H. Ohtake

Kyushu Institute of Information Sciences, Hukuoka, Fukuoka, Japan

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Publications (157)156.32 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: This study presents a sum-of-squares (SOS) approach to stable control and guaranteed cost control of discrete polynomial fuzzy systems. The SOS framework presented in this paper offers a new paradigm over the existing linear matrix inequality (LMI) approaches to discrete Takagi-Sugeno (T??S) fuzzy models. At first, this study, newly introduces a discrete polynomial fuzzy model that is more general and effective than the well-known discrete T-S fuzzy model. With considering the operating domain, stable control design conditions are then derived based on state-dependent Lyapunov functions that contain quadratic Lyapunov functions as a special case. Hence, the design approach discussed in this study could be more general than the LMI design approaches based on quadratic Lyapunov functions. Moreover, this study also discusses a guaranteed cost control design which is carried out by minimising the upper bound of a given performance function. All the design conditions derived in this study can be represented in terms of SOS and are symbolically and numerically solved via the SOSOPT and the SeDuMi, respectively. Finally, the ball-and-beam system is provided as an example to illustrate the utility of the proposed SOS-based design approach.
    IET Control Theory and Applications 03/2014; 8(4):288-296. DOI:10.1049/iet-cta.2013.0645 · 1.84 Impact Factor
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    ABSTRACT: The dependence of a carbon black (CB) dispersion in a tensile-tested specimen of a vulcanized rubber on the compounding ratio of CB was evaluated by terahertz time-domain spectroscopy (THz-TDS). The near broken-out section of the specimens were investigated by THz-TDS, and the distribution of the absorbance in the THz regime, which directly affected by the CB dispersion, was investigated. It was found that the THz image of the CB dispersion in the samples showed a biased distribution between the fixed side and the pulled side of the tensile-tested specimens. It was also found that the difference of the CB dispersion of the both sides was decreased with the CB ratio.
    Lasers and Electro-Optics Pacific Rim (CLEO-PR), 2013 Conference on; 01/2013
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    ABSTRACT: This paper proposes the minimum-type piecewise-Lyapunov-function-based switching fuzzy controller that switches accompanying the piecewise Lyapunov function. By applying this switching fuzzy controller with the minimum-type piecewise Lyapunov function, the relaxed stabilization criterion is obtained for continuous Takagi-Sugeno (T-S) fuzzy systems. Some conditions of the relaxed stabilization criterion are represented by bilinear matrix inequalities (BMIs), which contain some bilinear terms as the product of a full matrix and a scalar. According to the literature, the path-following method is very effective for this kind of BMI problem; hence, it is utilized to obtain solutions of the criterion. Xie et al. in 1997 chose two types (i.e., minimum type and maximum type) of piecewise Lyapunov functions as the Lyapunov function candidates. The reasons for why this study only chooses the minimum-type piecewise Lyapunov function as the Lyapunov function candidate are illustrated. Moreover, the numerical example shows the relaxation of the proposed criterion.
    IEEE Transactions on Fuzzy Systems 12/2012; 20(6):1166-1173. DOI:10.1109/TFUZZ.2012.2196049 · 6.31 Impact Factor
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    ABSTRACT: Piecewise Lyapunov functions and non-quadratic Lyapunov functions have been employed to analyse Takagi-Sugeno (T-S) fuzzy systems for getting relaxed results in the literature. Nevertheless, until now piecewise non-quadratic Lyapunov functions have not been used to design T-S fuzzy control systems. Motivated by the aforementioned concerns, this study utilises the minimum-type piecewise non-quadratic Lyapunov function to design the discrete T-S fuzzy control system. Based on the piecewise non-quadratic Lyapunov function, the switching non-parallel distributed compensation control law is proposed to obtain the relaxed stabilisation criterion. Owing to that some conditions of the proposed criterion are bilinear matrix inequalitiy conditions, the particle swarm optimisation algorithm is applied for finding out the solution of the criterion. An example is provided to illustrate the effectiveness of the proposed criterion.
    IET Control Theory and Applications 08/2012; 6(12):1918-1925. DOI:10.1049/iet-cta.2010.0697 · 1.84 Impact Factor
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    ABSTRACT: This paper presents hovering control of an indoor micro helicopter only using single visual sensor feedback. The control technique is based on the parallel tracking and mapping (PTAM), a kind of visual simultaneous localization and mapping, using a small single wireless camera on the helicopter. The six degree of freedom of the helicopter is detected via the PTAM. The nonlinear dynamics of the helicopter is converted to a Takagi-Sugeno fuzzy model. To design the guaranteed cost (stable) controller, a Takagi-Sugeno fuzzy model-based design is carried out via a linear matrix inequality approach. The hovering control results demonstrate the utility of our approach even though single wireless vision sensor based stabilization is extremely a difficult task in practice.
    Decision and Control (CDC), 2012 IEEE 51st Annual Conference on; 01/2012
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    ABSTRACT: This paper presents fuzzy model-based servo control for a class of nonlinear descriptor systems. In our previous paper, servo control based on error dynamics using error vector and input difference was proposed. In this paper, we extend the servo control technique to nonlinear descriptor systems. The descriptor system can represent larger class of nonlinear systems than the typical state-space models. We show the construction method of fuzzy descriptor system for servo control and derive servo controller design conditions for fuzzy descriptor systems in the form of LMI. Moreover, the servo control which is applicable to switching of target point is also discussed. Design examples illustrate the utility of this approach.
    Fuzzy Systems (FUZZ-IEEE), 2012 IEEE International Conference on; 01/2012
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    ABSTRACT: We have estimated the intensity change in THz pulses emitted from a dipole-type photoconductive antenna as a function of the beam deflection of a pumping laser. The result shows the beam deflection affects the intensity variation of THz pulses comparable to the random errors in the THz-TDS measurements.
    01/2011; DOI:10.1109/irmmw-THz.2011.6104879
  • Hiroshi Ohtake, Kazuo Tanaka, H.O. Wang
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    ABSTRACT: This paper presents servo control for nonlinear systems with constraints on both of inputs and states using the fuzzy model-based control approach. In our previous paper, we proposed servo control with input constraint by introducing input difference between present input and final input. However, it is difficult to constrain both of state of the nonlinear systems and the control input at the same time since time-derivatives of state are used. In this paper, we construct the nonlinear error system based on error vector between state and the target point for servo control. By employing the error system representation and the input difference, servo control with constraints on both of inputs and states can be achieved. We derive LMI conditions for designing servo controller and for constraining control inputs and states. Servo controller with constraints is designed by simultaneously solving servo controller design condition and the constraint conditions. A design example illustrates the utility of this approach.
    Intelligent Control (ISIC), 2010 IEEE International Symposium on; 10/2010
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    ABSTRACT: This paper presents a sum of squares (SOS, for brevity) approach to polynomial fuzzy observer design for polynomial fuzzy systems. First, we briefly summarize previous results with respect to a polynomial fuzzy system and controller that are more general representation of the well-known Takagi-Sugeno (T-S) fuzzy system and controller, respectively. Secondly, we propose a polynomial fuzzy observer to estimate states of the polynomial fuzzy system and derive an SOS condition to design a polynomial fuzzy controller and observer. A key feature of the SOS design condition is that it realizes the so-called separation principle, that is, that a polynomial fuzzy controller and a polynomial fuzzy observer can be separately designed without lack of guaranteeing the stability of the overall control system. The design approach discussed in this paper is more general than the existing LMI approaches (to T-S fuzzy controller and observer designs). In addition, the design condition in the proposed approach can be represented in terms of SOS and is symbolically and numerically solved via the recent developed SOSTOOLS and a semidefinite program (SDP) solver, respectively. To illustrate the validity of the design approach, a design example is provided. The example shows the utility of our SOS approach to the polynomial fuzzy observer-based control.
    Decision and Control, 2009 held jointly with the 2009 28th Chinese Control Conference. CDC/CCC 2009. Proceedings of the 48th IEEE Conference on; 01/2010
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    ABSTRACT: In this study, the piecewise Lyapunov function based switching fuzzy controller is proposed to get a relaxed criterion for the H<sub>∞</sub> control of continuous T-S fuzzy systems. The particle swarm optimization (PSO) algorithm, which is useful for nonlinear optimization problem, is utilized with the LMI tool to get the optimal H<sub>∞</sub> performance due to that some conditions of the criterion are bilinear with the s-procedure parameters. The simulation results have shown the validity of the proposed H<sub>∞</sub> control method.
    Decision and Control, 2009 held jointly with the 2009 28th Chinese Control Conference. CDC/CCC 2009. Proceedings of the 48th IEEE Conference on; 01/2010
  • H. Ohtake, K. Tanaka, H.O. Wang
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    ABSTRACT: This correspondence presents servo and nonlinear model following controls for a class of nonlinear systems using the Takagi-Sugeno fuzzy model-based control approach. First, the construction method of the augmented fuzzy system for continuous-time nonlinear systems is proposed by differentiating the original nonlinear system. Second, the dynamic fuzzy servo controller and the dynamic fuzzy model following controller, which can make outputs of the nonlinear system converge to target points and to outputs of the reference system, respectively, are introduced. Finally, the servo and model following controller design conditions are given in terms of linear matrix inequalities. Design examples illustrate the utility of this approach.
    IEEE Transactions on Systems Man and Cybernetics Part B (Cybernetics) 01/2010; · 3.78 Impact Factor
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    ABSTRACT: This paper presents the stability analysis for polynomial fuzzy systems by utilizing the equality constraints of sum-of-squares (SOS) Program. Recently, T-S fuzzy systems have been extended to polynomial fuzzy systems, in which the consequent parts could be polynomial sub-systems. Moreover, stability and stabilization analyses for polynomial fuzzy systems have been done based on polynomial Lyapunov functions that contain quadratic Lyapunov functions as a special case. Since polynomials exist in the sub-systems and the positive definite matrices of the Lyapunov functions, the linear matrix inequality (LMI) tools are not valid for the polynomial analyses. Instead of LMI tools, SOSTOOLS of Matlab toolbox is applied to solve solutions for the polynomial analyses. The SOS program of SOSTOOLS can solve two kinds of constraints that are equality constraints and inequality constraints. The existing stability and stabilization analyses for polynomial fuzzy systems represent their conditions only in the inequality constraints. This paper analyzes the stability of the polynomial fuzzy systems by polynomial Lyapunov functions, and represents the new stability conditions not only in terms of the inequality constraints but also in terms of the equality constraints.
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    ABSTRACT: The distribution of carbon black (CB) in rubber vulcanizates containing several additives such as carbon black, zinc oxide, etc. was estimated by terahertz time-domain spectroscopy. It was found that the CB distribution could be clearly visualized by this method and the THz measurements indicated high reproducibility.
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    ABSTRACT: This paper presents a sum of squares (SOS) approach for modeling and control of nonlinear dynamical systems using polynomial fuzzy systems. The proposed SOS-based framework provides a number of innovations and improvements over the existing linear matrix inequality (LMI)-based approaches to Takagi-Sugeno (T-S) fuzzy modeling and control. First, we propose a polynomial fuzzy modeling and control framework that is more general and effective than the well-known T--S fuzzy modeling and control. Secondly, we obtain stability and stabilizability conditions of the polynomial fuzzy systems based on polynomial Lyapunov functions that contain quadratic Lyapunov functions as a special case. Hence, the stability and stabilizability conditions presented in this paper are more general and relaxed than those of the existing LMI-based approaches to T-S fuzzy modeling and control. Moreover, the derived stability and stabilizability conditions are represented in terms of SOS and can be numerically (partially symbolically) solved via the recently developed SOSTOOLS. To illustrate the validity and applicability of the proposed approach, a number of analysis and design examples are provided. The first example shows that the SOS approach renders more relaxed stability results than those of both the LMI-based approaches and a polynomial system approach. The second example presents an extensive application of the SOS approach in comparison with a piecewise Lyapunov function approach. The last example is a design exercise that demonstrates the viability of the SOS-based approach to synthesizing a stabilizing controller.
    IEEE Transactions on Fuzzy Systems 09/2009; DOI:10.1109/TFUZZ.2008.924341 · 6.31 Impact Factor
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    ABSTRACT: In this study, the guaranteed cost control of continuous T-S fuzzy systems using piecewise Lyapunov function based switching fuzzy controller is presented. In our previous paper, the switching fuzzy controller, which switches depending on the piecewise Lyapunov function, was proposed. Based on the piecewise Lyapunov function and the switching fuzzy controller, more relaxed guaranteed cost control conditions are obtained. The relaxed conditions are bilinear with the s-procedure parameters. In this paper, the particle swarm optimization (PSO) algorithm, which is useful for the nonlinear optimization problem, is utilized to get the optimal control performance. A design example is provided to illustrate the validity of the design approach.
    Control Applications, (CCA) & Intelligent Control, (ISIC), 2009 IEEE; 08/2009
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    Hiroshi Ohtake, Kazuo Tanaka, H.O. Wang
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    ABSTRACT: This paper presents improved LMI (linear matrix inequality) controller design condition for switching fuzzy model-based control using slack variable approach based on the inverse use of the elimination lemma. In our previous papers, we derived controller design conditions for augmented switching fuzzy model which consists of a switching fuzzy model and a stable linear system. However, in the papers, we have to determine the stable linear system in advance. In this paper, by employing slack variable approach based on the inverse use of the elimination lemma, we derive LMI controller design conditions for the switching fuzzy model without determining the stable linear system in advance. A design example illustrates the utility of this approach.
    American Control Conference, 2009. ACC '09.; 07/2009
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    ABSTRACT: This paper presents a general complex switched network (CSN) model that contains switching behaviors in both its nodes and topology configuration. Stabilization of such directed time-varying CSNs with two types of delays is investigated. The two types of delays consist of the system delay at each node and the coupling time-delay between nodes. Based on the Lyapunov stability theory, delay independent stabilizing conditions for CSNs with both types of delays are obtained via impulsive control. A numerical example is provided for illustration.
    American Control Conference, 2009. ACC '09.; 07/2009
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    ABSTRACT: We propose a novel technique for the generation of high power monocycle terahertz pulse beyond the excitation pulse width limitation. Optical pulse may get modulated by emitted intense THz electric field. This causes excitation pulse compression and consequently gives rise to the enhancement of generation efficiency and its bandwidth. We experimentally demonstrate this chi<sup>(2)</sup> cascaded processes using tilted wavefront excitation beam by LiNbO<sub>3</sub> from Ti:Sapphire and Yb doped fiber laser.
    Lasers and Electro-Optics, 2009 and 2009 Conference on Quantum electronics and Laser Science Conference. CLEO/QELS 2009. Conference on; 07/2009
  • Naohiro Hara, Kazuo Tanaka, Hiroshi Ohtake, H.O. Wang
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    ABSTRACT: We develop a flying robot with a new pantograph-based variable wing mechanism for horizontal-axis rotorcrafts (cyclogyro rotorcrafts). A key feature of the new mechanism is to have a unique trajectory of variable wings that not only change angles of attack but also expand and contract according to wing positions. As a first step, this paper focuses on demonstrating the possibility of the flying robot with this mechanism. After addressing the pantograph-based variable wing mechanism and its features, a simulation model of this mechanism is constructed. Next, we present some comparison results (between the simulation model and experimental data) for a prototype body with the proposed pantograph-based variable wing mechanism. Both simulation and experimental results show that the flying robot with this new mechanism can generate enough lift forces to keep itself in the air. Furthermore, we construct a more precise simulation model by considering rotational motion of each wing. As a result of optimizing design parameters using the precise simulation model, flight performance experimental results demonstrate that the robot with the optimal design parameters can generate not only enough lift forces but a 155 gf payload as well.
    IEEE Transactions on Robotics 03/2009; 25(1-25):79 - 87. DOI:10.1109/TRO.2008.2008736 · 2.65 Impact Factor
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    ABSTRACT: This paper presents a cost-effective design based on sensor reduction for backing-up control of a vehicle with triple trailers. To realize a cost-effective design, we newly derive two linear-matrix-inequality (LMI) conditions for a discrete Takagi-Sugeno fuzzy system. One is an optimal dynamic output feedback design that guarantees desired control performance. The other is an avoidance of jackknife phenomenon for the use of the optimal dynamic output feedback controller. Our results demonstrate that the proposed LMI-based design effectively achieves the backing-up control of the vehicle with triple trailers while avoiding the jackknife phenomenon. More importantly, we demonstrate that the designed optimal control can achieve the backing-up control without, at least, two potentiometers that were employed to measure the relative angles (of a vehicle with triple trailers) in our previous experiments. Since the relative angles directly relate to the jackknife phenomenon, the successful control results without two potentiometers are very interesting and important from the cost-effective design point of view.
    IEEE Transactions on Industrial Electronics 03/2009; DOI:10.1109/TIE.2008.2003218 · 6.50 Impact Factor

Publication Stats

2k Citations
156.32 Total Impact Points

Institutions

  • 2014
    • Kyushu Institute of Information Sciences
      Hukuoka, Fukuoka, Japan
  • 2012
    • Kyushu Institute of Technology
      Kitakyūshū, Fukuoka, Japan
  • 2001–2012
    • The University of Electro-Communications
      • Department of Mechanical Engineering and Intelligent Systems
      Edo, Tōkyō, Japan
    • Chiba University
      • Graduate School of Science and Technology
      Tiba, Chiba, Japan
    • Kobe University
      • Department of Chemistry
      Kōbe, Hyōgo, Japan
  • 2007
    • Boston University
      • Department of Mechanical Engineering
      Boston, Massachusetts, United States
  • 2005–2006
    • Osaka University
      • Department of Biotechnology
      Suita, Osaka-fu, Japan
  • 2001–2006
    • NEC Corporation
      Edo, Tōkyō, Japan
  • 1999–2006
    • Tohoku University
      • • Institute of Fluid Science
      • • Institute for Materials Research
      Japan
  • 1993–2006
    • Hiroshima University
      • • Department of Molecular Biotechnology
      • • Graduate School of Engineering
      Hiroshima-shi, Hiroshima-ken, Japan
  • 1999–2001
    • Institute for Molecular Science
      Okazaki, Aichi, Japan
  • 2000
    • Fukuyama University
      Hukuyama, Hiroshima, Japan
  • 1998
    • National Fisheries University
      Simonoseki, Yamaguchi, Japan