• The Journal of the Convergence on Culture Technology
• /
• v.10 no.3
• /
• pp.801-807
• /
• 2024

Linear motion robots are devices that perform functions such as transferring parts or positioning devices, and require high precision. In companies that develop linear robot application systems, human workers are in charge of quality control and fault diagnosis of linear robots, and the result and accuracy of a fault diagnosis varies depending on the skill level of the person in charge. Recently, there have been many attempts to utilize artificial intelligence to diagnose faults in industrial devices. In this paper, we present a system that automatically diagnoses linear rail and ball screw misalignment of a linear robot using transfer learning. In industrial systems, it is difficult to obtain a lot of learning data, and this causes a data imbalance problem. In this case, a transfer learning model configured by retraining an established model is widely used. The information obtained by using an acceleration sensor and torque sensor was used, and its usefulness was evaluated for each case. After converting the signal obtained from the sensor into a spectrogram image, the type of abnormality was diagnosed using an image recognition artificial intelligence classifier. It is expected that the proposed method can be used not only for linear robots but also for diagnosing other industrial robots.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.17 no.12 s.115
• /
• pp.1164-1171
• /
• 2006

In this paper, a simple and nonlinear MMSE detector is derived from the conventional linear MMSE detector to improve the system performance in turbo processing MIMO system and a new turbo processing MIMO system with nonlinear MMSE detector and Gaussian approximation is proposed. In turbo coded turbo processing MIMO system, the proposed system of M=N=4 performs about 0.5 dB better than the conventional system and the proposed system of M=N=8 performs about 0.4 dB better than conventional system at 1 % FER. In addition, the average number of outer iterations of proposed system shows lower than that of conventional system. This is caused by the fact that the nonlinear MMSE detector of proposed system decides soft-outputs of coded bits based on the observation of received signals, so that it can reduce the uncertainty region in estimating the coded bits.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.19 no.11
• /
• pp.2291-2302
• /
• 1994

This paper shows the implementation and design of special processor for linearly shift knapsack public key cryptography system. We highten the density of existing knapsack vector and shift the vectors linearly in order to implement the structure of linearly shift knapsack system which has the stronger cryptosystem. As it needs the parallel processing at each path according to the characteristics of this system. we propose the pipelined parallel structure and implement this system into VLSL. Also we evaluate this system and compare with other systems. The processing speed of this system is 550kb/s when dimension is 100. It is possible to use this system at the place of requiring high speed security to enlarge the structure of it.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.15 no.2
• /
• pp.185-190
• /
• 2005

A systematic output tracking control design technique for robust control of Takagi-Sugeno (T-S) fuzzy systems with norm bounded uncertainties is developed. The uncertain T-S fuzzy system is first represented as a set of uncertain local linear systems. The tracking problem is then converted into the stabilization problem for a set of uncertain local linear systems thereby leading to a more feasible controller design procedure. A sufficient condition for robust asymptotic output tracking is derived in terms of a set of linear matrix inequalities. A stability condition on the traversing time instances is also established. The output tracking control simulation for a flexible-joint robot-arm model is demonstrated, to convincingly show the effectiveness of the proposed system modeling and controller design.

• Journal of the Korea Institute of Building Construction
• /
• v.11 no.1
• /
• pp.1-8
• /
• 2011

Linear scheduling method limits to present works of work breakdown structure as a form of lines and was often developed manually. In other words, linear schedule could not utilize activity, work breakdown structure, and etc. information of network schedule such as CPM(Critical Path Method) and has been used only for reporting or confirming construction master plan. Therefore, it is necessary to develop system which can automatically generating the linear schedule based on the network schedule having many accumulated and useful construction schedule information. Thus, this research has an effort to establish data process model, data flow diagram, and data model in order to make linear schedule. In addition, this research addresses the system solution structure, user interface class diagram and logic diagram, and data type schema. The results of this paper can be used as a preliminary research for developing linear schedule generating system prototype by utilizing the network schedule information.

• Journal of Navigation and Port Research
• /
• v.31 no.1 s.117
• /
• pp.55-64
• /
• 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 backstepping control method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.06a
• /
• pp.724-727
• /
• 2007

선박 운항 자동화 시스템은 선내 노동력 감소, 작업 환경 개선, 운항 안전성 확보 및 운항 능률의 향상을 목표로 하며, 궁극적으로는 운항 경제성확보를 위한 승선 인원의 최소화에 그 목적이 있다. 최근에는 적응 제어방법 등을 응용하여 선박의 비선형성을 보상하여 선박의 회두각 유지제어(Course Keeping Control), 항로 추적제어(Track Keeping Control), 롤-타각제어(Roll-Rudder Stabilization), 선박 위치제어(Dynamic Ship Positioning), 선박자동 접이안(Automatic Mooring Control) 등에 관한 연구를 수행하고 있으며 실제의 선박으로 대상으로 응용연구가 진행 중이다. 선박은 Steering Machine에 의해 조정되는 Rudder angle과 선박의 회두각의 관계는 비선형적이며, 선박의 Load Condition은 선박의 Parameter에 영향을 주는 비선형적인 요소로서 작용한다. 또한 외란요소인 파도의 유속(流速)과 방향, 풍속과 풍량 등이 비선형적인 형태로 작용하므로 선박의 운항을 힘들게 하는 요인이 된다. 따라서 선박의 운항시스템에는 비선형성을 극복할 수 있는 강인한 제어 알고리즘을 요구한다. 본 논문에서는 퍼지 알고리즘을 이용하여 선박의 비선형적인 요인 및 외란을 극복할 수 있는 선박의 자율운항 시스템을 설계하고 시뮬레이션을 통해 그 결과를 살펴보았다.

• Proceedings of the KIEE Conference
• /
• 2006.07d
• /
• pp.2057-2058
• /
• 2006

선형 전동기는 일반 회전기를 펼친 상태로 유도기, 전동기, 직류기 및 기타 특수 전동기로 분류하며 그 원리는 회전형 전동기와 같다. 직선 운동을 필요로 하는 시스템에서 기계적 변환 기구를 사용하지 않고 직접 직선 운동을 얻을 수 있으므로 향후 자동화 기기, 교통수단, 산업용 기기 등에 많은 수요를 창출할 수 있는 전동기이다. 또한 선형 전동기는 일반 회전형 전동기에 비해 스크류, 체인, 기어 시스템 등의 기계적인 변환장치가 없이 선형 구동력을 직접 발생시키므로 청정을 필요로 하는 환경에서 회전형에 비해 절대적으로 우세하다. 그러나 이상과 같은 장점을 지닌 선형 전동기를 실제 시스템에 적용하기 위해서는 속도의 저하에 따른 저 출력, 저 효율 및 고 가격과 같은 문제들을 우선적으로 해결해야 한다. 본 논문에서는 이 선형 전동기 기술이 적용되는 차세대 LCD 공정 자동화설비인 10,000N급 Stocker System에 적용되는 핵심기술과 기술개발 동향에 대한 소개를 하고자 한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.19 no.1
• /
• pp.64-69
• /
• 2005

In this paper, we analyzed the nonlinear performance on the DS/CDMA Communication System. At the $BER=10^{-4}$, uniform chip waveforms have similar performance in the linear channel. However, non-uniform chip waveforms have about more 0.5[dB] power gain than the conventional raised-cosine chip waveforms. In the nonlinear HPA, non-uniform chip waveforms have worse BER performance than the uniform chip waveforms because of the high PAPR. In other words, non-uniform chip waveforms show similar performance as uniform chip waveforms if IBO (input back on) of 15[dB] is given.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.26 no.6A
• /
• pp.965-979
• /
• 2001

본 논문에서는 OFDM 시스템의 송신기에서 사용되는 선형 필터와 고출력 증폭기의 결합에 의한 \"기억성을 갖는 비선형 왜곡\"을 실제 하드웨어 구현에 적합하게 적은 계산량으로 보상할 수 있는 참조 테이블(look up table; LUT) 기반의 사전왜곡기를 제안한다. LUT를 이용하는 사전왜곡기들은 이미 많이 연구되었으나, 본 논문에서는 다중 입력/단일 출력 형태의 기억성을 갖는 비선형 왜곡을 작은 크기의 LUT를 이용하여 효율적으로 보상한다는 점에서 큰 차이가 있다. 제안 방법에서는 먼저 기억성이 없는 고출력 증폭기만이 존재할 때의 사전왜곡기를 우리가 이미 제안한 고정점 반복 사전왜곡기 알고리즘에 기반하여 LUT로 구현하고, 여기에 선형 역 시스템을 결합하여 기억성을 갖는 비선형 왜곡을 보상한다. 실제 구현 가능성 검토를 위해 제안된 사전왜곡기와 16-QAM, 256-IFFT/FFT OFDM 시스템 기저대역 모뎀을 TMS320C30 DSP를 이용하여 구현하였으며, 실험 결과 작은 크기의 LUT를 이용하여도 원래의 고정점 반복 사전왜곡기에 비해 매우 적은 계산량을 요구하면서 동일한 성능을 얻을 수 있음을 확인하였다.있음을 확인하였다.