An apparatus for controlling an MDPS system may include: a column torque sensor configured to sense column torque applied to a steering column of a vehicle; a vehicle velocity sensor configured to sense vehicle velocity of the vehicle; an MDPS basic logic unit configured to decide a first assist command current for driving an MDPS motor in a manual driving mode of a driver; an autonomous driving control unit configured to decide a second assist command current for driving the MDPS motor in an autonomous driving mode of the vehicle; and a mode switching control unit configured to decide a weight into which the driver's steering intention is reflected, and apply the decided weight to the first and second assist command currents to decide a final assist command current for driving the MDPS motor when the vehicle is switched from the autonomous driving mode to the manual driving mode.

A turning control system includes a controller. The controller is configured to perform a decrease process of decreasing a magnitude of an angle operation amount which is reflected in an operation process with respect to the magnitude of the angle operation amount calculated in an angle operation amount calculating process when a vehicle speed is equal to or lower than a prescribed speed and a magnitude of an input torque of a steering wheel is equal to or less than a prescribed value. The controller is configured to perform a correction process of correcting an input when the decrease process is performed such that a magnitude of the input decreases when an angle command value calculating process calculates an angle command value.

A turning control system includes a controller. The controller is configured to perform a decrease process of decreasing a magnitude of an angle operation amount which is reflected in an operation process with respect to the magnitude of the angle operation amount calculated in an angle operation amount calculating process when a vehicle speed is equal to or lower than a prescribed speed and a magnitude of an input torque of a steering wheel is equal to or less than a prescribed value. The controller is configured to perform a correction process of correcting an input when the decrease process is performed such that a magnitude of the input decreases when an angle command value calculating process calculates an angle command value.

A method for fine-tuning a variable-gear steering column according to a speed of the vehicle, the method includes: a step of characterizing a desired handling of the vehicle for a speed V1 and of characterizing a desired stability for a speed V2; a step of determining a value G1 of the gear ratio allowing obtaining the desired handling at the speed V1, and a value G2 of the gear ratio allowing obtaining the desired stability at the speed V2, a step of calculating a parameter p1 and a parameter p2 according to the speed V1, the speed V2, the value G1 and the value G2 so that the relationship between the gear ratio and the speed of the vehicle is defined by the equation G=p2+p1/V, when the speed is included between a first threshold and a second threshold.

A method is for controlling a wheel steering angle of at least one vehicle wheel of a vehicle, in particular of a motor vehicle. The vehicle has a steer-by-wire steering system including at least one wheel steering angle control element, which is provided at least for modifying the wheel steering angle of the vehicle wheel according to a steering demand. In at least one operating mode, in which the vehicle is at a standstill and a steering demand is received, the wheel steering angle of the vehicle wheel is at least substantially maintained at a constant value and a desired wheel steering angle for the vehicle wheel is determined in accordance with the steering demand. In at least one subsequent additional operating mode, in which the vehicle is moving, the wheel steering angle is adjusted to the desired wheel steering angle by the wheel steering angle control element.

A method for determining a gear ratio (VGR) for a power steering system of a vehicle, said power steering system comprising a steering wheel determining a steering wheel angle (A.sub.v) and a rack determining a rack position (X.sub.c), said rack position (X.sub.c) varying between a lower limit rack position and an upper limit rack position (X.sub.csup), the gear ratio (VGR) defining a ratio between the rack position (X.sub.c) and the steering wheel angle (A.sub.v), or conversely, characterized in that the method comprises a definition step in which the gear ratio (VGR) is defined as a function of a vehicle speed (V1, V2, V3) and of the steering wheel angle (A.sub.v) so that the upper limit rack position (X.sub.csup) corresponds to a single upper limit steering wheel angle (A.sub.vsup).

Provided is an electric power steering device including a phase compensation unit having a desirable phase compensation characteristic for each vehicle speed region, which suppresses deterioration in stability of a steering system in a case where the phase compensation characteristic is changed to a different phase compensation characteristic, in which the phase compensation unit includes: a plurality of phase compensation calculation units configured to execute phase compensation calculation based on each phase compensation characteristic; a phase compensation characteristic determination unit configured to determine a phase compensation characteristic based on a vehicle speed signal output from a vehicle speed sensor; and a selection unit configured to select a phase-compensated torque signal output by the phase compensation unit from phase compensation calculation results output by the plurality of phase compensation calculation units in consideration of an amount of change in phase compensation calculation result at a time of switching the phase compensation characteristic.

Provided is an electric power steering device including a phase compensation unit having a desirable phase compensation characteristic for each vehicle speed region, which suppresses deterioration in stability of a steering system in a case where the phase compensation characteristic is changed to a different phase compensation characteristic, in which the phase compensation unit includes: a plurality of phase compensation calculation units configured to execute phase compensation calculation based on each phase compensation characteristic; a phase compensation characteristic determination unit configured to determine a phase compensation characteristic based on a vehicle speed signal output from a vehicle speed sensor; and a selection unit configured to select a phase-compensated torque signal output by the phase compensation unit from phase compensation calculation results output by the plurality of phase compensation calculation units in consideration of an amount of change in phase compensation calculation result at a time of switching the phase compensation characteristic.

A steering control device includes a control circuit that controls a steering device. The control circuit is configured to execute an end-abutting relaxation control to correct a current command value such that decrease in an end interval angle is restricted, when the end interval angle is equal to or smaller than a predetermined angle, the end interval angle indicating the distance of an absolute steer angle from an end position correspondence angle. The control circuit is configured to perform a slewing intention determination of whether it is intended to perform the slewing travel of a vehicle during the execution of the end-abutting relaxation control. The control circuit is configured to perform a partial release control to reduce a correction amount of the current command value in the execution of the end-abutting relaxation control when it is determined that it is intended to perform the slewing travel of the vehicle.

A steering control device includes a control circuit that controls a steering device. The control circuit is configured to execute an end-abutting relaxation control to correct a current command value such that decrease in an end interval angle is restricted, when the end interval angle is equal to or smaller than a predetermined angle, the end interval angle indicating the distance of an absolute steer angle from an end position correspondence angle. The control circuit is configured to perform a slewing intention determination of whether it is intended to perform the slewing travel of a vehicle during the execution of the end-abutting relaxation control. The control circuit is configured to perform a partial release control to reduce a correction amount of the current command value in the execution of the end-abutting relaxation control when it is determined that it is intended to perform the slewing travel of the vehicle.