• Title, Summary, Keyword: Machine Control

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Input Shaping for Servo Control of Machine Tools (공작기계의 서보제어와 입력성형기법)

  • Kim, Byung-Sub
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.9
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    • pp.1011-1017
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    • 2011
  • Servo control loops are a core part in the control architecture of machine tools. Servo control loops manage acceleration, velocity and position of all the axes in a machine tool based on commands. The performance of servo control loops sets the basis for quality of production paris and cycle time reduction. First, this paper presents a general control architecture of machine tools and several control schemes in literature, which can be applicable to machine tools control; including Zero Phase Error Tracking Control (ZPETC) and Cross Coupling Control (CCC). After that, modem control strategies to mitigate the problem of high speed machining are reviewed. In high speed machining, high accelerations excite the machine structure up to high frequencies, thereby exciting the structure's modes of vibration. These structural vibrations need to be damped if accurate positioning or trajectory following is required. Input shaping is an attractive option in dealing with structural vibrations. The advantages and drawbacks of using input shaping technique for machine tools are discussed in detail.

High-Precision Control of Magnetic Levitation System

  • Jeon, Jeong-Woo;Caraiani, Mitica;Lee, Ki-Chang;Hwang, Don-Ha;Lee, Joo-Hoon;Kim, Yong-Joo;Nam, Taek-Kun;Kim, Sung-Shin
    • 제어로봇시스템학회:학술대회논문집
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    • pp.2575-2580
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    • 2005
  • In this paper, we address two position control scheme; the lead-lag control and the sliding mode control for a stage system, which is levitated and driven by electric magnetic actuators. This consists of a levitating object (called platen) with 4 permanent magnetic linear synchronous motors in parallel. Each motor generates vertical force for suspension against gravity and propulsion force horizontally as well. This stage can generate six degrees of freedom motion by the vertical and horizontal forces. Dynamic equations of the stage system are derived simply. The sliding mode control algorithm is more effective than the lead-lag control algorithm to reduce effects from movements and disturbances of other axis.

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Modern Probabilistic Machine Learning and Control Methods for Portfolio Optimization

  • Park, Jooyoung;Lim, Jungdong;Lee, Wonbu;Ji, Seunghyun;Sung, Keehoon;Park, Kyungwook
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.14 no.2
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    • pp.73-83
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    • 2014
  • Many recent theoretical developments in the field of machine learning and control have rapidly expanded its relevance to a wide variety of applications. In particular, a variety of portfolio optimization problems have recently been considered as a promising application domain for machine learning and control methods. In highly uncertain and stochastic environments, portfolio optimization can be formulated as optimal decision-making problems, and for these types of problems, approaches based on probabilistic machine learning and control methods are particularly pertinent. In this paper, we consider probabilistic machine learning and control based solutions to a couple of portfolio optimization problems. Simulation results show that these solutions work well when applied to real financial market data.

Fault Detection and Diagnosis based on Fuzzy Algorithm in the Injection Molding Machine Barrel Temperature (사출 성형기 Barrel 온도에 관한 퍼지알고리즘 기반의 고장 검출 및 진단)

  • 김훈모
    • Journal of Institute of Control, Robotics and Systems
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    • v.9 no.11
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    • pp.958-962
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    • 2003
  • We acquired data of injection molding machine in operation and stored the data in database. We acquired the data of injection molding machine for fault detection and diagnosis (FDD) continuously and estimated the fault results with a fuzzy algorithm. Many of FDD are applied to a huge system, nuclear power plant and a computer numerical control(CNC) machine for processing machinery. But, the research of FDD is rare in injection molding machine compare with computer numerical control machine. We appraise the accuracy of the FDD and the limit of the application to the injection molding machine. We construct the fault detection and diagnosis system based on fuzzy algorithm in the injection molding machine. Data of operating injection molding machine are acquired in order to improve the reliability of detection and diagnosis.

Stability Enhancement of Four-in-Wheel Motor-Driven Electric Vehicles Using an Electric Differential System

  • Hartani, Kada;Merah, Abdelkader;Draou, Azeddine
    • Journal of Power Electronics
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    • v.15 no.5
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    • pp.1244-1255
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    • 2015
  • This paper presents a new multi-machine robust control based on an electric differential system for electric vehicle (EV) applications which is composed of four in-wheel permanent magnet synchronous motors. It is based on a new master-slave direct torque control (DTC) algorithm, which is used for the control of bi-machine traction systems based on a speed model reference adaptive system observer. The use of an electric differential in the design of a new EV constitutes a technological breakthrough. A classical system with a multi-inverter and a multi-machine comprises a three-phase inverter for each machine to be controlled. Another approach consists of only one three-phase inverter for several permanent magnet synchronous machines. The control of multi-machine single-inverter systems is the subject of this study. Several methods have been proposed for the control of multi-machine single-inverter systems. In this study, a new master-slave based DTC strategy is developed to generate an electric differential system. The entire system is simulated by Matlab/Simulink. The simulation results show the effectiveness of the new multi-machine robust control based on an electric differential system for use in EV applications.

Corrective Control of Input/Output Asynchronous Sequential Machines for Overcoming Disturbance Inputs (외란 입력을 극복하기 위한 입력/출력 비동기 머신의 교정 제어)

  • Yang, Jung-Min;Kwak, Seong-Woo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.3
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    • pp.591-597
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    • 2009
  • The problem of controlling a finite-state asynchronous sequential machine is examined. The considered machine is governed by input/output control, where access to the state of the machine is not available. In particular, disturbance inputs can infiltrate into the asynchronous machine and provoke unauthorized state transitions. The control objective is to use output feedback to compensate the machine so that the closed-loop system drive the faulty asynchronous machine from a failed state to the original one. Necessary and sufficient condition for the existence of appropriate controllers are presented in a theoretical framework. As a case study, the closed-loop system of an asynchronous machine with the proposed control scheme is implemented in VHDL code.

A Study on Kinematic Analysis of Feeding Control Mechanism of a Lock Stitch Sewing Machine (본봉용 재봉기의 이송조절기구의 기구 해석에 관한 연구)

  • 신대영;전경진;송창섭
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.12
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    • pp.48-54
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    • 1998
  • In sewing, fabrics is fed by an elliptic motion of the feed dog. The feeding control mechanism controls an elliptic motion of the feed dog, finally, controls stitch spacings and feeding directions of fabrics. This study discusses the feeding control mechanism of an industrial lock stitch sewing machine, which is a good example to study a machine kinematics. This study makes mathematical expressions of machine's motion in the feeding control mechanism. Thus, the motions of this mechanism are characterized, which will be used for kinematic analysis of the feed dog later. Also, the above mathematical expressions may be a basis for the new design of the feeding control mechanism and may be applied to development of the similar feeding control mechanism of other type sewing machine.

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Design of Hydraulic Control Systems for a Disc Spinning Machine

  • Park, Geun-Seok;Lim, Jun-Young;Kang, E-Sok;Kang, Jung-Sik
    • 제어로봇시스템학회:학술대회논문집
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    • pp.115.4-115
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    • 2002
  • The disc spinning machine is a specific production machine for discs of automobile. Using this machine, we could product superior wheels in hardness and strength to the press method and the machine made process time shorten by one-pass spinning. But, the spinning machine became huge because it needed maximum pressure during the process and this can badly affect the lifetime of components. In this paper, hydraulic control system was designed to make up for defects of spinning machine and to shorten overusing power. Experimental hydraulic control system was used to simulate the wheel disc spinning process and the control performance was evaluated for the required forces and positions.

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Reliability Prediction of Touch-Machine Control Panel Using MIL-HDBK-217F and Telcordia SR-332 : Case Study (MIL-HDBK-217F와 Telcordia SR-332를 이용한 Touch-Machine Control Panel의 신뢰도 예측 사례 연구)

  • Lee, Guk Jin;Kim, Sang Boo;Park, Woo Jae;Oh, Keuk Ki;Park, Jin Whan;Lee, Dong Geon
    • Journal of the Korea Society of Systems Engineering
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    • v.12 no.2
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    • pp.9-18
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    • 2016
  • Machine switch type control panel is widely used for machine tools in Korea. They, however, have some difficulties in identifying the current operating status of machine tools especially when exposed to cutting oil. And also they have quality problems of operating failures. A new capacitor touch type machine control panel is developed and its reliability is predicted. MIL-HDBK-217F and Teclordia SR-332 are used for its reliability prediction and the prediction results are compared.

Tension Control of a Winding Machine using Time-delay Estimation (시간 지연 추정 기법을 이용한 권취기의 장력 제어 알고리즘)

  • Heo, Jeong-Heon;You, Byungyong;Kim, Jinwook
    • Journal of Drive and Control
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    • v.15 no.3
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    • pp.21-28
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    • 2018
  • We propose a tension controller based on a time-delay estimation (TDE) technique for a winding machine. Firstly, we perform the necessary calculations to derive a mathematical model of the winding machine. In this sense, it is revealed that the roll radius of the winding machine is characteristically seen to be increasing or decreasing during the winding process. That being said, it is noted that the parameters of the winding machine are coupled and constantly changing during this process. Understandably then, it is noted that the model is shown to be nonlinear and time-varying. Secondly, we propose the way to apply the TDE based controller which is the so-called Time-delay Control (TDC). The TDC utilizes the time-delayed information intentionally to compensate the nonlinear and time-varying characteristics. As we have seen, the proposed controller consists of two parts: one is a TDE component, and the other is an error dynamics component which is defined by a user. In a computer simulation based on the Matlab/Simulink program, the proposed controller is compared with a conventional PID controller, which is widely used in the tension control of the winding machine. The proposed controller reduces the incidence of overshoot and steady-state error in the tension control, as compared to the conventional PID controller.