• 한국정밀공학회지
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• 제19권11호
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• pp.167-173
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• 2002

The look up table method conventionally applied to control the inner temperature and humidity of a laver drying machine has repeatedly occurred not only laver's damage but also inferior goods since the reaching time at the optimum state takes a long time. In this paper, a fuzzy control theory instead of the look up table was proposed to reduce the reaching time at the optimum state. The proposed method used six input variables and four output variables for the fuzzy control, and a triangle rule for a fuzzifier, The Mandani's min-max method was applied to a fuzzy inference. Also, the mean method of maximum was applied to a defuzzifier. The method applied to the fuzzy controller contributed to reduce the reaching time at the optimum state, and to minimize not only laver's damage but also inferior goods.

• Journal of Electrical Engineering and Technology
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• 제13권3호
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• pp.1304-1316
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• 2018

An adaptive sliding-mode observer for speed estimation in sensorless vector controlled induction machine drives is proposed in this paper to balance the dilemma between the requirement of fast reaching transient and the chattering phenomenon reduction on the sliding-mode surface. It is well known that the sliding-mode observer (SMO) suffers from the chattering phenomenon. However, the reduction of the chattering phenomenon will lead to a slow transient process. In order to balance this dilemma, an adaptive exponential reaching law is introduced into SMO by optimizing the reaching way to the sliding-mode surface. The adaptive exponential reaching law is based on the options of an exponential term that adapts to the variations of the sliding-mode surface and system states. Moreover, the proposed sliding-mode observer considering adaptive exponential reaching law, which is called adaptive sliding-mode observer (ASMO), is capable for reducing the chattering phenomenon and decreasing the reaching time simultaneously. The stability analysis for ASMO is achieved based on Lyapunov stability theory. Simulation and experimental results both demonstrate the correctness and the effectiveness of the proposed method.

• Physical Therapy Rehabilitation Science
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• 제11권2호
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• pp.145-153
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• 2022

Objective: The purpose of this study was to evaluate the Electromyography (EMG) of the upper limb during reaching tasks according to two heights in the sitting position. Design: Cross sectional design Methods: Fifteen hemiplegia, fifteen elderly, and fifteen healthy subjects have participated in this study. The targets (90% length of the subject's arm) were located at the two heights (the eye and xiphoid process). We have recorded EMG signals of seven upper limb muscles (anterior deltoid (AD), posterior deltoid (PD), pectoralis major (Pec), infraspinatus (Inf), supraspinatus (Sup), biceps brachii (Bi), triceps brachii (Tri)). The dependent variables were movement time(s), modulation ratio, working ratio, and the co-contraction ratio of the hemiplegia, elderly, and healthy at the reaching task. Two-way repeated-measures ANOVA (2-heights) was analyzed with the LSD post hoc test. Results: The study results were as follows: (1) The movement time to the target during reaching movement was significantly longer for the hemiplegia and elderly groups compared to the healthy group. (2) The modulation rate was significantly higher at eye height than the xiphoid height in AD, PD, Pec, Inf, Bi muscles, and the hemiplegia group and elderly group were significantly lower than the healthy group. Additionally, the modulation ratio showed a significant interaction between heights and groups. Conclusions: It is expected that the variables using the muscle contraction characteristics, the evaluation method of this study, can be used as an electromyography-based feedback method that can be objectively evaluated and quantified in clinical practice.

• 한국지능시스템학회논문지
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• 제8권5호
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• pp.21-28
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• 1998

본 논문은 고정 슬라이딩면을 갖는 가변 구조 제어기의 단점인 도달영역에서의 파리미터의 불확실성과 외부 외란에 대한 민간성을 감소시키는 방안으로 고정 슬라이딩면 대신 비선형 퍼지 슬라이딩면을 제시한다. 비선형 퍼지 슬라이딩면을 통하여 시스템 상태 궤적이 초기 위치에서부터 평형점에 이르기까지 외란과 파라미터의 불확실성에 강인하게 되며 아울러 고정 슬라이딩면까지의 도달시간 뿐만 아니라 평형점까지의 도달시간도 감소하게 되는 특성을 보이고자 한다. 본 논문은 회전 역진자을 이용한 시뮬레이션을 통해 제안된 알고리즘을 적용하여 타당성을 입증하였다.

• 대한전기학회논문지
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• 제36권1호
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• pp.52-57
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• 1987

In this paper, a methodology is developed to remove the reaching phase and the high frequency chattering phenomenon which are the common drawbacks of variable structrue control (VSC) system. A time varying switching surface is proposed to achieve sliding motion during the entire control process and a continuous control law whose terms are continuous functions inside a boundary layer neighbouring the time varying switching surface is developed to remove the high frequency chattering phenomenon of VSC. The methodology developed in this paper is applied to the 2'nd order time varying system and the simulated results are compared with those of typical VSC methodology.

• 한국산학기술학회논문지
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• 제11권3호
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• pp.835-840
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• 2010

본 논문은 가변 구조 제어기의 단점인 도달영역에서의 파리미터의 불확실성과 외부 외란에 대한 민감성을 감소시키는 방안으로 DNP제어를 제시한다. 비선형 동적 매니퓰레이터를 통하여 시스템의 상태 궤적이 초기 위치에서부터 평형점에 이르기까지 외란과 파라미터의 불확실성에 강인하게 되며 아울러 목표 직각 좌표까지 도달시간 뿐만 아니라 평형점까지의 도달시간도 감소하게 되는 특성을 보이고자 한다. 제안된 제어 구조의 효과는 시뮬레이션을 통해 증명하였다.

• 한국전문물리치료학회지
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• 제15권3호
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• pp.44-52
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• 2008

The purpose of this study was to investigate the effects of different objects and target location of dominant hand on the non-dominant hand movement kinematics in a bimanual reaching task. Fifteen right-handed volunteers were asked to reach from same starting point to the different target point of right and left hand with grasping the objects of different size. Independent variables were 1) three different object types (small mug cup, name pen, and PET bottle), and 2) three different target locations (shorter distance, same distance, and longer distance than the non-dominant hand) of the dominant hand. Dependent variables were movement time (MT), movement distance (MD), movement mean velocity ($MV_{mean}$), and movement peak velocity ($MV_{peak}$) of the non-dominant hand. Repeated measures two-way analysis of variance (ANOVA) was used to test for differences in the non-dominant hand movement kinematics during bimanual reaching. The results of this study were as follows: 1) MT of the non-dominant hand was increased significantly when traveling with grasping the mug cup and reaching the far target location, and was decreased significantly when traveling with grasping the PET bottle and reaching the near target location of the dominant hand. 2) MD of the non-dominant hand was significantly increased during reaching the far target location, and significantly decreased during reaching the near target location with dominant hand. 3) $MV_{mean}$ of the non-dominant hand was increased significantly when traveling with grasping the PET bottle, and was decreased significantly when traveling with grasping the mug cup of the dominant hand. Therefore, it can be concluded that the changes of the ipsilateral hand movement have influence on coupling of the contralateral hand movement in bimanual reaching.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.151.4-151
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• 2001

Chattering-free sliding mode control is derived from the reaching law method and Lyapunov stability theorem. Its control input Is composed of continuous term and discontinuous term. By the combination of these terms, the robustness and tracking performance can be improved and the chattering can be avoided. But in the reaching mode, the sliding mode control is sensitive to the modeling uncertainties, parameter variations and disturbances, also it needs a large control input. These result in poor transient responses. In this paper, to overcome these problems in the reaching mode, a time-varying sliding surface is proposed. And it is applied to a 2-link SCARA robot manipulator, experimental results show that the transient response is improved and its ...

• 한국산학기술학회논문지
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• 제10권12호
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• pp.3622-3625
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• 2009

본 논문은 고정 슬라이딩면을 갖는 가변 구조 제어기의 단점인 도달영역에서의 파리미터의 불확실성과 외부 외란에 대한 민감성을 감소시키는 방안으로 고정 슬라이딩면 대신 비선형 슬라이딩면을 제시한다. 비선형 슬라이딩면을 통하여 시스템 상태 궤적이 초기 위치에서부터 평형점에 이르기까지 외란과 파라미터의 불확실성에 강인하게 되며 아울러 고정 슬라이딩면까지의 도달시간 뿐만 아니라 평형점까지의 도달시간도 감소하게 되는 특성을 보이고자한다. 제안된 제어 구조의 효과는 시뮬레이션을 통해 증명하였다.

• 대한산업공학회지
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• 제32권4호
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• pp.369-372
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• 2006

Suppose that a customer arrives at the GI/M/1/K queueing system when there are customers in the system, $n,m{\geq}0,\;n+m{\leq}K$. Sooner or later, the number of customers in the system will reach . In this paper, we present the Laplace transform of the remaining interarrival time upon reaching level, for the first time, since a customer arrived when there are customers in the system.