adams刚柔耦合仿真进行到一半，出错而终止，提示如下，为什么呢

ERROR:   At time  2.443409871E-01 the integrator is unable to start/restart.  Possible Causes:

(1) The accuracy required for the numerical solution can not be attained.

Relax (increase) the value of the acceptable integration ERROR.

(2) Incompatible redundant constraints, a lock up, or a bifurcation

situation.  The latter two indicate a mechanism design problem.

(3) The system includes a zero (or relatively small) mass on a part with

an unconstrained translational degree of freedom.

Make sure you have mass on all parts with translational degrees of freedom.

(4) The system includes a zero (or relatively small) inertia on a part

with an unconstrained rotational degree of freedom.

Make sure you have inertias on all parts with rotational degrees of freedom.

(5) An Adams element has a function expression that equals exactly itself.

For example,

SFORCE/id1,I=id2,J=id3,ROT,FUNC=SFORCE(id1,jflag,comp,rm),and

DIFF/id4,IMPLICIT,IC=0,FUNC=DIF1(id4).

Similarly,

VARIABLE/id5, FUNC=VARVAL(id5)*TIME

equals itself at 1 second. Avoid setting an Adams element equal to itself.

ERROR:   Simulation failure detected.

ERROR:   Simulation failure detected.

是不是因为模型存在过约束？但是我检查了，没有过约束呀，还是我没发现？怎么检查模型的约束关系呢？请老师不吝赐教