• Title/Summary/Keyword: signal control scheme

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DECENTRALIZE)) ADAPTIVE CONTROL FOR ROBOT MANIPULATOR (로보트 매니퓰레이터의 비집중 적응제어)

  • Lee, Sang-Cheol;Chung, Chan-Su
    • Proceedings of the KIEE Conference
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    • 1990.07a
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    • pp.504-509
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    • 1990
  • This paper presents a decentralized adaptive control scheme for multi-Joint robot manipulators based on the independent joint control scheme. The control object is to achieve accurate tracking of desired Joint trajectories. The proposed control scheme does not use the complex manipulator dynamic model, and each joint is controlled simple by a feedback controller which ensure stable and also a position-velocity-acceleration feedforward controller and also auxiliary signal, with adjustable gains. Simulation results are given for a two-link manipulator under independent control, proposed decentralized adaptive control of manipulator is feasible. In spite of a pay load variation and strong static and dynamic couplings that exist between the joints.

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Design of Fault Tolerant Control System for Steam Generator Using Fuzzy Logic

  • Kim, Myung-Ki;Seo, Mi-Ro
    • Proceedings of the Korean Nuclear Society Conference
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    • 1998.05a
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    • pp.321-328
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    • 1998
  • A controller and sensor fault tolerant system jot a steam generator is designed with fuzzy logic. A structure of the : proposed fault tolerant redundant system is composed of a supervisor and two fuzzy weighting modulators. A supervisor alternatively checks a controlled and a sensor induced performances to identify Which Part, a controller or a sensor, is faulty. In order to analyze controller induced performance both an error and a charge in error of the system output an chosen as fuzzy variables. The fuzzy logic jot a sensor induced performance uses two variables : a deviation between two sensor outputs and its frequency, Fuzzy weighting modulator generates an output signal compensated for faulty input signal. Simulations show that the : proposed fault tolerant control scheme jot a steam generator regulates welt water level by suppressing fault effect of either controllers or sensors. Therefore through duplicating sensors and controllers with the proposed fault tolerant scheme, both a reliability of a steam generator control and sensor system and that of a power plant increase even mote.

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A New Control of Three-Phase PWM Rectifier with Single Current Sensor (단일 전류 센서를 사용한 3상 PWM 정류기의 새로운 제어)

  • Lee, U-Cheol;Hyeon, Dong-Seok;Lee, Taek-Gi
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.48 no.8
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    • pp.440-447
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    • 1999
  • This paper proposes a control method for three-phase PWM rectifier with only single current sensor in DC link side. A PWM modulation strategy for reconstructing three phase currents from the DC link current is given. The states of the retifier switch are modified so that all phase currents can be reconstructed in a switching period although one or two of active vectors is applied only for a short time. Therefore, a new current control using an adjustment scheme of the modulation signal for three-phase PWM rectifier will be discussed, and verified the experimental results.

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Efficient Interference Control Technology for Vehicular Moving Networks

  • Oh, Sung-Min;Lee, Changhee;Lee, Jeong-Hwan;Park, Ae-Soon;Shin, Jae Sheung
    • ETRI Journal
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    • v.37 no.5
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    • pp.867-876
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    • 2015
  • This paper proposes an efficient interference control scheme for vehicular moving networks. The features of the proposed scheme are as follows: radio resources are separated into two resource groups to avoid interference between the cellular and vehicle-to-vehicle (V2V) links; V2V links are able to share the same radio resources for an improvement in the resource efficiency; and vehicles can adaptively adjust their transmission power according to the interference among the V2V links (based on the distributed power control (DPC) scheme derived using the network utility maximization method). The DPC scheme, which is the main feature of the proposed scheme, can improve both the reliability and data rate of a V2V link. Simulation results show that the DPC scheme improves the average signal-to-interference-plus-noise ratio of V2V links by more than 4 dB, and the sum data rate of the V2V links by 15% and 137% compared with conventional schemes.

A Study on Rate-Based Congestion Control Using EWMA for Multicast Services in IP Based Networks (IP 기반 통신망의 멀티캐스팅 서비스를 위한 지수이동 가중평판을 이용한 전송률기반 폭주제어에 관한 연구)

  • Choi, Jae-Ha;Lee, Seng-Hyup;Chu, Hyung-Suk;An, Chong-Koo;Shin, Soung-Wook
    • Journal of the Institute of Convergence Signal Processing
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    • v.8 no.1
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    • pp.39-43
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    • 2007
  • In high speed communication networks, the determination of a transmission rate is critical for the stability of a closed-loop network system with the congestion control scheme. In ATM networks, the available bit rate (ABR) service is based on a feedback mechanism, i.e., the network status is transferred to the ABR source by a resource management (RM) cell. RM cells contain the traffic information of the downstream nodes for the traffic rate control. However, the traffic status of the downstream nodes can not be directly transferred to the source node in the IP based networks. In this paper, a new rate-based congestion control scheme using an exponential weighted moving average algorithm is proposed to build an efficient feedback control law for congestion avoidance in high speed communication networks. The proposed congestion control scheme assures the stability of switch buffers and higher link utilization of the network. Moreover, we note that the proposed congestion scheme can flexibly work along with the increasing number of input sources in the network, which results in an improved scalability.

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RBFNN Based Decentralized Adaptive Tracking Control Using PSO for an Uncertain Electrically Driven Robot System with Input Saturation (입력 포화를 가지는 불확실한 전기 구동 로봇 시스템에 대해 PSO를 이용한 RBFNN 기반 분산 적응 추종 제어)

  • Shin, Jin-Ho;Han, Dae-Hyun
    • Journal of the Institute of Convergence Signal Processing
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    • v.19 no.2
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    • pp.77-88
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    • 2018
  • This paper proposes a RBFNN(Radial Basis Function Neural Network) based decentralized adaptive tracking control scheme using PSO(Particle Swarm Optimization) for an uncertain electrically driven robot system with input saturation. Practically, the magnitudes of input voltage and current signals are limited due to the saturation of actuators in robot systems. The proposed controller overcomes this input saturation and does not require any robot link and actuator model parameters. The fitness function used in the presented PSO scheme is expressed as a multi-objective function including the magnitudes of voltages and currents as well as the tracking errors. Using a PSO scheme, the control gains and the number of the RBFs are tuned automatically and thus the performance of the control system is improved. The stability of the total control system is guaranteed by the Lyapunov stability analysis. The validity and robustness of the proposed control scheme are verified through simulation results.

Precise Tracking Control of Parallel Robot using Artificial Neural Network (인공신경망을 이용한 병렬로봇의 정밀한 추적제어)

  • Song, Nak-Yun;Cho, Whang
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.1 s.94
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    • pp.200-209
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    • 1999
  • This paper presents a precise tracking control scheme for the proposed parallel robot using artificial neural network. This control scheme is composed of three feedback controllers and one feedforward controller. Conventional PD controller and artificial neural network are used as feedback and feedforward controller respectively. A backpropagation learning strategy is applied to the training of artificial neural network, and PD controller outputs are used as target outputs. The PD controllers are designed at the robot dynamics based on inter-relationship between active joints and moving platform. Feedback controllers insure the total stability of system, and feedforward controller generates the control signal for trajectory tracking. The precise tracking performance of proposed control scheme is proved by computer simulation.

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Control Scheme of Emergency Power Supply for Elevator Emergency Call System (승강기의 비상 통화장치용 비상 전원장치의 충·방전 제어회로)

  • Park, Noh-Sik;Lee, Dong-Hee
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.8
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    • pp.40-48
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    • 2015
  • In this paper, battery charging and discharging circuit with a single voltage power supply is proposed. The proposed circuit has the separated current path and charging-monitoring sequence control scheme. In the charging sequence, the proposed 2-level comparator combined with control signal of the micro-processor can control the constant charging current to protect the over current of the battery. Furthermore, the proposed circuit uses a periodic main power switch control to detect the discharging characteristics to estimate the approximated battery life-time. In the experiments, the proposed emergency power supply for emergency call system has 89% efficiency with 98% power factor. And the proposed sequence control scheme is well operated in the designed emergency power system.

Design of a DSP-Based Adaptive Controller for Real Time Dynamic Control of AM1 Robot

  • S. H. Han;K. S. Yoon;Lee, M. H.;Kim, S. K.
    • 제어로봇시스템학회:학술대회논문집
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    • 1998.10a
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    • pp.100-104
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    • 1998
  • This paper describes the real-time implementation of an adaptive controller fur the robotic manipulator. Digital signal processors(DSPs) are special purpose micro-processors that are particularly powerful for intensive numerical computations involving sums and products of variables. TMS320C50 chips are used in implementing real time adaptive control algorithms to provide an enhanced motion for robotic manipulators. In the proposed scheme, adaptation laws are derived from the improved Lyapunov second stability analysis based on the direct adaptive control theory. The adaptive controller consists of an adaptive feedforward controller and feedback controller. The proposed control scheme is simple in structure, fast in computation, and suitable for real-time control. Moreover, this scheme does not require any accurate dynamic modeling, nor values of manipulator parameters and payload. Performance of the adaptive controller is illustrated by simulation and experimental results for a assembling robot.

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Spectrum Reuse with Power Control for Two-Tier Femtocell Networks

  • Kim, Youngju;Wang, Hano;Hong, Daesik
    • IEIE Transactions on Smart Processing and Computing
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    • v.3 no.5
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    • pp.275-284
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    • 2014
  • This paper considers two-tier networks consisting of macrocells and femtocells operating in the same spectrum. This paper proposes a femtocell spectrum reuse scheme that determines the shared spectrum and transmit power for the femtocells to mitigate the effects of cross-tier interference between the macrocells and femtocells. The proposed scheme provides macrocell throughput that is unaffected by the increasing number of femtocells per cell site and improves the femtocell signal quality at the same time by limiting the cross-tier interference. This study analyzed the per-tier signal-to-interference ratio (SIR) and outage probability of the proposed scheme to investigate the macrocell and femtocell performance. The total throughput of the proposed scheme was analyzed based on the outage probabilities. The analysis and numerical results proved that high femtocell throughput can be achieved using only a small fraction of the spectrum while protecting the macrocell throughput. As a result, an improved total throughput was achieved enforcing higher spatial reuse.