• 제어로봇시스템학회논문지
• /
• 제22권2호
• /
• pp.126-132
• /
• 2016

The root-locus method is often employed when a controller is designed to find controller gain. It is usually used to determine one parameter gain while most controllers for industrial applications have more than one controller gain. For example PID controller has three controller gains, i.e. P, I, and D gains. Thus the conventional root-locus technique cannot complete the design of a controller with more than one controller gain. One way to overcome this drawback has been to apply the root-locus technique for one parameter while other parameters are assumed to be proportional to the parameter or to be constant. However this approach could lead to limited performance of the controller and if we try to adjust the proportional ratio or constants then it could be a long and tedious process of trial and error. Thus it is required to find an effective method for the root-locus technique to design controllers with more than one parameter. To this end this paper proposes an extended root-locus method for controllers with two parameters. In this paper Matlab is used as a computation tool to show the effectiveness of our method by solving examples numerically. As a result we obtained an extended root-locus illustrated in two-dimensional space for a control system with two parameters. The paper then presents how to find two controller gains based on this result of the extended root-locus. The main idea is that we can find the parameters by approaching the desired poles. It is expected that the proposed idea will help control engineers to easily design control systems using the root-locus technique, resulting in more accurate and faster control systems. Note that the extended root-locus idea can be applied to controller design problems with multiple parameters.

• 드라이브 ㆍ 컨트롤
• /
• 제15권1호
• /
• pp.28-37
• /
• 2018

When the wind speed rises above the rated wind speed, the produced power of the wind turbines exceeds the rated power. Even more, the excessive power results in the undesirable mechanical load and fatigue. A solution to this problem is pitch control of the wind turbines. This paper presents a systematic design method of a collective pitch controller for the wind turbines using a discrete fuzzy Proportional-Integral (PI) controller. Unlike conventional PI controllers, the fuzzy PI controller has variable gains according to its input variables. Generally, tuning the parameters of fuzzy PI controller is complex due to the presence of too many parameters strongly coupled. In this paper, a systematic method for the fuzzy PI controller is presented. First, we show the fact that the fuzzy PI controller is a superset of the PI controller in the discrete-time domain and the initial parameters of the fuzzy PI controller is selected by using this relationship. Second, for simplicity of the design, we use only four rules to construct nonlinear fuzzy control surface. The tuning parameters of the proposed fuzzy PI controller are also obtained by the aforementioned relationship between the PI controller and the fuzzy PI controller. As a result, unlike the PI controller, the proposed fuzzy PI controller has variable gains which allow the pitch control system to operate in broader operating regions. The effectiveness of the proposed controller is verified with computer simulations using FAST, a NREL's primary computer-aided engineering tool for horizontal axis wind turbines.

• Smart Structures and Systems
• /
• 제3권1호
• /
• pp.115-131
• /
• 2007

The electromechanical integrated toroidal drive is a new drive system. For the control of the drive, the torque fluctuation and the steady-state errors should be removed and the fast response to the input change should be achieved. In this paper, the torque fluctuation of the drive system is analyzed and expressed as Fourier series forms. The transfer function of the torque control for the drive system is derived from its electromechanical coupled dynamic equations. A 2-DOF control method is used to control the drive system. Using definite parameter relationship of the 2-DOF control system, the steady errors of the torque control for the drive system is removed. Influences of the drive parameters on the control system are investigated. Using proper drive parameters, the response time of the control system is reduced and the quick torque response of the drive system is realized. Using a compensated input voltage, the torque fluctuation of the drive system is removed as well. The compensated input voltage can be obtained from the torque fluctuation equation and the transfer function. These research results are useful for designing control system of the new drive.

• 한국컴퓨터정보학회논문지
• /
• 제20권11호
• /
• pp.39-46
• /
• 2015

In this paper, we propose a performance-aware workload model for efficient implementation of control systems. When implementing a control algorithm as an embedded computer system, the control code executes periodically. For such systems, its control performance depends on not only the accuracy of the control algorithm itself but also temporal parameters such as control period and sensing to actuation delay. In this regard, this paper studies the relation between control period and delay by measuring and analyzing the control performance of LKAS (Lane Keeping Assist System) with varying period and delay combinations. Through this experimental study, this paper shows that the two timing parameters, i.e.,control period and delay, has a tradeoff relation in terms of control performance.

• 비파괴검사학회지
• /
• 제23권1호
• /
• pp.21-29
• /
• 2003

실시간 로봇 위치 제어를 위해 비젼시스템을 사용할 때 이 모델에 포함된 매개변수를 추정하는데 있어 계산시간을 줄이는 것은 매우 중요하다. 불행히도 흔히 사용되고 있는 일괄 처리 기법은 반복적으로 계산이 수행되기 때문에 많은 계산 시간을 필요로 하여 실시간 로봇 위치 제어를 어렵게 한다. 반면에 본 연구에서 사용하고자 하는 화장 칼만 필터링은 사용하기 편리하고, 또한 순환적 방법으로 계산되기 때문에 비젼시스템의 매개변수를 계산하는데 있어 시간을 줄이는 커다란 장점을 가지고 있다. 따라서 본 연구에서는 실시간 로봇 위치 제어를 위해 사용하는 비젼 제어 기법에 확장 칼만 필터링을 적용되었다 여기서 사용된 비젼시스템 모델은 카메라 내부 매개변수(방향, 초점거리 등) 및 외부 매개변수(카메라와 로봇 사이의 상대적 위치)를 설명하기 위해 6개 매개변수를 포함하고 있다. 이러한 매개변수를 추정하기 위해 확장 칼만 필터링 기법이 적용되었다. 또한 이렇게 추정된 6개 매개변수를 사용하여 로봇을 구동시키기 위해 필요한 로봇 회전각 추정에도 화장 칼만 필터링 기법이 적용되었다. 최종적으로 확장 칼만 필터링을 사용하여 개발된 비젼 제어 기법의 타당성을 로봇 위치 제어 실험을 수행하여 확인하였다.

• Computers and Concrete
• /
• 제11권2호
• /
• pp.105-121
• /
• 2013

This paper investigates the parameters that control the design of Fiber Reinforced Polymer (FRP) reinforced concrete flexural members proportioned following the ACI 440.1R-06. It investigates the critical parameters that control the flexural design, such as the deflection limits, crack limits, flexural capacity, concrete compressive strength, beam span and cross section, and bar diameter, at various Mean-Ambient Temperatures (MAT). The results of this research suggest that the deflection and cracking requirements are the two most controlling limits for FRP reinforced concrete flexural members.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2003년도 하계종합학술대회 논문집 V
• /
• pp.2569-2572
• /
• 2003

In this paper, we Proposed the inverted pendulum control method using single neuron neural network that have weights as PID parameters. The proposed method has three inputs(proportion, integration, differentiation term of the error), and uses weights as P, I, D parameters. In order to verify the effectiveness of the proposed method, we experimented on the rotary inverted pendulum with load effect disturbance. The results showed the effectiveness and robustness of the proposed pendulum controller.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
• /
• pp.164-167
• /
• 1996

This paper presents an off-line P.I.D parameter estimation method during normal operation in power plant. The process parameters are estimated using the recursive least square method. The controller parameters are estimated on the basis of desired characteristics of the dynamic model of the closed-loop control.

• 제어로봇시스템학회논문지
• /
• 제14권1호
• /
• pp.70-74
• /
• 2008

In the field of camera motion research, it is widely held that the position (movement) and pose (rotation) of cameras are correlated and cannot be independently separated. A new equation based on inner product is proposed here to independently separate the position and pose. It is proved that the position and pose are not correlated and the equation is applied to estimation of the camera exterior parameters using a real image and 3D data.

• Journal of Astronomy and Space Sciences
• /
• 제28권3호
• /
• pp.183-192
• /
• 2011

The current study analyzes the effects of the scaling parameters of the batch unscented transformation on precision satellite orbit determination. Satellite laser ranging (SLR) data are used in the orbit determination algorithm, which consists of dynamics model, observation model and filtering algorithm composed of the batch unscented transformation. TOPEX/Poseidon SLR data are used by utilizing the normal point (NP) data observed from ground station. The filtering algorithm includes a repeated series of processes to determine the appropriate scaling parameters for the batch unscented transformation. To determine appropriate scaling parameters, general ranges of the scaling parameters of ${\alpha}$, ${\beta}$, k, $\lambda$ are established. Depending on the range settings, each parameter was assigned to the filtering algorithm at regular intervals. Appropriate scaling parameters are determined for observation data obtained from several observatories, by analyzing the relationship between tuning properties of the scaling parameters and estimated orbit precision. The orbit determination of satellite using the batch unscented transformation can achieve levels of accuracy within several tens of cm with the appropriate scaling parameters. The analyses in the present study give insights into the roles of scaling parameters in the batch unscented transformation method.