# US 12,600,403 B2 · Method for checking a steer-by-wire steering system, steering system, and vehicle > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,600,403 B2 - Document ID: US12600403B2 - Status: Granted - Kind: B2 - Application number: 18/578,051 - Filed: 2022-06-08 - Published: 2024-09-26 - Granted: 2026-04-14 - Earliest claimed: 2021-07-15 - Assignees: Schaeffler Technologies AG & Co. KG - Applicants: Schaeffler Technologies AG & Co. KG - Inventors: Habeeb Khan Pathan - Web page: https://patentgrep.com/patent/US12600403B2 ## CPC - B62D 5/0481: {monitoring the steering system, e.g. failures} - B62D 5/001: {Mechanical components or aspects of steer-by-wire systems, not otherwise provided for in this maingroup} - B62D 5/006: {power actuated} - B62D 5/0484: {for reaction to failures, e.g. limp home} - B62D 5/0487: {detecting motor faults (B62D5/0496 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 The disclosure relates to a method for checking a steer-by-wire steering system that includes a steering device, a steering wheel, an actuator configured to exert a torque on the steering wheel, and a control unit configured to correlate a steering wheel angle of the steering wheel with a steering angle of the steering device The method comprises the following steps: i) the actuator is controlled in a closed-loop manner such that the steering wheel angle is correlated with a desired angle and a temporal progression of a state variable of the steering wheel and/or of the actuator is determined; ii) a frequency spectrum of the temporal progression of the state variable is determined and an amplitude of a predefined spectral component of the frequency spectrum is determined; and, iii) a state of the mechanical coupling is classified depending on the amplitude of the spectral component. ## Claims ### Claim 1 A method for checking a steer-by-wire steering system, the steering system comprising a steering device configured to be connected to vehicle wheels, a steering wheel, an actuator configured to exert a torque on the steering wheel via a mechanical coupling, and a control unit configured to adjust a steering wheel angle of the steering wheel to correlate with a steering angle of the steering device via controlling of the actuator, the method comprising: controlling, in a control step, the actuator of the steering wheel so that the steering wheel angle is correlated with a desired angle and a temporal progression of a state variable of the steering wheel is determined; determining, in an analysis step, a frequency spectrum of the temporal progression of the state variable and an amplitude of a predefined spectral component of the frequency spectrum, the predefined spectral component corresponding to a state of the mechanical coupling; and classifying, in a classification step, a state of the mechanical coupling based on the amplitude of the predefined spectral component. ### Claim 2 (depends on 1) The method according to claim 1, wherein in an adjustment step following the classification step, a control parameter for the controlling of the actuator is adjusted based on the amplitude of the predefined spectral component. ### Claim 3 (depends on 1) The method according to claim 1, wherein in a display step following the classification step, a degree of degradation of the mechanical coupling is displayed. ### Claim 4 (depends on 1) The method according to claim 1, wherein the state variable is a torque of the steering wheel. ### Claim 5 (depends on 1) The method according to claim 1, wherein the mechanical coupling is a gear set. ### Claim 6 (depends on 1) The method according to claim 1, wherein the frequency spectrum is determined via a fast Fourier transformation. ### Claim 7 (depends on 2) The method according to claim 2, wherein the controlling of the actuator depends on: i) a difference between the steering wheel angle and the desired angle, and ii) a rate of change over time of the steering wheel angle. ### Claim 8 (depends on 7) The method according to claim 7, wherein the control parameter is a first amplification factor configured to amplify the difference between the steering wheel angle and the desired angle, and, in the adjustment step, a second amplification factor for the controlling of the actuator is adjusted based on the rate of change over time of the steering wheel angle. ### Claim 9 A steer-by-wire steering system comprising: a steering device connected to vehicle wheels, a steering wheel, an actuator configured to exert a torque on the steering wheel via a mechanical coupling, and a control unit configured such that: in a control step, the actuator is controlled by the control unit such that a steering wheel angle correlates with a desired angle, and the control unit is configured to determine a temporal progression of a state variable of at least one of the steering wheel and the actuator, and controlling of the actuator depends on: i) a difference between the steering wheel and the desired angle, and ii) a rate of change over time of the steering wheel angle; in an analysis step, the control unit determines a frequency spectrum of the temporal progression of the state variable and determines an amplitude of a predefined spectral component of the frequency spectrum; and in a classification step, of the control unit classifies a state of the mechanical coupling is carried out based on the amplitude of the predefined spectral component; and in an adjustment step: i) a control parameter for the controlling of the actuator is adjusted based on the amplitude of the predefined spectral component, and the control parameter is a first amplification factor configured to amplify the difference between the steering wheel angle and the desired angle, and ii) a second amplification factor for the controlling of the actuator is adjusted based on the rate of change over time of the steering wheel angle. ### Claim 10 (depends on 9) A vehicle comprising a steer-by-wire steering system according to claim 9. ### Claim 11 (depends on 1) The method according to claim 1, wherein the state variable is an angle of rotation of the steering wheel. ### Claim 12 (depends on 1) The method according to claim 1, wherein the mechanical coupling is a worm gear set. ### Claim 13 A method for checking a steer-by-wire steering system, the steering system comprising a steering device configured to be connected to vehicle wheels, a steering wheel, an actuator configured to exert a torque on the steering wheel via a mechanical coupling, and a control unit configured to adjust a steering wheel angle of the steering wheel to correlate with a steering angle of the steering device via controlling of the actuator, the method comprising: controlling, in a control step, the actuator of the steering wheel so that the steering wheel angle is correlated with a desired angle and a temporal progression of a state variable of the actuator is determined; determining, in an analysis step, a frequency spectrum of the temporal progression of the state variable and an amplitude of a predefined spectral component of the frequency spectrum, the predefined spectral component corresponding to a state of the mechanical coupling; and classifying, in a classification step, a state of the mechanical coupling based on the amplitude of the predefined spectral component. ### Claim 14 (depends on 13) The method according to claim 13, wherein the state variable is a torque of the actuator. ### Claim 15 (depends on 13) The method according to claim 13, wherein the state variable is an angle of rotation of the actuator. ### Claim 16 (depends on 13) The method according to claim 13, wherein the frequency spectrum is determined via a fast Fourier transformation. ### Claim 17 (depends on 13) The method according to claim 13, wherein in an adjustment step following the classification step, a control parameter for the controlling of the actuator is adjusted based on the amplitude of the predefined spectral component. ### Claim 18 (depends on 17) The method according to claim 17, wherein in a display step following the classification step, a degree of degradation of the mechanical coupling is displayed. ### Claim 19 (depends on 17) The method according to claim 17, wherein the controlling of the actuator depends on: i) a difference between the steering wheel angle and the desired angle, and ii) a rate of change over time of the steering wheel angle. ### Claim 20 (depends on 19) The method according to claim 19, wherein the control parameter is a first amplification factor configured to amplify the difference between the steering wheel angle and the desired angle, and, in the adjustment step, a second amplification factor for the controlling of the actuator is adjusted based on the rate of change over time of the steering wheel angle.