Honda Giken Kogyo Kabushiki Kaisha

Honda Motor Co., Ltd.

Takashi Nishimori

Yutaka Nishi

Hiroyuki Tokunaga

Yorihisa Yamamoto

Hideki Machino

Hiroyuki Kawagoe

Yasuharu Oyama

Kazushige Sugamata

Yasuji Shibahata

Masayuki Kikuchi

Nobuyoshi Asanuma

Nobuo Sugitani

Hisao Asaumi

Yoshimitsu Akuta

Masaaki Kawano

Satoshi Andou

Hitoshi Iwai

Masaya Yamada

A vehicle has a rear wheel drive device for driving rear wheels independently of a front wheel drive device. A drive mode control unit performs at least one of a first switching operation for switching between a front-wheel-only-drive mode and a rear-wheel-only-drive mode, a second switching operation for switching between a composite drive mode and the rear-wheel-only-drive mode, and a third switching operation for switching between the composite drive mode and the front-wheel-only-drive mode. When the drive mode control unit performs any one of the first switching operation, the second switching operation, and the third switching operation, an assistive force controller of the steering apparatus changes a control process for controlling a steering assistive force.

Vehicle and steering apparatus

A vehicle in which a drive state can be favorably selected in a configuration that separately and independently drives front and rear wheels and a method for controlling the vehicle. In the vehicle and control method thereof, a drive state control device prohibits operation of a first switch between front wheel drive (FWD) and all wheel drive (AWD) and a second switch between rear wheel drive (RWD) and AWD when a lateral acceleration related value of the vehicle exceeds a first threshold value G. The first threshold value Gis set with a divergence reference value Gref as a reference. The Gref value is determined considering factors such as lateral acceleration, turning characteristics and the drive state of the vehicle.

Vehicle and method for controlling vehicle

In an electric power steering system () for use in a vehicle incorporated with a vehicle behavior control system (), a failure detecting unit () detects a failure of the electric power steering system according to the steering torque and actual electric current. A criterion for detecting a failure by the failure detecting unit is changed when the vehicle behavior control system is activated. Thereby, even when the vehicle behavior control system is activated and it causes a corrective current to be supplied to the electric motor, because the failure detection criterion is changed, the failure detecting unit is prevented from confusing the corrective current due to the operation of the vehicle behavior control system with an erroneous current caused by a failure of the electric power steering system. Therefore, an unnecessary interruption of the operation of the electric power steering system can be avoided, and the convenience of the electric power steering system can be enhanced.

Electric power steering system with failure detection

A steering system includes: an electric power steering device which includes a steering unit of front wheels having an electric motor for generating an auxiliary torque in accordance with at least a steering torque and for transmitting the auxiliary torque to the steering unit; toe angle changers for changing toe angles of rear wheels in accordance with at least a front wheel turning angle and a vehicle speed; and a steering controller for controlling the electric power steering device and the toe angle changer. The steering system further includes a toe angle changer anomaly detection unit and/or an electric power steering device anomaly detection unit, and when a toe angle changer abnormal state is detected, an auxiliary torque target value and/or a viscosity in the electric power steering device is controlled, and when an electric power steering device abnormal state is detected, the toe angle changer is controlled.

Steering system

A steering system includes a steering wheel, a steering angle sensor detecting a steering angle, a steering motor steering road-wheels, a reaction motor imparting a reaction force to the steering wheel, an ECU driving the steering motor with respect to a detected steering angle and a temperature detecting unit detecting temperatures of the steering motor, the reaction motor or a constituent member involved in the temperatures of the motors. When the temperature detected is larger than a predetermined value, the ECU performs such that a ratio of the rotating angle to the steering angle is made smaller than one that is to result when the temperature is equal to or smaller than the predetermined value, or a reaction force that is to be imparted to the steering wheel is made larger.

Steering system and method of control

In a steering control system for controlling torque steer in a vehicle equipped with an electric power steering device and a torque split arrangement for individually controlling traction and/or braking force of right and left wheels, a difference in traction and/or braking force between the right and left wheels which may be produced by the torque split arrangement may give rise to torque steer depending on the geometry of the wheel suspension system of the vehicle. The control unit for the electric power steering device additionally receives an additional signal for providing an additional steering torque which is required for canceling the torque steer. Thus, the torque steer can be eliminated both economically and reliably without requiring to modify the wheel suspension system.

Steering control system for controlling torque steer

In a steering system which produces a reactive steering assist torque which tends to cancel any unintended or undesired behavior of the vehicle, the control unit for the steering system is prevented from producing any reactive steering assist torque when the vehicle speed is zero so that no reactive steering assist torque may be produced to the discomfort of the vehicle even when the vehicle is being moved by external causes such as when being turned by a turntable or being transported by a car lift or a car carrier.

Reactive steering control system

In a steering system which produces a reactive steering assist torque which tends to cancel any unintended or undesired behavior of the vehicle, the relationship between the steering angle and the vehicle behavior such as the yaw rate and the lateral acceleration reverses in sense depending on the traveling direction of the vehicle. To prevent the control unit for the steering system from producing any reactive steering assist torque which could worsen the behavior of the vehicle when the vehicle is traveling rearward, the control unit either eliminates or reverses the sense of the reactive steering assist torque when the vehicle is traveling rearward.

In a vehicle steering control system, a manual steering input is assisted by a powered actuating steering torque which is given by K(.gamma.-t.sub.d .multidot.d .gamma./dt), where y is a detected yaw rate, K and t.sub.d are coefficients which depend on a vehicle speed, and d/dt denotes a time derivative. The detected yaw rate contributes to reducing the yaw rate of the vehicle. In particular, the coefficient t.sub.d is positive in value in a low speed range, and substantially linearly decreases with the vehicle speed, becoming negative at a certain intermediate vehicle speed. Thus, in a high speed range, when the vehicle is steered in one direction either by external disturbances or by a manual steering input, the detected yaw rate and the change rate of the yaw rate both contribute to the reduction of the yaw rate. However, in a low speed range, when the vehicle is steered in one direction, the detected yaw rate contributes to the reduction of the yaw rate but the change rate of the yaw rate contributes to the increase of the yaw rate. Thus, in a high speed range, the vehicle is made highly immune against external disturbances and the effort required for the manual steering of the vehicle is increased with the increase in the change rate of the yaw rate. Conversely, in a low speed range, the stability of the vehicle is of no concern, and the effort required for the manual steering of the vehicle is decreased with the increase in the change rate of the yaw rate.

Vehicle steering control system

According to the invention, there is provided is a vehicle steering system which can improve the resistance of a vehicle against external disturbances such as crosswind, and can prevent the operability of the steering system from being seriously affected by a failure in a part of the system related to the generation of steering reaction such as a lateral acceleration sensor, a yaw rate sensor or a reaction control unit. Because the assisting steering torque continues to be produced even when a failure has occurred in a part related to the generation of steering reaction. Therefore, a fail-safe feature can be obtained, and unnecessary loss of the operability of the steering system can be avoided. By reducing the assisting steering torque from the normal level, which is effective when the sensors are operating normally, at such a time, the driveability of the steering system similar to that under the normal condition can be ensured.

Vehicle steering system

In a vehicle steering control system, an actuating torque is applied to steerable wheels according to a steering torque applied to a steering wheel in a conventional manner, and an additional actuating torque is applied to the steering wheel by an electric motor according to lateral dynamic conditions of the vehicle so as to control the lateral stability of the vehicle even in the presence of external interferences such as crosswind. Such external interferences are detected as a lateral dynamic condition of the vehicle such as the yaw rate of the vehicle, and the steering control system produces a steering reaction which counteracts such a lateral dynamic condition by applying the additional actuating torque to the steerable wheels so that the vehicle may maintain a straight course in spite of such external interferences without requiring any intentional efforts by the vehicle operator. A torque steer arising from the drive force applied to power driven steerable wheels can be also controlled as one form of external disturbances. In particular, by amplifying the steering reaction torque when the drive force is great, it is possible to favorably control the influences of a torque steer under any operation conditions.

A motor vehicle steering system has a yaw rate sensor for detecting a yaw rate of a motor vehicle, and a lateral acceleration sensor for detecting a lateral acceleration of the motor vehicle. The detected yaw rate and lateral acceleration are processed according to predetermined functions to determine a control signal, which is applied to a motor to turn a steering wheel. Road wheels are correspondingly steered through a steering mechanism in a direction to suppress a disturbant motor vehicle behavior that is caused by the yaw rate and the lateral acceleration.

Motor vehicle steering system with automatic disturbance suppression

In a vehicle steering control system, an actuating torque is applied to steerable wheels according to a steering torque applied to a steering wheel in a conventional manner, and an additional actuating torque is applied to the steering wheel by an electric motor according to lateral dynamic conditions of the vehicle so as to control the lateral stability of the vehicle even in the presence of external interferences such as crosswind. Such external interferences are detected as a lateral dynamic condition of the vehicle such as the yaw rate of the vehicle, and the steering control system produces a steering reaction which counteracts such a lateral dynamic condition by applying the additional actuating torque to the steerable wheels so that the vehicle may maintain a straight course in spite of such external interferences without requiring any intentional efforts by the vehicle operator. In particular, by suppressing the additional actuating torque in an understeer condition, the handling of the vehicle can be improved.

In a vehicle steering control system, an actuating torque is applied to steerable wheels according to a steering torque applied to a steering wheel in a conventional manner, and an additional actuating torque is applied to the steering wheel by an electric motor according to lateral dynamic conditions of the vehicle so as to control the lateral stability of the vehicle even in the presence of external interferences such as crosswind. Such external interferences are detected as a lateral dynamic condition of the vehicle such as the yaw rate of the vehicle, and the steering control system produces a steering reaction which counteracts such a lateral dynamic condition by applying the additional actuating torque to the steerable wheels so that the vehicle may maintain a straight course in spite of such external interferences without requiring any intentional efforts by the vehicle operator. By representing the vehicle with a first-order delay transfer function in regards to its lateral dynamic response for each given steering input, the vehicle operator can handle the vehicle without encountering any substantial resistance even when the steering wheel is turned briskly or at high speed.

Growing community of inventors

Saitama-ken, Japan

Takashi Nishimori