Inverse dynamic analysis run error

When I run the anybody model, these warning and error occur.

WARNING(OBJ.MCH.KIN6) : Interface.any(215) : GHRot : Close to singular position : Orientation close to Gimbal Lock, i.e., first and third axis of rotation being parallel

Progressing to solve kinematic optimality conditions and hard constraints.

ERROR(OBJ.MCH.MUS4) : AnyMocapModel.any(60) : InverseDynamicStudy.InverseDynamics : Muscle recruitment solver : solver aborted after maximum number of iterations

This is a captured picture at the moment the simulation is stopped.

What does the blue and red line mean?
and what should I fix so that the simulation doesn't stop?

Hi @twosejin

The warning is about the glenohumeral rotation measure being close to a gimbal lock.

The error indicate that you have constraints that can't be fulfilled. From the image it seems that you should look into the markers around the shoulders as their seem quite elevated. Also look at the feet, the blue line is the ground reaction force acting on the nodes under the feet. There does not seem to be many nodes in contact so the model might be to high of the ground.
Here are some useful pointers to alleviate the error

The red line is the resultant GRF at the center of pressure (light blue sphere).

Best regards,

1 Like

I modified Marker protocol for editing shoulder position.
Also, I changed the GRF settiong to:

      FrictionCoefficient = 0.8;
      LimitDistHigh = 0.1;   
      LimitVelHigh = 0.5; 
      LimitDistLow = -0.1;

But still the error occurs.


In my opinion, this posture is not a posture that places a large load on the muscles.
Do you think there is a problem other than the GRF configuration issue?

Hi @twosejin

I agree the posture should not be muscular demanding, but do you experience large muscle forces?
I cant really see any muscles that are over activated in the image?

You should probably try to alter some of the GRF settings to see if the load can be distributed across more nodes under the foot.

Best regards,