# US 10,864,939 B2 · Steering assist apparatus of vehicle and method for steering assist apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,864,939 B2 - Document ID: US10864939B2 - Status: Granted - Kind: B2 - Application number: 15/958,825 - Filed: 2018-04-20 - Published: 2018-10-25 - Granted: 2020-12-15 - Earliest claimed: 2017-04-21 - Assignees: Denso Corporation - Applicants: Denso Corporation - Inventors: Yosuke Hirate; Daiji Watanabe; Hisaya Akatsuka; Toshiya Kabayama - Web page: https://patentgrep.com/patent/US10864939B2 ## CPC - B62D 6/003: {in order to control vehicle yaw movement, i.e. around a vertical axis (B62D6/007 takes precedence)} - B62D 5/008: {Changing the transfer ratio between the steering wheel and the steering gear by variable supply of energy, e.g. by using a superposition gear} - B62D 15/022: {on or near the connection between the steering wheel and steering column} - B62D 15/025: {Active steering aids, e.g. helping the driver by actively influencing the steering system after environment evaluation (B62D1/28 takes precedence)} - B62D 15/0285: {Parking performed automatically} - G05D 1/0212: {with means for defining a desired trajectory (involving a plurality of land vehicles G05D1/0287)} - B62D 3/12: of rack-and-pinion type - 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) - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES ## Abstract A steering assist apparatus on a vehicle is provided, including a steering drive unit that drives a steering apparatus; a steering control unit that executes an automatic steering mode in which the steering drive unit is controlled such that a turning angle is determined based on at least either a running state of the vehicle or road information to accomplish the determined turning angle; and a transmission ratio determining unit that determines, based on at least either a running state of the vehicle or the road information, a first transmission ratio in the automatic steering mode to be a value different from a second transmission ratio in a manual steering mode in which the steering apparatus operates in accordance with the steering angle inputted via a steering input apparatus. ## Claims ### Claim 1 A steering assist apparatus of a vehicle provided with a steering input apparatus that inputs a steering angle and a steering apparatus that steers wheels of the vehicle with a turning angle, the steering input apparatus and the steering apparatus performing a differential operation with a transmission ratio which is a ratio of a change amount of the steering angle to a change amount of the turning angle, the steering assist apparatus comprising: a steering drive that drives the steering apparatus; a processor configured to perform functions including: a steering control that executes an automatic steering mode in which the steering drive is controlled such that a turning angle is determined based on at least either a running state of the vehicle or road information to accomplish the turning angle; and a transmission ratio determination that determines, based on a turning curvature and at least either a running state of the vehicle or the road information, a first transmission ratio in the automatic steering mode to be a value different from a second transmission ratio in a manual steering mode in which the steering apparatus operates in accordance with the steering angle inputted via the steering input apparatus, wherein the transmission ratio determination changes the transmission ratio such that the larger the turning curvature, the larger the transmission ratio is. ### Claim 2 (depends on 1) The steering assist apparatus according to claim 1, wherein the transmission ratio determination further determines the first transmission ratio based on the turning angle. ### Claim 3 (depends on 2) The steering assist apparatus according to claim 2, wherein the transmission ratio determination unit determines the first transmission ratio such that the larger the turning angle, the larger the first transmission ratio is. ### Claim 4 (depends on 1) The steering assist apparatus according to claim 1, wherein the transmission ratio determination unit determines the first transmission ratio based on a change rate of the turning angle. ### Claim 5 (depends on 4) The steering assist apparatus according to claim 4, wherein the transmission ratio determination determines the first transmission ratio such that the larger the change rate of the turning angle, the larger the first transmission ratio is. ### Claim 6 (depends on 1) The steering assist apparatus according to claim 1, wherein the transmission ratio determination further determines the first transmission ratio based on a travelling speed of the vehicle. ### Claim 7 (depends on 1) The steering assist apparatus according to claim 1, wherein the transmission ratio determination further determines the first transmission ratio based on a confidence degree of the steering assist apparatus. ### Claim 8 (depends on 7) The steering assist apparatus according to claim 7, wherein the transmission ratio determination determines the first transmission ratio such that the smaller the confidence degree, the smaller the first transmission ratio is. ### Claim 9 (depends on 1) The steering assist apparatus according to claim 1, further comprising: a variable steering angle apparatus that generates a differential angle between the steering angle and the turning angle; and the steering control controls the variable steering angle apparatus so as to further generate a differential angle based on the first transmission ratio or the second transmission ratio. ### Claim 10 (depends on 9) The steering assist apparatus according to claim 9, wherein the steering control controls, when the vehicle changes a direction from straight forward travelling to turning travelling or from the turning traveling to the straight forward travelling, the variable steering angle apparatus with the first transmission ratio to change the steering angle before changing the turning angle. ### Claim 11 (depends on 1) The steering assist apparatus according to claim 1, wherein the steering control further determines, during the manual steering mode, the turning angle by using the steering angle and the second transmission ratio, and controls the steering drive so as to accomplish the turning angle. ### Claim 12 (depends on 11) The steering assist apparatus according to claim 11, further comprising: a steering input drive apparatus that drives the steering input apparatus; and the steering control further controls, when the vehicle changes a direction from straight forward travelling to turning travelling or from the turning traveling to the straight forward travelling, the steering input drive apparatus with the first transmission ratio so as to change the steering angle before changing the turning angle. ### Claim 13 A computer-implemented method for steering assist of a vehicle provided with a steering input apparatus that inputs a steering angle and a steering apparatus that steers wheels of the vehicle with a turning angle, the steering input apparatus and the steering apparatus performing a differential operation with a transmission ratio which is a ratio of a change amount of the steering angle to a change amount of the turning angle, the method comprising steps of: determining, based on at least either a running state of the vehicle or road information, a first transmission ratio in an automatic steering mode to be a value different from a second transmission ratio in a manual steering mode in which the steering apparatus operates in accordance with the steering angle inputted via the steering input apparatus; executing the automatic steering mode in which a steering drive is controlled such that a turning angle is determined based on a turning curvature and at least either the running state of the vehicle or the road information to accomplish the turning angle; and changing the transmission ratio such that the larger the turning curvature, the larger the transmission ratio is.