I am having problems with my mocap model for a simple lifting and lowering task. The kinematic analysis continues to fail (Error message below). I have tried numerous ways to solve the issue such as altering marker position, starting position etc, however I am unable to solve the problem. Can you please help me debug the model (attached) and supply some advice.
Just to point out, the elbow markers were placed on the lateral epicondyle and the problem occurring seems to be taking place at the arms.
It must be noted that on some occasions the model will work and on other occasions it does not. For instance, the first C3D file (normal lift - file 004) works, second C3D file (semi-stooped lift - file 008) does not work and the third C3D file (stooped lift - file 014) does work. Markers were not altered throughout testing.
Macro command : RunMotionAndParameterOptimizationSequence(5:5)> run
5.0) Kinematics (Operation: Main.Studies.MotionOptimization.Kinematics):
5.0.0) PreOperation (Operation: Main.Studies.MotionOptimization.Kinematics.PreOperation):
18.104.22.168) InitialConditions (Operation: Main.Studies.MotionOptimization.InitialConditions):
22.214.171.124) …Design variables have been updated.
126.96.36.199) …Load-time positions have been re-established.
188.8.131.52) …Kinematic analysis completed. The kinematic constraints have been resolved.
184.108.40.206) …Initial conditions are fully updated.
5.0) Kinematic analysis…
WARNING(OBJ.MCH.KIN6) : C:/U…s/k…n/D…s/A…y/A…o/Body/A…n/Arm/Jnt.any(46) : GHRot : Close to singular position : Orientation close to Gimbal Lock, i.e., first and third axis of rotation being parallel
Failed to resolve kinematic constraints. Newton relaxation too small. (final kin. error = 3.256412E-006)
Constraint no. 98 above error tolerance 0.000001, error = 0.000002.
Constraint no. 99 above error tolerance 0.000001, error = 0.000002.
Constraint no. 238 above error tolerance 0.000001, error = 0.000002.
Constraint no. 245 above error tolerance 0.000001, error = 0.000002.
Constraint no. 246 above error tolerance 0.000001, error = 0.000003.
5.138) …Kinematic analysis terminated
ERROR(OBJ.MCH.KIN3) : C:/U…s/k…n/D…s/A…y/A…o/A…n/E…s/M…g/M…l/Kinematics.any(74) : MotionOptimization.Kinematics : Kinematic analysis failed in time step 138