| Airborne precision instruments undertake the tasks of navigation, control, detection and communication, which are very necessary to ensure aircraft work in good condition. But the inevitable vibration disturbances are affecting the normal running of these instruments. So it is essential to take measures to isolate the vibration.Pure passive vibration isolation method and pure active isolation method both have their own shortcomings. In order to improve the vibration environment of airborne precision instruments efficaciously, it is necessary to combine passive and active methods to develop a hybrid vibration isolation technology.A rubber element is selected as the passive component of the hybrid isolator considering its excellent stiffness and damping characteristics. A laminated PVDF actuator is made after the properties of PVDF piezoelectric film is detailed studied. The new designed actuator is thin, light and flexible, and is used as the active component of the hybrid isolator.A new type of hybrid isolator is designed and manufactured, which is constituted with the rubber element and laminated PVDF actuator in series form. The hybrid isolator’s passive characteristics are researched and the influence of the elements of the hybrid isolator on its passive performance is studied by a simulation approach.The features of different feedback methods are investigated and the different performances between proportional feedback control method and Bang-Bang control method are discussed. Then an improved Bang-Bang control method is proposed. Afterwards, the effectiveness of the hybrid isolator is verified by experiments. Experimental results indicate that the hybrid isolator can achieve better performance than pure passive isolator, especially in the resonance region; the results also show that the improved Bang-Bang control method is more efficient than the proportional feedback control method.A kind of three direction hybrid isolator is preliminary designed at the end of the thesis as a basis for further study in future. |
