arXiv:2604.19892cs.GRcs.AI2026-04被引 1

提出高效接触模拟新方法,显著提升刚性接触场景下的计算速度。

An Efficient Multilevel Preconditioned Nonlinear Conjugate Gradient Method for Incremental Potential Contact

论文配图:An Efficient Multilevel Preconditioned Nonlinear Conjugate Gradient Method for Incremental Potential Contact
图 1 · 摘自论文原文
  • 用稀疏输入伍德伯里更新动态调整分层预条件器,避免频繁重建
  • 在刚性接触场景下比现有最优方法快5.66倍,收敛更快
  • 适合需要高保真接触模拟的实时物理引擎开发者

增量势能接触(IPC)能保证无穿透模拟,但因牛顿法需昂贵的海森矩阵组装和线性求解而计算成本高昂。尽管预条件非线性共轭梯度(PNCG)可避免海森矩阵组装,但在刚性、高接触密度场景中收敛缓慢,因缺乏有效预条件器:简单雅可比预条件器无法捕捉全局耦合,而高级层次化预条件器如多层加性施瓦茨(MAS)在每次非线性迭代中重建代价过高。本文提出MAS-PNCG,首次实现层次化预条件在非线性优化中的高效应用。关键技术是稀疏输入伍德伯里更新算法,可增量式适应不断变化的接触集,使预条件器维护成本趋近于零,同时保留接触系统的复杂谱特性。此外,将启发式搜索方向替换为考虑海森信息的二维子空间最小化,最优组合预条件梯度与历史方向;还引入快速每子域保守碰撞检测(CCD)方法,确保无穿透轨迹且避免过严的全局步长。实验表明,相比基于MAS预条件的最新牛顿-PCG求解器(GIPC和StiffGIPC),MAS-PNCG分别提速5.66×和2.07×。

原文摘要 · Abstract (English)

Incremental Potential Contact (IPC) guarantees intersection-free simulation but suffers from high computational costs due to the expensive Hessian assembly and linear solves required by Newton's method. While Preconditioned Nonlinear Conjugate Gradient (PNCG) avoids Hessian assembly, it has historically struggled with poor convergence in stiff, contact-rich scenarios due to the lack of effective preconditioners; simple Jacobi preconditioners fail to capture the global coupling, while advanced hierarchy-based preconditioners like Multilevel Additive Schwarz (MAS) are computationally prohibitive to rebuild at every nonlinear iteration. We present MAS-PNCG, a method that unlocks the power of hierarchical preconditioning for nonlinear optimization. Our key technical innovation is a Sparse-Input Woodbury update algorithm that incrementally adapts the fine-level MAS components to rapidly evolving contact sets. This bypasses the need for full preconditioner rebuilds, reducing maintenance cost to near-zero while capturing the complex spectral properties of the contact system. Furthermore, we replace heuristic PNCG search directions with a Hessian-aware 2D subspace minimization that optimally combines the preconditioned gradient and previous direction. We also apply a fast per-subdomain conservative CCD method that ensures penetration-free trajectories while avoiding overly restrictive global step sizes. Experiments demonstrate that our MAS-PNCG outperforms state-of-the-art Newton-PCG solvers, GIPC and StiffGIPC, both preconditioned with MAS up to 5.66$\times$ and 2.07$\times$ respectively.

接触模拟非线性优化预条件物理仿真

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