Study On Robust Vibration Control For Helicopter Structure

The vibration level of helicopter fuselage is an important indicator for assessing the performance of a helicopter. Therefore helicopter vibration is paid considerable attention. Because of its excellent adaptability, flexibility and the efficiency in vibration reduction, active control has become a new technology used to seeking more efficient methods for vibration reduction. When helicopter is in flight, the altitude, speed and flight attitude change with time, which make certain fluctuations of vibration frequency and amplitude. In addition, changes of the structure parameters of helicopter in operation also alter the transfer characteristics of control channels. Therefore it is needed to study an effective, robust, simple engineering control algorithm.Firstly the realization in engineering practice of the mixed sensitivity design method and mu-synthesis approach, and principles and methods for choosing different weight functions are studied. Correspondingly robust controllers are designed based on the helicopter model. Simulations show the better robustness in different situations. On this base, different design methods are compared and analyzed. Secondly, in order to improve the control performance and system redundancy, an adaptive feedforward controller based on FXLMS algorithm is introduced to form the hybrid control. These methods adopt off-line modeling and overcome the problem of online identification and computation. In the design process full account of the perturbation and parameter changes are considered, which makes the designed controller have certain robustness. Effective choice of weight function reduces the input energy. At last, the corresponding DSP software is compiled. Experimental results for free-free beam vibration reduction show that robust controller can provide good robustness.