Adaptive schemes for the active control of helicopter structural response

This paper describes a new method for the design of an adaptive controller for the reduction of vibration in helicopter structures. Two known approaches are described which can be used to implement an active vibration control system-a frequency domain controller or a time domain controller. Both strategies have a number of advantages and disadvantages, which are discussed in the paper. A new approach to the design of an adaptive controller for the reduction of helicopter vibration is described. This new technique is a hybrid time/frequency domain solution combining the advantages from both the time domain linear quadratic feedback controller and the frequency domain quasi-static controller. Both fixed gain and adaptive control designs have been implemented, and comparisons of the performance of the various control approaches to the problem of minimizing vibration in helicopter structures is made. The hybrid strategy has been studied extensively using computer simulations and its performance has been shown to equal that of the frequency domain approach, providing up to 90 percent vibration reduction at the blade-passing frequency. Results from experimental validation on a helicopter airframe test rig confirm the effectiveness of the strategy