Electric power steering apparatus

An electric power steering apparatus that provides a steering system of a vehicle with an assist force generated by a motor, comprising:

• a current command value determining section that determines a current command value based on a steering torque and a velocity;
• a vibration extraction filter that extracts a vibration component having a predetermined amplitude and a predetermined frequency range depending on an electric power steering state parameter;
• and
• a compensation value determining section that determines a vibration suppression compensation value based on said vibration component extracted by said vibration extraction filter,
• wherein vibrations of said motor are suppressed by feeding back said vibration suppression compensation value determined by said compensation value determining section to said current command value determined by said current command value determining section,
• wherein said vibration extraction filter
• comprises an extraction inverse characteristic filter with window that calculates a vibration center value based on said electric power steering state parameter and depending on an inverse characteristic of said predetermined frequency range, and
• extracts said vibration component having said predetermined amplitude and said predetermined frequency range based on a difference between said vibration center value and said electric power steering state parameter,
• wherein said extraction inverse characteristic filter with window comprises an inverse characteristic filter that has said inverse characteristic of said predetermined frequency range and an amplitude window judging section that said predetermined amplitude is preset,
• wherein said extraction inverse characteristic filter with window inputs said electric power steering state parameter to said inverse characteristic filter and then outputs an output of said inverse characteristic filter to said amplitude window judging section,
• wherein said amplitude window judging section
• performs an amplitude window judging process that judges whether said electric power steering state parameter is within an amplitude window being said previous value of said vibration center value±said predetermined amplitude or not based on said electric power steering state parameter, said output of said inverse characteristic filter and a previous value of said vibration center value,
• in a case of judging that said electric power steering state parameter is within said amplitude window, outputs said output of said inverse characteristic filter as said vibration center value, and
• in a case of judging that said electric power steering state parameter is outside said amplitude window, outputs a value obtained by adding said predetermined amplitude to said electric power steering state parameter or subtracting said predetermined amplitude from said electric power steering state parameter as said vibration center value.

An electric power steering apparatus that provides a steering system of a vehicle with an assist force generated by a motor, comprising:

• a current command value determining section that determines a current command value based on a steering torque and a velocity;
• a vibration extraction filter that extracts a vibration component having a predetermined amplitude and a predetermined frequency range depending on an electric power steering state parameter;
• and
• a compensation value determining section that determines a vibration suppression compensation value based on said vibration component extracted by said vibration extraction filter,
• wherein vibrations of said motor are suppressed by feeding back said vibration suppression compensation value determined by said compensation value determining section to said current command value determined by said current command value determining section,
• wherein said vibration extraction filter
• comprises an extraction inverse characteristic filter with window that calculates a vibration center value based on said electric power steering state parameter and depending on an inverse characteristic of said predetermined frequency range, and
• extracts said vibration component having said predetermined amplitude and said predetermined frequency range based on a difference between said vibration center value and said electric power steering state parameter,
• wherein said extraction inverse characteristic filter with window comprises an inverse characteristic filter that has said inverse characteristic of said predetermined frequency range and an amplitude window judging section that comprises a means of increasing or decreasing said predetermined amplitude that is preset depending on an electric power steering state parameter relating to motor current amount,
• wherein said extraction inverse characteristic filter with window inputs said electric power steering state parameter to said inverse characteristic filter and then outputs an output of said inverse characteristic filter to said amplitude window judging section,
• wherein said amplitude window judging section
• performs an amplitude window judging process that judges whether said electric power steering state parameter is within an amplitude window being said previous value of said vibration center value±said predetermined amplitude or not based on said electric power steering state parameter, said output of said inverse characteristic filter and a previous value of said vibration center value after setting said predetermined amplitude by increasing or decreasing said predetermined amplitude depending on said electric power steering state parameter relating to motor current amount,
• in a case of judging that said electric power steering state parameter is within said amplitude window, outputs said output of said inverse characteristic filter as said vibration center value, and
• in a case of judging that said electric power steering state parameter is outside said amplitude window, outputs a value obtained by adding said predetermined amplitude to said electric power steering state parameter or subtracting said predetermined amplitude from said electric power steering state parameter as said vibration center value.

The electric power steering apparatus that provides a steering system of a vehicle with an assist force generated by a motor, comprising:

• a current command value determining section that determines a current command value based on a steering torque and a velocity;
• a vibration extraction filter that extracts a vibration component having a predetermined amplitude and a predetermined frequency range depending on an electric power steering state parameter;
• and
• a compensation value determining section that determines a vibration suppression compensation value based on said vibration component extracted by said vibration extraction filter,
• wherein vibrations of said motor are suppressed by feeding back said vibration suppression compensation value determined by said compensation value determining section to said current command value determined by said current command value determining section,
• wherein said vibration extraction filter
• comprises an extraction inverse characteristic filter with window that calculates a vibration center value based on said electric power steering state parameter and depending on an inverse characteristic of said predetermined frequency range, and
• extracts said vibration component having said predetermined amplitude and said predetermined frequency range based on a difference between said vibration center value and said electric power steering state parameter,
• wherein said extraction inverse characteristic filter with window comprises an inverse characteristic filter that has said inverse characteristic of said predetermined frequency range and an amplitude window judging section that comprises a means of increasing or decreasing said predetermined amplitude that is preset depending on said velocity,
• wherein said extraction inverse characteristic filter with window inputs said electric power steering state parameter to said inverse characteristic filter and then outputs an output of said inverse characteristic filter to said amplitude window judging section,
• wherein said amplitude window judging section
• performs an amplitude window judging process that judges whether said electric power steering state parameter is within an amplitude window being said previous value of said vibration center value±said predetermined amplitude or not based on said electric power steering state parameter, said output of said inverse characteristic filter and a previous value of said vibration center value after setting said predetermined amplitude by increasing or decreasing said predetermined amplitude depending on said velocity,
• in a case of judging that said electric power steering state parameter is within said amplitude window, outputs said output of said inverse characteristic filter as said vibration center value, and
• in a case of judging that said electric power steering state parameter is outside said amplitude window, outputs a value obtained by adding said predetermined amplitude to said electric power steering state parameter or subtracting said predetermined amplitude from said electric power steering state parameter as said vibration center value.