starting with a specific model for kinematical analysis

Hi Frederik

This error message means that you need to supply more constraints to your model. Including 9 markers could be enough it would give you 9x3 dof, but it also depends where these are located, if for example you have none on the hand it would not work since the wrist dof would be undetermined.

Usually it is a good idea to make a small sketch on the dof in the model and the applied drivers and constraints.

Assuming you also have the trunk in the model, is it driven by the markers?

Best regards
Søren

Soren,

thank you for the swift response!
I don’t have any markers on the hand, since I don’t need the hand. Is it possible to exclude the hand out of the arm?
The trunk is indeed included, but I only have 2 markers on the scapula.

Best regards,

Frederik

Hi Frederik

Excluding the hand is not straight forward since it will also involve removal of muscles.

If you have no markers on the hand simply drive the writs joint to a constant position. A good file to find examples on such joint drivers is FreePostureMove/JointrAndDriver.any

Concerning the scapula :
If your two markers is attached to the thorax segment(or scapula?) and you have no other drivers for the trunk segments this will not be enough…

The trunk (pelvis lumbar vertebras and throax ) has in total 9 dof these you can not driver with only two markers. Then you will need to supply more drivers.

Best regards
Søren

Soren,

the driver you reffered to from the other model, is it like this:

//Wrist driver
AnyKinEqInterPolDriver WristDriverRight ={
AnyKinMeasureOrg &ref1 =…HumanModel.Interface.Right.WristFlexion;
AnyKinMeasureOrg &ref2 =…HumanModel.Interface.Right.WristAbduction;
Data = pi/180*{
.JntPos.Right.WristFlexion,
.JntPos.Right.WristAbduction
};

 T=.JntPos.Right.WristTime;
Type=PiecewiseLinear;

Reaction.Type={Off,Off};

For the trunk segments, should I solve this in a similar way, or is there another (perhaps better) solution?

Best regards,

Frederik

Hi Frederik

The script you have found for the wrist is the correct one.

Concerning the trunk if you have no makers directly attached to the throax segment or pelvis segment you will need alternative ways of driving these.

In the same file as before thee should also be a driver that lock pelvis to the ground all six dof and a driver the PelvisThoraxRotaion three rotations. This would give you 9 extra constrains and effectively the trunk would be entirely driven.

Best regards
Søren

Soren,

many thanks for your answer. In addition, I have one (hopefully) last question: in which file/folder should I add this drivers? The model I started from is the GaitFullBody model.

Thanks!

Frederik

Hi,
this does not matter at all. A good approach may be to just add a file named TunkdriversNew.any or similar.
Best regards,
Sebastian

Sebastian,

you mean that I write in the main folder: “include” TrunkdriversNew.any and that I add a new file in the general folder of my model?

Won’t that create problems with the 2 different studies (optimization and inverse kinematics)?

Frederik

Sebastian,

in addition to my previous post: I made a new file with the drivers, but I get error messages on all the reference points. I changed them into the correct ones, but I still get the same error messages. I’ll attach my folder to this message. Could you have a look into it? I changed everything up to the thorax pelvis rotation driver. I don’t have a clue to what I should change or adjust in order to make the model load.
I have put the new folder under Drivers in the existing model with an #include “ExtraDrivers.any”

Can you provide me with a suggestion in order to fix this?

Many thanks!

Frederik

Frederik,
could you please post your whole model?
Sebastian

Sebastian,

the complete model is attached as a zip-file.

Many thanks in advance!!

Frederik

Hi Frederik,
it loads, No I think you have to adjust the inital position of the pelvis.
Best regards,
Sebastian

Sebastian,

does it load with the extra drivers as wel (ExtraDrivers.any) which are included in the AnyFolder Drivers?
I was already able to load it with a message on the constraints, but when I added the file ExtraDrivers, it does not load anymore…

Frederik

Frederik,
have you used the whole folder? It works fine on my machine.
Best regards,
Sebastian

Sebastian,

it does work on my computer too: I can load the model, but when I start the optimization function, the model produces a series of error messages and is not able to perform the optimization study. Some messages contain information on the lower limbs. (you might check it in the model you sended me) I might exclude both lower legs in the model, but I don’t know wether this is a good way to do so. Secondly, I want to change the model into a model with muscles afterwards. Does this mean that I have to create extra drivers as well or will it work just fine with the existing drivers?

Many thanks again!!

Frederik

Hi Frederic,
no you don’t need new drivers if you add the muscles. I attached a modified model, I excluded legs and one arm. Did you create the correct markers? You created them on the left arm, I would think just based on the displayed markers it should be the right arm, I changed it, but of course I don’t know where they should be located, please check all markers and re-assure it is right or left.
Regards,
Sebastian

Sebastian,

The markers were placed the left arm, it is strange that it looks like they are placed on the right arm. Can there be a difference in the coordinate system of the measurements compared to the coordinate system of the model which explains this?
Anyhow, even with the markers on the right arm, the model still generates a lot of errors if I try to execute the optimization sequence…
I attached the complete error sequence that I get in a txt-file.

I completely don’t onderstand what causes all these problems and errors.

I hope you can help me understanding and solving this!

Many thanks again!!

Frederik

Frederik,
Basically I changed the markers to the right side because I thought it looks unrealistic for a left arm motion… Anyway,here’s a model changed back to left. The motion is strange, but as I have no clue what it should be its impossible to solve without further info. E.g. what is motion of the trunk. Do you have a video or pictures of the motion?
Best regards,
Sebastian

Sebastian,

unfortunately, I don’t have pictures or video from the performed movement. The test person had his arm next to his body and performed a flexion-extension movement in the elbow joint. All other joint were kept in a constant position. The test person was seated on a chair, so there was no movement of the thorax. Normally, these movements were performed with the left arm, however it might be that we made a mistake somewhere and that the movement indeed was performed with the right arm.

I hope this gives you anough information to understand the executed movement.

Frederik

Frederik,
you have to make sure that the markers are placed on the right anatomical spots, close to what it was in the experiment, if you think its a right arm motion, change the markers and check their positions (for this pictures would be very helpful!). Also you should scale at least the bodyheigt, upper and lower arm to fit approx. to the test person, without this its uphill to solve it. And this is obviously even more true if you are not sure where the markers where applied.
Best regards,
Sebastian