standing model

Main Forum
1

Hello
i wish to know

1)how many muscle have been used in standing model example ? how we can know the number of muscles in the model and type of each muscle?

  1. why in bending forward with a few degrees (1-12 Deg) the exerted force on L5 sacrum , L4.L5 , T12.L1 and cervical joint is lower than Standing?( i did not change the example)

Best regards

2

Hi,

  1. About 820. You can compute this by using ObjSearch/ObjSearchRecursive function for example. You could also take a look at the BodyPartSetup and see which body parts and muscle type were used - in the case of the standing model these are SimpleMuscles.

  2. I have just checked and the reaction forces decrease in those joints within a small range of angle values, this is true. However, they achieve a minimum and start to grow later on. This can be interpreted as that our standing straight position is close, but not optimal for the lumbar spine joints. If you subject the model to higher flexion - this will change.

Best regards,
Pavel

3

hi

i wanted to ask in standing model in v5 how the abdominal pressure is modeled? i mean if we have considered this pressure in this model or no? for instance flexion in standing model?

thanks alot

4

Yes, it is included in the Standing Model. You can read about how it works on the wiki:
AbdominalPressureModel
Regards,
Pavel

5

thanks a lot for your answer and attention
here i paste some lines of an article and then ask my question:
" if lumbar curvature in the erect standing and fully flexed (toe-touching) postures are denoted 0% and 100% flexion respectively, then it is apparent that many common postural habits serve to position the lumbar spine in moderate flexion. standing upright increase lumbar lordosis by approximately 2 deg per lumbar level compered to the curvature of an unloaded cadaver spine."

RECENT ADVANCES IN LUMBAR SPINAL MECHANICS (clinical biomechanics)

i wish to know standing model in software is fully erect state of spine? or it has a little flexion?
and why in flexion and extention , mediolateral force change in large ranges?sudden changes happen from -20 to 50 (deg by deg)

best regards

6

Hi,

Looks like you have some lateral bending or axial rotation - please check the drivers. As well as that - the drivers will show whether it is an upright posture or not. 0 - in flexion/extension should correspond to a standing straight person.

Regards,
Pavel

7

Hello
i have a problem with runing inverse dynamics in standing model .
i have changed the angles like this:
PelvisThoraxExtension=-30
[SIZE=3]GlenohumeralFlexion =50;
[/SIZE] and loads in two hands:
[SIZE=3]
AnyVec3[/SIZE] Hand = {0.000, -10.000, 0.000};
after running the inverse dynamics i receive this error
OBJ.MCH.KIN3

which imlies that initial conditions have problem.
would you help me to solve this problem? why i recieve this msg?

thanks alot

8

Hi,

I could not reproduce the problem. Please make sure that you use intact repository and please specify your AMS version.

But the problem seems to be in the kinematics - please check the model view how the model looks like.

Regards,
Pavel

9

Hi!
how can I model spring and 3D external segments(such as rectangular cube)
in anybody modeling system! :confused:
I wan’t to model PLAD(personal lift asist device) in anybody!
If you know about PLAD please help me for modeling that! :frowning:
It’s really necessary for me!
thanx a lot!!!

10

Hi,

In the “Application\Examples” folder of the repository you could find a model called “StandingLift”. This is a model of a man lifting a 10 pounds box. You could use this model as a start.

To model a spring you can refer to AnyForce/AnyForce3D class and make it a function of some kinematic measures. A simple example:


  AnyFloat Stiffness = 15;
  
  AnyForce SpringForce = {
    AnyKinMeasure &l = Main.MyModel.myKinMeasure;
    F = {l.Pos[0]*.Stiffness};
  };

Regards,
Pavel

11

Hi, thanx for your answers!
Please tell me how can I model 2 pulleys and fix them on the back of standing model? then roll a rope over it? that’s part of the PLAD mechanism.

12

Hi,

I’d like to provide you some suggestions:

1) About external environment modeling
One way is to use CAD software.
You can make your own model in a CAD system and export its geometry by STL file format.
Of course you should extract all mass properties.
And also you have to get the relative reference nodes for the definitions of joints.
All these processes may be time-consuming works.

But if your model doesn’t need to be complex,
you can make your own model using AnyScript.

In the ‘SeatedHuman’ example in the repository, if you open ‘Environment.any’ file, you can see the code for modeling seat.

2) About pulley and wire modeling
In the ‘ArmCurl’ example in the repository, you may be able to find it.
Please look at ‘EnvironmentOptimized.any’ file.
Please be aware of that wire can be modeled by ‘AnyKinSPLine’ class.
But AnyKinSPLine can’t be used as a measurement for drivers.
When you define your own AnyKinSPLine object,
you should designate a wrapping cylinder which corresponds to the pulley.
A pulley can be modeled by ‘AnySurfCylinder’ class and you can draw it by using ‘AnyDrawParamSurf’ class.

And if you would put the tension in the wire, you should use ‘AnyReacForce’ on the AnyKinSPline object.

I hope this may help you.

Best regards,
Moonki

13