• Journal of the Korea Institute of Military Science and Technology
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• v.3 no.1
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• pp.138-145
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• 2000

This paper presents a robust fault diagnosis and fault tolerant control method for the control systems in closed-loop affected by unknown inputs or disturbances. The fault diagnostic scheme is based on the disturbance-decoupled state estimation using a 2-stage state observer for state, actuator bias and sensor bias. The estimated bias show the occurrence time, location and type of the faults directly. The estimated state is used for state feedback to achieve fault tolerant control against the faults. Simulation results show that the method has definite fault tolerant ability against actuator and sensor faults, moreover, the faults can be detected on-line, isolated and estimated simultaneously.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.92-92
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• 2000

Helicopter offer the signigicant advantage over traditional air vehicles, in that the provide extended maneuverability, such as vertical climb, hovering, longitudinal and lateral flight, hovering turns and bank turns. But helicopter have the strong cross couplings and nonlinearities for each lateral, longitudinal and rotational motion mutually. However, it is possible to ignore this couplings for the hovering condition, so using this properties we can control the attitude of helicopter. That is, by implementing the dynamic of each rotational axis(roll, pitch, yaw) of independent mutually, 3-DOF(degree of Freedom) attitude control for the helicopter is possible. In this paper, we identify decoupled input-coutput relations of each three rotational axis about the helicopter mounted on the 3-DOF gimbal by experiment, and on these basis implement 3-DOF attitude controller using the PID control method.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.130-130
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• 2000

This paper presents a robust fault diagnosis and fault tolerant control lot the actuator and sensor faults in the closed-loop systems affected by unknown inputs or disturbances. The fault diagnostic scheme is based on the residual set generation by using robust Parity space approach. Residual set is evaluated through the threshold test and then fault is isolated according to the decision logic table. Once the fault diagnosis module indicates which actuator or sensor is faulty, the fault magnitude is estimated by using the disturbance-decoupled optimal state estimation and a new additive control law is added to the nominal one to override the fault effect on the system. Simulation results show that the method has definite fault diagnosis and fault tolerant control ability against actuator and sensor faults.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.921-925
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• 1988

An attractive approach to speed of induction motors is to achieve full linearization via appropriate feedback. However, the prior results toward this direction are based on full feedback. In practice, rotor fluxes are not directly measurable but can be estimated using observers. We propose a nonlinear feedback controller with an observer. As t${\rightarrow}{\infty}$, the closed-loop system with our controller becomes as if it were a linearly decoupled system. We provide the stability analysis of our control method. Simulation and experimental results are also included to demonstrate the practical significance of our results.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.11
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• pp.877-887
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• 1989

In this paper, we attempt to achieve high dynamic performance by means of decoupled control of rotor speed and flux. Recently developed nonlinear feedback control theories are utilized. The rotor fluxes are estimated based on the rotor circuit equations. When the estimation error of the rotor flux tends to zero, the rotor speed and flux dynamic characteristics of the induction motor with our controller become linear. To minimize the deterioration of control performance, we use an identification algorithm for the rotor resistance. We analyze the dynamic behavior of the closed loop system with our controller. Both simulation and experimental results are included to demonstrate the practical significance of our result. In particular, our experimental results show that recently developed nonlinear feedback control techniques are of practical use in control of induction motors.

• International Journal of Control, Automation, and Systems
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• v.2 no.1
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• pp.92-99
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• 2004

In this paper, the decoupled neural network reference compensation technique (DRCT) is applied to the control of a two degrees-of-freedom inverted pendulum mounted on an x-y table. Neural networks are used as auxiliary controllers for both the x axis and y axis of the PD controlled inverted pendulum. The DRCT method known to compensate for uncertainties at the trajectory level is used to control both the angle of a pendulum and the position of a cart simultaneously. Implementation of an on-line neural network learning algorithm has been implemented on the DSP board of the dSpace DSP system. Experimental studies have shown successful balancing of a pendulum on an x-y plane and good position control under external disturbances as well.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.9
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• pp.768-773
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• 2013

In this paper, decoupled course, depth and roll controller design for an Autonomous Underwater Vehicle (AUV) and its performance test results are presented. Control system design is done using the PD control scheme based on a mathematical model of the AUV. Details of system implementation are given and the results of simulations and experiments using the prototype vehicle model are discussed. The designed controller was successfully applied to the nonlinear and coupled system under non-ideal actuator conditions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.205-209
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• 2006

A linear motor based transfer vehicle is significantly focused as transportation systems in marine terminals for the future. We propose a control method for the systems to hence mass reduction and propulsion effects at a starting point by using a lift-force mechanism. This method is newly based on a combined levitation-and-propulsion power by a lift and thrust force of a permanent magnet linear synchronous motor (PMLSM), which is carried out by a decoupled control. We exam that our proposed control largely compensates the vehicle weight, reduces friction effect of the system, and increases its velocity. Consequently, this result contributes numerous productivity and economical efficiency for the port systems.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.899-907
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• 2014

This paper deals with fault-tolerant control of five-phase induction motor (IM) drives under single-phase open. By exploiting a decoupled model for five-phase IM under fault, the indirect field-oriented control ensures that electromagnetic torque oscillations are reduced by particular magnitude ratio currents. The control techniques are developed by the third harmonic current injection, in order to improve electromagnetic torque density. Furthermore, Proportional Resonant (PR) regulator is adopted to realize excellent current tracking performance in the phase frame, compared with Proportional Integral (PI) and hysteresis regulators. The analysis and experimental results confirm the validity of fault-tolerant control under single-phase open.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.123-128
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• 1996

Kinematically redundant manipulators have been studied because of its usefulness of kinematic redundancy. It is natural that the kinematic redundancy induces a kind of control redundancy. By using the weighted kinematically decoupled joint space decomposition, we unify the control redundancy and the kinematic redundancy parameterized by the joint space weighting matrix. Concentrating to the particular component of each decomposition, we can describe the local minimization behavior of the control weighted quadratic by each weighted decomposition. The result extends the conventional results on general setting, and should be of interest in understanding the motion behavior of kinematically redundant manipulators.