• Title/Summary/Keyword: weight sensor

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General Linearly Constrained Narrowband Adaptive Arrays in the Eigenvector Space

  • Chang, Byong Kun
    • Journal of information and communication convergence engineering
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    • v.15 no.3
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    • pp.137-142
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    • 2017
  • A general linearly constrained narrowband adaptive array is examined in the eigenvector space. The optimum weight vector in the eigenvector space is shown to have the same performance as in the standard coordinate system, except that the input signal correlation matrix and look direction steering vector are replaced with the eigenvalue matrix and transformed steering vector. It is observed that the variation in gain factor results in the variation in the distance between the constraint plane and the origin in the translated weight vector space such that the increase in gain factor decreased the distance from the constraint plane to the origin, thus affecting the nulling performance. Simulation results showed that the general linearly constrained adaptive array performed better at an optimal gain factor compared with the conventional linearly constrained adaptive array in a coherent signal environment and the former showed similar performance as the latter in a noncoherent signal environment.

Obtaining Design Characteristics of Lever-linked Roberval Mechanism through Weighing Method (무게측정방식에 따른 Lever-linked Roberval Mechanism의 설계특성)

  • An, Ji Yun;Ahn, Jung Hwan;Lee, Gil Seung;Kim, Hwa Young
    • Journal of Sensor Science and Technology
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    • v.29 no.5
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    • pp.336-341
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    • 2020
  • The deflection and null balance methods are used for precision force measurement in the precision industry. Since both methods are based on deformation, the performance of the load cell mechanism is important. In this study, the design variables were obtained via the free body diagram of a lever-linked Roberval mechanism (combined with a flexible hinge link and a Roberval mechanism), and the design characteristics were analyzed according to the weight method. Based on the design characteristics, the optimal design was conducted according to the weight method and FEM was used to verify its reliability.

MEMS GPS/INS Navigation System for an Unmanned Ground Vehicle Operated in Severe Environment (극한 무인 로봇 차량을 위한 MEMS GPS/INS 항법 시스템)

  • Kim, Sung-Chul;Hong, Jin-Seok;Song, Jin-Woo
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.2
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    • pp.133-139
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    • 2007
  • An unmanned ground vehicle can perform its mission automatically without human control in unknown environment. To move up to a destination in various surrounding situation, navigational information is indispensible. In order to be adopted for an unmanned vehicle, the navigation box is small, light weight and low power consumption. This paper suggests navigation system using a low grade MEMS IMU for supplying position, velocity, and attitude of an unmanned ground vehicle. This system consists of low cost and light weight MEMS sensors and a GPS receiver to meet unmanned vehicle requirements. The sensors are basically integrated by loosely coupled method using Kalman filter and internal algorithms are divided into initial alignment, sensor error compensation, and complex navigation algorithm. The performance of the designed navigation system has been analyzed by real time field test and compared to commercial tactical grade GPS/INS system.

Development and Evaluation of Broadband Piezoelectric Harvesters using a Cantilever-Type Module (캔틸레버형 모듈을 이용한 광대역 압전 하베스터 개발 및 평가)

  • Park, Buem-Keun;Paik, Jong-Hoo
    • Journal of Sensor Science and Technology
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    • v.29 no.4
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    • pp.261-265
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    • 2020
  • In cantilever type piezoelectric energy harvester, the amount of power generation decreases rapidly when outside a certain frequency. The thickness and weight of the cantilever metal plate were modified to develop cantilevers that could produce high power over a wide frequency range. The thicker the cantilever, the higher the power in the higher frequency range. As the weight of the mass increased, the cantilever tended to generate higher power, and the frequency band decreased. A 0.6 mm metal plate cantilever that had a mass of 3.3 g generated power that exceeded 3 mW within the 91-102 Hz range, with average and output values of 9.484 mW and 20.748 mW, respectively, at 99 Hz.

Selective weight control using minimum power configuration in wireless Sensor Network (무선 센서 네트워크에서 최소파워구성 방법을 이용한 선택적 웨이트 컨트롤 알고리즘)

  • Park, Do-Wook;Kim, Chong-Kwon
    • Proceedings of the Korean Information Science Society Conference
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    • 2006.10d
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    • pp.677-680
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    • 2006
  • 이 논문은 무선 센서 네트워크에서 최소 파워 구성 방법을 이용하여 에너지를 효율적으로 사용하면서 네트워크의 수명을 늘리고 지연(delay)을 줄이는 방안을 제시한다. 지금까지 에너지를 효율적으로 사용하기 위해 topology control, power-aware routing, sleep management 방법을 각각 독립적으로 연구되었는데 최소파워 구성은 위의 3가지 방법을 통합 최적화하여 에너지 효율적 사용 문제에 접근한다. 이러한 최소파워 구성 방법을 이용하여 선택적 웨이트 컨트롤(Selective weight control) 알고리즘을 제안하여 네트워크 전체 수명을 연장시키고 지연을 줄일 수 있다. 이 알고리즘은 각 노드가 주기적으로 잔류에너지를 인접노드들과 공유하여 에너지 랭크(rank)값을 유지한 상태에서 최소 에너지 경로를 사용하면서 에너지가 주위 노드들보다 작아질 때는 에너지가 많은 노드가 경로에 포함이 되도록 하여 특정 노드가 에너지 고갈되지 않고 네트워크내의 각 노드가 고르게 에너지를 소모하게 한다.

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Design of Digital Controller for the Levitation of Variable Steel Balls by using Magnetic Levitation System (자기부상 시스템을 이용한 임의의 금속구 부상을 위한 디지털제어기 설계)

  • Sa, Young-Ho;Yi, Keon-Young
    • Proceedings of the KIEE Conference
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    • 2001.07d
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    • pp.1940-1942
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    • 2001
  • Magnetic Levitation System(MLS) levitates a steel ball to the desired position in the gravity field using electromagnetic force. MLS consists of light sensor to measure the position of steel ball and an electromagnet to control the position of the ball, that composes a feedback control system. This work does not use a steel ball with constant mass but variable mass steel balls as magnetic levitation targets. Differential equation of electric circuit for electromagnet and motion equation of the movement of steel ball are derived for modeling nonlinear system, that will be linearized at the nominal operating point. We propose a digital control that can levitate a steel ball of which weight is not known for ED-4810 system. Algorithm for estimating ball weight and feedback control are implemented in digital scheme under pentium PC equiped with A/D and D/A converter, ACL-8112, using C-language. Simulation and experimental results are given to show the usefulness of the proposed controller.

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Yield Prediction of Chinese Cabbage (Brassicaceae) Using Broadband Multispectral Imagery Mounted Unmanned Aerial System in the Air and Narrowband Hyperspectral Imagery on the Ground

  • Kang, Ye Seong;Ryu, Chan Seok;Kim, Seong Heon;Jun, Sae Rom;Jang, Si Hyeong;Park, Jun Woo;Sarkar, Tapash Kumar;Song, Hye young
    • Journal of Biosystems Engineering
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    • v.43 no.2
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    • pp.138-147
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    • 2018
  • Purpose: A narrowband hyperspectral imaging sensor of high-dimensional spectral bands is advantageous for identifying the reflectance by selecting the significant spectral bands for predicting crop yield over the broadband multispectral imaging sensor for each wavelength range of the crop canopy. The images acquired by each imaging sensor were used to develop the models for predicting the Chinese cabbage yield. Methods: The models for predicting the Chinese cabbage (Brassica campestris L.) yield, with multispectral images based on unmanned aerial vehicle (UAV), were developed by simple linear regression (SLR) using vegetation indices, and forward stepwise multiple linear regression (MLR) using four spectral bands. The model with hyperspectral images based on the ground were developed using forward stepwise MLR from the significant spectral bands selected by dimension reduction methods based on a partial least squares regression (PLSR) model of high precision and accuracy. Results: The SLR model by the multispectral image cannot predict the yield well because of its low sensitivity in high fresh weight. Despite improved sensitivity in high fresh weight of the MLR model, its precision and accuracy was unsuitable for predicting the yield as its $R^2$ is 0.697, root-mean-square error (RMSE) is 1170 g/plant, relative error (RE) is 67.1%. When selecting the significant spectral bands for predicting the yield using hyperspectral images, the MLR model using four spectral bands show high precision and accuracy, with 0.891 for $R^2$, 616 g/plant for the RMSE, and 35.3% for the RE. Conclusions: Little difference was observed in the precision and accuracy of the PLSR model of 0.896 for $R^2$, 576.7 g/plant for the RMSE, and 33.1% for the RE, compared with the MLR model. If the multispectral imaging sensor composed of the significant spectral bands is produced, the crop yield of a wide area can be predicted using a UAV.

A study of weld monitoring using light emission in Aluminum 6K31 laser welding (알루미늄 6K31의 레이저 용접에서 Light Emission을 이용한 용접부 모니터링에 관한 연구)

  • 박영환;이세헌;박현성;신현일
    • Proceedings of the KWS Conference
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    • 2003.11a
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    • pp.52-54
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    • 2003
  • In automotive industry, light weight vehicle is one of issues because of air pollution. Therefore, automotive manufacturers have tried to apply light materials such as aluminum to car body. Welding aluminum using laser has some advantages good weld quality and high productivity. In this study, light emission which is generated in aluminum 6k21 welding with laser is measured using photodiodes. Analysis of relationship between sensor signals of welding variables and formation of keyhole and plasma is performed.

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Compensation of Electric Field Interference for Fiber-optic Voltage Measurement System

  • Cho, Jae-Kyong
    • Transactions on Electrical and Electronic Materials
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    • v.9 no.2
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    • pp.84-88
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    • 2008
  • In this paper, we analyze the errors associated with electric field interference for fiber-optic voltage sensors working in a three-phase electric system. For many practical conductor arrangements, the electric filed interference may cause errors unacceptable for the accuracy requirements of the sensors. We devised a real time compensation method for the interference by introducing geometric and weight factors. We realized the method using simple electronic circuits and obtained the real time compensated outputs with errors of 1 %.

The Fiber Optic Gyroscope (I) (광섬유 자이로스코프 (I))

  • 이석정;배정철;홍창희
    • Journal of the Korean Institute of Navigation
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    • v.18 no.4
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    • pp.171-178
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    • 1994
  • Fiber optic gyroscopes must be a promising technology that can replace conventional mechanical ones based on the principle of inertia of spinning masses. The advantages of fiber optic gyroscopes over mechanical ones include low cost, light weight, compact size and fast turn-on time. We will apply them to fiber optic gyrocompass for ships. Fiber optic gyrocompass for ships requires the north-seeking accuracy of $15^{\circ}$/hr, earth rotation rate, or better. This article introduces the fiber optic gyroscope as rotation sensor in the fiber optic gyrocompass system for ships that is planed to develop in our laboratory.

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