SPILLOVER AND ENERGY CONSIDERATIONS IN THE OUTPUT FEEDBACK CONTROL OF ADAPTIVE STRUCTURES

摘要

In this paper, energy consumption in vibration control of statically indeterminate adaptive structures is investigated. Although, adaptive structures theory is applicable to any type of structure, examples in this paper are based on adaptive truss structures for illustrative purposes. The system is assumed to be autonomous. Vibration control is achieved through the actuators working against element forces. In statically determinate structures, the element forces are generated only by the inertial and dissipative loads, whereas in statically indeterminate structures element stresses are generated not only by inertial and dissipative loads but also by the control elongations. In other words, in statically indeterminate structures, some of the energy supplied by the control is used towards aggravating the controls. In order to overcome this adverse behavior, slave actuators can be used. It is shown that when a sufficient number of slave actuators are employed, element forces due to control elongations are canceled, enabling a statically indeterminate structure to behave as a statically determinate one. It is also demonstrated that the amount of energy required for vibration control is less when slave actuators are used.