Powertrain Control for Active Damping of Driveline Oscillations

When a vehicle is subjected to acceleration or disturbances, the elasticity of the various components in the driveline may cause torsional vibrations which can result in an oscillating vehicle speed. These driveline oscillations are also known as shuffle and are low frequency oscillations corresponding to the first resonance frequency of the driveline. The oscillations give rise to, apart from material stress, noticeable lessened driveability. In this work, different ways to actively damp the oscillations are investigated. The idea is to use the engine as an actuator in order to achieve active damping, so-called active engine control. Different linear controllers are investigated and evaluated. The paper includes driveline modelling, control design and verifications by simulations, and tests in real vehicle. Implementation issues such as limited amount of available engine torque and parameter identifications are also discussed. A Linear-Quadratic-Gaussion (LQG) controller has been implemented and tested on a heavy duty truck. Results show that the LQG controller works well and active damping is achieved.