최적화 기법을 적용한 매체 이송 시스템의 이송속도 및 비틀어짐 제어기의 이득값 결정

차호영(Ho-Young Cha),범선호(Sun-Ho Bum),김민수(Min-Soo Kim),이순걸(Soon-Geul Lee) 대한기계학회 2009 大韓機械學會論文集A Vol.33 No.6

In this paper, we made a simple paper feeding system which is one of MTS (media transport system) and controllers. The plant has a flexible paper and two driving rollers and two driven rollers. The control system has two conventional PID controllers. Skew angle and feeding speed of MTS deteriorate the quality of feeding system. In order to control a feeding speed and skew of feeding paper, we control rotational velocity of two driving rollers. Therefore, this controller has two inputs and two outputs as MIMO (multi-input and multi-output) system. The control inputs were the feeding speed and the skew displacement of the paper. The control outputs were the rotational velocity to each driving roller. To find appropriate PID gains of two controllers, we proposed an optimization technique. We assume the system variables and performance of a whole system as follows. PID gains of two controllers for skew and feeding speed are system variables. System performance is both skew and feeding speed. We simulates to making mathematical correlation using global Kriging interpolation. To find appropriate value of system variables, optimization method is simulation in sequence as following method. First, the optimization solver simulates with DOE (design of experiment) tables to find correlation equation of both system variable and performances. Then, the solver guesses the appropriate values and simulates if the system variables are appropriate or not. If the result of validation doesn’t satisfy the convergence and iteration tolerance, the solver makes a new Kriging models and iterates this sequence until satisfy the tolerances.

Linear Motor 이송계의 진동 최소화를 위한 이송속도 최적화

최영휴,홍진현,최응영,김태형,최원선 한국공작기계학회 2004 한국공작기계학회 추계학술대회논문집 Vol.2004 No.-

Linear motor feed drive systems have been broadly used in machine tools or precision automatic feed systems. Recently, modern machine tools require high speed and high precision feed drive system to achieve high productivity. Unfortunately, a feed drive system, even though it was optimum designed, may experience severe transient vibrations during high-speed operation if its feed rate control is unsuitable. A rough feed rate curve having discontinuity in its acceleration profile causes a serious vibration problem in the feed slides system. This paper presents a feed rate optimization of a machine tool feed slide system, which is driven by a linear motor, for its minimum vibrations. Firstly, a 4-degree-of-freedom lumped parameter model is proposed for the vibration analysis of a linear motor driven machine tool feed drive system. Next, a feed rate optimization of the feed slide is carried out for minimum vibrations. The feed rate curve optimization strategy is to find out the most appropriate acceleration profile with jerk continuity. Of course, the optimized feed rate should approximate to the desired one as possible. A genetic algorithm with variable penalty function was used in this feed rate optimization.

고속이송계의 열변형오차 자동보정에 관한 연구

고해주(Hai-Ju Ko),정윤교(Yoon-Gyo Jung) 한국기계가공학회 2007 한국기계가공학회지 Vol.6 No.4

In the recent years, development of machine tool with high speed feeding system have brought a rapid increase in productivity. Practically, thermal deformation problem due to high speed is, however, become a large obstacle to realize high precision machining. In this study, therefore, the construction of automatic error compensation system to control thermal deformation in high speed feeding system with real time is proposed. To attain this purpose, high speed feeding system with feeding speed 60㎜/min is developed and experimental equation for relationship between thermal deformation and temperature of ball screw shaft using multiple regression analysis is established. Furthermore, in order to analyze thermal deformation error, compensation coefficient is determined and thermal deformation experiments is carried out. From obtained results, it is confirmed that automatic error compensation system constructed in this study is able to control thermal deformation error within 15~20 ㎛.

병렬기구 공작기계의 이송오차 측정에 관한 연구

고해주(Hai-Ju Ko),황종대(Joung-Dae Hwang),정윤교(Yoon-Gyo Jung),김재실(Chae-sil Kim) 한국기계가공학회 2008 한국기계가공학회 춘추계학술대회 논문집 Vol.2008 No.-

The improvement of the productivity and quality of products were caused by adaptation of machine tool in the industry. Also, it is connected with development of products with multi function and high price, so it leads to industrial growth in the field of machine tool. For high speed of the machine tool, the feeding system is an important function, and technical advance of this feeding system is derived the development of 5 axis machine tool mounted high and multi axis feeding system. Moreover, PKMT(Parallel Kinematic Machine Tool) using robot technology with 5 axis function is developed, and it is becoming the advanced machine tool which space motion is very convenient. But low motion accuracy by multi axis movement in PKMT is a serious problem. So, the development of measurement system for the evaluation of motion accuracy is required. In this study, we are purpose to propose the measurement method about the high speed and multi axis feeding system of machine tool, and to obtain reliability for measuring result.

페룰 가공용 초정밀 무심 연삭기의 유정압 이송계에 대한 고강성화 특성 해석

김석일(Seok-Il Kim) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11

In this study, in order to realize a high-precision centerless grinding machine for machining ferrules with sub-micron order, the structural characteristic analysis and evaluation are performed on the high-precision feeding system consisted of steel bed, hydrostatic guide way and ballscrew feeding mechanism. The previous study related to the first prototype of high-precision feeding system showed that the deformation of ballscrew support-bearing brackets is the main cause of reduction in the axial stiffness of feeding system, and the deflection of bed structure and the bending deformation of hydrostatic guide rails are the main causes of reduction in the vertical stiffness of feeding system. Therefore the second prototype of high-precision feeding system is designed focused on the improvement of the structural stiffnesses of bed, hydrostatic guide rails, ballscrew and ballscrew support-bearing brackets. And the simulated results illustrate that the second prototype has the axial and vertical stiffnesses necessary to realize the high-precision centerless grinding machine.

고속 HMC 이송계의 운동특성 평가 및 운동오차 예측

최헌종,허남환,강은구,이석우,홍원표 한국공작기계학회 2004 한국공작기계학회 추계학술대회논문집 Vol.2004 No.-

Recently, the evolution in production techniques (e.g. high-speed milling) and the complex shapes involved in modern production design has been increasingly popular. The key to the achievement is a drastic improvement of the dynamic behavior of the machine tool axes used in production machinery. The more complex these tool paths the higher the speed and acceleration requirements. But it is very difficult to reach the target for high speed machine tool because of the limitations of servo system and motion control system. However the direct drive design of machine tool axes, which is based on linear motors and which recently appeared on the market, is a viable candidate to meet the ever increasing demands, because of these advantages such as no backlash, less friction, more mechanical simplicity and very higher acceleration and velocity comparing to the traditional system. This paper focused on the performance tests of the high speed horizontal machine tool based on linear motor. Especially, dynamic characteristics were investigated through circular test and circular form machining test is carried out considering many important parameter. Therefore these several experiments is used to be evaluated the model for prediction of circular motion error and circular machined error.

정밀나사 비전검사시스템용 자동공급장치 진동특성의 해석

서예린(Ye-Rin Seo),박근(Keun Park),김성걸(Seong-Keol Kim),나승우(Seung-Wu Ra) 한국생산제조학회 2011 한국생산제조학회지 Vol.20 No.4

Recent trends for the miniaturization and weight reduction of portable electronic parts have driven uses of subminiature components. Assembly of the miniaturized components requires subminiature screws of which pitch sizes are micrometer scale. To produce such subminiature screws with high precision threads, not only a precision forming technology but also a high-precision measurement technology is required. The present study covers the development of a vision inspection system for precision screws for the automatic measurement of subminiature screws with high speed and reliability. In this study, the feeding unit that transfers the subminiature screws to the inspection unit is investigated through finite element(FE) analysis. The vibration characteristics of the feeding unit are predicted through FE analyses, from which we can determine whether the subminiature screw can be stably fed into the inspection unit or not. The effects of several design parameters on the vibration characteristics are also discussed.

AE 및 가속도 신호를 이용한 리니어 모터 이송시스템의 특성분석

유송민 한국공작기계학회 2000 한국공작기계학회 추계학술대회논문집 Vol.2000 No.-

A brushless linear motor is suitable for operation with higher speed and precision. Since it does not involve mechanical coupling, linear driving force can be applied directly. Conventional PID and fuzzy controllers are implemented and performance results using those controllers are compared. Along with better simulated performance observed using fuzzy controller, further fabrication is to be included with various empirical results. Several system operational characteristics have been observed. Typical nonlinearities as friction, cogging and torque or thrust ripple that might deteriorate system performance would be tackled using presumably effective method such as neural network based learning controller.

복합공작기계의 이송계 운동정밀도 측정의 연구

고해주(Hai-Ju Ko),정윤교(Yoon-Gyo Jung) 한국기계가공학회 2007 한국기계가공학회지 Vol.6 No.3

Recently, the machine tools called multi-task machines, which mounted rotary axes on the table or spindle are used increasingly. Accordingly, multi-task machine tool takes a growing interest on the motion accuracy of feed drive system. In this study, measurement and diagnosis of motion errors ware attempted from circular pattern obtained by using DBB (Double ball bar) device. Those were obtained at both clockwise and counter clockwise motions in mutually perpendicularly intersecting three planes. The reliability of error measurement system for multi-task machine tool was verified by the direct test cutting.

정밀공작기계용 이송시스템의 성능평가 사례

박천홍(Chun Hong Park),황주호(Joo Ho Hwang) Korean Society for Precision Engineering 2004 한국정밀공학회지 Vol.21 No.8