Constrained filtering approach for estimation of clutch torque in a two mass system such as a hybrid powertrain

A clutch torque estimation and control method for hybrid powertrain of a vehicle, the method comprising:

• monitoring, by a control system of the vehicle and using a set of sensors of the vehicle, a set of operating parameters of the hybrid powertrain, wherein the hybrid powertrain includes a disconnect clutch configured to connect/disconnect two different torque generating systems;
• detecting, by the control system, a mode transition of the hybrid powertrain that involves a state change of the disconnect clutch;
• and
• in response to detecting the mode transition:
• initializing, by the control system, a Kalman filter based on a state space model for dynamics of the disconnect clutch;
• utilizing, by the control system, the Kalman filter to predict estimated speeds and torques for the state change of the disconnect clutch;
• determining, by the control system, a set of constraints for the state change of the disconnect clutch based on a sign of a slip speed across the disconnect clutch;
• applying, by the control system, the set of constraints to the predicted estimated speeds and torques to obtain final estimated speeds and torques for the state change of the disconnect clutch;
• and
• controlling, by the control system, the disconnect clutch based on the final estimated speeds and torques to improve the mode transition of the hybrid powertrain.