Two Methods for the Identification of Uncertain Parameters of an Architectural Cable Net Geometry

Abstract

Recently, a control algorithm has been presented to control the geometry of a prestressed flexible cable net formwork, which is used for the construction of anticlastic thin concrete shell structures in architecture. The most important uncertainties in the model of the cable net are the parameters of unstressed lengths of its edges. As the control algorithm is model-based, its performance depends on the knowledge of these parameters. We present two methods for their identification, which are based on measurements of different configurations of the tensioned cable net. The first identification method uses a change of variables and a linear least squares approach. The second one is based on an optimization problem, which is solved in a distributed way by the Alternating Direction Method of Multipliers (ADMM) and is robust against the expected measurement noise. A numerical example demonstrates the performance of the identification methods.