Honda Giken Kogyo Kabushiki Kaisha

Honda Kigen Kogyo Kabushiki Kaisha

501 Honda Giken Kogyo Kabushiki Kaisha

Yutaka Nishi

Takashi Nishimori

Yorihisa Yamamoto

Hiroyuki Tokunaga

Hiroyuki Kawagoe

Hideki Machino

Yasuharu Oyama

Kazushige Sugamata

Shoichi Sano

Yoshimi Furukawa

Yasuji Shibahata

Shuji Shiraishi

Nobuyoshi Asanuma

Osamu Yamamoto

Takashi Nishihara

Mitsuya Serizawa

Nobuharu Kuriki

Akihiko Takei

Hidenori Ishihama

Yuichi Hashimoto

Akihiko Ohtsu

Yasuaki Ohno

Toyotaka Torii

Takuya Sakai

A cockpit is supported by a motion base in a state of being capable of making swinging movement. A host computer calculate vehicle motion information in accordance with operation of various operation equipments performed by a driver accommodated in the cockpit. A simulation image is formed, the cockpit is controlled for swinging movement, and various meters or the like in the cockpit are controlled on the basis of an obtained result of the calculation. Thus, the drive simulation is carried out in a state approximate to that of a real vehicle.

Drive simulation apparatus

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.

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 appropriate selection of the gain of the system for generating the additional actuating torque, this advantage can be gained without causing any excessive reaction when the vehicle is undergoing a normal turning maneuver.

Provided is a vehicle steering system which can substantially stabilize the lateral dynamic behavior of a vehicle with a simple control logic over the entire range of the vehicle speed. A steering torque proportional to a yaw rate and/or a lateral acceleration of the vehicle is applied to the steerable wheels to counteract a lateral deviation of the vehicle. To avoid the oscillatory or overshooting behavior of the control system, a damping torque is applied to the steering wheel. Thus, the counteracting steering torque is given as a mathematical function including a sum of a first term consisting of a product of a yaw rate and/or the lateral acceleration of the vehicle and a first coefficient, and a second term consisting of a product of an angular speed of the steering wheel and a second coefficient. In particular, the first coefficient and second coefficient are variable in a mutually proportional relationship so that the optimum selection of the first and second conditions can be done without any complication.

In a powered vehicle steering system which produces a steering reaction for controlling the lateral movement of the vehicle, the steering reaction including a yaw rate reaction component and a steering wheel damping component, when the vehicle operator is firmly holding the steering wheel or actually turning the steering wheel, the damping component is reduced so that the effort required for turning the steering wheel may be reduced, and the vehicle operator may turn the steering wheel without any substantial effort. Conversely, if the vehicle operator is not firmly holding the steering wheel, and the steering wheel is allowed to move freely, the damping component is increased so that the lateral movement of the vehicle may be stabilized even when the vehicle is subjected to disturbances such as crosswind. Thus, the stability of the lateral movement of the vehicle and the responsiveness of the vehicle steering system can be ensured at the same time.

A steering system for a motor vehicle having power steering means including an actuator for turning steerable road wheels of the motor vehicle includes a control mechanism for eliminating a deviation between a desired direction of travel of the motor vehicle and an actual direction of travel of the motor vehicle, based on an output signal from a direction indicating mechanism which indicates the desired direction and an output signal from a direction detecting mechanism which detects the actual direction. The control mechanism determines a target turning angle for the steerable road wheels dependent on the deviation between the desired direction and the actual direction, and controls the power steering mechanism to turn the steerable road wheels up to the target turning angle.

Growing community of inventors

Saitama-ken, Japan

Yutaka Nishi