• International Journal of Aeronautical and Space Sciences
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• 제18권2호
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• pp.300-314
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• 2017

This paper examines finite rotation angle (FRA) applications for spacecraft attitude control. The coordinate transformation matrix and the attitude kinematics represented by FRAs are introduced. The interpolation techniques for the angular orientations are thoroughly investigated using the FRAs and the results are compared to those using traditional methods. The paper proposes trajectory description techniques by using extremely smooth polynomial functions of time, which can describe point-to-point attitude maneuvers in a realizable and accurate manner with the help of unique FRA features. In addition, new controller design techniques using the FRAs are developed by combining the proposed interpolation techniques with a model predictive control framework. The proposed techniques are validated through their attitude control applications for an aggressive point-to-point maneuver. Conclusively, the FRAs provide much more flexibility than quaternions and Euler angles when describing kinematics, generating trajectories, and designing attitude controllers for spacecraft.

• Journal of Power Electronics
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• 제9권3호
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• pp.456-463
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• 2009

The paper presents a method for controlling induction motors using a nonlinear internal model control (IMC) approach. The process model and the inverse model are developed in the rotor flux coordinate. The main advantage of the proposed method is that it easily specifies the performance (steady state error, transient response, etc.) and the robustness of the controller by means of the IMC filters. Simulation results illustrate the effectiveness of the proposed method. Results on a real time system show that the control system has good performance and robustness against changes in motor parameters (rotor and stator resistances, rotor and stator inductances, rotor inertia).

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.156-160
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• 1993

This paper presents a controller design to coordinate a robot manipulator under unknown system parameters and bounded disturbance inputs. To control the motion of the manipulator, an inverse dynamics control scheme is applied. Since parameters of the robot manipulators such as mass and inertia are not perfectly known, the difference between the actual and estimated parameters works as a disturbance force. To identify the unknown parameters, an inproved adaptive control algorithm is directly derived from a chosen Lyapunov's function candidate based on the Lyapunov's Second Method. A robust control algorithm is devised to counteract the bounded disturbance inputs such as contact forces and disturbing force coming from the difference between th actual and the estimated system parameters. Numerical examples are shown using three degree-of-freedom planar arm.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.552-555
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• 1996

In this paper, we present a force control of a five-axes robot, using an impedance model. Tasks such as assembly, grinding, and deburring, which involve extensive contact with the environment, are better handled by controlling the forces of interaction between the manipulator and the environment. The five-link articulated robot is equipped with a wrist force sensor which consists of an array of strain gauges and can delineate the three components of the vector force along the three axes of the sensor coordinate frame, and the three components of the torque about these axes. For the precise control of the contact force, impedance models of a robot and the environment are defined. Experimental results are shown.

• International Journal of Control, Automation, and Systems
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• 제3권spc2호
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• pp.334-340
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• 2005

Based on the stability margin provided by the EEAC, the unstable contingencies can be classified into sets according to their unstable modes. This two-part paper develops a globally optimal algorithm for transient stability control to coordinate preventive actions and emergency actions. In the first part, an algorithm is proposed for a set of contingencies having identical unstable modes. Instead of iterations between discrete emergency actions and continuous preventive actions, the algorithm straightforwardly searches for a globally optimal solution. The procedure includes assessing a set of insufficient emergency schemes identified by the EEAC; calculating the related preventive actions needed for stabilizing the system; and selecting the scheme with the minimum overall costs. Simulations on a Chinese power system highlight its excellent performance. The positive results obtained are explained by analogizing settlements for 0-1 knapsack problems using the multi-points greedy algorithm.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.1371-1376
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• 1990

The paper presents a method of constructing simple fuzzy control rules for the determination of stabilizing signals of automatic voltage regulator and governor, which are controllers of electric power systems. Fuzzy control rules are simplified by considering a coordinate transformation with the rotation angle .theta. on the phase plane, and by expanding the range of membership functions. Also, two rotation angles .theta. $_{1}$ and .theta. $_{2}$ are selected for the linearizable region and the nonlinear one of the system, respectively. Here, .theta. $_{1}$ is chosen by the pole assignment method, and .theta. $_{2}$ by a performance index. Fuzzy inference is applied to the connection of two rotation angles .theta. $_{1}$ and .theta. $_{1}$ by regarding the distance from the desired equilibrium point as a variable of condition parts. The control effect is demonstrated by an application of the proposed method to one-machine infinite-bus power system.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권10호
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• pp.563-571
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• 2000

In this paper, a nonlinear adaptive control method for an EMS(Electro-Magnetic Suspension) system with mass uncertainty is proposed. Using the coordinate transformation and feedback linearizing control, EMS system has been transformed into the form of parametric strict-feedback system with unknown virtual control coefficients. With this transformed system, tuning functions approach, which is an advanced from of adaptive backstepping, has been applied in order to stabilize the system against mass uncertainty. Computer simulation is also carried out in order to compare the performance of the proposed controller with that of feedback linerizing controller.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.421-424
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• 1987

Recently, the problem associated with the achievement of desired trajectories for non-linear robotic manipulatory systems are researched. The control system which is designed for this robot manipulator, poses a number of severe problem. The methods proposed to deal with the problem fall loosely into three main classes : "direct" "adaptive", "anthropomorphic". Besides there is an approach which is described based upon the application of optimal control theory. In this paper, using the optimal theory, we choose error-coordinate, between the desired trajectories and the practical as the state values, and determine the control law U which minimize a corresponding performance criterion. Let's consider the robotic arm proposed by Freund and set up the deviations of it's trajectory as a measure of performance. To find the optimal control law $U^*$ and the next state value which need to obtain $U^*$ here, we should introduced the conjugate gradient algorithm and the Runge Kutta method.

• 전자공학회논문지B
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• 제33B권7호
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• pp.40-50
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• 1996

An unified compliant control algorithm to regulate the force by dual arms is proposed, where tow arms are treated as one arm in a kinematic viewpoint. The force error calculated form the information of two force/torque sensors attached to the end of each arm is transferred to minimum actuator coordinates, and then is distributed to total system actuator coordinates. The position adjustment at the total actuator coordinates is computed based on the effective computed based on the effective compliance matrix with respect to total actuator coordinates, which is obtained by coordinate transformation between the task coordinates and the total actuator coordinates. An experiment is carried out for dual arms with asymmetric kinematic structure to control an interaction force between manipulators and the environment. The performances of the proposed control algorithm are experimentally compared to those of dual arms employing master/slave scheme. The proposed compliant control algorithm not only ouperforms other algorithms, but also can be treated as an unified approach n the sense that it can be applied to arbitrary dual arm systems with general kinematic structures.

• 한국전자통신학회논문지
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• 제5권5호
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• pp.493-497
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• 2010

선박의 실시간 좌표변환 구현하였고, DC Servo Motor의 Motion Control 알고리즘을 개발하였다. Servo Control 회로설계 및 PCB를 제작하였고, 이를 3-axis Gyro Sensor based Servo Motion Control 제어장치에 적용하여 시스템을 개발하였다. 또한 선박운동을 시뮬레이터하기 위해서 6자유도를 가진 선박용 시뮬레이터를 개발하였다. 개발된 시뮬레이터에 장착된 카메라를 이용하여 선박운동을 추척하는 시험을 한 결과 원하는 오차내에서 추적결과를 보여주었다.