# US 2022/0032995 A1 · Electric power steering device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2022/0032995 A1 - Document ID: US20220032995A1 - Status: Published application - Kind: A1 - Application number: 17/500,505 - Filed: 2021-10-13 - Published: 2022-02-03 - Earliest claimed: 2019-05-16 - Assignees: Hitachi Astemo, Ltd. - Applicants: Hitachi Astemo, Ltd. - Inventors: Masaaki MINAKAWA; Miki KOHSO - Web page: https://patentgrep.com/patent/US20220032995A1 ## CPC - B62D 5/0463: {calculating assisting torque from the motor based on driver input} - B62D 6/008: {Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications} - 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 Provided is a feature which allows an electric power steering device to improve the steering feel. The electric power steering device includes: a basic control amount calculating section configured to calculate a basic control amount corresponding to steering by a driver; a frictional force calculating section configured to calculate, by using a friction model, a frictional force corresponding to a wheel angle-related value, which is a value relating to a wheel angle of a steering device, and calculate a friction-originated control amount, which originates from the calculated frictional force; and a control amount calculating section configured to calculate a steering control amount in accordance with the basic control amount and the friction-originated control amount. ## Claims ### Claim 1 An electric power steering control device for calculating a steering control amount for steering a steering device, the electric power steering control device, comprising: a basic control amount calculating section configured to calculate a basic control amount corresponding to steering by a driver; a frictional force calculating section configured to calculate, by using a friction model, a frictional force corresponding to a wheel angle-related value, which is a value relating to a wheel angle of the steering device, and calculate a friction-originated control amount, which originates from the calculated frictional force; and a control amount calculating section configured to calculate the steering control amount in accordance with the basic control amount and the friction-originated control amount calculated by the frictional force calculating section, the friction model being a model including a spring component and a Coulomb friction component connected in series, the frictional force calculating section being configured to: calculate the frictional force by using a plurality of models each being the model including the spring component and the Coulomb friction component connected in series, the plurality of models having respective spring constants and respective Coulomb friction forces, the plurality of models having respective ratios between the respective Coulomb friction forces and the respective spring constants, the ratios being different from each other; and output, in accordance with the wheel angle-related value, the frictional force which is to be output by driving the plurality of models, by sliding the plurality of models in ascending order of the ratios. ### Claim 2 (depends on 1) The electric power steering control device according to claim 1, wherein the wheel angle-related value is calculated from a signal indicating a motor rotation angle of an electric motor, which is configured to apply, to the steering device, an assist torque or a reaction torque on a basis of the steering control amount calculated by the control amount calculating section. ### Claim 3 (depends on 1) The electric power steering control device according to claim 1, further comprising an existing friction cancel amount calculating section configured to calculate a friction cancel control amount for cancelling friction generated in the steering device, wherein the control amount calculating section is configured to calculate the steering control amount in accordance with the basic control amount, the friction-originated control amount, and the friction cancel control amount. ### Claim 4 (depends on 3) The electric power steering control device according to claim 3, wherein the control amount calculating section is configured to calculate the steering control amount by subtracting the friction cancel control amount from a result of adding the basic control amount and the friction-originated control amount. ### Claim 5 (depends on 3) The electric power steering control device according to claim 3, wherein the control amount calculating section is configured to calculate a correction control amount by subtracting the friction-originated control amount from the friction cancel control amount, and calculate the steering control amount by subtracting the correction control amount from the basic control amount. ### Claim 6 (depends on 3) The electric power steering control device according to claim 3, wherein the existing friction cancel amount calculating section is configured to calculate the friction cancel control amount in accordance with a steering torque generated when the steering device is steered. ### Claim 7 (depends on 1) An electric power steering device, comprising an electric power steering control device according to claim 1. ### Claim 8 (depends on 2) The electric power steering control device according to claim 2, further comprising an existing friction cancel amount calculating section configured to calculate a friction cancel control amount for cancelling friction generated in the steering device, wherein the control amount calculating section is configured to calculate the steering control amount in accordance with the basic control amount, the friction-originated control amount, and the friction cancel control amount. ### Claim 9 (depends on 8) The electric power steering control device according to claim 8, wherein the control amount calculating section is configured to calculate the steering control amount by subtracting the friction cancel control amount from a result of adding the basic control amount and the friction-originated control amount. ### Claim 10 (depends on 8) The electric power steering control device according to claim 8, wherein the control amount calculating section is configured to calculate a correction control amount by subtracting the friction-originated control amount from the friction cancel control amount, and calculate the steering control amount by subtracting the correction control amount from the basic control amount. ### Claim 11 (depends on 8) The electric power steering control device according to claim 8, wherein the existing friction cancel amount calculating section is configured to calculate the friction cancel control amount in accordance with a steering torque generated when the steering device is steered. ### Claim 12 (depends on 2) An electric power steering device, comprising an electric power steering control device according to claim 2. ### Claim 13 (depends on 3) An electric power steering device, comprising an electric power steering control device according to claim 3. ### Claim 14 (depends on 4) An electric power steering device, comprising an electric power steering control device according to claim 4. ### Claim 15 (depends on 5) An electric power steering device, comprising an electric power steering control device according to claim 5. ### Claim 16 (depends on 6) An electric power steering device, comprising an electric power steering control device according to claim 6. ### Claim 17 (depends on 8) An electric power steering device, comprising an electric power steering control device according to claim 8. ### Claim 18 (depends on 9) An electric power steering device, comprising an electric power steering control device according to claim 9. ### Claim 19 (depends on 10) An electric power steering device, comprising an electric power steering control device according to claim 10. ### Claim 20 (depends on 11) An electric power steering device, comprising an electric power steering control device according to claim 11.