Is the simulation result correct?

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1

I set two fixed points according to the position of Pelvis and AnkleJoint of Right Shank, and fix the human body through StdJoint. The model starts from the ankle dorsiflexion position and simultaneously performs plantarflexion/dorsiflexion and ankle inversion/eversion movements counterclockwise.
SimpleModelTest20230310.zip (7.3 KB)

According to the information I searched, Soleus and Gastrocnemius muscles assist the plantarflexion of the ankle, the Peroneus Brevis muscle assists the plantarflexion and eversion of the ankle, and the Anterior Tibial muscle assists the dorsiflexion and inversion of the ankle joint. But the results I got in the model seem to have some problems.
Activity from Model

I want to ask whether this is reasonable? If it is because of my wrong setting, please tell me how to modify it.

Thank you in advance.
Chen

2

Hi Chen,

Just to be sure of what to look for, can you describe more precisely what you mean by the model seems to have some problems? Are you referring to the peak visible in the Gastrocnemius activity?

Also, I tried to load your model and I am not able to. It seems you are not using the latest AMMR version. Can you please tell me which AMMR and AMS version are you using?

Best regards,
Dave

3

Hi Dave,

I use AMS6.1.1.4986 and AMSR1.6.6. I know this is a very old version. I only make some minor adjustments to the Stand Human model.
I set some BMs of the model as follows.

  #define BM_ARM_LEFT OFF
  #define BM_ARM_RIGHT OFF
  #define BM_LEG_LEFT CONST_LEG_MODEL_OFF
  #define BM_LEG_RIGHT CONST_LEG_MODEL_Leg
  #define BM_TRUNK_MUSCLES CONST_MUSCLES_NONE
  #define BM_LEG_MUSCLES_BOTH CONST_MUSCLES_3E_HILL
  
  #define BM_MANNEQUIN_DRIVER_DEFAULT OFF

I set two fixed points in the environment to connect with pelvis and anklejoint through stdjoint.

AnyFolder Joints = 
{
  AnyStdJoint Seat = 
  {
    AnyRefFrame &ref1 = Main.Model.Environment.GlobalRef.Hpoint;
    AnySeg &ref2 = Main.HumanModel.BodyModel.Trunk.SegmentsLumbar.PelvisSeg;
    Constraints.Reaction.Type = {On,On,On,On,On,On};
  };
  
  AnyUniversalJoint Xuanzhuan = 
  {
    Axis1 = z;
    Axis2 = x;
    AnyRefFrame &ref1 = Main.Model.Environment.GlobalRef.Lpoint;
    AnyRefFrame &ref2 = Main.HumanModel.BodyModel.Right.Leg.Seg.Shank.AnkleJoint;
    Constraints.Reaction.Type = {On,On,On,On};
  };
};

And the settings of drivers are as follows.

AnyFolder Drivers =
{  
  AnyKinEqFourierDriver AnkleDriverRightFlexion={
    AnyKinMeasureOrg &ref1= Main.HumanModel.BodyModel.Interface.Right.AnklePlantarFlexion;
    Type = Cos;
    Freq = 1/5;
    A = {pi/180*{0, 10}};
    B = {{pi/2, 0}};
    Reaction.Type={Off};   
  };
  
  AnyKinEqFourierDriver AnkleDriverRightEversion={
     AnyKinMeasureOrg &ref2= Main.HumanModel.BodyModel.Interface.Right.AnkleEversion;
     Type = Sin;
     Freq = 1/5;
     A = {pi/180*{0,05}};  
     B={{pi/2,0}};  
     Reaction.Type={Off};    
   };
  
  AnyKinEqSimpleDriver PelvisThoraxDriver =   
  { 
    AnyKinMeasureOrg &ref0 = Main.HumanModel.BodyModel.Interface.Trunk.PelvisThoraxExtension; 
    AnyKinMeasureOrg &ref1 = Main.HumanModel.BodyModel.Interface.Trunk.PelvisThoraxLateralBending;  
    AnyKinMeasureOrg &ref2 = Main.HumanModel.BodyModel.Interface.Trunk.PelvisThoraxRotation;  
    
    DriverPos = pi/180*{0, 0, 0}; 
    DriverVel = pi/180*{0, 0, 0}; 
    Reaction.Type = {Off,Off,Off};
    
  }; 
  
  AnyKinEqSimpleDriver NeckJntDriver =  
  { 
    AnyRevoluteJoint &ref0 = Main.HumanModel.BodyModel.Interface.Trunk.NeckJoint; 
    DriverPos = pi/180*{0}; 
    DriverVel = pi/180*{0}; 
    Reaction.Type = {Off};
  };
};

This is the movement of the model.
human
What I want to ask is why the activity of the PeroneusBrevis and TibialisAnterior muscles are similar? Is the result reliable? As far as I know, the role of the PeroneusBrevis and the TibialisAnterior muscle is roughly opposite. For example, I ran MoCapModel in AMMR and got the results.
activity

Thank you in advance.
Chen

4

Hi Chen,

This could be a case of co-contraction because of the movement that you have imposed. It could simply be that your movement results in dorsiflexion and eversion at the same time. This would activate both Tibialis Anterior (for dorsiflexion) and Peroneus Brevis (for eversion). The movement you are simulating is quite different to mocap and also I am not sure if you have any external load acting on your model, unlike in the mocap model where you have ground reaction force. The results in the two models may not be similar in any case.

Hope this helps.
Best regards
Dave

5

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