Patent ID: 8447491

Claim:
A method for controlling output torque (T eng ) of a propulsion unit in a vehicle powertrain comprising driven wheels drivingly connected to the propulsion unit via a mechanical transmission with a drive shaft, the method comprising: registering a driver torque demand (T d ) for vehicle propulsion; registering a propulsion unit rotational speed (ω e ); controlling the output torque (T eng ) of the propulsion unit to asymptotically follow the driver torque demand (T d ) using a closed-loop linear-quadratic regulator (LQR) based controller having the driver torque demand (T d ) and the propulsion unit rotational speed (ω e ) as input data, in order to minimize oscillations; receiving, via the closed-loop LQR based controller, a full state vector information ({circumflex over (x)}) from a state observer based on at least the propulsion unit rotational speed (ω e ); generating, via the closed-loop LQR based controller, a controller torque demand (T f ) used for the controlling of the output torque (T eng ) of the propulsion unit based on the driver torque demand (T d ) and the full state vector information ({circumflex over (x)}), and wherein the controlling of the output torque (T eng ) of the propulsion unit is realized by regulating at least the following three performance index components of the controller to zero: a time derivative of a drive shaft torque ({dot over (T)} shaft ) of the drive shaft; an integrated difference (x u ) between the driver torque demand (T d ) and the controller torque demand (T f ); and a current difference between the driver torque demand (T d ) and the controller torque demand (T f ).