• 제어로봇시스템학회논문지
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• 제22권5호
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• pp.339-345
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• 2016

This paper presents a robust speed control of an autonomous vehicle using a disturbance observer. For the purpose, the transfer function of speed dynamics of an autonomous vehicle is identified using step response data. Based on the identified transfer function, model based PID (Proportional-Integral-Derivative) control is designed. In order to design a robust control against load variations on the vehicle, a disturbance observer (DOB) based control is devised. The performance of the designed DOB based control is demonstrated by real experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1114-1115
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• 2007

In this paper, a new speed sensorless control based on a fuzzy compensator are proposed for the interior permanent magnet synchronous motor (IPMSM) drives. The conventional proportional plus integrate(PI) control are very sensitive to step change of the command speed, parameter variations and load disturbance. To cope with these problems of the PI control, the estimated speeds are compensated by using the fuzzy logic controller (FLC). In the FLC used by the speed compensator of the IPMSM, the system control parameters are adjusted by the fuzzy rule based system, which is a logical model of the human behavior for process control. The effectiveness of algorithm is confirmed by the experiments.

• 대한물리의학회지
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• 제9권3호
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• pp.285-291
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• 2014

PURPOSE: The purpose of this study was to propose clinical criteria to differentiate patients who are able to perform the step-through-step gait pattern in chronic stroke patients. METHODS: Sixty patients with chronic stroke patients participated this study. To differentiate patients who could perform the step-through-step gait pattern, age, gender, and causes of stroke were noted, a Chedoke-McMaster (CM) damage list, Fugl-Meyer (FM) assessment scales and the Berg Balance Scale (BBS) were determined. A 10 meter gait test and Timed Up and Go (TUG) test were conducted to determine the differences in gait speed and dynamic balance between patients walking with or without canes in the step-through-step gait pattern group. RESULTS: There was no significant statistical difference in age, gender, and stroke type between all subjects. There were significant differences in the CM scale for postural and lower extremities, and FM scale for lower extremities and BBS. The dynamic balance ability and gait speed showed significant differences between the subjects in the step-through-step gait pattern with or without a cane during gait. CONCLUSION: CM and FM scales for the lower extremities and postural control, as well as BBS scales, can be used as criteria to differentiate patients who are able to perform the step-through-step gait pattern. These results can also be used to provide beneficial information to patients that are walking with canes.

• 한국자동차공학회논문집
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• 제5권5호
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• pp.37-50
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• 1997

The objective of this paper is to study on the idle speed control using the fuzzy logic controller under load disturbance. The design procedure for fuzzy logic controller depends on the expert's knowledge or trial and error. The inputs of the fuzzy controller are error of rpm and variation of rpm. The output of the fuzzy controller is an ISC motor step and ignition timing. The airflow is controlled by the ISC motor movement and the idle speed is controlled by the airflow control and ignition timing control. During the control, air to fuel was checked by LAMBDA sensor. All experiments were performed in a real vehicle.

• 설비공학논문집
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• 제13권8호
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• pp.780-786
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• 2001

For the compressor speed control of a multi-type air conditioning system, a fuzzy control algorithm was developed. The sum of zone temperature errors and its derivative were used as input variables, and the compressor speed was selected as the output variable. To test the effectiveness of the control algorithm, one outdoor environmental chamber and four indoor environmental chambers were used. In the chambers the zone temperature step change test and the indoor unit change over test were performed. Test results showed that, for the control of compressor speed, the fuzzy control algorithm was more effective than the conventional proportional control algorithm for the energy conservation.

• Journal of Communications and Networks
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• 제12권6호
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• pp.600-604
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• 2010

A method of width adaptation in the radial basis function network (RBFN) using stochastic gradient (SG) algorithm is introduced. Using Taylor's expansion of error signal and differentiating the error with respect to the step-size, the optimal time-varying step-size of the width in RBFN is derived. The proposed approach to adjusting widths in RBFN achieves superior learning speed and the steady-state mean square error (MSE) performance in nonlinear channel environment. The proposed method has shown enhanced steady-state MSE performance by more than 3 dB in both nonlinear channel environments. The results confirm that controlling over step-size of the width in RBFN by the proposed algorithm can be an effective approach to enhancement of convergence speed and the steady-state value of MSE.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.261-264
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• 1997

In case of high speed and high mobility multibody tracked vehicle, it is hard to develop the realtime simulation model for track tension control because of the hundreds of highly nonlinear equations. In order to design more trustworthy realtime simulator for track tension control, it is necessary to use off-line tracked vehicle model. In this study, a step by step procedure is presented to develop realtime simulation model based on off-line tracked vehicle model. Simulation results show that modified off-line multibody tracked vehicle model can be used for real time simulation to control the track tension.

• 전력전자학회논문지
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• 제17권3호
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• pp.205-212
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• 2012

This paper proposes the fuzzy logic based variable step-size MPPT (Maximum Power Point Tracking) method for the stability at the steady state and the improvement of the transient response in the wind power system. If the change value of duty ratio is set on stability of the steady state, MPPT control traces to maximum power point slowly. And if the change value is set on improvement of the transient response, the system output oscillates at the maximum power point. By adjusting the step size with fuzzy logic, it can be improved the MPPT response speed and stability at steady state when MPPT control is performed to track the maximum power point. The effectiveness of the proposed method has been verified by simulations and experimental results.

• Journal of Advanced Marine Engineering and Technology
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• 제16권4호
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• pp.50-59
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• 1992

The paper presents a digital speed control approach of induction motor systems by using a digital servo control method and a well-known second order differential equation as model. The basic concept of using the modeling equation stated in the above is induced from the control theory stand point such that we can describe usually the motor system connected by inverter, generator and load etc, just as a mechanical system to be controlled. The concept does not demand us the complicated vector-based modeling equation adopted in the traditional methods for the speed control of induction motor. Futhermore, the proposed speed control system can be treated as a single input and single output system. The effectiveness of the servo control system obtained by the above-mentioned design concept is illustrated by the experimental results in the presence of both step reference changes and load variations. It is observed from the experimental results that the steady state-error of the experimental set up becomes zero after some regulation time and the induction motor system is robust in spite of reference signal changes and load variations.

• 전자공학회논문지SC
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• 제40권3호
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• pp.127-134
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• 2003

본 논문에서는 퍼지제어를 이용하여 사람의 얼굴을 추적하는 카메라를 구동하는 시스템을 구현한다. 팬틸트(Pan Tilt)구조를 가진 카메라 시스템은 먼저 영상을 PC로 보내고 PC에서는 추적알고리즘에 의한 추적 좌표를 다시 카메라에 전송하면 카메라는 목표 얼굴을 실시간으로 추적하는 방식으로 되어 있다. 카메라를 구동하는 2축의 스텝모터는 PC에서 전송된 목표 좌표로 최대한 빠르고 또한 부드럽게 제어되어야 한다. 이를 위해서 본 논문에서는 퍼지제어기를 제안하여 구동용 가·감속 주파수를 만들고 두 축의 스텝모터를 빠르면서도 부드럽게 제어한다 그리고 본 제안 방식의 효율성을 검증하기 위하여 실험 장치를 제작하고 실험을 수행한다.