Parameter Identification for Digital Fabrication: A Gaussian Process Learning Approach

Tensioned cable nets can be used as supporting structures for the efficient construction of lightweight building elements, such as thin concrete shell structures. To guarantee important mechanical properties of the latter, the tolerances on deviations of the tensioned cable net geometry from the desired target form are very tight. Therefore, the form needs to be readjusted on the construction site. In order to employ model-based optimization techniques, the precise identification of important uncertain model parameters of the cable net system is required. This paper proposes the use of Gaussian process regression to learn the function that maps the cable net geometry to the uncertain parameters. In contrast to previously proposed methods, this approach requires only a single form measurement for the identification of the cable net model parameters. This is beneficial since measurements of the cable net form on the construction site are very expensive. For the training of the Gaussian processes, simulated data is efficiently computed via convex programming. The effectiveness of the proposed method and the impact of the precise identification of the parameters on the form of the cable net are demonstrated in numerical experiments on a quarter-scale prototype of a roof structure.

[1]  Manfred Morari,et al.  Two methods for the identification of uncertain parameters of an architectural cable net geometry , 2016, 2016 IEEE Conference on Control Applications (CCA).

[2]  Xuyou Yang,et al.  Robotic variable fabric formwork , 2019, J. Comput. Des. Eng..

[3]  Lisa Turner,et al.  Applications of Second Order Cone Programming , 2012 .

[4]  Lennart Ljung,et al.  System Identification: Theory for the User , 1987 .

[6]  Roy S. Smith,et al.  Robust Control of a Lightweight Structure for Digital Fabrication , 2020 .

[7]  Carl E. Rasmussen,et al.  Gaussian processes for machine learning , 2005, Adaptive computation and machine learning.

[8]  Farzaneh Tahmoorian,et al.  A state of the art on the structural performance of fabric formwork systems , 2020 .

[9]  Philippe Block,et al.  NEST HiLo: Investigating lightweight construction and adaptive energy systems , 2017 .

[10]  Andrew Liew,et al.  Active control of a rod-net formwork system prototype , 2018, Automation in Construction.

[11]  Stephen P. Boyd,et al.  Convex Optimization , 2004, Algorithms and Theory of Computation Handbook.

[12]  Manfred Morari,et al.  Control of an Architectural Cable Net Geometry , 2018, IEEE Transactions on Control Systems Technology.

[13]  Manfred Morari,et al.  Sequential quadratic programming for the control of an architectural cable net geometry , 2016, 2016 American Control Conference (ACC).

[14]  Yvonne R. Stürz,et al.  Optimization-Based and Distributed Control for Digital Fabrication , 2019 .