Error with Inverse Kinematics
Posted: Wed Feb 11, 2015 1:45 am
Hello all,
I am using an upper body model to simulate a simple throwing motion. After running the scaling and kinematics, I get an error of around .09 meters in the marker which produces the maximum error during the motion itself. Prior to the motion, in the period of time when the subject is in the initial position, that error is less than the 4 cm which opensim says should be achieved to get good results. Does anyone know what the issue might be and also, why would the error go up during the motion itself? I have tried a few things including making sure that the coordinates are constrained to operate within their prescribed range values. I've also tried locking the thorax and turning off markers which I thought were unnecessary to the simulation. All of this did improve my results.
A question related to this, if I can't get the results improved to be within the 2-4 cm threshold during the movement, what effect would that have on computed muscle control and forward dynamics?
Thanks for any help anyone could provide.
Brandon Brown
I am using an upper body model to simulate a simple throwing motion. After running the scaling and kinematics, I get an error of around .09 meters in the marker which produces the maximum error during the motion itself. Prior to the motion, in the period of time when the subject is in the initial position, that error is less than the 4 cm which opensim says should be achieved to get good results. Does anyone know what the issue might be and also, why would the error go up during the motion itself? I have tried a few things including making sure that the coordinates are constrained to operate within their prescribed range values. I've also tried locking the thorax and turning off markers which I thought were unnecessary to the simulation. All of this did improve my results.
A question related to this, if I can't get the results improved to be within the 2-4 cm threshold during the movement, what effect would that have on computed muscle control and forward dynamics?
Thanks for any help anyone could provide.
Brandon Brown