Adaptive Truss Structures.

Kurzfassung

Within the frameworks of the DLR-project ARES (Actively Reacting Flexible Structures) advanced space structures with integrated sensors and actuators are currently being investigated for the vast advantages they offer in adaptive control over conventional and external actuator/ sensor technology. When designing these adaptive structures, the locations of the actuators must be chosen properly, because they influence the efficiency of the control forces and the stability of the whole system. In order to find the optimal placements of piezo-electric actuators in adaptive truss structures, optimal placement strategies developed in conjunction with the independent modal space control method are used in this paper. For this purpose, a finite truss element is developed accounting for the piezo-electric actuators. By using this finite element, eigenvectors consisting not only of nodal displacements but also of electric potentials are computed. The optimization algorithm calculating the optimal actuator placements makes use of the electric potentials to minimize the control effort. The minimization of the spillover energy into uncontrolled modes is an additional objective which can be taken into account by the optimization procedure. The method is illustrated by numerical examples.