• Title/Summary/Keyword: Dynamic Model

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A Flexible Multi-body Dynamic Model for Analyzing the Hysteretic Characteristics and the Dynamic Stress of a Taper Leaf Spring

  • Moon Il-Dong;Yoon Ho-Sang;Oh Chae-Youn
    • Journal of Mechanical Science and Technology
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    • v.20 no.10
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    • pp.1638-1645
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    • 2006
  • This paper proposes a modeling technique which is able to not only reliably and easily represent the hysteretic characteristics but also analyze the dynamic stress of a taper leaf spring. The flexible multi-body dynamic model of the taper leaf spring is developed by interfacing the finite element model and computation model of the taper leaf spring. Rigid dummy parts are attached at the places where a finite element leaf model is in contact with an adjacent one in order to apply contact model. Friction is defined in the contact model to represent the hysteretic phenomenon of the taper leaf spring. The test of the taper leaf spring is conducted for the validation of the reliability of the flexible multi-body dynamic model of the taper leaf spring developed in this paper. The test is started at an unloaded state with the excitation amplitude of $1{\sim}2mm/sec$ and frequency of 132 mm. First, the simulation is conducted with the same condition as the test. Then, the simulations are conducted with various amplitudes in a loaded state. The hysteretic diagram from the test is compared with the ones from the simulation for the validation of the reliability of the model. The dynamic stress analysis of the taper leaf spring is also conducted with the developed flexible multi-body dynamic model under a dynamic loading condition.

Development and Validation of an Improved 5-DOF Aircraft Dynamic Model for Air Traffic Control Simulation (항공교통관제 시뮬레이션을 위한 개선된 5 자유도 항공기 운동 모델 개발 및 검증방안 연구)

  • Kang, Jisoo;Oh, Hyeju;Choi, Keeyoung;Lee, Hak-Tae
    • Journal of Advanced Navigation Technology
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    • v.20 no.5
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    • pp.387-393
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    • 2016
  • To perform realistic air traffic control (ATC) simulation in various air traffic situations, an aircraft dynamic model that is accurate and efficient is required. In this research, an improved five degree of freedom (5-DOF) dynamic model with feedback control and guidance law is developed, which utilizes selected performance data and operational specifications from the base of aircraft data (BADA) and estimations using aircraft design techniques to improve the simulation fidelity. In addition, takeoff weight is estimated based on the aircraft type and flight plan to improve simulation accuracy. The dynamic model is validated by comparing the simulation results with recorded flight trajectories. An ATC simulation system using this 5-DOF model can be used for various ATC related research.

Experimental Evaluation of Feedforward Control Based on the Dynamic Models of A Direct Drive SCARA Robot (직접구동 평면 다관절 로봇의 동역학적 모델에 따른 피드포워드 제어의 실험적 평가)

  • Hong, Yun-Sik;Kang, Bong-Su;Kim, Su-Hyeon;Park, Gi-Hwan;Kwak, Yun-Geun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.1
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    • pp.146-153
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    • 1996
  • A SCARA type direct drive robot which can be used in the assembly operation was designed and manufactured. Graphite fiber epoxy composite material was used in the fabrication of the robot arm structure in order to improve the speed of the robot arm with a high damping effect. For model-based control and sensitivity analysis of system parameters, the dynamic model of robot arm and drive servo amplifier parameters such as equivalent gains of PWM driver and velocity gains of servo system were estimated from frequency response tests. The complete dynamic model for overall robot system was used in the simulation of the open-loop control. The simulation results agreed reasonably well to the experimental results. The feedforward control using the dynamic models improved the trajectory tracking performance, decreasing the tracking error by factor of three compared with PID control. This study found that the inverse dynamic model of the robot arm including the drive servo system showed better performances than the case of arm dynamic model only.

A Study on Vibration Characteristics Caused by Backlash of Gearbox in Escalator with Chain-sprocket Drive Mechanism (체인-스프라켓 메커니즘을 갖는 에스컬레이터에서 기어박스 백래시로 인한 이상진동에 관한 연구)

  • 권이석;홍성욱;박노길
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.13 no.5
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    • pp.341-347
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    • 2003
  • This paper presents an improved escalator dynamic model so as to reflect the experimental observation on the pseudo-resonance affected by load applied. The experimental evidence reveals that backlash on gearbox as well as sag of driving Chain are most critical factors to the pseudo-resonance in escalators. The dynamic model effectively reflects vibration characteristics measured in real escalators with respect to different conditions of driving chain and the number of passengers. For validation of the dynamic model developed. numerical results from the model are compared with experimental results. The developed model and its simulation results are used rigorously for the design of escalator systems in enhancing the ride comfort.

Dynamic Model for Ocean Thermal Energy Conversion Plant with Working Fluid of Binary Mixtures

  • Nakamura, Masatoshi;Zhang, Yong;Bai, Ou;Ikegami, Yasuyuki
    • 제어로봇시스템학회:학술대회논문집
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    • pp.2304-2308
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    • 2003
  • Ocean thermal energy conversion (OTEC) is an effective method of power generation, which has a small impact on the environment and can be utilized semi-permanently. This paper describes a dynamic model for a pilot OTEC plant built by the Institute of Ocean Energy, Saga University, Japan. This plant is based on Uehara cycle, in which binary mixtures of ammonia and water is used as the working fluid. Some simulation results attained by this model and the analysis of the results are presented. The developed computer simulation can be used to actual practice effectively, such as stable control in a steady operation, optimal determination of the plant specifications for a higher thermal efficiency and evaluation of the economic prospects and off-line training for the operators of OTEC plant.

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Dynamic Modeling and Model Reduction for a Large Marine Engine

  • Kim, Chae-Sil;Jung, Jong-Ha;Park, Hyung-Ho
    • Journal of Advanced Marine Engineering and Technology
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    • v.27 no.4
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    • pp.520-525
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    • 2003
  • This article provides a dynamic modeling methodology of engines to be accurate with a small number of degrees of freedom for an active vibration control using a top bracing. First. a finite element (FE) model for the engine structure is constructed so that the size of model is as small as possible where the dynamic characteristics of engine are ensured. Second. a technique is studied to obtain the exact mass and stiffness matrices of the FE model. The size of matrices from the FE model is still too large to apply. Finally, a model reduction is. therefore. conducted to make an appropriate dynamic model for designing and simulating a top bracing. In this article, a dynamic model of a large 9 cylinder engine is constructed and reviewed by comparing its natural frequencies and steady state reponses with those of experimental data provided by manufacturer.

Multi-Body Dynamic Modeling for a Flexible Rotor and Vibration Control using a Novel Phase Adjusting Technique (유연 회전축의 다물체 동역학 모델링 및 위상 조절법을 이용한 진동 제어)

  • Jung, Hoon-Hyung;Jo, Hyeon-Min;Kim, Chae-Sil;Cho, Soo-Yong
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.1
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    • pp.87-92
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    • 2011
  • This article proposes a new technique of the dynamic model using multi-body dynamic analysis tool for a flexible main spindle rotor system with a novel phase adjusting control technique for the purpose of an active control of rotor vibration. The dynamic model is used as a plant model. Also in order to make control system, a component parameters and phase controller is composed and simulated by SIMULINK. The vibration is reduced to 50%. Therefore the ADAMS dynamic model for the flexible main spindle rotor and the phase adjusting control techniques may be effective for the suppressing the vibration and helpful for the future active control for rotor vibration.

Dynamic Analysis of a Washing Machine Using a Multi-body Dynamic Model (다물체 동역학 모델을 이용한 세탁기의 동적 해석)

  • Kim, Tae-Jin;Kim, Byung-Jin;Kim, Seung-Oh;Min, Je-Hong;Chung, Jin-Tai
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.1
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    • pp.88-93
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    • 2012
  • In this study, a multi-body dynamic model is developed for a washing machine and the dynamic behaviors of the machine are investigated. The mechanical properties such as spring constants and damping factors are measured from vibrational experiments. With these experimentally obtained mechanical properties, a computer simulation model for the washing machine is established by using a commercial multi-body dynamics software DAFUL. In order to verify the developed simulation model, the dynamic responses computed from simulation are compared to the responses measured from vibration experiments. In addition, the effects of the stiffness and damping factors on the dynamic responses are also analyzed.

Dynamic control modeling of the GMA welding system using the system identification and weld pool width control (시스템 식별을 이용한 GMA 용접 시스템의 동적 제어 모델링과 용융지폭 제어)

  • 김동철;이세헌;엄기원
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.4
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    • pp.97-103
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    • 1997
  • Designing a feedback controller requires a dynamic model of the process to be controlled. But the GMA welding process models have not been fully developed for many reasons such as complexity of the welding process and lack of reliable sensors. Because of the complexity of the welding system, we obtained a dynamic model for control using system identification routines, rather than derived a model from fundamental physical laws. The controller was designed based on the experimentally derived linear dynamic model of the welding process. In order to demonstrate application of the designed controller, the simulation was carried out.

Steering Model for Vehicle Dynamic Analysis (차량 동력학 해석을 위한 조향장치 모델링)

  • Tak, Tae-Oh;Kim, Kum-Cheol;Yoon, Jung-Rak
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.12
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    • pp.214-221
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    • 1999
  • In this research, a power-assisted steering system is modeled as a part of a full vehicle dynamic model. The dynamic model of the steering system incorporates hydraulic and dynamic relations between major parts of a steering system, such as steering column, control valve, rack and pinion gear. Through an experimental setup of the steering system, the steering system model is validated. The steering model is included in a full vehicle dynamic model of a car, where kinematic relations between steering and suspension system are defined, and various simulations are performed to evaluate the performance of steering system in conjunction with overall dynamic performance of the vehicle.

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