Torque modulation to linearize tire slip characteristics

A control system for a driveline of a vehicle including a plurality of wheels, the control system comprising:

• at least one sensor for generating at least one sensor input for the vehicle;
• at least one vehicle controller for generating at least one driver input for the vehicle:
• a plurality of modules disposed in electrical communication with said at least one sensor and said at least one vehicle controller to receive said at least one sensor input and said at leats one driver input
• said plurality of modules including a base torque calculation module configured to determine and output a wheel torque command signal;
• said plurality of modules including a torque modulation module disposed in electrical communication with said base torque calculation module and configured to receive said wheel torque command signal and generate a periodic torque modulation signal based on said wheel torque command signal and said at least one sensor input, wherein said periodic torque modulation signal has a modulation amplitude and a modulation frequency;
• said plurality of modules including an adder module disposed in electrical communication with said base torque calculation module and said torque modulation module and configured to add said periodic torque modulation signal received from said torque modulation module to said wheel torque command signal from said base torque calculation module and generate a modulated wheel torque command signal to linearize a tire characteristic of the plurality of tires of the vehicle;
• and
• said plurality of modules including a slip and force determining module disposed in electric communication with said base torque calculation module and said torque modulation module and and configured to determine a plurality of tire parameters.

A computer program including program instructions tangibly stored on a computer-readable medium and operable when executed to cause a processor to perform a method of operating a control system for a driveline of a vehicle comprising the steps of:

• communicating with a plurality of vehicle controllers using a base torque calculation module;
• receiving a plurality of sensor inputs using the base torque calculation module;
• determining a plurality of tire parameters of a plurality of tires of the vehicle using a slip and force determining module;
• determining a wheel torque command signal based on the communication with the plurality of vehicle controllers and the plurality of sensor inputs and the plurality of tire parameters using the base torque calculation module;
• outputting the wheel torque command signal using the base torque calculation module;
• generating a periodic torque modulation signal based on the wheel torque command signal and the plurality of tire parameters using a torque modulation module;
• adding the periodic torque modulation signal to the wheel torque command signal from the base torque calculation module using an adder module;
• outputting a modulated wheel torque command signal to a wheel torque generator driving the plurality of tires of the vehicle using the adder module;
• and
• linearizing a tire characteristic of the plurality of tires in response to the modulated wheel torque command signal.