• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.78-89
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• 1991

This Paper presents an application example of the Adaptive Robust Servocontrol (ARSC) scheme, which is an explicit (or indirect) pole-assignment adaptive algorithm with the property of "robustness". The ARSC scheme is applied to an end-milling process for cutting force regulation. It is shown that the federate of an end-milling process can be maximized by the adaptive regulation of the peak cutting force through the ARSC scheme. The results of simulation study and real cutting experiment are presented. It has been verified that asymptotic regulation can be achieved with robustness against the slowly time-varying perturbations to the process model parameters, which are caused by nonlinear cutting dynamics. dynamics.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.1 no.1
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• pp.15-22
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• 2002

This study shows how the change of helix angle of different helix angle end mill affects machining accurracy. It was verified that cutting force are remarkably low when endmill has helix angle of different helix angle 250, 310, 370 and AE signal have less reationshap with the change of helix angle. Moreover, as the number of rotations are increases, the AE signal increased with the proportion to the number but cutting force are inversely proportional to the rotation.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.225-260
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• 2002

The purpose of this paper is to further extend the theoretical understanding of the dynamic end milling process and to derive a computational model to predict the milling force components. A comparative assessment of different cutting force models is performed to demonstrate that the instantaneous shear plane based formulation is physically sound and offers the best agreement with experimental results. The procedure for the calculation of the model parameters used in the cutting force model, based on experimental data, has been presented. The validity of the proposed computational model has been experimentally verified through a series of cutting tests.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.370-375
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• 2004

This paper presents an accurate cutting simulation and feedrate scheduling system for CNC machining. This system is composed of a cutting simulation part and a feedrate scheduling part. The cutting simulation part computes the geometric informations and calculates the cutting forces in CNC machining. The cutting force model using cutting-condition-independent coefficients was introduced for flat end milling and ball end milling. The feedrate scheduling part divides original blocks of NC code into smaller ones with optimized feedrates to adjust the peak value of cutting forces to reference forces. Some machining examples show that the developed system can control the cutting force at desired levels.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.2
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• pp.95-102
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• 2002

Due to the development of the CNC machine tool and CAM software, sculptured surface machining can be broadly used in die and mold industries and ball end milling process is often used for the sculptured surface machining. It is found out how feedrate affects the precision of the machining and also tried to study the most suitable feedrate in specific cutting condition. Two eddy current sensors were used far measuring tool deflections of X, Y axis, dynamometer for cutting force and roundness tester for roundness. It was found that the tool deflection is getting better as tool path is going to further from the center of convex surface. The reason is that the cutting force is increased as the tool approaches to the center. Examining the roundness, cutting force and tool deflection characteristics, it was found that the most suitable feedrate is 90mm/min in convex surface and 120mm/min in concave surface.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.5
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• pp.1572-1586
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• 1991

본 연구에서는 볼 엔드밀 공구를 사용한 코너가공에서 절삭력을 예측하고, 가 공중 공구의 회전주기에 대한 최대 수평합력(max. resulant force)을 일정하게 유지시 키는 모델을 개발하고, 코너가공에 적용한다. 또 금형가공에는 절삭시간을 많이 소 요하여 생산성이 떨어지게 하는 주요한 원인이 되기 때문에 최대 수평합력을 황삭가공 에 적합하도록 설정하면 본 연구의 결과로 이송속도를 결정할 수 있다.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.575-578
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• 1995

In general, the control of robot manipulator is classified into position control and force control. Position controllers give adequate performance when a manipulator is following a trajectory through space and end-effector has no contact with environment. However for most tasks performed by robot manipulator in industry, contact is made between the end-effector and manipulator's environment, so position control may not suffice. The objective of this study is to control both position of a manipulator and the contact forces generated at the hand by using a conceptually simple control law. Position and force control problem is decoupled into subtasts via taskspace formulation and inverse dynamics. Then, the position controllers are designed for the task space variable which represent tangent motion and the forte controllers are designed for the lash space variables which represent normal force.

• Korean Journal of Computational Design and Engineering
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• v.3 no.3
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• pp.161-167
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• 1998

Cutting forces in ball-end milling of slanted surfaces are calculated. The cutting area is determined from the Z-map of the surface geometry and current cutter location. The obtained cutting area is projected onto the cutter plane normal to the Z-axis and compared with cutting edge element location. Cutting force is calculated by integration of elemental cutting forces of engaged cutting edge elements. Experiments with various slanted angles were performed to verify the proposed cutting force estimation model. It is shown that the proposed method predicts cutting force effectively for any geometry including sculptured surfaces with cusp marks and surfaces with pockets and holes.

• Journal of Korean Society of Steel Construction
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• v.27 no.2
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• pp.251-260
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• 2015

The end plate connection is applied to beam-column moment connections in various forms. Such end plate connection displays changes in the behavioral characteristics, strength and stiffness, and energy dissipation capacity based on the thickness and length of the end plate, the number and diameter of the high strength bolt, the gauge distance of the high strength bolt, prying action force of the high strength bolt, and dimensions and length of the welds. Accordingly, this study has apprehended the axial tensile stiffness and prying action force of the high strength bolt connected on the tensile side based on the difference in thickness of the end plate, and was conducted to propose an analysis model for the prediction of such variables that affect the operating properties of the end plate. To achieve this, this study has conducted a three-dimensional non-linear finite-element analysis of the unstiffened expanding end plate connection by selecting only the thickness of the end plate as the variable.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.339-342
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• 1996

In this paper, the method for controlling PUMA robot using F/T sensor is described. In the part of the setup automation, robot is used. The F/T sensor is located at robot end-effector and various experiments are executed such as peg in hole, gripping objects, tool changing, etc.