Here is software developed for Stanford's ME 485 course. The files here have been adapted for modeling hip-knee-ankle exoskeleton assistance during walking using ideal torque actuators. It is currently implemented to optimize to reduce activations-squared. Metabolic cost can then be calculated from the results of the optimization.

This project utilizes the optimal muscle control framework from De Groote et al 2016: https://simtk.org/projects/optcntrlmuscle which in turn utilizes GPOPS-II optimal control software and adigator. Experimental data and some software adapted from https://github.com/nickbianco/soft-exosuit-design. The model was adapted from Ong et al. 2017 (check confluence page below for full references).

More information on this project can be found at:
https://simtk-confluence.stanford.edu/display/OpenSim/Modeling+Bilateral+Hip-Knee-Ankle+Exoskeleton+Assistance.