• 한국자동차공학회논문집
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• 제24권3호
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• pp.294-301
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• 2016

This paper discusses about analyzing in-wheel vehicle's dynamic motion and load torque. Since in-wheel vehicle controls each left and right driving wheels, it is dangerous if vehicle's wheels are not in a cooperative control. First, this study builds the main wheel control logic using PID control theory and evaluates the stability. Using Carsim-Matlab/Simulink, vehicle dynamic motion is simulated in virtual 3D driving road. Through this, in-wheel vehicle's driving performance can be analyzed. The target vehicle is a rear-wheel drive in D-class sedan. Second, by using the first In-wheel vehicle's performance results, it derivate the drive motor's dynamic load torque for applying the dynamometer. Extracted load torque impute to dynamometer's load motor, linear experiment in dynamometer can replicated the 3-D road driving status. Also it, will be able to evaluate the more accurate performance analysis and stability, as a previous step of actual vehicle experiment.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.518-523
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• 2008

경부고속열차(KTX) 차량컴퓨터제어장치(OBCS : On Board Computer System)는 네트워크 통신을 이용하여 차량내 각 종 전장품의 동작상태 감시와 운행명령 및 열차제어, 차량의 유지보수, 승무원의 운전업무를 지원하는 장치로써 KTX의 핵심장치이다. 이 장치는 TGV 제작사양과 프랑스의 고속열차 운영방식에 종속되어 특화된 시스템으로 제작되었으므로 실질적인 기술이전이 어려운 상태이다. 그렇기때문에 KTX 국내도입 후 운영상 요구되는 기능개선 및 자체적인 유지보수, 각 종 전장품(추진제어장치, 보조전원장치, 출입문제어장치 등)의 국산화 교체시 대부분의 인터페이스 신호가 차량컴퓨터제어장치(OBCS)와 연계되어 있어 많은 어려움이 수반되고 있다. 따라서 본 연구에서는 KTX 차량컴퓨터제어장치의 기능분석 및 주변장치(기관사 콘솔, 여객정보시스템, 고장현시장치, 각종 전장품 등)와의 상호 인터페이스 정보분석을 통해 KTX-OBCS 국산화 개발을 함으로써 KTX 운영상 요구되는 기능개선 및 유지보수 효율화에 기여하고, 더 나아가 고속열차제어 및 전장품 분야에서 선진 외국기술의 종속을 탈피하여 기술자립화를 이루고자 한다.

• 한국항공우주학회지
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• 제33권2호
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• pp.84-91
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• 2005

오랜기간 비행선의 이착륙은 사람에 의한 수동으로 이루어졌으나, 자동제어시스템의 개발과 함께 이를 비행선에 적용하여 보다 정확한 이착륙의 필요성이 대두되었으며, 많은 알고리즘이 개발되고 있다. 본 논문에서는 기낭의 압력제어에 의한 비행선의 이착륙제어를 다룬다. 비행선의 운동방정식은 비선형 방정식으로 매우 복잡하여 우선 간단한 PID제어기에 의한 해법을 제시하였다. 그러나, 운항시 대기조건이 빠르게 변하므로 변하는 예측 불가능한 외란에 대해서는 만족스런 성능을 보이지 못하였다. 따라서, 본지에서는 인공 신경망을 이용한 학습알고리즘을 토대로 원하는 궤적에 빠르게 추종하도록 설계하였다. 일반적으로 인공신경망은 복잡한 문제에 있어서 많은 수의 은닉층과 뉴런이 필요하고 또한 훈련시간이 많이 걸리는 단점이 있기에 이를 해결하기 위해 비행선 이착륙 문제에 대한 일반적인 인공신경망 적용에 대해 연구하였다. 본지에서는 RBFN(radial basis function network)제어기를 설계하였고, 신경 회로망의 가중치는 외란이 인가되거나 부하특성이 비선형적으로 변화되는 것을 고려하도록 기준입력과 실제 비행선 모델의 출력사이의 오차를 최소화하는 방향으로 학습을 진행하였다. 그 결과 최대 15m의 오차를 보이는 PID제어기보다 양호한 결과를 얻었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2606-2611
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• 2003

Comprehensive study on the control system design for a RTP process has been conducted. The purpose of the control system is to maintain maximum temperature uniformity across the silicon wafer achieving precise tracking for various reference trajectories. The study has been carried out in two stages: thermal balance modeling on the basis of a semi-empirical radiation model, and optimal iterative learning controller design on the basis of a linear state space model. First, we found through steady state radiation modeling that the fourth power of wafer temperatures, lamp powers, and the fourth power of chamber wall temperature are related by an emissivity-independent linear equation. Next, for control of the MIMO system, a state space modeland LQG-based two-stage batch control technique was derived and employed to reduce the heavy computational demand in the original two-stage batch control technique. By accommodating the first result, a linear state space model for the controller design was identified between the lamp powers and the fourth power of wafer temperatures as inputs and outputs, respectively. The control system was applied to an experimental RTP equipment. As a consequence, great uniformity improvement could be attained over the entire time horizon compared to the original multi-loop PID control. In addition, controller implementation was standardized and facilitated by completely eliminating the tedious and lengthy control tuning trial.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.333-336
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• 2003

For long time, the takeoff and landing control of airship was worked by human handling. With the development of the autonomous control system, the exact controls during the takeoff and landing were required and lots of methods and algorithms were suggested. This paper presents the result of airship take-off and landing by buoyancy control using air ballonet volume change and performance control of pitch angle for stable flight within the desired altitude. For the complexity of airship's dynamics, firstly, simple PID controller was applied. Due to the various atmospheric conditions, this controller didn’t give satisfactory results. Therefore, new control method was designed to reduce rapidly the error between designed trajectory and actual trajectory by learning algorithm using an artificial neural network. Generally, ANN has various weaknesses such as large training time, selection of neuron and hidden layer numbers required to deal with complex problem. To overcome these drawbacks, in this paper, the RBFN (radial basis function network) controller developed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.202-207
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• 1993

A theoretical and experimental study is presented for the force holding control of a miniature robotic ringer which is driven by a pair of piezoelectric unimorph cells. In the theoretical analysis, one finger is modeled as a flexible cantilever with a tactile force sensor at the tip and the mate of the finger is a solid beam supposed with sufficient stiffness. Further, the force sensor is modeled by a one-degree-of-freedom, mass-spring system and the output of sensor is then described by the sensor stiffness multiplied by the relative displacement. The problem investigated in this paper is that two typical holding tasks of the human finger are picked up and applied to the robotic finger. One is the work holding a stationary object with a prescribed, time-varying force and the other one is to keep the contacted force constant even if the object is in motion. The simple PID feedback control scheme is used to control the minute gripping force of order 0.01 Newton. It is shown both experimentally and theoretically that the artificial finger with the piezoelectric actuator works well in the minute force holding of the tiny object.

• Journal of Biosystems Engineering
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• 제21권4호
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• pp.422-428
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• 1996

This study was conducted to developed to develop a simple battery-powered autonomous vehicle for greenhouse works. A steering method using speed difference of two independent driving motors was adopted. DC motor driving circuit, speed control circuit and controller using one-chip microcomputer were constructed. The inputs of controller are rolling of the vehicle and current speed of driving motors. Using these signals, automatic guidance system along furrow was developed. A computer simulation program by the kenematic analysis was developed to find out optimal control algorithm. The results of this study are as follows. 1. Automatic guidance system along the furrow that adopted two independent driving motors and rolling of vehicle was developed. 2. The results of simulation showed that PID control was adequate to automatic guidance system along furrow. 3. Two commercial 12V battery serially connected were able to drive the vehicle on the soil ground for five hours in continuous operation and for four hours in intermittent operation without recharging the battery. 4. The speed range was 0-0.7m/s and the rolling of vehicle could be controlled within $pm5^{\circ}$ range. 5. From a series of tests, developed vehicle was found to be a useful tool for greenhouse works.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.531-536
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• 2005

The purpose of this paper is to improve the hysteresis characteristics of a stack type piezoelectric actuator using system identification and tracking control. Recently, several printing methods that cost less and are faster than previous semiconductor processes have been developed for the production of electric paper and RFID. The system proposed in this study prints by spraying the molten metal, and consists of a nozzle, heating furnace, operating actuator, and an XYZ 3-axis stage, As an operating system, the piezoelectric(PZT) method has very valuable uses. However, the PZT actuator has a very big hysteresis characteristic due to the ferroelectric characteristics of the PZT element. This causes problems in the system position control characteristics and deteriorates the performance of the system. In this study, an investigation was conducted to improve the hysteresis characteristics of the PZT actuator that has an output displacement for the input voltage. The study proposed a inverse hysteresis model, a mathematic modeling method that can express the geometric relationship between voltage and displacement, in order to reduce the hysteresis of the PZT actuator. In addition, system identification and PID control methods were examined. Also, it was confirmed that the proposed control strategy gives good precision position control performance.

• 한국정밀공학회지
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• 제14권3호
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• pp.98-106
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• 1997

In this paper, a new method of position synchronizing control is proposed for multi-axes driving system. The proposed position synchronizing control system is constituted with speed and synchronizing controller. The speed controller is aimed at the following to speed reference. Furthermore, it is designed to guarantee low sensitivity under some disturbance as well as robustness against model uncertainties using $H_{\infty}$technique. The synchronizing controller is designed to keep minimizing the position error using PID control law which is considered to reduce the dimension of transfer function in the control system. Especially, the proposed method can be easily conducted by controlling only slave axis speed, because it, has variable structure which is decided to master and slave axis by the sign of synchronizing error. Therfore, the master axis which is smaller influenced than another axes by disturbance can be controlled without reducing or increasing its speed for precise position synchronization. The effectiveness of the proposed method is sucessfully confirmed through many experiments.s.

• 전기학회논문지
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• 제56권5호
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• pp.944-957
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• 2007

In general mechanical servo systems, friction deteriorates the performance of controllers by its nonlinear characteristics. Especially, friction phenomenon causes steady-state tracking errors and limit cycles in position and velocity control systems, even though gains of controllers are tuned well in linear system model. Even if sensor is used higher accuracy level, it is difficult to improve tracking performance of the position to the same level with a general control method such as PID type. Therefore, many friction models were proposed and compensation methods have been researched actively. In this paper, we consider that the variation of mover's mass is various by loading and unloading. The normal force variation occurs by it and other parameters. Therefore, the proposed control system is composed of main position controller and a friction compensator. A parameter estimator for a nonlinear friction model is designed by adaptive control law and adaptive backstopping control method.