love@hydraulic 发表于 2013-4-2 10:35:17

AMESim仿真的时候提示error detected in DASSL




AMESim仿真的时候提示error detected in DASSL

请教大家怎么解决这个仿真问题

wangwen5955 发表于 2013-4-5 12:04:03

你好,DASSL是微分代数方程集成算法的意思,在AMESim的HELP之中能找到,入选所示:

DASSL is probably the best differential algebraic equation integration algorithm currently available and is certainly the only one that is widely used. It uses a collection of integrators of the same type as those employed in Gear's method. Differential algebraic equations often behave like ordinary differential equations with a time constant that tends to zero so this is hardly surprising. Non-stiff integrators do not work well with differential algebraic equations.

Implicit systems are usually a set of constraint equations and/or implicit equations. Solving this kind of system requires the use of specific Newton-base iterative methods. These methods need to solve a linear system to evaluate the amount by which an iterative variable will be changed to converge towards the solution at a given time.

To solve this kind of system the user can choose two types of method:

·        The LU algorithm which is based on the well-known Gaussian elimination method, which will solve the given system in a direct way.
·        A Krylov method, which is based on minimizing residuals on Krylov subspaces, and then iterating over subspaces towards the real solution of the initial system.
The default choice for the implicit integrator is the direct method, which is the most commonly-used method for solving this kind of system. An iterative matrix is computed and factored, then used in as many steps as possible.

Nevertheless, it is possible that integration of nontrivial Differential Algebraic Equations (DAE) will require the use of a preconditioner (the iteration matrix becomes more and more badly-conditioned as the step-size reduced). Then a preconditioner matrix (an approximation of the initial iteration matrix) is computed and used in as many steps as possible. This last feature is only available with the iterative method, and is appropriate for large system integration.

These two methods differ only in the way the linear systems arising in integration are solved, as initialization and time stepping algorithms remain the same.

ambulance 发表于 2013-4-5 13:38:20

真心没有遇到过这样的问题。。。

hushengxin 发表于 2013-12-23 16:28:44

遇到了同样的问题,请问楼主怎么解决的?

水宝兵兵 发表于 2016-4-28 20:23:17

遇到了同样的问题,请问楼主解决了吗?求指导

带头大哥 发表于 2016-4-30 20:47:55

这是因为你的模型中有代数环,相当于计算机进入了一个死循环,你可以参考下怎么消除代数环

yiliya 发表于 2016-5-4 11:29:26

这个问题基本上是关于平面机构库的使用,问题在于系统装配问题,所以我建议他重新检查一下机构的装配情况。

276089470 发表于 2016-7-5 10:34:56

有没有PID控制,看看输入输出附近的数值,是否有零或者无限大,无限小之类的

小跟爸爸 发表于 2018-4-14 08:40:49

yiliya 发表于 2016-5-4 11:29
这个问题基本上是关于平面机构库的使用,问题在于系统装配问题,所以我建议他重新检查一下机构的装配情况。

楼主你说的很对,我就是加入了平面机构才出现了这个问题,而且仿真时间非常慢,你可以给我看看嘛?我的QQ:759059246,希望得到你的帮助

小跟爸爸 发表于 2018-4-14 10:34:51

yiliya 发表于 2016-5-4 11:29
这个问题基本上是关于平面机构库的使用,问题在于系统装配问题,所以我建议他重新检查一下机构的装配情况。

可以具体解释一下吗?具体检查机构的哪些装配情况C:\Users\Administrator\Desktop
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