GENETIC MODELLING AND VIBRATION CONTROL OF A TWIN ROTOR SYSTEM

A dynamic model for the characterisation of a twin rotor multi-input multi-output system (TRMS) in hovering mode is extracted using genetic algorithms (GAs). The TRMS behaviour in certain aspects resembles that of a helicopter, with a significant cross-coupling between longitudinal and lateral directional motions. Hence, it is an interesting identification and control problem. The global search technique of GA is used to identify the parameters of the TRMS based on one-step-ahead prediction. The extracted model is then employed for designing and implementing a feedforward/open-loop control law for vibration suppression. Open loop control is often the preliminary step for development of more complex feedback control laws. The paper investigates open-loop control strategies using shaped command inputs for resonance suppression in the TRMS. Digital low-pass filtered/shaped input is used on the TRMS test bed, based on the identified modes of vibration. The approach has shown to result in satisfactory vibration reduction.

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