Philipp Stratmann Dominic Lakatos Mehmet Can Özparpucu Alin Albu-Schäffer Legged Elastic Multibody Systems: Adjusting Limit Cycles to Close-to-Optimal Energy Efficiency. 436-443 2017 2 IEEE Robotics Autom. Lett. 2 https://doi.org/10.1109/LRA.2016.2633580 db/journals/ral/ral2.html#StratmannLOA17