• Ocean Systems Engineering
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• 제8권2호
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• pp.201-221
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• 2018

In this paper a comprehensive study for the structural control of Jacket platform with Magneto-Rheological (MR) damper is presented. The control is implemented as a closed loop feedback of the applied voltage in the MR Damper using fuzzy logic. Nine cases of combinations with MR damper are presented to complete the work. The selection of the MR damper (RD 1005-3) is based on the operating parameters (i.e., the range of frequency and displacement). Bingham model is used to obtain the control forces. The damping co-efficient of the model is obtained using empirical relationship between the voltage in the MR damper and input velocity from the structural members. The force acting on the structure is obtained from Morison equation using P-M spectrum. The results show that the reliable control was obtained when there was a continuous connection of multiple MR dampers with the lower levels of the structure. Independent MR dampers at different levels provided control within a range, while the MR dampers placed at alternate positions gave very high control.

• 전기학회논문지
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• 제59권12호
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• pp.2292-2297
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• 2010

To improve the performances of Sawyer motors and to regulate yaw rotation, various feedback control methods have been developed. Almost all of these methods require information on the position, velocity or full state of the motor. Therefore, in this paper, a nonlinear observer is designed to estimate the full state of the four forcers in a Sawyer motor. The proposed method estimates the full state using only positional feedback. Generally, Sawyer motors are operated within a yaw magnitude of several degrees; outside of this range, Sawyer motors step out. Therefore, this observer design assumes that the yaw is within ${\pm}90^\b{o}$. The convergence of the estimation error is proven using the Lyapunov method. The proposed observer guarantees that the estimation error globally exponentially converges to zero for all arbitrary initial conditions. Furthermore, since the proposed observer does not require any transformation, it may result in a reduction in the commutation delay. The simulation results show the performance of the proposed observer.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
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• pp.133-135
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• 2006

This paper considers a speed control problem of DC motor under load variations. In order to reduce the effect of load variation, a disturbance observer has been designed for the given system. With a cheap encoder there exists considerable measurement noise in the velocity feedback and it should be reflected in designing the disturbance observer. The authors have obtained the nominal transfer function of a DC motor and designed a disturbance observer for the control purpose. With the disturbance observer a digital controller has been implemented using a DSP(TMS320F2812). Some experiments show the enhanced performance of the control system with the proposed method.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.950-957
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• 2003

This paper deals with adaptive fuzzy logic controller design to achieve proper dynamic response of a composite thin-walled beam with a tip mass. In order to check the effectiveness of this controller, three different types of control logic are selected and applied. The adaptive control capabilities provided by a system of piezoactuators bonded or embedded into the structure are also implemented in the system. Results show that the fuzzy logic controller is more effective than the proportional or velocity feedback controller for the vibration control of composit thin-walled beam with a tip mass.

• Transactions on Control, Automation and Systems Engineering
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• 제2권1호
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• pp.1-6
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• 2000

This paper presents a control of active suspension for quarter car model with two degree of freedom by using H$\infty$ method. Absolute velocity of car body is measured for feedback. The system parameter variations are treated with multiplicative uncertainty model. Simulation results show that the H$\infty$ control provides good trade-off between ride quality, suspension packaging and road holding constraints. The experiment with a front wheel suspension system was done to verify the simulation results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.273-277
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• 1988

This paper is to show design of robot manipulator which has 3-link using DC Motor and realization of control algorithm with IBM - XT Micro-computer connected. Gentral algorithm is applicated by position and pass control using point-to-point method. At first, this paper computes required angles on each joint in order to search desired position or path, and uses a voltage control with feedback from output of encoder and tachometer in real time. The application of control algorithm on position, velocity and force for each joint of manipulator by using self-tuning control is left for next study.

• 한국정밀공학회지
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• 제8권3호
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• pp.64-72
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• 1991

This paper deals with the state estimator and controller. All state variables' feedback in the system were used to improve electro hydraulic servo sysem were used to improve electro hydraulic servo system's responese charact- eristics. Many gains of the state variables'and estimator's are produced by the algebraic Riccati equation, and every state variables'optimal gain and estimator gain is selected by trial and error method. For the designed estimator performance's examination, this paper simulate the time response for the step input, the reduced velocity output in subjected to load torque, and the time response for the step input in changing the inertiamoment.

• International Journal of Precision Engineering and Manufacturing
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• 제9권3호
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• pp.40-45
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• 2008

This paper presents a linear positioning system and its control algorithm design with nano accuracy/resolution. The basic linear stage structure is driven by an ultrasonic motor and its displacement feedback is detected by a LDGI (Laser Diffraction Grating Interferometer), which can achieve nanometer resolution. Due to the friction driving property of the ultrasonic motor, the driving situation differs in various ranges along the travel. Experiments have been carried out in order to observe and realize the phenomena of the three main driving modes: AC mode (for mm motion), Gate mode (for ${\mu}m$ motion), and DC mode (for nm motion). A proposed FCMAC (Fuzzy Cerebella Model Articulation Controller) control algorithm is implemented for manipulating and predicting the velocity variation during the motion of each mode respectively. The PCbased integral positioning system is built up with a NI DAQ Device by a BCB (Borland $C^{++}$ Builder) program to accomplish the purpose of an intelligent nanopositioning control.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 추계학술대회 논문집
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• pp.71-76
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• 2010

This paper presents the feasibility for improving the ride quality of railway vehicle equipped with semi-active suspension system using magnetorheological(MR) fluid damper. In order to achieve this goal, a fifteen degree of freedom of railway vehicle model, which includes a car body, bogie frame and wheel-set is proposed to represent lateral, yaw and roll motions. The MR damper system is incorporated with the governing equation of motion of the railway vehicle which includes secondary suspension. To illustrate the effectiveness of the controlled MR dampers on railway vehicle secondary suspension system, the sky-hook control law using the velocity feedback is adopted. Computer simulation for performance evaluation is performed using Matlab. Various control performances are demonstrated under external excitation which is the creep force between wheel and rail.

• 한국전자통신학회논문지
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• 제13권1호
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• pp.93-100
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• 2018

본 연구는 정밀한 각속도 추종을 위해 토크오차를 보상하는 제어기와 구현에서 제어기의 안정성을 보완하는 방법을 제안한다. 또한 설계된 제어기가 점근적인 안정할 수 있음을 리아프노프 안정도이론에 근거하여 증명하였다. 제안된 제어기는 d축 기준전류를 임의 값에 대한 제어가 가능하고, 속도이득과 전류이득의 두 가지로 손쉽게 제어성능을 달성할 수 있도록 하였다. 약 750W급의 IPMSM에 적용한 결과 레퍼런스 속도 1200[RPM]에 대한 정상상태 오차는 0.1[%]이내이며, 약 5[Nm]의 상수부하에서 약 0.2초 이내에 외란을 극복하여 점근적인 안정한 제어기임을 확인 할 수 있다.