Abstract: A vehicular steering apparatus according to the invention includes a steering angle correction mechanism, a steering power assist mechanism, and a controller. The steering angle correction mechanism works to provide a correction steering angle to a steerable road wheel of a vehicle. The steering power assist mechanism is configured to provide the steerable road wheel of the vehicle with a base assist power and a correction assist power in a first operation mode and the base assist power and a limited correction assist power in a second operation mode. The controller works to control the steering angle correction mechanism to provide the correction steering angle to the steerable road wheel. The controller also works to control the steering power assist mechanism to operate in the first operation mode if the absolute value of the correction steering angle is greater than a predetermined value and in the second operation mode otherwise.

Abstract: A fault detection unit detects a fault occurred in a detecting device which detects a rotational angle of a rotor with respect to a stator from sine and cosine wave signals having amplitudes modulated in a sinusoidal wave shape in a cycle of rotation of the rotor. The unit produces a judging value from the signals, judges occurrence of a fault from the value placed out of a normal range, and judges the device to be in a tentative fault state when the judgment is continued. After this judgment, when the rotational angle is changed over its entire range while the value is placed within the normal range, the unit judges the device to have returned to a normal state. In contrast, when the judgment is still continued, the unit judges the device to be in a determinate fault state and decides the occurrence of the fault.

Abstract: A vehicle steering system for steering vehicle wheels includes a steering wheel, a steering power assisting unit for providing assisting power when the steering wheel is steered, a transfer ratio control mechanism for controlling the ratio of a steering angle of the steering wheel to a steered angle of the vehicle wheels according to a vehicle condition; a steering torque sensor, a motor control circuit for controlling the driving motor so as to cancel the steering torque applied to the steering wheel when the steering torque sensor detects a steering torque applied to the steering wheel until the transfer ratio control mechanism starts operation. The transfer ratio control mechanism includes a transfer ratio changing mechanism and a driving motor for driving the transfer ratio changing mechanism.

Abstract: An inverter circuit includes a bridge circuit constituted of a plurality of pairs of a high-side switching element and a low-side switching element, a command signal processing section, a pulse generating section for generating pulse signals to control the inverter bridge circuit according to the command signal to have a dead time to prevent short circuiting of the dc power source and a command signal compensation section. The compensation section modifies the command signal according to a current voltage level of the dc power source to control the dead zone, thereby preventing deformation of ac output power of the bridge circuit.

Abstract: A fault detection unit detects a fault occurred in a detecting device which detects a rotational angle of a rotor with respect to a stator from sine and cosine wave signals having amplitudes modulated in a sinusoidal wave shape in a cycle of rotation of the rotor. The unit produces a judging value from the signals, judges occurrence of a fault from the value placed out of a normal range, and judges the device to be in a tentative fault state when the judgment is continued. After this judgment, when the rotational angle is changed over its entire range while the value is placed within the normal range, the unit judges the device to have returned to a normal state. In contrast, when the judgment is still continued, the unit judges the device to be in a determinate fault state and decides the occurrence of the fault.

Abstract: A vehicle steering system for steering vehicle wheels includes a steering wheel, a steering power assisting unit for providing assisting power when the steering wheel is steered, a transfer ratio control mechanism for controlling the ratio of a steering angle of the steering wheel to a steered angle of the vehicle wheels according to a vehicle condition; a steering torque sensor, a motor control circuit for controlling the driving motor so as to cancel the steering torque applied to the steering wheel when the steering torque sensor detects a steering torque applied to the steering wheel until the transfer ratio control mechanism starts operation. The transfer ratio control mechanism includes a transfer ratio changing mechanism and a driving motor for driving the transfer ratio changing mechanism.

Abstract: A motor controller including an inverter including plural switching elements that are subjected to PWM control to generate sine waves of plural phases, a motor including a stator coil supplied with the sine waves thus generated so that rotational magnetic field is generated in the stator coil, and a rotor that is rotationally driven by the action of the rotational magnetic field generated by the stator coil, a storage unit for detecting the sine waves of the respective phases generated in the inverter and storing a correction amount for each phase that is calculated on the basis of the detection result so that the sine waves of the respective phases are coincident with one another and a correcting unit for correcting a PWM signal for carrying out the PWM control on the switching elements on the basis of the correction amount thus calculated.

Abstract: A variable transmission ratio steering apparatus for a vehicle is configured with an input shaft coupled to a steering wheel of the vehicle, a sensor for sensing a rotation angle of the input shaft, an output shaft operatively linked to steerable road wheels of the vehicle, an actuator having an electric motor which is configured to vary a transmission ratio between a rotation angle of the output shaft and the rotation angle of the input shaft, and a controller. More specifically, the controller includes a desired rotation angle calculation unit, a difference calculation unit, and a difference limitation unit, whereby a rotation angle of a rotor of the electric motor is limited. With such a configuration, a rotation speed of the rotor of the electric motor can be limited by limiting the rotation angle of the rotor, and consequently, audible operation noises arising from the electric motor can be minimized.

Abstract: An inverter circuit includes a bridge circuit constituted of a plurality of pairs of a high-side switching element and a low-side switching element, a command signal processing section, a pulse generating section for generating pulse signals to control the inverter bridge circuit according to the command signal to have a dead time to prevent short circuiting of the dc power source and a command signal compensation section. The compensation section modifies the command signal according to a current voltage level of the dc power source to control the dead zone, thereby preventing deformation of ac output power of the bridge circuit.

Abstract: A motor controller including an inverter including plural switching elements that are subjected to PWM control to generate sine waves of plural phases, a motor including a stator coil supplied with the sine waves thus generated so that rotational magnetic field is generated in the stator coil, and a rotor that is rotationally driven by the action of the rotational magnetic field generated by the stator coil, a storage unit for detecting the sine waves of the respective phases generated in the inverter and storing a correction amount for each phase that is calculated on the basis of the detection result so that the sine waves of the respective phases are coincident with one another and a correcting unit for correcting a PWM signal for carrying out the PWM control on the switching elements on the basis of the correction amount thus calculated.

Abstract: A vehicular steering apparatus according to the invention includes a steering angle correction mechanism, a steering power assist mechanism, and a controller. The steering angle correction mechanism works to provide a correction steering angle to a steerable road wheel of a vehicle. The steering power assist mechanism is configured to provide the steerable road wheel of the vehicle with a base assist power and a correction assist power in a first operation mode and the base assist power and a limited correction assist power in a second operation mode. The controller works to control the steering angle correction mechanism to provide the correction steering angle to the steerable road wheel. The controller also works to control the steering power assist mechanism to operate in the first operation mode if the absolute value of the correction steering angle is greater than a predetermined value and in the second operation mode otherwise.

Abstract: A transmission ratio of a rotational angle of an output shaft to a rotational angle of an input shaft is adjustable by a transmission ratio changing mechanism when a coupling member is in a unlocked position. A resilient member urges the coupling member toward the locked position. A solenoid holds the coupling member at the unlocked position against a resilient force of the resilient member. A solenoid drive control apparatus applies a drive voltage to the solenoid to hold the coupling member positioned at the unlocked position and reduces the drive voltage through a voltage attenuation process before the coupling member finally reaches the locked position. During the voltage attenuation process, the solenoid produces an electromagnetic force yielding to the resilient force of the resilient member and decreases a shifting speed of the coupling member on the way to the locked position.

Abstract: A transmission ratio of a rotational angle of an output shaft to a rotational angle of an input shaft is adjustable by a transmission ratio changing mechanism when a coupling member is in a unlocked position. A resilient member urges the coupling member toward the locked position. A solenoid holds the coupling member at the unlocked position against a resilient force of the resilient member. A solenoid drive control apparatus applies a drive voltage to the solenoid to hold the coupling member positioned at the unlocked position and reduces the drive voltage through a voltage attenuation process before the coupling member finally reaches the locked position. During the voltage attenuation process, the solenoid produces an electromagnetic force yielding to the resilient force of the resilient member and decreases a shifting speed of the coupling member on the way to the locked position.

Abstract: A variable transmission ratio steering apparatus for a vehicle is configured with an input shaft coupled to a steering wheel of the vehicle, a sensor for sensing a rotation angle of the input shaft, an output shaft operatively linked to steerable road wheels of the vehicle, an actuator having an electric motor which is configured to vary a transmission ratio between a rotation angle of the output shaft and the rotation angle of the input shaft, and a controller. More specifically, the controller includes a desired rotation angle calculation unit, a difference calculation unit, and a difference limitation unit, whereby a rotation angle of a rotor of the electric motor is limited. With such a configuration, a rotation speed of the rotor of the electric motor can be limited by limiting the rotation angle of the rotor, and consequently, audible operation noises arising from the electric motor can be minimized.