Dear AnyBody community
We want to estimate the metabolic power consumption and the mechanical power of the muscle-tendon unit of the psoas major as accurate as possible during walking. Before using real measurement data, we tried to adapt the 'Plug-in-gait_simple' example so that it would use the 3 element Hill-muscle model for the leg and trunk muscles. Additionally, we would like to calibrate the muscles using the 'Muscle Fiber and Tendon Length Calibration' method. We did this by adding the following lines
#define BM_LEG_MODEL LEG_MODEL_TLEM2
#define BM_LEG_MUSCLES_LEFT MUSCLES_3E_HILL
#define BM_LEG_MUSCLES_RIGHT MUSCLES_3E_HILL
#define BM_TRUNK_MUSCLES MUSCLES_3E_HILL
#define BM_CALIBRATION_TYPE CALIBRATION_TYPE_2PAR
to the 'TrailSpecificData_FullBody.any' below
#define INCLUDE_UPPERBODY ON
We are able to load the model, run the 'ParameterIdentification' study and the 'LoadParameters' and 'MarkerTracking' substudies from the 'RunAnalysis' study. However, when running the 'InverseDynamicsStudy', an overloaded muscle configuration is obtained on the muscles around the shanks of the legs. This ultimately leads to the following error:
> Muscle recruitment solver: solver aborted due to singular KKT matrix
Is there an additional parameter that we should define?
As the 'InverseDynamicsStudy' runs when using the muscle tendon length calibration (CALIBRATION_TYPE_1PAR), our guess is that there is a problem with how we used the 'Muscle Fiber and Tendon Length Calibration' method.
Additionally, we noted that although BM_LEG_MODEL LEG_MODEL_TLEM2 was defined, 'MusMdl3E_2.any' is used for the muscle model (which refers to the TLEM1 according to the comments in the script). When assigning 1 to BM_LEG_MORPHOLOGY (to include 'MusMdl3E_1.any') the model does not load anymore (because of unresolved objects).
We do not have much experience with AnyBody yet. Is there anyone who has already encountered a similar problem/ know how to implement the above properly? Any suggestion to address the problem would be greatly appreciated.
With kind regards