Nan showing up in COP computation post-MocoTracking simulation with foot-ground contact.

[stingjp]

Problem: MocoTrack, with both coordinate and GRF tracking. Using foot-ground contact in a simple OpenSim model. After getting a solution, extract the GRFs from using the osim.createExternalLoadsTableForGait() method. The values appear to show up as Nan during periods where the foot is not in contact with the ground (possibly a divide by zero issue). Working in OpenSim version: 4.4.1

Attaching the:

• script: py_overground_3ActMet_ST.py
• model: mk12_rv1_dgf_met.osim
• coordinates: ./expData/2D2Darms/27_IK_nat_mk12_rv1_1.mot
• GRF files: grf_walk_nat_1.xml & ./expData/nat_1_GRF.mot
• sample solution: 3ActMetST_2D3D_OG_muscles_Tracking_solution__Halfgaitcycle.sto & 3ActMetST_2D3D_OG_muscles_Tracking_solution_FullStride.sto
• GRF solution file: 3ActMetST_2D3D_OG_muscles_Tracking_solutionGRF_FullStride.sto

mocoIssue.zip