Geometric-Based Optimization Algorithms for Cable Routing and Branching in Cluttered Environments
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Clemson University TigerPrints All Dissertations Dissertations August 2020 Geometric-based Optimization Algorithms for Cable Routing and Branching in Cluttered Environments Nafiseh Masoudi Clemson University, [email protected] Follow this and additional works at: https://tigerprints.clemson.edu/all_dissertations Recommended Citation Masoudi, Nafiseh, "Geometric-based Optimization Algorithms for Cable Routing and Branching in Cluttered Environments" (2020). All Dissertations. 2702. https://tigerprints.clemson.edu/all_dissertations/2702 This Dissertation is brought to you for free and open access by the Dissertations at TigerPrints. It has been accepted for inclusion in All Dissertations by an authorized administrator of TigerPrints. For more information, please contact [email protected]. GEOMETRIC BASED OPTIMIZATION ALGORITHMS FOR CABLE ROUTING AND BRANCHING IN CLUTTERED ENVIRONMENTS A Dissertation Presented to the Graduate School of Clemson University In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy Mechanical Engineering by Nafiseh Masoudi August 2020 Accepted July 21, 2020 by: Dr. Georges M. Fadel, Committee Chair Dr. Margaret M. Wiecek Dr. Joshua D. Summers Dr. Cameron J. Turner Distinguished External Reviewer: Dr. Jonathan Cagan, Carnegie Mellon University ABSTRACT The need for designing lighter and more compact systems often leaves limited space for planning routes for the connectors that enable interactions among the system’s components. Finding optimal routes for these connectors in a densely populated environment left behind at the detail design stage has been a challenging problem for decades. A variety of deterministic as well as heuristic methods has been developed to address different instances of this problem. While the focus of the deterministic methods is primarily on the optimality of the final solution, the heuristics offer acceptable solutions, especially for such problems, in a reasonable amount of time without guaranteeing to find optimal solutions. This study is an attempt to furthering the efforts in deterministic optimization methods to tackle the routing problem in two and three dimensions by focusing on the optimality of final solutions. The objective of this research is twofold. First, a mathematical framework is proposed for the optimization of the layout of wiring connectors in planar cluttered environments. The problem looks at finding the optimal tree network that spans multiple components to be connected with the aim of minimizing the overall length of the connectors while maximizing their common length (for maintainability and traceability of connectors). The optimization problem is formulated as a bi-objective problem and two solution methods are proposed: (1) to solve for the optimal locations of a known number of breakouts (where the connectors branch out) using mixed-binary optimization and visibility notion and (2) to find the minimum length tree that spans multiple components ii of the system and generates the optimal layout using the previously-developed convex hull based routing. The computational performance of these methods in solving a variety of problems is further evaluated. Second, the problem of finding the shortest route connecting two given nodes in a 3D cluttered environment is considered and addressed through deterministically generating a graphical representation of the collision-free space and searching for the shortest path on the found graph. The method is tested on sample workspaces with scattered convex polyhedra and its computational performance is evaluated. The work demonstrates the NP- hardness aspect of the problem which becomes quickly intractable as added components or increase in facets are considered. iii DEDICATION To my best friend, life coach, motivator, and the love of my life, Yasha, for his relentless support and encouragement during my challenges as a doctoral student both inside and outside the lab. This dissertation is also dedicated to my beloved parents Akram and Mansoor for their unconditional love and being my primary teachers. iv ACKNOWLEDGMENT The present effort would have not been possible without the kind support and input of many. I would like to take this opportunity to acknowledge some of the many people who have contributed to the success of my work. First and foremost, I would like to extend my deepest gratitude to my advisor, Professor Georges Fadel for his unwavering support and patience throughout the progress of my research. I truly appreciate the opportunity to work with him as his final Ph.D. student and the input he provided at different stages of my research and academic growth. His insight and advice always helped me find the right direction both in research and my professional development. Professor Fadel always held me to high academic standards and mentored me to take ownership of my work and therefore become a more effective leader and communicator for which I am truly grateful. I gratefully acknowledge the efforts and guidance of my dissertation co-advisor, Professor Margaret Wiecek. Her insight from a mathematician’s point of view was instrumental to the outcome of this research. I would like to express my sincere appreciation to my dissertation committee members, Professors Summers and Turner, and the distinguished external reviewer, Professor Jonathan Cagan, for their invaluable feedback, practical suggestions, and review of my work. My special gratitude goes out to Dr. Summers for all his support and mentorship in helping me become a more effective researcher, instructor, and leader. He was always v willing to take the extra mile in providing advice whenever I felt stuck with a problem in the classes I teach or in my research. Ph.D. studies have enough challenges to discourage a person from keeping up with the path. I, on the other hand, was not left alone in this journey and was fortunate to be joined by my greatest source of encouragement, my husband. Yasha wholeheartedly stood by my side with all his love at every step I took over the course of my studies, never gave up on motivating me when even I was doubting myself and provided insightful suggestions on my research. His continuous support was the key to helping me overcome the hardship of the path. I am deeply grateful for all the love and support I have received from my parents Akram and Mansoor and my sisters Fatima and Bahar during my doctoral studies. Though far away, I always felt them by my side, and I am very fortunate to be a member of this lovely family. I had an amazing opportunity to be a part of a collaborative and vibrant research group, Clemson Engineering Design Applications and Research (CEDAR). To me, CEDAR is a school by itself and this is made possible by the contribution of all the principal investigators (Professors Fadel, Summers, Mocko, and Turner) as well as the graduate students. I take this opportunity to recognize the contribution of my research lab mates at CEDAR (Apurva Patel, Vijay Sarthy, Shubhamkar Kulkarni, Maria Vittoria Elena, Malena Agyemang, Elizabeth Gendreau, Nicole Zero, and Nick Spivey, to name a few) along with the lab alumni: Dr. James Righter, Dr. Meng Xu, Dr. Qing Mao, Dr. Anthony Garland (I appreciate his help with the recursive programming aspects of the vi research), Dr. Ivan Mata (for providing programming tips), Dr. Jingyuan Yan, and Dr. Mo Chen. The scientific discussions we had in CEDAR played an important role in constructing a problem-solving and critical thinking mentality for me. The Mechanical Engineering Department at Clemson University is highly appreciated for the generous financial support made through Teaching Assistantships over three years during my doctoral studies. The experiences I gained from laboratory and classroom teaching had a significant contribution in making me enthusiastic about teaching and deciding to take this route as my future career. I am also grateful to Dr. Todd Schweisinger, my supervisor in undergraduate labs, for his mentorship and support during my teaching appointment and his contribution in offering me a Graduate Teaching Fellowship to teach a junior level mechanical engineering course, Machine Design, so that I could gain more teaching experience as a Ph.D. student. My special thanks go to all the 115 Mechanical Engineering students I had the opportunity to be their instructor during my time at Clemson University who made teaching an enjoyable aspect of my graduate studies. Last but not the least, I acknowledge the help and support of all the ME 2220 Teaching Assistants as well as my friends at Clemson. I am also thankful to the kind staff, Ms. Kathryn Poole and Ms. Trish Nigro, at the Mechanical Engineering Department for the unparalleled service they provide for the graduate students. vii TABLE OF CONTENTS Abstract ............................................................................................................................ ii Dedication ....................................................................................................................... iv Acknowledgment ............................................................................................................. v List of Tables ................................................................................................................... x List of Figures ................................................................................................................. xi Chapter One Introduction ...............................................................................................