Modal analysis and active vibration control of the Naval Postgraduate School Space Truss
Johnson, Scott E.
Agrawal, Brij N.
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This thesis examines active control of the Naval Postgraduate School (NPS) Space Truss using a piezoceramic stack actuator. Preceding the development of an active control mechanism for the NPS space truss, modal testing was performed to identify the modal properties of the truss. An impact hammer provided excitation to the truss and accelerometers easured the truss' response. Two data acquisition systems were used independently to gather and analyze data. For active control, an active strut, consisting of a piezoceramic stack, a force transducer, and mechanical interfaces, was substituted in place of a critical diagonal strut and acted as a control actuator. The frequency response of the system was determined and a integral plus double-integral force feedback control law was designed and implemented. A linear proof mass actuator was employed to excite one of the truss' vibrational modes. The controller then suppressed the vibration along the length of the structure resulting in power attenuation on the order of 10- 15 dB. Various combinations of velocity and position feedback gains were investigated in order to optimize the control action. Additional testing was performed to determine the controller's sensitivity over a frequency band.
RightsThis publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
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