69 th International Astronautical Congress (IAC), Bremen, Germany, 1-5 October 2018. Copyright ©2018 by the International Astronautical Federation (IAF). All rights reserved. IAC-18-F1.2.3 Page 1 of 16 IAC-18-F1.2.3 Methods and outcomes of the COMRADE project - Design of robust Combined control for robotic spacecraft and manipulator in servicing missions: comparison between between Hinf and nonlinear Lyapunov-based approaches Pablo Colmenarejo a *, Joao Branco b , Nuno Santos b , Pedro Serra b,j , Juergen Telaar c , Hans Strauch c , Michael Fruhnert c , Alessandro M. Giordano i,d , Marco De Stefano d , Christian Ott d , Matthias Reiner d , David Henry e , Jaroslaw Jaworski f , Evangelos Papadopoulos g , Gianfranco Visentin h , Finn Ankersen h , Jesus Gil- Fernandez h a GMV, Isaac Newton 11, P.T.M. Tres Cantos, E-28760 Madrid, Spain, pcolmena@gmv.com b GMV Skysoft, Av. D. João II, nº 43, Torre Fernão de Magalhães 7º, 1998-025 Lisboa, Portugal, jbranco@gmv.com, nuno.santos@gmv.com, parroz@gmv.com c Airbus Defence and Space, Airbus Allee 1, 28199 Bremen, Germany, juergen.telaar@airbus.com , hans.strauch@airbus.com, michael.fruhnert.external@airbus.com d Deutsches Zentrum für Luft- und Raumfahrt (DLR e.V.), Institute of Robotics and Mechatronics, 82234, Wessling, Germany, Alessandro.Giordano@dlr.de, Marco.DeStefano@dlr.de, Christian.Ott@dlr.de, Matthias.Reiner@dlr.de e Bordeaux University - IMS-LAPS, 351 Cours de la Libération, 33405 Talence, France, david.henry@u-bordeaux.fr f Przemysłowy Instytut Automatyki i Pomiarów (PIAP), Jerozolimskie 202, 02-486 Warsaw, Poland, jaroslaw.jaworski@piap-space.com g NTUA, 9 Heroon Polytechneiou, GR- 15780 Zografou, Athens, Greece, egpapado@central.ntua.gr h ESA/ESTEC, Keplerlaan 1, 2201 AZ Noordwijk, Netherlands, Gianfranco.Visentin@esa.int, Finn.Ankersen@esa.int, jesus.gil.fernandez@esa.int i Department of Informatics, Technical University of Munich, Garching, Germany j Lusofona University of Humanities and Technologies ULHT / ECATI / COPELABS, Lisbon, Portugal * Corresponding Author Abstract Extending life or repairing damaged on-orbit assets is not only a very attractive economic option for satellite operators as it could potentially increase margins for commercial services or increasing delivered value of scientific missions, but it would also help reducing the number of debris objects in space. These types of servicing missions pose technical challenges never faced until now. Of utmost relevance is the autonomous control of several movable devices, whose dynamics are inter-coupled (e.g., spacecraft platform, robotic manipulator, and end-effector), needed to safely and effectively achieve the mission objective. In the frame of ESA-supported COMRADE study, fully combined control (single control system controlling simultaneously all movable devices) is proposed due to its higher improvement potential (propellant saving, performances increase, safety) w.r.t. tele-operation, decoupled and/or collaborative control (the last one characterized by the use of two different control systems for the spacecraft platform and robotic manipulator respectively but, differently to the decoupled version, with information/feedback about what the other control system intends to do). Two independent combined control designs are developed in COMRADE (H∞ and nonlinear Lyapunov-based), and tested. Each of them is applied for both Active Debris Removal (ADR) and servicing/re-fuelling mission scenarios. This paper presents: the processes of scenario analysis and derivation of COMRADE system requirements; a description of the design and setup for a Simulator, which included at its core the selection, prototyping and integration of algorithms for Guidance, Navigation and Control (GNC), Modes Management (AMM) and Failures Detection, Isolation and Recovery (FDIR) (all three together compose the COMRADE system) and the outcomes of the simulation phase of the Verification & Validation process. Keywords: robotic, servicing, debris removal, robust control, compliant control, Envisat Acronyms/Abbreviations AOCS Attitude and Orbit Control System APE Absolute Pointing Error ASSIST hArmonised System Study on Interfaces and Standardisation of fuel Transfer CAM Collision Avoidance Manoeuvre CoM Center of Mass COMRADE Chaser Control Systems Design, Analysis and Trade-off DDVV Design Development Validation and Verification DKE Dynamics, Kinematics, Environment DOF Degree of Freedom