VEHICLE CONTROL DEVICE, VEHICLE CONTROL METHOD, AND VEHICLE CONTROL SYSTEM

Abstract

The vehicle control device is provided in a vehicle that has a steer-by-wire system for steering the right and left steered road wheels, which are mechanically independent of the steering wheel and whose steering roll radius is set to negative. When a control unit contained in the vehicle control device detects an abnormal steering signal in the steer-by-wire system, the control unit issues a drive and brake command between the right and left steered road wheels based on a steering input at the steering wheel. The total value of the drive force and brake force applied to a turning outer steered road wheel of the vehicle is less than the total value of the drive force and brake force applied to a turning inner steered road wheel of the vehicle.

Description

TECHNICAL AREA

[0001] The present invention relates to a vehicle control device, a vehicle control method and a vehicle control system that control a vehicle equipped with a steer-by-wire system. TECHNICAL BACKGROUND

[0002] Recent developments in automated driving technologies have led to advances in the research and development of steer-by-wire (SbW) steering mechanisms. Reliability is crucial in steer-by-wire technology, which is why system redundancy is employed. However, such redundancy increases system costs. To address this issue, patent document 1, for example, describes how a cornering function is achieved by generating a vehicle yaw moment through the allocation of braking forces to individual wheels when the steering function of the SbW steering mechanism fails. LIST OF REFERENCES PATENT DOCUMENT

[0003] Patent Document 1: JP 2000-190863 A DESCRIPTION OF THE PROBLEM THAT THE INVENTION IS INTENDED TO SOLVE.

[0004] However, if the steering function malfunctions, controlling the vehicle's yaw moment alone does not necessarily guarantee the desired cornering maneuver, as the steering of the tires is influenced by the braking and driving forces (driving and braking forces) and the alignment.

[0005] This means that when braking force is applied to one of the front wheels to initiate a turn, the direction of travel changes based on the individual steering knuckle offset setting. For example, if braking force is applied to the right front wheel of a vehicle with a negative scrub radius for a right turn, the vehicle will turn in the opposite direction to the intended turn because the front wheels will steer to the left. In other words, the tires are steered in the direction that prevents the turn due to the braking force. Similarly, if braking force is applied to the left front wheel for a left turn, the tires will be steered in the direction that prevents the turn due to the braking force.

[0006] The present invention was made in view of the circumstances described above, and one object of the present invention is to provide a vehicle control device, a vehicle control method, and a vehicle control system that can achieve a cornering function including tire steering based on drive and braking forces. MEANS TO SOLVENT THE PROBLEM

[0007] In one aspect of the present invention, a vehicle control device and a vehicle control method are provided, wherein the vehicle control device is provided in a vehicle with a steer-by-wire system for steering right and left steered road wheels, which are mechanically separated from a steering wheel and whose steering roll radius is set to negative, wherein, when a control unit included in the vehicle control device detects an abnormal signal of a steering function in the steer-by-wire system, the control unit issues a first drive and brake command based on a steering operation entered at the steering wheel, such that, assuming that a drive force is a positive physical quantity and a brake force is a negative physical quantity, a total value of a drive force and a brake force is transmitted between the right and the left steered road wheels.the force applied to a turning outer steered road wheel of the vehicle is less than the sum of a driving force and a braking force applied to a turning inner steered road wheel of the vehicle.

[0008] In a further aspect of the present invention, a vehicle control system is provided which includes the vehicle control device and a drive and brake actuator which applies drive and brake forces to the right and left steered road wheels based on the first drive and brake command issued by the control unit. IMPACT OF THE INVENTION

[0009] The present invention enables cornering based on drive and braking forces not only by generating a vehicle yaw moment through the difference between the right and left drive and braking forces of a vehicle, but also by using tire steering based on the drive and braking forces acting on the individual road wheels and their alignment. Thus, the present invention can provide a vehicle control device, a vehicle control method, and a vehicle control system capable of cornering, including tire steering based on drive and braking forces. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 illustrates a configuration of a vehicle control device and a vehicle control system according to a first embodiment of the present invention. Fig. 2 is a flowchart that schematically represents a vehicle control procedure associated with the in Fig. 1 vehicle control device and vehicle control system is used. Fig. Figure 3A shows a vehicle movement based on drive and braking forces while driving around a curve. Fig. Figure 3B shows tire movement based on drive and braking forces while driving around a curve. Fig. Figure 4 shows a vehicle movement based on a different control method using drive and braking forces. Fig. Figure 5 shows another control method that uses driving and braking forces, i.e., a vehicle movement in which a driving force acting on a single road wheel can be controlled. Fig. Figure 6 illustrates a vehicle control device, a vehicle control method and a vehicle control system according to a second embodiment of the present invention, i.e. a flowchart that schematically illustrates a vehicle control method in which the tire angle is controlled and the steering is assisted when the steer-by-wire system is normal. Fig. Figure 7 shows a vehicle movement based on control by means of drive and braking forces in the Fig. 6 vehicle control methods shown. FORM OF EXECUTION OF THE INVENTION

[0010] The following describes embodiments of the present invention with reference to the drawings. Fig. Figure 1 shows a configuration of a vehicle control device and a vehicle control system according to an embodiment of the present invention. A vehicle 10 comprises a motor 72 that drives the front road wheels (tires) 11 and 12, and a motor 73 that drives the rear road wheels (tires) 13 and 14. The motors 72 and 73 function as drive actuators and drive the front road wheels 11 and 12 and the rear road wheels 13 and 14, respectively, based on the amount of actuation of an accelerator pedal 71. The amount of actuation is registered at a powertrain control unit 33.

[0011] In vehicle 10, the steering wheel 51 is not physically connected to the front road wheels (steered road wheels) 11 and 12. In other words, vehicle 10 is equipped with a steer-by-wire steering mechanism (steer-by-wire system) in which the steering wheel 51 and the front road wheels 11 and 12 are mechanically separated. This means that, unlike steering mechanisms known from the prior art, this steering mechanism does not have a steering shaft.

[0012] When the driver operates the steering wheel 51, a steering angle sensor 52 detects the steering angle, and a steering control unit 31 calculates a target wheel angle and a target reaction force based on the operating conditions. Next, the steering control unit 31 performs steering control by outputting the target wheel angle to a wheel actuator 42 and the target reaction force to a reaction force actuator 41, thus applying a steering reaction torque to the steering wheel 51.

[0013] In addition, a brake control unit 32 performs deceleration by means of brake actuators 15, 16, 17 and 18 based on the actuation amount of a brake pedal 61 and the output of brake thrust sensors 21, 22, 23 and 24, which detect the thrust generated by the deceleration.

[0014] The steering control unit 31, the brake control unit 32, and the powertrain control unit 33 function as control unit 30 of the vehicle control device. The steering control unit 31 detects a system malfunction. If the steering control unit 31 receives an abnormal signal from the steering function, the brake control unit 32 controls the braking forces applied by the brake actuators 15, 16, 17, and 18, and the powertrain control unit 33 controls the driving forces applied by the motors 72 and 73 based on the steering input registered at the steering wheel 51.

[0015] Next, the brake control unit 32 selectively issues a braking command to the brake actuators 15, 16, 17 and 18, and the powertrain control unit 33 selectively issues a drive command to the motors 72 and 73, so that between the right and left steered road wheels, the total value of the driving force and braking force applied to the turning outer steered road wheel of the vehicle 10 is less than the total value of the driving force and braking force applied to the turning inner steered road wheel of the vehicle 10.

[0016] Fig. 2 is a flowchart that schematically illustrates a vehicle control procedure associated with the in Fig. The vehicle control device shown in Figure 1 is used. When the ignition of the vehicle 10 is switched on, the steering control unit 31 performs a fault detection in the SbW system (step S1). The steering control unit 31 determines whether a fault has occurred that makes steering the wheels impossible (step S2). If such a fault has occurred, the steering control unit 31 calculates a target yaw rate (γ*) from the steering angle detected by the steering angle sensor 52 and a vehicle speed (V) (step S3). Next, the brake control unit 32 detects the amount of deduction of the brake pedal 61, the powertrain control unit 33 detects the amount of deduction of the accelerator pedal 71, and the steering control unit 31 calculates a target longitudinal acceleration (α). x *) (Step S4).

[0017] Next, the steering control unit calculates 31 target drive and braking forces (F). fl , F fr , F rl , and Frr ) of the individual road wheels from the target yaw rate (γ*) and the target longitudinal acceleration (α x *) (Step S5). Unless otherwise specified, the target drive and braking forces of the individual road wheels are subsequently combined as “F”. xx " designated.

[0018] Next, in step S6, the steering control unit 31 calculates the target drive and braking forces (F) from the desired drive and brake forces. xx ) the target braking forces (Tb) of the individual road wheels generated by the brake actuators 15, 16, 17 and 18 xx ) and the target drive torques (Tm) generated by motors 72 and 73 xx ).

[0019] Next, in step S7, the brake control unit 32 controls the brake actuators 15, 16, 17 and 18 based on the target braking forces (Tb). xx ) and the drive train control unit 33 controls the motors 72 and 73 based on the target drive torques (Tm) xx) on. Next, the process proceeds to its FINISH.

[0020] If, however, the steering control unit 31 determines in step S2 that a fault which makes steering the tire impossible has not occurred, the steering control unit 31 calculates a target tire angle (σ*) from the steering angle detected by the steering angle sensor 52 (step S8).

[0021] Next, the steering control unit 31 controls the wheel actuator 42 based on the target tire angle (σ*) (step S9). The process then proceeds to its FINISH.

[0022] The Fig. 3A and Fig. Figure 3B shows vehicle motion and tire motion based on drive and braking forces while cornering. The present example describes vehicle motion and tire motion when the steering scrub radius (γσ) of the front road wheels is negative (a single steering knuckle axis KP is located on the outside of the corresponding tire center). A moment (m BF2 The displacement of the steering knuckle axis when a braking force (BF2) is generated is expressed by the following equation (1). [Equation 1] mBF2=γδ*BF2

[0023] In addition, a moment (m SF ) about the steering knuckle axis when the tire angle is steered and a lateral force (SF) is generated, is expressed by the following equation (2) from the relationship with a caster (ζ). [Equation 2] mSF=ζ*SF

[0024] From equations (1) and (2) above, a tire angular acceleration (σ**) is expressed by the following equation (3). A tire angle (σ) is calculated by double integration of equation (3). [Equation 3] σ**=mBF2−2*mSFJs

[0025] The lateral force (SF) is calculated by the following equation (4) from the relationship between the tire angle (σ), which is calculated from the equation (3) above, the vehicle speed (V), the yaw rate (γ), the distance (l) f ) between the vehicle's center of gravity and the front axle, the vehicle's rut ​​angle (β) and the cornering performance (C) f ) of the front road wheels. [Equation 4] SF=Fyfl=Fyfr=−Cf(β+lfγV−δ)

[0026] A yaw moment (M c ), which is generated by the braking forces (BF1 and BF2) and the lateral force (SF) in the vehicle, is expressed by the following equation (5). [Equation 5] Mc=MBF1−MBF2+MST

[0027] As described above, driving a curve of vehicle 10 can be achieved by controlling the tire angle (σ) steered by the braking force (BF2) of the front road wheel in the above equation (1), a vehicle yaw moment (MST) generated from the lateral force (SF) generated from the tire angle (σ), a yaw moment (MBF2) generated by the braking force (BF2), and a vehicle yaw moment (MBF1) generated on the basis of the braking force (BF1) of the rear road wheel.

[0028] Alternatively, while cornering, the slip of the tire (right rear road wheel 14) can be increased by means of the braking force (BF1) of the rear road wheel in order to reduce the lateral force of the tire (right rear road wheel 14). Furthermore, the balance between the front road wheels and the lateral force can be altered to increase the yaw moment generated in the vehicle. In this way, the corner can be executed.

[0029] As described above, even if the steering function of a vehicle's steer-by-wire system malfunctions and its steering roll radius is negative, it is possible to steer the vehicle in the direction desired by the driver by reducing the driving and braking forces applied to the outer wheels to a lower value than those applied to the inner wheels (for example, by applying a greater force in the braking direction).

[0030] In the case of road wheels with a scrub radius setting, a braking force generates a moment in a direction that steers the tires. Specifically, with road wheels where the scrub radius is set to negative, the tires are steered in a direction that cancels out the vehicle yaw moment generated by the braking force (a lateral force is generated by tire steering, and a vehicle yaw moment is produced). In particular, a vehicle that is severely affected by the steering-induced yaw moment can be steered in a direction opposite to the expected direction of travel.

[0031] In a vehicle with these properties or characteristics, it is possible to achieve cornering by means of the lateral force generated by the steering, by reducing the total value of the driving and braking forces applied to the outer road wheels to such an extent that it is smaller than that acting on the inner road wheels.

[0032] In the present invention, a differential in drive and braking forces is generated for the front road wheels, depending on their orientation characteristics, to steer the tires. For the rear road wheels, because the effect of the orientation characteristics is relatively small, a differential in braking forces is generated to create a yaw moment for the vehicle.

[0033] In this way, the cornering function based on drive and braking forces can be achieved not only by generating a vehicle yaw moment by means of the drive and braking force difference with interfunctional redundancy in the event of a disturbance of the SbW, but also by achieving tire rotation by means of the alignment properties.

[0034] As described above, the vehicle can, using the vehicle control device, vehicle control method, and vehicle control system, steer a curve by means of tire rotation based on a braking force differential generated between the front wheels and based on the vehicle's orientation. The vehicle can also steer a curve or turn by generating a yaw moment through the braking force differential between the right and left rear wheels. In this way, the cornering function can be achieved by means of tire steering based on the braking force and the vehicle yaw moment.

[0035] Fig. Figure 4 illustrates vehicle movement based on a different control method using drive and braking forces. In this vehicle 10, the steering scrub radius is also set negatively. The moments about the steering knuckle axes of the front road wheels 11 and 12 are generated by the drive forces TF2 and TF1 and the braking force BF2. In particular, a drive force differential is generated by causing the motor 72 to produce torque, and consequently by actuating the brake actuator 15 of the left front road wheel 11. In this way, the front road wheels 11 and 12 are steered in the direction of travel, and the braking force BF1 applied to the right rear road wheel 14 generates a vehicle yaw moment, causing the vehicle 10 to turn.

[0036] When the driving and braking forces are used, they are assigned in such a way that the target longitudinal acceleration (α) x *) is achieved. If the target longitudinal acceleration (α) is reached. x *) if this cannot be achieved, the driving and braking forces of the individual road wheels are assigned, for example, in such a way that the generated longitudinal acceleration decreases towards the deceleration side in order to complete the necessary cornering maneuver.

[0037] If the force that can be generated by a single road wheel is saturated, for example due to a change in load, the driving and braking forces are reallocated so that another road wheel can generate force. For example, if in Fig. 4. When the braking force BF1, which can be generated by the right rear road wheel 14, is saturated, the driving and braking forces are allocated in such a way that the left rear road wheel 13 can generate a driving force.

[0038] Furthermore, if a single road wheel detects a slip with a predetermined value or more, the drive and braking forces are reallocated in such a way that the slip will not worsen.

[0039] Fig. Figure 5 illustrates another control method using drive and braking forces, i.e., vehicle movement when a drive force acting on a single road wheel can be controlled. This example is applied to vehicle 10, which has so-called in-wheel motors, i.e., motors 81, 82, 83, and 84, installed for the respective road wheels. Vehicle 10 also has a negative steering scrub radius. Vehicle 10 uses motors 81 and 82. Specifically, motor 82 generates the drive force TF1 to produce a moment about the steering knuckle axis of the right front road wheel 12. By generating a drive force differential in this way, the front road wheels 11 and 12 are steered. Vehicle 10 also uses motors 83 and 84.A vehicle yaw moment is generated in particular by the braking force BF1 applied by the brake actuating device 18 of the right rear road wheel 14 and the driving force applied by the motor 83 of the left rear road wheel. As a result, the vehicle 10 travels in a curve.

[0040] Fig. Figure 6 shows a vehicle control device, a vehicle control method, and a vehicle control system according to a second embodiment of the present invention, i.e., a flowchart schematically representing a vehicle control method. In the present second embodiment, when the steer-by-wire system is normal, the tire angle is controlled and the steering is assisted.

[0041] First, the steering control unit 31 calculates the target tire angle (σ*) from the steering angle detected by the steering angle sensor 52 (step S11).

[0042] Next, the steering control unit 31 calculates a tire angle deviation (σ). e ) from the difference between the target tire angle (σ*) and the tire angle (σ) (step S12).

[0043] Next, the brake control unit 32 detects the amount of actuation of the brake pedal 61, the powertrain control unit 33 detects the amount of actuation of the accelerator pedal 71, and the steering control unit 31 calculates the target longitudinal acceleration (α). x *) (Step S13).

[0044] Next, the steering control unit 31 calculates the target drive and braking forces (F fl , F fr , F rl , F rr ) of the individual road wheels from the tire angle deviation (σ e ) and the target longitudinal acceleration (α x *) (Step S14). Unless otherwise specified, the target drive and braking forces of the individual road wheels are subsequently referred to collectively as “F”. xx " designated.

[0045] The steering control unit 31 then calculates the target drive and braking forces (F) from the specified drive and braking forces. xx ) the target braking forces (Tb) of the individual road wheels xx ), which are generated by the brake actuators 15, 16, 17 and 18, and the target drive torques (Tm xx ), which are generated by motors 72 and 73 (step S15).

[0046] Next, the brake control unit 32 controls the brake actuators 15, 16, 17 and 18 based on the target braking forces (Tb). xx ) and the drive train control unit 33 controls the motors 72 and 73 based on the target drive torques (Tm) xx ) on (step S16).

[0047] Next, the steering control unit 31 controls the wheel actuator 42 based on the tire target angle (σ) (step S17).

[0048] According to the control method described above, it is possible to assist the steering by controlling the tire angle. Furthermore, according to the present second embodiment, the steering assistance can also be applied to a steering system (EPS) that is not based on a steer-by-wire (SbW) method if the steering roll radius of the steered road wheels is negative.

[0049] Fig. Figure 7 illustrates vehicle movement based on control via drive and braking forces in the Fig.The vehicle control method shown in Figure 6 is used. To generate the moments about the steering knuckle axes of the front road wheels 11 and 12, which are the steered road wheels, with the driving forces TF2 and TF1, and the braking force BF2, a torque is generated by the motor 72. By actuating the brake actuator 15 of the left front road wheel 11, a driving force differential is generated, thereby assisting the steering of the front road wheels 11 and 12.

[0050] If the driving and braking forces are used, the driving and braking forces are assigned such that the target longitudinal acceleration (α) x *) is achieved. If the target longitudinal acceleration (α) is reached. x *) cannot be achieved, for example a drive and brake force difference up to the target longitudinal acceleration (α) will be used. x *) used to assist tire steering.

[0051] According to the configurations and procedures described above, a vehicle corners by means of a braking force differential generated between the front wheels and orientation-based tire steering, and also corners by generating a yaw moment through a braking force differential between the right and left rear wheels. Thus, even if the SbW tire steering function malfunctions, a cornering maneuver requested by the system can be achieved using drive and braking forces, regardless of the vehicle's orientation. Furthermore, by achieving the cornering function based on drive and braking forces, independent of orientation characteristics, SbW redundancy can be reduced, leading to lower costs.As a result, it is possible to obtain a vehicle control device, a vehicle control method and a vehicle control system that can achieve a cornering function by means of tire steering based on braking force and by means of a vehicle yaw moment.

[0052] The configurations, methods, etc., in the first and second embodiments described above have only been described schematically to the extent necessary to understand and implement the present invention. Therefore, the present invention is not limited to the embodiments described above. The present invention can be modified in various ways without deviating from the scope of protection of the technical concepts specified by the claims.

[0053] Although, for example, the steering control unit 31 calculates the target longitudinal acceleration in the embodiments described above, another control unit within the control unit 30 can also calculate the target longitudinal acceleration. Furthermore, the calculations performed by the individual control units 31, 32, and 33 within the control unit 30 can, of course, also be performed by another control unit. A dedicated control unit can be provided to achieve the cornering function if the steering function fails. LIST OF REFERENCE MARKS 10 vehicles 11 front road wheel (tire) 13 rear road wheel (tire) 15, 16, 17, 18 Brake actuator 21, 22, 23, 24 Brake thrust sensor 30 Control unit 31 Steering control unit 32 Brake control unit 33 Powertrain control unit 41 Reaction force actuator 42 Wheel actuator 51 Steering wheel 52 Steering angle sensor 61 Brake pedal 71 Accelerator pedal 72, 73, 81, 82, 83, 84 Engine QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2000-190863 A

[0003]

Claims

[1] Vehicle control device provided in a vehicle with a steer-by-wire system for steering right and left steered road wheels which are mechanically separated from a steering wheel and whose steering roll radius is set to negative, wherein, when a control unit included in the vehicle control device detects an abnormal signal of a steering function in the steer-by-wire system, the control unit issues a first drive and brake command based on a steering operation entered at the steering wheel, such that, assuming that a drive force is a positive physical quantity and a brake force is a negative physical quantity, the total value of a drive force and a brake force applied to a turning outer steered road wheel of the vehicle is less than the total value of a drive force and a brake force.which is applied to a turning inner steered road wheel of the vehicle. [2] Vehicle control device according to claim 1, wherein the steered road wheels are front road wheels. [3] Vehicle control device according to claim 2, wherein the control unit, based on a steering operation entered at the steering wheel, issues a second drive and brake command, such that, assuming that a drive force is a positive physical quantity and a brake force is a negative physical quantity, the total value of a drive force and a brake force applied to a turning inner rear wheel of the vehicle is less than the total value of a drive force and a brake force applied to a turning outer rear wheel of the vehicle. [4] Vehicle control device according to claim 3, wherein the control unit, based on a steering operation entered at the steering wheel, issues a slip control command to increase the slip amount of a turning inner rear road wheel of the vehicle between the right and left rear road wheels. [5] Vehicle control device according to claim 2, wherein the first drive and brake command is a command to apply a braking force to a turning outer front road wheel of the vehicle. [6] Vehicle control device according to claim 2, wherein the first drive and brake command is a command to apply a drive force to a turning inner front road wheel of the vehicle. [7] Vehicle control device according to claim 2, wherein the first drive and brake command is a command to apply a drive force and a brake force to a turning outer front road wheel of the vehicle and to apply a drive force to a turning inner front road wheel of the vehicle. [8] Vehicle control device according to claim 3, wherein the first drive and brake command is a command to apply a braking force to a turning outer front road wheel of the vehicle, and wherein the second drive and brake command is a command to apply a driving force to a turning outer rear road wheel of the vehicle and to apply a braking force to a turning inner rear road wheel of the vehicle. [9] Vehicle control device according to claim 3, wherein the first drive and brake command is a command to apply a driving force to a turning inner front road wheel of the vehicle, and wherein the second drive and brake command is a command to apply a driving force to a turning outer rear road wheel of the vehicle and to apply a braking force to a turning inner rear road wheel of the vehicle. [10] Vehicle control device according to claim 3, wherein the first drive and brake command is a command to apply a driving force and a braking force to a turning outer front road wheel of the vehicle and to apply a driving force to a turning inner front road wheel of the vehicle, and wherein the second drive and brake command is a command to apply a driving force to a turning outer rear road wheel of the vehicle and to apply a braking force to a turning inner rear road wheel of the vehicle. [11] Vehicle control method performed by a control unit provided in a vehicle having a steer-by-wire system for steering right and left steered road wheels which are mechanically separated from a steering wheel and whose steering roll radius is set to negative, wherein, when the control unit detects an abnormal signal of a steering function in the steer-by-wire system, the control unit issues a first drive and brake command based on a steering input applied to the steering wheel, such that, assuming that a drive force is a positive physical quantity and a brake force is a negative physical quantity, the total value of a drive force and a brake force applied to a turning outer steered road wheel of the vehicle is less than the total value of a drive force and a brake force.which is applied to a turning inner steered road wheel of the vehicle. [12] Vehicle control system which features: a steer-by-wire system for steering right and left steered road wheels that are mechanically separated from a steering wheel; a control unit provided in a vehicle with right and left steered road wheels, the steering roll radius of which is set to negative; and a drive and brake actuator which, based on an initial drive and brake command, applies drive and brake forces to the right and left steered road wheel, wherein, if the control unit detects an abnormal signal of a steering function in the steer-by-wire system, the control unit issues the first drive and brake command based on a steering input entered at the steering wheel, such that, assuming that a drive force is a positive physical quantity and a brake force is a negative physical quantity, the total value of a drive force and a brake force applied to a turning outer steered wheel of the vehicle is less than the total value of a drive force and a brake force applied to a turning inner steered wheel of the vehicle. [13] Vehicle control device with a steer-by-wire system for steering right and left steered road wheels which are mechanically separated from a steering wheel, wherein, based on a steering input entered at the steering wheel and based on a setting of a steering roll radius of the steered road wheels, a control unit included in the vehicle control device calculates a drive and brake command, such that, assuming that a drive force is a positive physical quantity and a brake force is a negative physical quantity, between the right and left steered road wheels either a total value of a drive force and a brake force applied to a turning outer steered road wheel of a vehicle or a total value of a drive force and a brake force applied to a turning inner steered road wheel of the vehicle is greater than the other,and outputs the calculated drive and brake command.

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