420 - Modelling and vibration control of a twin rotor system: a particle swarm optimisation approach
Alam M., Tokhi M.
Abstract
The construction and operation of twin rotor multi-input multi-output system (TRMS) in many aspects resemble that of a helicopter, with a significant cross-coupling between longitudinal and lateral directional motions. Moreover, flexible motion due to the unsymmetrical mass distribution of the system causes structural vibration while at operation. Command shaping is an effective control strategy to reduce vibration of flexible dynamic systems. The command shaping method involves convolving a desired command with a sequence of impulses whose amplitudes and time locations are related to system parameters such as damping ratio, natural frequency, resonance mode/modes etc. So, designing a conventional command shaper requires a priori knowledge of the system characteristics. This paper investigates a new method to extract parametric model of the system and to design a command shaper for vibration reduction of the system using particle swarm optimization (PSO) algorithm. PSO is a new optimization method that is based on a social behaviour of groups as fish schooling or bird flocking. Each parameter set, that forms the model or controller, is represented as a particle in the particle swarm. Particles in a swarm move in discrete steps based on their current velocity, memory of where they found their personal best fitness value, and a desire to move towards location(s) where the best fitness value has been found so far by all the particles during a previous iteration. The effectiveness of the proposed algorithms is verified and their performances in vibration suppression are assessed in comparison to the standard input shaper and to the system response with unshaped bang-bang input.
Citation
Alam M.; Tokhi M.: Modelling and vibration control of a twin rotor system: a particle swarm optimisation approach, CD-ROM Proceedings of the Thirtheenth International Congress on Sound and Vibration (ICSV13), July 2-6, 2006, Vienna, Austria, Eds.: Eberhardsteiner, J.; Mang, H.A.; Waubke, H., Publisher: Vienna University of Technology, Austria, ISBN: 3-9501554-5-7
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