Abstract: A rotational angle sensor used in an electric power steering apparatus detects a rotational angle of a motor shaft at a portion on a steering system side, as a motor rotational angle (?m). A MPU sets a base correction amount (???m) based on a q-axis actual current value (Iq). The MPU sets a rotational angle correction amount (??m) used to correct the motor rotational angle (?m) by decreasing the base correction amount (???m) as a rotational angular speed (?) increases and by increasing the base correction amount (???m) as a torque differential value (dT/dt) increases.

Abstract: A vehicle steering apparatus includes a vehicle steering system and a supplemental steering force applying device. The supplemental steering force applying device is configured and arranged to apply a supplemental steering force to the vehicle steering system to reduce a steering load on the operator. The supplemental steering force applying device includes a steering torque detecting section, a rectilinear driving condition detecting section, a pulling suppression control section. The rectilinear driving condition detecting section is configured and arranged to detect a rectilinear driving condition of the vehicle. The pulling suppression control section is configured and arranged to adjust the supplemental steering force in a direction canceling a pulling force imparted on the vehicle during the rectilinear driving condition by using a pulling suppression force calculated based on historical data of the steering torque detected during the rectilinear driving condition.

Abstract: In a remote control system, the remote control of a vehicle function is executed. The remote control system includes a control terminal and a cancellation device. The control terminal transmits a request for the remote control of the vehicle function to a vehicle. The cancellation device cancels the remote control of the vehicle function if the local control of the vehicle function is requested before the remote control of the vehicle function is executed according to the request for the remote control.

Abstract: A power steering apparatus has a steering power assisting system coupled to tire wheels and a variable gear transfer system coupled to a steering wheel. The steering power assisting system includes a torsion bar rotation sensor and a first actuator rotation sensor to calculate a first pinion angle and a second pinion angle based on the detected rotation angles, respectively. The variable gear transfer system includes a steering sensor and a second actuator rotation sensor to calculate a third pinion angle based on the detected rotation angles. Sensor failure is detected by comparing the calculated first, second and third pinion angles.

Abstract: A steering control apparatus is provided for a vehicle having a steering wheel for steering steered wheels of the vehicle, a power source for generating power, and drive shafts for transferring the power to the steered wheels, to be served as driving wheels of the vehicle. The apparatus comprises an accelerating operation detection device for detecting accelerating operation amount by a vehicle driver, and a steering torque control device for controlling steering torque created by the steering wheel, and applying torque steer reducing torque to the steering wheel. The steering torque control device is adapted to reduce torque steer, which is transiently created on the steering wheel due to characteristics of the drive shafts, when the accelerating operation amount detected by the accelerating operation detection device becomes equal to or greater than a predetermined value.

Abstract: When a current input to a step-up voltage device of an electric power steering apparatus is equal to or higher than a first threshold current and an input voltage applied to the step-up voltage device is lower than a first threshold voltage, the step-up voltage device of the electric power steering apparatus discontinuously switches an output voltage to a voltage lower than a rated step-up voltage. When the input voltage becomes lower than a second threshold voltage which is lower than the first threshold voltage, the step-up voltage device sets the output voltage to a voltage equal to the input voltage.

Abstract: An electric power steering apparatus including a steering torque detecting section configured to detect a steering torque applied to an operation member for steering a vehicle, a steering state judging section configured to determine whether forward stroke steering that steers the operating member away from a steering angle midpoint is performed, a motor controlling section configured to control the driving of an electric motor based on the steering torque detected by the steering torque detecting section, and a phase compensating section provided in the motor controlling section for performing phase compensation, such that, when the forward stroke steering is not performed according to the steering state judging section, a gain in a predetermined frequency band in frequency response characteristics of the phase compensation is lower than gains in frequency bands lower and higher than the predetermined frequency band, and is lower than a gain in the predetermined frequency band when the forward stroke steerin

Abstract: A vehicle steering apparatus for improving steering feel when changing the angle of a steered wheel with a motor. An IFS torque compensation unit includes an oversteer IFS torque compensation gain calculation unit, which obtains a larger IFS torque compensation gain as a control target element increases during oversteer control. When an oversteer state occurs, the IFS torque compensation control unit outputs a corrected gain, which is based on the IFS torque compensation gain.

Abstract: A method and system for onboard zero offset compensation for ATV electric power assist steering (EPAS) torque sensor. An electric assist torque can be applied to an EPAS motor in a clockwise and a counterclockwise direction until a movement is generated in a steering column. A threshold value of torque signal generated by the torque sensor in both directions can be stored when the applied torque exceeds a reaction torque to cause acceleration of a shaft. The reaction torque can be determined under conditions such as, for example, when no one is holding the handle bars and the wheels are free from obstruction. The magnitude of the torque signals are approximately equivalent and an absolute magnitude of the torque signals falls below a general torque limit that can be set under ideal conditions with the ATV. Thereafter, an auto zeroing operation can be performed a number of times throughout the life of the ATV and the error due to offset drift of the sensor can be reduced.

Abstract: A vehicle steering device and control method for use in steer-by-wire steering systems. A steering instrument is operable to receive input from a driver and a turning device is operable to turn at least one wheel. A selectively engageable backup clutch is positioned between the steering instrument and the turning device. Engagement of the backup clutch results in a mechanical connection between the steering instrument and the turning device for assisting control of the at least one wheel, and release of the backup clutch results in a separation of the steering instrument and the turning device for steer-by-wire control of the at least one wheel. A controller is operable to switch from the steer-by-wire control to the assisting control when the backup clutch engages during operation of the steer-by-wire control.

Abstract: While a steering angle speed which represents a steering speed of the steering wheel is equal to or smaller than a predetermined speed, i.e., while the vehicle is making a steady turn with the steering wheel being held at a given angle or while the vehicle is running straight, when the rate of change of a rack load calculated by a rack load rate-of-change calculator becomes equal to or greater than a predetermined value, an EPS motor is supplied with a corrective current or which serves as a corrective signal for a drive signal in a direction to cancel out the rate of change of the rack load.

Abstract: The ratio of the angular speed of a pinion shaft to the angular speed of a steering wheel is computed. The steering torque Tst transferred to the steering wheel is computed as a multiplication product of the ratio of angular speed and the steering torque Tm of the pinion shaft. The steering torque ?Tst transferred to the steering wheel due to actuation of a steered wheel turning angle variable device is computed as a value obtained by subtracting the steering torque Tm from the steering torque Tst. An electric power steering control device is controlled so as to generate a steering torque fluctuation-reducing assist torque corresponding to the steering torque ?Tst.

Abstract: A motor-driven steering assist apparatus includes a single unit body covered by first to third housings, an upper end portion of an input shaft and a torque sensor are supported to the first housing, an upper end portion of an output shaft, an electric motor, a worm gear and a worm wheel are supported to the second housing, and a lower end portion of the output shaft is supported to the third housing.

Abstract: In a steering apparatus for a vehicle, a target sub steering angle ?SREF is set by a target-sub-steering-angle setting unit on the basis of an output ?H of a steering-wheel-angle detection unit and a transmission characteristic f(?H) of a transmission-characteristic setting unit, and a target current IREF is set by a target-current setting unit on the basis of the target sub steering angle ?SREF and an output ?S of the sub-steering-angle detection unit. Current control unit controls a current which flows through an electric motor of a sub-steering-angle superposition mechanism, so that the target current IREF and a current IS of current detection unit may agree.

Abstract: A method of operating a vehicle at a substantially low speed based on change in the vehicle position. The method comprises the following steps: (A) transforming a steering control algorithm into a substantially low speed (SLS) steering control algorithm, wherein the (SLS) steering control algorithm is configured to operate the vehicle in an asynchronous low speed mode; and (B) implementing the SLS steering control algorithm as a controller configured to operate the vehicle in the asynchronous low speed mode.

Abstract: The steering control device performs a control of applying an assist torque based on a steering by a driver. Concretely, the steering control device sets a transfer function from an inputted steering angle to a wheel turning angle to a predetermined frequency response. Then, the steering control device determines the assist torque corresponding to a steering amount based on the frequency response, a transfer function of the steering angle in a relational formula between the steering angle, the wheel turning angle and the assist torque, and a transfer function of the assist torque in the relational formula. By executing the steering assist based on the determined assist torque, it becomes possible to control the response of the wheel turning angle to the steering angle with high accuracy.

Abstract: An ECU determines whether the orientation of the vehicle is deflecting at the time of braking. In addition, in a case where it is determined that the orientation of the vehicle is deflecting, the ECU controls operation of an EPS actuator in order to reduce the assist force provided to the steering system.

Abstract: The invention relates to a steering system of a motor vehicle with a rack, which is connected on the end side with steerable wheels and which pivots said wheels through a lateral movement. The steering system has a position sensor which continuously determines the position of the rack and emits corresponding position signals.

Abstract: A motor-driven steering controller for controlling a steering wheel of a vehicle. The controller includes a steering torque controlling unit, a braking force estimating unit, a right and left braking force difference estimating unit and an assist steering torque providing unit. The steering torque controlling unit controls a steering torque on the steering wheel depending on a steering operation. The braking force estimating unit estimates braking forces to be imposed on wheels of the vehicle. The right and left braking force difference estimating unit estimates difference between the braking forces to be imposed on the right and left wheels each estimated by the braking forces estimating unit. The assist steering torque providing unit provides an assist steering torque for the steering torque controlling unit on the basis of the difference in braking force between right and left wheels estimated by the right and left braking force difference estimating unit.

Abstract: When it is determined that a malfunction has occurred in a rotational angle sensor, an electronic control unit changes the control manner from the normal assist control to the sensorless assist control. In the sensorless assist control, an assist stop command unit receives the information concerning the motor rotational angular speed ?m from an angular speed conversion unit. Then, the motor rotational angular speed ?m is compared with the threshold value ?m1. If the motor rotational angular speed ?m is equal to or higher than the threshold value ?m1, an assist enabling signal is transmitted to a PWM voltage production unit to continue the power assist. On the other hand, if the motor rotational angular speed ?m is lower than the threshold value ?m1, a stop command signal is transmitted to the PWM voltage production unit to stop the power assist.

Abstract: In a power supply circuit, first and second loads are connected in parallel to a power source though first and second power lines, respectively. A power line connector connects the first and second power lines together in such a manner that even when one of the first and second power lines is broken, the first and second loads are supplied with electric power from the power source through the other of the first and second power lines. A rectifier device is connected to each of the first and second power lines between the power source and the power line connector. The rectifier device allows an electric current in a direction from the power source to the first and second loads and blocks the electric current in opposite direction.

Abstract: An electric power steering system includes an electric assist motor, a controller, a first corrector, and a second corrector. The electric assist motor is configured to assist steering according to a steering assist amount. The controller is configured to control the steering assist amount in accordance with an input steering force. The first corrector is configured to correct the steering assist amount with a correction amount in accordance with a steering torque during running on a cant road. The second corrector is configured to correct the correction amount in accordance with a steering angular velocity.

Abstract: A vehicular steering system can suppress, even upon a change in a neutral position of a steering wheel, a right and left difference in the behavior of a vehicle by keeping neutral positions of steerable road wheels from the start of control. The system includes a steering mechanism that steers the steerable road wheels of the vehicle through the steering wheel and an auxiliary steering angle superposition mechanism. A steered angle of the steerable road wheels is detected as an absolute angle. The auxiliary steering angle superposition mechanism is controlled by a target auxiliary steering angle. An activation angle setting section sets, at the start of control, the initial values of a steering wheel angle and an auxiliary steering angle as an activation steering wheel angle and an activation auxiliary steering angle by the steered angle and a transmission characteristic between the steering wheel angle and the steered angle.

Abstract: An electromechanical steering device for a motor vehicle having at least one electric motor and power electronics for controlling the electric motor includes at least one temperature sensor for measuring the temperature of the power electronics and/or the ambient temperature of the power electronics and switching times of the power electronics are variable as a function of the measured temperature.

Abstract: An approved apparatus (10) for turning steerable wheels (14,16) of a vehicle includes a pinion (28) which is disposed in meshing engagement with a rack portion (32) of a steering member (12). A steering column (22) is connected with a pinion (28) and with a vehicle steering wheel (20). A ball nut assembly (38) is connected with an externally threaded portion (36) of the steering member (12). A first motor (72) is connected with the steering column (22) at a location between the pinion (28) and steering wheel (20). A second motor (48) is connected with the ball nut assembly (38). A closed loop assembly (60) may be provided to control operation of the first motor (72). An open loop assembly (82) may be provided to control operation of the second motor (48).

Abstract: In an electric power assisting system for a vehicle, a control unit receives an input shaft rotation angle detected by an input shaft rotation angle sensor and an output shaft rotation angle detected by an output shaft rotation angle sensor. The control unit controls rotation of a motor based on the detected two rotation angles. The control unit differently controls the rotation of the motor whether torque is applied from a steering wheel side or from a road surface side.

Abstract: An electric power steering apparatus is provided for suppressing the effect on the steering wheel of external interference inputted from the tie rod. The apparatus includes first and second output units for outputting first and second control amounts in accordance with the outputted torque signal, except in a dead zone thereof, respectively. The apparatus also includes gain data output units for, when the torque signal, a steering angular velocity, and a vehicle speed are within predetermined ranges, outputting gain data respectively. Steering operation is assisted by an electric motor driven on the basis of the first and second control amounts and the gain data, which afford a control signal to the motor.

Abstract: A steering device for a vehicle includes a planet gear mechanism which can vary transmission ratio, and a lock mechanism for fixing the transmission ratio. The planet gear mechanism includes a first sun gear connected to a steering member, a second sun gear connected to turning wheels, a planet gear which is meshed with both the first and second sun gears and a carrier in an annular shape which supports the planet gear. The lock mechanism includes a restraining member which is engageable with the carrier thereby to restrain rotation of the carrier.

Abstract: Since a rigid supporting structure for a gear box GB and a rolling type rack supporting device RSD are employed, an electric power steering apparatus having no response delay and having a high transmission efficiency can be realized. Further, a high steering performance required for a long period and a steering assist force that is increasing recently can be efficiently transmitted to wheels. Further, when the wheels collide with a shoulder of a road to receive a counter input, a torque sensor TS detects a torque and an assist steering force against the counter input is outputted to an output shaft OS. Consequently, the torque of the counter input is restrained from being transmitted to a steering shaft SS side. Thus, a kick back and a vibration are advantageously hardly transmitted to a steering wheel SW from the wheels.

Abstract: An electric power steering device, including an electric motor supplied with power from a power supply device to generate a predetermined steering assistance force for a steered wheel, and an assistance control device the controls the amount of electrical power supplied to the electric motor, according to the steering state of a steering wheel. The assistance control device detects the power supply voltage of the power supply device. The assistance control device controls the electrical current supplied to the electric motor, so as to maintain the power supply voltage greater than or equal to a set voltage which is set in advance.

Abstract: In a control method for a motor 10 for generating a reaction force when a driver operates a steering wheel, as a behavior of a vehicle increases, a larger reaction force to the behavior is generated. When an anti-lock brake system is operated, the reaction force to the behavior is corrected so as to be large.

Abstract: A vehicle steering control system for a vehicle/trailer combination that provides rear-wheel steering assist to improve the vehicle/trailer combination stability and handling performance. The control system provides an open-loop feed-forward control signal based on hand-wheel angle and vehicle speed. The control system includes a vehicle yaw rate command interpreter that provides a vehicle closed-loop feedback control signal based on the yaw rate of the vehicle, a trailer yaw rate command interpreter that provides a trailer closed-loop feedback control signal based on the yaw rate of the trailer, and a vehicle lateral acceleration command interpreter that provides a closed-loop feedback control signal based on the lateral acceleration of the vehicle. The closed-loop feedback signals are added together and then combined with the open-loop feed-forward control signal to provide the rear-wheel steering assist.

Abstract: An electric power steering apparatus includes: a motor for providing assistant steering power; a following pulley connected with the motor through a belt to receive a driving force; a gear housing surrounding the following pulley; a motor housing rotatably assembled with the gear housing; and a tension adjusting mechanism for adjusting a rotation angle of the motor housing so as to adjust a tension of the belt. Therefore, the relative rotation angle of the motor housing respective to the gear housing can be adjusted so that the tension of the belt can be easily controlled and the generation of vibration and noise of the belt can be prevented.

Abstract: A magnetostrictive torque sensor comprising: a magnetostrictive film provided on a ferromagnetic shaft; a bias magnetization device which applies a bias magnetic field to the shaft to magnetize the shaft; and a detection device which detects a change in magnetism of the magnetostrictive film, wherein: a torque acting on the shaft calculated based on the detection results of the detection device; and the bias magnetization device applies a bias magnetic field to the shaft at a predetermined timing.

Abstract: An electric power steering system includes a multi-phase electric motor, an inverter connected to the rotary electric machine and an electronic control apparatus. One phase of the motor is pulled up by a resistor. The electronic control apparatus detects disconnection abnormality between the motor and the inverter by checking phase voltages of the inverter by stopping the inverter operation. If disconnection is detected, current is supplied to the remaining normal two phases. The electronic control apparatus detects short-circuit abnormality by checking an electric angle (rotation angle) of the motor.

Abstract: An electric power steering device for automotive vehicles which is capable of minimizing a driver's steering effort. The electric power steering device is designed to perform an automatic steering control. When a steering effort has fallen within a range of steering effort within which the driver is expected to have started to turn a steering wheel intentionally, the automatic steering control is initiated. When the steering effort has been shifted from that range, the automatic steering control is deactivated. This permits the driver's steering effort to be minimized as needed by the driver.

Abstract: An electric power steering apparatus is configured in such a way as to include a first filtering unit that applies filtering processing to the detected steering torque signal and outputs the processed torque signal; a control unit that generates and outputs a motor drive signal, based on a steering torque signal outputted from a first filtering unit; a second filtering unit that applies filtering processing to the detected steering torque signal and outputs the processed torque signal; and an interlock unit that generates and outputs a motor drive inhibition signal, based on the steering torque signal outputted from the second filtering unit. The second filtering unit performs filtering processing in such a way as to output a steering torque signal the same as or similar to the steering torque signal that is outputted from the first filtering unit at least when a vehicle is in a predetermined driving condition.

Abstract: A steering system arranged in a vehicle having a steering wheel, a steering system control unit and a steering assistance unit with an electric motor. The steering system is designed to assist, by the motor of the steering assistance unit, a predefined steering movement of a driver at the steering wheel for steering steerable wheels of the vehicle and to steer the steerable wheels in accordance with the predefined steering movement. In this context, the steering wheel is mechanically coupled to the steering assistance unit. The steering system is also designed to block a predefined steering movement at the steering wheel, and therefore to block steering of the steerable wheels by the steering assistance unit, in a predefined state of rest of the vehicle.

Abstract: According to the present invention, unlike to motor-driven power steering systems in the related art, it is possible to generate an appropriate assistant steering force that is required to drive the motor according to steering of the driver, without expensive components, such as a torque sensor and an electronic controller, such that it is possible to achieve a motor-driven power steering system having a simple structure at a low cost.

Abstract: The system and method described herein can be used to reduce the effects of periodic vibrations in an electric power steering (EPS) system for a vehicle, particularly, those that can lead to smooth road shake (SRS), torsional nibble, and/or other undesirable conditions. According to an exemplary embodiment, an electric motor is used to purposely generate counter-acting vibrations in the EPS system to cancel out the periodic vibrations generated by the wheel assemblies or corners.

Abstract: An electric power steering control apparatus can limit a motor impression voltage thereby to maintain an appropriate motor output even upon occurrence of a failure of a motor current detection circuit or a motor current feedback control system. The apparatus includes a motor that generates an assist force to the steering system, an input processing section that takes in a steering torque signal from a torque sensor, an output processing section that drives the motor, and a processing unit that provides an instruction to the output processing section based on the steering torque signal. The processing unit includes an impression voltage calculation section that calculates an amount of operation to the motor in accordance with the steering torque signal, and an impression voltage limiting section that limits the impression voltage to predetermined limit values or less corresponding to the direction of the steering torque signal.

Abstract: An electric power steering system for a vehicle includes a motor for providing assistance in turning the wheels of the vehicle. The motor is electrically connected to a controller. The controller includes a power device, such as a power transistor, electrically connected to the motor to variably provide electric power to the motor as needed. The controller also includes a gate drive device electrically connected to the power device for regulating operation the power device. A shutdown mechanism is electrically connected between the gate drive device and a power input. In the event of a fault, the shutdown mechanism isolates electrical power from the gate drive device. This prevents the power device from providing electric power to the power steering motor.

Abstract: A control unit including a plurality of boards is formed of a single multilayer metal substrate, whereby an electric power steering apparatus can be obtained in which connection members for connecting between the boards are made unnecessary, so the size and cost of the apparatus can be reduced, and the reliability of bonding can be improved. In the electric power steering apparatus, a power main body (20a) and a control main body (20b) are mounted on a metal substrate (22), and the power main body (20a) and the control main body (20b) are electrically connected to each other by wiring patterns (26a through 26e) and metal columns 28a through 28d in the metal substrate 22.

Abstract: A vehicle steering system including: (a) a steering operation member; (b) a movement-amount variably transmitting device including: (b-1) a housing fixed to a vehicle body; (b-2) a differential mechanism including (i) a first element connected to the steering operation member, (ii) a second element movable relative to the first element, and (iii) a third element engaged with the first and second elements; and (b-3) a drive source for moving the third element, such that an amount of relative movement of the first and second elements is changeable depending on an amount of movement of the third element; and (c) a wheel turning device connected to the second element to turn a vehicle wheel. The movement-amount variably transmitting device further includes (b-4) a third-element-movement inhibiting device for inhibiting movement of the third element. The steering system further includes (d) a third-element-movement inhibition cancelling device for cancelling inhibition of the movement of the third element.

Abstract: The invention relates to a method for controlling the driving stability of a vehicle, wherein it is determined when a stable or unstable driving behavior prevails whether a tendency to a subsequent unstable driving behavior exists as a result of a highly dynamic inward swerve. In order to provide a method for controlling driving stability, which allows a reaction to predicted unstable driving situations by means of an intervention diminishing or avoiding critical driving situations, the steering force and/or the steering angle of a steering handle is corrected in this case in such a manner that when the steering handle is operated, the driver is assisted in the direction of an understeering vehicle course.

Abstract: An electric power steering device that can estimate an ambient temperature and apply current limiting without using ambient temperature detecting means is provided. The electric power steering device includes a motor that supplements the driver's steering force, a controller that determines and controls the quantity of current passed to the motor, and vehicle speed detecting means. The electric power steering device includes ambient temperature estimating means provided with a vehicle speed signal input from the vehicle speed detecting means and limits the quantity of current passed to the motor according to an output from the ambient temperature estimating means.

Abstract: An on-vehicle motor control device includes a power switching circuit disposed on a circuit board to supply current from a battery to a motor, a microcomputer disposed on the same circuit board that controls the power switching circuit in a PWM control mode to minimize the difference between the current supplied to the motor and a preset current. The microcomputer decreases the preset current when the battery voltage is higher than an upper limit or when both the battery voltage and the voltage of the ignition key signal are higher than respective upper limits.

Abstract: In an electric power steering system for a vehicle that controls a force that urges a steering wheel toward a neutral position thereof, a control unit (21) for the system is configured such that an electric motor (9) for providing an assisting force produces a relatively large returning force when a rotational direction of a steering wheel (2) agrees with a direction of the steering torque applied to the road wheel (7), and a relatively small returning force when a rotational direction of the steering wheel disagrees from a direction of the steering torque applied to the road wheel. Thereby, the effort required for a vehicle operator to steer the vehicle is reduced and the steering feel can be thereby and otherwise improved while providing a favorable returning force that urges a steering wheel toward a neutral position.

Abstract: In a controller for an electric power steering apparatus, a target value calculation element, which calculates target values of the drive currents of a motor on the basis of a detected value of the steering torque, is constituted by a first integrated circuit provided in a chip. A drive signal value calculation element, which calculates drive signal values for driving the motor on the basis of the target values calculated by the target value calculation element, detected values of the drive currents of the motor, and a detected value of the rotary position of a rotor of the motor, is constituted by a second integrated circuit provided in another chip from the chip. A driving element drives the motor in accordance with the drive signal values. The first integrated circuit is connected communicably to the second integrated circuit. The calculation cycle of the drive signal values is set to be shorter than the calculation cycle of the target values.

Abstract: A driving force distribution control unit 60 calculates front/rear driving force distribution cooperative control addition yaw moment by multiplying front/rear driving force distribution control addition yaw moment by a front/rear driving force distribution cooperative control gain. Under steering accelerating condition, when it is possible to judge that actual lateral acceleration is high and the road is a high ? road, the front/rear driving force distribution cooperative control gain is set to become a low control gain so as to reduce a control amount by the front/rear driving force distribution control operation. Also, the driving force distribution control unit 60 calculates right/left driving force distribution cooperative control addition yaw moment by multiplying right/left driving force distribution control addition yaw moment by a right/left driving force distribution cooperative control gain.