SimTK: OpenSim: [#1918] weld constraint and ground reaction forces

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Date:
2013-09-11 08:24

Priority:
3

State:
Open

Submitted by:
george rose (georgehtrose)

Assigned to:
Ayman Habib (aymanh)

Summary:
weld constraint and ground reaction forces

Detailed description
Hi. With the help of Mr. Habib we have been able to input our recorded joint angles from a single markered leg when squatting into opensim. We have also created (and attached) another mot file with both legs moving (we copied and pasted the text again and changed the co-ordinates where appropriate to see this would solve our issue). We are still unable to scale the model or to input our ground reaction forces (taken from a force plate under both feet, and also attached) using the external load section of the inverse dynamics tool.When we click 'run' in the GUI and error message pops up in the bottom right corner saying expected error, the matrix is singular. Our second is that we have been unable to use the weld constrain to fix the feet to the floor (at the moment the hips and fixed and feet move upwards). We attempted to this by following the instructions on weld constraints in the user guide. We have attached two mot files, single leg and both legs, a trc file, ground reaction forces, and a model with markers. The aim of this project to test whether changes in pelvic tilt starting angle have any effect on the joint torque at the ankle, knee and hip when squatting. Thank you for taking the time to help us to resolve these issues. Please contact me if you need any more info.
Hi. With the help of Mr. Habib we have been able to input our recorded joint angles from a single markered leg when squatting into opensim. We have also created (and attached) another mot file with both legs moving (we copied and pasted the text again and changed the co-ordinates where appropriate to see this would solve our issue). We are still unable to scale the model or to input our ground reaction forces (taken from a force plate under both feet, and also attached) using the external load section of the inverse dynamics tool.When we click 'run' in the GUI and error message pops up in the bottom right corner saying expected error, the matrix is singular. Our second is that we have been unable to use the weld constrain to fix the feet to the floor (at the moment the hips and fixed and feet move upwards). We attempted to this by following the instructions on weld constraints in the user guide. We have attached two mot files, single leg and both legs, a trc file, ground reaction forces, and a model with markers. The aim of this project to test whether changes in pelvic tilt starting angle have any effect on the joint torque at the ankle, knee and hip when squatting. Thank you for taking the time to help us to resolve these issues. Please contact me if you need any more info.

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Date: 2013-09-24 17:13 Sender: jimmy d George, Could you please repost this issue in the public forum section? This is most likely not a bug so you will get a better response to your issue if the problem is posted there. The bugs section tends to be for development problems so issues similar to yours get missed by people who can help, like myself and others. cheers, -james

Attachments:

Size	Name	Date	By	Download
276 KiB	GRF Data - Copy.mot	2013-09-11 08:24	georgehtrose	GRF Data - Copy.mot
565 KiB	Test_lucasBF5.trc	2013-09-11 08:25	georgehtrose	Test_lucasBF5.trc
539 KiB	Marker model Lucas both legs weld.osim.txt	2013-09-11 08:29	georgehtrose	Marker model Lucas both legs weld.osim.txt
536 KiB	Marker model Lucas.osim	2013-09-11 08:29	georgehtrose	Marker model Lucas.osim
538 KiB	Marker model Lucas both legs.osim	2013-09-11 08:30	georgehtrose	Marker model Lucas both legs.osim
201 KiB	motion both legs.mot	2013-09-11 08:30	georgehtrose	motion both legs.mot
120 KiB	Squat mo lucas.mot	2013-09-11 08:31	georgehtrose	Squat mo lucas.mot

Field	Old Value	Date	By
File Added	534: Squat mo lucas.mot	2013-09-11 08:31	georgehtrose
File Added	533: motion both legs.mot	2013-09-11 08:30	georgehtrose
File Added	532: Marker model Lucas both legs.osim	2013-09-11 08:30	georgehtrose
File Added	531: Marker model Lucas.osim	2013-09-11 08:29	georgehtrose
File Added	530: Marker model Lucas both legs weld.osim.txt	2013-09-11 08:29	georgehtrose
File Added	529: Test_lucasBF5.trc	2013-09-11 08:25	georgehtrose
File Added	528: GRF Data - Copy.mot	2013-09-11 08:24	georgehtrose

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