Rafael Kelly has occupied teaching positions at National University of Mexico (UNAM)m University of Nuevo Leon, ITESM, and CICESE Research Center. He has been visiting Professor at the University of Illinois at Urbana-Champaign and INRIA, France. He is the author of more than 130 papers in refereed journals and conference proceedings, most of them devoted to robot control. Professor Kelly is the recipient of many awards and honours among which is the national award of the Mexican Academy of Sciences. He has taught robot control once a year since 1989. Victor Santibanez spent several years at the Hot Roller Mill Department of Altos Hornos de Mexico, at the Electronics Instrumentation Department of of Metalurgica Mexicana Penoles and the Instituto de Automatica Industrial del Consejo Superior de Investigacion Cientifica in Madrid. He has taught robot control and adaptive control twice each year at ITL Mexico since 1997. He is also author of about fifty journal and conference papers as well as a book chapter in adaptive control of manipulators. Antonio Loria has been a research fellow at the University of Twente, NTNU Norway and UCSB, California. Currently, he has a tenure position as Associate Researcher with the National Centre for Scientific Research (CNRS), France. He is author of more than seventy scientific journal and conference papers as well as four book chapters in control theory; of these publications, more than 20 are on robot control. He is co-author of Passivity-based Control of Euler-Lagrange Systems: Mechanical, Electrical and Electromechanical Applications by R. Ortega, A. Loria, P.J. Nicklasson and H. Sira-Ramirez (1-85233-016-3).