United States Patent Application Publication Number 2007/0225887 to Morris provides a multivariate control method and system to control torque output from a powertrain system to a driveline. The powertrain comprises a hybrid powertrain having a plurality of torque-generative devices connected to a transmission. Desired powertrain and driveline operating states are determined, as are a plurality of operating state errors. Each torque-generative device is controlled, based on the operating state errors, and operating mode of the transmission. A damping torque command, additive to a commanded torque, is determined for one or more of the torque-generative devices based on the determined transmission operating mode.
U.S. Pat. No. 7,344,129 to Nemoto provides a damping method for a hybrid vehicle in which a power unit consisting of an engine and a motor is supported in a vehicle body frame via an active vibration isolation support system. The method includes a step of damping vibration of the power unit by the active vibration isolation support system, and a subsequent step of controlling operation of the motor to damp vibration that has not been eliminated by the active vibration isolation support system.
U.S. Pat. No. 6,629,025 to Evans et al. provides a surge suppression control for a motor vehicle drivetrain that detects and suppresses drivetrain oscillation in a predetermined range of frequencies centered on an estimate of the natural frequency of the drivetrain. The drivetrain natural frequency is determined based on the current speed ratio of the vehicle transmission and empirically determined vehicle characteristics, and is used to define the center frequency of a band-pass filter responsive to engine speed. The filter output represents the AC component of the engine speed in a range of frequencies centered on the driveline natural frequency, and such component is differentiated to form an acceleration component in phase synchronism with the torque causing the detected resonance. An electric machine mechanically coupled to the engine is energized in accordance with the inverse of the acceleration component to actively cancel the detected resonance whenever the acceleration component exceeds a noise threshold that also is adjusted based on the estimated natural frequency of the drivetrain.