Abstract: An electric power steering apparatus includes a motor for applying assist torque to a vehicle steering mechanism and a controller, which controls driving of the motor to cause the assist torque to follow an assist command value. The controller calculates a basic assist command value based on steering torque applied to the steering mechanism and corrects the basic assist command value using a correction value, thereby setting the assist command value. If the steering torque has an absolute value greater than a threshold value when the vehicle is in a straight-line traveling state, the controller sets the correction value such that the absolute value of the steering torque is reduced. If the steering torque has an absolute value less than the threshold value when the vehicle is in a straight-line traveling state, the controller sets the correction value such that the absolute value of the assist command value is reduced.

Abstract: When an engine is to be restarted, a power-steering mechanism is reactivated once a battery voltage has reached at least a predetermined voltage at which the power-steering mechanism normally operates after the resistance of a power supply circuit is switched by the circuit switching device, after startup of the engine has been initiated.

Abstract: When an engine is to be restarted, a power-steering mechanism is reactivated once a battery voltage has reached at least a predetermined voltage at which the power-steering mechanism normally operates after the resistance of a power supply circuit is switched by the circuit switching device, after startup of the engine has been initiated.

Abstract: An electric power steering apparatus includes a motor for applying assist torque to a vehicle steering mechanism and a controller, which controls driving of the motor to cause the assist torque to follow an assist command value. The controller calculates a basic assist command value based on steering torque applied to the steering mechanism and corrects the basic assist command value using a correction value, thereby setting the assist command value. If the steering torque has an absolute value greater than a threshold value when the vehicle is in a straight-line traveling state, the controller sets the correction value such that the absolute value of the steering torque is reduced. If the steering torque has an absolute value less than the threshold value when the vehicle is in a straight-line traveling state, the controller sets the correction value such that the absolute value of the assist command value is reduced.

Abstract: An electric power steering apparatus is provided that has a controller by which no current flows in one phase among current paths of three phases for supplying electric power from a motor driving circuit to a three-phase brushless motor and currents that have an identical absolute value and that have different signs flow in the other two phases. Thus, the status at one energization angle on the driving current waveform of the three-phase brushless motor can be given continuously and relatively-high currents can simultaneously flow in opposite directions in the contacts inserted to the two phases. By flowing of such high current in the contacts, a secure conduction check can be performed and foreign matters on the surface of the contact can be fused or thermally destroyed.

Abstract: In an electric power steering apparatus including a capacitor for smoothing out the voltage of a battery and a relay including a relay contact disposed at a place upstream of the capacitor, a path is provided for directly conducting a terminal voltage of the capacitor from a downstream side of the relay contact to a system power supply that generates a source voltage for a control system including a controller and the like, so that the system power supply and the control system that is supplied therefrom with electric power for control purpose are utilized as a discharge circuit. Thus is obtained a simplified configuration of circuit responsible for discharging the capacitor.

Abstract: In an electric power steering apparatus including capacitor for smoothing out the voltage of battery and relay including a relay contact disposed at a place upstream of the capacitor, a path is provided for directly conducting a terminal voltage of the capacitor from a downstream side of the relay contact to a system power supply supply that generates a source voltage for a control system including controller and the like, so that the system power supply and the control system that is supplied therefrom with electric power for control purpose are utilized as a discharge circuit. Thus is obtained a simplified configuration of circuit responsible for discharging the capacitor.

Abstract: An electric power steering apparatus is provided that has a controller by which no current flows in one phase among current paths of three phases for supplying electric power from a motor driving circuit to a three-phase brushless motor and currents that have an identical absolute value and that have different signs flow in the other two phases. Thus, the status at one energization angle on the driving current waveform of the three-phase brushless motor can be given continuously and relatively-high currents can simultaneously flow in opposite directions in the contacts inserted to the two phases. By flowing of such high current in the contacts, a secure conduction check can be performed and foreign matters on the surface of the contact can be fused or thermally destroyed.