• 论文 •    

多体系统动力学仿真向后微分公式算法

马秀腾1,2,翟彦博1,罗书强1   

  1. 1.西南大学 工程技术学院,重庆北碚400715;2.现代汽车零部件技术湖北省重点实验室,湖北武汉430070
  • 收稿日期:2013-01-25 修回日期:2013-01-25 出版日期:2013-01-25 发布日期:2013-01-25

Dynamics simulation of multi-body system based on backward differentiation formulas

MA Xiu-teng1,2,ZHAI Yan-bo1,LUO Shu-qiang1   

  1. 1.College of Engineering and Technology, Southwest University, Chongqing 400715, China;2.Hubei Key Laboratory of Advanced Technology for Automotive Components,Wuhan 430070,China
  • Received:2013-01-25 Revised:2013-01-25 Online:2013-01-25 Published:2013-01-25

摘要: 针对多体系统动力学仿真中需要求解DAEs形式运动方程的问题,提出基于向后微分公式的DAEs算法。将已有的求解指标-3DAEs形式运动方程的NStiff算法推广到求解非完力学整系统指标-2DAEs形式的运动方程;提出了NStiff-v算法,分别求解完整约束多体系统指标-3DAEs和非完整力学系统指标-2DAEs形式的运动方程。离散过程中对约束方程进行缩放,消除了Newton-Raphson方法求解非线性方程组时由于步长较小而存在的Jacobian矩阵病态问题。通过曲柄滑块机构和Snakeboard模型两个实例,比较NStiff算法和NStiff-v算法的结果来验证算法的有效性,并比较了效率。算例说明算法求解DAEs时具有二阶精度。

关键词: 多体系统, 约束方程, 微分-代数方程, 向后微分公式, 算法

Abstract: Aiming at the problem of solving DAEs'motion equation in multi-body system dynamics simulation, new methods were proposed based on Backward Differentiation Formulas (BDF). The existing algorithm of NStiff which solved index-3DAEs form motion equation was extended to the index-2DAEs form motion equation of non-holonomic mechanics system. A new algorithm of NStiff-v was proposed to solve index-3DAEs form motion equation of holonomic constraint multi-body system and index-2DAEs form motion equation of non-holonomic mechanical system. During the discretization of motion equations, the constraint equations were scaled to eliminate ill-conditioning of Jacobian matrix caused by small time steps on solving nonlinear equations with Newton-Raphson method. Through two examples of slider-crank mechanism and Snakeboard model, the effectiveness of proposed algorithm was validated by comparing NStiff with NStiff-v. In addition, experiments illustrated that the algorithm had second-order accuracy in solving DAEs.

Key words: multi-body system, constraint equation, differential-algebraic equations, backward differentiation formulas, algorithms

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