Abstract:
An automatically driven motor vehicle automatically runs on a running path having path markers while detecting the path markers with a marker sensor. A present position of the motor vehicle on the running path is recognized, and a speed plan which governs a position and a speed of the motor vehicle on the running path is generated. A planned position to be reached by the motor vehicle after a predetermined time and a planned speed of the motor vehicle at the planned position are determined from the present position of the motor vehicle based on the speed plan. A predicted position to be reached by the motor vehicle after the predetermined time and a predicted speed of the motor vehicle at the planned position are determined from the present position, speed, and acceleration of the motor vehicle. A distance deviation between the predicted position and the predicted position and a speed deviation between the planned speed and the predicted speed are determined. Acceleration/deceleration correcting data for the motor vehicle are determined based on the distance deviation and the speed deviation. Acceleration/deceleration of the motor vehicle are controlled based on the acceleration/deceleration correcting data.
Abstract:
A steering system for a vehicle with a steerable front wheel (5) and a rear wheel (11) controlled to be steered in accordance with a travelling state representative quantity (.delta..sub.f, V, .alpha..sub.a), wherein the rear wheel is steered taking into account at least a ratio of a cornering power (Kr) thereof to a vertical load on the tire thereof, besides the travelling state representative quantity.
Abstract:
Disclosed is an actuator for steering the rear wheels in front and rear wheel steering device for vehicle in which the external forces, such as the self aligning torque of the rear wheels and irregularities of the road surface, which may be applied to the rear wheels are prevented from being transmitted to the actuator for controlling the steering angle of the rear wheels. Thereby, the steering angle of the rear wheels are determined solely by the control action of the front and rear wheel steering device and the motion of the vehicle is not affected by external forces. As a result, the vehicle motion is stabilized. When the force for steering the front wheels is transmitted to the rear wheels to steer them, elimination of the reaction from the road to the actuator prevents undesirable variation in the force required to steer the vehicle or the force required to hold a steering angle. Elimination of reaction to the actuator can be accomplished by worm gears, screw threads and so on in which the lead angle is smaller than the friction angle.
Abstract:
The front and rear wheel steering device of the present invention not only has a means for allowing the manual selection of a mathematical function which determines the steering angle ratio of the rear wheels relative to the front wheels from a plurality of mathematical functions but also has a means for limiting such a manual selection depending on the condition of the vehicle. Since manual selection of a mathematical function for the steering angle ratio may not be appropriate under certain vehicle conditions, the device of the present invention limits such a manual selection when the vehicle speed, the vehicle acceleration, the shift position of the transmission, the steering speed or the steering acceleration is greater than a certain value. Thereby, the convenience of the manual selection of the steering angle ratio is preserved yet any undesirable vehicle response from improper manual selection of the steering angle ratio is prevented.
Abstract:
A steering system for vehicles in which the steered angle ratio of a rear wheel to a front wheel is controllable in accordance with the vehicle speed. The steering system is provided with a manual switch device for selecting to set an arbitrary one of a plurality of predetermined steered angle ratios. The steering system may be further provided with a switch lock device for locking the switch state of the manual switch device. The switch lock device may be actuated when the vehicle speed is higher than a predetermined reference vehicle speed. Further, the switch lock device may be actuated when a reduction gear is shifted to a shift position having a relatively low reduction ratio. The switch lock device may also be actuated when the steered angle of the front wheel is larger than a predetermined value.
Abstract:
A steering system for vehicles including a signal providing mechanism (34) for providing an information signal (Su) in relation to the vehicle speed, in which the steered angle ratio of a rear wheel (20) to a front wheel (7) is controlled to be variable in accordance with the information signal.The signal providing mechanism comprises a sensor (34) adapted to detect the shift position of a speed change gear (33) of the vehicle.In the steering system, the steered angle ratio of the rear wheel (20) to the front wheel (7) may be controlled to be variable in accordance with the vehicle speed, wherein the vehicle speed is detected by a cooperative combination of a sensor (34) for detecting the shift position of a speed change gear (33) of the vehicle and a sensor (43) for detecting the number of revolutions per minute of an engine (42) of the vehicle.
Abstract:
A steering system for a vehicle including a front wheel and a rear wheel.The steering system comprises a steering wheel, a front wheel steering sub-system for steering the front wheel in accordance with the steering angle of the steering wheel, and a rear wheel steering sub-system for steering the rear wheel in accordance with the steering angle of the steering wheel. The rear wheel steering sub-system has a reaction mechanism for keeping substantially constant the steering torque necessary for turning the rear wheel.
Abstract:
A steering apparatus for a four-wheeled vehicle including a pair of pivotable knuckle arms connected to a pair of respective front wheels and actuatable through a steering gear by rotational movement of a steering wheel. One of the knuckle arms is pivotally connected to one end of a connector rod extending longitudinally of the vehicle, the other end of the connector rod being connected to a cam plate slidable in a housing. The cam plate has an inverted S-shaped cam groove or alternatively an S-shaped cam groove within which is slidably received a pin mounted on a tie rod pivotally connected between a pair of pivotable support arms supporting a pair of rear wheels, respectively. Due to the shape of the cam groove, the rear wheels are turned in the same direction as the front wheels when the steering wheel is rotated through a relatively small angle, and the rear and front wheels are turned in opposite directions when the steering wheel is rotated through a relatively large angle.
Abstract:
In a vehicle operation assist control system for assisting a vehicle operator to operate a vehicle, a distance to the obstacle and a width of the obstacle are detected by a radar or the like, and, when an obstacle is detected, the system determines an evasion path and accordingly modifies the map information available to the system. Therefore, the system, being aware of the situation, would not interfere with the vehicle operator taking an evasive action. The evasive path may be defined as a curvature which changes as a sinusoidal mathematical function of the position of the vehicle along the path. The control system may be based on a yaw rate control or a vehicle side slip angle control.
Abstract:
Provided are a method and system for computing a vehicle body slip angle in the vehicle movement control so as to allow the vehicle movement to be controlled with an adequate response and stability for practical purposes even without directly detecting or accurately estimating the frictional coefficient between the road surface and the tire. A tire slip angle is computed from a yaw rate, a vehicle speed, a vehicle body slip angle and a road wheel steering angle; a cornering force is computed from a dynamic model of the tire by taking into account at least the tire slip angle; and a hypothetical vehicle body slip angle is computed from the cornering force, the vehicle speed and the yaw rate; the tire slip angle being computed by feeding back the hypothetical vehicle body slip angle in a recursive manner.