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johnwu 12-09-2017 12:03 AM

Kneeling model
Hi AnyBody,

I just start build a kneeling model by modifying existing SeatedHuman. In the experiments, we have the kinematics of whole body and the interface pressure between the knee and floor. I wish predict the knee contact pressure and to compare it with the test data.

I think the interaction between the floor and knee is not correctly built and need your help. Also, I need your help to add contact force on the soft tissues in thigh.


pgalibarov 12-13-2017 03:29 PM

Hi John,

The easiest way to add those contact elements is to have a look at how it is implemented in the SeatedHuman model.

The conditional contact is defined between the backrest and the spine - you may want to copy and adjust this code for the shank segments. You are probably aware of the logic there - the expected contact nodes are defined on the shank segments, and pushing muscles are added between these nodes and objects representing the floor.

Please have a look at, say:
ammr\Application\Examples\SeatedHuman\Model\SeatSu pport.any

Similarly, you could add conditional contact between two segments by defining expected contact nodes on, for example, thigh and introducing pushing muscles to the shank.

In my opinion this is the easiest that could be done.

Please let me know if that is clear and you have any further questions.

Kind regards,

johnwu 01-24-2018 01:12 AM

I am still working on my kneeling model.

1. I have modified the existing Standing model to fit my purpose.
2. I am driving the model via joints using my test data.
3. I have here one problem: it seems I can drive the shoulder and elbow joints, but not the knee and ankle joints.

johnwu 01-24-2018 11:37 PM

I think I figure out the problem: I have put drivers on wrong places.

johnwu 02-02-2018 01:54 AM

Hi AnyBody,

I need your help to find out problem in my model. I am still working on my kneeling model. The model works in kinematics, but it fails in inverse dynamics. It makes muscle recruitment error, even I switch off all muscles.


johnwu 02-05-2018 09:37 PM


I am still struggling with the model. Now, I have simplified the model to include only one leg. The model works. But, it does not work with both legs on.


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