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5-Head Router Machine 구조물의 진동최소화를 위한 동적설계 최적화
최영휴(Young-Hyu Choi),장성현(Sung-Hyun Jang),최응영(Eung-Young Choi),하종식(Jong-Sik Ha),조용주(Yong-Ju Cho) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5
This paper presents a multi-step design optimization for 5-head router machine using a genetic algorithm. The design problem is to find out the optimum configuration and thickness of structural members which minimize vibrations, the static compliance, dynamic compliance and weights of the machine structure simultaneously under several constraints such as dimensional constraints, maximum deflection limit, safety criterion and maximum vibration amplitude limit. Optimization results showed a great reduction in compliance and vibration amplitude at the spindle nose of the router machine without increase of machine weight.
라우터머신용 랙 피니언 방식 이송시스템의 / 진동해석 및 동적설계 최적화
최영휴(Young-Hyu Choi),최응영(Eung-Young Choi),장성현(Sung-Hyun Jang),하종식(Jong-Sik Ha),조용주(Yong-Ju Cho) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5
In order to prevent a router machine feed drive system from transient operational vibration, this paper presents vibration analysis and dynamic design optimization of a rack and pinion typed feed drive system for a router machine. The feed drive system was mathematically idealized as a 5-degree-of-freedom lumped parameter model. Stiffness parameters of motor-shaft, rack and pinion gears, and machine structure were appropriately considered in the modeling. Computational experiment was carried out to obtain vibrations of the feed drive system during its transient speed operation. Furthermore, optimum design parameters were successfully obtained by using a Genetic Algorithm based design optimization method.
항공기 기체 가공용 5-Head Router Machine 구조물의 경량ㆍ고강성화 최적설계
최영휴(Young-Hyu Choi),차상민(Sang-Min Cha),하종식(Jong-Sick Ha),조용주(Yong-Ju Cho) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11
In this paper, a multi-step optimization using a G.A.(Genetic Algorithm) with variable penalty function is introduced to the structural design optimization of a 5-head route machine. In the first stage of the design optimization, cross-section shapes of the structural members are optimized. The following two stages are static and dynamic design optimization stages. In the static optimization stage, the static compliance and weight of the structure are minimized simultaneously under some dimensional constraints and deflection limits. On the other hand, the dynamic compliance and the weight of the machine structure are minimized simultaneously in the dynamic design optimization stage. The proposed design optimization method was successfully applied to the 5-head router machine design optimization. As the results, static and dynamic compliances of the 5-heas router machine have decreased by 5.3% and 43.6% respectively compared with the initial design, while the weight of the structure also has decreased by 6.6%..
이창조(Chang-Jo Lee),장성현(Sung Hyun Jang),정우영(Woo-Young Jung),김성수(Sung-Soo Kim),최용규(Yong-Gyu Choi),최영휴(Young-Hyu Choi) 한국생산제조학회 2009 한국공작기계학회 추계학술대회논문집 Vol.2009 No.-
PHC (pretentioned spun high strength concrete) pile is widely used in construction site for foundation works as an essential step of work process to increase bearing capacity. But the several construction methods to hammer pile in the ground caused vibration and noise to generate. However, PHC screw pile which has the half circle type thread of screw is the noiseless and vibrationless pile because of inserting it into the ground by rotation of auger. The shear stresses or maximum stress for pile were occurred by pressure of soil layer during the constructing a PHC screw pile. So, we carried out theoretical calculation and FE analysis to calculate safety factor of PHC screw pile.
정용민,장성현,황현영,최영휴,하종식 한국공작기계학회 2008 한국공작기계학회 추계학술대회논문집 Vol.2008 No.-
This paper describes a structural design. optimization for light weight and minimum compliance using G.A. and a study on dynamic stiffness evaluation of a 5-axes multi-tasking machine tool. Dynamic stiffness is one of important factors regarding to machine tool accuracy. In design optimization, we optimized the thickness of structural member which minimize the compliance and weight of the machine structure under several constraints. Furthermore, dynamic stiffness, in this study, were obtained by using both FEM analysis and an experimental dynamic stiffness test, that is a random excitation test by using a hydraulic exciter. Both the theoretical and experiment analysis results showed good agreement with each other. Finally, some discussion and review from the view point absolute dynamic stiffness were made based on the analysis results.
평면 2자유도 모델을 이용한 리니어 모터로 구동되는 다축 마이크로 밀링머신 크로스헤드의 진동해석
장성현,황현영,정용민,최영휴,홍정표 한국공작기계학회 2008 한국공작기계학회 추계학술대회논문집 Vol.2008 No.-
In this paper, a simple 2-D.O.F. planar motion model is proposed in order to analyze the snake motion of a cross head assembly of a Multi-axis micro milling machine (M4) for BT-factory, that is travelling on linear guide. In the proposed mathematical model, the friction between head and guide ways is neglected, and also the support structures including the linear guides of M4 are assumed to be rigid. The equations of motion of the proposed model are derived and successfully solved to determine vibration responses of a cross head assembly due to some applied traction forces.
이산화된 탐색공간에서 다구찌 방법을 이용한 구조 최적설계에 관한 연구
장성현,정우영,정용민,권봉철,최영휴 한국공작기계학회 2008 한국공작기계학회 추계학술대회논문집 Vol.2008 No.-
Nowadays, there are several design problem having discrete variables in the industrial fields. The researchers are using the optimization method, such as genetic algorithm (GA), simulated annealing (SA), design of experiment (DOE) and taguchi method (TM), to solve it's design problem. Moreover, people want to decrease the computational cost and time. Therefore, in this paper, we proposed the iterative optimization algorithm which repetitively searched a local region to find best solution in discrete searching space using TM. The optimal solution in each local region is obtained by S/N ratio for the evaluation function that consists of the objective function and penalty function. Also, we have applied our algorithm to 3-bar, 10-bar, and 25-bar truss optimization problem.
장성현,정용민,황현영,최영휴,박종권 한국공작기계학회 2008 한국공작기계학회 춘계학술대회논문집 Vol.2008 No.-
During a decade, there are many researches on microfactory which is the miniature, flexible, and efficient manufacturing system for the micro/meso scale machining device. Moreover many micro machine tool has developed in Japan, U.S., Europe, and Korea. Already we developed a 3-axis micro milling machine with 300×200×320 ㎣ machine size for microfactory. In this study, we introduce the design of a high speed spindle system with air bearings for our micro milling machine. Desired operation speed range of the spindle system is 100,000 ~ 150,000 rpm. In. design step, we have consideration for minimum critical speed, compliance, and weight construction of the spindle system. The shaft length, the shaft outer diameter, bearing positions and bearing stiffness were set as the design values. After the final design of spindle model, we carried out dynamic analysis a spindle system for a micro milling machine by using ADROS, which is our own developed S/W for dynamic design analysis of rotor systems. As the result, we designed a spindle system having the critical speed above the operating speed.