FROM ACTIVE TO INTELLIGENT STRUCTURES 1

This paper reports on the construction of a unique active tensegrity structure containing five modules and ten actuators on telescopic bars in a closely coupled configuration. The control scenario under study is a constant slope requirement for quasi-static control. Controlling for serviceability requirements is more likely to be of practical use than controlling for structural safety events having long return periods since for the latter application, reliability requirements on controllers would make costs prohibitive. Behaviour is geometrically nonlinear and this is modelled using a combination of dynamic relaxation analysis with a neural-network based correction. There is no direct solution for bar movements given required slope. Furthermore, the entire search space is so large that a brute force method of generate, analyse and test would take up to 10 18 years to find a control solution. Stochastic search reduces this time down to approximately one hour. Case based reasoning with stochastic search reduces it further down to tens of seconds. Adding cases allows the structure to learn through experience. We are currently studying self diagnosis and self repair – two other characteristics of intelligent (and not merely smart) structures.