Spray pattern analysis using wet-mix concrete for model based process control towards automated construction

摘要

A new concept for modeling the material placement in a wet-mix shotcrete process is presented in this paper. The approach uses a combination of Gaussian-type functions to approximate the mass flux distribution together with splitting up the spray process into a free jet and a wall jet part. The effects of dynamic nozzle motions are taken into account resulting in a virtual point of impact which does not necessarily coincident with the current nozzle position. As part of a process parameter analysis at our experimental facility measurements have been performed which are used for model identification and validation. Furthermore, the presented spray pattern model is included into a process control system for the production of test specimens made from sprayed wet-mix concrete. These components are built up layer by layer in an automated process heavily relying on the quality of the process model. The results show accurate production and highlight the capabilities of the presented method.