机器人adams

ERROR: The Initial Conditions displacement solution failed to converge.
Adams/Solver could not determine the assembled position configuration of the model.
Possible Causes and Suggested Course of Action:
Check for redundant constraints, and if any present try to eliminate as many as possible.
Check to see that the motion functions are consistent with other
aspects of the current model position.
Check to see if joints are inconsistent (contradictory); eliminate them if so.
Check to see if parts are not too distant from an assembled configuration.
ERROR: Simulation failure detected.
ERROR: Simulation failure detected.
ERROR: Simulation failure detected.
ERROR: Simulation failure detected.
拜求大神帮忙。当把机架与地面固定住的时候腿是可移动的。但是，当把机架放开后，添加与地面之间接触力就出现了上述这些问题。但经过我的检查，不存在冗余约束，并且驱动也是没问题的。不知怎么回事。