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Start Over Author "Tam W. Nguyen" Topic passivity
3 results on '"Tam W. Nguyen"'

1. Distributed Dynamic Reference Governor for Constrained Semi-Autonomous Robotic Swarms with Communication Delays and Experimental Verification

Author

Aditya Wildan Farras, Takeshi Hatanaka, Tam W. Nguyen, Riku Funada, Junya Yamauchi, and Masayuki Fujita

Subjects
semi-autonomous robotic swarms, reference governor, communication delays, distributed optimization, passivity, Control engineering systems. Automatic machinery (General), TJ212-225
Abstract

This paper investigates constrained semi-autonomous robotic swarms in the presence of inter-robot communication delays. The objective is that all robots converge to the optimal point related to the reference given by a human operator without violating the constraints. In the presence of constraints, directly applying the human reference may make the system violate constraints. We thus apply a reference governor which suitably modifies the reference to avoid constraint violations. Due to the limited access of global information, we present a passivity-based distributed reference governor scheme. However, the presence of the communication delays could cause instability of the system. To integrate communication delays into the passivity paradigm, a passivation technique using the scattering transformation is implemented in the communication path. Based on passivity theory, we prove the convergence of the estimated states of the reference governor to the optimal solution. The simulations and experiments demonstrate the effectiveness of the proposed solution.

Published
2019
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2. A Passivity-Based Distributed Reference Governor for Constrained Robotic Networks * *This work is supported by EM-EASED, FRIA, and JSPS KAK- ENHI Grant Number JP15H04019. The stay of Tam Nguyen in Tokyo Institute of Technology has been supported by the Erasmus Mundus EASED programme (Grant 2012-5538/004-001) coordinated by CentraleSupélec

Author

Emanuele Garone, Masayuki Fujita, Tam W. Nguyen, Takeshi Hatanaka, and Mamoru Doi

Subjects
Scheme (programming language), 0209 industrial biotechnology, Mathematical optimization, Computer science, Passivity, Estimator, 02 engineering and technology, State (functional analysis), 020901 industrial engineering & automation, Control and Systems Engineering, Control theory, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Gradient descent, computer, Hamiltonian (control theory), computer.programming_language
Abstract

This paper focuses on a passivity-based distributed reference governor (RG) applied to a pre-stabilized mobile robotic network. The novelty of this paper lies in the method used to solve the RG problem, where a passivity-based distributed optimization scheme is proposed. In particular, the gradient descent method minimizes the global objective function while the dual ascent method maximizes the Hamiltonian. To make the agents converge to the agreed optimal solution, a proportional-integral consensus estimator is used. This paper proves the convergence of the state estimates of the RG to the optimal solution through passivity arguments, considering the physical system static. Then, the effectiveness of the scheme considering the dynamics of the physical system is demonstrated through simulations and experiments.

Published
2017
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3. A Passivity-Based Approach for Constrained Mobile Robotic Networks

Author

Mamoru Doi, Emanuele Garone, Tam W. Nguyen, Masayuki Fujita, and Takeshi Hatanaka

Subjects
0209 industrial biotechnology, Engineering, Robot kinematics, business.industry, 020208 electrical & electronic engineering, Passivity, Stability (learning theory), Mobile computing, Mobile robot, 02 engineering and technology, Constraint satisfaction, Feedback loop, System dynamics, 020901 industrial engineering & automation, Control theory, 0202 electrical engineering, electronic engineering, information engineering, business
Abstract

This paper presents a strategy for the position control of mobile robotic networks subject to geometric con- straints. The main idea of this paper is to show that passivity arguments can be used to ensure both stability and constraint satisfaction. It is shown that it is possible to pre-stabilize the system dynamics with a proportional-integral consensus estimator and a proportional feedback loop which make use of passivity arguments. Then, the very same passivity arguments are used to ensure constraint satisfaction, using a set-invariance based Reference Governor. Simulations and experiments are carried out to demonstrate the effectiveness of the proposed solution.

Published
2016

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