Motor-driven power steering control apparatus

• US 7,128,185 B2
• Filed: 05/04/2005
• Issued: 10/31/2006
• Est. Priority Date: 10/07/2003
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Kurishige, Masahiko, Fujimoto, Chiaki, Tsutsumi, Kazumichi, Inoue, Noriyuki, Satake, Toshihide
• Primary Examiner(s): Morris, Lesley D.
• Assistant Examiner(s): YEAGLEY, DANIEL S
• Application Number:
  US11/120,947
• Publication Number:
  US 20050189897A1
• Time in Patent Office: 545 Days
• Field of Search: 180/443, 180/446, 701/41, 701/42, 318/432, 318/433
• US Class Current: 180/446
• CPC Class Codes: B62D 5/0484 for reaction to failures, e.g. limp home

Abstract

A motor-driven power steering control apparatus assuring consistently comfortable steering operation of a motor vehicle includes a steering state detector (10), a motor drive command value arithmetic device (20), a trouble detector (40), a motor drive command value corrector (51, 52) for decrementing a motor drive command value outputted from the motor drive command value corrector (51) from a predetermined initial value as a function of time lapse when a trouble detection signal is outputted from the trouble detector (40), and an element (30) for driving an assist motor in conformance with the output of the motor drive command value corrector (51, 52). The motor drive command value corrector (51, 52) includes a low-pass filter (515) for smoothing the motor drive command value. A value acquired through the low-pass filter (515) is employed as the predetermined initial value.

Claims

1. A motor-driven power steering control apparatus, comprising:

steering state detecting means for detecting a steering state of a steering system;

motor drive command value arithmetic means for arithmetically determining a motor drive command value for an assist motor of said steering system on the basis of a detection signal outputted from said steering state detecting means;

trouble detecting means designed for outputting a trouble detection signal upon detection of a trouble in said motor-driven power steering control apparatus;

motor drive command value correcting means for processing said motor drive command value so that said motor drive command value is decremented from a predetermined initial value as a function of time lapse when the trouble detection signal is outputted from said trouble detecting means; and

motor driving means for driving said assist motor on the basis of the motor drive command value outputted from said motor drive command value correcting means,

wherein said motor drive command value correcting means includes

smoothing means for smoothing said motor drive command value outputted from said motor drive command value arithmetic means, and

wherein a value acquired through said smoothing means is employed as said predetermined initial value, and

steering angle detecting means for detecting a steering state of said steering system,

wherein said motor drive command value correcting means is so designed that when said motor drive command value is processed to be decremented from said predetermined initial value as a function of time lapse, said motor drive command value correcting means processes said motor drive command value by taking into consideration decrementing of a steering angle detected by said steering angle detecting means.

2. A motor-driven power steering control apparatus, comprising:

steering state detecting means for detecting a steering state of a steering system;

motor drive command value arithmetic means for arithmetically determining a motor drive command value for an assist motor of said steering system on the basis of a detection signal outputted from said steering state detecting means;

trouble detecting means designed for outputting a trouble detection signal upon detection of a trouble in said motor-driven power steering control apparatus;

motor drive command value correcting means for processing said motor drive command value so that said motor drive command value is decremented from a predetermined initial value as a function of time lapse when the trouble detection signal is outputted from said trouble detecting means; and

motor driving means for driving said assist motor on the basis of the motor drive command value outputted from said motor drive command value correcting means,

wherein said motor drive command value correcting means includes

smoothing means for smoothing said motor drive command value outputted from said motor drive command value arithmetic means, and

wherein a value acquired through said smoothing means is employed as said predetermined initial value, and

steering neutral point detecting means for detecting a steering neutral point,

wherein said motor drive command value correcting means is so designed that when said steering neutral point detecting means detects the steering neutral point, said motor drive command value correcting means sets instantaneously to zero the motor drive command value which is being decremented from said predetermined initial value as a function of time lapse.