GRF Prediction
Posted: Thu Jul 08, 2021 6:57 am
Hello everyone,
I have been trying to predict ground reaction forces and moments during walking gait using the zero moment point method described in this paper: https://www.sciencedirect.com/science/a ... 9015005278.
In the paper, they run ID without ground reaction forces applied then transform the resultant forces and moments at the pelvis to the ground. I have been using the raw data values from ID (pelvis tx, ty, tz, tilt, list, rotation) in the calculations described in the paper but am not sure if this is correct. Using the gait2392 model and comparing my calculated results to the provided ground reaction data, my GRF results seem reasonable but GRM do not. I know that residual actuators need to be added to the pelvis for RRA so maybe a similar process is required in this case? I am not very familiar with the concept of residual actuators or how to implement them. If anyone has any suggestions on how to obtain the correct resultant forces and moments at the pelvis, please let me know!
Also, if you know of an easier way to predict GRF, please help! I have mainly been focusing on this paper but also have looked into these methods:
Fluit et al. : https://www.sciencedirect.com/science/a ... via%3Dihub#! - not sure if contact spheres with Hunt-Crossley forces are sufficient or what to do once the contact model is implemented
Contact force static optimization plugin: https://simtk.org/projects/statopt-contact - model won't show up in OpenSim visualizer once contacts are added but no error messages are provided
Thank you so much for your help!
Melanie Hook
melaniehook@vt.edu
I have been trying to predict ground reaction forces and moments during walking gait using the zero moment point method described in this paper: https://www.sciencedirect.com/science/a ... 9015005278.
In the paper, they run ID without ground reaction forces applied then transform the resultant forces and moments at the pelvis to the ground. I have been using the raw data values from ID (pelvis tx, ty, tz, tilt, list, rotation) in the calculations described in the paper but am not sure if this is correct. Using the gait2392 model and comparing my calculated results to the provided ground reaction data, my GRF results seem reasonable but GRM do not. I know that residual actuators need to be added to the pelvis for RRA so maybe a similar process is required in this case? I am not very familiar with the concept of residual actuators or how to implement them. If anyone has any suggestions on how to obtain the correct resultant forces and moments at the pelvis, please let me know!
Also, if you know of an easier way to predict GRF, please help! I have mainly been focusing on this paper but also have looked into these methods:
Fluit et al. : https://www.sciencedirect.com/science/a ... via%3Dihub#! - not sure if contact spheres with Hunt-Crossley forces are sufficient or what to do once the contact model is implemented
Contact force static optimization plugin: https://simtk.org/projects/statopt-contact - model won't show up in OpenSim visualizer once contacts are added but no error messages are provided
Thank you so much for your help!
Melanie Hook
melaniehook@vt.edu