Integrating structure and control design using tensegrity paradigm

Abstract

For centuries researchers have been pushing the boundaries of their respective technical domains, but it is only a few decades ago that research started taking its dig on system design theory. A system design theory encapsulates all individual components design and their simultaneous optimization, i.e., it provides a complete framework to design the structure. The approach behind this research is to make small steps in structure design, dynamic models, information architecture, and control design with some free parameters and then finally optimize those free parameters in a wholesome design approach to meet some specified performance. The author uses tensegrity design models to integrate structure and control design due to the various advantages mentioned further. This dissertation first makes three contributions to the study of tensegrity structures and then provides a system design theory to integrate structure and control design using the tensegrity paradigm. The first part of the dissertation provides a detailed study of the minimum mass tensegrity structures designed to take compressive loads, namely, D-bar and T-bar structures. These design studies consider both local and global failures in designing the optimal configuration (optimal complexity, angle, and cross-sectional area) for both D-bar and T-bar structures. The formulation developed here provides a general methodology to avoid global buckling failures for any class-k tensegrity structures. The proposed research provides different approaches to design a structure based on optimizing mass, stiffness, or mechanical energy stored in a tensegrity structure. The second part of this research work provides accurate dynamic models of axially loaded members forming any general tensegrity structure. The formulation develops a second-order matrix differential equation to perform dynamic simulation of tensegrity structures with massive strings and rigid bars. The dynamics models for novel gyroscopic tensegrity systems are also developed, which adds an extra degree of freedom to the control of the structure. A Matlab based tensegrity dynamics simulator is another outcome of this research. ACKNOWLEDGMENTS I would like to thank my advisor Prof. Robert E. Skelton for his guidance, support, and for giving me the opportunity to work for him. He accepted me with my limited knowledge of controls and no knowledge of tensegrity structures and taught me everything. I feel honored to have them as my advisor. He taught me how to think critically and scientifically during our various research discussions throughout the years. His perspective and passion for research has inspired me and will shape my career in years to come. I am also grateful to Judy Ma'am for making me feel like a family. I would also like to thank Dr. Manoranjan Majji for all the helpful discussions and for having a positive and friendly attitude towards every research topic we discussed. This dissertation could not have been successfully completed without his guidance and help over the years. I would also ...

Robust Shape Control of Gyroscopic Tensegrity Robotic Arm

“…The easy addition of redundant strings enables robust design approaches making the structure well suited for human-robot interaction. A theoretical framework for sensor placements and damage detection in tensegrity structures is a topic of recent research [ [17]].…”