Method to adjust adaptive cruise control with detection of aftermarket trailer brake controller

1 . A motor vehicle comprising:

a vehicle control system;

a speed control system that is configured to increase a speed of the vehicle and to provide negative vehicle wheel torque to reduce the speed of the vehicle when the speed control system receives a speed reduction command;

the vehicle control system including an adaptive cruise control that is configured to determine that the vehicle is towing a trailer having an active speed reduction system whereby the trailer generates negative trailer wheel torque in addition to negative vehicle wheel torque, and to operate the speed control system to compensate for the negative trailer wheel torque and provide a desired vehicle rate of reduction in speed when the vehicle is towing a trailer having an active speed reduction system, wherein the adaptive cruise control is configured to generate speed reduction commands to the speed control system of the vehicle and/or to the active speed reduction system of the trailer to maintain: 1) a vehicle speed and/or 2) a target following distance between the vehicle and a target vehicle in front of the vehicle, wherein the speed reduction commands are associated with expected rates of reductions in speed of the vehicle;

and wherein the adaptive cruise control is configured to determine an estimated combined mass of the vehicle and trailer;

and wherein the adaptive cruise control is configured to determine the rate of reduction in speed of the vehicle due to the active trailer speed reduction system based, at least in part, on 1) the estimated combined mass of the vehicle and trailer and, 2) measured rate of reduction in speed of the vehicle in response to a speed reduction command;

and wherein the adaptive cruise control is configured to continuously monitor and compare the measured rate of reduction in speed of the vehicle to an expected rate of reduction in speed of the vehicle corresponding to the speed reduction command while the vehicle is towing a trailer having an active speed reduction system, and to continuously adjust speed reduction commands to the vehicle speed control system and/or speed reduction commands to the active speed reduction system of the trailer while the vehicle is towing a trailer having an active speed reduction system if a vehicle rate of reduction in speed does not satisfy predefined criteria, whereby the vehicle control system determines the effects of the negative trailer wheel torque and compensates for negative trailer wheel torque.

2 . The motor vehicle of claim 1 , wherein:

the predefined criteria further comprises a maximum acceptable jerk, wherein jerk is the third derivative of position with respect to time.

3 . The motor vehicle of claim 2 , wherein:

the maximum acceptable jerk comprises a predefined numerical value.

4 . The motor vehicle of claim 1 , wherein:

the adaptive cruise control is configured to utilize a towing mode if the adaptive cruise control determines that a trailer is connected to the vehicle;

and wherein, when in the towing mode, the adaptive cruise control is configured to determine a desired rate of reduction in speed and generate an initial speed reduction command to the speed control system based, at least in part, on the desired rate of reduction in speed, and wherein the adaptive cruise control is configured to determine a difference between a measured rate of reduction in speed resulting from the speed reduction command and the desired rate of reduction in speed while towing a trailer, and to adjust the initial speed reduction command while towing a trailer to provide an adjusted speed reduction command that reduces differences between the measured rate of reduction in speed and the desired rate of reduction in speed.

5 . The motor vehicle of claim 4 , wherein:

the adaptive cruise control is configured to store an adjusted speed reduction command and associate the adjusted speed reduction command with a specific trailer configuration.

6 . The motor vehicle of claim 5 , wherein:

the adaptive cruise control is configured to determine and store a plurality of adjusted speed reduction commands, wherein each adjusted speed reduction command is associated with a specific trailer configuration and vehicle operating condition, and wherein the adaptive cruise control is configured to determine if a trailer being towed has a specific trailer configuration of a stored adjusted speed reduction command, and utilize a selected adjusted speed reduction command and provide an adjusted speed reduction command to the active speed reduction system of the trailer being towed by the motor vehicle.

7 . The motor vehicle of claim 6 , wherein:

the vehicle operating conditions comprise vehicle speed.

8 . The motor vehicle of claim 4 , wherein:

the adaptive cruise control is configured to repeatedly determine, while towing a trailer having an active speed reduction system, a difference between the measured rate of reduction in speed resulting from the speed reduction command and the desired rate of reduction in speed, where in the difference is due to negative trailer wheel torque of the active speed reduction system of the trailer, and to adjust the initial speed reduction command to provide an adjusted speed reduction command that further reduces differences between the measured rate of reduction in speed and the desired rate of reduction in speed, whereby the adaptive cruise control compensates for negative trailer wheel torque of the active speed reduction system of the trailer.

9 . The motor vehicle of claim 1 , wherein:

the controller is configured to reduce a gain of a speed reduction command to the speed control system of the vehicle and/or a speed reduction command to the active speed reduction system of the trailer if the measured rate of reduction in speed associated with the speed reduction command is greater than the expected rate of reduction in speed associated with the speed reduction command.

10 . The motor vehicle of claim 9 , wherein:

the controller is configured to associate a plurality of reduced gains with specific vehicle operating parameters and utilize a selected one of the reduced gains when the specific vehicle operating parameters are present.

11 . The motor vehicle of claim 10 , wherein:

the specific vehicle operating parameters comprise vehicle speed.

12 . A method of controlling a motor vehicle while the motor vehicle is towing a trailer having an active speed reduction system, the method comprising:

actuating cruise control of the vehicle to control a speed control system of the vehicle;

utilizing the vehicle cruise control to provide speed reduction commands to 1) an active speed reduction system of a trailer being towed by the vehicle, and 2) a vehicle speed control system, wherein the speed reduction command is provided while the vehicle is towing a trailer having an active speed reduction system whereby the trailer generates negative trailer wheel torque in addition to a negative vehicle wheel torque of the vehicle, and wherein the speed reduction command corresponds to an expected rate of reduction in speed that would occur if the vehicle was not towing a trailer having an active speed reduction system;

measuring rate of reduction in speed of the vehicle in response to the speed reduction commands to the active speed reduction system of the trailer being towed by the vehicle and to the vehicle speed control system;

determining a difference between measured rate of reduction in speed and the expected rate of reduction in speed corresponding to the speed reduction command; and

utilizing the vehicle cruise control to provide an adjusted speed reduction command that reduces the difference between measured rate of reduction in speed and the expected rate of reduction in speed whereby the adjusted speed reduction command takes into account negative trailer wheel torque due to the active speed reduction system of the trailer.

13 . The method of claim 12 , including:

utilizing a control system of the vehicle to determine rate of reduction in speed due to the negative wheel torque of the active speed reduction system of a trailer that is being towed by the vehicle;

utilizing the control system of the vehicle to adjust a speed reduction command to the vehicle speed control system and a speed reduction command to the active speed reduction system of a trailer that is being towed by the vehicle to compensate for the negative trailer wheel torque.

14 . The method of claim 13 , including:

storing an adjusted speed reduction command and an associated vehicle operating condition; and

causing the vehicle cruise control to utilize the adjusted speed reduction command when the vehicle cruise control determines that the associated vehicle operating condition is present.

15 . The method of claim 14 , wherein:

the associated vehicle operating condition comprises vehicle speed; and including:

storing a plurality of adjusted speed reduction commands, wherein the adjusted speed reduction commands are associated with different vehicle speeds.

16 . The method of claim 12 , including:

providing a trailer input gain control feature that permits a user to adjust a trailer speed reduction gain input to the vehicle cruise control to thereby adjust the rate of reduction in speed requests from the vehicle cruise control, wherein each rate of reduction in speed request corresponds to a torque of the vehicle speed control system that is used to maintain the vehicle at a first speed;

adjusting the trailer gain until an acceptable gain is found at which the vehicle cruise control provides a combined vehicle and trailer rate of reduction in speed that is acceptable to the user;

determining a target ratio corresponding to the acceptable gain, wherein the target ratio comprises a ratio of vehicle wheel torque at the first speed to a requested rate of reduction in speed at the first speed; and

when the vehicle is not operating at the first speed, determine a present ratio of vehicle speed to requested rate of reduction in speed, and adjusting the trailer gain of the vehicle cruise control supplied to the active speed reduction system of the trailer to reduce a difference between the target ratio and the present ratio.

17 . A motor vehicle comprising:

one or more sensors configured to provide sensor data concerning vehicle operating parameters;

a speed control system including a motor that is configured to provide a positive torque that tends to increase a vehicle speed, and a vehicle speed reduction system that is configured to provide a negative vehicle wheel torque that tends to reduce vehicle speed; and

a vehicle control system including an adaptive cruise control that is configured to determine that the vehicle is towing a trailer having an active speed reduction system whereby the trailer generates negative trailer wheel torque in addition to negative vehicle wheel torque, and to generate speed reduction actuation requests to actuate the vehicle speed reduction system and an active speed reduction system of a trailer, wherein the speed reduction actuation requests are based, at least in part, on sensor data from the one or more sensors, and wherein the adaptive cruise control is configured to determine speed reduction effects of the active speed reduction system of the trailer, and to adjust the speed reduction actuation requests to the vehicle speed reduction system and to the active speed reduction system of the trailer to compensate for the negative trailer wheel torque based, at least in part, on the rate of reduction in speed effects of the active speed reduction system of the trailer being towed by the vehicle to reduce variations in rates of reductions in speed caused by the active speed reduction system of the trailer, whereby the vehicle control system determines the effects of the negative trailer wheel torque and compensates for negative trailer wheel torque.

18 . The motor vehicle of claim 17 , wherein:

the motor vehicle is configured to determine if a trailer is operably connected to the motor vehicle;

the adaptive cruise control is configured to generate speed reduction actuation requests corresponding to desired rates of reduction in speed; and

the adaptive cruise control is configured to compare measured rates of reductions in speed resulting from speed reduction actuation requests and adjust new speed reduction actuation requests to reduce differences between the measured rates of reductions in speed and the desired rates of reduction in speed.

19 . The motor vehicle of claim 17 , including:

a trailer operably connected to the motor vehicle, the trailer including an active speed reduction system, and wherein the adaptive cruise control is configured such that, prior to adjustment of the speed reduction actuation requests, the adaptive cruise control causes speed reduction undershoot and/or speed reduction overshoot, wherein the speed reduction overshoot comprises a rate of reduction in speed that is greater than a desired rate of reduction in speed, and the speed reduction undershoot comprises a rate of reduction in speed that is less than a desired rate of reduction in speed;

the adjustments of the speed reduction actuation requests reduce at least one of speed reduction overshoot and speed reduction undershoot.

20 . The motor vehicle of claim 17 , wherein:

the adaptive cruise control is configured to provide a first trailer speed reduction gain at highway speeds, and a second trailer speed reduction gain at low speeds, wherein the first trailer speed reduction gain is greater than the second trailer speed reduction gain whereby the one or more speed reduction devices provide greater torque to slow the trailer at the first trailer gain, and wherein the highway speeds comprise a range of speeds from 55-75 mph, and the low speeds comprise a range of speeds from 5-35 mph.