Kyoto University Logo School of Informatics Logo

Yoshito Ohta

Professor
Control Systems Theory Group
Department of Applied Mathematics and Physics
Graduate School of Informatics
Kyoto University
Japanese Page

Research

Research interests

My research interests include control system design, system identification, and networked control systems. The following are specific topics.

Control of power networks

The increase of renewable energy sources raise problems for control of power networks. For example, power generation and consumption should be balanced, the voltage and the frequency should be kept within the prescribed range, and the power generation and distribution should be efficiently carried out. The aim of the study is to cope with these problems and to develop control techniques to ensure the quality of electric power in the presence of variable renewable energy.

Control of electronic power devices such as grid-tie inverters and DC-DC converters is studied in this research work. We apply robust control techniques and improve control performance of the devices. Grid-tie inverters are a device that sends electrical power generated by photovoltaic (PV) cells or wind firms into AC power transmission line. We design the current control loop appropriately to satisfy the FRT (fault-ride-through) capabilities. DC-DC converters are a device that produces desired DC voltage. We design a controller for DC-DC zeta converters that can function both step-up and step-down operations.

The voltage regulation at the connection point is necessary to deal with inverse power flow caused by PV generation. We propose a distributed algorithm to control both active power and reactive power to keep the voltage within the allowable range. The algorithm can be applied to both residential solar systems and PV power plants using a\real-time pricing strategy.

System modeling and identification

System identification is a fundamental research area studying modeling of dynamical control systems. Currently, a continuous-time system identification method based on system transformation and the Bayesian system identification approach are under investigation.

Generalized orthonormal basis functions are a special class of orthonormal basis that induces continuous-time to discrete-time system transformation. This extends to stochastic systems having random processes as inputs and outputs. We propose a continuous-time system identification algorithm based on the transformation.

The Bayesian approach is applied to system identification of an FIR (finite impulse response) model. The impulse response is estimated using the maximal likelihood method. Choosing suitable kernels that capture the dynamics of the plant is essential. In this research, we investigate the kernel based on the generalized orthonormal basis functions. Also we study the empirical Bayes approach for the hyper-parameter selection.

Networked control

The aim of this research is to derive fundamental limitations of networked control systems. Networks are modeled by channels having communication constraints. The main focus of the research is to derive achievable control performances under the given communication constraints.

The state estimation problem and the disturbance rejection problem for networked control systems are studied using the information theoretic approach that can handle both Gaussian variables and bounded variables.


Publications

2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003-1984

2018

  • Hidenori Shingin, and Yoshito Ohta, “ Reduction of state variables based on regulation and filtering performances, “ Automatica, vol.92, pp.143--154, 2018.
  • Yoshito Ohta, and Paolo Rapisarda, “ System Transformation Induced by Generalized Orthonormal Basis Functions Preserves Dissipativity, “ MTNS 2018, Hong Kong, July, 2018. (accepted)
  • Man Zheng, and Yoshito Ohta, “ Positive FIR System Identification using Maximum Entropy Prior. “ 18th IFAC Symposium on System Identification Stockholm, Sweden, July 9-11, 2018. (accepted)

2017

  • Yuta Okumura, Kenji Kashima, and Yoshito Ohta, “ Iterative path integral approach to nonlinear stochastic optimal control under compound Poisson noise, “ Asian Journal of Control, vol.19, no.2, pp.781--786, 2017.
  • Kenji Hirata, Hikaru Akutsu, Akihiro Ohori, Nobuyuki Hattori, and Yoshito Ohta, “ Decentralized voltage regulation for PV generation plants using real-time pricing strategy, “ IEEE Transactions on Industrial Electronics, vol. 64, pp.5222--5232, 2017.
  • Kentaro Ohki, Takuya Kakehashi, Hideharu Sugihara, Kenji Kashima, and Yoshito Ohta, “ Analyzing the Effects of Transmission Line Fault on the Stochastic Model Predictive Controlled IEEE 30-Bus System with Uncertain Environment, “ 2017 IEEE CCTA, pp.1064--1069, Kohala Coast, Hawaii, Aug 27-30, 2017.
  • Hidenori Shingin, and Yoshito Ohta, “ SNR analysis for linear quadratic control over Gaussian channels with feedback, “ The 20th IFAC World Congress, pp.6403--6409, Toulouse, France, July 9-14, 2017.
  • Takaaki Kondo, Seiji Yamaoka, and Yoshito Ohta, “ A hyper-parameter estimation algorithm in Bayesian system identification using OBFs-based kernels, “ The 20th IFAC World Congress, pp.14727--14732, Toulouse, France, July 9-14, 2017.
  • Hikaru Akutsu, Kenji Hirata, Akihiro Ohori, Nobuyuki Hattori, and Yoshito Ohta, “ Decentralized active and reactive power control for PV generation plants using real-time pricing strategy, “ 2017 American Control Conference, pp.2761-2766, Seattle, USA, May 24-26, 2017.

2016

  • Yili Dong, and Yoshito Ohta, “ Attitude synchronization of rigid bodies via distributed control, “ The 55th IEEE Conference on Decision and Control, pp. 3499-3504, Las Vegas, December 12-14, 2016.
  • Hafez Sarkawi, and Yoshito Ohta, “ Optimal state-feedback and proportional-integral controller performance comparison for Dc-Dc Zeta converter operating in continuous conduction mode, “ SICE Annual Conference, pp. 448-451, Tsukuba, Japan, September 20-23, 2016.
  • Hikaru Akutsu, Kenji Hirata, Akihiro Ohori, Nobuyuki Hattori, and Yoshito Ohta, “ Decentralized control of inverter networks for PV generation plants using real-time pricing strategy “ The Seventh Conference on Innovative Smart Grid Technologies (IEEE ISGT 2016), Minneapolis, September 6-9, 2016,

2015

  • Kenji Kashima, Hiroki Aoyama, and Yoshito Ohta, “ Modeling and linearization of systems under heavy-tailed stochastic noise with application to renewable energy assessment, “ The 54th IEEE Conference on Decision and Control, pp. 1852-1857, Osaka, Japan, December 15-18, 2015.
  • Takaya Ishii, Kenji Hirata, Akihiro Ohori, Nobuyuki Hattori, and Yoshito Ohta, “ Distributed active and reactive-power flow management for grid voltage maintenance using real-time pricing strategy, The 54th IEEE Conference on Decision and Control, pp.1322-1327, Osaka, Japan, December 15-18, 2015.
  • Hideyuki Tanaka, and Yoshito Ohta, “ Grey-box modeling of an inverted pendulum system via identification of a PD-LTI system, “ The 47th ISCIE International Symposium on Stochastic Systems Theory and Its Applications, Honolulu, Hawaii, USA, December 5-8, 2015.
  • Hideyuki Tanaka, and Yoshito Ohta, “ Local structural identifiability for a class of parameter-dependent mechanical systems, “ The 17th IFAC Symposium on System Identification Beijing, China, October 19-21, 2015.
  • Hidenori Shingin, and Yoshito Ohta, “ SNR limitation for amplitude-bounded noise in control over channels with feedback, “ 2015 IEEE Multi-Conference on Systems and Control, Sydney, Australia, September 21-23, 2015.

2014

  • Hidenori Shingin, and Yoshito Ohta, “ SNR minimization for feedback control systems with amplitude-bounded noise, “ 2014 IEEE Multi-conference on Systems and Control, Antibes, France, October 8-10, 2014.

2013

  • Kotaro Hashikura, Akira Kojima, and Yoshito Ohta, “ On construction of an H preview output feedback law, “ SICE Journal of Control, Measurement, and System Integration, vol. 6, no. 3, pp. 167--176, 2013.
  • Yoshito Ohta, Akihiro Ohori, Nobuyuki Hattori, and Kenji Hirata, “ Controller design of a grid-tie inverter bypassing DQ transformation, “ The 52nd IEEE Conference on Decision and Control, pp.2927--2932, Florence, Italy, December 10-13, 2013.
  • Marco Bergamasco, Marco Lovera, and Yoshito Ohta, “ Bootstrap-Based Model Uncertainty Assessment in Continuous-Time Subspace Model Identification, “ The 52nd IEEE Conference on Decision and Control, pp.5840--5845, Florence, Italy, December 10-13, 2013.
  • Hideyuki Tanaka, and Yoshito Ohta, “ Grey-box modeling for mechanical systems in frequency domain, “ The 45th ISCIE International Symposium on Stochastic Systems Theory and Its Applications, Okinawa, Japan, November 1, 2013. (extended abstract review)
  • Kotaro Hashikura, Akira Kojima, and Yoshito Ohta “ Reduced-order construction of H state feedback law for discrete-time single input-delayed system, “ The 1st IFAC Workshop on Control of Systems Governed by Partial Differential Equations (CPDE), Paris, September 25-27, 2013.
  • Hidenori Shingin, and Yoshito Ohta, “ Stabilization under signal-to-noise ratio constraints on feedback links with bounded noise, “ The 4th IFAC Workshop on Distributed Estimation and Control in Networked Systems, Rhine-Moselle-Hall, Koblenz, Germany, September 25-26, 2013.

2012

  • Hidenori Shingin, and Yoshito Ohta, “ Disturbance rejection with information constraints: performance limitations of a scalar system for bounded and Gaussian disturbances ” Automatica, vol.48, no.6, pp.1111-1116, 2012.
  • Kotaro Hashikura, Yoshito Ohta, and Akira Kojima, “ An Internal State Decomposition Approach to a Discrete-time H2 Control Problem with Irrational Input Non-minimum Phase Property ” Systems & Control Letters, vol.61, no.4, pp.513-520, 2012.
  • Xin Tan, Hideyuki Tanaka, and Yoshito Ohta, “ Grey-box Modeling of Rotary Type Pendulum System with Variable Load, “ The 16th IFAC Symposium on System Identification, pp.1263--1268, Brussels, Belgium, July 11-13, 2012.
  • Kotaro Hashikura, Akira Kojima, and Yoshito Ohta, “ On a discrete-time H control problem with additional input non-minimum phase property, “ The 20th Mathematical Theory of Networks and Systems (MTNS-2012), Melbourne, Australia, July 2012.

2011

  • Y. Ohta, “ Stochastic system transformation using generalized orthonormal basis functions with applications to continuous-time system identification ” Automatica, vol.47, no.5, pp.1001--1006, 2011.
  • Hideyuki Tanaka, and Yoshito Ohta “ A local approach to LPV-identification of a Twin Rotor MIMO System, “ The 18th IFAC World Congress, Milan, Italy, pp.9029-9034, 2011.
  • Yoshito Ohta, “ System transformation of unstable systems induced by a shift-invariant subspace, “ The 50th IEEE Conference on Decision and Control and European Control Conference, Orlando, USA, pp.1201-1206, 2011.
  • Marco Bergamasco, Marco Lovera, and Yoshito Ohta, “ Recursive continuous-time subspace identification using Laguerre filters, “ The 50th IEEE Conference on Decision and Control and European Control Conference, Orlando, USA, pp.6469--6474, 2011.

2010

  • Yasuhiro Kinoshita, and Yoshito Ohta, “ Continuous-time system identification using compactly-supported filter kernels generated from Laguerre basis functions ” The 49th IEEE Conference on Decision and Control, Atlanta, pp.4461-4466, 2010.
  • Hideyuki Tanaka, Jaafar ALMutawa, and Yoshito Ohta, “ Spectral density function under observation outliers, “ Mathematical Theory of Networks and Systems (MTNS-2010), Budapest, pp.1365-1370, 2010.
  • Hidenori Shingin, and Yoshito Ohta, “ Reduction of state variables based on regulation and filtering performances, “ Mathematical Theory of Networks and Systems (MTNS-2010), Budapest, pp.1437-1442, 2010.
  • Kotaro Hashikura, and Yoshito Ohta, “ A unified solution of a class of continuous/discrete-time H2 control, “ Mathematical Theory of Networks and Systems (MTNS-2010), Budapest, pp.1707-1712, 2010.
  • Koichi Abiko, Hirata Kenji, and Yoshito Ohta “ Motion switching control of robotic manipulators and reducing a throughput time in handling semiconductor wafers, “ SICE Annual Conference 2010, Taipei, pp.3375-3381, 2010.

2009

  • Hidenori Shingin, and Yoshito Ohta, “ Disturbance rejection with information constraints: performance limitations of a scalar system for bounded and gaussian disturbances, “ The 1st IFAC Workshop on Estimation and Control of Networked Systems (NecSys'09), pp.304-309, Venice, Italy, September 24-26, 2009.
  • Yoshito Ohta, “ An abstract linear programming approach to continuous-time LQ control for constrained systems, “ The 48th IEEE Conference on Decision and Control, Shanghai, China, pp.7949-7954, 2009.

2008

  • K. Hirata and Y. Ohta, “ Exact determinations of the maximal output admissible set for a class of nonlinear systems, ” Automatica, vol.44, no.2, pp.526-533, 2008.

2007

  • Y. Ohta, “ A Study on Stochastic System Transformation Using Generalized Orthonormal Basis Functions, ” The 46th IEEE Conference on Decision and Control, pp.3114-3119, New Orleans, USA, December, 2007.
  • Yoshito Ohta, “ Frequency response of transformed linear systems using generalized orthonormal basis functions “ The 8th International Symposium on Quantitative Feedback Theory and Robust Frequency Domain Methods, The Weizmann Institute of Science, Rehovot, Israel, July 17-19, 2007.
  • T. Chimbe, and Y. Ohta, “ Error analysis of continuous-time system identification using Laguerre basis, “ SICE Annual Conference 2007, Takamatsu, Japan, pp.2550-2555, September 17-20, 2007.

2006

  • H. Shingin and Y. Ohta, “ Disturbance rejection with information constraints, ” Proceedings Seventeenth International Symposium on Mathematical Theory of Networks and Systems (MTNS-2006), Kyoto, Japan, July 24-28, 2006.

2005

  • Y.Ohta, “ Realization of input-output maps using generalized orthonormal basis functions, ” Systems & Control Letters, vol.54, no.6, pp.521-528, 2005.
  • Akarawit Limpiyamitr, and Yoshito Ohta, “ The duality relation between maximal output admissible set and reachable set, “ The 44th IEEE Conference on Decision and Control and European Control Conference ECC '05, pp.8282--8287, Seville, Spain, December 12-15, 2005.
  • Shinsuke Oh-hara, Kenji Hirata and Yoshito Ohta, “ The translatory motion control of wafer transfer robots by switching gain scheduled controllers, “ 2005 CACS Automatic Control Conference, T00015i, Tainan, Taiwan, November 18-19, 2005.

2004

  • Eiji Morinaga, Kenji Hirata, and Yoshito Ohta, “ Performance analysis of control systems with input constraints via piecewise quadratic storage functions, “ Asian Journal of Control, Vol. 6, No. 1, pp.34--45, 2004.
  • Yoshito Ohta, “ Abstract linear programming approach to control problems approximation theory, “ The 43rd IEEE Conference on Decision and Control, The Bahamas, pp. 3145-3146, December 14-17, 2004.
  • Kenji Hirata, and Yoshito Ohta, “ The maximal output admissible set for a class of uncertain systems, “ The 43rd IEEE Conference on Decision and Control, The Bahamas, pp. 2686-2691, December 14-17, 2004.
  • Y.Ohta and T,Kawai, “ Continuous-time subspace system identification using generalized orthonormal basis functions, ” Proceedings Sixteenth International Symposium on Mathematical Theory of Networks and Systems (MTNS-2004), Leuven, ISBN 90-5682-517-8, 2004.
  • A. Limpiyamitr and Y.Ohta, “ On the Approximation of Maximal Output Admissible Set and Reachable Set via Forward Euler Discretization, ” Proceedings of the 10th IFAC/IFORS/IMACS/IFIP Symposium on Large Scale Systems: Theory and Applications, Osaka, pp.407-412, July 26-28, 2004.
  • H. Shingin and Y. Ohta, “ Optimal Invariant Sets for Descrete-Time Systems: Approximation of Reachable Sets for Bounded Inputs, ” Proceedings of the 10th IFAC/IFORS/IMACS/IFIP Symposium on Large Scale Systems: Theory and Applications, Osaka, pp.401-406, July 26-28, 2004.

2003-1984

  • Y.Ohta and T.Kunitake, “ L2 gain analysis of linear parameter varying systems: dual problem and its finite dimensional approximation, ” The 42 nd IEEE Conference on Decision and Control, Maui, USA, pp.306-311, December 9-12, 2003.
  • Kenji Hirata, and Yoshito Ohta, “ ε-feasible approximation of the state reachable set for discrete-time systems, “ The 42nd IEEE Conference on Decision and Control, Maui, USA, pp.5520--5525, December 9-12, 2003.
  • Y.Ohta, and T.Kawai, “ Realization of input-output maps using generalized orthogonal basis functions, “ 2003 American Control Conference, Denver, USA pp.95--100, June 4-6, 2003.
  • Y.Ohta, and T.Kunitake, “ Control system design based on duality theorem, “ The 41 st IEEE Conference on Decision and Control, Las Vegas, USA, pp.2762--2767, December 10-13, 2002.
  • Eiji Morinaga, Kenji Hirata, and Yoshito Ohta, “ Analysis of control systems with input constraints using piecewise quadratic storage functions, “ The 4th Asian Control Conference, pp.1756--1761, 2002.
  • Y.Ohta, “ l1 Controller Design with Frequency Domain Constraints: Finite Dimensional Approximation of Dual Problems, ” The 40 th IEEE Conference on Decision and Control, Las Vegas, USA, pp.1125-1130, December 4-7, 2001.
  • Y.Ohta, “ A study on the norm of mixed Hankel-Toeplitz operator, “ 2000 American Control Conference, Chicago, USA, pp.2765--2769, June 28-30, 2000.
  • Y.Ohta, “ Hankel singular values and vectors of a class of infinite-dimensional systems: exact Hamiltonian formulas for control and approximation problems, ” Mathematics of Control, Signals, and Systems, vol.12, no.4, pp.361-375, 1999.
  • Y.Ohta and A.Kojima, “ Formulas for Hankel singular values and vectors for a class of input delay systems, ” Automatica, vol.35, no.2, pp.201-215, 1999.
  • Yoshito Ohta and Yoshihide Toude, “ Minimization of the maximum peak-to-peak gain with time domain constraints on fixed input response, “ The 38 th IEEE Conference on Decision and Control, Phoenix, USA, pp.1439--1444, December 7-10, 1999.
  • Yoshito Ohta, “ Hankel singular values and vectors of a class of infinite dimensional systems with totally ordered inner functions, “ The 37th IEEE Conference on Decision and Control, Tampa, USA, pp.610--615, December 16-18, 1998.
  • Yoshito Ohta, “ Further results on Hankel singular values and vectors of a class of infinite dimensional systems, “ 1998 American Control Conference, Philadelphia, pp.644--648, June 24-26, 1998.
  • Yoshito Ohta, “ Hankel singular values and vectors of a class of infinite dimensional systems for control and approximation problems, “ The 36th IEEE Conference on Decision and Control, San Diego, USA, pp.2765--2770, December 10-12, 1997.
  • Y.Ohta, and O.Goto, “ Further results on the interpolation point augmentation method: continuous-time L1} control, “ The 35th IEEE Conference on Decision and Control, Kobe, Japan, pp.4026-4027, 1996.
  • Y. Ohta, and I.C.Hwang, “ Hankel approximation of commensurate input delay systems, “ The 35th IEEE Conference on Decision and Control, Kobe, Japan, pp.3167-3172, 1996.
  • Y.Ohta, N.Adachi and H.Kimura, “ Interpolation point augmentation method for multiblock model matching problems : multi-input multi-output L1 optimal control, ” The 33 rd IEEE Conference on Decision and Control, pp.3137-3142, 1994.
  • Y.Ohta, H.Maeda and S.Kodama, “ Rational approximation of L1 optimal controllers for SISO systems, ” IEEE Transactions on Automatic Control, vol.37, no.11, pp.1683-1691, 1992.
  • M.A.Dahleh, and Y.Ohta, “ L1 sensitivity minimization for plants with commensurate delays, “ Mathematics of Control, Signals, and Systems, vol.5, no.3, pp.281-294, 1992.
  • Y.Ohta, H.Maeda and S.Kodama, “ Unit interpolation in H : bounds of norm and degree of interpolants, ” Systems & Control Letters, vol.17, pp.251-256, 1991.
  • M.A.Dahleh and Y.Ohta, “ A necessary and sufficient condition for robust BIBO stability, ” Systems & Control Letters, vol.11, pp.271-275, 1988.
  • Yoshito Ohta, Gilead Tadmor, and Sanjoy.K. Mitter, “ Sensitivity reduction over a frequency band,'' “ International Journal of Control, vol.48, no.5, pp.2129-2138, 1988.
  • M.A.Dahleh and Y.Ohta, “ Robustness in the l1-based design methodology, “ The 27th IEEE Conference on Decision and Control, Austin, USA, pp.2199-2201, 1988.
  • M.A.Dahleh and Y.Ohta, “ L1 sensitivity minimization for plants with commensurate delays, “ The 27th IEEE Conference on Decision and Control, Austin, USA, pp.2171-2175, 1988.
  • Yoshito Ohta, Hajime Maeda, and Shinzo Kodama, “ Factorization of the minors of characteristic matrix sI-A and DM decompositions of its representation graph, “ Journal of the Franklin Institute, vol.324, no.2, pp.245-262, 1987.
  • Hajime Maeda, Yoshito Ohta, and Shinzo Kodama, “ Fault diagnosis of non-linear systems: graphical approach to detectability, distinguishability and diagnosis algorithm, ” Circuit Theory and Applications, vol.14, pp.195--209, 1986.
  • Yoshito Ohta, and Shinzo Kodama, “ Structural invertibility of transfer functions, “ IEEE Transactions on Automatic Control, vol.AC-30, no.8, pp.818--819, 1985.
  • Yoshito Ohta, Hajime Maeda, and Shinzo Kodama, “ Reachability, observability, and realizability of continuous-time positive systems, ” SIAM J. Control and Optimization, vol.22, no.2, pp.171-180, 1984.


|Biography |Research |Courses |

Last Modified: April 11, 2018