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Georgia Tech
1.
Nadubettu Yadukumar, Shishir.
Input to state stabilizing control Lyapunov functions for hybrid systems.
Degree: PhD, Mechanical Engineering, 2016, Georgia Tech
URL: http://hdl.handle.net/1853/59140
► The thesis analyzes the input-to-state stability (ISS) properties of control Lyapunov functions (CLFs) that stabilize hybrid systems. Systems that are input-to-state stable tend to be…
(more)
▼ The thesis analyzes the input-to-state stability (ISS) properties of control Lyapunov functions (CLFs) that stabilize hybrid systems. Systems that are input-to-state stable tend to be robust to modeling and sensing uncertainties. This dissertation will show that, given the class of control Lyapunov functions (CLFs), a subset of this class of control Lyapunov functions (CLFs) that input-to-state stabilize the given hybrid system, exists. These functions are called the input-to-state stabilizing control Lyapunov functions (ISS-CLFs). As an application, these ISS-CLFs are constructed for bipedal robots, which belong to a special class of hybrid systems: systems with impulsive effects. Bipedal robotic behaviors such as walking, running and dancing are implemented by utilizing variants of input-to-state stabilizing controllers both in simulations and experiments.
Advisors/Committee Members: Ames, Aaron D. (advisor), Vela, Patricio A. (committee member), Egerstedt, Magnus B. (committee member), Rogers, Jonathan (committee member), Ueda, Jun (committee member).
Subjects/Keywords: Control Lyapunov functions; Input to state stability; Hybrid systems; Bipedal robots
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APA (6th Edition):
Nadubettu Yadukumar, S. (2016). Input to state stabilizing control Lyapunov functions for hybrid systems. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/59140
Chicago Manual of Style (16th Edition):
Nadubettu Yadukumar, Shishir. “Input to state stabilizing control Lyapunov functions for hybrid systems.” 2016. Doctoral Dissertation, Georgia Tech. Accessed February 28, 2021.
http://hdl.handle.net/1853/59140.
MLA Handbook (7th Edition):
Nadubettu Yadukumar, Shishir. “Input to state stabilizing control Lyapunov functions for hybrid systems.” 2016. Web. 28 Feb 2021.
Vancouver:
Nadubettu Yadukumar S. Input to state stabilizing control Lyapunov functions for hybrid systems. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/1853/59140.
Council of Science Editors:
Nadubettu Yadukumar S. Input to state stabilizing control Lyapunov functions for hybrid systems. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/59140

Georgia Tech
2.
Diaz-Mercado, Yancy J.
Interactions in multi-robot systems.
Degree: PhD, Electrical and Computer Engineering, 2016, Georgia Tech
URL: http://hdl.handle.net/1853/55020
► The objective of this research is to develop a framework for multi-robot coordination and control with emphasis on human-swarm and inter-agent interactions. We focus on…
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▼ The objective of this research is to develop a framework for multi-robot coordination and control with emphasis on human-swarm and inter-agent interactions. We focus on two problems: in the first we address how to enable a single human operator to externally influence large teams of robots. By directly imposing density functions on the environment, the user is able to abstract away the size of the swarm and manipulate it as a whole, e.g., to achieve specified geometric configurations, or to maneuver it around. In order to pursue this approach, contributions are made to the problem of coverage of time-varying density functions. In the second problem, we address the characterization of inter-agent interactions and enforcement of desired interaction patterns in a provably safe (i.e., collision free) manner, e.g., for achieving rich motion patterns in a shared space, or for mixing of sensor information. We use elements of the braid group, which allows us to symbolically characterize classes of interaction patterns. We further construct a new specification language that allows us to provide rich, temporally-layered specifications to the multi-robot mixing framework, and present algorithms that significantly reduce the search space of specification-satisfying symbols with exactness guarantees. We also synthesize provably safe controllers that generate and track trajectories to satisfy these symbolic inputs. These controllers allow us to find bounds on the amount of safe interactions that can be achieved in a given bounded domain.
Advisors/Committee Members: Egerstedt, Magnus (advisor), Wardi, Yorai (committee member), Yezzi, Anthony (committee member), Ames, Aaron D. (committee member), Zhou, Hao Min (committee member).
Subjects/Keywords: Multi-robot control; Human-swarm interactions; Coverage control; Coverage of time-varying density functions; Braids; Multi-robot mixing; Inter-robot interactions; Mixing limit; Symbolic motion planning
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APA ·
Chicago ·
MLA ·
Vancouver ·
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APA (6th Edition):
Diaz-Mercado, Y. J. (2016). Interactions in multi-robot systems. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/55020
Chicago Manual of Style (16th Edition):
Diaz-Mercado, Yancy J. “Interactions in multi-robot systems.” 2016. Doctoral Dissertation, Georgia Tech. Accessed February 28, 2021.
http://hdl.handle.net/1853/55020.
MLA Handbook (7th Edition):
Diaz-Mercado, Yancy J. “Interactions in multi-robot systems.” 2016. Web. 28 Feb 2021.
Vancouver:
Diaz-Mercado YJ. Interactions in multi-robot systems. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/1853/55020.
Council of Science Editors:
Diaz-Mercado YJ. Interactions in multi-robot systems. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/55020

Georgia Tech
3.
Zhao, Huihua.
From bipedal locomotion to prosthetic walking: A hybrid system and nonlinear control approach.
Degree: PhD, Mechanical Engineering, 2016, Georgia Tech
URL: http://hdl.handle.net/1853/56237
► When modeled after the human form, humanoid robots more easily garner societal acceptance and gain increased dexterity in human environments. During this process of humanoid…
(more)
▼ When modeled after the human form, humanoid robots more easily garner societal acceptance and gain increased dexterity in human environments. During this process of humanoid robot design, research on simulated bodies also yields a better understanding of the original biological system. Such advantages make humanoid robots ideal for use in areas such as elderly assistance, physical rehabilitation, assistive exoskeletons, and prosthetic devices. In these applications specifically, an understanding of human-like bipedal robotic locomotion is requisite for practical purposes. However, compared to mobile robots with wheels, humanoid walking robots are complex to design, difficult to balance, and hard to control, resulting in humanoid robots which walk slowly and unnaturally. Despite emerging research and technologies on humanoid robotic locomotion in recent decades, there still lacks a systematic method for obtaining truly kinematic and fluid walking. In this dissertation, we propose a formal optimization framework for achieving stable, human-like robotic walking with natural heel and toe behavior. Importantly, the mathematical construction allows us to directly realize natural walking on the custom-designed physical robot, AMBER2, resulting in a sustainable and robust multi-contact walking gait. As one of the ultimate goals of studying human-like robotic locomotion, the proposed systematic methodology is then translated to achieve prosthetic walking that is both human-like and energy-efficient, with reduced need for parameter tuning. We evaluate this method on two custom, powered transfemoral prostheses in both 2D (AMPRO1) and 3D (AMPRO3) cases. Finally, this dissertation concludes with future research opportunities.
Advisors/Committee Members: Ames, Aaron D. (advisor), Rogers, Jonathan (advisor), Ueda, Jun (committee member), Goldman, Daniel (committee member), Howard, Ayanna M. (committee member).
Subjects/Keywords: Powered prostheses; Bipedal robots; Humanoid robots; Multi-contact; Hybrid systems; Control Lyapunov function; Optimal control; Quadratic programming; Locomotion
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Zhao, H. (2016). From bipedal locomotion to prosthetic walking: A hybrid system and nonlinear control approach. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/56237
Chicago Manual of Style (16th Edition):
Zhao, Huihua. “From bipedal locomotion to prosthetic walking: A hybrid system and nonlinear control approach.” 2016. Doctoral Dissertation, Georgia Tech. Accessed February 28, 2021.
http://hdl.handle.net/1853/56237.
MLA Handbook (7th Edition):
Zhao, Huihua. “From bipedal locomotion to prosthetic walking: A hybrid system and nonlinear control approach.” 2016. Web. 28 Feb 2021.
Vancouver:
Zhao H. From bipedal locomotion to prosthetic walking: A hybrid system and nonlinear control approach. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/1853/56237.
Council of Science Editors:
Zhao H. From bipedal locomotion to prosthetic walking: A hybrid system and nonlinear control approach. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/56237
4.
Grey, Michael Xander.
High level decomposition for bipedal locomotion planning.
Degree: PhD, Aerospace Engineering, 2017, Georgia Tech
URL: http://hdl.handle.net/1853/58713
► Legged robotic platforms offer an attractive potential for deployment in hazardous scenarios that would be too dangerous for human workers. Legs provide a robot with…
(more)
▼ Legged robotic platforms offer an attractive potential for deployment in hazardous scenarios that would be too dangerous for human workers. Legs provide a robot with the ability to step over obstacles and traverse steep, uneven, or narrow terrain. Such conditions are common in dangerous environments, such as a collapsing building or a nuclear facility during a meltdown. However, identifying the physical motions that a legged robot needs to perform in order to move itself through such an environment is particularly challenging. A human operator may be able to manually design such a motion on a case-by-case basis, but it would be inordinately time-consuming and unsuitable for real-world deployment. This thesis presents a method to decompose challenging large-scale motion planning problems into a high-level planning problem and a set of parallel low-level planning problems. We apply the method to quasi-static bipedal locomotion planning. The method is tested in a series of simulated environments that are designed to reflect some of the challenging geometric features that a robot may face in a disaster scenario. We analyze the improvement in performance that is provided by the high- and low-level decomposition, and we show that completeness is not lost by this decomposition.
Advisors/Committee Members: Liu, C. Karen (advisor), Ames, Aaron D. (advisor), Egerstedt, Magnus (committee member), Hauser, Kris (committee member), Zucker, Matt (committee member).
Subjects/Keywords: Humanoid; Bipedal; Locomotion; Planning; Whole body; Kinematics; Quasi-static
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Grey, M. X. (2017). High level decomposition for bipedal locomotion planning. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/58713
Chicago Manual of Style (16th Edition):
Grey, Michael Xander. “High level decomposition for bipedal locomotion planning.” 2017. Doctoral Dissertation, Georgia Tech. Accessed February 28, 2021.
http://hdl.handle.net/1853/58713.
MLA Handbook (7th Edition):
Grey, Michael Xander. “High level decomposition for bipedal locomotion planning.” 2017. Web. 28 Feb 2021.
Vancouver:
Grey MX. High level decomposition for bipedal locomotion planning. [Internet] [Doctoral dissertation]. Georgia Tech; 2017. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/1853/58713.
Council of Science Editors:
Grey MX. High level decomposition for bipedal locomotion planning. [Doctoral Dissertation]. Georgia Tech; 2017. Available from: http://hdl.handle.net/1853/58713
5.
Garcia, Sergio Ernesto.
Coupling of an objective and quantifiable methodology for assessing upper-body movements with virtual reality gaming platforms.
Degree: PhD, Electrical and Computer Engineering, 2017, Georgia Tech
URL: http://hdl.handle.net/1853/58230
► In the physical therapy and rehabilitation field, virtual reality serious gaming systems have been developed to address the problem of non-compliance to perform the recommended…
(more)
▼ In the physical therapy and rehabilitation field, virtual reality serious gaming systems have been developed to address the problem of non-compliance to perform the recommended in-home exercises, which limits greater improvement due to interrupted training. However, existing systems do not fully mimic the interactions between patients and their therapists, since they do not employ assessment of the user's kinematic performance, nor do they provide targeted corrective feedback. As such, the purpose of this dissertation is to fill in the gap by designing, developing, and validating a more robust system that, not only increases users' motivation to comply with their intervention protocols, but also provides the necessary targeted corrective feedback as a function of the objective assessment of the user's kinematic performance. This dissertation presents data to support the claim that our system is a feasible and effective approach for inducing changes in users' kinematic behavior in real-time, thus allowing for the potential to serve as part of various physiotherapy protocols for individuals who have some form of motor skills disorder.
Advisors/Committee Members: Howard, Ayanna M. (advisor), Vela, Patricio A. (committee member), Bhatti, Pamela T. (committee member), Ames, Aaron D. (committee member), Chen, Yu-Ping (committee member).
Subjects/Keywords: Technological rehabilitation; Cerebral palsy; Super pop VR[TM]; Pattern recognition; Upper-body physiotherapy; Reaching kinematics; Kinematic behavior; Instance- and individual-based classification approaches
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Garcia, S. E. (2017). Coupling of an objective and quantifiable methodology for assessing upper-body movements with virtual reality gaming platforms. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/58230
Chicago Manual of Style (16th Edition):
Garcia, Sergio Ernesto. “Coupling of an objective and quantifiable methodology for assessing upper-body movements with virtual reality gaming platforms.” 2017. Doctoral Dissertation, Georgia Tech. Accessed February 28, 2021.
http://hdl.handle.net/1853/58230.
MLA Handbook (7th Edition):
Garcia, Sergio Ernesto. “Coupling of an objective and quantifiable methodology for assessing upper-body movements with virtual reality gaming platforms.” 2017. Web. 28 Feb 2021.
Vancouver:
Garcia SE. Coupling of an objective and quantifiable methodology for assessing upper-body movements with virtual reality gaming platforms. [Internet] [Doctoral dissertation]. Georgia Tech; 2017. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/1853/58230.
Council of Science Editors:
Garcia SE. Coupling of an objective and quantifiable methodology for assessing upper-body movements with virtual reality gaming platforms. [Doctoral Dissertation]. Georgia Tech; 2017. Available from: http://hdl.handle.net/1853/58230
6.
Powell, Matthew Joseph.
Mechanics-based control of underactuated robotic walking.
Degree: PhD, Mechanical Engineering, 2017, Georgia Tech
URL: http://hdl.handle.net/1853/58763
► The proposed research philosophy is to expose the general mechanics of a particular class of bipedal walking robots and then construct controllers which manipulate these…
(more)
▼ The proposed research philosophy is to expose the general mechanics of a particular class of bipedal walking robots and then construct controllers which manipulate these mechanics to achieve stable walking. The class of robots is characterized a lack of feet – the robot's lower leg contacts the ground at a single, unactuated pivot point. Stabilizing this type of robot walking can be challenging: underactuation corresponds to nonlinear dynamics that are not affected by the robot's motors and thus not locally controllable. To date, successful methods of stabilizing these robots have leveraged mathematical properties of hybrid walking models to construct nonlinear optimization problems which solve for stable walking gaits. This dissertation builds upon the hybrid control system approaches by illuminating useful properties of the hybrid mechanics of underactuated walking – namely that the underactuated dynamics correspond to the angular momentum about the support pivot and that angular momentum is conserved about the points of impact between the robot and the ground – which can be manipulated to produce stabilizing controllers without use of nonlinear optimization. The Mechanics-Based Control method is implemented in simulation of a planar five-link biped model and is used to design gaits that are implemented in experiments with the AMBER 3M robot. Extensions of the method provide means of stabilizing more complex legged locomotion behaviors in simulation, such as: underactuated 3D robotic walking and planar footed walking under Zero-Moment Point constraints.
Advisors/Committee Members: Ames, Aaron D. (advisor), Goldman, Daniel (committee member), Rogers, Jonathan (committee member), Vela, Patricio A. (committee member), Young, Aaron (committee member).
Subjects/Keywords: Robotic walking; Humanoids
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Powell, M. J. (2017). Mechanics-based control of underactuated robotic walking. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/58763
Chicago Manual of Style (16th Edition):
Powell, Matthew Joseph. “Mechanics-based control of underactuated robotic walking.” 2017. Doctoral Dissertation, Georgia Tech. Accessed February 28, 2021.
http://hdl.handle.net/1853/58763.
MLA Handbook (7th Edition):
Powell, Matthew Joseph. “Mechanics-based control of underactuated robotic walking.” 2017. Web. 28 Feb 2021.
Vancouver:
Powell MJ. Mechanics-based control of underactuated robotic walking. [Internet] [Doctoral dissertation]. Georgia Tech; 2017. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/1853/58763.
Council of Science Editors:
Powell MJ. Mechanics-based control of underactuated robotic walking. [Doctoral Dissertation]. Georgia Tech; 2017. Available from: http://hdl.handle.net/1853/58763
.