# US 2014/0207337 A1 · 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 2014/0207337 A1 - Document ID: US20140207337A1 - Status: Published application - Kind: A1 - Application number: 14/141,163 - Filed: 2013-12-26 - Published: 2014-07-24 - Earliest claimed: 2013-01-18 - Assignees: Jtekt Corporation - Applicants: Jtekt Corporation - Inventors: Terutaka TAMAIZUMI - Web page: https://patentgrep.com/patent/US20140207337A1 ## 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: 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 The control apparatus calculates the first assist component on the basis of the steering torque. The control apparatus calculates the turning angle command value from the steering torque and the first assist component on the basis of the ideal model, executes turning angle feedback control for matching the actual turning angle with the turning angle command value, and calculates the second assist component. The control apparatus adds the second assist component to the first assist component to calculate the assist command value. When the deviation between the actual turning angle and the turning angle command value is out of the allowable range, the control apparatus changes the ideal model to remove the second assist component from the assist command value and enhance convergence of the turning angle feedback control system. ## Claims ### Claim 1 An electric power steering apparatus comprising: an assist mechanism for applying assist force of a motor to a steering mechanism of a vehicle, and a control unit for controlling drive of the motor on the basis of an assist command value, wherein the control unit has: a basic assist component calculating unit for calculating a first assist component on the basis of steering torque applied to the steering mechanism; a turning angle command value calculating unit for calculating a turning angle command value on the basis of an ideal model obtained by modeling an ideal turning angle of a steerable wheel corresponding to input information including steering torque applied to the steering mechanism; a turning angle feedback control unit for calculating a second assist component by execution of turning angle feedback control for matching a turning angle of the steerable wheel with the turning angle command value; and an assist command value calculating unit for calculating the assist command value based on a value obtained by adding the second assist component to the first assist component, wherein when a deviation between the turning angle of the steerable wheel and the turning angle command value is out of an allowable range, the control unit removes the second assist component from the assist command value and changes the ideal model to enhance convergence in the turning angle feedback control system. ### Claim 2 (depends on 1) The electric power steering apparatus according to claim 1, wherein the ideal model is constituted of an ideal model representing an addition value of the steering torque and the first assist component as an addition value of a plurality of terms including a spring term proportional to the turning angle and a viscosity term proportional to a first-order time differential value of the turning angle, and the ideal model is changed by changing at least one of a constant of proportionality of the spring term and a constant of proportionality of the viscosity term. ### Claim 3 (depends on 1) The electric power steering apparatus according to claim 1, wherein the turning angle command value calculating unit continues calculation of the turning angle command value and the turning angle feedback control unit continues calculation of the second assist component while the second assist component is removed from the assist command value. ### Claim 4 (depends on 1) The electric power steering apparatus according to claim 1, wherein the control unit further comprises a switching determination unit for outputting a first switching signal when the deviation between the turning angle of the steerable wheel and the turning angle command value is within the allowable range and outputting a second switching signal when the deviation is out of the allowable range, and the control unit performs control so that the second assist component is removed from the assist command value in accordance with the second switching signal and performs control so that the second assist component is included in the assist command value in accordance with the first switching signal. ### Claim 5 (depends on 1) The electric power steering apparatus according to claim 1, wherein the turning angle command value calculating unit obtains driving torque by adding a corrected first assist component to steering torque and calculates a turning angle command value on the basis of an ideal model obtained by modeling an ideal turning angle corresponding to the driving torque. ### Claim 6 (depends on 1) The electric power steering apparatus according to claim 1, wherein the control unit further comprises a road information compensation unit for calculating a correction value to be used for correcting the first assist component, and the road information compensation unit calculates the correction value on the basis of the second assist component and a vehicle speed. ### Claim 7 (depends on 6) The electric power steering apparatus according to claim 6, wherein the road information compensation unit calculates the correction value so that the second assist component included in the assist command value is decreased as the vehicle speed becomes lower.