Combined design of structures and controllers for optimal maneuverability

Abstract

This paper treats the problem of the combined design of structure/control systems for achieving optimal maneuverability. A maneuverability index which directly reflects the time required to perform a given maneuver or set of maneuvers is introduced. By designing the flexible appendages of a spacecraft, its maneuverability is optimized under the constraints of structural properties, and of the postmaneuver spill-over being within a specified bound. The spillover reduction is achieved by making use of an appropriate control design model. The distributed parameter design problem is approached using assumed shape functions and finite element analysis with dynamic reduction. Characteristics of the problem and problem solving procedures have been investigated. Adaptive approximate design methods have been developed to overcome computational difficulties. It is shown that the global optimal design may be obtained by tuning the natural frequencies of the spacecraft to satisfy specific constraints. We quantify the difference between a lower bound to the objective function associated with the original problem and the estimate obtained from the modified problem as the index for the adaptive refinement procedure. Numerical examples show that the results of the optimal design can provide substantial improvement.