• Title/Summary/Keyword: Moving Force

Search Result 809, Processing Time 0.028 seconds

Optimal design of tuned mass damper considering the friction between the moving mass and the rail (레일의 운동마찰력을 고려한 TMD 최적 설계)

  • Lee, Sang-Hyun;Woo, Sung-Sik;Cho, Seung-Ho;Chung, Lan
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2007.05a
    • /
    • pp.582-587
    • /
    • 2007
  • In this study, based on the results from the sinusoidal base excitation analyses of a single degree of freedom system with a tuned mass damper (TMD), it is verified that optimal friction force can improve the performance of a TMD like a linear viscous damper which has been usually used in general TMD. The magnitude of the optimal friction increases with increasing mass ratio of the TMD and decreases with increasing structural damping. Particularly, it is observed that the optimized friction force gives better control performance than the optimized viscous damping of the TMD. However, because the performance of the TMD considerably deteriorates when the friction force increases over the optimal value, it is required to keep the friction force from exceeding the optimal value.

  • PDF

Analysis of Door Effort using 2D Model (2차원 모델을 이용한 도어 개폐력 해석)

  • 김창원;강성종
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.11 no.3
    • /
    • pp.131-137
    • /
    • 2003
  • Proper door effort, required force to open or close a vehicle door, is an essential door design factor for the safety of passengers and pedestrians. Section shape of the door checker arm is the most influential design parameter for achieving a door effort design target. In this research. an analysis procedure to predict door effort using a simplified plane strain finite element model wes investigated for two passenger cars, for which mechanism of checker systems were: different. The variation of checker arm force to be required during moving on arm in opening and closing direction was estimated through analysis, and the result was transformed to the door effort with respect to door opening angle by considering door characteristics. Also, the self·closing force due to door weight was theoretically calculated and added to the door effort from checker arm force. Finally the estimated results of door effort were compared with test results.

Precise contact force control of a flip chip mounting head system

  • Shim, Jaehong;Cho, Youngim;Oh, Yeontaek
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 2002.10a
    • /
    • pp.109.1-109
    • /
    • 2002
  • This paper presents a macro/micro flip chip mounting head system for precise force control. In the proposed macro/ micro system, the macro actuator is conventional do servomotor with a ball screw mechanism and the micro actuator is a voice coil motor(VCM) that consists of four NdFeB magnets and a winded moving coil. For force control, a sensitive strain-gauge force sensor is mounted in the micro actuator. Through harmonic motion between macro and micro actuator, we would like to get precise contact force control when small sized flip chip is mounted on flexible substrate in high speed. In order to show the effectiveness of the proposed macro/micro flip chip mounting head system, we com...

  • PDF

Development of n Low Frequency Vibration Shaker Using Force Frequency Shifting (가진주파수 이동현상을 이용한 저주파 가진기의 개발)

  • Lee, Gun-Myung;L.Koss;Lee, Jung-Soo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2002.11a
    • /
    • pp.324.2-324
    • /
    • 2002
  • If a sinusoidal excitation force moves back and forth along a structure with a certain frequency, the structure will be excited with the difference frequency of these two frequencies. A low frequency vibration shaker has been developed using this force frequency shifting without actually moving a shaker. The shaker consists of an ordinary eccentric mass shaker, a plate, constant springs, and time varying dampers. The dampers are fumed on and off in a sequential manner to simulate a traveling slide of an excitation force. (omitted)

  • PDF

Research of the cutting force measuring system using feed drive system built in load cell (이송계에 부착시킨 로드셀을 이용한 절삭력 측정시스템에 관한 연구)

  • 강은구;이상조
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2000.05a
    • /
    • pp.595-598
    • /
    • 2000
  • This paper presents new cutting force measuring system for milling process. Usually, tool dynamometer is the most appropriate measuring tool in an analysis of cutting mechanism. High price and limited space, however, make it difficult to be in-situ system for controllable milling process. Although an alternative using AC current of servomotor has been suggested, it is unsuitable for cutting force control because of low bandwidth and noise. We suggest new cutting force measuring system, using two load cell placed between moving table and nut of ballscrew, and modelled on the system statically and dynamically. And to verify the accuracy of the proposed system, a series of carefully conducted experiments were carried out. Experiment results show that models are in reasonably good agreement with the experiment data.

  • PDF

A Study on Intelligent Trajectory Control for Prosthetic Arm by Pattern Recognition & Force Estimation Using EMG Signals (근전도신호의 패턴인식 및 힘추정을 통한 의수의 지능적 궤적제어에 관한 연구)

  • 장영건;홍승홍
    • Journal of Biomedical Engineering Research
    • /
    • v.15 no.4
    • /
    • pp.455-464
    • /
    • 1994
  • The intelligent trajectory control method that controls moving direction and average velocity for a prosthetic arm is proposed by pattern recognition and force estimations using EMG signals. Also, we propose the real time trajectory planning method which generates continuous accelleration paths using 3 stage linear filters to minimize the impact to human body induced by arm motions and to reduce the muscle fatigue. We use combination of MLP and fuzzy filter for pattern recognition to estimate the direction of a muscle and Hogan's method for the force estimation. EMG signals are acquired by using a amputation simulator and 2 dimensional joystick motion. The simulation results of proposed prosthetic arm control system using the EMG signals show that the arm is effectively followed the desired trajectory depended on estimated force and direction of muscle movements.

  • PDF

Electromagnetic Force Calculation using Magnetic Vector Potentials in 3-D Problems (자기벡터포텐셜을 이용한 3차원 전자력 계산)

  • Yang, Jae-Jin;Lee, Bok-Yong;Lee, Byung-Hoan;Lee, Ki-Sik
    • Proceedings of the KIEE Conference
    • /
    • 1994.07a
    • /
    • pp.153-155
    • /
    • 1994
  • Electric machines such as motors which have moving parts are desgined for producing mechanical force or torque. The accurate calculation of electromagnetic force and torque is important in the design these machines, Electromagnetic force calculation method using the results of Finite Element Method(FEM) has been presented variously in 2-D problems. Typically the Maxwell's Stress Tensor method and the method of virtual work are used. In the problems including current source, magnetic vector potentials(MVP) have mostly been used as an unknown variables for field analysis by numerical method; e, g. FEM. This paper, thus, introduces both methods using MVP in 3-D case. To verify the usefulness of presented methods, a solenoid model is chosen and analyzed by 3-D and axisymmetrical FEM. In each case, the calculated force are tabulated for several mesh schemes.

  • PDF

Optimal Design of Tuned Mass Damper Considering the Friction between the Moving Mass and the Rail (레일의 운동마찰력을 고려한 TMD 최적 설계)

  • Lee, Sang-Hyun;Woo, Sung-Sik;Cho, Seung-Ho;Chung, Lan
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.17 no.6 s.123
    • /
    • pp.553-559
    • /
    • 2007
  • In this study, based on the results from the sinusoidal base excitation analyses of a single degree of freedom system with a tuned mass damper (TMD), it is verified that optimal friction force can improve the performance of a TMD like a linear viscous damper which has been usually used in general TMD. The magnitude of the optimal friction increases with increasing mass ratio of the TMD and decreases with increasing structural damping. Particularly, it is observed that the optimized friction force gives better control performance than the optimized viscous damping of the TMD. However, because the performance of the TMD considerably deteriorates when the friction force increases over the optimal value, it is required to keep the friction force from exceeding the optimal value.

Postural Control During Virtual Moving Surround Stimulation in Patients with Brain Injury (뇌기능 장애 환자의 가상 환경 움직임(Virtual Moving Surround) 자극에 따른 자세 균형 제어)

  • 김연희;최종덕;이성범;김종윤;이석준;박찬희;김남균
    • Science of Emotion and Sensibility
    • /
    • v.5 no.4
    • /
    • pp.67-75
    • /
    • 2002
  • The purpose of this study is to assess the ability of balance control in virtual moving surround stimulation using head mount display (HMD) device and force platform in patients with brain injury. Fifteen patients with stroke (mean age 54.47 yrs) and fifteen healthy normal persons participated. COP parameters were obtained total path distance, frequency of anterior-posterior and medial-lateral component by FFT analysis, weight-spectrum analysis in the two different conditions; (1) during comfortable standing with opened or closed eyes, (2) during virtual moving surround stimulation delivered using HMD with four different moving pattern. Moving patterns consisted of close-far, superior-inferior lilting (pitch) , right-left tilting (roll) and horizontal rotation (yaw) movement. In all parameters, the test-retest reliability was high. Also, the construct validity of virtual moving surround stimulation was excellent (p<0.05). A posturographic balance assessment system equiped with virtual moving surround stimulation using HMD is considered clinically useful in evaluation of balance control in patients with brain injury.

  • PDF

Depth Controller Design for Submerged Body Moving near Free Surface Based on Adaptive Control (적응제어기법을 이용한 수면근처에서 운항하는 몰수체의 심도제어기 설계)

  • Park, Jong-Yong;Kim, Nakwan;Yoon, Hyeon Kyu;Kim, Su Yong;Cho, Hyeonjin
    • Journal of Ocean Engineering and Technology
    • /
    • v.29 no.3
    • /
    • pp.270-282
    • /
    • 2015
  • A submerged body moving near the free surface needs to maintain its attitude and position to accomplish missions. It is necessary to validate the performance of a designed controller before a sea trial. The hydrodynamic coefficients of maneuvering are generally obtained by experiments or computational fluid dynamics, but these coefficients have uncertainty. Environmental loads such as the wave exciting force and suction force act on the submerged body when it moves near the free surface. Thus, a controller for the submerged body should be robust to parameter uncertainty and environmental loads. In this paper, the six-degree-of-freedom equations of motions for the submerged body are constructed. The suction force is calculated using the double Rankine body method. An adaptive control method based on an artificial neural network and proportional-integral-derivative control are used for the depth controller. Simulations are performed under various depth and speed conditions, and the results show the effectiveness of the designed controller.