Game-Engine-Based 3D Simulation of Mobile Robot and its Application to Autonomous Navigation in Physical Environments

An online-usable digital twin system integrated into a control system is proposed and developed in this study to control an autonomous mobile robot operating on a complex three-dimensional (3D) terrain that includes slopes and uneven surfaces. The system is equipped with validated functions that are necessary for virtual or physical autonomous navigation. In this development, (1) 3D virtual environment, 3D virtual robot model, and 3D virtual sensor models are constructed to accurately reproduce the motion of a mobile robot on a computer. Additionally, (2) by connecting these virtual and physical models through an interface, we integrate them as a digital twin and implement an autonomous navigation control system that is synchronized with a motion simulation by switching between a physical and virtual robot (through a physics engine). This allows the same control system to be applied to both the virtual and physical models. The virtual model is created using the Unity 3D game engine, which integrates environmental terrain data and robot models to enable 3D physical simulations including road slopes and unevenness. Additionally, a path-setting method using Bézier curves and a path-following algorithm are implemented in the simulation system. Autonomous navigation of the mobile robot through the digital twin system is achieved by combining the functions above in a manner that allows online use during operation. Finally, autonomous navigation tests are conducted in a physical environment to confirm the effectiveness of the developed system.