Design of a Robot Photovoltaic Power Supply System G. TINA, G. GOZZO, P.ARENA, L. PATANE’ e S. DE FIORE Dipartimento di Ingegneria Elettrica, Elettronica e dei Sistemisti University of Catania Viale Andrea Doria n. 6, 95125 Catania ITALY Abstract: - It is desirable that robots would be, as much as possible, autonomous and self-sufficient. This requires that they can perform their duties while maintaining enough energy to operate. On this regard this paper presents the design and initial results for the power supply of an autonomous robot. Actually Robot design is divided into four primary areas: energy storage, actuation, power and control. But of course there are many relationships among these phases so as matter of fact they have to be made in parallel to optimize the robot especially energetically. In particular a power supply solution that utilizes solar cells and a microcontroller have been chosen to power and control the robot. Finally, initial tests with a probe-loaded robot prototype have demonstrated the feasibility of the solution. Key-Words: - power supply, Photovoltaic system, mobile robot, 1 Introduction There is a large variety of autonomous robots: these can be classified according to their structure, dimensions, maneuverability, main tasks, and so on. In any case, every robot requires a power source to make all its functions, like mobility, control, measures, to mane just the most important. So we have seen that in most cases, robots have a storage system that self-recharges during the mission or at the beginning of the mission, by power stations. This solution increases the robot weight and consumptions, then we are here exploring about the added value, in terms of increased autonomy, of an autonomous power source installed on the robot. In particular, we concentrated our attention on the photocell technology (increase of efficiencies) that cheap (decrease of cost for Wp), as well as on the possibility to use cells on the flexible support, increasing the adaptability degree at any surface of every form. The paper is organised as follows: the state of the art of the photocell application in the robots will be first presented; then a description of the robot and its energy characteristic will be given; subsequently a description of the project of an autonomous photocell system to apply on the robot will be discussed. So far batteries and/or capacitors are used as power sources. The battery supplies only a DC voltage used for the control board of a robot; the capacitor supplies AC voltage for the control of the mobility of a robot by electrical servomotors. The battery uses more time than the capacitors to charge and to discharge energy. There are two strategies for recharging batteries and capacitors: solar panels on the robot and power stations. Gary B. Parker and Richard S. Zbeda [1][2] explain how to power and control the hexapod robot Servobot. Matt Lister and Thomas Salem [3] deal with the DC battery system, since it is the main power source for the robot. Normally this system consists of a combination of switched mode DC power converters. Experimental results show the converter efficiency and voltage ripple at rated load. A discussion of lessons leamed provide insight into the need for proper component selection and placement, printed circuit board fabrication, and ensuring a proper ground plane for successful implementation of a switched mode DC power converter. Albert Esser and Hans-Cristoph Skudenly [4] explain a new system to supply energy for multilink robots. It contains rotatable transformers placed in their joints, thus avoiding the use of movable cables. Mitsuteru Rimura, Nobuki Miyakoshi and Mesahiro Daibou [5] explain a miniature opto- electric transformer, consisting of a p-n junction photocell and a multilayer spiral coil transformer monolithically fabricated on a silicon substrate. It 4th IASME/WSEAS International Conference on ENERGY, ENVIRONMENT, ECOSYSTEMS and SUSTAINABLE DEVELOPMENT (EEESD'08) Algarve, Portugal, June 11-13, 2008 ISBN: 978-960-6766-71-8 239 ISSN: 1790-5095