• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.728-733
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• 2003

In human-mechanical cooperative systems, a significant issue is to improve the control performance and the maneuvering feeling of human operation. However, since it is not easy to evaluate the feeling of operators numerically, control engineers design controllers only through experience. Thus, in this paper, a new evaluation method for control performance of human-mechanical cooperative system is proposed based on the reserge waveform. Various distortions of waveform represent deteriorations of control performance and maneuvering feeling. In some cases, since there is a tradeoff between the control performance and the maneuvering feeling, it is difficult to compensate for both of them by usual feedback controllers. To overcome this situation, the two degrees of freedom control system is applied to human-mechanical cooperative system. Some numerical simulation results for an electric power steering system are shown to confirm the effectiveness of proposed control design method.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.6
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• pp.52-64
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• 1996

This paper presents an active position control of a single-rod cylinder system featuring an electrorheological(ER) fluid-based valve. The ER fluid consisting of silicone oil and chemically treated particles is firstly composed and its Bingham property is tested as a function of imposed electric field. A multi-channel plate type of ER valve is then designed and manufactured on the basis of the field-dependent Bingham model. Performance test of the ER valve is undertaken by evaluating pressure drop with respect to the number of electrode as well as the intensity of the electric field. Subsequently, the ER valve-cylinder system is constructed and its governing equation of motion is derived. A neural control scheme for position control of the cylinder is formulated by incorporating proportional-plus-derivative(PD) controller and implemented. Experimental results of both regulating and tracking control responses are presented in order to demonstrate the efficacy of the proposed ER valve-cylinder control system.

• Journal of Electrical Engineering and Technology
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• v.2 no.4
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• pp.505-512
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• 2007

The object of this paper is to study a new control structure for sensorless induction machines dedicated to electrical drives using a three-level voltage source inverter VSI-NPC. The amplitude and the rotating speed of the flux vector can be controlled freely. The scheme investigated is an Enhanced direct torque control "EDTC" for electric vehicle propulsion. The considered application imposes some constraints which are achieved in EDTC control (fast torque response, optimal switching logic, torque control at zero speed, and large speed control. The results obtained for an induction motor indicate superior performance over the FOC type without need for any mechanical sensor.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.6
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• pp.72-81
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• 1999

A nonlinear engine torque and speed control algorithm using throttle angle control is developed with an engine load torque estimation algorithm. Three 3-dimensional nonlinear engine maps as a part of the nonlinear control algorithm are obtained from steady state engine dynamometer tests. An electric throttle actuator is developed using a stepper motor and a 8 bit micro-processor. The speed control and external load estimation algorithm are tested via engine speed control experiments, and show performance good enough for using various engine torque and speed control applications.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.4
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• pp.175-182
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• 2018

In recent years, micro-grid has been widely focused on the fields of renewal energy systems. This paper proposes a novel robust power converter control against arbitrary electric load changes for islanded micro-grid topology. First, we provide a state-space representation of our micro-grid model including power converter and electric load circuit. And then a state feedback control method is applied to construct a nominal control framework. Next, we propose a robust adaptive control law to enhance a control performance against unexpected load perturbation. In addition, we analytically investigate a passivity property for the micro-grid model and carry out computer simulation to demonstrate superiority and reliability of the proposed control methodology.

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.187-188
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• 2008

주기적으로 제어 성능을 평가하고, 평가 결과에 따라서 제어시스템의 제어기 상수를 최적화하거나 제어 밸브와 같은 제어기기의 문제점들을 사전에 개선하고자하는 노력이 있어왔다. 제어성능 평가방법은 제어목표 값에 대한 추종성을 평가하는 Set Point Analysis 방법을 주로 사용한다. 평가 지표는 Integral Absolute Error(IAE)와 같은 Error Integral 값과 Minimum Variance 방법이 실용적으로 사용된다. 본 논문에서는 평가 대상시스템으로 원자력발전소의 수위 제어시스템중 하나를 선정하고 Control Performance Assessment를 수행하였다. 이를 기반으로 대상 시스템의 제어모델링을 바탕으로 한 Minimum Integral Error를 만족하는 제어기 상수를 구하였으며 새로운 상수를 제어기에 설정한 후 다시 성능을 평가하였다. 평가 결과, 제어시스템의 제어 성능 평가 지표를 사용한 제어 루프의 평가와 예방 조치가 실제적으로 발전소의 안정적 운전에 유용하다는 것을 입증하였다.

• Journal of Korean Clinical Nursing Research
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• v.14 no.2
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• pp.47-57
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• 2008

Purpose: The purpose of this study was to examine the effects of an electric heating pad on abdominal pain and anxiety during the colonoscopy procedure. Method: Data were collected from 70 adult patients (experimental group (35), control group (35)) who underwent colonoscopy in a general hospital in Seoul, South Korea between January 6 and May 4 2006. For the experimental group the electric heating pad was applied from 20 minutes before the test through the whole procedure. Objective pain was measured during the test, and subjective pain, state anxiety, blood pressure and pulse rate were measured after the procedure. Results: The experimental group with the electric heating pad reported significantly lower subjective pain and anxiety than did the control group. There were no significant differences in objective pain between experimental and control groups. Patients with an electric heating pad showed significantly lower systolic and diastolic pressure than did those in the control group. There was no significant difference in pulse rate between the groups. Conclusion: Use of an electric heating pad was efficient in reducing subjective pain and anxiety among patients undergoing colonoscopy. This is a convenient and useful nursing intervention to reduce anxiety and pain among patients having a colonoscopy.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1483-1488
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• 2005

As the development of microprocessor technology, electric power steering(EPS) system which uses an electric motor came to use a few years ago. It can solve the problems associated with hydraulic power steering. The motor only operates when steering assistance is needed, so it can save fuel and can reduce weight and cost by eliminating hydraulic pump and piping. As one of performance criteria of EPS systems, the transmissibility from road wheel load to steering wheel torque is considered in this paper. The transmissibility can be studied by fixing the steering wheel and calculating the torque needed to hold the steering wheel from road wheel load. A proportion-plus-derivative control is needed for EPS systems to generate desired static torque boost and avoid transmissibility of fluctuation. A pure proportion control can' satisfy both requirements.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.812-815
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• 2003

Most of all, DTC drive is very simple in its implementation because it needs only two hysteresis comparator and switching vector table for both flux and torque control. The switching strategy of a conventional direct torque control scheme which is based on hysteresis comparator results in a variable switching frequency which depends on the speed, flux, stator voltage and the hysteresis of the comparator. The amplitude of hysteresis band greatly influences on the drive performance such as flux and torque ripple and inverter switching frequency. In this paper the influence of the amplitudes of flux and torque hysteresis bands and sampling time of control program on the torque and flux ripples are investigated. Simulation results confirm the superiority of the DTC under the proposed method over the conventional DTC.

• The Journal of Information Systems
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• v.31 no.4
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• pp.47-73
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• 2022

Purpose The purpose of this study is to select the electronic architecture concept of the powertrain domain of the electronic platform to be applied to electric vehicles after 2025. Previously, the automotive electrical and electronic architecture was determined only by trend analysis, but the purpose was to determine the scenario based on the data and select it with clear evaluation indicators. Design/methodology/approach This study identified the function to be applied to the powertrain domain of next-generation electric vehicle, estimated the controller, defined the function feature list, organized the scenario candidates with the controller list and function feature list, and selected the final architecture scenario. Findings According to the research results, the powertrain domain of electric vehicles was selected as the architectural concept to apply the DCU (Domain Control Unit) and VCU (Vehicle Control Unit) integrated architecture to next-generation electric vehicles. Although it is disadvantageous or equivalent in terms of cost, it was found to be excellent in most indicators such as stability, security, and hardware demand.