This paper presents the design of a hybrid powertrain damping control algorithm using the sliding mode control (SMC) scheme.
Motor control-based active damping control strategy is used to ensure smooth drive line operation and provide the driver with seamless driving experience. In the case of active damping control, motor and engine speeds are measured to monitor the driveline state, and corrective motor torques are generated to dampen out drive line vibrations. Drive lines are prone to internal vibration (engine, clutches and motors) as well as external disturbances caused by road inputs. As such, fast-response actuator-based damping control systems are desirable in a hybrid powertrain application, where a torque converter is generally not used. The most significant aspect of an active damping control algorithm is the error calculation, based on proper states information, and torque determination based on the adaptive control gain applied to the nonlinear system. For the proposed control approach, reference states are computed for different transmission modes and the tracking errors are calculated using actual measured states. The damping control torque is determined using the proposed SMC, which is developed after an analysis of the drive line model, and uses the motors as actuators to minimize the effects of internal and external disturbances. This control algorithm is developed for a power-split hybrid powertrain system and the response of the powertrain under the damping control is evaluated using vehicle-level testing, and results are discussed.