• 한국정밀공학회지
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• 제11권5호
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• pp.88-97
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• 1994

We persent a method for kinematic calibration of open chain mechanisms based on the product of exponentials (POE) formula. The POE formula represents the forward kinematics of an open chain as a product of matrix exponentials, and is based on a modern geometric interpretation of classical screw theory. Unlike the kinematic parameters in the POE formula vary smoothly with changes in the joint axes;ad hoc methods designed to address the inherent singularities in the D-H parameters are therefore are therefore unnecessary. After introducing the POE formula, we derive a least-squares kinematic calibration algorithm for general open chain mechanisms. Simulation results with a 6-axis open chain are presented.

• International Journal of Automotive Technology
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• 제6권4호
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• pp.375-381
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• 2005

This paper presents linear algebraic equations in the form of recursive formula to compute elastokinematic characteristics of a suspension system. Conventional methods of elastokinematic analysis are based on nonlinear kinematic constrant equations and force equilibrium equations for constrained mechanical systems, which require complicated and time-consuming implicit computing methods to obtain the solution. The proposed linearized elastokinematic equations in the form of recursive formula are derived based on the assumption that the displacements of elastokinematic behavior of a constrained mechanical system under external forces are very small. The equations can be easily computerized in codes, and have the advantage of sharing the input data of existing general multi body dynamic analysis codes. The equations can be applied to any form of suspension once the type of kinematic joints and elastic components are identified. The validity of the method has been proved through the comparison of the results from established elastokinematic analysis software. Error estimation and analysis due to piecewise linear assumption are also discussed.

• 대한수학회보
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• 제25권2호
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• pp.261-266
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• 1988

• 대한수학회논문집
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• 제4권2호
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• pp.289-295
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• 1989

• Structural Engineering and Mechanics
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• 제54권4호
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• pp.793-807
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• 2015

Constructing the influence lines of forces of statically indeterminate structures is a traditional issue in structural engineering and mechanics. However, the existing kinematic method for establishing these force influence lines is an indirect or mixed approach by combining the force method with the theorem of reciprocal displacements, which is yet inconsistent with the kinematic method for statically determinate structure. This paper proposes the direct kinematic method in conjunction with the load-displacement differential relation for exactly constructing influence lines of reaction and internal forces of indeterminate structures. Firstly, through applying the principle of virtual displacement, the formula for influence lines of reaction and internal forces of indeterminate structure via direct kinematic method is derived based on the released structure. Then, a computational approach with a clear concept and unified procedure as well as wide applicability based on the load-displacement differential relation of beam is suggested to achieve conveniently the closed-form expression of force influence lines, and exactly draw them. Finally, three representative examples for constructing force influence lines of statically indeterminate beams and frame illustrate the superiority of the proposed method.

• 대한기계학회논문집
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• 제12권6호
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• pp.1265-1272
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• 1988

본 연구에서는 속도변환을 이용하여 기본체(base body)가 움직이는 경우에 대 한 일반적인 운동방정식을 유도하고, 이를 적절히 변형시킴으로써 로봇분야에서 이미 유도된 식과 비슷한 반복형태의 식을 얻을 수 있음을 보임으로써, 기계의 동력학 분야 에서 사용하고 있는 속도변환의 방법이 기본체가 고정되어 있는 경우가 대부분인 로봇 분야에서도 적용될 수 있음을 보이고자 한다. 또한 유도된 반복형태식을 이용하여 개방연쇄계(open-loop system)로 이루어진 기계시스템의 동력학 시뮬레이션에 적합한 알고리즘을 만들고 자동차를 예제로 택하여 유도된 방법의 타당성과 효율성을 검토하 였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.621-625
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• 1997

Recently, wash plate type hydraulic axial piston motors are being in extensively used in the world, because of simple design, lightweight, effective cost. But the structural problem of swash plate type hydraulic axial piston motor is the limited angle of swash plate and lateral force having a undesirable effect in piston. To solve these problems. a connecting rod mechanism. which is commonly used in hent axis type motors, is considered to be applied the swash plate cype motor. In this paper, kinematic analysis is done on the connecting rod mechanism. A series of formula are derived and numerical calculations are done for a set of motor parameters.

• 유공압시스템학회논문집
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• 제2권1호
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• pp.1-8
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• 2005

Recently, swash plate type hydraulic axial piston motors/pumps are being extensively used in the world, because of simple design, light weight and effective cost. Structural problem of the swash plate type motor/pump is that tilting angle of swash plate should be limited to relatively small value and lateral farce on pistons has an undesirable effect in reciprocating motion. To solve these problems, piston rod mechanism, which is commonly used in bent axis type motor/pump, is considered to be applied to the swash plate type motor/pump. In this paper, kinematic analysis was done on the piston rod mechanism. A series of formula were derived and numerical calculations were done for a set of motor parameters.

• 유공압시스템학회논문집
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• 제8권2호
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• pp.8-16
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• 2011

It is hard and complicated to analytically derive the volumetric-displacement formula of a gerotor pump/motor. Analytical formulas for calculating the volumetric-displacement are derived in this work, which is relatively easy and based upon vane lengths. The vane lengths mean the distances from axis of inner rotor or outer rotor to contact points between inner and outer rotors. Two kinds of formula were studied for two different kinematic motions of rotors. The first one is the case that outer rotor is fixed in space and inner rotor is in mixed motion of planetary revolution and rotation with respect to the spinning axis. And the second is the case that both inner and outer rotors simultaneously rotate. The proposed formula is verified through comparison with volumetric-displacement obtained from numerical CAD calculation.

• 물과 미래
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• 제18권2호
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• pp.175-185
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• 1985

본 연구는 유출해석을 위하여 저유함수모델의 상수와 유역의 수문인자 및 지형인자와의 관계를 명백히 할 수 있는 방법에 대하여 고찰하였다. 연구대상유역은 우리나라의 중요수계에 속하는 한강 금강 낙동강 영산강 유역의 8개소유역을 택하였다. 최적상수의 탐색은 수학적 최적치 탐색방법의 하나인 SDFP 법을 사용하였으며 적합성 검정에는 $\chi$2-기준을 적용하였다. 저유함수법과 kinematic wave 이론에 의하여 저유상수와 지대시간을 구하는 공식을 인도하였으며 kinematic wave 모델의 가정치와 저유함수 모델의 최적상수를 기준으로 하여 검토하였다. 주요한 결과를 요약하면 다음과 같다. 1) 저유함수법과 kinematic wave 모델의 상수 사이에는 서로 공통된 관계가 있다. 따라서 이 두 모델의 관계로부터 ⑬식을 얻었다. 2) 위에서 구한 공식을 간단히 하여 산지유역에서 실제적으로 적용될 수 있는 새로운 공식을 제안하였다. 3) 여기에서 제안된 방정식의 적합성을 검정하기 위하여 산지유역의 몇 개 지점에 몇 개의 홍수자료를 적용하여 이 방정식으로 구한 상수를 갖이고 저유함수법에 의하여 유출해석을 하여 제안식의 타당성을 확인하였다.