Path Generation and Execution for Automatic Shotcrete in Railway Tunnels

The shotcrete process has been extensively used for many years in different civil and mining operations. Nevertheless, it is still either applied by an operator which controls the shotcrete nozzle manually or through a remote control. In either case, the operation is entirely controlled by the operator.Automating the shotcrete process involves developments in different parts of the process, such as the tunnel scanning for 3D model generation and the shotcrete path automatic generation and execution.This paper describes the work developed for this last part, namely the automatic generation and execution of a shotcrete path, given the mesh of a tunnel and a set of input parameters, for application in railway tunnels. The developed path also considers specificities of the concrete projection process, such as the uncontrolled flow variation due to the pumping systems, generating a trajectory that aims at minimizing this effect. Results are shown using a realistic simulator and an uneven railway tunnel, using an industrial robot mounted on a railway wagon.