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Researcher Associate

Munich Institute of Robotics and Machine Intelligence (MIRMI) at the Technical University of Munich

Postdoctoral Researcher

Munich Institute of Robotics and Machine Intelligence (MIRMI)

Senior Technical Writer

VTEX

Software Developer

DeFi Basket

Software Developer

Port.dev (acquired by Commsor)

Fixed-term Lecturer

Universidade de Brasília

Taught classes of Automatic Process Control, Instrumentation of Automatic Process Control, Laboratory of Automatic Process Control, and State-Space Control Theory.

Postdoctoral Researcher

Universidade de Brasília

Content Writer

Byte Papo

Researched and wrote bibliographies of historical computer scientists for the "Uma Byta História" section of Byte Papo podcast.

Translator

Mathigon

Reviewed Portuguese translations of some courses

Editor

Wikipedia, the Free Encyclopedia

Created and improved several articles on control theory and mathematics. My contributions can be seen at https://en.wikipedia.org/w/index.php?title=Special:Contributions/Saung_Tadashi

Doctor of Philosophy - PhD

Universidade de Brasília

Mechatronics, Robotics, and Automation Engineering

Master of Science - MS

Universidade de Brasília

Mechatronics, Robotics, and Automation Engineering

B. Eng.

Universidade de Brasília

Mechatronics, Robotics, and Automation Engineering

Hybrid Kinematic Control for Rigid Body Pose Stabilization using Dual Quaternions

Journal of the Franklin Institute

In this paper, we address the rigid body pose stabilization problem using dual quaternion formalism. We propose a hybrid control strategy to design a switching control law with hysteresis in such a way that the global asymptotic stability of the closed-loop system is guaranteed and such that the global attractivity of the stabilization pose does not exhibit chattering, a problem that is present in all discontinuous-based feedback controllers. Using numerical simulations, we illustrate the problems that arise from existing results in the literature—as unwinding and chattering—and verify the effectiveness of the proposed controller to solve the robust global pose stability problem.

Dual quaternion-based bimodal global control for robust rigid body pose kinematic stabilization

Proceedings of 2017 American Control Conference

A hybrid bimodal controller for rigid body pose stabilization within the group of unit norm dual-quaternions is proposed in this paper. Using two binary logic state variables, this hysteresis-based controller represents a middle term solution between the memoryless discontinuous controller and the fixed-width hysteretic one. The proposed strategy is novel within the dual-quaternions framework and addresses three common difficulties that appears in the literature of pose and attitude stabilization: global stability, robustness against chattering and against unwinding. The efficacy and performance of the proposed controller are illustrated with numerical examples.

Existence of Continuous or Constant Finsler's Variables for Parameter-Dependent Systems

IEEE Transactions on Automatic Control

Finsler's lemma is a classic mathematical result with applications in control and optimization. When the lemma is applied to parameter-dependent LMIs, as such those that arise from problems of robust stability, the extra variables introduced by this lemma also become dependent on this parameter. This technical note presents some sufficient conditions which ensure, without losing generality, that these extra variables can assume a simple functional dependence on the parameters as continuity or even independence. The results allow avoiding an unnecessary use of a more functionally complicated parameter-dependent variable that increases the search computational burden without reducing the conservatism of the solution.

Parameter-Dependent Filter with Finite Time Boundedness Property for Continuous-Time LPV Systems

Proceedings of XVII Latin American Conference on Automatic Control

Uniform versions of Finsler's lemma

Proceedings of the 54th IEEE Conference on Decision and Control

Finsler's lemma and its variants are used extensively in control and optimization literature. Although there are several variants of this lemma, it can be summarized as an equivalence of a quadratic inequality with a linear constraint to a linear matrix inequality (LMI) with possibly more extra variables than the original problem. When applying Finsler's lemma to problems that depends of a parameter, the extra variables stemming from the use of Finsler's lemma can also be dependent of this parameter. In this paper it is investigated when these extra variables can assume a simple structure without loss of generality and some sufficient conditions that guarantees this assumption are given. These sufficient conditions can be applied when investigating parameter dependent LMIs that emerge, for instance, when dealing with the robust stability of systems with polytopic uncertainty.

Projeto EDUBOT

Anais da V Mostra Nacional de Robótica

Finite time boundedness and stability analysis of discrete time uncertain systems

Proceedings of the 54th IEEE Conference on Decision and Control

In this paper the problems of finite time boundedness and stability of uncertain systems in discrete-time are addressed. By using the Finsler lemma, novel parameter dependent linear matrix inequalities analysis conditions are designed. These conditions can be efficiently solved using a homogeneous polynomial relaxation procedure and readily available numerical solvers. In the numerical examples section, it is shown that the proposed finite time conditions are less conservative than others linear matrix inequality based conditions proposed in the literature.

A new condition for finite time boundedness analysis

Journal of the Franklin Institute

In this paper, a new condition for finite time boundedness analysis is presented. Firstly, a brief discussion of the available conditions found in the literature and comparisons between them regarding computational efficiency and conservatism are presented. Then, a new condition expressed in terms of linear matrix inequalities (LMIs) is derived using Finsler׳s lemma. The proposed condition is proved to be less conservative than LMI conditions previously presented in the literature, and its efficiency is illustrated with numerical examples.

Homogeneous polynomially parameter-dependent state feedback controllers for finite time stabilization of linear time-varying systems

Proceedings of the 2013 European Control Conference

This paper investigates the problem of parameter-dependent state feedback control of continuous-time systems in the context of finite time stability. The controller is designed in order to guarantee that the closed-loop system is finite time stable. The system is considered time varying with the parameters modeled within a unit simplex. The design conditions obtained by means of Lyapunov functions are expressed as linear matrix inequalities. The finite time stability is assessed by using homogeneous polynomially parameter-dependent state feedback gains with arbitrary degree g. LMI relaxations are proposed based on Pólya's theorem. A controller is obtained by the solution of a factibility problem and the effect of the relaxation procedures analyzed by an optimization problem. Numerical examples are provided.

Finite time robust filtering for time-varying uncertain polytopic linear systems

Proceedings of the 2013 European Control Conference

In this paper, the problem of robust filter design for uncertain continuous-time systems is investigated in the context of finite time stability. The filter is obtained in order to guarantee that the augmented system is finite time stable. The system is considered time varying with the parameters modeled by a polytope. The design conditions obtained by means of Lyapunov functions are expressed as linear matrix inequalities. A complete order filter is obtained by the solution of a factibility problem. A numerical example is provided.