# US 11,440,585 B2 · Speed control for motor vehicles > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,440,585 B2 - Document ID: US11440585B2 - Status: Granted - Kind: B2 - Application number: 16/793,177 - Filed: 2020-02-18 - Published: 2020-06-25 - Granted: 2022-09-13 - Earliest claimed: 2015-10-19 - Assignees: Ford Global Technologies, LLC - Applicants: Ford Global Technologies, LLC - Inventors: Erick Michael Lavoie; Donald Jacob Mattern; Joseph M. Raad - Web page: https://patentgrep.com/patent/US11440585B2 ## CPC - B62D 15/027: {Parking aids, e.g. instruction means} - B62D 13/06: for backing a normally drawn trailer - 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 trailer backup assist system is provided herein. The trailer backup assist system includes a hitch angle sensor configured to determine a hitch angle between a vehicle and a trailer attached thereto. An input device is configured to accept an input command corresponding to a trailer path command curvature. A controller is configured to determine a vehicle threshold speed limit by determining a first vehicle speed limit based on the hitch angle and a second speed limit based on the command curvature. The controller generates a command to limit vehicle speed in a reverse direction below the threshold speed limit. ## Claims ### Claim 1 A trailer backup assist system, comprising: a hitch angle sensor configured to determine a hitch angle between a vehicle and a trailer attached thereto; an input device configured to accept an input command corresponding to a trailer path command curvature; and a controller configured to determine a vehicle threshold speed limit by determining a first vehicle speed limit based on the hitch angle and a second vehicle speed limit based on the command curvature, wherein the controller generates a command to limit vehicle speed in a reverse direction below the threshold speed limit and the vehicle threshold speed limit is set to the higher of the first and second vehicle speed limits when a magnitude of an input command is decreasing and the vehicle threshold speed limit is set to the lower of the first and second vehicle speed limits when a magnitude of input command is increasing. ### Claim 2 (depends on 1) The trailer backup assist system of claim 1, wherein the command controls at least one of a brake system, an engine torque, and a transmission gear selection to thereby control the vehicle speed in the reverse direction. ### Claim 3 (depends on 2) The trailer backup assist system of claim 2, wherein the brake system is a vehicle brake system. ### Claim 4 (depends on 1) The trailer backup assist system of claim 1, wherein the vehicle threshold speed limit is the higher of the first and second vehicle speed limits when a magnitude of hitch angle is decreasing and the desired trailer path command curvature is less than an instantaneous trailer path curvature. ### Claim 5 (depends on 1) The trailer backup assist system of claim 1, wherein the input device includes a rotatable knob configured to be mounted in a vehicle interior. ### Claim 6 A method of controlling the speed of a motor vehicle, the method comprising: determining a hitch angle between a vehicle and a trailer attached to the vehicle; determining a trailer curvature command based on an input device; calculating a first vehicle speed limit based on the hitch angle; calculating a second speed limit based on the trailer path curvature command; determining a threshold speed limit based on the first and second speed limits; and limiting the speed of the vehicle to the threshold speed, wherein a controller sets the vehicle threshold speed limit at the higher of the first and second speed limits when an absolute value of the hitch angle is decreasing and a trailer curvature command magnitude is also decreasing. ### Claim 7 (depends on 6) The method of claim 6, wherein a vehicle is maintained below the threshold speed limit by controlling at least one of a brake system, an engine torque, and a transmission gear selection to move the trailer along a desired trailer curvature path that is within an acceptable error criteria. ### Claim 8 (depends on 6) The method of claim 6, wherein the input device receives an input as an input magnitude that is correlated to a corresponding trailer curvature path based on values stored in a look-up table. ### Claim 9 (depends on 6) The method of claim 6, wherein the input device is biased towards a neutral position.