• Journal of the Korean Society of Industry Convergence
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• v.24 no.6_2
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• pp.953-959
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• 2021

In this paper, the numerical inverse kinematics analysis is presented for a collaborative robot with an offset wrist. Robot manipulators with offset wrist are widely used in industrial applications, due to many advantages over those with wrist center and those with three parallel axes such as simple mechanical design, light weight, and so on. There may not exist a closed-form solution for a robot manipulator with offset wrist. A simple numerical method is applied to solve the inverse kinematics with offset wrist. Singularity is analyzed using Jacobian matrix and the numerical inverse kinematics algorithm is implemented on the real-time controller.

• Korean Journal of Mathematics
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• v.18 no.4
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• pp.425-440
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• 2010

Using Green's theorem, elliptic boundary value problems can be converted to boundary integral equations. A numerical methods for boundary integral equations are boundary elementary method(BEM). BEM has advantages over finite element method(FEM) whenever the fundamental solutions are known. Helmholtz type equations arise naturally in many physical applications. In a boundary integral formulation for the exterior Neumann there occurs a hypersingular operator which exhibits a strong singularity like $\frac{1}{|x-y|^3}$ and hence is not an integrable function. In this paper we are going to remove this hypersingularity by reducing the regularity of test functions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.837-842
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• 1994

The boundary element method was used for studying singularities of an interface crack with contact zones. Because the contact zone size was extremely small in a tention field, a large number of Gaussian points were is used for numerical integration of the Kernels. In order to estimate the contact zone size, iteration method was used. The interface crack tips with contact zones showed no oscillatory behavior and J-integral values across the interface were conserved.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.286-289
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• 2008

Mass of generator is one of the most important characteristic value especially direct drive type wind turbine. This paper introduce how to decease mass of generator rotor frame without declining generator performance. To obtain optimal design of rotor frame, sensitivity analysis using Taguchi method and RSM(response surface method) are have been performed.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.599-603
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• 2002

We propose a new meshfree method to be called the fast moving least square reproducing kernel collocation method(FCM). This methodology is composed of the fast moving least square reproducing kernel(FMLSRK) approximation and the point collocation scheme. Using point collocation makes the meshfree method really come true. In this paper, FCM Is shown to be a good method at least to calculate the numerical solutions governed by second order elliptic partial differential equations with geometric singularity or geometric multi-scales. To treat such problems, we use the concept of variable dilation parameter.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.383-388
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• 2003

This paper deals with the singular stresses developed in a polymer coating on concrete due to temperature change. The boundary element method is employed to investigate the behavior of interface stresses. Numerical results show that very large stress gradients are present at the interface comer and such stress singularity dominates a very small region relative to layer thickness. Since the exceedingly large stresses at the interface corner cannot be borne by coating materials, local yielding or delamination can occur in the vicinity of free surface.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2002.11a
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• pp.27-33
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• 2002

The residual thermal stresses at the interface corner between the elastic substrate and the viscoelastic thin film due to cooling from cure temperature down to room temperature have been studied. The polymeric thin film was assumed to be thermorheologically simple. The boundary element method was employed to investigate the nature of stresses on the whole interface. Numerical results show that very large stress gradients are present at the interface comer and such stress singularity might lead to edge cracks or delamination.

• Structural Engineering and Mechanics
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• v.5 no.6
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• pp.705-713
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• 1997

The residual thermal stresses at the interface corner between the elastic fiber and the viscoelastic matrix of a two-dimensional unidirectional laminate due to cooling from cure temperature down to room temperature were studied. The matrix material was assumed to be thermorheologically simple. The time-domain boundary element method was employed to investigate the nature of stresses on the interface. Numerical results show that very large stress gradients are present at the interface corner and this stress singularity might lead to local yielding or fiber-matrix debonding.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.6
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• pp.7-14
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• 1989

A trajectory control method being capable of singularity avoidance is proposed for a robot and positoner (R-P) system. In the proposed method, the damping factor of the Damped Least Square (DLS) method is adjusted by gradients of trajectory following errors so that the singularity avoidance can be achieved while mimimizing the errors. Two numerical examples are given by employing a Rhino robot with five degrees-of-freedom (d.o.f.) and two d.o.f's, where the method of maximizing the manipulagility the DLS method with a fixd damping factor and the proposed method are compared in terms of trajectory following errors, manipulabilities and joint velocities.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.13 no.1
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• pp.73-79
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• 2001

In this study, a submerged plate-type breakwater is considered, which is supported by elastic foundation. This breakwater makes use of wave phase interaction among the incident, diffracted and radiated waves. We apply a three-dimensional singularity distribution method within the linear potential theory in order to describe the wave field. The submerged plate is assumed to be rigid and the elastic support be a linear spring with constant stiffness. A typical rectangle plate is exemplified for numerical calculation. The thickness of the plate is carefully selected in order to guarantee the solution to be stable by checking the condition number of the system matrix. A parametric study is carried out for examining the effect of the stiffness of the elastic support on performance of the breakwater. We also examine the effect of the submerged depth.