Simulation model of prestacking at the seaport container terminal

Automation and digitalization of both the entire process and components of technological operations of the terminal are one of the conditions for the balanced development of the port infrastructure of the Russian Federation. Container transshipment in the warehouse area is the most labor-intensive and frequently performed auxiliary operation of the technological process of any container terminal. That is why development of advanced driver assistance systems for mobile reloading equipment based on a digital twin of this operation is in high demand from the point of view of the terminal digitalization. The object of the study is the technological process of containers transshipment in the operating areas of the terminal with formation of auxiliary stacks to speed up the transfer of goods by the different transport means, as well as carrying out other auxiliary operations. The reloader performs the operation of partially dismantling the operational stack with removal from it of a certain number of target containers that make up the logistics flow of cargo moved to the auxiliary stack with the subsequent return of the blocking containers back to their previous stacks of the operational stack. The research method is the modeling of scenarios depending on the sequence of possible states of the simulated technological process. The used mathematical apparatus is automatic programming. The modeling tools are deterministic finite state machine. The main goal of developing the model is to convert the loader control function when performing a selective search operation for containers in an operational stack into a digital code, i. e. mapping the sequence of its possible states into a sequence of characters in the control line of the machine. The result of the study is a digital simulation model of the operation of selective removal of containers from the operational stack with implementation of the work scheme based on the principle of complete disassembly of blocking stacks and removal of containers only from the nearest row, as well as proof of the adequacy of the transition diagram of the finite state machine to the functioning mechanism of the simulated operation. The virtual environment of the automated control system for a mobile loader operating in the rear zone is the place where the digital model of selective removal of containers is used in the architecture of the digital twin of the container terminal. The main advantage of using this version of the finite state machine as an element of the automated control system is that there is no need to urgently interrupt the technological process to adjust operation of the loader at work positions.