# US 11,440,551 B2 · Automatic crab steering on side hills > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,440,551 B2 - Document ID: US11440551B2 - Status: Granted - Kind: B2 - Application number: 16/560,475 - Filed: 2019-09-04 - Published: 2021-03-04 - Granted: 2022-09-13 - Earliest claimed: 2019-09-04 - Assignees: Deere & Company - Applicants: Deere & Company - Inventors: Scott A. Hudson; Jeffrey M. Tott; Edwin R. Kreis; Dennis A. Bowman - Web page: https://patentgrep.com/patent/US11440551B2 ## CPC - B60W 30/18172: {Preventing, or responsive to skidding of wheels} - B62D 12/00: Steering specially adapted for vehicles operating in tandem or having pivotally connected frames (steering endless tracks or the like B62D11/00; steering specially adapted for trailers B62D13/00) - B62D 6/00: Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits (means for initiating a change in direction B62D1/00; steering valves B62D5/06; combined with means for inclining the vehicle body or wheels on bends B62D9/00) - B62D 7/026: {characterised by comprising more than one bogie, e.g. situated in more than one plane transversal to the longitudinal centre line of the vehicle} - B62D 7/14: the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering - B62D 11/20: Endless-track steering having pivoted bogie carrying track (B62D11/02 takes precedence) - B62D 21/186: {for building site vehicles or multi-purpose tractors (tracked vehicles B62D55/10; tractors in general B62D49/00; building site vehicles in general E02F; lift-trucks B66F)} - B60W 2300/152: Tractors - B60W 2520/10: Longitudinal speed - B60W 2520/125: Lateral acceleration - B60W 2520/14: Yaw - B60W 2520/18: Roll - B60W 2520/26: Wheel slip - B60W 2710/20: Steering systems - B62D 7/1509: {with different steering modes, e.g. crab-steering, or steering specially adapted for reversing of the vehicle} - B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT - 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 Steering a vehicle in an electronic steering mode of operation that includes a front axle steering system, a rear axle steering system, one or more vehicle environment sensors, and a controller operatively coupled with the front axle steering system, the rear axle steering system, and the vehicle environment sensors. Commanding the vehicle to operate at a desired vehicle speed, detecting a lateral force acting on the vehicle in response to input from the vehicle environment sensors, and determining an actual lateral acceleration of the vehicle and a predicted lateral acceleration of the vehicle from the desired vehicle speed. Determining a lateral acceleration error by comparing the predicted lateral acceleration to the actual lateral acceleration, and determining if the lateral acceleration error exceeds a lateral acceleration limit, then turning both of the front axle steering system and the rear axle steering system to a crab steering correction angle. ## Claims ### Claim 1 A system comprising: a vehicle including a front axle steering system, a rear axle steering system, one or more vehicle environment sensors, and a controller operatively coupled with the front axle steering system, the rear axle steering system, and the one or more vehicle environment sensors, wherein the controller is configured to: operate the vehicle in an electronic steering mode of operation at a desired vehicle speed; detect presence of a lateral force on the vehicle in response to input from the one or more vehicle environment sensors; in response to detection of the lateral force on the vehicle and in response to the desired vehicle speed, determine an actual lateral acceleration of the vehicle and a predicted lateral acceleration of the vehicle; determine a lateral acceleration error by comparing the predicted lateral acceleration to the actual lateral acceleration; and in response to the determination of the lateral acceleration error, determine if the lateral acceleration error exceeds a lateral acceleration limit, then compensate for the lateral force acting on the vehicle by turning both of the front axle steering system and the rear axle steering system to a crab steering correction angle. ### Claim 2 (depends on 1) The system of claim 1, wherein the crab steering correction angle is adjusted by an operator correction factor. ### Claim 3 (depends on 1) The system of claim 1, wherein the crab steering correction angle includes a front axle steering angle and a rear axle steering angle, the front axle steering system configured to adjust to the front axle steering angle and the rear axle steering system configured to adjust to the rear axle steering angle. ### Claim 4 (depends on 3) The system of claim 3, wherein the front axle steering angle is different from the rear axle steering angle. ### Claim 5 (depends on 1) The system of claim 1, wherein the vehicle includes an articulated steering system between the rear and the front axle steering systems configured to laterally offset the rear axle steering system from the front axle steering system. ### Claim 6 (depends on 1) The system of claim 1, wherein the one or more sensors measure a yaw rate and an actual vehicle speed. ### Claim 7 (depends on 1) The system of claim 1, wherein the one or more sensors include a lateral accelerometer. ### Claim 8 (depends on 1) The system of claim 1, wherein the one or more sensors measure a vehicle roll angle; and adjusting the crab steering correction angle based on the vehicle roll angle. ### Claim 9 (depends on 1) The system of claim 1, wherein the front axle steering system includes at least two wheels, the rear axle steering system includes at least two wheels, wherein the one or more sensors measures a wheel slip condition of each of the wheels of the front axle steering system and the rear axle steering system; and adjusting the crab steering correction angle based on the wheel slip condition being satisfied for any of the wheels. ### Claim 10 (depends on 1) The system of claim 1, wherein the crab steering correction angle is between 0 and 15 degrees as measured relative to a longitudinal axis of each of the front axle steering system and the rear axle steering system. ### Claim 11 A method of steering a vehicle, comprising: operating the vehicle in an electronic steering mode of operation wherein the vehicle includes a front axle steering system, a rear axle steering system, one or more vehicle environment sensors, and a controller operatively coupled with the front axle steering system, the rear axle steering system, and the one or more vehicle environment sensors; commanding the vehicle to operate at a desired vehicle speed; detecting a lateral force acting on the vehicle in response to input from the one or more vehicle environment sensors; in response to detecting the lateral force and the desired vehicle speed, determining an actual lateral acceleration of the vehicle and a predicted lateral acceleration of the vehicle from the desired vehicle speed; determining a lateral acceleration error by comparing the predicted lateral acceleration to the actual lateral acceleration; and in response to the determination of the lateral acceleration error, determining if the lateral acceleration error exceeds a lateral acceleration limit, then turning both of the front axle steering system and the rear axle steering system to a crab steering correction angle. ### Claim 12 (depends on 11) The method of claim 11, wherein the crab steering correction angle is adjusted by an operator correction factor. ### Claim 13 (depends on 11) The method of claim 11, wherein the crab steering correction angle includes a front axle steering angle and a rear axle steering angle; adjusting the front axle steering system to the front axle steering angle; and adjusting the rear axle steering system to the rear axle steering angle. ### Claim 14 (depends on 13) The method of claim 13, wherein the front axle steering angle is different from the rear axle steering angle. ### Claim 15 (depends on 11) The method of claim 11, wherein the vehicle includes an articulated joint between the rear and the front axle steering systems; and offsetting laterally the rear axle steering system from the front axle steering system. ### Claim 16 (depends on 11) The method of claim 11, further comprising: measuring a yaw rate and an actual vehicle speed with the one or more sensors; and determining the actual lateral acceleration with the yaw rate and actual vehicle speed. ### Claim 17 (depends on 11) The method of claim 11, wherein the one or more sensors include a lateral accelerometer for measuring the actual lateral acceleration. ### Claim 18 (depends on 11) The method of claim 11, wherein the one or more sensors measure a vehicle roll angle; and adjusting the crab steering correction angle based on the vehicle roll angle. ### Claim 19 (depends on 11) The method of claim 11, wherein the front axle steering system includes at least two wheels, the rear axle steering system includes at least two wheels, measuring a wheel slip condition of each of the wheels of the front axle steering system and the rear axle steering system with one or more sensors; and adjusting the crab steering correction angle based on the wheel slip condition being satisfied for any of the wheels. ### Claim 20 (depends on 11) The method of claim 11, wherein the crab steering correction angle is between 0 and 15 degrees as measured relative to a longitudinal axis of each of the front axle steering system and the rear axle steering system.