Closed-loop control for trailer sway mitigation

A system for controlling a towing vehicle connected to a vehicle trailer, the system comprising:

• a plurality of sensors positioned on the towing vehicle configured to sense a set of vehicle conditions indicative of movements exhibited by the towing vehicle caused by the vehicle trailer, the set of vehicle conditions including a plurality of condition values each sensed by a different one of the plurality of vehicle sensors;
• a comparator configured to determine a plurality of differences between the set of vehicle conditions and a set of vehicle targets, the set of vehicle targets including a plurality of target values each corresponding to a different one of the plurality of vehicle sensors;
• a trend module configured to determine a trend of the plurality of differences;
• a symmetric control system configured to determine a symmetric force to apply to the vehicle based at least in part on the set of vehicle targets and the set of vehicle conditions;
• an asymmetric control system configured to determine an asymmetric force to apply to the vehicle based at least in part on the set of vehicle targets and the set of vehicle conditions;
• a switch configured to select between the symmetric control system and the asymmetric control system based on the trend;
• and
• a vehicle system configured to be actuated by the selected control system to apply the symmetric force or the asymmetric force to the towing vehicle.

A method of controlling a towing vehicle connected to a vehicle trailer, the method comprising:

• determining a set of vehicle targets for the towing vehicle, the set of vehicle targets including a plurality of target values each corresponding to a different one of a plurality of vehicle sensors positioned on the towing vehicle;
• sensing a set of vehicle conditions indicative of movements exhibited by the towing vehicle caused by the vehicle trailer, the set of vehicle conditions including a plurality of condition values each sensed by a different one of the plurality of vehicle sensors;
• determining a plurality of differences between the set of vehicle targets and the set of vehicle conditions;
• determining a trend of the plurality of differences;
• determining a switching signal based on the trend;
• and
• selectively applying either symmetric braking or asymmetric braking based on the switching signal to decrease the plurality of differences.