# US 9,751,558 B2 · Handwheel obstruction detection and inertia compensation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,751,558 B2 - Document ID: US9751558B2 - Status: Granted - Kind: B2 - Application number: 14/667,855 - Filed: 2015-03-25 - Published: 2016-09-29 - Granted: 2017-09-05 - Earliest claimed: 2015-03-25 - Assignees: Ford Global Technologies, LLC - Applicants: Ford Global Technologies, LLC - Inventors: Erick Michael Lavoie; Darrel Alan Recker; Michael Richard Johnson - Web page: https://patentgrep.com/patent/US9751558B2 ## CPC - B62D 13/06: for backing a normally drawn trailer - B62D 1/04: Hand wheels - B62D 5/0463: {calculating assisting torque from the motor based on driver input} - B62D 5/0481: {monitoring the steering system, e.g. failures} - B62D 6/10: characterised by means for sensing {or determining} torque - B62D 15/0285: {Parking performed automatically} - B62D 5/00: Power-assisted or power-driven steering (for non-deflectable wheels B62D11/00; fluid-pressure servomotors in general F15B) - 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 system includes a first sensor sensing a pinion angle of a handwheel and a second sensor sensing a torsion bar windup angle. An autonomous steering module generates a steering command having an input torque signal. A steering angle controller is configured to determine a filtered handwheel acceleration based on the pinion angle and the windup angle. The steering angle controller also determines an offset torque based on the filtered handwheel acceleration. Further, the steering angle controller applies the offset torque to the input torque signal to define a refined torque signal that compensates for inertia and off-center mass of the handwheel. ## Claims ### Claim 1 A vehicle steering system, comprising: a first sensor sensing a pinion angle of a handwheel; a second sensor sensing a torsion bar windup angle; an autonomous steering module generating a steering command having an input torque signal; and a steering angle controller configured to determine a filtered handwheel acceleration based on the pinion angle and the torsion bar windup angle, determine an offset torque based on the filtered handwheel acceleration, and apply the offset torque to the input torque signal to define a refined torque signal that compensates for inertia and off center mass of the handwheel. ### Claim 2 (depends on 1) The vehicle steering system of claim 1, wherein a high torque value associated with a sudden change in direction of the pinion angle is reduced in the refined torque signal to prevent the refined torque signal from errantly exceeding a torque threshold, and wherein the torque threshold is configured to be exceeded when an object is obstructing rotation of the handwheel. ### Claim 3 (depends on 1) The vehicle steering system of claim 1, wherein the steering angle controller autonomously operates the pinion angle based on the refined torque signal. ### Claim 4 (depends on 3) The vehicle steering system of claim 3, wherein the steering angle controller stops autonomous control of the pinion angle when the refined torque signal exceeds a threshold torque. ### Claim 5 (depends on 1) The vehicle steering system of claim 1, wherein the refined torque signal is passed through a low-pass filter prior to operating the pinion angle with the refined torque signal. ### Claim 6 (depends on 1) The vehicle steering system of claim 1, wherein the filtered handwheel acceleration is filtered with a high-pass filter after combining the pinion angle and the windup angle. ### Claim 7 A vehicle steering system, comprising: a sensor sensing a handwheel angle based on a sensed pinion angle and a sensed torsion bar windup angle; an autonomous steering module generating an input torque signal; and a steering angle controller determining a handwheel acceleration based on the handwheel angle, determining an offset torque based on the handwheel acceleration, and generating a compensated torque signal based on the offset torque and the input torque signal. ### Claim 8 (depends on 7) The vehicle steering system of claim 7, wherein the sensor includes a first sensor sensing the pinion angle and a second sensor sensing the torsion bar windup angle. ### Claim 9 (depends on 7) The vehicle steering system of claim 7, wherein the autonomous steering module includes a trailer backup assist controller for generating a steering command for guiding a trailer in reverse, the steering command having the input torque signal. ### Claim 10 (depends on 7) The vehicle steering system of claim 7, wherein the compensated torque signal is configured to compensate for inertia and off-center mass of a handwheel. ### Claim 11 (depends on 8) The vehicle steering system of claim 8, wherein a high torque value associated with a sudden change in direction of the pinion angle is reduced in the compensated torque signal to prevent the compensated torque signal from errantly exceeding a torque threshold. ### Claim 12 (depends on 8) The vehicle steering system of claim 8, wherein the steering angle controller autonomously operates the pinion angle based on the compensated torque signal and stops autonomous control of the pinion angle when the compensated torque signal exceeds a torque threshold. ### Claim 13 (depends on 7) The vehicle steering system of claim 7, wherein the compensated torque signal is passed through a low-pass filter prior to operating the handwheel angle with the compensated torque signal, and wherein the handwheel acceleration is filtered with a high-pass filter. ### Claim 14 A method, comprising: sensing an angle of a handwheel based on a sensed pinion angle and a sensed torsion bar windup angle; generating a steering command having an input torque signal; determining a handwheel acceleration based on the angle; determining an offset torque based on the handwheel acceleration; and generating a compensated torque signal based on the offset torque and the input torque signal to compensate for inertia and off-center mass of the handwheel. ### Claim 15 (depends on 14) The method of claim 14, wherein sensing the angle of the handwheel includes sensing the pinion angle and sensing the torsion bar windup angle, and wherein the angle of the handwheel is based on the pinion angle combined with the torsion bar windup angle. ### Claim 16 (depends on 14) The method of claim 14, further comprising: generating the steering command for a vehicle guiding a trailer in reverse; and autonomously operating the angle of the handwheel based on the compensated torque signal. ### Claim 17 (depends on 14) The method of claim 14, wherein the compensated torque signal is passed through a low-pass, and wherein the handwheel acceleration is filtered with a high-pass filter. ### Claim 18 (depends on 14) The method of claim 14, wherein a high torque value associated with a sudden change in direction of a pinion angle is reduced in the compensated torque signal to prevent the compensate torque signal from errantly exceeding a torque threshold. ### Claim 19 (depends on 14) The method of claim 14, further comprising: autonomously operating a handwheel angle based on the compensated torque signal and ceasing autonomous operation of the handwheel angle when the compensated torque signal exceeds a threshold torque. ### Claim 20 (depends on 19) The method of claim 19, wherein the threshold torque value is configured to be exceeded when an object is obstructing a predicted change to the handwheel angle.