# US 10,864,941 B2 · Electric power steering apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,864,941 B2 - Document ID: US10864941B2 - Status: Granted - Kind: B2 - Application number: 16/785,818 - Filed: 2020-02-10 - Published: 2020-06-04 - Granted: 2020-12-15 - Earliest claimed: 2014-12-26 - Assignees: Nsk Ltd. - Applicants: Nsk Ltd. - Inventors: Takayoshi Sugawara; Yousuke Imamura; Masahiro Maeda - Web page: https://patentgrep.com/patent/US10864941B2 ## CPC - B62D 6/008: {Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications} - B62D 5/0463: {calculating assisting torque from the motor based on driver input} - B62D 5/0472: {for damping vibrations} - B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M) ## Abstract An electric power steering apparatus includes: a current command value determining section that determines a current command value based on steering torque and vehicle speed; a vibration extracting filter that extracts a first vibration component having a predetermined amplitude and first predetermined frequency range depending on motor angular velocity; a vibration extracting section that extracts a second vibration component having a second predetermined frequency range depending on motor angular acceleration; a first compensation value calculating section that calculates a first vibration suppression compensation value based on the first vibration component extracted by the vibration extracting filter; and a second compensation value calculating section that calculates a second vibration suppression compensation value based on the second vibration component; and suppresses vibrations of the motor by feeding back the first vibration suppression compensation value and the second vibration suppression compensation value calculated to the current command value. ## Claims ### Claim 1 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 vehicle speed; a vibration extracting filter that extracts a first vibration component having a predetermined amplitude and a first predetermined frequency range depending on a motor angular velocity; a vibration extracting section that extracts a second vibration component having a second predetermined frequency range depending on a motor angular acceleration; a first compensation value calculating section that calculates a first vibration suppression compensation value based on said first vibration component extracted by said vibration extracting filter; and a second compensation value calculating section that calculates a second vibration suppression compensation value based on said second vibration component extracted by said vibration extracting section; wherein vibrations of said motor are suppressed by feeding back said first vibration suppression compensation value calculated by said first compensation value calculating section and said second vibration suppression compensation value calculated by said second compensation value calculating section to said current command value determined by said current command value determining section; wherein said vibration extracting filter comprises an extraction inverse characteristic filter with window that calculates a vibration center value based on said motor angular velocity and depending on an inverse characteristic of said first predetermined frequency range, and extracts said first vibration component having said predetermined amplitude and said first predetermined frequency range based on a difference between said vibration center value and said motor angular velocity; wherein said extraction inverse characteristic filter with window comprises an inverse characteristic filter that has said inverse characteristic of said first 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 a command current parameter relating to motor current amount; wherein said extraction inverse characteristic filter with window inputs said motor angular velocity 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 motor angular velocity is within an amplitude window being a previous value of said vibration center value±said predetermined amplitude or not based on said motor angular velocity, said output of said inverse characteristic filter and said previous value of said vibration center value after setting said predetermined amplitude by increasing or decreasing said predetermined amplitude depending on said command current parameter relating to motor current amount, in a case of judging that said motor angular velocity 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 motor angular velocity is outside said amplitude window, outputs a value obtained by adding said predetermined amplitude to said motor angular velocity or subtracting said predetermined amplitude from said motor angular velocity as said vibration center value; wherein said vibration extracting section comprises a means of changing said second predetermined frequency range depending on said command current parameter relating to motor current amount; wherein said vibration extracting section outputs said second vibration component having said second predetermined frequency range after setting said second predetermined frequency range by changing said second predetermined frequency range depending on said command current parameter relating to motor current amount; and wherein said command current parameter relating to motor current amount is said current command value or said steering torque. ### Claim 2 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 vehicle speed; a vibration extracting filter that extracts a first vibration component having a predetermined amplitude and a first predetermined frequency range depending on a motor angular velocity; a vibration extracting section that extracts a second vibration component having a second predetermined frequency range depending on a motor angular acceleration; a first compensation value calculating section that calculates a first vibration suppression compensation value based on said first vibration component extracted by said vibration extracting filter; and a second compensation value calculating section that calculates a second vibration suppression compensation value based on said second vibration component extracted by said vibration extracting section; wherein vibrations of said motor are suppressed by feeding back said first vibration suppression compensation value calculated by said first compensation value calculating section and said second vibration suppression compensation value calculated by said second compensation value calculating section to said current command value determined by said current command value determining section; wherein said vibration extracting filter comprises an extraction inverse characteristic filter with window that calculates a vibration center value based on said motor angular velocity and depending on an inverse characteristic of said first predetermined frequency range, and extracts said first vibration component having said predetermined amplitude and said first predetermined frequency range based on a difference between said vibration center value and said motor angular velocity; wherein said extraction inverse characteristic filter with window comprises an inverse characteristic filter that has said inverse characteristic of said first 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 a command current parameter relating to motor current amount; wherein said extraction inverse characteristic filter with window inputs said motor angular velocity 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 motor angular velocity is within an amplitude window being a previous value of said vibration center value±said predetermined amplitude or not based on said motor angular velocity, said output of said inverse characteristic filter and said previous value of said vibration center value after setting said predetermined amplitude by increasing or decreasing said predetermined amplitude depending on said command current parameter relating to motor current amount, in a case of judging that said motor angular velocity 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 motor angular velocity is outside said amplitude window, outputs a value obtained by adding said predetermined amplitude to said motor angular velocity or subtracting said predetermined amplitude from said motor angular velocity as said vibration center value; wherein said vibration extracting section comprises a means of changing said second predetermined frequency range depending on said command current parameter relating to motor current amount; wherein said vibration extracting section outputs said second vibration component having said second predetermined frequency range after setting said second predetermined frequency range by changing said second predetermined frequency range depending on said command current parameter relating to motor current amount; wherein said command current parameter relating to motor current amount is said current command value; and wherein said amplitude window judging section sets said predetermined amplitude so as to increase said predetermined amplitude depending on an increase in said current command value.