PHYSICALLY BASED MODELING OF DEFORMABLE SOIL FOR MACHINE DESIGN AND OPERATOR TRAINING

摘要

In recent years, realistic simulation of vehicles on soft soil has been increasingly gaining importance due to its use in operator training, mission planning and design. Soil exhibits a multitude of different behaviors depending on material properties and deformation history, which makes simulation of soil a challenging task, especially at interactive rates. In this work, a real-time soft soil simulation method is presented which strikes a balance between sufficient fidelity for design in engineering, and sufficient performance for Virtual Reality training applications. The method employs models from terramechanics and soil mechanics in order to represent the interaction of vehicles and their digging tools with a deformable terrain, supporting the simulation of a broad range of vehicles with earth moving equipment on soft ground in real-time. The impact of both wheel-ground and tool-ground interactions on the vehicle behavior is considered through use of a fully coupled dynamics model of the vehicle and its environment, which includes effects such as non-linear stress-strain relationships as well as highly plastic material deformation and flow, soil erosion and compaction. Simulation studies are presented which show that the method produces believable terrain deformations and plausible soil reaction forces at real-time frame rates. Furthermore, in verification experiments it is shown that the employed wheel-ground interaction model yields vehicle trajectories in simulation which closely match trajectories observed in experiments with the actual vehicle.