As a part of my MSc. Thesis I submitted a paper concenring the use of trajectory optimisation to assist in the selection of physical parameters in a bipedal robot. Due to the assymetry, complexity and lack of research of rapid acceleration locmotion, it is near impossible to use typical techniques to select parameters such as leg length and gear ratio.
This paper investigated the time optimal locomotion of a bipedal robot and allowed the leg length and gear ratio to be selected. The model used within this paper can be seen below and matches the mechanical design for the platform.
Ultimitely the nominal leg length chosen is 500mm and the gear ratio selected is 5.
The video summary of the trajectories generated from the optimisation problems can be seen below: