1. Akhilesh Jha’s Information & Goals
OpenSim Workshop 1

2. Participant Background and Interests
NextGen Aeronautics, Torrance, CA
- Akhilesh Jha, Lead Engineer, Multiscale Materials Modeling Group
Area(s) of interest:
Modeling of human body as a flexible structure
Developing assistance mechanisms to prevent injuries
Designing energy harvesting systems to help soldier carry more weight
Topics you want to see covered:
I would like to see demonstrations of how to use APIs in order to add, for example, actuators, control law, etc.
Want to know how to add different types of springs to the model, run the static optimization and joint reaction analyses, and make sense of the results.

3. Primary Goal to be Accomplished
What is the problem you want to tackle with OpenSim:
What question/problem do you want to answer/solve with OpenSim?
Would like to study the effect of adding external stiffness to human skeleton
What data/models are you bringing with you?
Will be using the musculoskeletal model given in the OpenSim example files.
What has been the biggest challenge so far?
To run the static optimization problem in the presence of external springs.
What do you hope to complete by the end of the workshop?
Add translational/rotation springs between knee and ankle and see how they affects the muscle activation and joint reaction forces for a given gait cycle.
Change spring constants as a function of time, and perform the static optimization and joint reaction analyses. 3

4. What Simulations were Run?
Static Optimization
Did not work with springs
Inverse Dynamics
Worked
Obtained the Power data
Computed Muscle Control with 2392 Model
Very time consuming
Computed Muscle Control with 2354 Model
Was able to run
Verified the power and moment data
Running the model with stiffness

5. Angle Comparison

6. Angle Comparison

7. Power Comparison

8. Power Comparison