How to drive a model by force?

I want to move a segment by a constant force.
the file are here:

but when I build model and run “Kinematics” operation in the list tree, I can’t see the segment moved by force. I constrained the segment and run “Inverse Dynamics” operation and see the reaction force in the chart.

Can ANYBODY make models moved “just” by forces? If it can do so, how can I do in my anyscript?


Please find a new update to the Wiki pages on this topic, this should answer your question.

Best regards

Thank you toerholm,

My AMS version is 5.0
using AMMRV 1.3.1

I practiced the model on the wiki updates and found that it would not work if I change the spring force to a constant value.  Although the model is driven by force, it can be work only on the static system, not dynamic system.  It is a really good example for a model driven "just" by forces.

I am doing a study about how the forces change on human movement while doing some movement such as walking, running, etc.  It is a dynamic study, not static study.  Nevertheless, I can't find any example about the study in the AMMRV folder, so I upload a simple example that I made to realize whether ANYBODY can do such analysis.

Thank you for your answer,


Hi Fiercecat,

As you have found this way of solving the problem requires there to be some stiffness. If you set the stiffness to a constant value the FDK solver will not be able to work.

I am sorry but i did not see any attachment to the post?

Best regards