UNIVERSIDAD POLITÉCNICA DE MADRID ESCUELA TÉCNICA SUPERIOR DE INGENIEROS INDUSTRIALES DESIGN AND EVALUATION OF MODULAR ROBOTS FOR MAINTENANCE IN LARGE SCIENTIFIC FACILITIES PRITHVI SEKHAR PAGALA, MSC 2014 DEPARTAMENTO DE AUTOMÁTICA, INGENIERÍA ELECTRÓNICA E INFORMÁTICA INDUSTRIAL ESCUELA TÉCNICA SUPERIOR DE INGENIEROS INDUSTRIALES DESIGN AND EVALUATION OF MODULAR ROBOTS FOR MAINTENANCE IN LARGE SCIENTIFIC FACILITIES PhD Thesis Author: Prithvi Sekhar Pagala, MSC Advisors: Manuel Ferre Perez, PhD Manuel Armada, PhD 2014 DESIGN AND EVALUATION OF MODULAR ROBOTS FOR MAINTENANCE IN LARGE SCIENTIFIC FACILITIES Author: Prithvi Sekhar Pagala, MSC Tribunal: Presidente: Dr. Fernando Matía Espada Secretario: Dr. Claudio Rossi Vocal A: Dr. Antonio Giménez Fernández Vocal B: Dr. Juan Antonio Escalera Piña Vocal C: Dr. Concepción Alicia Monje Micharet Suplente A: Dr. Mohamed Abderrahim Fichouche Suplente B: Dr. José Maráa Azorín Proveda Acuerdan otorgar la calificación de: Madrid, de de 2014 Acknowledgements The duration of the thesis development lead to inspiring conversations, exchange of ideas and expanding knowledge with amazing individuals. I would like to thank my advisers Manuel Ferre and Manuel Armada for their constant men- torship, support and motivation to pursue different research ideas and collaborations during the course of entire thesis. The team at the lab has not only enriched my professionally life but also in Spanish ways. Thank you all the members of the ROMIN, Francisco, Alex, Jose, Jordi, Ignacio, Javi, Chema, Luis .... This research project has been supported by a Marie Curie Early Stage Initial Training Network Fellowship of the European Community’s Seventh Framework Program "PURESAFE". I wish to thank the supervisors and fellow research members of the project for the amazing support, fruitful interactions and training events. During the project, I had the opportunity to collaborate and work with three different institutions. I wish to thank Ramviyas, Thomas, Mathieu, Pierre, Keith, Bruno from CERN for their constant help in understanding the challenges and different research collaborations. I wish to thank Enrique, Alan, Simon and Eddie from OTL for their valuable insights with regard to the project and the design of connector mechanism. I wish to thank Jouni, Reza, JP, Liisa, Douzi and Aref from TUT and Helmut and Luis from GSI for coordinating the project, discussions and integration of my research work with other fellows. Family and friends have always greatly motivated me in pursuing the research and have made each day into a memorable one. My sincere thanks to all who have helped me in this endeavour. vii Abstract Robots have constantly been moving towards better design and increased predictability in task execution, leading to expanding and increasing robot presence in several fields and applications. One of which is modular robots in large scientific facilities. Modular robots are characterised for not having a fixed configuration but this presents challenges that need to be overcome, to benefit from the large set of advantages. The large scientific facilities presents a challenging environment for robot deployment due to the presence of hazard like ionising radiation and access controlled complicated environment. This thesis explains, the elements of criteria & constraints, hardware design of the robot system and connector mechanism, applications and RAMS (Reliability, Availability, Maintainability and Safety) approach. The basic applications in maintenance tasks is presented along with advanced applications of cooperation, collaboration and integration with planning tool using robot prototype and simulation results. This work extends the use of modular robotic systems to prevent human interventions for maintenance tasks in workspaces with ionising radiation hazard. The different research performed towards improving the RAMS aspects of robot deployment are presented with experiments and results. They focus on mobile robot energy optimisation, force sensorless estimation of external force and energy perspective for bilateral control in telemanip- ulation. The thesis assesses the use of a modular robot system to perform maintenance and inspection tasks such as, remote inspection, manipulation and cooperation with deployed or existing robotic systems inside the facilities. The proposed heterogeneous modular robotic system is evaluated using simulations and the prototype across selected robot configuration to perform tasks. Re- sults obtained, show the advantages and ability of the modular robot to perform the necessary maintenance tasks, as well as its flexibility to adapt and evolve depending on the future needs. Therefore, proving to be a possible solution for inclusion in large scientific facilities to perform maintenance tasks. ix Resumen Los robots se han ido moviendo constantemente hacia un mejor diseño y una mejor predicción en la ejecución de tareas, lo que ha conllevado a un incremento de su presencia en diferentes áreas y aplicaciones. Una de ellas son los robots modulares en grandes instalaciones científicas. Los robots modulares se caracterizan por no tener una configuración fija, pero esto presenta desafíos que hay que superar, para beneficiarse de la amplia serie de ventajas. Las grandes instalaciones científicas se presentan como un entorno difícil para el despliegue de robots debido a la presencia de radiación y un acceso controlado y restringido al sitio de trabajo. En esta tesis se explican los criterios y limitaciones, el diseño del hardware de robots modu- lares así como un conector de módulos, todo esto utilizando el enfoque RAMS por sus siglas en ingles (Fiabilidad, Disponibilidad, Mantenibilidad y Seguridad). Se presentan aplicaciones básicas en tareas de mantenimiento así como aplicaciones avanzadas de cooperación, colabo- ración e integración utilizando resultados obtenidos tanto en simulación como en los prototipos desarrollados. Este trabajo extiende el uso de sistemas robóticos modulares para evitar la in- tervención humana durante tareas de mantenimiento en los espacios de trabajo con riesgo de radiación ionizante. Los diferentes trabajos de investigación realizados con el fin de mejorar los aspectos del RAMS en el despliegue de robots son presentados junto con los experimentos realizados y los resultados obtenidos. Estas mejoras se centran en la optimización del consumo de energía, la estimación de fuerzas externas sin sensores y la perspectiva energética del control bilateral en telemanipu- lación. La tesis evalúa el uso de un sistema robótico modular para realizar tareas de mantenimiento, tales como la inspección remota, la manipulación y la cooperación con otros sistemas robóticos existentes. El sistema heterogéneo propuesto se ha evalúado mediante simulaciones y diferentes prototipos. Los resultados obtenidos, muestran las ventajas y la capacidad de los robots modu- lares para realizar las tareas de mantenimiento, así como su flexibilidad para adaptarse a medida que las necesidades cambian. Por lo tanto, han demostrando ser una posible solución para su inclusión en grandes instalaciones científicas para realizar tareas de mantenimiento. xi xii Contents Acknowledgements vii Abstract ix Resumen xi Contents xiii List of Figures xvii List of Tables xxi Terms and Definitions xxiii 1 Introduction 1 1.1 Goals ....................................... 1 1.2 Motivation ..................................... 1 1.3 Outline ...................................... 2 2 Background and Related Work 5 2.1 Modular robots .................................. 5 2.1.1 History .................................. 7 2.1.2 Advantages of modular robotic system .................. 8 2.1.3 Classifications .............................. 9 2.2 Particle accelerators ................................ 13 2.2.1 Environment constraints ......................... 14 2.2.2 Requirements and tasks .......................... 16 2.3 Radiation protection ................................ 18 3 Heterogeneous Modular Robotic System 23 3.1 Constraints and task requirement ......................... 24 3.2 Modular robot system and ionising radiation ................... 25 3.2.1 Prototype ................................. 26 3.3 System architecture ................................ 30 3.3.1 Robot configurations and simulation ................... 36 3.4 Applications and advantages ........................... 42 3.5 Summary ..................................... 46 3.6 Connector mechanism .............................. 46 xiii xiv Contents 3.6.1 Related work ............................... 47 3.6.2 Requirements to analyse ......................... 48 3.6.3 Previous connectors ........................... 51 3.6.4 Connector mechanism .......................... 53 3.7 Summary ..................................... 56 4 RAMS Approach 59 4.1 Case 1: Energy management for mobile robots ................. 64 4.1.1 Related work ............................... 64 4.1.2 Methodology ............................... 66 4.1.3 Experimental setup ............................ 70 4.1.4 Results and discussions .......................... 73 4.1.5 Summary ................................. 74 4.2 Case 2 : External force estimation using robot model and current sensing .... 76 4.2.1 Requirements ............................... 77 4.2.2 Hypothesis ................................ 79 4.2.3 Preliminary results ............................ 81 4.2.4 Setup ................................... 81 4.2.5 Experiment design ............................ 82 4.2.6 Results .................................