• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.479-484
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• 1992

The resolved motion rate control (RMRC) is converting to Joint space trajectory from given Cartesian space trajectory. The RMRC requires the inverse of Jacobian matrix. Since the Jacobian matrix of the redundant robot is generally not square, the pseudo-inverse must be introduced. However the pseudo-inverse is not easy to be implemented on a digital computer in real time as well as mathematically complex. In this paper, a simple fuzzy resolved motion rate control (FRMRC) that can replace the RMRC using pseudo-inverse of Jacobian is proposed. The proposed FRMRC with appropriate fuzzy rules, membership functions and reasoning method can solve the mapping problem between the spaces without complexity. The mapped Joint space trajectory is sufficiently accurate so that it can be directly used to control redundant manipulators. Simulation results verify the efficiency of the proposed idea.

• 제어로봇시스템학회논문지
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• 제5권7호
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• pp.808-813
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• 1999

A fuzzy learning method to control an unstable and multivariable system is presented in this paper, Because the multivariable system has generally a coupling effect between the inputs and outputs, it is difficult to find its modeling equation or parameters. If the system is unstable, initial condition rules are needed to make it stable because learning is nearly impossible. Therefore, this learning method uses the initial rules and introduces a cost function composed of the actual error and error-rate of each output without the modeling equation. To minimize the cost function, we experimentally got the Jacobian matrix in the operating point of the system. From the Jacobian matrix, we can find the direction of the convergence in the learning, and the optimal control rules are finally acquired when the fuzzy rules are updated by changing the portion of the errors and error rates.

• 제어로봇시스템학회논문지
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• 제9권12호
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• pp.1026-1032
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• 2003

A biped walking robot which is developed as a platform for researching walking algorithm is briefly introduced. The developed walking robot has 6 degrees of freedom per one leg. The origins of the last three axis do not intersect at a point, so the kinematic analysis is cubmersome with the conventional method. In the former version of the robot, Jacobian-based inverse kinematics method is used. However, the Jacobian-based inverse kinematics method has drawbacks for the application in which knee is fully extended such as stair-case walking. The reason far that is the Jacobian becomes ill-conditioned near the singular points and the method is not able to give adequate solutions. So, a method for giving a closed-form inverse kinematics solution is proposed. The proposed method is based on careful consideration of the kinematic structure of the biped walking robot.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.529-535
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• 2000

This paper propose the method to obtain the inverse kinematics and the Jacobian of the 5-bar parallel robot and apply the nonlinear controller to the 5-bar parallel robot with the dynamic analyses using the Jacobian of the Passive joints with respect to the active ones and singular value decomposition(SVD). It also experimentally shows that we can do high-speed and accuracy tasks using nonlinear control method. And it explains the relation between the property of the position control and manipulability using a new performance index.

• 대한전기학회논문지:전력기술부문A
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• 제49권7호
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• pp.365-368
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• 2000

Traditionally, load flows have been calculated using the Gauss-Seidel and Newton-Raphson Method. DistFlow Method which is proposed by Wu and Baran is superior to the other two methods because it does not require the admittance matrix calculation to optimize the distribution system. This paper introduces a new alternative algorithm to the DistFlow Method which is slow and complex to find solutions as the number of lateral and sublateral increases. The proposed load flow method can construct System Jacobian easily. We can minimize the off-diagonal elements of the branch Jacobian and submatrices in the System Jacobian. Simulation results show that progressive performances of the proposed algorithm have a better convergence time.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 A
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• pp.248-250
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• 1999

본 논문에서 제안된 조류계산 알고리즘은 Jacobian의 off-diagonal 부 행렬을 완전히 무시하는 Decoupled Load Flow(DCL) 알고리즘들의 유연한 대안으로 반복(iteration)당 최소한의 추가 계산 부담으로 Jacobian의 off-diagonal 부분의 효과를 부분적으로 반영함에 의해 수렴 특성을 향상시킬 수 있다. 제안된 방법들은 특히 Fast Decoupled Load Flow(FDL)로 대표되는 DCL들의 수렴특성이 불안정해질 경우, 효과적으로 수렴특성을 향상시킬 수 있다. 제안된 알고리즘들은 Newton-Raphson Load Flow(NRL) 방법에서 Jacobian의 off-diagonal 부분의 효과를 점진적으로 제거하는 방법으로 유도하였고, 간략화 과정에서는 Neuman series expansion을 사용하였다. 실험결과 제안된 알고리즘들은 반복횟수와 전반적인 수렴 속도에서 확실한 성능향상을 보여주었다. 제안된 알고리즘들은 특히 DCL의 수렴성능이 문제가 있을 시 full NRL 대신에 적용할 수 있는 가능성이 있어 조류계산 시간을 단축해 줄 수 있을 것으로 기대된다.

• 한국정밀공학회지
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• 제20권2호
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• pp.85-93
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• 2003

Generally, it is very difficult to get a modeling equation because multi-variable system has coupling relations between its inputs and outputs. To design an optimal controller without the modeling equation, this paper proposes a neural-network (NN) controller being learned by Jacobian matrix. Another major characteristic is that the controller consists of two separated NN controllers, namely, proportional control part and derivative control part. Simulation results for a catamaran system show that the proposed NN controller is superior to LQR in the regulation and tracking problems.

• 대한전기학회논문지
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• 제43권2호
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• pp.189-196
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• 1994

This paper describes a parallel computing algorithm in Gauss elimination of Jacobian matrix to large-scale power system. The structure of Jacobian matrix becomes different according to ordering method of buses. In sequential computation buses are ordered to minimize the number of fill-in in the triangulation of the Jacobian matrix. The proposed method develops the parallelism in the Gauss elimination by using ND(nested dissection) ordering. In this procedure the level structure of the power system network is transformed to be long and narrow by using end buses which results in balance of computing load among processes and maximization of parallel computation. Each processor uses the sequential computation method to preserve the sqarsity of matrix.

• 전기학회논문지
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• 제64권4호
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• pp.578-585
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• 2015

Electromagnetic levitation system(EMLS) is one of the well known nonlinear systems. Often, it is not easy to control an EMLS due to its high nonlinearity. In this paper, we first apply two linearization method(jacobian and input-output feedback linearization) to design two feedback controllers for an EMLS. Then, by observing the advantages of each controller, we design a switching control algorithm which engage two controllers depending on the position of the steel ball in order to achieve the improved performance over each controller. The validity of our switching control approach is verified via both simulation and actual experimental results.

• Journal of Electrical Engineering and Technology
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• 제8권2호
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• pp.385-392
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• 2013

An uncalibrated visual servo control method for tracking a target is presented. We define the robot-positioning problem as an unconstrained optimization problem to minimize the image error between the target feature and the robot end-effector feature. We propose a method to find the residual term for more precise modeling using the secant approximation method. The composite image Jacobian is estimated by the proper method for eye-to-hand configuration without knowledge of the kinematic structure, imaging geometry and intrinsic parameter of camera. This method is independent of the motion of a target feature. The algorithm for regulation of the joint velocity for safety and stability is presented using the cost function. Adaptive regulation for visibility constraints is proposed using the adaptive parameter.