Abstract: There is provided a vehicle steering system which includes an electric motor for imparting a steering force to a steering mechanism of a vehicle and an automatic parking controller for executing an automatic parking control by controlling the electric motor, wherein the automatic parking controller controls an energizing voltage of the electric motor by imparting a square wave to the electric motor and increasing/decreasing a neutral point voltage of a winding of the electric motor.

Abstract: A brake application speed is compared with a speed threshold value so as to judge whether or not a braking operation being performed is an emergency braking operation. If not the emergency braking operation, an automatic parking mode is held. When the emergency braking operation is in effect, control information related to a state of an automatic parking control then is stored in a control information storage section, and the automatic parking control is cancelled. Thereafter, when a steering operation or a gearshift operation is performed before a cancellation of application of the brake is detected, the process is ended, and the control mode is held in an assist mode. When the application of the brake is cancelled with neither the steering operation nor the gearshift operation performed, the control information is read in so as to resume the automatic parking control.

Abstract: An automatic parking control is cancelled when a motor current has not yet reached a maximum current value Imax with a steering angle deviation exceeding a deviation threshold value. In addition, the automatic parking control is cancelled when a steering speed has not yet reached a maximum steering speed with a state where the motor current has reached and remains at the maximum steering speed continuing over a first time period. On the other hand, when a state where the steering speed has reached and remains at the maximum steering speed continues over a second time period, it is determined that there occurs an output shortage of a steering actuator, an automatic parking condition is recalculated, so as to allow the automatic parking continue to continue.

Abstract: In a steering-without-driving state, a larger current limit value, drive limit time and steering angle deviation threshold value are set than when a low-speed driving state occurs. An automatic parking mode is held until a time period over which a state where a motor current value of an electric motor which drives a steering mechanism is equal to the current limit value reaches the drive limit time. Even though the state where the motor current value is equal to the current limit value has continued over the drive limit time, the automatic parking mode is held during the steering angle deviation not exceeding the steering angle deviation threshold value. When the state where the motor current value is equal to the current limit value has continued over the drive limit time Ta and that the steering angle deviation exceeds the threshold value, the automatic parking control is cancelled.

Abstract: A vehicle steering system includes: a steering actuator that imparts a steering force to a steering mechanism of a vehicle; an automatic steering controller that performs an automatic steering control by controlling the steering actuator; a driving state detector that detects a driving state of the vehicle during the automatic steering control; a threshold value setting unit that variably sets a threshold value for permitting an intervention in the automatic steering control; and an automatic steering intervention unit that intervenes in the automatic steering control based on a threshold value set by the threshold value setting unit.

Abstract: In an automatic parking mode, a target path is obtained, and a vehicle is automatically controlled to follow the target path. When a driver intervenes steering of the vehicle, an anticipated course to be taken by the vehicle to follow after the intervention to the steering is calculated as a revised path. When the vehicle follows the revised path, if the vehicle is expected to be brought into contact with an obstacle, firstly, an alarm is raised. When an avoidance operation is performed after the alarm, an anticipated course to be taken by the vehicle to follow after the avoidance operation is re-calculated as a revised path. If no avoidance operation is performed or if the vehicle is expected to be brought into contact with the obstacle even when the vehicle follows the revised path, forced brakes are applied to the vehicle, and the automatic parking control is halted.

Abstract: A vehicle steering system includes: a control member that is manipulated by a driver for controlling a direction of a vehicle; a steering mechanism that turns steered road wheels in response to manipulation of the control member; an automatic driving mode setting unit that enables an automatic driving control for an automatic driving mode; a plurality of vehicle sensors for detecting various kinds of information which represent behaviors of the vehicle; an output gain switch that switches an output gain for a predetermined vehicle sensor of the plurality of vehicle sensors so as to output an appropriate output for the automatic driving mode in response to setting of the automatic driving mode by the automatic driving mode setting unit; and an automatic steering controller that automatically controls the steering mechanism while referring to outputs of the plurality of vehicle sensors in the automatic driving mode.