Development of Adaptive Structure by Variable Geometry Truss (Application of Movable Monument in Expo 2005)

This paper describes the large-scale movable monument exhibited at the International Expo 2005, Aichi, Japan, as the first application of an adaptive structure using a VGT mechanism. This monument is composed of three identical movable towers comprising four truss members combined by VGT at joints. The VGT is an adaptive truss with an extensible actuator, so the monument's shape can be changed variably by controlling the length of each of its extensible actuators. In the application of the VGT to the movable monument, security against accidents was examined and authorization for the structure's design was acquired. Further, the control system's safety mechanism, management and operation manual were studied and approved. During the 185 days of the Expo, the monument was operated continuously for about 13 hours a day, and there was not a single breakdown or accident. Continuous safe and excellent performance was achieved, and the monument received high appraisal from promoters and many attendees.