# US 12,179,856 B2 · Methods and apparatus to determine loads encountered by a steering rack > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,179,856 B2 - Document ID: US12179856B2 - Status: Granted - Kind: B2 - Application number: 18/518,144 - Filed: 2023-11-22 - Published: 2024-03-14 - Granted: 2024-12-31 - Earliest claimed: 2021-03-19 - Assignees: Ford Global Technologies, LLC - Applicants: Ford Global Technologies, LLC - Inventors: Joseph Washnock - Web page: https://patentgrep.com/patent/US12179856B2 ## CPC - B62D 5/0481: {monitoring the steering system, e.g. failures} - B62D 3/126: {characterised by the rack} - B62D 5/0406: {including housing for electronic control unit} - B62D 5/0427: {the axes being coaxial} - B62D 5/0448: {Ball nuts} - 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 Methods and apparatus to determine rack force are disclosed. An example apparatus includes a rack to couple to a steering knuckle of a vehicle, a ball nut engaged with the rack, a first ring gear coupled to the ball nut, a first pinion fixed to a motor, the first pinion engaged with the first ring gear, the motor to rotate the ball nut to move the rack, a motor encoder to detect a rotation of the first pinion, a second ring gear coupled to the ball nut, and a sensor fixed to a second pinion, the second pinion engaged with the second ring gear, the second pinion to rotate as the second ring gear rotates, the sensor to detect a rotation of the second pinion, the rotation of the second pinion and the rotation of the first pinion corresponding to a force on the rack. ## Claims ### Claim 1 An apparatus comprising: a rotary encoder to generate a first signal based on a position of a motor shaft that includes a first pinion engaged with a first ring gear; a sensor to generate a second signal based on a rotation of a second pinion that is engaged with a second ring gear; machine readable instructions; and processor circuitry configured to execute or execute the machine readable instructions to determine a load on a steering rack of a vehicle based on the first signal and the second signal. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the processor circuitry is to control a torque on a steering wheel based on the load. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the processor circuitry is to: determine a first position of the steering rack based on the first signal; determine a second position of the steering rack based on the second signal; when the first position is different from the second position, determine the steering rack has a non-zero load; and when the first position matches the second position, determine the load is zero. ### Claim 4 (depends on 3) The apparatus of claim 3, wherein, when the first position is different from the second position, the processor circuitry is to determine a value of the non-zero load based on a difference between the first position and the second position. ### Claim 5 (depends on 4) The apparatus of claim 4, wherein, when the first position is different from the second position, the processor circuitry is to determine the value of the non-zero load based on a spring rate of a spring that resists linear movement of the first ring gear and the second ring gear. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the processor circuitry is to determine a steering angle implemented by wheels of the vehicle based on at least one of the first signal or the second signal. ### Claim 7 (depends on 6) The apparatus of claim 6, wherein the processor circuitry is to: determine whether the steering angle matches a target steering angle associated with a position of a steering wheel; and when the steering angle is different from the target steering angle, control an output of a motor to adjust the steering angle based on a difference between the steering angle and the target steering angle. ### Claim 8 A non-transitory machine readable storage medium comprising instructions to cause processor circuitry to at least determine a load encountered by a steering rack of a vehicle based on (i) a first signal corresponding to a position of a motor shaft and (ii) a second signal corresponding to a rotation of a pinion separate from the motor shaft. ### Claim 9 (depends on 8) The non-transitory machine readable storage medium of claim 8, wherein the instructions cause the processor circuitry to control a torque on a steering wheel based on the load. ### Claim 10 (depends on 8) The non-transitory machine readable storage medium of claim 8, wherein the instructions cause the processor circuitry to: determine a first position of the steering rack based on the first signal; determine a second position of the steering rack based on the second signal; when the first position is different from the second position, determine the steering rack has a non-zero load; and when the first position matches the second position, determine the load is zero. ### Claim 11 (depends on 10) The non-transitory machine readable storage medium of claim 10, wherein, when the first position is different from the second position, the instructions cause the processor circuitry to determine a value of the non-zero load based on a difference between the first position and the second position. ### Claim 12 (depends on 11) The non-transitory machine readable storage medium of claim 11, wherein, when the first position is different from the second position, the instructions cause the processor circuitry to determine the value of the non-zero load based on a spring rate of a spring that resists linear movement of a geared thrust bearing engaged with the motor shaft and the pinion. ### Claim 13 (depends on 8) The non-transitory machine readable storage medium of claim 8, wherein the instructions cause the processor circuitry to determine a steering angle implemented by wheels of the vehicle based on at least one of the first signal or the second signal. ### Claim 14 (depends on 13) The non-transitory machine readable storage medium of claim 13, wherein the instructions cause the processor circuitry to: determine whether the steering angle matches a target steering angle associated with a position of a steering wheel; and when the steering angle is different from the target steering angle, control an output of a motor to adjust the steering angle based on a difference between the steering angle and the target steering angle. ### Claim 15 A method comprising: determining a load encountered by a steering rack of a vehicle based on (i) a first signal corresponding to a position of a motor shaft and (ii) a second signal corresponding to a rotation of a pinion separate from the motor shaft. ### Claim 16 (depends on 15) The method of claim 15, further including controlling a torque on a steering wheel based on the load. ### Claim 17 (depends on 15) The method of claim 15, further including: determining a first position of the steering rack based on the first signal; determining a second position of the steering rack based on the second signal; when the first position is different from the second position, determining the steering rack has a non-zero load; and when the first position matches the second position, determining the load is zero. ### Claim 18 (depends on 17) The method of claim 17, further including, when the first position is different from the second position, determining a value of the non-zero load based on a difference between the first position and the second position. ### Claim 19 (depends on 18) The method of claim 18, further including, when the first position is different from the second position, determining the value of the non-zero load based on a spring rate of a spring that resists linear movement of a geared thrust bearing engaged with the motor shaft and the pinion. ### Claim 20 (depends on 15) The method of claim 15, further including: determining a steering angle implemented by wheels of the vehicle based on at least one of the first signal or the second signal; determining whether the steering angle matches a target steering angle associated with a position of a steering wheel; and when the steering angle is different from the target steering angle, adjusting an output of a motor to cause an adjustment to the steering angle based on a difference between the steering angle and the target steering angle.