# US 12,110,072 B2 · Steering control device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,110,072 B2 - Document ID: US12110072B2 - Status: Granted - Kind: B2 - Application number: 17/791,250 - Filed: 2020-12-08 - Published: 2023-11-02 - Granted: 2024-10-08 - Earliest claimed: 2020-01-24 - Assignees: Hitachi Astemo, Ltd. - Applicants: Hitachi Astemo, Ltd. - Inventors: Go Sakayori; Kenta Maeda; Tomoaki Fujibayashi; Hiroki Sonoda - Web page: https://patentgrep.com/patent/US12110072B2 ## CPC - B62D 6/008: {Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications} - B62D 6/04: responsive only to forces disturbing the intended course of the vehicle, e.g. forces acting transversely to the direction of vehicle travel - 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 present disclosure provides a steering control device capable of transmitting an appropriate reaction force by a driver via a steering wheel and improving the stability of a vehicle. Provided is a steering control device 100 for controlling a reaction force actuator 16 that generates a reaction force against an operation of a driver in a steering wheel 13 of a vehicle 10. The steering control device 100 increases the reaction force in a nonlinear region where a cornering force characteristic that is the relationship between the slip angle and the lateral force of tires 11 of the vehicle 10 becomes nonlinear, more than the reaction force in a linear region where the cornering force characteristic becomes linear. ## Claims ### Claim 1 A steering control device for controlling a reaction force actuator that generates a reaction force against an operation of a driver in a steering wheel of a vehicle, wherein the reaction force in a nonlinear region where a cornering force characteristic that is the relationship between the slip angle and the lateral force of tires of the vehicle becomes nonlinear is increased more than that in a linear region where the cornering force characteristic becomes linear, wherein the steering angle of the steering wheel operated by the driver is acquired, wherein the reaction force is increased according to an increase in the steering angle in the nonlinear region, wherein the lateral acceleration of the vehicle and turning torque for turning the tires are acquired, wherein the rate of change between the increased amount of the lateral acceleration and the increased amount of the turning torque is calculated in a region where the relationship between the lateral acceleration and the turning torque becomes linear, and wherein the nonlinear degree of the cornering force characteristic is calculated on the basis of the difference between a reference turning torque obtained by multiplying the rate of change by the lateral acceleration and the turning torque. ### Claim 2 (depends on 1) The steering control device according to claim 1, wherein the speed of the vehicle is acquired to calculate a reference reaction force against the operation of the steering wheel by the driver on the basis of the speed and the steering angle, wherein an additional reaction force against the operation of the steering wheel by the driver is calculated on the basis of the nonlinear degree, and wherein the reaction force is calculated by adding the reference reaction force and the additional reaction force. ### Claim 3 (depends on 1) The steering control device according to claim 1, wherein the speed of the vehicle is acquired, and wherein in the case where the lateral acceleration is equal to or larger than a threshold value, the speed is equal to or larger than a threshold value, and the cornering force characteristic is in the linear region, the rate of the change is learned. ### Claim 4 (depends on 3) The steering control device according to claim 3, wherein the rate of change is calculated by a sequential least squares method. ### Claim 5 (depends on 1) The steering control device according to claim 1, wherein in the case where the difference between reference turning torque obtained by multiplying the rate of change by the lateral acceleration and the turning torque is equal to or smaller than a threshold value, it is determined to be in the linear region, and in the case where the difference exceeds the threshold value, it is determined to be in the nonlinear region. ### Claim 6 (depends on 1) The steering control device according to claim 1, wherein in the case where the lateral acceleration increases and the turning torque changes from an increase to a decrease, a shift from the linear region to the nonlinear region is detected. ### Claim 7 (depends on 1) The steering control device according to claim 1, wherein the steering torque of the steering wheel operated by the driver is acquired, and wherein in the case where the steering torque is equal to or larger than a threshold value in the nonlinear region, the turning torque for turning the tires is increased. ### Claim 8 (depends on 7) The steering control device according to claim 7, wherein in the case where the steering torque equal to or larger than the threshold value in the nonlinear region continues for a certain period of time, the reaction force is decreased. ### Claim 9 (depends on 7) The steering control device according to claim 7, wherein the steering angle of the steering wheel operated by the driver and the turning angle of the tires are acquired, wherein a reference turning torque is calculated on the basis of the relationship between the steering angle and the turning angle, and wherein in the case where the steering torque is equal to or larger than the threshold value in the nonlinear region, additional turning torque corresponding to the magnitude of the steering torque is calculated, and a value obtained by adding the additional turning torque to the reference turning torque is output as the turning torque. ### Claim 10 (depends on 1) The steering control device according to claim 1, wherein the steering angular speed of the steering wheel operated by the driver is acquired, and wherein in the case where the steering angular speed exceeds a prescribed threshold value, the rate of increase of the reaction force is limited to a prescribed upper limit value. ### Claim 11 (depends on 1) The steering control device according to claim 1, wherein in the case where the steering wheel and a turning mechanism for turning the tires are not mechanically connected to each other, the reaction force is generated.