An electric multi-mode steer-by-wire system and a mode switching method thereof. The electric multi-mode steer-by-wire system includes a steering hand wheel unit including a steering hand wheel, a road-feeling motor, a reducer and an electromagnetic clutch, a steering execution unit including two steering electric motor mechanisms, a steering gear and two steering road wheels, an electronic control unit configured to control the steering hand wheel unit and the steering execution unit to achieve switching among two-side steering-road-wheel independent steer-by-wire mode, steering-trapezoidal steer-by-wire mode and electric power steering mode, and a mode selection and display unit. The electromagnetic clutch connected to the steering execution unit. The steering electric motor mechanisms drive the steering road wheels to steer independently through lead screw-nut pairs; or respectively form a hydraulic cylinder with the steering gear to jointly or independently drive the steering road wheels to steer with steering-trapezoidal manner.

A plurality of power supply circuits include a second power supply circuit for a CPU included in a control unit and a first power supply circuit for another circuit. An output voltage from the first power supply circuit is higher than an output voltage from the second power supply circuit. A range of input voltage is divided into three levels of voltage sub-ranges in accordance with a requirements specification. When the input voltage falls within a lower level voltage sub-range, both of an output function of the first power supply circuit and an output function of the second power supply circuit are stopped. When the input voltage falls within an intermediate level voltage sub-range, the output function of the first power supply circuit is stopped. When the input voltage falls within an upper level voltage sub-range, all circuits are controlled so as to operate.

Provided is a motor-driven power steering system including: a motor driver; and a controller, wherein the controller is configured to: receive a first rotation angle obtained by a steering wheel angle sensor according to steering and a second rotation angle obtained by a motor position sensor, when a steered position of the steering wheel is in an auxiliary steering limit section and a difference value between the first rotation angle and the second rotation angle is different from a predetermined reference value, change a rotation position of the steering wheel angle sensor and a rotation position of the motor position sensor to an initial original position, when changed to the initial original position, receive the first rotation angle and the second rotation angle again, and control the motor driver to perform auxiliary steering based on the first rotation angle and the second rotation angle received again.

A current sensor state determination device determines that an abnormality is caused in a current sensor when a sum of phase currents based on current detection values from each of the current sensors in three phases is greater than a first determination value, and determines that no abnormality is caused in the current sensor when the sum of phase currents is equal to or less than the first determination value. The state determination device determines that the current sensor is normal when it is determined that (i) no abnormality is caused in a preset electric angle range equal to or less than one electric-angle cycle of the rotating electric machine and (ii) a value of an electric current flowing in the rotating electric machine in a rotating coordinates system calculated based on the current detection value is equal to or greater than a second determination value.

A turning system includes a steering wheel, a turning actuator that has an electric motor incorporated thereinto and turns turning wheels, and a control device. The control device is configured to perform: a steering operation amount calculating process of calculating a steering operation amount; an angle command value calculating process of calculating an angle command value; an angle operation amount calculating process of calculating an angle operation amount; an operation process of operating a drive circuit of the electric motor; and a correction process of correcting a parameter upstream from the angle operation amount calculating process such that a drag force resisting an operation of the steering wheel for increasing magnitude of the turning angle is applied when the magnitude of the turning angle is equal to or greater than a turning angle threshold value.

A motor electric control unit (ECU) for an electromechanical power steering mechanism, which controls current through an electric assist motor in response to sensed vehicle signals, wherein the ECU comprises an application specific integrated circuit (ASIC) design, that implements safety and platform features in hardware.

A method of controlling operation of an electric machine includes: determining a voltage-based torque limit based on a voltage constraint of a direct current (DC) bus supplying power to an inverter for powering the electric machine; determining a motor current-based torque limit based on a motor current limit; determining a final torque limit based on the voltage-based torque limit and the motor current-based torque limit; determining a limited command torque based on a torque command and the final torque limit; determining an initial current command corresponding to the inverter satisfying a regenerative current limit of the DC bus; and calculating a final current command based on, at least, the limited command torque and the initial current command. The method includes the final current command exceeding the initial current command to cause the electric machine to produce a torque corresponding to the limited torque command.

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.

A steering control device is configured to control a motor, the motor being a generation source of a driving force that is given to a steering mechanism of a vehicle. The steering control device includes a controller configured to compute a controlled variable depending on a steering state, the controlled variable being used in the control of the motor. The controller is configured to alter a control parameter for the controller, based on a command that is generated by a host control device depending on a purpose of an intervention in a steering control, the host control device being mounted on the vehicle.

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.