Towards an autonomous small-size humanoid robot: design issues and control strategies

This paper presents the design considerations of a small-size humanoid robot. The design process has revealed much about the several problems, challenges and tradeoffs imposed by biped locomotion. Among them, we here focus on the control of a single leg and its behaviour when assuming a forward motion. The controller is based on simple motion goals taking into account the reaction forces between the feet and the ground. A new method is proposed which appears to be well adapted to the class of problem considered: the use of a fractional-order controller combined with a genetic algorithm for optimal tuning of the control parameters. The control algorithm is tested through several simulations and its robustness is discussed.