Difference: OptimizingWalking (13 vs. 14)

Contribution: The authors present a procedure for optimizing the stability and other performance metrics of walking controllers based on the SIMBICON system. They describe a number of biomechanically motivated error terms that aim to discourage unnatural gaits, then minimize the combined error using Covariance Matrix Adaptation to tweak a character's DOF parameters.

Evaluation: The authors run several experiments, describing both quantitative and qualitative results. They compare the resulting walking style with and without the influence of various of their error terms. Helpfully, they quantitatively plot some interesting aspects of walking gaits for a normal SIMBICON implementation, for their optimized controller, and for averaged motion capture data. Finally, they test robustness of the walk on varied body types and terrains, and with random pushes on the character.

Reproducibility: The authors provide significant details on their error term formulae, as well as the values of most of their non-optimized parameters. Additionally, their code implementation is available on the project website. As such, reproduction would not be overly difficult for their solution.

Improvements: Generally speaking, the writing was clear and descriptive. To nitpick one aspect, while the authors provide reasonable and straightforward descriptions of the structure of their error terms, the error thresholds (epsilon's) and error combination weights (w's) are given without any justification. How much hand-tuning was required of these parameters before achieving reasonable results?

-- BenHumberston - 24 Nov 2011