A multiscale model for real-time simulation of terrain dynamics is explored. To represent the dynamics on different scales the model combines the description of soil as a continuous solid, as distinct particles and as rigid multibodies. The models are dynamically coupled to each other and to the earthmoving equipment. Agitated soil is represented by a hybrid of contacting particles and continuum solid, with the moving equipment and resting soil as geometric boundaries. Each zone of active soil is aggregated into distinct bodies, with the proper mass, momentum and frictional-cohesive properties, which constrain the equipment's multibody dynamics. The particle model parameters are pre-calibrated to the bulk mechanical parameters for a wide range of different soils. The result is a computationally efficient model for earthmoving operations that resolve the motion of the soil, using a fast iterative solver, and provide realistic forces and dynamic for the equipment, using a direct solver for high numerical precision. Numerical simulations of excavation and bulldozing operations are performed to validate the model and measure the computational performance. Reference data is produced using coupled discrete element and multibody dynamics simulations at relatively high resolution. The digging resistance and soil displacements with the real-time multiscale model agree with the reference model up to 10-25%, and run more than three orders of magnitude faster.

中文翻译：

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用于实时土方运动模拟的地形动力学多尺度模型

探索了用于实时模拟地形动力学的多尺度模型。为了在不同尺度上表示动力学，该模型结合了土壤作为连续固体、不同颗粒和刚性多体的描述。这些模型彼此动态耦合，并与运土设备动态耦合。搅拌土由接触颗粒和连续固体的混合体表示，移动设备和静止土壤作为几何边界。活动土壤的每个区域都聚集成不同的物体，具有适当的质量、动量和摩擦-内聚特性，这限制了设备的多体动力学。颗粒模型参数针对各种不同土壤的整体力学参数进行了预校准。结果是一个计算效率高的土方作业模型，使用快速迭代求解器解决土壤运动，并为设备提供真实的力和动态，使用直接求解器获得高数值精度。进行挖掘和推土操作的数值模拟以验证模型并测量计算性能。参考数据是使用耦合离散元件和多体动力学模拟以相对较高的分辨率生成的。实时多尺度模型的挖掘阻力和土壤位移与参考模型的一致性高达 10-25%，并且运行速度提高了三个数量级以上。使用直接求解器以获得高数值精度。进行挖掘和推土操作的数值模拟以验证模型并测量计算性能。参考数据是使用耦合离散元件和多体动力学模拟以相对较高的分辨率生成的。实时多尺度模型的挖掘阻力和土壤位移与参考模型的一致性高达 10-25%，并且运行速度提高了三个数量级以上。使用直接求解器以获得高数值精度。进行挖掘和推土操作的数值模拟以验证模型并测量计算性能。参考数据是使用耦合离散元件和多体动力学模拟以相对较高的分辨率生成的。实时多尺度模型的挖掘阻力和土壤位移与参考模型的一致性高达 10-25%，并且运行速度提高了三个数量级以上。