CONTROL APPARATUS OF ELECTRIC POWER STEERING APPARATUS

• US 20070273317A1
• Filed: 05/24/2007
• Published: 11/29/2007
• Est. Priority Date: 05/25/2006
• Status: Abandoned Application

• Current Assignee: NSK Limited
• Original Assignee: NSK Limited
• Inventors: HARA, Takeshi, AOKI, Yuho, ENDO, Shuji
• Application Number:
  US11/752,949
• Publication Number:
  US 20070273317A1
• Time in Patent Office: Days
• US Class Current: 318/432
• CPC Class Codes: B62D 5/0466 for returning the steering wheel to neutral position

Abstract

In a control apparatus of an electric power steering apparatus constructed so as to calculate a current command value of a motor for applying steering assist force to a steering mechanism based on steering torque and a vehicle speed and drive and control the motor based on the current command value, there are provided an SAT detection part for detecting or estimating an SAT detection value, a standard SAT calculation part for calculating a standard SAT value based on a steering angle and the vehicle speed, and a correction part for calculating a correction amount based on the SAT detection value and the standard SAT value and correcting the current command value.

Claims

1. A control apparatus of an electric power steering apparatus, which calculates a current command value of a motor for applying steering assist force to a steering mechanism based on steering torque and a vehicle speed, and controls the motor based on the current command value, comprising:

an SAT detection part that detects or estimates a Self Aligning Torque (SAT) detection value;

a standard SAT calculation part that calculates a standard SAT value based on a steering angle and the vehicle speed; and

a correction part that calculates a correction amount based on the SAT detection value and the standard SAT value and corrects the current command value.

2. The control apparatus of the electric power steering apparatus as set forth in claim 1, wherein

the SAT detection part estimates the SAT detection value based on the steering torque, the current command value, a motor rotational speed and a rotational angular speed.

3. The control apparatus of the electric power steering apparatus as set forth in claim 1, wherein

the standard SAT calculation part has a model of an SAT change rate with respect to a steering angle.

4. The control apparatus of the electric power steering apparatus as set forth in claim 1, wherein

a deviation of the SAT detection value from the standard SAT value is calculated and the deviation is multiplied by a gain in response to the steering torque so as to calculate the correction amount.

5. A control apparatus of an electric power steering apparatus which calculates a current command value of a motor for applying steering assist force to a steering mechanism based on steering torque and a vehicle speed, and controls the motor based on the current command value, comprising:

an SAT detection part that detects or estimates an SAT detection value;

a standard SAT change rate detection part that detects a standard SAT change rate based on the SAT detection value and the vehicle speed; and

a correction part that calculates a correction amount based on a differential value of the SAT detection value and the standard SAT change rate and correcting the current command value.

6. The control apparatus of the electric power steering apparatus as set forth in claim 5, wherein

the SAT detection part estimates the SAT detection value based on a steering angle and the vehicle speed.

7. The control apparatus of the electric power steering apparatus as set forth in claim 5, wherein

the standard SAT calculation part has a model of an SAT change rate with respect to a steering angle.

8. The control apparatus of the electric power steering apparatus as set forth in claim 5, wherein

a deviation of the differential value from the standard SAT change rate is calculated and the deviation is multiplied by a gain in response to the steering torque so as to calculates the correction amount.

9. The control apparatus of the electric power steering apparatus as set forth in claim 5, wherein the correction part is responsive to the vehicle speed and the steering torque,