Robots have evolved impressively since the 3-D manipulator built by C.W. K- ward (1957) the two little electromechanical turtles Elmer and Elsie [Walter 1950 Walter 1951] and the ?rst mobile robots controlled by comp- ers Shakey [Nilsson 1984] CART [Moravec 1979 Moravec 1983] and - lare [Giralt et al. 1979]. Since then we have seen industrial robot manipu- tors working in car factories automatic guided vehicles moving heavy loads along pre-de?ned routes human-remotely-operated robots neutralising bombs and even semi-autonomous robots like Sojourner going to Mars and moving from one position to another commanded from Earth. Robots will go further and further in our society. However there is still a kind of robot that has not completely taken off so far: autonomous robots. Autonomy depends upon working without human supervision for a considerable amount of time taking independent decisions adapting to new challenges in dynamic environments interacting with other systems and humans and so on. Research on autonomy is highly motivated by the expectations of having robots that can work with us and for us in everyday environments assisting us at home or work acting as servants and companions to help us in the execution of different tasks so that we can have more spare time and a better quality of life.