Active control of vibrations in helicopters via pole assignment techniques

This paper is motivated by the problem of active control of vibrations in helicopter A129 of Agusta S.p.A. Taking into account the specific features of the A129 rotor, whose model is characterized by two nonminimum phase zeros, a new method for active control is proposed. Based on simple pole-placement considerations, the method presents a number of advantages. First, it enables harmonic cancellation without perturbing the low frequency dynamics. In other words, the control system does not affect the overall dynamics of the flight as decided by the pilot. Moreover, it supplies a stable controller. Second, the controller design computations are extremely simple. The performances achievable with such a controller are tested by a number of simulations on an A129 rotor model.>