Nsk Corporation

Sakae Nejo

Tomonori Sato

Toru Sakaguchi

Sumio Sugita

Takeshi Hara

Nobuhiro Mitsuishi

Hideaki Okazaki

Kenji Mori

Shuji Endo

Hideyuki Kobayashi

Yuho Aoki

Yong Wei

Lilit Kovudhikulrungsri

To provide a vehicle steering control device capable of suppressing influence of a torque generated during driving support by an EPS device on steering of a steering wheel performed by a driver. The vehicle steering control device includes an EPS controller (first controller) that controls a speed reduction mechanism and a differential mechanism controller (second controller) that controls a differential mechanism. In addition, the vehicle steering control device has a first steering assist mode of assisting driver's steering and a second steering assist mode of performing steering independently from the driver's steering. In the second steering assist mode, the second controller controls the differential mechanism so as to cancel a torque applied to a rack-and-pinion side of the differential mechanism from the speed reduction mechanism controlled by the first controller.

Vehicle steering control device

To provide a vehicle steering control device capable of alleviating discomfort caused by mismatch between a steering angle of a steering wheel and a steered angle of a drive wheel generated by automatic steering using an EPS device. The vehicle steering control device has a first steering assist mode of assisting driver's steering and a second steering assist mode of performing steering independently from the driver's steering. A second controller, performs phase shift suppression control to suppress a relative shift of a phase of a differential mechanism on a steering wheel side with respect to a reference phase on the steering wheel side of the differential mechanism corresponding to a phase on a rack-and-pinion side of the differential mechanism in the first steering assist mode.

An electric power steering apparatus that has a torque sensor which detects a steering torque, and a motor control apparatus to control the motor which applies an assist torque, by which steering is assisted, to a steering system of a vehicle, including: a function that switches a control system of the motor between an angle control system to control an angle corresponding to an angle control command value of an automatic steering mode and a torque control system to control a torque corresponding to a torque control command value of a manual steering mode in accordance with a predetermined switching trigger, wherein the steering apparatus variably sets a gradual-changing time corresponding to a command value difference between the angle control command value and the torque control command value when switching from the angle control system to the torque control system by using a gradual-changing.

Electric power steering apparatus

An electric power steering apparatus including a steering angle detection part that detects a steering angle of a steering wheel and outputs a steering angle signal, a steering control unit that controls a motor to give an assist torque to the steering wheel, an abnormality detection part that determines an abnormality of the steering angle detection part, and a motor angle detection part that detects a rotational angle of the motor. The steering control unit calculates a steering angle information based on at least the steering angle signal, and includes a signal storage part that stores the steering angle information. The steering control unit runs the motor continuously when the abnormality detection part detects the abnormality of the steering angle detection part until a vehicle stops or until the abnormality detection part determines that the steering angle signal returns to a normal state from the occurrence of the abnormality.

Control apparatus for electric power steering

An electric power steering device changes the discontinuous non-linear characteristics in the duty ratio of the PWM signal versus motor current generated during steering wheel handle return into linear characteristics to suppress noise and provides a smooth and natural feeling steering. The electric control circuit () provided a current reference value calculator (A) to calculate I, a current controller (B) to obtain V, a compensation adder () to obtain a duty D, and a current discontinuity compensator () in order to obtain a duty D. A motor drive circuit () including an H bridge circuit whose upper stage FET () is driven by the duty D, and whose lower stage FED () paired with the upper stage FET (), is driven by the duty Dto allow forming a continuous linear characteristic in the duty ratio of the PWM signal versus the motor current.

Electric power steering device

The present invention provides an excellent electric power steering apparatus in which torque ripple caused by a quantization error of a current control system generated in case of slow steering state and steering holding state, namely, vibration and noise on a steering wheel can be suppressed. A current controller in which a steady state gain of feedback control is a finite value is used so as to be capable of suppressing the vibration and noise. Further, according to the present invention, a smoothing filter is included in a current control system so that the quantization error is smoothed so that the torque ripple is suppressed.

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Gunma, Japan

Sakae Nejo