• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
• /
• pp.245-248
• /
• 1997

The control modes used in teleoperation are position control mode, and rate control mode. This paper presents the problems of the conventional control modes, through simulation, proposes an intelligent mixed control mode that converts the operation mode between the position mode and the rate mode intelligently by judging the operator's intention using the real-time measurement data. The effectiveness of the proposed intelligent mixed control mode is demonstrated and compared to other typical control modes through simulation and actual experiment.

• 대한수학회보
• /
• 제50권1호
• /
• pp.321-341
• /
• 2013

In this paper, we discuss the a posteriori error estimates of the semidiscrete mixed finite element methods for quadratic optimal control problems governed by linear hyperbolic equations. The state and the co-state are discretized by the order $k$ Raviart-Thomas mixed finite element spaces and the control is approximated by piecewise polynomials of order $k(k{\geq}0)$. Using mixed elliptic reconstruction method, a posterior $L^{\infty}(L^2)$-error estimates for both the state and the control approximation are derived. Such estimates, which are apparently not available in the literature, are an important step towards developing reliable adaptive mixed finite element approximation schemes for the control problem.

• International Journal of Control, Automation, and Systems
• /
• 제1권2호
• /
• pp.206-209
• /
• 2003

An $H_2$/$H_{\infty}$ -controller realization is carried out by considering an entropy integral. Using J-spectral factorization, the parametrizations of all $H_{\infty}$ stabilizing controllers are derived. By the relation of a mixed $H_2$/$H_{\infty}$ control problem and a minimum entropy/$H_{\infty}$ control problem, the mixed $H_2$/$H_{\infty}$-controller state-space realization is presented.

• International Journal of Control, Automation, and Systems
• /
• 제6권1호
• /
• pp.1-14
• /
• 2008

This paper presents a convex optimization method for observer-based mixed $H_2/H_{\infty}$ control design of linear systems with time-varying state, input and output delays. Delay-dependent sufficient conditions for the design of a desired observer-based control are given in terms of linear matrix inequalities (LMIs). An observer-based controller which guarantees asymptotic stability and a mixed $H_2/H_{\infty}$ performance for the closed-loop system of the linear system with time-varying delays is then developed. A Lyapunov-Krasovskii method underlies the observer-based mixed $H_2/H_{\infty}$ control design. A numerical example with simulation results illustrates the effectiveness of the methodology.

• 한국식품영양학회지
• /
• 제28권2호
• /
• pp.196-201
• /
• 2015

쌀밥 위주의 식사에서 곡류 또는 두류를 혼합한 잡곡밥의 섭취량이 늘고 있는 추세로 백미(대조군)와 혼합잡곡(혼합잡곡 1), 혼합잡곡에 정미성분을 가미한 잡곡(혼합잡곡 2)을 제조하고, 이들의 항산화 활성을 갖는 성분들의 함량 변화와 기호도 변화를 측정하였다. Ascorbic acid의 함량에서는 백미의 경우, 6.68 mg%, 혼합잡곡군은 각각 18.23 및 21.84 mg%로 잡곡을 혼합하였을 때 높은 함량을 나타내었다. Tocopherol류의 함량에서는 백미는 1.26 mg%, 혼합잡곡 1군은 19.24 mg%이었고, 혼합잡곡에 정미성분을 가미한 혼합잡곡 2군은 39.32 mg%로 가장 높은 tocopherol류의 함량을 보였다. Polyphenol 화합물의 함량에서 대조군은 2.20 mg%, 혼합잡곡군은 각각 14.38 및 21.91 mg%로 혼합잡곡군이 높은 함량을 보였다. Flavonoid 화합물의 함량은 대조군에서는 검출되지 않았지만, 혼합잡곡 1군은 42.45 mg%, 혼합잡곡 2군은 32.54 mg%로 잡곡 혼합 시 높은 함량을 나타내었으며, 이들 성분들은 메탄올 추출물에서도 유사한 경향이었다. 기호도에서는 맛, 향, 색 및 종합적 기호도에서는 모두 정미성분을 첨가하였던 혼합잡곡 2군이 가장 높은 기호도를 보였고, 잡곡밥, 백미의 순으로 백미보다는 곡류 및 두류 및 정미성분을 혼합하는 것을 더욱 선호하였다.

• 대한수학회보
• /
• 제50권4호
• /
• pp.1127-1144
• /
• 2013

In this paper, we consider the error estimates of the numerical solutions of a class of fourth order linear-quadratic elliptic optimal control problems by using mixed finite element methods. The state and co-state are approximated by the order $k$ Raviart-Thomas mixed finite element spaces and the control variable is approximated by piecewise polynomials of order $k(k{\geq}1)$. $L^2$ and $L^{\infty}$-error estimates are derived for both the control and the state approximations. These results are seemed to be new in the literature of the mixed finite element methods for fourth order elliptic control problems.

• 전기학회논문지
• /
• 제59권10호
• /
• pp.1908-1913
• /
• 2010

In this paper, a robust variable structure tracking controller is designed for the mixed tracking control of highly nonlinear rigid robot manipulators for the first time. The mixed control problem under consideration is extended from the basic tracking problem, with the different initial condition of both the planned trajectory and link of robots. This control problem in robotics is not addressed to until now. The tracking accuracy to the sliding trajectory after reaching is analyzed. The stability of the closed loop system is investigated in detail in Theorem 2. The results of Theorem 2 provide the stable condition for control gains. Combing the results of Theorem 1 and Theorem 2 gives rise to possibility of designing the improved variable structure tracking controller to guarantee the tracking error from the determined sliding trajectory within the prescribed accuracy after reaching. The usefulness of the algorithm has been demonstrated through simulation studies on the mixed tracking control of a two.link robot under parameter uncertainties and payload variations.

• Journal of applied mathematics & informatics
• /
• 제26권5_6호
• /
• pp.819-837
• /
• 2008

A mixed type dual to the control problem in order to unify Wolfe and Mond-Weir type dual control problem is presented in various duality results are validated and the generalized invexity assumptions. It is pointed out that our results can be extended to the control problems with free boundary conditions. The duality results for nonlinear programming problems already existing in the literature are deduced as special cases of our results.

• Journal of Electrical Engineering and information Science
• /
• 제1권1호
• /
• pp.29-38
• /
• 1996

To improve the reliability of control systems, certain robustness to plant uncertainties and disturbance inputs is required in terms of well founded mathematical basis. Robust control theory was set up and developed until now from this motivation. In this field, H$_2$or H\ulcorner norm performance measures are frequently used nowadays. Moreover a mixed H$_2$/H\ulcorner control problem is introduced to combine the merits of each measure since H$_2$control usually makes more sense for performance while H\ulcorner control is better for robustness to plant perturbations. However only some partial analytic solutions are developed to this problem under certain special cases at this time. In this paper, the mixed H$_2$/H\ulcorner control problem is considered. The analytic(or semi-analytic) solutions of (sub)optimal mixed H$_2$/H\ulcorner state-feedback controller are derived for the scalar plant case and the multivariable plant case, respectively. An illustrative example is given to compare the proposed analytic solution with the existing numerical one.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2003년도 ICCAS
• /
• pp.438-443
• /
• 2003

In this paper, we propose a control algorithm for two-wheel mobile robot that can move the rider to his or her command and autonomously keep its balance. The control algorithm is based on a mixed $H_2/H_{\infty}$ control scheme. In this control problem the main issue is to move the rider while keeping its balance in the presence of disturbances and parameter uncertainties. The disturbance force caused by uneven road surfaces and the uncertainty due to different rider's heights are considered. To this end we first consider a state feedback controller as a basic framework. Secondly, we obtain the state feedback gain $K_2$ minimizing the $H_2$ norm and the state feedback gain $K_{\infty}$ minimizing the $H_{\infty}$ norm over the whole range of parameter uncertainty. Finally, we select mixed $H_2$/$H_{\infty}$ state feedback controller K as the geometric mean of $K_2$ and $K_{\infty}$. Simulation results show that the mixed $H_2/H_{\infty}$ state feedback controller combines the effects of the optimal $H_2$ state feedback controller and robust $H_{\infty}$ controller state feedback controller efficiently in the presence of disturbance and parameter uncertainty.