Experimental active control of a two-dimensional truss

A flexible two-dimensional structure was actively controlled by using a single space realizable linear proof mass actuator. The NASA/UVA/UB actuator was attached to the flexible planar truss structure at an optimal location and it was considered as both a passive and an active device. The theoretical model of the system obtained by using the MSC/PAL package was modified so that it included the actuator dynamics. The theoretically predicted passive and active control law was experimentally verified. The electronic stiffness of the actuator was specified, such that the proof mass actuator system was tuned to the fourth structural mode of the truss by using traditional vibration absorber design for multiple degree-of-freedom systems. The active control law was experimentally implemented in the form of velocity feedback by integrating the signals of two accelerometers attached to the structure. The two lower modes of the closed-loop structure were placed further in the left-hand side of the complex plane. The stability of the closed-loop system was also examined. It was also illustrated experimentally that increasing the gains at higher than the optimal values drove the closed-loop system unstable, as it was theoretically predicted.<
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