# US 12,594,986 B2 · Vehicle steering assist device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,594,986 B2 - Document ID: US12594986B2 - Status: Granted - Kind: B2 - Application number: 18/112,134 - Filed: 2023-02-21 - Published: 2023-11-02 - Granted: 2026-04-07 - Earliest claimed: 2022-04-28 - Assignees: Toyota Jidosha Kabushiki Kaisha - Applicants: Toyota Jidosha Kabushiki Kaisha - Inventors: Shintaro Saigo; Shusaku Sugamoto; Satoshi Inoue - Web page: https://patentgrep.com/patent/US12594986B2 ## CPC - B62D 5/0466: {for returning the steering wheel to neutral position} - B62D 5/0421: {Electric motor acting on or near steering gear} - B62D 5/0463: {calculating assisting torque from the motor based on driver input} - B62D 6/002: {computing target steering angles for front or rear wheels (B62D7/159 takes precedence)} - 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 A vehicle steering assist device in which the steering assist ECU calculates a target steering angle for driving a vehicle along a traveling path, and is vehicle steering assist device that a calculates a target steering guide torque for facilitating the steering angle to become a target steering angle by reducing a return torque for urging the steering wheel to a neutral position in an area where the steering angle is smaller than the target steering angle, wherein when the steering angular velocity is higher than the target steering angular velocity, the steering support ECU calculates a target steering angular velocity control torque acting in a direction opposite to a direction in which the steering angle changes, and controls the control steering torque generating device so as to generate a control steering torque including a sum of the target steering guide torque and the target steering angular velocity control torque. ## Claims ### Claim 1 A vehicle steering assist device comprising: a turning device configured to turn a turning wheel in accordance with a steering operation amount applied to a steering input member by a driver, and configured to apply a return torque for urging the steering input member to a neutral position to the steering input member, the return torque being a torque that increases as the steering operation amount increases; a control steering torque generating device that generates a control steering torque for correcting the return torque; a control unit that controls the control steering torque generating device; a curvature degree acquisition device that acquires a curvature degree of a traveling road in front of a vehicle; a vehicle speed detecting device; and a steering assist switch, wherein when the steering assist switch is turned on, the control unit calculates a target steering angle for causing the vehicle to travel along a traveling road based on the curvature degree of the traveling road acquired by the curvature degree acquisition device and a vehicle speed detected by the vehicle speed detecting device, wherein the control unit calculates a target steering guide torque for facilitating a steering angle to become the target steering angle by reducing the return torque in an area where the steering angle is smaller than the target steering angle, wherein the control unit is configured to control the control steering torque generating device to cause the control steering torque generating device to generate the control steering torque including the target steering guiding torque, wherein the control unit calculates an actual steering angular velocity based on the steering angle when the steering assist switch is turned on, wherein the control unit calculates a target steering angular velocity based on the target steering angle, wherein when the actual steering angular velocity is higher than the target steering angular velocity, the control unit calculates a target steering angular velocity control torque acting in a direction opposite to a direction in which the actual steering angle changes, and wherein the control unit controls the control steering torque generating device to cause the control steering torque generating device to generate a control steering torque including a sum of the target steering guide torque and the target steering angular velocity control torque, wherein the control unit is configured to: calculate a determination reference value for a steering angular velocity based on a maximum steering angular velocity when the vehicle travels on a curve of the traveling road, in a situation where the steering assist switch is turned off, reduce a magnitude of the target steering guide torque when the actual steering angular velocity is smaller than the target steering angular velocity and an index value of the actual steering angular velocity is higher than the determination reference value, in a situation where the steering assist switch is turned on; and control the control steering torque generating device to cause the control steering torque generating device to generate a control steering torque that includes the target steering guide torque with a reduced magnitude of the target steering guide torque and that does not include the target steering angular velocity control torque. ### Claim 2 (depends on 1) The vehicle steering assist device according to claim 1, wherein the control unit is configured to calculate the target steering angular velocity control torque so as to increase the target steering angular velocity control torque as a difference between the actual steering angular velocity and the target steering angular velocity increases. ### Claim 3 (depends on 1) The vehicle steering assist device according to claim 1, wherein the control unit is configured to: calculate a positive correction coefficient smaller than 1 such that the correction coefficient becomes smaller as a magnitude of a difference between the index value of the actual steering angular velocity and the determination reference value becomes larger; and reduce the target steering guide torque by multiplying the target steering guide torque by the correction coefficient. ### Claim 4 (depends on 1) The vehicle steering assist device according to claim 1, wherein the control unit is configured to: control the control steering torque generating device to cause the control steering torque generating device to generate a control steering torque that includes the target steering guide torque and that does not include the target steering angular velocity control torque, when the actual steering angular velocity is smaller than the target steering angular velocity and an index value of the actual steering angular velocity is not higher than the determination reference value, in a situation where the steering assist switch is turned on. ### Claim 5 (depends on 1) The vehicle steering assist device according to claim 1, wherein the index value of the actual steering angular velocity is a half-dimensionless steering angular velocity obtained by dividing a current steering angular velocity by a current steering angle. ### Claim 6 (depends on 1) The vehicle steering assist device according to claim 1, wherein the determination reference value is a value obtained based on a half-dimensionless maximum steering angular velocity obtained by dividing a maximum value of a magnitude of a steering angular velocity when the vehicle travels on a curve of the traveling road in a state where the steering assist switch is turned off by a maximum value of a magnitude of a steering angle. ### Claim 7 (depends on 6) The vehicle steering assist device according to claim 6, wherein the control unit is configured to calculate the determination reference value by calculating one of an average value of the half-dimensionless maximum steering angular velocity, a median of the half-dimensionless maximum steering angular velocity, a maximum value of the half-dimensionless maximum steering angular velocity, and a percentile value of the half-dimensionless maximum steering angular velocity, in a state in which the number of the half-dimensionless maximum steering angular velocities is equal to or more than the number of a reference. ### Claim 8 A vehicle steering assist device comprising: a turning device configured to turn a turning wheel in accordance with a steering operation amount applied to a steering input member by a driver, and configured to apply a return torque for urging the steering input member to a neutral position to the steering input member, the return torque being a torque that increases as the steering operation amount increases; a control steering torque generating device that generates a control steering torque for correcting the return torque; a control unit that controls the control steering torque generating device; a curvature degree acquisition device that acquires a curvature degree of a traveling road in front of a vehicle; a vehicle speed detecting device; and a steering assist switch, wherein when the steering assist switch is turned on, the control unit calculates a target steering angle for causing the vehicle to travel along a traveling road based on the curvature degree of the traveling road acquired by the curvature degree acquisition device and a vehicle speed detected by the vehicle speed detecting device, wherein the control unit calculates a target steering guide torque for facilitating a steering angle to become the target steering angle by reducing the return torque in an area where the steering angle is smaller than the target steering angle, wherein the control unit is configured to control the control steering torque generating device to cause the control steering torque generating device to generate the control steering torque including the target steering guiding torque, wherein the control unit calculates an actual steering angular velocity based on the steering angle when the steering assist switch is turned on, wherein the control unit calculates a target steering angular velocity based on the target steering angle, wherein when the actual steering angular velocity is higher than the target steering angular velocity, the control unit calculates a target steering angular velocity control torque acting in a direction opposite to a direction in which the actual steering angle changes, and wherein the control unit controls the control steering torque generating device to cause the control steering torque generating device to generate a control steering torque including a sum of the target steering guide torque and the target steering angular velocity control torque, wherein the control unit is configured to: calculate a determination reference value for a steering angular velocity based on a maximum steering angular velocity when the vehicle travels on a curve of the traveling road, in a situation where the steering assist switch is turned off; and control the control steering torque generating device to cause the control steering torque generating device to generate a control steering torque that includes the target steering guide torque and that does not include the target steering angular velocity control torque, when the actual steering angular velocity is smaller than the target steering angular velocity and an index value of the actual steering angular velocity is not higher than the determination reference value, in a situation where the steering assist switch is turned on. ### Claim 9 (depends on 8) The vehicle steering assist device according to claim 8, wherein the index value of the actual steering angular velocity is a half-dimensionless steering angular velocity obtained by dividing a current steering angular velocity by a current steering angle. ### Claim 10 (depends on 8) The vehicle steering assist device according to claim 8, wherein the determination reference value is a value obtained based on a half-dimensionless maximum steering angular velocity obtained by dividing a maximum value of a magnitude of a steering angular velocity when the vehicle travels on a curve of the traveling road in a state where the steering assist switch is turned off by a maximum value of a magnitude of a steering angle. ### Claim 11 (depends on 10) The vehicle steering assist device according to claim 10, wherein the control unit is configured to calculate the determination reference value by calculating one of an average value of the half-dimensionless maximum steering angular velocity, a median of the half-dimensionless maximum steering angular velocity, a maximum value of the half-dimensionless maximum steering angular velocity, and a percentile value of the half-dimensionless maximum steering angular velocity, in a state in which the number of the half-dimensionless maximum steering angular velocities is equal to or more than the number of a reference.