A steer-by-wire steering system includes: a steering device including a steering motor powered by a main power source and/or a backup power source; and a controller configured to control the steering device based on a steering request. When the backup power source is normal, the controller executes an abnormal-situation control based on electric power supplied to the steering motor by the main power source and/or the backup power source when the controller determines that the voltage of the main power source is less than a first threshold. When the backup power source is abnormal, the controller executes the abnormal-situation control based on electric power supplied to the steering motor by the main power source when the controller determines that the voltage of the main power source is less than a second threshold that is greater than the first threshold.

A controller for a steering device includes an electronic control unit configured to control the steering device. The electronic control unit is configured to acquire an action force and to calculate a basic reaction force based on the acquired action force. The action force includes at least two of axial forces of a plurality of types and a tire force. The axial forces of a plurality of types are applied to a turning shaft that is connected to turning wheels. The tire force is applied to the turning wheels. The electronic control unit is configured to, when one predetermined force of the acquired action force is abnormal, calculate the basic reaction force such that a contribution proportion of the predetermined force to the basic reaction force is lower than a contribution proportion when the predetermined force is not abnormal.

An apparatus for driving a motor of an MDPS may include: first to fourth driving power supply units configured to supply driving power to a driving motor; first to fourth inverters configured to switch the driving power supplied from the first to fourth driving power supply units, and supply the switched driving motor to the driving motor, in order to drive the driving motor; first to fourth driving units configured to drive the first to fourth inverters, respectively; a first control unit configured to operate the driving motor by switching the first and second inverters through the first and second driving units; a second control unit configured to operate the driving motor by switching the third and fourth inverters through the third and fourth driving units.

A steering control device is configured to control steering via a steering actuator of a vehicle. The steering control device includes a condition determination unit and a steering maintenance unit. The condition determination unit is configured to determine whether a maintenance condition required to keep a steering angle at a stop control angle is satisfied, the steering angle being given by the steering actuator to a tire of the vehicle, the stop control angle being the steering angle which is to be given at a stop position where the vehicle stops traveling. The steering maintenance unit is configured to keep the steering angle at the stop control angle in a pre-stop traveling section in which the vehicle travels until the vehicle arrives at the stop position after the maintenance condition is satisfied.

A steering system to steer wheels by a movement of a steering shaft, including: the steering shaft; an electric motor; a converter configured to convert a rotational motion of the motor into the movement of the steering shaft; a motor rotation angle obtainer configured to obtain a motor rotation angle from a zero point position; a movement-amount-related-amount obtainer configured to obtain a movement-amount-related amount that is a movement amount of the steering shaft from a neutral position or a physical amount in a one-to-one correspondence with the movement amount; and a controller including a malfunction detector configured to detect a presence or absence of a malfunction of the converter in a mode that differs depending on a temperature state of the steering system, based on the motor rotation angle from the zero point position obtained by the motor rotation angle obtainer and the movement-amount-related amount obtained by the movement-amount-related-amount obtainer.

An automatic steering system comprises a controller. The controller executes target steering angle calculation processing. The controller further calculates a learning value of lateral acceleration. The learning value is calculated based on an error of a detected value of the lateral acceleration by an acceleration sensor and an estimation value of the lateral acceleration calculated using driving speed and yaw rate. In the target steering angle calculation processing, it is judged whether the acceleration sensor is normal. If it is judged that the acceleration sensor is normal, a target steering angle is calculated by using the detected value. Otherwise, the lateral acceleration used to calculate the target steering angle is switched from the detected value to a backup value of the lateral acceleration. The backup value is calculated using the estimation value and the learning value calculated before a timing at which the acceleration sensor is judged to be abnormal.

A heater-integrated fuse is provided at a neutral point of a stator coil, and when a short-circuit failure of an inverter is detected, a fuse part of the heater-integrated fuse is cut by heating.

A steering control device includes a controller including a drive circuit that performs action for supplying, to a motor, electric power supplied by being connected to at least one of a first and a second power supply. When a connection state of the drive circuit is a state in which electric power is supplied from the first power supply, the connection state is switched by a power supply device to transition to a second state in which electric power is supplied from the second power supply when an abnormality of the first power supply is detected. Moreover, the controller starts an output limiting process of limiting torque outputtable by the motor as compared with before the abnormality of the first power supply is detected, after the abnormality is detected and before switching of the connection state is completed.

A control device includes control circuits of a plurality of systems. When a transition condition is established, the control circuits of the systems make transition of a driving mode from a first driving mode to a second driving mode, and when a return condition is established in a state in which the driving mode has transitioned to the second driving mode, the control circuits of the systems make transition of the driving mode from the second driving mode to the first driving mode while gradually changing the current command values of the control circuits’ own systems toward the current command values before the adjustment.

Provided is an electric power steering device including: a front-wheel steering mechanism, which is provided to front wheels of a vehicle, and includes a front-wheel steering motor as a drive source; and a rear-wheel steering mechanism, which is provided to rear wheels of the vehicle, and includes a rear-wheel steering motor as a drive source, wherein the rear-wheel steering motor is configured to be a double-inverter three-phase duplex motor, the double-inverter three-phase duplex motor including two three-phase windings and two inverters each configured to individually drive one of the two three-phase windings. Therefore, the electric power steering device is capable of, even when a failure has occurred in the steering motor of the rear-wheel steering mechanism, maintaining a function of the rear-wheel steering mechanism to secure behavior stability of the vehicle.