reference braking force calculation block PWS, the reference braking force Pws [**] is calculated based on the deviation ΔVx. The reference braking force Pws [**] is a target value of the braking force when the vehicle is substantially straight (the steering angle Saa is less than the predetermined value sa1). The reference braking force Pws [**] is calculated to be “0” when the deviation ΔVx is less than the predetermined value vx1, and is increased from “0” as the deviation ΔVx increases when the deviation ΔVx is equal to or greater than the predetermined value vx1. Further, the reference braking force Pws [**] can be limited to the upper limit value pwm.

  In the front / rear distribution coefficient calculation block GHB, a (front / rear) distribution coefficient Ghb [**] is calculated based on a downward gradient Kdw described later. The distribution coefficient Ghb [**] is a coefficient for adjusting the front / rear braking force distribution in consideration of the downward gradient Kdw. The distribution coefficient Ghb [**] = 1 corresponds to a flat road (Kdw = 0).

  As shown by the characteristic Ckf, the front wheel allocation coefficient Ghb [f *] is “1” when the downward gradient Kdw is less than the predetermined value ke1, and increases with the downward gradient Kdw when the downward gradient Kdw is equal to or greater than the predetermined value ke1. It is calculated so as to increase from “1”. Further, the front wheel distribution coefficient Ghb [f *] can be limited to the upper limit value gh1 (> 1).

  As indicated by the characteristic Ckr, the rear wheel distribution coefficient Ghb [r *] is “1” when the downward gradient Kdw is less than the predetermined value ke1, and increases when the downward gradient Kdw is equal to or greater than the predetermined value ke1. Is calculated so as to decrease from “1”. Further, the rear wheel distribution coefficient Ghb [r *] can be limited to the lower limit value gh2 (0 ≦ gh2 <1).

  In the adjusting means CSA, the reference braking force Pws [**] is adjusted based on the distribution coefficient Ghb [**], and the reference braking force Pwr [**] in which the front / rear distribution of the braking force is adjusted is calculated. Specifically, the adjusted reference braking force Pwr [**] is calculated by multiplying the reference braking force Pws [**] by the distribution coefficient Ghb [**].

  The reference braking force Pwr [f *] of the front wheels is calculated to a relatively large value as the descending slope Kwd increases when the descending slope Kdw is equal to or greater than the predetermined value ke1. The reference braking force Pwr [r *] for the rear wheels is calculated to be a relatively small value as the descending slope Kwd increases when the descending slope Kdw is equal to or greater than the predetermined value ke1. That is, the reference braking force Pwr [**] is adjusted so that the braking force distribution on the front wheel side increases and the braking force distribution on the rear wheel side decreases as the downward gradient Kdw increases.

  In the steering angle acquisition calculation block SAA, the steering angle Saa (at least one of the steering wheel angle θsw and the front wheel steering angle δfa) is acquired.

  In the turning direction determination calculation block TRN, the turning direction Trn of the vehicle is calculated based on the steering angle Saa. Specifically, the turning direction Trn is performed based on the sign of the steering angle Saa.

  In the turning adjustment amount calculation block PDV, the adjustment amount Pvd [**] of the outer wheel on the outside of the turn and the inner wheel on the inside of the turn is calculated based on the steering angle Saa. The outer ring and the inner ring are determined based on the turning direction Trn. The adjustment amount Pvd [**] is an adjustment amount for adjusting the reference braking force Pws [**] when the vehicle turns. The adjustment amount Pvd [**] = 0 corresponds to the straight running of the vehicle.

  As indicated by the characteristic Chdi, the inner wheel adjustment amount Pvd [* i] is “0” when the steering angle Saa is less than the predetermined value sa1, and increases as the steering angle Saa increases when the steering angle Saa is equal to or greater than the predetermined value sa1. It is calculated so as to increase from “0”. Further, the adjustment amount Pvd [* i] can be limited to the upper limit value dp1. As indicated by the characteristic Chdo, the outer wheel adjustment amount Pvd [* o] is “0” when the steering angle Saa is less than the predetermined value sa1, and increases as the steering angle Saa increases when the steering angle Saa is equal to or greater than the predetermined value sa1. Calculation is performed so as to decrease from “0”. Further, the adjustment amount Pvd [* o] can be limited to the lower limit value −dp2.

  The adjustment amount Pvd [**] can be calculated based on characteristics that change stepwise. In this case, as indicated by the characteristic Cjdi, the adjustment amount Pvd [* i] of the inner ring is “0” when the steering angle Saa is less than, and is constant at the predetermined value dp1 when the steering angle Saa is equal to or greater than the predetermined value sa1. The outer wheel adjustment amount Pvd [* o] is calculated to be “0” when the steering angle Saa is less than the predetermined value −dp2 when the steering angle Saa is equal to or greater than the predetermined value sa1, as indicated by the characteristic Cjdo. Can be computed.

  The downward gradient Kdw is acquired in the downward gradient acquisition calculation block KDW. Specifically, the downward gradient Kdw is calculated based on the detection result (actual inclination angle) Ksa of the inclination angle sensor KS. Moreover, it can be calculated based on the detection result (actual longitudinal acceleration) Gxa of the longitudinal acceleration sensor GX.

  In the gradient coefficient calculation block GDW, the gradient coefficient Gdw is calculated based on the downward gradient Kdw. The gradient coefficient Gdw is a coefficient for correcting the adjustment amount Pvd [**] according to the degree of the downward gradient of the road on which the vehicle travels. As shown by the characteristic Chg, the gradient coefficient Gdw is “0” when the downward gradient Kdw is less than the predetermined value kd1, and increases as the downward gradient Kdw increases when the downward gradient Kdw is equal to or greater than the predetermined value kd1 and less than the predetermined value kd2. On the other hand, when the downward gradient Kdw is equal to or greater than the predetermined value kd2, it is calculated as “1”. Further, as indicated by the characteristic Cjg, Gdw = 0 can be calculated when the downward gradient Kdw is less than the predetermined value kd1, and Gdw = 1 can be calculated when the downward gradient Kdw is equal to or greater than the predetermined value kd1.

  In the adjustment means CSX, the adjustment amount Pvd [**] is corrected by the gradient coefficient Gdw. Specifically, the corrected adjustment amount Pwd [**] is calculated by multiplying the adjustment amount Pvd [**] by the gradient coefficient Gdw. Thus, as the downward gradient Kdw is larger, the adjustment amount Pvd [* i] is corrected to a relatively large value, and the adjustment amount Pvd [* o] is adjusted to a relatively small value. On the other hand, as the downward gradient Kdw is smaller, the adjustment amount Pvd [* i] is corrected to a relatively small value, and the adjustment amount Pvd [* o] is adjusted to a relatively large value.

  In the adjusting means CSY, the reference braking force Pwr [**] after the front / rear distribution adjustment is adjusted by Pwd [**]. Specifically, the adjustment amount Pvd [**] is added to the reference braking force (the target value of the braking force for achieving the indicated vehicle speed) Pwr [**], and the final target braking force Pwt [** ] Is calculated.

  Thereby, when the downward gradient Kdw is equal to or greater than the predetermined value kd1 and the steering angle Saa is equal to or greater than the predetermined value sa1, the target braking force Pwt [* i] of the inner wheel is determined to be equal to or greater than the reference braking force Pwr [* i]. The target braking force Pwt [* o] of the outer ring is determined to be equal to or less than the reference braking force Pwr [* o]. In addition, the difference between the target braking force Pwt [* i] and the target braking force Pwt [* o] increases as the steering angle Saa increases and the descending slope Kdw increases. On the other hand, the smaller the steering angle Saa and the smaller the downward gradient Kdw, the smaller the difference between the target braking force Pwt [* i] and the target braking force Pwt [* o].

  Based on the target braking force Pwt [**], the drive motor DRV drives the electric motor / hydraulic pump and solenoid valve of the brake actuator BRK to adjust the braking hydraulic pressure of the wheel cylinder WC [**]. Is done. Based on the actual braking force Pwa [**] detected by the actual braking force sensor PW [**], the servo control is performed so that the actual braking force Pwa [**] matches the target braking force Pwt [**]. Executed. As described above, in the first embodiment of the braking control, the braking force (braking torque) is adopted as the control target, and the speed control (HDC or DAC) is achieved.

(Operation and effect of speed control as first embodiment of braking control)
Next, the operation and effect of speed control (HDC or DAC) as a first embodiment of braking control will be described with reference to FIG. FIG. 3 shows an example in which the vehicle turns leftward on a downhill road with a downward slope Kdw of a predetermined value kd1 or more and the steering angle Saa is a predetermined value sa1 or more.

  In this case, the braking force of the turning outer wheel (at least one of the right front wheel and the right rear wheel in the case of left turning) WH [* o] is reduced from the reference braking force. As a result, the braking force Fx [* o] of the outer wheel is reduced. Due to the decrease in the outer wheel braking force, a braking force difference is generated between the inner and outer wheels, and a yaw moment YM is generated in the vehicle. As a result, the turning performance (turning ability and steering followability) of the vehicle is improved.

  Further, the braking force of the turning inner wheel (at least one of the left front wheel and the left rear wheel in the case of left turning) WH [* i] is increased from the reference braking force. As a result, the braking force Fx [* i] of the inner wheel is increased. Due to the increase in the inner ring braking force, a braking force difference is generated between the inner and outer wheels, and a yaw moment YM is generated in the vehicle. As a result, the turning performance (turning ability and steering followability) of the vehicle is improved.

  Only one of the decrease in the outer ring braking force and the increase in the inner ring braking force may be performed, but it is preferable that both be performed simultaneously as in the first embodiment. As a result, the occurrence of changes in the longitudinal force (braking force) in the entire vehicle is suppressed, and the vehicle speed is instructed by the driver (the vehicle speed instruction amount Sj or the indicated vehicle speed set according to the acceleration operation amount Asa). Can be easily maintained.

  The adjustment of the braking force from the reference braking force during downhill and turning as described above may be performed on both the front wheel side and the rear wheel side, but is not performed on the rear wheel side, but only on the front wheel side that is the steering wheel. Preferably, it is done. In this case, a yaw moment is generated due to a braking force difference between the inner and outer wheels on the front wheel side.

  During downhill, skidding is likely to occur on the rear wheel where the ground contact load is reduced. Therefore, when the lateral force fluctuation of the rear wheel occurs, the lateral slip of the rear wheel is induced due to the lateral force fluctuation, and the stability of the vehicle is likely to be lowered. Under such circumstances, since the braking force is not adjusted on the rear wheel side, the change in the braking force on the rear wheel side is suppressed, and the lateral force fluctuation of the rear wheel can be suppressed. As a result, the stability of the vehicle can be ensured.

  On the other hand, a braking force difference between the inner and outer wheels is given on the front wheel side. Therefore, the lateral force of the outer front wheel having a small braking force is large and the lateral force of the inner front wheel having a large braking force is small compared to the case where the difference in braking force between the inner and outer wheels is not applied. On the other hand, in general, the steering reaction force felt by the driver correlates with the larger one of the lateral forces of the left and right front wheels which are steering wheels. Accordingly, the steering reaction force is increased as compared with the case where the difference in braking force between the inner and outer wheels is not applied. As a result, the driver can easily grasp the neutral position of the steering, and the steering feeling can be improved.

  In the first embodiment, the braking force adjustment amount (absolute value) Pvd [**] increases as the downhill gradient Kdw increases, and the braking force difference between the inner and outer wheels increases. The greater the down slope (the steeper downhill), the smaller the rear wheel ground contact load and the more the front wheel ground load. Therefore, when the braking load on the rear wheel is increased, the rear wheel is likely to be locked. For this reason, in order to keep the vehicle speed constant, it is necessary to increase the braking load on the front wheels. That is, the braking force of the rear wheels needs to be reduced and the braking force of the front wheels needs to be increased.

  Here, when the braking load on the front wheels is increased, the maximum value of the lateral force that can be generated on the front wheels decreases. Due to this, the steering followability is lowered (the vehicle is difficult to bend). Under such circumstances, the greater the downhill gradient Kdw, the greater the difference in braking force between the inner and outer wheels, thereby ensuring the turning performance of the vehicle.

As described above, the braking control means BRC according to the first embodiment is
"Indicated vehicle speed acquisition means for acquiring an instruction vehicle speed that is a vehicle speed instructed by a driver of the vehicle when the vehicle travels downhill;
Actual vehicle speed acquisition means for acquiring the actual vehicle speed of the vehicle;
Braking means for applying a braking force to each wheel of the vehicle;
Steering angle acquisition means for acquiring the steering angle of the vehicle;
Downhill acquisition means for acquiring the downhill gradient;
With
In order to bring the actual vehicle speed closer to the commanded vehicle speed, when the slope of the downhill is equal to or greater than a predetermined value and the steering angle is equal to or greater than a predetermined value, an inner wheel braking force, which is a braking force of a turning inner wheel of the vehicle, is The braking force of each wheel applied by the braking means is controlled so as to be larger than the outer wheel braking force that is the braking force of the turning outer wheel of the vehicle. "
Can be described.

Furthermore, the braking control means BRC according to the first embodiment is
“Comprising a reference braking force calculating means for calculating a reference braking force of each wheel based on a comparison result between the actual vehicle speed and the indicated vehicle speed,
The braking force of each wheel is controlled so that the outer wheel braking force is smaller than the reference braking force of the corresponding wheel and the inner wheel braking force is larger than the reference braking force of the corresponding wheel. "
Can be described.

(Second embodiment of braking control)
Next, speed control (HDC or DAC) as a second embodiment of the braking control by the “braking control means” of the present apparatus will be described with reference to FIG. The second embodiment is different from the first embodiment in which a braking force (braking torque) is adopted as a control object in that the wheel speed is adopted as a control object. Hereinafter, differences between FIG. 2 and FIG. 4 will be described.

  The front / rear coefficient calculation block GFR calculates the front / rear coefficient Gfr [**] based on the downward gradient Kdw. The front-rear coefficient Gfr [**] is a coefficient for converting the indicated vehicle speed Vxt into the target wheel speed Vws [**] of each wheel in consideration of the downward gradient Kdw. The front-rear coefficient Gfr [**] = 1 corresponds to a flat road (Kdw = 0).

  As shown by the characteristic Clf, the front wheel front-rear coefficient Gfr [f *] is “1” when the downward gradient Kdw is less than the predetermined value kf1, and increases with the downward gradient Kdw when the downward gradient Kdw is equal to or greater than the predetermined value kf1. Calculation is performed so as to decrease from “1”. Further, the front wheel front-rear coefficient Gfr [f *] can be limited to the lower limit value gf2 (0 ≦ gf2 <1).

  As shown by the characteristic Clr, the front-rear coefficient Gfr [r *] of the rear wheel is “1” when the downward gradient Kdw is less than the predetermined value kf1, and is increased when the downward gradient Kdw is equal to or greater than the predetermined value kf1. Is calculated so as to increase from “1”. Further, the rear wheel front-rear coefficient Gfr [r *] can be limited to the upper limit value gh1 (> 1).

  In the adjustment means CSB, the indicated vehicle speed Vxt is adjusted based on the front-rear coefficient Gfr [**], and the target wheel speed Vws [**] of each wheel is calculated. Specifically, the target wheel speed Vws [**] is calculated by multiplying the indicated vehicle speed Vxt by the longitudinal coefficient Gfr [**].

  The target wheel speed Vws [**] of the front wheels is calculated to a relatively small value as the downward gradient Kwd is larger when the downward gradient Kdw is equal to or greater than the predetermined value kf1. The target wheel speed Vws [**] of the rear wheel is calculated to a relatively large value as the downward gradient Kwd is larger when the downward gradient Kdw is equal to or greater than the predetermined value kf1. An increase in target wheel speed causes a decrease in wheel braking force, and a decrease in target wheel speed causes an increase in wheel braking force. That is, with the target wheel speed Vws [**] adjusted between the front and rear wheels, the braking force distribution increases so that the braking force distribution on the front wheel side increases and the braking force distribution on the rear wheel side decreases as the descending gradient Kdw increases. Is adjusted.

  In the turning adjustment amount calculation block GVW, the adjustment amount Gvw [**] is calculated based on the steering angle Saa. The adjustment amount Gvw [**] is an adjustment for converting the target wheel speed Vws [**] adjusted between the front and rear wheels into the target wheel speed Vwt [**] of each wheel in consideration of the steering angle Saa. Amount. The adjustment amount Gvw [**] = 0 corresponds to the straight running of the vehicle.

  As indicated by the characteristic Chvi, the inner wheel adjustment amount Gvw [* i] is “0” when the steering angle Saa is less than the predetermined value sa1, and increases as the steering angle Saa increases when the steering angle Saa is equal to or greater than the predetermined value sa1. Calculation is performed so as to decrease from “0”. Further, the adjustment amount Gvw [* i] can be limited to the lower limit value −gv2. As shown by the characteristic Chvo, the outer wheel adjustment amount Gvw [* o] is “0” when the steering angle Saa is less than the predetermined value sa1, and increases as the steering angle Saa increases when the steering angle Saa is equal to or greater than the predetermined value sa1. It is calculated so as to increase from “0”. Further, the adjustment amount Gvw [* o] can be limited to the upper limit value gv1.

  The adjustment amount Gvw [**] can be calculated based on characteristics that change stepwise. In this case, as indicated by the characteristic Cjvi, the inner wheel adjustment amount Gvw [* i] is “0” when the steering angle Saa is less than the predetermined value sa1, and is the predetermined value − when the steering angle Saa is equal to or greater than the predetermined value sa1. As shown by the characteristic Cjvo, the outer wheel adjustment amount Gvw [* o] is “0” when the steering angle Saa is less than the predetermined value sa1, and the steering angle Saa is equal to or greater than the predetermined value sa1. Then, it can be calculated with a predetermined value gv1.

  In the adjusting means CSZ, the final target wheel speed Vwt [**] of each wheel is the target wheel speed Vws [**] adjusted between the front and rear wheels by the adjustment amount Gvw [**] and the gradient coefficient Gdw. Calculated by correcting. Specifically, the target wheel speed Vwt [**] is calculated according to the equation Vwt [**] = Vws [**] + Gdw · Gvw [**].

  Thus, when the downward gradient Kdw is equal to or greater than the predetermined value kd1 and the steering angle Saa is equal to or greater than the predetermined value sa1, the target wheel speed Vwt [* i] of the inner wheel is adjusted to the target wheel speed Vws [* adjusted between the front and rear wheels. i] is determined as follows, and the target wheel speed Vwt [* o] of the outer ring is determined to be equal to or higher than the target wheel speed Vws [* o]. In addition, the difference between the target wheel speed Vwt [* o] and the target wheel speed Vwt [* i] increases as the steering angle Saa increases and the descending gradient Kdw increases. On the other hand, the smaller the steering angle Saa and the smaller the downward gradient Kdw, the smaller the difference between the target wheel speed Vwt [* o] and the target wheel speed Vwt [* i].

  The comparison means HKY compares the actual wheel speed Vwa [**] with the target wheel speed Vwt [**] and calculates the comparison result ΔVw [**]. The comparison result (wheel speed deviation) ΔVw [**] is calculated according to the equation: ΔVw [**] = Vwa [**] − Vwt [**].

  In the target braking force calculation block PWT, the target braking force Pwt [**] is calculated based on the deviation ΔVw [**]. The target braking force Pwt [**] is set to “0” when the deviation ΔVw [**] is less than the predetermined value vw1, and the deviation ΔVw [**] is equal to or larger than the predetermined value vw1. It is calculated so as to increase from “0” as the deviation ΔVw [**] increases. Further, the target braking force Pwt [**] can be limited to the upper limit value pwn.

  This target braking force Pwt [**] is provided to the drive means DRV, and servo control is executed so that the actual braking force Pwa [**] matches the target braking force Pwt [**]. As described above, in the second embodiment of the braking control, the wheel speed is adopted as the control target, and the speed control (HDC or DAC) is achieved.

(Operation / effect of speed control as second embodiment of braking control)
Next, the operation and effect of speed control (HDC or DAC) as a second embodiment of braking control will be described with reference to FIG. FIG. 5 shows an example of a case where the vehicle turns leftward on a downhill road having a downward slope Kdw of a predetermined value kd1 or more and the steering angle Saa is a predetermined value sa1 or more, as in FIG. ing.

  In this case, the target wheel speed Vwt [* o] of the turning outer wheel (at least one of the right front wheel and the right rear wheel in the case of left turning) WH [* o] is increased from the target wheel speed Vws [* o]. Is done. As a result, a difference occurs in the target wheel speed Vwt [**] between the inner and outer wheels, and this difference generates a yaw rate. As a result, the turning performance (turning ability and steering followability) of the vehicle is improved. At this time, an increase in the target wheel speed Vwt [* o] of the outer ring results in a decrease in the braking force of the outer ring.

  Further, the target wheel speed Vwt [* i] of the turning inner wheel (at least one of the left front wheel and the left rear wheel in the case of left turning) WH [* i] is reduced from the target wheel speed Vws [* i]. The As a result, a difference occurs in the target wheel speed Vwt [**] between the inner and outer wheels, and this difference generates a yaw rate. As a result, the turning performance (turning ability and steering followability) of the vehicle is improved. At this time, as a result of the decrease in the target wheel speed Vwt [* o] of the inner ring, the braking force of the inner ring is increased.

  Only one of the increase in the outer ring target wheel speed and the decrease in the inner ring target wheel speed may be performed, but it is preferable that both are performed simultaneously as in the second embodiment. As a result, the outer ring braking force is reduced and the inner ring braking force is increased. Therefore, the occurrence of a change in the longitudinal force (braking force) in the entire vehicle is suppressed, and the vehicle speed is set to the vehicle speed (vehicle speed command amount Sj or command vehicle speed set according to the acceleration operation amount Asa) instructed by the driver. It can be easily maintained.

  The adjustment of the target wheel speed during downhill and turning as described above may be performed on both the front wheel side and the rear wheel side, but may not be performed on the rear wheel side, but only on the front wheel side that is the steering wheel. preferable. Adjustment of the target wheel speed results in a change in the braking force. Therefore, as in the first embodiment, the lateral force fluctuation of the rear wheels can be suppressed, and the stability of the vehicle can be ensured. Furthermore, the steering reaction force increases, and the steering feeling can be improved.

  In the second embodiment, the larger the downhill gradient Kdw, the larger the target wheel speed difference between the inner and outer wheels. That is, the greater the downhill gradient Kdw, the greater the braking force difference between the inner and outer wheels. Therefore, as in the first embodiment, the turning performance of the vehicle can be reliably ensured.

As described above, the braking control means BRC according to the second embodiment is as follows.
"Indicated vehicle speed acquisition means for acquiring an instruction vehicle speed that is a vehicle speed instructed by a driver of the vehicle when the vehicle travels downhill;
Determining means for determining a target wheel speed of each wheel of the vehicle based on the indicated vehicle speed;
Real wheel speed acquisition means for acquiring the actual wheel speed of each wheel;
Braking means for applying a braking force to each wheel;
Steering angle acquisition means for acquiring the steering angle of the vehicle;
Downhill acquisition means for acquiring the downhill gradient;
With
In order to bring the actual wheel speed closer to the target wheel speed, the braking force of each wheel applied by the braking means is controlled,
The determining means includes
When the slope of the downhill is a predetermined value or more and the steering angle is a predetermined value or more, the inner wheel target speed that is the target wheel speed of the turning inner wheel of the vehicle is the target wheel speed of the turning outer wheel of the vehicle. The target wheel speed of each wheel is determined so as to be smaller than the outer ring target speed. "
Can be described.

Furthermore, the braking control means BRC according to the second embodiment is
“The decision means
Reference target wheel speed calculating means for calculating a reference target wheel speed of each wheel based on the indicated vehicle speed,
The target wheel speed of each wheel is determined so that the outer wheel target speed is larger than the reference target wheel speed of the corresponding wheel and the inner ring target speed is smaller than the reference target wheel speed of the corresponding wheel. "
Can be described.

(Steering force control by this device)
Hereinafter, the steering force control by the steering control means STC of the present apparatus will be described with reference to FIG.

  When a braking force is applied to the steered wheel, the lateral force (tire lateral force) generated on the steered wheel is reduced, and the self-aligning torque of the steered wheel is reduced (insufficient). The purpose of the steering force control by this device is that the above-described “self-control of the steering wheel WH [f *] is applied when the braking force is applied to the steering wheel WH [f *] by the braking control by the braking control means BRC. This is to compensate for the lack of lining torque. As the braking control by the braking control means BRC, for example, speed control as the first and second embodiments of the braking control described above can be assumed.

  First, the compensation steering force (compensation steering torque) Sat is calculated based on the steering angle Saa and the wheel braking force Bq [**] in the compensation steering force calculation block SAT. The wheel braking force Bq [**] is determined by the target braking force Pwt [**] and actual braking force Pwa [*] of the braking control (first and second embodiments) in the braking force calculation block BQE of the braking control means BRC. *] And at least one of the operating states of the electromagnetic valve in the brake actuator BRK.

  The compensation steering force Sat is a target value of the steering force (steering torque) to be applied to the steering wheel SW in order to compensate for the “insufficiency of the self-aligning torque of the steered wheels” caused by the application of the braking force. is there. The compensation steering force Sat is set to the steering force in the direction in which the steering wheel SW returns to the neutral position (that is, the direction in which the self-aligning torque increases or the direction in which the lack of self-aligning torque is compensated).

  The compensation steering force Sat is a braking index calculated based on the braking force (braking torque) Bq [**] of the wheel (an index indicating the magnitude of the braking force Bq [f *] applied to the steered wheel) Bqidx. It is calculated so as to increase with the increase of. This is because, as the braking force Bq [f *] applied to the steered wheel is larger, the lateral force of the steered wheel is reduced due to the application of the braking force (therefore, the self-aligning torque of the steered wheel is decreased). Based on the large amount). As a braking index Bqidx, based on the wheel braking force Bq [**], the larger one of the average value Bqav of Bq [f *], the sum Bqsf of Bq [f *], or Bq [f *] A value of Bqmx can be used. Further, the braking index Bqidx can be calculated based on at least one of Bqav, Bqsm, and Bqmx.

  Furthermore, the compensation steering force Sat is calculated so as to increase as the steering angle Saa increases. This is based on the fact that the greater the steering angle of the steered wheel, the greater the amount of decrease in the lateral force of the steered wheel resulting from the application of braking force (and hence the amount of decrease in the self-aligning torque of the steered wheel).

  In the compensation steering force calculation block SAT, the compensation steering force Sat is calculated based on the braking index Bqidx that represents the magnitude of the braking force Bq [f *] applied to the steered wheels. The compensation steering force Sat [f *] is calculated for the direction wheel WH [f *], and the final compensation steering force Sat can be calculated. As described above, the compensation steering force Sat [f *] of each steered wheel is calculated so as to increase as the braking force Bq [f *] increases and to increase as the steering angle Saa increases. Then, the auxiliary steering force Sat includes the compensation steering force Sat [fm] obtained based on one braking force (for example, Bq [fm]) of the steered wheel and the steering angle Saa, and the other control force of the steered wheel. It can be calculated based on the compensation steering force Sat [fh] obtained based on the power (for example, Bq [fh]) and the steering angle Saa (for example, on the average value thereof).

  Further, in the compensation steering force calculation block SAT, instead of the wheel braking force Bq [**], a signal indicating whether or not the braking control by the braking control means BRC is being executed (execution flag Fbrc of the braking control means BRC). Thus, the compensation steering force Sat can be calculated. Specifically, when the execution flag Fbrc indicates execution of braking control (for example, Fbrc = 1), the compensation steering force Sat is compared with when Fbrc indicates non-execution of braking control (for example, Fbrc = 0). Is calculated to a large value. For example, when Fbrc represents non-execution of braking control, the compensation steering force Sat is calculated as “0 (no steering force compensation is performed)”, and when Fbrc represents execution of braking control, the compensation steering force Sat is set in advance. The calculated value is calculated to compensate for the steering force.

  In the current control calculation block IST, a current value (current instruction value) Ist supplied to the electric motor driving means DRW of the steering force generating means (steering force actuator) TQ is calculated based on the compensation steering force Sat. In the electric motor driving means DRW, the current supplied to the electric motor based on the current instruction value Ist is controlled.

  Thereby, a steering force (steering torque) having the same magnitude and direction as the compensation steering force Sat is applied to the steering wheel SW. As a result, the “insufficiency of the steering wheel self-aligning torque” caused by the application of the braking force can be compensated based on the steering force corresponding to the compensation steering force (target value) Sat. Therefore, the magnitude of the self-aligning torque of the steered wheels can be maintained at an appropriate value (value in a state where no braking force is applied to the steered wheels).

  In addition, if there is a left-right difference in the braking force applied to the left and right steered wheels, the self-aligning torque of the steered wheels changes according to the vehicle suspension geometry (especially the kingpin offset). Can do. This point will be described below.

  The kingpin (the center axis of rotation where the steered wheel is steered when the steering wheel is operated) is the offset (also called the scrub radius) when the kingpin centerline intersects the road surface when the car is viewed from the front. To the ground contact center of the tire. When the distance is zero, it is called center point steering (zero scrub), and when the kingpin center line is inside the tire ground center, it is called positive offset (positive scrub), and the kingpin center line is tire ground center. What is on the outer side is called a negative offset (negative scrub).

  In particular, in a four-wheel drive vehicle (so-called SUV) for off-road driving, it is necessary to ensure a sufficient suspension stroke, and therefore the kingpin offset (scrub radius) of the steered wheel tends to be set positive. strong.

  When a kingpin offset is set on the steered wheel (other than zero scrub), if there is a left / right difference in the braking force between the left and right steered wheels, the left / right braking force will cause the braking force Steering force is generated in the steering direction generated by the larger side.

  Generally, when the left and right steering wheels have a left-right difference when the kingpin offset of the steered wheels is set to positive, the left and right sides of the steered wheels have the greater braking force. The steering force is generated in the same steering direction as the vehicle turning direction (yawing direction). Therefore, for example, when the first and second embodiments described above are executed as braking control and the vehicle is turning (inner wheel braking force> outer wheel braking force), the steering neutral position (vehicle) Steering force is generated in a direction away from the vehicle (that is, a steering direction that increases turning and a direction in which self-aligning torque decreases).

  On the other hand, when the left and right steering wheel braking force has a left / right difference when the steering wheel kingpin offset is set to negative, the left and right side of the steering wheel has the larger braking force. Steering force is generated in a steering direction that is the direction in which the vehicle is turned and is opposite to the turning direction of the vehicle (the yawing direction). Therefore, for example, when the first and second embodiments described above are executed as the braking control and the vehicle is turning (inner wheel braking force> outer wheel braking force), the steering wheel approaches the neutral position of steering. A steering force is generated in the direction (that is, the steering direction that reduces the turn and the direction in which the self-aligning torque increases).

  In other words, when there is a left-right difference in the braking force of the left and right steering wheels, the self-aligning torque of the steering wheels can change according to the geometry of the vehicle suspension. Another object of the steering force control by this device is that the “steering wheel” described above in the case where there is a left-right difference in the braking force applied to the steering wheel WH [f *] by the braking control by the braking control means BRC. This is to cancel the “change in the self-aligning torque of WH [f *]”. As the braking control by the braking control means BRC, for example, speed control as the first and second embodiments of the braking control described above can be assumed.

  In the adjustment steering force calculation block STQ, the adjustment steering force Stq is calculated based on the braking force left / right difference ΔBq of the steered wheel WH [f *]. The braking force left / right difference ΔBq is calculated in the braking force left / right difference calculation block DBQ of the braking control means BRC based on the calculation result (Bq [**]) of the braking force calculation block BQE described above. The adjustment steering force Stq is a target value of the steering force (steering torque) to be applied to the steering wheel SW in order to cancel the “change in the self-aligning torque of the steered wheels” caused by the above-described difference in the braking force left and right. .

  When the offset of the king pin of the steered wheel is set to be positive, the adjustment steering force Stq is “the steering direction generated by the side with the larger braking force among the left and right and the steering direction opposite to the turning direction of the vehicle”. Set to steering force. Therefore, for example, when the first and second embodiments described above are executed as braking control and the vehicle is turning (inner wheel braking force> outer wheel braking force), the adjustment steering force Stq is set so that the steering wheel SW is in the neutral position. The steering force is set in the returning direction (that is, the direction in which the self-aligning torque increases and the direction in which the decrease in the self-aligning torque is canceled).

  Similarly, when the offset of the king pin of the steered wheel is set to a negative value, the adjusted steering force Stq is “the steering direction generated by the side with the larger braking force among the left and right and the same steering direction as the turning direction of the vehicle” Is set to the steering force. Therefore, for example, when the first and second embodiments described above are executed as the braking control and the vehicle is turning (inner wheel braking force> outer wheel braking force), the adjustment steering force Stq is obtained from the neutral position of the steering wheel SW. The steering force is set in the direction of leaving (that is, the direction in which the self-aligning torque decreases, the direction in which the increase in self-aligning torque is canceled).

  The adjustment steering force Stq is calculated so as to increase as the braking force left / right difference ΔBq increases. This is based on the fact that the larger the braking force left / right difference ΔBq of the steered wheel, the greater the amount of change in the self-aligning torque of the steered wheel due to the braking force left / right difference.

  The adjusted steering force (target value) Stq is added to the compensation steering force (target value) Sat, and the final target steering force (target value) Stu is calculated. Thereby, the compensation steering force Sat is adjusted by the adjustment steering force Stq.

  In the current control calculation block IST, the current value (current instruction value) Ist supplied to the electric motor driving means DRW of the steering force generating means (steering force actuator) TQ is changed to the target steering force Stu adjusted by the adjusted steering force Stq. Calculated based on In the electric motor driving means DRW, the current supplied to the electric motor M based on the current instruction value Ist is controlled.

  As a result, a steering force (steering torque) having a magnitude and direction equal to the target steering force Stu adjusted by the adjusted steering force Stq is applied to the steering wheel SW. As a result, the “shortage of steering wheel self-aligning torque” resulting from the application of the braking force described above can be compensated based on the steering force corresponding to the compensation steering force (target value) Sat, and the adjustment steering Based on the steering force corresponding to the force (target value) Stq, the “change in the self-aligning torque of the steered wheels” caused by the braking force left-right difference described above can be canceled out.

  WS [**] ... Wheel speed sensor, SA ... Steering wheel angle sensor, FS ... Front wheel steering angle sensor, KS ... Inclination angle sensor, PW ... Wheel cylinder pressure sensor, SJ ... Instruction vehicle speed input means, BRK ... Brake actuator, TQ ... Steering force actuator

Claims (6)

Braking means for applying braking force to the steering wheel of the vehicle;
Braking control means for adjusting the braking force applied to the steering wheel by the braking means based on the state of the vehicle without depending on the braking operation by the driver of the vehicle;
Steering force generating means for applying a steering force to the steering operation member of the vehicle;
Steering angle acquisition means for acquiring a steering angle of the steering operation member;
Steering control means for adjusting a steering force applied to the steering operation member by the steering force generating means based on the acquired steering angle and a calculation result of the braking control means;
A vehicle steering force control device. The vehicle steering force control apparatus according to claim 1,
The steering control means includes
The vehicle steering force control apparatus configured to adjust the steering force applied to the steering operation member by the steering force generation means to a larger value as the braking force applied to the steering wheel is larger. In the vehicle steering force control device according to claim 1 or 2,
The steering control means includes
A vehicle steering force control apparatus configured to adjust a steering force applied to the steering operation member by the steering force generation unit to a larger value as the acquired steering angle is larger. In the vehicle steering force control device according to any one of claims 1 to 3,
The steering control means includes
A steering force control apparatus for a vehicle configured to apply a steering force in a direction in which the steering operation member returns to a neutral position to the steering operation member. In the vehicle steering force control device according to any one of claims 1 to 4,
The steering control means includes
A target steering force is determined based on the acquired steering angle and a calculation result of the braking control unit, and a steering force applied to the steering operation member by the steering force generation unit based on the target steering force. A steering force control device for a vehicle configured to adjust the vehicle. The vehicle steering force control apparatus according to any one of claims 1 to 5,
The steering control means includes
A steering force control device for a vehicle configured to adjust a steering force applied to the steering operation member by the steering force generation means based on a left-right difference in braking force applied to the steering wheel.

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