Mar 31 2010
Mr Villaverde’s PhD thesis is entitled, On computational intelligence tools for vision-based navigation of mobile robots.
The researcher studied how the visual navigation of small mobile robots can be improved - these devices being highly useful in the world of work (for example, distribution of mail from table to table) - by applying techniques which have never been tried in robotics previously. It was principally based on an algebraic system that is used in a hyperspectrometric line of research: lattice computing. This involves a system based on series of data (instead of numbers) with concrete internal ordering. As was concluded from the first trials, this technique and certain other ones can be highly useful for enhancing the visual navigation of robots.
Mr Villaverde worked with two types of basic sensors incorporated into mobile robots in order to improve their system of navigation: optic cameras and 3D cameras for range detection. These are the eyes of the robot, and the researcher focused on three primordial questions so these can see correctly: the location of the robot itself, the capacity of the robot to detect its own movements (being able to fix where it is without recourse to analysing external information), and the capacity to build a map (distances, obstacles, and so on) of surroundings previously unknown to it.
Lattice computing and a hybrid system
Thus, the previously mentioned lattice computing and certain other innovative techniques were applied to these three questions. In fact, Mr Villaverde made use of lattice computing, on the one hand, for the self-location of the robot on qualitative maps and, on the other, for the detection of visual markers with optic cameras. This is one of the main contributions of the thesis.
In order to enhance the metric location with 3D cameras, Mr Villaverde applied an innovative hybrid system: combining techniques of evolution and competitive neuronal networks. Evolution techniques are genetic algorithms and neuronal networks are codes that act like the nervous system in humans. So, both simulate human mutations and evolution. The researcher applied these techniques to the 3D cameras and, concretely, to estimating the transformations between 3D views, providing at the same time an estimate of the robot’s movement.
As Mr Villaverde outlined in his thesis, he also carried out a basic experiment, confirming that these innovative applications are, effectively, valid for the visual navigation of robots. He undertook the trials in a shipyard with robots capable of transporting a hose. He chose a shipyard because it has unusual spatial references and, thereby, more testing for detection by robots. It was a first-phase experiment and so the robots did not have to carry out more than some simple functions, but the thesis showed positive results.