• 대한기계학회논문집A
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• 제40권1호
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• pp.103-111
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• 2016

본 논문에서는 차량의 횡방향 안정성을 향상시키기 위해 자세 제어 장치(ESC)와 능동 전륜 조향(AFS)을 이용하는 통합 새시 제어의 적응 가변 가중치 조절 방법을 제안한다. 제어기 설계 방법론을 적용하여 차량을 안정화시키는데 필요한 제어 요 모멘트를 구한 후 이를 가중 역행렬 기반 제어 할당 방법(WPCA)을 이용하여 ESC 의 제동력과 AFS 의 추가 조향각으로 분배한다. 저마찰 노면에서는 차량의 속도가 높다면 횡슬립각이 증가하여 횡방향 안정성이 저하되므로 이를 방지하기 위해 WPCA 의 가변가중치를 상황에 따라 조절하는 방법을 제안한다. 차량 시뮬레이션 패키지인 CarSim 에서 시뮬레이션을 수행하여 제안된 방법이 통합 섀시 제어기의 횡방향 안정성을 향상시킨다는 사실을 검증한다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.343-347
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• 2008

Design of shape for visco-elastic vibration isolation elements, which are very cost-effective and so popular in many applications is frequently based on experiences, intuitions, or trial and errors. Such traditions in shape design make it difficult for drastic changes or new concepts to come out. In this paper, both topological method and shape optimization method are combined together to find out a most desirable isolator shape efficiently by using two commercial engineering programs. ABAQUS and MATLAB. The procedure is divided into two steps. At the first step, a topology optimization method is employed to find an initial shape. where density of either 0 or 1 for finite elements is used for physical realizability. At the second step, based on the initial shape, finer tuning of the shape is done by boundary movement method. An illustration of the procedure will be presented for a mount of an air-conditioner compressor system and the effectiveness will be discussed.

• 한국소음진동공학회논문집
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• 제18권12호
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• pp.1250-1255
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• 2008

Design of shape fur visco-elastic vibration isolation elements, which are very cost-effective and so popular in many applications is fi?equently based on experiences, intuitions, or trial and errors. Such traditions in shape design make it difficult for drastic changes or new concepts to come out. In this paper, both topological method and shape optimization method are combined together to find out a most desirable isolator shape efficiently by using two commercial engineering programs, ABAQUS and MATLAB. The procedure is divided into two steps. At the first step, a topology optimization method is employed to find an initial shape, where density of either 0 or 1 for finite elements is used fur physical realizability. At the second step, based on the initial shape, finer tuning of the shape is done by boundary movement method. An illustration of the procedure is presented fur a mount of an air-conditioner compressor system and the effectiveness is discussed.

• International Journal of Control, Automation, and Systems
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• 제5권6호
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• pp.691-700
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• 2007

This paper proposes a simple but effective design method of PID control using a numerical optimization method. In order to achieve both stability and performance, gain and phase margins and performance indices of step response directly compose of the cost function. Hence, the proposed approach is a multiobjective optimization problem. The main effectiveness of this approach results from the strong capability of the used optimization method. A one-dimensional example concerning gain margin illustrates the practical applicability of the optimization method. The present approach has many degrees of freedom in controller design by only adjusting related weight constants. The attained PID controller is compared with Wang#s and Ho#s methods, IAE, and ISE for a high-order process, and the simulation result for various design targets shows that the proposed approach achieves desired time-domain performance with a guarantee of frequency-domain stability.

• 제어로봇시스템학회논문지
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• 제11권5호
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• pp.463-470
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• 2005

This paper describes a method aimed at improving dead-reckoning accuracy with gyroscopes in mobile robots. The method is a precision calibration procedure for gyroscopes, which effectively reduces the ill effects of nonlinearity of the scale-factor and temperature dependency. This paper also describes the methods of gyro data collection fur all ambient temperature$(-40^{\circ}C{\~}+80^{\circ}C)$ using cubic spline interpolation and defining the error function. The sensor used was a vibrating gyroscope called the EWTS82NA21, which is low lost and commonly used in car navigation system, made by Panasonic. This angular rate sensor utilizes Coriolis force generated by a vibrating tuning fork. The paper also provides experimental results to check the performance and the effectiveness of the proposed method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.726-728
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• 1995

A servo control algorithm robust under disturbance and reference change is developed using the self tuning control method based on the concept of the least distribution control. Also, the design algorithm incorporates the concepts of the well known internal model principle and the annihilator polynomial. In order to evaluate the effectiveness of the method, MAGLEV (Magnetic Levitation) system is used and the position control experiment for reference changes and disturbances of step type is done.

• 한국경영정보학회:학술대회논문집
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• 한국경영정보학회 2007년도 International Conference
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• pp.582-587
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• 2007

ERP system is a good one because it provides required data to the Board of Directors at the right time, but needs to collect many data in this system. Nevertheless, increase in data leads to the system's quality deterioration which makes companies to carry out quality improvement. In order to solve quality deterioration problem, a company's quality improvement director must execute under acknowledgement of the relationships between sectors to be improved, which are DBMS, Application, System, Data Management, Archiving, and Reorganization. But in many cases, these relationships are ignored due to massive size of each of the sectors, resulting fragmental quality improvement operation. This case paper proposes a solution to effectively solve quality deterioration problem created by the massive data produced while operating ERP System(constructed by SAP package and web). First, it defines the sectors where quality improvements are vital, and lists out things to be considered. Then, by analysing the working process of these sectors, proposes the most efficient order of the improvement process. This case will eventually help the company's quality improvement director to execute quality improvement most effectively without trials and errors, which is this paper's ultimate goal.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 D
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• pp.650-652
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• 2000

Although Fuzzy Logic Controller(FLC) adopted three terms as input gives better performance. FLC is in general composed of two-term control because of the difficulty in the construction of fuzzy rule base. In this paper, a three-term FLC which is similar to PID control but acts as a nonlinear controller is proposed. To reduce the complexity of the rule base design and increase efficiency, a simplified fuzzy PID control is induced from a hybrid velocity/position type PID algorithm by sharing a common rule base for both fuzzy Pi and fuzzy PD parts. It is simple in structure, easy in implementation, and fast in calculation. The phase plane technique is applied to obtain the rule base for fuzzy two-term control and them. The resultant rule base is Macvicar-Whelan type. The frequency response information is used in tuning of membership functions. Also a tuning strategy for the scaling factors is Proposed based on the relationship between PID gain and them. Simulation results show better performance and the effectiveness of the proposed method.

• 산업기술연구
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• 제20권B호
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• pp.155-162
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• 2000

Although Fuzzy Logic Controller(FLC) adopted three terms as input gives better performance, FLC is in general composed of two-term control because of the difficulty in the construction of fuzzy rule base. In this paper, a three-term FLC which is similar to PID control but acts as a nonlinear controller is proposed. To reduce the complexity of the rule base design and to increase efficiency. a simplified fuzzy PID control is induced from a hybrid velocity/position type PID algorithm by sharing a common rule base for both fuzzy PI and fuzzy PD parts. It is simple in structure, easy in implementation, and fast in calculation. The phase plane technique is applied to obtain the rule base for fuzzy two-term control and the resultant rule base is Macvicar-Whelan type. And the membership function is a Gaussian function. The frequency response information is used in tuning of the membership functions. Also a tuning strategy for the scaling factors is proposed based on the relationship between PID gain and the scaling factors. Simulation results show better performance and the effectiveness of the proposed method.

• Smart Structures and Systems
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• 제2권1호
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• pp.1-24
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• 2006

The optimal design of multiple tuned mass dampers (multiple TMD's) to suppress multi-mode structural response of beams and floor structures was investigated. A new method using a numerical optimizer, which can effectively handle a large number of design variables, was employed to search for both optimal placement and tuning of TMD's for these structures under wide-band loading. The first design problem considered was vibration control of a simple beam using 10 TMD's. The results confirmed that for structures with widelyspaced natural frequencies, multiple TMD's can be adequately designed by treating each structural vibration mode as an equivalent SDOF system. Next, the control of a beam structure with two closely-spaced natural frequencies was investigated. The results showed that the most effective multiple TMD's have their natural frequencies distributed over a range covering the two controlled structural frequencies and have low damping ratios. Moreover, a single TMD can also be made effective in controlling two modes with closely spaced frequencies by a newly identified control mechanism, but the effectiveness can be greatly impaired when the loading position changes. Finally, a realistic problem of a large floor structure with 5 closely spaced frequencies was presented. The acceleration responses at 5 positions on the floor excited by 3 wide-band forces were simultaneously suppressed using 10 TMD's. The obtained multiple TMD's were shown to be very effective and robust.