The development of a robotic humanoid is one of the recurrent human dreams of all ages. According to the Webster dictionary a robot is a machine that looks like a human being and performs various complex acts (as walking or talking) of a human being.

Currently, there are biped walking robots made by Japanese companies. These humanoids are based on trajectory control (TC) and its stability relies on the zero moment point. These robots have two major drawbacks: high energy consumption and small stability margins (unable to walk in fully unstructured environments). In contrast, Limit Cycle controlled (LC) robots, which exploit the dynamics of the mechanical systems (pendulum behaviour of the swinging leg) show lower energy consumption whereas walking stability is comparable to the TC robots. However, the global stability of the LC can be improved with the addition of inertial sensors, a camera and series-elastic actuators, controlled by a Central Pattern Generator (mimicking the central nervous system) which would enable them to react to perturbations (uneven terrains, stumbling over obstacles). Considering that the starting point of the LC robots was inspired on human gait, this project proposes one step further in the evolution of LC robotics: implementing the recovery reactions from perturbations that can be found in biological systems, e.g. human stumble reaction. Thus, advancing current robotic concepts (Strategic Objective 2.6.1). These new generation robots will keep lower energy consumption than their TC counterparts with improved stability.

The modelling and control of a biped robot will provide further understanding of human gait paving the way for novel actuated orthoses regarded as robotic extensions of the human being: exoskeletons. The adaptation of a powered lower limb exoskeleton will be a breakthrough in the rehabilitation field. It will also provide support devices for ambient assisted living for the ageing society (Strategic Objective 2.6.2).