• Title/Summary/Keyword: Three Degree of Freedom

Search Result 350, Processing Time 0.036 seconds

A Dynamic Analysis of Wheel Forces distribution of KTX locomotive for Interaction of PSC box Girder Bridge (PSC 박스거더 교량의 상호작용에 의한 KTX 동력차의 윤하중 분포 해석)

  • Oh, Soon-Taek;Lee, Dong-Jun;Sim, Young-Woo;Yun, Jun-Kwan;Kim, Han-Su
    • Proceedings of the KSR Conference
    • /
    • 2011.05a
    • /
    • pp.680-689
    • /
    • 2011
  • A dynamic analysis procedure is developed to provide a comprehensive estimation of the dynamic response spectrum for locomotive's wheels running over a Pre-Stressed Concrete (PSC) box girder bridge on the Korea high speed railway. The wheel force spectrum with the bridge behavior are analyzed as the dynamic procedure for various running speeds (50~450km/h). The high-speed railway locomotive (KTX) is used as 38-degree of freedom system. Three displacements(vertical, lateral, and longitudinal) and three rotational components (pitching, rolling, and yawing). For one car-body and two bogies as well as five movements except pitching rotation components for four wheel axes forces are considered in the 38-degree of freedom model. Three dimensional frame element is used to model of the PSC box girder bridges, simply supported span length of 40m. The irregulation of rail-way is derived using the exponential spectrum density function under assumption of twelve level tracks conditions based on the normal probability procedure. The dynamic responses of bridge passing through the railway locomotive with high-speed analyzed by Newmark-${\beta}$ method and Runge-Kutta method are compared and contrasted considering the developed models of bridge, track and locomotive comprehensively. The dynamic analyses of wheel forces by Runge-Kutta method which are able to analyze the forces with high frequency running on the bridge and ground rail-way are conducted. Additionally, wheel forces spectrum and three rotational components of vehicle body for three typical running speeds is also presented.

  • PDF

Simplified projective transform for reconstruction of cylindrical panorama (실린더 파노라마 영상의 재구성을 위한 단순화된 사영 변환)

  • Lee Kang-Ho
    • Journal of the Korea Society of Computer and Information
    • /
    • v.11 no.2 s.40
    • /
    • pp.169-175
    • /
    • 2006
  • In this paper we propose a method of reconstruction of cylindrical panorama using simplified projective transform from the panning image on the fixed camera. For the practical construction of cylindrical panorama we consider the rotation of the camera on the Y-axis only, even though considering the rotation components on all of the X,Y,Z axis on three-dimensional space for projective transform between general panoramas. The restriction mentioned above simplifies projective transform with existing 8 degrees of freedom into the one with 4 degrees of freedom. In the results, overall computation for projective transform can be decreased to the great extents in quantify, because the number of corresponding points required for inducing the transforming formula is gone down by half. Proposed algorithm from the simulation carried out in this paper shows similar performance and decreased computational quantity compared with existing algorithm. Also, it shows the construction of cylindrical panorama using simplified projective transform.

  • PDF

Multi Degree of Freedom Linear Electric Generator for Structural Concerns and Electric Generation Improvement of the Linear Electric Generator in a Vehicle Suspension (차량 현가장치 선형 발전기 구조 검토 및 발전량 향상을 위한 다자유도 선형 발전기)

  • Choi, Ji-Hyun;Kim, Jin Ho
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.15 no.9
    • /
    • pp.5452-5459
    • /
    • 2014
  • A resonance linear electric generator in a vehicle suspension is a system that performs self-electric generation by collecting the vibration energy when a vehicle runs on a road, and takes the resonance phenomenon to derive large electric generation from slight road surface vibrations. In this paper, the motions of an armature in three different electric generator structures were simulated and the actual generation quantity was calculated and compared with these results. Furthermore, when the vehicle runs on the road, the design improvement for a multi-degree of freedom electric generator was conducted to make the resonance respond to various excitation frequencies, and the change in the resonance points and generation quantity were identified.

A Dynamic Analysis of PSC Box Bridge Varying Span Lengths for Increased Speeds of KTX (고속철 속도변화에 대한 PSC박스 교량의 경간길이 별 동적해석)

  • Oh, Soon Taek;Lee, Dong Jun;Shim, Young Woo;Yun, Jun Kwan
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.15 no.4
    • /
    • pp.204-211
    • /
    • 2011
  • A dynamic analysis procedure is developed to provide a better estimation of the dynamic responses of bridge during the passage of high speed railway vehicles. Particularly, a three dimensional numerical model including the structural interaction between high speed vehicles, bridges and railway endures to analyse accurately and evaluate with in-depth parametric studies for dynamic responses of various bridge span lengths running KTX railway locomotive up to increasing maximum speed(450km/h). Three dimensional frame element is used to model the simply supported pre-stressed concrete (PSC) box bridges for four span lengths(40~25m). Track irregularity employed as a stationary random process from the given spectral density functions and irregularities of both sides of the track are assumed to have high correlation. The high-speed railway vehicle (KTX) is used as 38-degree of freedom system. Three displacements (Vertical, lateral, and longitudinal) as well as three rotational components (Pitching, rolling, and yawing) are considered in the 38-degree of freedom model. The dynamic amplification factors are evaluated by the developed procedure under various traveling conditions, such as track irregularity camber, train speed and ballast. The dynamic analysis such as Newmark-${\beta}$ and Runge-Kutta methods which are able to analyse considering the dynamic impact factors are compared and contrasted.

Kinematic and dynamic analysis of a spherical three degree of freedom joint rehabilitation exercise equipment (3자유도 구형관절 재활운동기기의 기구학 및 동역학 해석)

  • Kim, Seon-Pil
    • Journal of Korea Society of Industrial Information Systems
    • /
    • v.14 no.4
    • /
    • pp.16-29
    • /
    • 2009
  • This paper investigates the kinematic and dynamic analysis of a spherical three degree of freedom parallel joint module, which is used in the exercise equipment for balance and leg-strength improvement of aged people. The joint module has three dyads which consist of two links and three revolute joints, and their all joints intersect at the global point located at the module's center. The paper shows the explicit mathematical procedure for deriving the closed form solutions in the inverse and forward position analysis of this parallel joint module. In velocity and acceleration analysis, we derived relations for joint velocities and accelerations of dyads and rotational velocity and acceleration of the top plate. For applying this module to rehabilitation exercise, we determined the dynamic model of the Korean males in their 50s and examined the model's results by dynamic model simulation.

Random Vibration Analysis of Thick Composite Laminated Plate Using Mixed Finite Element Model (1) (혼합유한요소모델을 이용한 두꺼운 복합적층판의 불규칙 진동해석(1)-이론적 고찰)

  • Seok, Keun-Yung;Kang, Joo-Won
    • 한국공간정보시스템학회:학술대회논문집
    • /
    • 2004.05a
    • /
    • pp.190-196
    • /
    • 2004
  • Thick composite laminated plates is considered in 3D finite-element. To consider continuity of transverse stresses and displacement field, mixed finite-element has been developed by using layerwise theory and the minimum potential energy principle. Mixed finite-element has been enforced through the thick direction, Z, of a laminated plate by considering six degree-of-freedoms per node. Six degree-of-freedoms are three displacement components in the coordinate axes directions and three transverse stress components ${\sigma}_z,\;{\tau}_{xz},\;{\tau}_{yz}$. The model maintain the fundamental elasticity relations that are stress-strain relation and displacement-strain relation, because the transverse stress components invoked as nodal degrees of freedom by using the fundamental elasticity relationship between th components of stress and displacement. Random vibration analysis of the model is performed by computing consistent mass matrix and computing covariance in frequency domain technique.

  • PDF

Evolutionary computational approaches for data-driven modeling of multi-dimensional memory-dependent systems

  • Bolourchi, Ali;Masri, Sami F.
    • Smart Structures and Systems
    • /
    • v.15 no.3
    • /
    • pp.897-911
    • /
    • 2015
  • This study presents a novel approach based on advancements in Evolutionary Computation for data-driven modeling of complex multi-dimensional memory-dependent systems. The investigated example is a benchmark coupled three-dimensional system that incorporates 6 Bouc-Wen elements, and is subjected to external excitations at three points. The proposed technique of this research adapts Genetic Programming for discovering the optimum structure of the differential equation of an auxiliary variable associated with every specific degree-of-freedom of this system that integrates the imposed effect of vibrations at all other degrees-of-freedom. After the termination of the first phase of the optimization process, a system of differential equations is formed that represent the multi-dimensional hysteretic system. Then, the parameters of this system of differential equations are optimized in the second phase using Genetic Algorithms to yield accurate response estimates globally, because the separately obtained differential equations are coupled essentially, and their true performance can be assessed only when the entire system of coupled differential equations is solved. The resultant model after the second phase of optimization is a low-order low-complexity surrogate computational model that represents the investigated three-dimensional memory-dependent system. Hence, this research presents a promising data-driven modeling technique for obtaining optimized representative models for multi-dimensional hysteretic systems that yield reasonably accurate results, and can be generalized to many problems, in various fields, ranging from engineering to economics as well as biology.

Wind-induced coupled translational-torsional motion of tall buildings

  • Thepmongkorn, S.;Kwok, K.C.S.
    • Wind and Structures
    • /
    • v.1 no.1
    • /
    • pp.43-57
    • /
    • 1998
  • A three-degree-of-freedom base hinged assembly (BHA) for aeroelastic model tests of tall building was developed. The integral parts of a BHA, which consists of two perpendicular plane frames and a flexural pivot, enable this modeling technique to independently simulate building translational and torsional degree-of-freedom. A program of wind tunnel aeroelastic model tests of the CAARC standard tall building was conducted with emphasis on the effect of (a) torsional motion, (b) cross-wind/torsional frequency ratio and (c) the presence of an eccentricity between center of mass and center of stiffness on wind-induced response characteristics. The experimental results highlight the significant effect of coupled translational-torsional motion and the effect of eccentricity between center of mass and center of stiffness on the resultant rms acceleration responses in both along-wind and cross-wind directions especially at operating reduced wind velocities close to a critical value of 10. In addition, it was sound that the vortex shedding process remains the main excitation mechanism in cross-wind direction even in case of tall buildings with coupled translational-torsional motion and with eccentricity.

Experimental Framework for Controller Design of a Rotorcraft Unmanned Aerial Vehicle Using Multi-Camera System

  • Oh, Hyon-Dong;Won, Dae-Yeon;Huh, Sung-Sik;Shim, David Hyun-Chul;Tahk, Min-Jea
    • International Journal of Aeronautical and Space Sciences
    • /
    • v.11 no.2
    • /
    • pp.69-79
    • /
    • 2010
  • This paper describes the experimental framework for the control system design and validation of a rotorcraft unmanned aerial vehicle (UAV). Our approach follows the general procedure of nonlinear modeling, linear controller design, nonlinear simulation and flight test but uses an indoor-installed multi-camera system, which can provide full 6-degree of freedom (DOF) navigation information with high accuracy, to overcome the limitation of an outdoor flight experiment. In addition, a 3-DOF flying mill is used for the performance validation of the attitude control, which considers the characteristics of the multi-rotor type rotorcraft UAV. Our framework is applied to the design and mathematical modeling of the control system for a quad-rotor UAV, which was selected as the test-bed vehicle, and the controller design using the classical proportional-integral-derivative control method is explained. The experimental results showed that the proposed approach can be viewed as a successful tool in developing the controller of new rotorcraft UAVs with reduced cost and time.

A Study on the Control of Multi-Input Hydraulic System for Robot Leg using LQR Technique (LQR 기법을 이용한 로봇다리의 다중입력 유압시스템 제어에 관한 연구)

  • Yoo, Sam-Hyeon;Lim, Soo-Chul
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.12 no.4
    • /
    • pp.540-547
    • /
    • 2009
  • In the near future, military robots are likely to be substituted for military personnel in the field of battle. The power system of a legged robot is considerably more complex than the one used for a land vehicle because of the coordination and stability issues due to the large number of degree of freedom. In this paper, a servovalve-piston combination system for a straight-line motion of robot leg is modeled as three degree of freedom based on double inputs and single output transfer function. The output is the displacement of piston from neutral. The inputs are valve displacement from neutral and arbitrary load force in this system. LQR(Linear Quadratic Regulator) technique is applied in order to achieve robust stability and fast responses of the system. The Kalman filter loop, rejection of disturbance and noise, riccati equation, filter gain matrix, and frequency domain equality are analyzed and designed.