A rotation transmission device is provided which includes rollers disposed between the inner periphery of an outer ring and the outer periphery of an inner ring; an armature supported to axially move when an electromagnet is energized; and a ball ramp mechanism which converts the axial movement of the armature into the motion/movement of a roller cage from an engaged position to a disengaged position. This rotation transmission device further incudes an annular cover member made of aluminum, an O-ring and an oil seal.

A motor drive system is provided in a steer-by-wire system in which a steering mechanism and a turning mechanism of a vehicle are mechanically separated. The motor drive system includes a reaction force actuator and a turning actuator. The reaction force actuator functions as a motor configured to output a reaction force torque corresponding to a steering torque of a driver and a road surface reaction force. The turning actuator functions as a motor configured to output a turning torque for turning wheels. Each of the reaction force actuator and the turning actuator includes a plurality of control calculation units provided redundantly and each configured to perform a calculation related to a motor drive control, and a plurality of motor drive units provided redundantly and each configured to drive and output the torque based on a drive signal generated by a corresponding control calculation unit.

A steer-by-wire type vehicle includes actuators operated by electric power supplied from a power supply device. The actuators include a turning actuator for turning a wheel and a reaction actuator for applying a reaction torque to a steering wheel. The power supply device includes a main power supply and a backup power supply. A control device for the vehicle executes turning control that turns the wheel by controlling the turning actuator according to a steering operation of the steering wheel. When the electric power is supplied from the main power supply to the actuators, the control device executes reaction torque control that applies the reaction torque to the steering wheel by controlling the reaction actuator according to the steering operation. When the electric power is supplied from the backup power supply to the actuators, the control device executes power suppression processing that stops control of the reaction actuator.

The disclosure relates to a steering system for a motor vehicle, which is designed as a steer-by-wire steering system and comprises a rack, an electric drive for longitudinal displacement of the rack, a worm gear and a drive shaft which is in toothed engagement with the rack. The electric drive is connected to the drive shaft by the worm gear so as to transmit torque.

Control calculation units of a back system in each actuator operate by a collaborative drive mode in which a torque is output to a motor drive unit by using an information transmitted and received mutually by a communication between the systems in common. Cooperative control calculation units in a reaction force actuator and a turning actuator can operate in cooperation with each other based on the information transmitted and received mutually by a communication between actuators. A communication between adjacent systems and a communication between adjacent actuators are restored, when a focus control calculation unit is restored, after the focus control calculation unit is stopped during operation and at least one of the communication between adjacent systems or the communication between adjacent actuators is interrupted.

The present disclosure relates to a power assist control apparatus and a power assist control method. The power assist control apparatus according to the present disclosure comprises: a main motor driven at a first rotation speed; a sub-motor driven at a second rotation speed; and a controller which receives steering information from a steering wheel to calculate a target rotation speed value of an output shaft, and controls the main motor and the sub-motor such that the output shaft is rotated at the target rotation speed.

A method for operating a motor vehicle, wherein the motor vehicle has a steering system for steering at least one wheel of the motor vehicle by means of a drive. In doing so, it is provided that a time span is determined for at least one countermeasure limiting a hazard to a vehicle occupant upon an at least partial failure of the steering system, within which time span the countermeasure deploys an effect, and that a state variable (T) influencing the operating capacity of the steering system is determined and extrapolated over time and a point in time (t.sub.1) is calculated in which the state variable (T) exceeds a limit value (T.sub.1), wherein the countermeasure is introduced when the point in time (t.sub.1) is less than the time span in the future.

A number of variations may include a method including using at least one of brakes or propulsion energy to steer an autonomous or semi-autonomous vehicle if a primary, secondary or other redundant steering system for an autonomous or semi-autonomous vehicle has failed or is insufficiently unhealthy to perform a desired function, the method including determining if a primary, secondary or other redundant steering system of an autonomous or semi-autonomous vehicle has failed or is not sufficiently healthy to perform a desired function, and if so, converting a steer request into a desired yaw rate, curvature, curvature over time, radius, radius or time or yaw rate acceleration, calculating a brake pressure sufficient to produce the desired yaw rate, curvature, curvature over time, radius, radius or time or yaw rate acceleration, delivering brake pressures signals via a lateral control module to an actuator for at least one brake connected to a wheel of the vehicle so that the brake pressure causes the vehicle yaw at the desired yaw rate, curvature, curvature over time, radius, radius or time or yaw rate acceleration.

A controller for a vehicle is configured to execute a process that detects an anomaly of a steering device and a process that performs an automatic turning control that causes the vehicle to turn automatically along a traveling route. The controller is configured to perform the automatic turning control by controlling the steering device when an anomaly of the steering device is not detected. The controller is configured to, when an anomaly of the steering device is detected, calculate, as a predicted value, a load on the substitute device on an assumption that the automatic turning control is performed by activating the substitute device, and perform the automatic turning control by controlling the substitute device when an allowable range that is a set of values of a load allowable to the substitute device includes the predicted value.

A trailer reverse assist system includes a coupler angle detection sensor to detect a zero degree angle of the trailer relative to the vehicle. A drift controller receives signals from vehicle dynamics sensors. The drift controller is electrically connected with a trailer reverse assist module. When the vehicle is backing up the trailer on the intended straight line implied path and since the coupler angle sensor, detecting the zero degree angle, is not perfectly calibrated, based in the signals from the vehicle dynamics sensors, the drift controller 1) estimates a distance that the trailer has drifted from the straight line desired path and 2) in a closed-loop feedback manner, provides a drift correction signal to the trailer reverse assist module for modifying the value of the zero degree angle and thus cause adjustment of the steering system to realign the trailer towards the straight line implied path without manual steering intervention.