Understanding the RRA pErr file
Posted: Fri Aug 13, 2021 2:14 am
Dear support-team,
I am trying to understand the pErr file (and other files) generated by the RRA (OpenSim 4.2).
From my understanding, the pErr file shows the difference between the IK results and the adjusted kinematics following the RRA simulation.
It would be great if you could clarify some aspects / help with problems:
1) What is the difference between the values in the states.sto file and the Kinematics_q file? Do they both represent the adjusted kinematics? I have noticed that in the states.sto file, there are additional time stamps compared to the Kinematics_q file. (e.g. instead of 0.028, 0.029, 0.030; the time stamps show 0.028, 0.0289, 0.029, 0.0298, 0.030 in the states.sto file).
2) I have tried to calculate the difference between the original kinematics saved in the IK.mot file and the adjusted kinematics saved in the Kinematics_q file and thought this should result in the values saved in the pErr file. I downsampled the Kinematics_q file to my sampling rate of 250 Hz and made sure to adjust the units but my waveforms look quite different compared to what is shows in the pErr file. Is the downsampling inappropriate or am I misunderstanding what the pErr file represents?
Thank you for your help.
Maurice
I am trying to understand the pErr file (and other files) generated by the RRA (OpenSim 4.2).
From my understanding, the pErr file shows the difference between the IK results and the adjusted kinematics following the RRA simulation.
It would be great if you could clarify some aspects / help with problems:
1) What is the difference between the values in the states.sto file and the Kinematics_q file? Do they both represent the adjusted kinematics? I have noticed that in the states.sto file, there are additional time stamps compared to the Kinematics_q file. (e.g. instead of 0.028, 0.029, 0.030; the time stamps show 0.028, 0.0289, 0.029, 0.0298, 0.030 in the states.sto file).
2) I have tried to calculate the difference between the original kinematics saved in the IK.mot file and the adjusted kinematics saved in the Kinematics_q file and thought this should result in the values saved in the pErr file. I downsampled the Kinematics_q file to my sampling rate of 250 Hz and made sure to adjust the units but my waveforms look quite different compared to what is shows in the pErr file. Is the downsampling inappropriate or am I misunderstanding what the pErr file represents?
Thank you for your help.
Maurice