Method and apparatus for operating a powertrain system upon detecting a stuck-closed clutch

1. A method for controlling a powertrain system comprising a multi-mode transmission including a plurality of torque-transfer clutches, comprising:

upon detecting one of the torque-transfer clutches is in a stuck-closed condition, employing a closed-loop system to control operation of the multi-mode transmission, comprising:

identifying all presently applied clutches including commanded applied clutches and the stuck-closed clutch;

monitoring adjusted open-loop torque commands and delayed speed states from a previous iteration;

selecting transmission range equations associated with the presently applied clutches, wherein each of the selected transmission range equations correspond to a respective operating range state of the multi-mode transmission;

executing the selected transmission range equations to estimate speed states for the multi-mode transmission based on the adjusted open-loop torque commands and delayed speed states from the previous iteration;

determining torque errors based upon said estimated speed states for the multi-mode transmission; and

adjusting open-loop motor torque commands with the torque errors.

2. The method of claim 1 , wherein determining torque errors based upon said estimated speed states for the multi-mode transmission comprises:

determining reference speed states for the multi-mode transmission based upon the estimated speed states and a plurality of input profiles;

determining speed control errors based upon a difference between the reference speed states and the estimated speed states; and

executing the selected transmission range equations to determine the torque errors based upon the speed control errors.

3. The method of claim 1 , wherein adjusting open-loop motor torque commands with the torque errors comprises adjusting open-loop motor torque commands to control torque outputs of a plurality of torque machines coupled to the multi-mode transmission.

4. A method for controlling a powertrain system comprising a multi-mode transmission including a plurality of torque-transfer clutches and torque machines, comprising:

upon detecting one of the torque-transfer clutches is in a stuck-closed condition, controlling torque outputs of the torque machines accounting for all the presently applied clutches, comprising:

identifying all presently applied clutches including commanded applied clutches and the stuck-closed clutch;

monitoring adjusted open-loop torque commands and delayed speed states from a previous iteration;

selecting transmission range equations associated with the presently applied clutches, wherein each of the selected transmission range equations correspond to a respective operating range state of the multi-mode transmission;

executing the selected transmission range equations to estimate speed states for the multi-mode transmission based on the adjusted open-loop torque commands and delayed speed states from the previous iteration;

determining torque errors based upon said estimated speed states for the multi-mode transmission; and

adjusting open-loop motor torque commands with torque errors.

5. The method of claim 4 , wherein determining torque errors based upon said estimated speed states for the multi-mode transmission comprises:

determining reference speed states for the multi-mode transmission based upon the estimated speed states and a plurality of input speed profiles;

determining speed control errors based upon a difference between the reference speed states and the estimated speed states; and

executing the selected transmission range equations to determine the torque errors based upon the speed control errors.

6. The method of claim 4 , wherein adjusting open-loop motor torque commands with the torque errors comprises adjusting open-loop motor torque commands to control torque outputs of the torque machines.

7. A method for controlling a powertrain system comprising a multi-mode transmission including a plurality of torque-transfer clutches, comprising:

upon detecting one of the torque-transfer clutches is in a stuck-closed condition, employing a closed-loop speed control system to control operation of the multi-mode transmission including accounting for all presently applied clutches, comprising:

identifying all presently applied clutches including commanded applied clutches and the stuck-closed clutch;

monitoring adjusted open-loop torque commands and delayed speed states from a previous iteration;

determining speed control errors based upon a difference between estimated speed states for the multi-mode transmission and reference speed states for the multi-mode transmission;

selecting transmission range equations associated with the presently applied clutches wherein each of the selected transmission range equations corresponds to a respective operating range state of the multi-mode transmission;

executing the closed-loop speed control system including employing the selected transmission range equations to estimate speed states for the multi-mode transmission based on the adjusted open-loop torque commands and delayed speed states from the previous iteration;

determining torque errors based upon said estimated speed states for the multi-mode transmission; and

employing the torque errors to control operation of the multi-mode transmission.

8. The method of claim 7 , wherein employing the torque errors to control operation of the multi-mode transmission comprises employing the torque errors to adjust open-loop motor torque commands for controlling torque machines configured to transfer torque to the multi-mode transmission.