Feasibility of utilizing active control to minimize torsional vibration of drivelines

This research presents an evaluation of active control of torsional vibration as it relates to drivelines of heavy duty vehicles. In particular, an exploration is made into different techniques for sensing torsional vibration and various closed-loop control algorithms that can be implemented in real time. A mass-elastic model of a typical driveline is created and simulations are performed to demonstrate the ability of various actuators and control algorithm to attenuate torsional vibration.; Three different sensing techniques are presented: analog system using a variable reluctance sensor or encoder and a frequency to voltage converter, a digital system using a timer and counter, and a purely software technique that relies on Prony's method to estimate the vibration frequency and amplitude.; Two different control strategies are presented. The first is the Direct Velocity Feedback which is a simple technique to implement and is guaranteed to be globally stable. The second is a more involved strategy based on the Pulse Control Technique. Although the literature presents Displacement Pulse Control to limit displacement, this work extends the method to Velocity Pulse Control to limit velocities to a predefined threshold. Simulations and experiments are performed on a two degree of freedom rotating system. An investigation into actively reducing torsional vibration of drivelines reveals the specifications actuators must meet before they can be usefully employed. The driveline is modeled using realistic mass-elastic data and the natural frequencies and mode shapes are determined. The system is excited by torque profiles where each profile is phased approximately to simulate the characteristics of the engine powering the system. The torque profile is generated by performing the kinematics analysis of a four bar linkage representing the piston, connecting rod and crank throw assembly.; Simulations are performed at engine speeds at which significant frequency content of the applied torque coincide with the first natural frequency of the driveline. This condition results in resonant torsional vibration. An examination is made into all possible devices/actuators currently available that can be employed to attenuate resonant vibration. A performance index is created to be used as a basis on which to compare the performance of the actuators. A MATLABRTM simulation is performed in which a closed loop control algorithm is implemented for each of the candidate actuators and the performance of the actuators judged according to the performance index.