• 제목/요약/키워드: Damper spring

검색결과 406건 처리시간 0.028초

Control Strategy for Modifiable Bipedal Walking on Unknown Uneven Terrain

  • Lee, Woong-Ki;Chwa, Dongkyoung;Hong, Young-Dae
    • Journal of Electrical Engineering and Technology
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    • 제11권6호
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    • pp.1787-1792
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    • 2016
  • Previous walking pattern generation methods could generate walking patterns that allow only straight walking on flat and uneven terrain. They were unable to generate modifiable walking patterns whereby the sagittal and lateral step lengths and walking direction can be changed at every footstep. This paper proposes a novel walking pattern generation method to realize modifiable walking of humanoid robots on unknown uneven terrain. The proposed method employs a walking pattern generator based on the 3-D linear inverted pendulum model (LIPM), which enables a humanoid robot to vary its walking patterns at every footstep. A control strategy for walking on unknown uneven terrain is proposed. Virtual spring-damper (VSD) models are used to compensate for the disturbances that occur between the robot and the terrain when the robot walks on uneven terrain with unknown height. In addition, methods for generating the foot and vertical center of mass (COM) of the 3-D LIPM trajectories are developed to realize stable walking on unknown uneven terrain. The proposed method is implemented on a small-sized humanoid robot platform, DARwIn-OP and its effectiveness is demonstrated experimentally.

Effect of dynamic absorber on the nonlinear vibration of SFG cylindrical shell

  • Foroutan, Kamran;Ahmadi, Habib
    • Advances in aircraft and spacecraft science
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    • 제7권4호
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    • pp.291-308
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    • 2020
  • In this paper, a numerical method is utilized to study the effect of a new vibration absorber on vibration response of the stiffened functionally graded (SFG) cylindrical shell under a couple of axial and transverse compressions. The material composition of the stiffeners and shell is continuously changed through the thickness. The vibration absorber consists of a mass-spring-damper system which is connected to the ground utilizing a linear local damper. To simplify, the spring element of the vibration absorber is called global potential. The von Kármán strain-displacement kinematic nonlinearity is employed in the constitutive laws of the shell and stiffeners. To consider the stiffeners in the model, the smeared stiffener technique is used. After obtaining the governing equations, the Galerkin method is applied to discretize the nonlinear dynamic equation of system. In order to find the nonlinear vibration responses, the fourth order Runge-Kutta method is utilized. The influence of the stiffeners, the dynamic absorber parameters on the vibration behavior of the SFG cylindrical shell is investigated. Also, the influences of material parameters of the system on the vibration response are examined.

이동질량을 고려한 단순지지된 교량의 진동수 및 공진현상 분석 (The Effect of Moving Mass on Resonance Phenomenon and Natural Frequency of a Simply Supported Beam)

  • 민동주;정명락;박성민;김문영
    • 한국소음진동공학회논문집
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    • 제26권1호
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    • pp.27-38
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    • 2016
  • The purpose of this study is to investigate the influence of moving mass on the vibration characteristics and the dynamic response of the simply supported beam. The three types of the moving mass(moving load, unsprung mass, and sprung mass) are applied to the vehicle-bridge interaction analysis. The numerical analyses are then conducted to evaluate the effect of the mass, spring and damper properties of the moving mass on natural frequencies and dynamic responses of the simply supported beam. Particularly, in the case of the sprung mass, variations of the natural frequency of simply supported beam are explored depending on the position of the moving mass and the frequency ratio of the moving mass and the beam. Finally the parametric studies on the resonance phenomena are performed with changing mass, spring and damper parameters through the dynamic interaction analyses.

행복의 수학적 모델링과 비선형 해석 (Mathematical Modelling of Happiness and its Nonlinear Analysis)

  • 김순환;최선경;배영철;박영호
    • 한국전자통신학회논문지
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    • 제9권6호
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    • pp.711-717
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    • 2014
  • 행복은 사회학과 심리학에서 주된 관심사로 연구되어 왔다. 본 논문에서는 Spring-Damper-Mass 시스템과 등가적으로 구성할 수 있는 새로운 2차계로 구성한 행복 모델을 제안하여 Duffing 방정식과 동일한 형태의 2차원 모델로 구성한다. Duffing 방정식에 비선형 항을 추가하고 행복 현상이 나타날 수 있는 외부 신호로서 주기적인 정현파와 가우시안 백색 잡음을 인가하였다. 그런 후 새로운 행복 모델에서 파라미터 변화에 따라 랜덤 운동, 주기 운동, 카오스 운동이 있음을 확인하였다.