Abstract
For the forced excitation of a large structure such an airplane using one actuator, all of the natural vibration modes cannot be excited because the vibration does not propagate in the entire structure. Therefore, vibration test of a large structure uses a lot of actuators. When we drive a lot of actuators by multi-point excitation using centralized control, we have to adjust command signals, such as excitation frequencies, magnitude and phase of the excitation force, to every natural vibration mode. However, it takes a long time to measure natural vibrations in this way. Thus, we use a method for driving at resonance point by using the self-excited vibration generated by the local feedback control that an excitation point corresponds to a vibration detection point. However, the self-excited vibration cannot excite all of the natural vibration modes because some natural vibration modes have changed to the other one which is easily excited. Then, we use forced entrainment to excite all of the natural vibration modes by giving continuous exciting force to the actuator situated on the tip of the object in order to synchronize the self-excited vibration actuators. We carried out an experiment about excited point and excited force performing more appropriate, and as a result, we found an appropriate those. Therefore, we carried out an experiment about excited point and excited force performing more appropriate, and as a result, we found an appropriate those. By doing forced entrainment properly, all of the natural vibrations could be measured.
