combining normal walking with my forward simulation

[Karishma Sebastian]

Hey,

I am working on a project that deals with analysis of gait pattern for a model with and without load on the back. I have made a complete model with all the muscles,the coordinates,load and forces related to this load. I ran the forward dynamics to generate a simulation for the coordinates(eg. I have a set of values that show a change in the coordinates of the lower back, hip,pelvis etc.) but this does not include walking.

I don't have experimental data for a person walking with the load on the back(i.e the one with marker location and values), But i have coordinates of a normal person walking without a load. I want to combine the 2 results(forward dynamics result and the normal motion file) so that i get overall effects of the person walking with a load. Is a there a way to do it? Or is it that i can study the motion of a person with load only using experimental data and inverse kinematics? Can you clarify my doubt and guide me to some tutorial where i can know how to combine these results?

[jimmy d]

From your description, it is not clear how you are trying to approach your problem. You can't have a valid simulation by taking the normal walking data and adding extra mass to the model- the reaction forces won't match the accelerations and masses. If you want to study the effect of load on walking, you will need to collect experimental data to do it.

[Karishma Sebastian]

Thank you so much. I thought so too but wanted to make sure.
I need help.

I have designed a bag that is different from other bags. This design equally distributes load on the shoulders and hip rather than the conventional design where more load is seen distributed on the shoulders. I have the data for the amount of force acting on the shoulders and hip for both kinds of bags.

My problem statement: I want to prove that my design is better compared to the other based on fiber force or metabolic cost or both.

I don't have experimental data. I also read through "Simulated Assistive Devices for Loaded Walking" given in the opensim website where they have used their own assitive device as actuators and an experimental data already available in opensim. I could follow the same method but my device is passive. Opensim is the best simulation software to analyse this kind of problems so i would like to use it. Please help me with the ways by which i can approach this problem. I would be really grateful.