• 한국정밀공학회지
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• 제17권2호
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• pp.185-192
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• 2000

Cam mechanism is one of the common devices used in many automatic machinery. Since the motion of the cam mechanism depends on the shape of the cam and the type of the follower, the shape design procedure must be well defined in order to determine the accurate shape of the cam corresponding to the prescribed motion of the follower. This paper proposes a new approach for designing the shape of disk cams. The proposed relative velocity method uses the relative velocity at center of the follower roller or at contact point between the cam and the follower for 4 different types of the disk cam systems. Also, the relative velocity method for determining the cam profile uses the geometric relationships of the cam and the follower.

• 한국정밀공학회지
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• 제20권1호
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• pp.222-228
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• 2003

A reliable tool wear monitoring technique is the one of important aspects for achieving an integrated and self-adjusting manufacturing system. In this paper, a tool wear estimation approach for turning is proposed. This approach uses the model of cutting force, spindle displacement and their relation. A series of experiments were conducted by designing experimental techniques to determine the relationship between flank wear and cutting force coefficient as well as cutting parameters such as cutting speed, depth of cut and feed. The proposed model performance has shown that the spindle displacement model predicts tool wear with high accuracy and spindle displacement signal is possible to replace cutting force signal.

• 한국정밀공학회지
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• 제18권4호
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• pp.197-202
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• 2001

This paper proposes a design method for improving the disassembly by using the axiomatic approach. A product developer must design disassembly as well as assembly when designing the structure of a product. Axiomatic approach is a design tool that optimizes design. In this paper design evaluation method using information axiom sets impact variables and value function. As a result, examining the relationship between the functional requirements and evaluating the information can optimize designs.

• International Journal of Precision Engineering and Manufacturing
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• 제3권4호
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• pp.54-63
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• 2002

In recent years, mechanical systems such as high speed vehicles and railway trains moving on elastic beam structures have become a very important issue to consider. In this paper, a general approach, which can predict the dynamic behavior of a constrained mechanical system moving on a flexible beam structure, is proposed. Various supporting conditions for the foundation support are considered for the elastic beam structure. The elastic structure is assumed to be a non-uniform and linear Bernoulli-Euler beam with a proportional damping effect. Combined differential-algebraic equation of motion is derived using the multi-body dynamics theory and the finite element method. The proposed equations of motion can be solved numerically using the generalized coordinate partitioning method and predictor-corrector algorithm, which is an implicit multi-step integration method.

• International Journal of Precision Engineering and Manufacturing
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• 제3권4호
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• pp.64-71
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• 2002

Recently, mechanical systems such as a high-speed vehicles and railway trains moving on flexible beam structures have become a very important issue to consider. Using the general approach proposed in the first part of this paper, it is possible to predict motion of the constrained mechanical system and the elastic structure, with various kinds of foundation supporting conditions. Combined differential-algebraic equation of motion derived from both multibody dynamics theory and finite element method can be analyzed numerically using a generalized coordinate partitioning algorithm. To verify the validity of this approach, results from the simply supported elastic beam subjected to a moving load are compared with the exact solution from a reference. Finally, parametric study is conducted for a moving vehicle model on a simply supported 3-span bridge.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1993년도 춘계학술대회 논문집
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• pp.375-379
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• 1993

공정계획(process planning)이란 제품에 대한 설계정보 및 제한된 가용자원에 대한 정보를 바탕으로 비용, 생산량을 고려하여 원자재를 원하는 형태로 변형시키기 위한 방법의 체계적인 결정과정이라 할 수 있으며, 생산계획(production planning: scheduling)이나 작업계획(operation planning)과 연계하여 설계와 생산을 연결하는 교량 역할을 수행한다. 이러한 공정계획 작업을 컴퓨터에 의해 자동화하기 위한 컴퓨터 원용 공정계획(computer aided process planning : CAPP)은 변환적 방식(variant approach)에서 시작되어 창생적 방식(generative approach)으로 발전되어 왔으며 인공지능 기법을 응용 한 지식기반 CAPP(knowledge based CAPP) 방식에 이르기 까지 CAM-1's CAPP, APPAS, GARE, SIPS, XCUT등 수많은 연구가 행해 졌다. 본 연구에서는 자동차 부품 업체인 K사의 공정계획 사례를 바탕으로 범용성이 있는 개방형 공정계획 시스템의 개발을 목표로 한다. 본 시스템에서 i) 설계정보는 객체지향에 의해 표현된 형상특징을 사용하고 ii) 공정계획은 국부적 공정계 획과 전체적 공정계획 과정(golbal planning)으로 구별하였고 iii) 공정계획을 위한 정보는 지식 베이스(knowledge base : KB) 와 데이타 베이스(data base : DB)로 구분하였다. 또한 iv) 정보의 모듈화를 통하여 임의의 제조라인에 적합하도록 개방형을 추구하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.628-634
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• 1995

In the area of assembly process of micro-chips and electronic parts on the printed circuit board, surface mounting device(SMD) is used as a fundamental tool. Generally speaking, the motion of the SMD is based on the ball screw system operated by any type of actuators. The ball screw system is a mechanical transformer which converts the mechanical rotational motion to the translational one. Also, this system could be considered as an efficient motion device against mechanical backash and friction. Therefore a dynamic modeling and stste sensitivity analysis of the ball screw system in SMD have to be done in the initial design stage. In this paper, a simple mathematical dynamic model for this system and the sensitivity snalysis are mentioned. Especially, the bond graph approach is used for graphical modeling of the dynamic system before analysis stage. And the direct differentiation method is used for the state sensitivity analysis of the system. Finally, some trends for the state variables with respect to the design variables could be suggested for the better design based on the results on the results of dynamic and state sensitivity.

• 한국정밀공학회지
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• 제24권11호
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• pp.134-143
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• 2007

A new approach based on mean value coordinate combined with Laplacian coordinate is proposed for shape deformation of a large polygon model composed of triangular net. In the method, the spherical mean value coordinates for closed control meshes is introduced to describe a vertex in the triangle meshes to be deformed. Furthermore, the well known quardratic least square method for the Laplacian coordinates is employed in order to deform the control meshes. Because the mean value coordinates are continuous and smooth on the interior of control meshes, deforming operation of control meshes change the shape of polygon model while preserving the intrinsic surface detail. The effectiveness and validity of this novel approach was demonstrated by using it to deform large and complex polygon models with arbitrary topologies.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.53-56
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• 2001

Reverse engineering has been widely used for the shape reconstruction of an object without CAD data and it includes some steps such as scanning of a clay or wood model, and generating some manufacturing data in an STL file. A new approach to remove point data with Delaunay triangulation is introduced to deal with the size problems of STL file and the difficulties in the operation of RP process. This approach can be used to reduce a number of measuring data from laser scanner within a specified tolerance, thus it can avoid the time for handing point data during modeling process and the time for verifying and slicing STL model during RP process. Developed software enables the user to specify the criteria for the selection of group of triangles either by the angle between triangles or the percentage of triangles reduced, and thus RP models with accuracy will be helpful to automated process.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1055-1058
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• 2003

The robustness and reliability of vision algorithms is the key issue in robotic research and industrial applications. In this paper robust real time visual tracking in complex scene is considered. A common approach to increase robustness of a tracking system is the use of different model (CAD model etc.) known a priori. Also fusion or multiple features facilitates robust detection and tracking of objects in scenes of realistic complexity. Voting-based fusion of cues is adapted. In voting. a very simple or no model is used for fusion. The approach for this algorithm is tested in a 3D Cartesian robot which tracks a toy vehicle moving along 3D rail, and the Kalman filter is used to estimate the motion parameters. namely the system state vector of moving object with unknown dynamics. Experimental results show that fusion of cues and motion estimation in a tracking system has a robust performance.