• Title/Summary/Keyword: Optimal Parameter

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Identification and Control of Position Control System for Electro-Hydraulic Actuator (EHA) (EHA(Electro-Hydrostatic Actuator) 위치제어 시스템의 모델링 및 제어)

  • Park, Y.H.;Park, S.H.
    • Journal of Power System Engineering
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    • v.15 no.2
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    • pp.69-77
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    • 2011
  • In this paper, an optimal PID sliding mode controller is proposed for the position control of electro-hydrostatic actuator(ERA) systems with system uncertainties and saturation in the motor. An ERA prototype is developed and system modeling and parameter identification are executed. Then, optimal PID and optimal anti-windup PID controller are designed based on identified system model by using optimization toolbox in MA TLAB/Simulink and the performance of the two control systems are compared by experiment. It was found that the optimal anti-windup PID control system has better performance than the optimal anti-windup PID control system.

Fuzzy sliding-mode control of a human arm in the sagittal plane with optimal trajectory

  • Ardakani, Fateme Fotouhi;Vatankhah, Ramin;Sharifi, Mojtaba
    • ETRI Journal
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    • v.40 no.5
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    • pp.653-663
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    • 2018
  • Patients with spinal cord injuries cannot move their limbs using their intact muscles. A suitable controller can be used to move their arms by employing the functional electrical stimulation method. In this article, a fuzzy exponential sliding-mode controller is designed to move a musculoskeletal human arm model to track an optimal trajectory in the sagittal plane. This optimal arm trajectory is obtained by developing a policy for the central nervous system. In order to specify the optimal trajectory between two points, two dynamic and static optimal criteria are applied simultaneously. The first dynamic objective function is defined to minimize the joint torques, and the second static optimization is offered to minimize the muscle forces at each moment. In addition, fuzzy logic is used to tune the sliding-surface parameter to enable an appropriate tracking performance. Simulation results are evaluated and compared with experimental data for upward and downward movements of the human arm.

Determination of optimal Conditions for a Gas Metal Arc Wending Process Using the Genetic Algorithm

  • Kim, D.;Rhee, S.
    • International Journal of Korean Welding Society
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    • v.1 no.1
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    • pp.44-50
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    • 2001
  • A genetic algorithm was applied to the arc welding process as to determine the near-optimal settings of welding process parameters that produce the good weld quality. This method searches for optimal settings of welding parameters through the systematic experiments without the need for a model between the input and output variables. It has an advantage of being capable to find the optimal conditions with a fewer number of experiments rather than conventional full factorial designs. A genetic algorithm was applied to the optimization of the weld bead geometry. In the optimization problem, the input variables were wire feed rate, welding voltage, and welding speed. The output variables were the bead height bead width, and penetration. The number of levels for each input variable is 16, 16, and 8, respectively. Therefore, according to the conventional full factorial design, in order to find the optimal welding conditions,2048 experiments must be performed. The genetic algorithm, however, found the near optimal welding conditions in less than 40 experiments.

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Optimization of the Gain Parameters in a Tracking Module for ARPA system on Board High Dynamic Warships

  • Pan, Bao-Feng;Njonjo, Anne Wanjiru;Jeong, Tae-Gweon
    • Journal of Navigation and Port Research
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    • v.40 no.5
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    • pp.241-247
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    • 2016
  • The tracking filter plays a key role in the accurate estimation and prediction of maneuvering a vessel's position and velocity when attempting to enhance safety by avoiding collision. Therefore, in order to achieve accurate estimation and prediction, many oceangoing vessels are equipped with the Automatic Radar Plotting Aid (ARPA) system. However, the accuracy of prediction depends on the tracking filter's ability to reduce noise and maintain a stable transient response. The purpose of this paper is to derive the optimal values of the gain parameters used in tracking a High Dynamic Warship. The algorithm employs a ${\alpha}-{\beta}-{\gamma}$ filter to provide accurate estimates and updates of the state variables, that is, positions, velocity and acceleration of the high dynamic warship based on previously observed values. In this study, the filtering coefficients ${\alpha}$, ${\beta}$ and ${\gamma}$ are determined from set values of the damping parameter, ${\xi}$. Optimization of the damping parameter, ${\xi}$, is achieved experimentally by plotting the residual error against different values of the damping parameter to determine the least value of the damping parameter that results in the optimum smoothing coefficients leading to a reduction in the noise corruption effect. Further investigation of the performance of the filter indicates that optimal smoothing coefficients depend on the initial and average velocity of the target.

An Optimization Method of Neural Networks using Adaptive Regulraization, Pruning, and BIC (적응적 정규화, 프루닝 및 BIC를 이용한 신경망 최적화 방법)

  • 이현진;박혜영
    • Journal of Korea Multimedia Society
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    • v.6 no.1
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    • pp.136-147
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    • 2003
  • To achieve an optimal performance for a given problem, we need an integrative process of the parameter optimization via learning and the structure optimization via model selection. In this paper, we propose an efficient optimization method for improving generalization performance by considering the property of each sub-method and by combining them with common theoretical properties. First, weight parameters are optimized by natural gradient teaming with adaptive regularization, which uses a diverse error function. Second, the network structure is optimized by eliminating unnecessary parameters with natural pruning. Through iterating these processes, candidate models are constructed and evaluated based on the Bayesian Information Criterion so that an optimal one is finally selected. Through computational experiments on benchmark problems, we confirm the weight parameter and structure optimization performance of the proposed method.

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Parameter Estimation and Control for Apparatus of Container Crane;An Experimental Approach (모형 컨테이너 크레인의 파라미터 추정 및 제어;실험적 접근)

  • Lee, Yun-Hyung;Jin, Gang-Gyoo;So, Myung-Ok
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2007.12a
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    • pp.304-306
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    • 2007
  • In this paper, we presents a scheme for the parameter estimation and optimal control scheme for apparatus of container crane system. For parameter estimation, first, we construct the open loop of the container crane system and estimate its parameters based on input-output data, a real-coded genetic algorithm(RCGA) and the model adjustment technique. The RCGA plays an important role in parameter estimation as an adaptive mechanism. For controller design, state feedback gain matrix is searched by another RCGA and the estimated model. The performance of the proposed methods are demonstrated through a set of simulation and experiments of the experimental apparatus.

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Application of LQR for Phase-Locked Loop Control Systems

  • Khumma, Somyos;Benjanarasuth, Taworn;Isarakorn, Don;Ngamwiwit, Jongkol;Wanchana, Somsak;Komine, Noriyuki
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.520-523
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    • 2004
  • A phase-locked loop control system designed by using the linear quadratic regulator approach is presented in this paper. The system thus designed is optimal system when system is in locked state and the parameter value of loop filter which is an active PI filter can be obtained easily. By considering the structure of loop filter of phase-locked loop is included in the process to be controlled, a type 1 servo system can be constructed when voltage control oscillator is considered as an integrator. The integral gain of the proposed system obtained by linear quadratic regulator approach can be used as an optimal value to design the parameter of loop filter. The implemented result in controlling the second-order lag pressure process by using the proposed scheme show that the system response is fast with no overshoot and no steady-state error. Furthermore, the experimental results are also shown in term of output disturbance effect rejection, tracking and process parameter changed.

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An Experimental Study on the Optimal Arrangement of Cameras Used for the Robot's Vision Control Scheme (로봇 비젼 제어기법에 사용된 카메라의 최적 배치에 대한 실험적 연구)

  • Min, Kwan-Ung;Jang, Wan-Shik
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.19 no.1
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    • pp.15-25
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    • 2010
  • The objective of this study is to investigate the optimal arrangement of cameras used for the robot's vision control scheme. The used robot's vision control scheme involves two estimation models, which are the parameter estimation and robot's joint angle estimation models. In order to perform this study, robot's working region is divided into three work spaces such as left, central and right spaces. Also, cameras are positioned on circular arcs with radius of 1.5m, 2.0m and 2.5m. Seven cameras are placed on each circular arc. For the experiment, nine cases of camera arrangement are selected in each robot's work space, and each case uses three cameras. Six parameters are estimated for each camera using the developed parameter estimation model in order to show the suitability of the vision system model in nine cases of each robot's work space. Finally, the robot's joint angles are estimated using the joint angle estimation model according to the arrangement of cameras for robot's point-position control. Thus, the effect of camera arrangement used for the robot's vision control scheme is shown for robot's point-position control experimentally.

Establishment of the Parameter Range by Sensitivity Analysis and Determination of Optimal Parameter for Storage Function Model (저류함수모형의 민감도분석을 통한 경계조건 설정과 최적매개변수 결정에 대한 연구)

  • Song, Jae-Hyun;Kim, Hung-Soo;Hong, Il-Pyo;Kim, Sang-Ug;Kim, Bum-Jun
    • Proceedings of the Korea Water Resources Association Conference
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    • 2006.05a
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    • pp.1996-2000
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    • 2006
  • 현재 국내 주요 하천의 홍수예경보시스템 운영과 다목적댐의 홍수조절관리를 위하여 수문학적 모형의 하나인 저류함수모형(storage function model)을 사용하고 있다. 저류함수모형은 산지가 많은 유역에 적합하도록 개발된 모형으로, 계산절차가 간편하고 홍수유출의 비선형성을 고려할 수 있는 방법이므로 선형모형보다 합리적이라고 알려져 있다. 그러나 실제 홍수사상에 저류함수모형을 적용하기 위해서는 적절한 매개변수의 적용이 필요하다. 현재까지 저류함수모형의 매개변수를 보정하기 위한 연구가 많이 되었지만, 실질적으로 보정된 매개변수를 실제 홍수사상에 적용함에 있어서는 많은 어려움이 존재한다. 따라서 이러한 문제점을 해결하고자 본 연구에서는 저류함수 모형 중 유역유출 매개변수를 첨두유량에 대한 상대민감도분석을 통하여 매개변수의 경계조건을 설정하고, 이 경계조건을 바탕으로 최적화기법(optimization technique)을 사용하여 과거 홍수사상에 대하여 보정을 수행하였다. 그리고 보정된 매개변수를 모의 홍수사상에 적용하기 위한 최적매개변수(optimal parameter) 결정을 위한 방법들을 제시 및 적용하여 비교 분석하였다.

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The pH as a Control Parameter for Oxidation-Reduction Potential on the Denitrification by Ochrobactrum anthropi SY 509

  • Kim, Sung-Hong;Song, Seung-Hoon;Yoo, Young-Je
    • Journal of Microbiology and Biotechnology
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    • v.14 no.3
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    • pp.639-642
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    • 2004
  • The pH as a control parameter for oxidation-reduction potential (ORP) was investigated through the denitrification by Ochrobactrum anthropi SY509 under non-growing condition. The optimal pH of nitrate reductase was 7.0, and the minimal ORP level was -250 mV for the denitrification under aerobic condition. In the case of anaerobic condition, the optimal pHs of nitrate and nitrite reductase were shifted to 10.0 and 9.0, respectively, and the minimal ORP levels of nitrate and nitrite reductase were decreased to -370 mV and -340mV, respectively. In the case of alkaline pH and anaerobic condition, the denitrification efficiency of nitrate was increased up to about 2-fold over that of neutral pH and anaerobic condition. Therefore, the combined control of pH and ORP in the anaerobic condition is shown to be an important parameter in the biological denitrification process.