Trailer backup aid speed limiting via braking

• US 9,840,240 B2
• Filed: 09/11/2015
• Issued: 12/12/2017
• Est. Priority Date: 04/09/2015
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Trombley, Roger Arnold, Lavoie, Erick Michael, Yu, Hai
• Primary Examiner(s): Shaawat, Mussa A
• Assistant Examiner(s): ODEH, NADEEM N
• Application Number:
  US14/851,895
• Publication Number:
  US 20160297411A1
• Time in Patent Office: 823 Days
• Field of Search: 701 48
• CPC Class Codes: B60T 13/662 characterised by specified functions of the control system components
• CPC Class Codes: B60T 2201/04 Hill descent control
• CPC Class Codes: B60T 2230/08 Driving in reverse
• CPC Class Codes: B60T 7/20 specially for trailers, e.g. in case of uncoupling of or overrunning by trailer inertia-actuated overrun brakes B60T13/08
• CPC Class Codes: B60T 8/1708 for lorries or tractor-trailer combinations
• CPC Class Codes: B60T 8/245 Longitudinal vehicle inclination
• CPC Class Codes: B60W 2300/14 Tractor-trailers, i.e. combinations of a towing vehicle and one or more towed vehicles, e.g. caravans; Road trains
• CPC Class Codes: B60W 2510/0604 Throttle position
• CPC Class Codes: B60W 2520/22 Articulation angle, e.g. between tractor and trailer
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2552/15 Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 2710/18 Braking system
• CPC Class Codes: B60W 2710/20 Steering systems
• CPC Class Codes: B60W 30/146 Speed limiting
• CPC Class Codes: B60W 40/076 Slope angle of the road

Abstract

A trailer backup assist system for a vehicle reversing a trailer is provided herein. The system includes a brake system and a steering system of the vehicle. A controller is configured to output a brake torque request to the brake system and a steering command to the steering system, wherein the brake torque request and the steering command are each based at least in part on a trailer mass.

Claims

1. A trailer backup assist system for a vehicle reversing a trailer, comprising:

a brake system; and

a controller configured to;

generate a speed signal error by comparing a stored vehicle target speed with a vehicle speed input received from a speed detector;

generate a brake torque request based on the speed signal error and a trailer mass; and

output the brake torque request to the brake system;

wherein the controller is further configured to calculate an estimated road grade of a surface on which the trailer is positioned;

wherein the estimated road grade is determined by estimating a first total mass of the vehicle and trailer and comparing the first total mass to a second total mass of the vehicle and trailer that is estimated after movement of the trailer in a reverse direction from a first position to a second position;

wherein the estimated road grade is based on the difference between the first and second total mass; and

wherein the brake torque request is further based on the estimated road grade and a throttle application signal from a throttle sensor.

2. The trailer backup assist system of claim 1, wherein the trailer mass is obtained via user input.

3. The trailer backup assist system of claim 1, wherein the trailer mass is obtained via sensors disposed on the trailer.

4. The trailer backup assist system of claim 1, wherein the trailer mass is estimated based on trailer dynamics while the trailer is in motion.

5. The trailer backup assist system of claim 1, wherein the controller comprises a proportional-integral-derivative controller configured to receive the speed signal error and generate the brake torque request, and wherein the proportional-integral-derivative controller is tuned for different trailer masses and the gains of the proportional-integral-derivative controller are determined using lookup tables.

6. The trailer backup assist system of claim 1, wherein the controller is further configured to output a steering command to a steering system of the vehicle, wherein the steering command is based at least in part on the trailer mass.

7. A trailer backup assist system for a vehicle reversing a trailer, comprising:

a brake system of the vehicle; and

a controller configured to;

generate a speed signal error from a stored vehicle target speed and a vehicle speed input received from a speed detector;

generate an initial brake torque request signal from the speed signal error;

generate a brake torque request from the initial brake torque request signal and a feed forward gain that is based on trailer mass and supplied from a trailer mass estimation module; and

output the brake torque request to the brake system;

wherein the controller is further configured to calculate an estimated road grade of a surface on which the trailer is positioned;

wherein the estimated road grade is determined by estimating a first total mass of the vehicle and trailer and comparing the first total mass to a second total mass of the vehicle and trailer that is estimated after movement of the trailer in a reverse direction from a first position to a second position;

wherein the estimated road grade is based on the difference between the first and second total mass; and

wherein the brake torque request is further based on the estimated road grade and a throttle application signal from a throttle sensor.

8. The trailer backup assist system of claim 7, wherein the trailer mass is obtained via at least one of user input and sensors disposed on the trailer.

9. The trailer backup assist system of claim 7, wherein the trailer mass is estimated based on trailer dynamics while the trailer is in motion.

10. A method of controlling the speed of a vehicle towing a trailer, comprising the steps of:

receiving a vehicle speed input from a speed detector;

generating a speed signal error from a stored vehicle target speed and the vehicle speed input;

generating an initial brake torque request signal from the speed signal error;

generating a brake torque request from the initial brake torque request signal, a feed forward gain that is based on trailer mass and supplied from a trailer mass estimation module, an estimated road grade of a surface on which the trailer is positioned, and a throttle application signal from a throttle sensor; and

outputting the brake torque request to a brake system of the vehicle;

wherein the estimated road grade is determined by estimating a first total mass of the vehicle and trailer and comparing the first total mass to a second total mass of the vehicle and trailer that is estimated after movement of the trailer in a reverse direction from a first position to a second position; and

wherein the estimated road grade is based on the difference between the first and second total mass.

11. The method of claim 10, wherein the trailer mass is obtained via at least one of user input and sensors disposed on the trailer.

12. The method of claim 10, wherein the trailer mass is estimated based on trailer dynamics while the trailer is in motion.

13. The method of claim 10, wherein the initial brake torque request signal is generated by a proportional-integral-derivative controller using the speed signal error as input.

14. The method of claim 10, further comprising the step of outputting a steering command to a steering system of the vehicle, wherein the steering command is based on the trailer mass, a hitch angle, and a kinematic relationship between the vehicle and the trailer.