• Journal of the Korean Society for Precision Engineering
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• v.18 no.7
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• pp.9-18
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• 2001

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.202-206
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• 2001

Machine tool chatter is the self-excited vibration generated by chip thickness variation and severely degrades the quality of machined surface. The incidence of chatter is greatly affected by the dynamic characteristics of machine tool structure. Therefore, the cutting dynamics in the parallel machine tool is to be carefully studied considering the dynamic characteristics of parallel mechanism. In this paper, the vibration model of parallel machine tool is derived, in which the legs of the parallel mechanism are considered as spring-damper systems. The chatter stability charts for various machining parameters are examined with the example of the cubic parallel mechanism that is specially designed for machine tool use.

• ICROS
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• v.4 no.5
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• pp.12-15
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• 1998

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.492-495
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• 2001

In order to utilize a parallel machine tool for CAM system, the development of adequate interpolator is necessary. This paper presents a quintic B-spline interpolator with algorithm of limiting maximum interpolation error. The favored property of near arc-length parametrization in the curve representation is used in the implementation of the reference command generation. Then, this interpolator is applied to cubic parallel manipulator to show its validity.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.1003-1006
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• 2002

In machining free-form curves with a machine tool equipped with parallel device, improving contouring accuracy is very important. In this paper, we present contouring control algorithm far parallel machine tool. The relation between the error in Joint space and the error in catesian space is evaluated, and we estimate contouring error vector which efficiently determines the variable gains for the cross coupled control. To show the validity of the algorithm, the contouring control is simulated for free form contour trajectory in cubic parallel machine tool model.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.535-540
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• 2000

This paper presents the development of a Parallel-Typed CNC Machining Tool. It is specially designed to machine a complex shaped workpiece by controlling the orientation of the tool. The inverse/direct kinematics of a parallel mechanism is derived and implemented in a PC based controller. With graphics icons, the GUI (Graphic User Interface) program is developed for the CNC programing. The calibration is accomplished by geometric constraint motion, which is a parallel motion of the platform with respect to a table. The calibration result is introduced and the future study is proposed.

• Journal of Welding and Joining
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• v.17 no.3
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• pp.17-21
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• 1999

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.284-289
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• 2002

In this paper, we develop a six-axes machining center tool(MCT) and CAD/CAM system based RAD Tool Program. The MCT consists of two mechanical parts, i.e., a X-Y-Z Cartesian coordinate typed MCT and a parallel-typed tilting table. Kinematics and singularity are accomplished to design the parallel-typed tilting table, and RAD Tool Program Is developed for the six-axes MCT, which requires the commands of position as well as orientation for machining of complex shape. In RAD Tool, the CAD/CAM system has a tool path generator, NC code generator and a graphic simulator. This paper designs the parallel-typed tilting table to meet the desired specification and presents the results of CAD/CAM system based RAD Tool Program.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.8
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• pp.878-885
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• 2011

A kinematically-hybrid 5-axis machine tool is analyzed from the perspective of machine tool design. Its kinematic characteristics are pointed out, which should be considered during the conceptual design process. A result of the structural analysis of the machine is presented, which is performed during the detailed design process. It is also presented how we improve the thermal characteristics of the machine tool by changing the installation position of the actuators.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.3
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• pp.1-7
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• 2008

This paper describes the kinematics which is a new type of parallel manipulator, and the neural network is applied to solving the forward kinematics problem. The parallel manipulator called it as a Stewart platform has an easy and unique solution about the inverse kinematics. However, the forward kinematics is difficult to get a solution because of the lack of an efficient algorithm caused by its highly nonlinearity. This paper proposes the neural network scheme of an Newton-Raphson method alternatively. It is found that the neural network can be improved its accuracy by adjusting the offset of the obtained result.