• Structural Engineering and Mechanics
• /
• 제82권4호
• /
• pp.503-515
• /
• 2022

The multi-rigid-body matrix method (MRBMM) is a generalized modeling method for obtaining the displacements, forces, and dynamic characteristics of a compliant mechanism without performing inner-force analysis. The method discretizes a compliant mechanism of any type into flexure hinges and rigid bodies by implementing a multi-body mass-spring model using coordinate transformations in a matrix form. However, in this method, the deformations of bodies that are assumed to be rigid are inherently omitted. Consequently, it may yield erroneous results in certain mechanisms. In this paper, we present a multi-compliant-body matrix-method (MCBMM) that considers a rigid body as a compliant element, while retaining the generalized framework of the MRBMM. In the MCBMM, a rigid body in the MRBMM is segmented into a certain number of body nodes and flexure hinges. The proposed method was verified using two examples: the first (an XY positioning stage) demonstrated that the MCBMM outperforms the MRBMM in estimating the static deformation and dynamic mode. In the second example (a bridge-type displacement amplification mechanism), the MCBMM estimated the displacement amplification ratio more accurately than several previously proposed modeling methods.

• Structural Engineering and Mechanics
• /
• 제26권4호
• /
• pp.459-477
• /
• 2007

A bi-directional tuned mass damper (BTMD) in which a mass connected by two translational springs and two viscous dampers in two orthogonal directions has been introduced to control coupled lateral and torsional vibrations of asymmetric building. An efficient control strategy has been presented in this context to control displacements as well as acceleration responses of asymmetric buildings having asymmetry in both plan and elevation. The building is idealized as a simplified 3D model with two translational and a rotational degrees of freedom for each floor. The principles of rigid body transformation have been incorporated to account for eccentricity between center of mass and center of rigidity. The effective and robust design of BTMD for controlling the vibrations in structures has been presented. The redundancy of optimum design has been checked. Non dominated sorting genetic algorithm (NSGA) has been used for tuning optimum stages and locations of BTMDs and its parameters for control of vibration of seismically excited buildings. The optimal locations have been observed to be reasonably compact and practically implementable.

• 정보처리학회논문지A
• /
• 제8A권2호
• /
• pp.167-178
• /
• 2001

This paper presents a new methodology for specification and control of the motion of an articulated rigid body for the purposes of animation by coordinate transformations. The approach is to formulate the problem as a coordinate transformation from the joint space of the body to a user-defined animation space which is chosen for convenience in constraining the motion. Constraints are applied to the resulting coordinate transformation equations. It is sufficiently general so that it can be applied to all common types of control problems, including closed loop as well as open loop mechanisms. We also provided a new approach to simulate a closed loop mechanism, which is using animation space transformation technique. The method is formulated in detail and is demonstrated by animating the motion of an inchworm.

• 한국산업정보학회논문지
• /
• 제25권5호
• /
• pp.1-11
• /
• 2020

가상착용기술은 온라인 의류 쇼핑 활성화를 위해 중요한 기술이다. 최근 이미지 기반 가상착용기술은 의상과 착용 대상 신체의 3차원 정보가 필요하지 않다는 실용성 때문에 큰 관심을 받고 있다. 그러나 기존의 이미지 기반 알고리즘의 2차원 기하변형 방식의 한계로 인하여 대상 인물의 포즈와 의상 이미지의 형태가 큰 차이가 있는 경우 자연스러운 의상변형을 하지 못한다. 본 논문에서는 이러한 문제를 해결하기 위해 3차원 인체 모델을 이용하여 2차원 의상 사진으로 부터 의상의 3차원 모델을 생성하고, 대상 인물의 자세와 체형에 맞게 3차원 변형 후 렌더링하고 대상 인간 이미지와 혼합을 통하여 가상착용 이미지를 생성할 수 있다. 기존 연구에서 사용된 VITON 데이터 세트를 사용한 실험 결과는 3차원 변형이 요구되는 경우에 2차원 이미지 기반 가상착용 결과들에 비교했을 때 자연스러운 결과를 보인다.