I used GPOPS-II [Matlab Optimal Control Software] to optimize squared torques of one DOF pendulum problem to evaluate GPOPS-II to be used in Human Motion & Control Lab.
I am currently working to optimize 2D gait problem using GPOPS-II. The optimization problem that I am talking about is to find cyclic gait with a prescribed speed and cycle time, minimizing the integral of squared torques. The initial guess is static standing, which was easy to solve. The problem is very nonlinear because of foot-ground contact in the gait model.