CHS: Small: Fast simulation of geometrically complex multibody systems in contact and self-contact

CHS：小型：快速模拟接触和自接触的几何复杂多体系统

• 批准号: 1422869
• 负责人: Jernej Barbic
• 金额: $ 48.42万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1422869&HistoricalAwards=false
• 关键词: CHS; Small; Fast; simulation; geometrically

The ability to simulate complex machinery in contact is broadly applicable to engineering practice. It can be used for virtual training, say in the operation of heavy machinery. Perhaps most importantly, it can be used to assemble and test complex mechanical structures in virtual reality (using a human-computer interface that includes haptic feedback). Such virtual prototyping, as it is commonly called, greatly shortens design cycles, decreases errors, improves product safety and saves millions of dollars in R&D costs. Applications can be found anywhere a complex structure must be designed and manufactured out of many component parts: airplanes, cars, trains, spaceships, power plants, buildings, tools, heavy equipment, etc. In this project the PI will develop computationally efficient collision detection and contact resolution methods that can accommodate complex systems consisting of many objects that are connected by joints and undergoing contact and self-contact. His goal is to devise algorithms that are sufficiently fast to accommodate high update rates (1,000 simulation steps per second for haptics, or more), and that scale to complex real-world mechanisms typically represented by millions of triangles, such as an internal combustion engine or an entire car engine compartment, an airplane landing gear or airplane doors, or excavator machines. Furthermore, whereas previous fast successful industrial penalty-based methods have typically been limited to pairs of objects in contact, in this research the PI's objective is to deal with more complex and realistic situations including rigid objects, joints, friction and self-contact.Fast simulation of multi-body systems in contact is challenging due to the severe computational and stability requirements imposed by complex geometry. Such simulations frequently involve distributed contact, that is to say contact involving many collision sites of varying surface areas and normal orientations that change rapidly over time. Because it is challenging for constraint-based methods to resolve such contact stably at high update rates, the Principal Investigator will exploit industry-proven penalty methods between points and implicit functions (distance fields or voxmaps), and he will extend the approach, which has to date been limited to pairs of objects in contact, to accommodate N = 2 objects in arbitrary contact, as well as objects connected with joints and undergoing active control. The technical challenges include how to stably resolve and time-step distributed contact between N = 2 objects, how to stably simulate and render 6-DOF distributed contact in the presence of constraints (joints), and how to handle self-contact and incorporate friction, all the while maintaining high update rates (or gracefully degrading them in case of extreme contact). Because the Principal Investigator's preliminary experience suggests that the discrete nature of current algorithms is an important limitation in practice, he will also investigate continuous collision detection between points and distance fields. Project outcomes will be transitioned to engineering practice via the PI's ongoing collaborations with a number of industrical leaders in high-tech virtual prototyping, and will advance the state of the art in computer graphics, haptics, robotics and virtual reality.

模拟复杂机械接触的能力广泛适用于工程实践。 它可以用于虚拟培训，比如重型机械的操作。 也许最重要的是，它可以用于在虚拟现实中组装和测试复杂的机械结构（使用包括触觉反馈的人机界面）。 这种通常被称为虚拟原型的技术大大缩短了设计周期，减少了错误，提高了产品安全性，并节省了数百万美元的研发成本。 应用可以在任何必须由许多组件设计和制造的复杂结构中找到：飞机、汽车、火车、宇宙飞船、发电厂、建筑物、工具、重型设备等。在这个项目中，PI将开发计算效率高的碰撞检测和接触解决方法，这些方法可以适应由许多通过关节连接并经历接触和自接触的物体组成的复杂系统。 他的目标是设计出足够快的算法，以适应高更新速率（触觉每秒1,000步或更高），并扩展到通常由数百万个三角形表示的复杂的现实世界机制，例如内燃机或整个汽车发动机舱，飞机起落架或飞机门，或挖掘机。 此外，而以前的快速成功的工业惩罚为基础的方法通常被限制到对接触的对象，在这项研究中PI的目标是处理更复杂和现实的情况下，包括刚性物体，关节，摩擦和self-contact.Fast模拟接触的多体系统是具有挑战性的，由于严格的计算和稳定性的要求所施加的复杂的几何形状。这种模拟经常涉及分布式接触，也就是说，接触涉及许多不同表面积和法向方向的碰撞点，这些碰撞点随时间迅速变化。 由于基于约束的方法在高更新速率下稳定地解决此类接触具有挑战性，因此主要研究者将在点和隐式函数之间利用行业证明的惩罚方法（距离场或体素图），并且他将扩展该方法，该方法迄今为止仅限于接触的对象对，以适应任意接触的N = 2个对象，以及与关节连接并接受主动控制的对象。 技术挑战包括如何稳定地解决N = 2个对象之间的分布式接触和时间步长，如何在存在约束（关节）的情况下稳定地模拟和呈现6-DOF分布式接触，以及如何处理自接触和合并摩擦，同时保持高更新速率（或在极端接触的情况下适度地降低它们）。 由于首席研究员的初步经验表明，目前的算法的离散性是一个重要的限制，在实践中，他还将研究点和距离场之间的连续碰撞检测。 项目成果将通过PI与一些高科技虚拟原型行业领导者的持续合作过渡到工程实践，并将推进计算机图形学，触觉，机器人和虚拟现实的最新技术。