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 test 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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用于实时土方模拟的多尺度地形动力学模型

探索了一种用于地形动力学实时仿真的多尺度模型。为了代表不同尺度的动力学，该模型结合了对土壤的描述，将其描述为连续的固体，不同的颗粒和刚性的多体。这些模型彼此动态耦合，并与土方设备动态耦合。搅动的土壤以接触颗粒和连续固体的混合体为代表，移动的设备和静止的土壤为几何边界。活性土壤的每个区域都聚集到不同的物体中，这些物体具有适当的质量，动量和摩擦粘结特性，从而限制了设备的多体动力学。粒子模型参数已针对多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很高的土方工程模型，该模型使用快速迭代求解器解析土壤的运动，并使用直接求解器以提供较高的数值精度，为设备提供逼真的力和动力。进行开挖和推土作业的数值模拟以测试模型并测量计算性能。参考数据是使用耦合的离散元素和多体动力学仿真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一致，最高可达10–25％，运行速度快三个数量级以上。使用直接求解器可获得较高的数值精度。进行开挖和推土作业的数值模拟以测试模型并测量计算性能。参考数据是使用耦合的离散元素和多体动力学仿真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一致，最高可达10–25％，运行速度快三个数量级以上。使用直接求解器可获得较高的数值精度。进行开挖和推土作业的数值模拟以测试模型并测量计算性能。参考数据是使用耦合的离散元素和多体动力学仿真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一致，最高可达10–25％，运行速度快三个数量级以上。