Akhilesh Jha’s Information & Goals OpenSim Workshop 1

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.

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

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

Angle Comparison

Angle Comparison

Power Comparison

Power Comparison