Abstract: Robust and stable real time control of walking robots in contact with objects in their environment is the basic requirement for achieving the tasks, according to requested applications. Interaction with the environment tried to be solved by Raibert, Craig (1981) and Manson (1980) by providing “hybrid control” in force and position, using decomposition into “position sub-space” and “force sub-space”. Compliant motion control, which is essentially the default force control based on position, was suggested by Lawrence (1987), Kazerooni (1990). Salisbury (1980) presented a method to actively controlling the apparent stiffness of the end-effector in Cartesian space. In a similar work, Hogan (1985), Karen (1986) introduced "impedance control", which seeks to establish a desired dynamic relationship between end-effectors' final position of the robot and the contact force. The article presents strategies for improvement of real-time dynamical stability control for a complex structure of hexapod walking robots with six degrees of freedom for each leg of which, three degrees of freedom for positioning and three degrees of freedom for orientation of the foot. Issues for direct and inverse kinematics of the structure of walking robots are analyzed, by determining the first three coordinates of the robot leg joints and by determination of the joint coordinates for the mechanism of orientation. By kinematic "decoupling" of the movement, a separation of positioning control from the orientation control in robot modeling show up. Linear invariants are studied to calculate the position and orientation of the leg support point to determine robot transfer matrix using the Olinde-Rodriques parameters. In terms of dynamic modeling for robot motion control, walking schemes and dynamic control phases are developed. The control system architecture for the dynamic walking robot is presented in correlation with the control strategy which contains many real time control loops: gait timing control which avoids instabilities on the robot motion at landing, damping control aims to eliminate the oscillations that occurs in the single support phase, ZMP compensation control consists in mathematical modeling of ZMP compensator through the spring-loaded inverted pendulums, rotation/advance platform control which allows the central position of the platform to move in the opposite direction, to the inclined transverse plane and control of tilt over the side of safety which prevents the fall of the walking robot in lateral directions, in case of moving on a bumpy field or external forces. In the end, it is designed a multi-microprocessor architecture with multi-tasking control that allows a fast feedback loop for real time robot control with improving stability and flexibility performance.

Brief Biography of the Speaker:
Luige Vladareanu received his M.Sc. degree in electronics from the Polytechnic Institute Bucharest, in 1977. From 1984, scientific researcher of the Institute of Physics and Material Technology, from 1990, team leader of data acquisition systems and real time control systems of the Institute of Solid Mechanics, from 1991, President General Manager of Engineering and Technology Industrial VTC Company. In 1998 he received Ph.D. degree in electronics field from the Institute of Solid Mechanics of Romanian Academy. From 2003, Ministry of Education and Research, executive Department for Financing Superior Education and of Scientific University Research - High Level Expert Consulting for MEC/CNCSIS project, from 2003-2005, member of Engineering Science Committee of Romanian National Research Council, from 2005, Scientific Researcher Gr.I (Professor) of Romanian Academy, from 2009 Head of Mechatronics Department of Institute of Solid Mechanics, Romanian Academy. His scientific work is focused on real time control in solid mechanics applied in robot trajectory control, hybrid position – force control, multi-microprocessor systems for robot control, acquisition and processing of experimental physical data, experimental methods and signal processing, nano-micro manipulators, semi-active control of mechanical system vibrations, semi-active control of magnetorheological dissipaters systems, complex industrial automations with programmable logical controllers in distributed and decentralized structure. He has published 4 books, over 20 book chapters, 11 edited books, over 200 papers in journals, proceedings and conferences in the areas. Director and coordinator of 7 grants of national research – development programs in the last 5 years, 15 invention patents, developing 17 advanced work methods resulting from applicative research activities and more then 60 research projects. In 1985 the Central Institute of Physics Bucharest awarded his research team a price for the first Romanian industrial painting robot. He is the winner of the two Prize and Gold of Excellence in Research 2000, SIR 2000, of the Romanian Government and the Agency for Science, Technology and Innovation. 9 International Invention and Innovation Competition Awards and Gold of World's Exhibition of Inventions, Geneva 2007 - 2009, and other 9 International Invention Awards and Gold of the Brussels, Zagreb, Bucharest International Exhibition. He received “Traian Vuia” (2006) award of the Romanian Academy, Romania's highest scientific research forum, for a group of scientific papers published in the real time control in the solid mechanics. He is team leader of two ANCS (Scientific Research National Agency) funded research projects: “Fundamental and Applied Researches for Position Control of HFPC MERO Walking Robots” from CNCSIS-Exploratory Researches Program and “Complex Modular Automation Systems for Technological Flux Control AUTMPG” from AMCSIT-Innovation Program. He is a member of the International Institute of Acoustics and Vibration (IIAV), Auburn University, USA (2006), ABI/s Research Board of Advisors, American Biographical Institute (2006), World Scientific and Engineering Academy Society, WSEAS (2005), International Association for Modelling and Simulation Techniques in Enterprises-AMSE, France (2004), National Research Council from Romania(2003-2005), etc. He is a PhD advisor in the field of mechanical engineering at the Romanian Academy. He was an organizer of several international conferences such as the General Chair of four WSEAS International Conferences (http://www.wseas.org/conferences/2008/romania/amta/index.html), chaired Plenary Lectures to Houston 2009, Harvard, Boston 2010 and Penang, Malaysia 2010 to the WSEAS International Conferences, is team leader of WSEAS scientific research project: Mechanics & Robotics Systems and is serving on various other conferences and academic societies.