Structural Optimization of Motion Structure using Constraint Force Design Method

1. Abstract This research develops a new structural optimization method for foldable motion structure with repeated rigid-body mechanism cell. Compared with conventional rigid-body mechanism, there are many kinematic advantages of a motion structure as it can achieve large shape transformation for real applications such as satellite solar panels, space antennas to shelters, and swimming pool cover. Until now, many researches related with the design of foldable motion structure are focused on how to design an internal spatial unit structure to dictate the nature of structural deformability. However, only designing an internal spatial unit structure has limitations to design an arbitrary shaped structure. Therefore, this research proposes a new motion structure design approach which determines the rotational direction of joints and setting angles between unit cells by using a genetic algorithm to design an arbitrary shaped structure. The straight rigid bars connected by pivot joints are used as an internal spatial unit and an appropriate formulation of objective function is proposed which gives a desired motion structure after an optimization. Through the proposed motion structure design method, the rotational direction of joints and setting angles of several unit cells can be determined automatically and this leads to obtain a desired arbitrary shaped structure in stable. 2.