• Title/Summary/Keyword: Force Method

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The Comparison of thrust computational methods of a brushless DC linear motor (브러시 없는 직류 선형 모터의 추력 계산 방법의 비교)

  • Choi, Moon-Suk;Kim, Yong-Yil
    • Proceedings of the KIEE Conference
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    • 1997.11a
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    • pp.32-34
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    • 1997
  • For a given brushless DC linear motor, we suggest the numerical prediction methods to analyze it's thrust characteristics. First, we calculate the magnetic flux density by the finite element method, and we then compute the maximum thrust with three computational methods - a Lorentz equation, a Maxwell stress method and a virtual work method. To confirm the accuracy of the computational methods, we measure the thrust of the linear motor made by our laboratory with a force-torque sensor. Also, we calculate the thrust by the measured back electromotive force. To choose the appropriate method for a specified application, we compare the maximum thrusts of the computational method and the calculation by the back electromotive force with the measured one. We conclude that the Maxwell stress method is turned out the best because it has the most accurate results among three computational methods and it is more convenient than the calculation method by the back electromotive force.

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Simultaneous analysis, design and optimization of trusses via force method

  • Kaveh, A.;Bijari, Sh.
    • Structural Engineering and Mechanics
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    • v.65 no.3
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    • pp.233-241
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    • 2018
  • In this paper, the Colliding Bodies Optimization (CBO), Enhanced Colliding Bodies Optimization (ECBO) and Vibrating Particles System (VPS) algorithms and the force method are used for the simultaneous analysis and design of truss structures. The presented technique is applied to the design and analysis of some planer and spatial trusses. An efficient method is introduced using the CBO, ECBO and VPS to design trusses having members of prescribed stress ratios. Finally, the minimum weight design of truss structures is formulated using the CBO, ECBO and VPS algorithms and applied to some benchmark problems from literature. These problems have been designed by using displacement method as analyzer, and here these are solved for the first time using the force method. The accuracy and efficiency of the presented method is examined by comparing the resulting design parameters and structural weight with those of other existing methods.

Design Optimization and Development of Linear Brushless Permanent Magnet Motor

  • Chung, Myung-Jin;Gweon, Dae-Gab
    • International Journal of Control, Automation, and Systems
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    • v.1 no.3
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    • pp.351-357
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    • 2003
  • A method of design optimization for minimization of force ripple and maximization of thrust force in a linear brushless permanent magnet motor without finite element analysis is represented. The design optimization method calculated the driving force in the function of electric and geometric parameters of a linear brushless PM motor using the sequential quadratic programming method. Using electric and geometric parameters obtained by this method, the normalized force ripple is reduced 7.7% (9.7% to 2.0%) and the thrust force is increased 12.88N (111.55N to 124.43N) compared to those not using design optimization.

Dynamic Analysis of Multibody Systems Undertaking Impulsive Force using Kane's Method (충격하중을 받는 시스템의 케인 방법을 이용한 다물체 동역학 해석)

  • 김상국;박정훈;유홍희
    • Transactions of the Korean Society of Automotive Engineers
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    • v.6 no.3
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    • pp.169-176
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    • 1998
  • A method for the dynamic analysis of multibody systems undertaking impulsive force is introduced in this paper. A partial velocity matrix based on Kane's method is introduced to reduce the number of equations to be solved. Only minimum number of equations of motion can be obtained by using the partial velocity matrix. This reduces the computational effort significantly to obtain the dynamic response of the system. At the very moment of the impulse, instead of using the numerical integrator to solve the equations of motion, the impulse and momentum principle is used to obtain the dynamic response. The impulse as wall as the reaction force acting on the kinematic joints can easily calculated too.

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Design of Measurement System and Thrust Force Analysis Method for HB-Type Linear Pulse Motor (HB형 선형 펄스모터의 추력 계산법의 비교 및 측정장치 설계)

  • Bae D.K.;Kim K.H.;Park H.S.
    • Proceedings of the KIPE Conference
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    • 2003.07a
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    • pp.141-145
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    • 2003
  • The linear motor available for linear transition motion, because of its advantages, the motor design and its application have gradually increased, but the quantitative measurement system of thrust force has not been generalized. So, this paper proposes the modeling, computation method, and measurement system of linear thrust force in HB-type linear pulse motor. As the computation method of thrust force in linear motor is presented and the measurement system is designed, and manufactured, it would be verified that reliability of measurement method and measurement system, considering on and comparing the results of mathematical modeling with measured values of static thrust force and dynamic one.

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A large surface-shape measurement method by using Atomic Force Microscope (원자간력 현미경을 이용한 대면적 표면 형상 측정 방법)

  • Shin Y.H.;Ko M.J.;Hong S.W.;Kwon H.K.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.1543-1546
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    • 2005
  • This paper presents a method to measure a large surface shape using atomic force microscopy, which has been used mostly for measuring over very tiny surfaces. Experiments are performed to measure a step height and a slope of a test sample. The proposed method is rigorously compared with the coordinate measuring machine. The repetition accuracy and the effects of the set point are also studied. The experimental results show that the proposed method is reliable and should be effective to measure both the nano-accuracy surface profile as well as the micro-accuracy global shape of a macro/micro parts using atomic force microscope.

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Force Arrow: An Efficient Pseudo-Weight Perception Method

  • Lee, Jun
    • Journal of the Korea Society of Computer and Information
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    • v.23 no.7
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    • pp.49-56
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    • 2018
  • Virtual object weight perception is an important topic, as it heightens the believability of object manipulation in immersive virtual environments. Although weight perception can be achieved using haptic interfaces, their technical complexity makes them difficult to apply in immersive virtual environments. In this study, we present a visual pseudo-haptic feedback system that simulates and depicts the weights of virtual objects, the effect of which is weight perception. The proposed method recognizes grasping and manipulating hand motions using computer vision-based tracking methods, visualizing a Force Arrow to indicate the current lifting forces and its difference from the standard lifting force. With the proposed Force Arrow method, a user can more accurately perceive the logical and unidirectional weight and therefore control the force used to lift a virtual object. In this paper, we investigate the potential of the proposed method in discriminating between different weights of virtual objects.

Uncertainty Evaluation of a Multi-axis Force/Moment Sensor and Its Application (다축 힘/모멘트센서의 불확도평가 및 응용에 관한 연구)

  • 김갑순
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.177-180
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    • 2001
  • This paper describes the calibration method and the evaluation method of relative expanded uncertainty for a multi-axis force/moment sensor. This sensor should be calibrated to be use in the industry. Now, the confidence of the calibration result is expressed with interference error. But it is no inaccurate, because an interference error, besides, a reproducibility error of the sensor, a error of this six-axis force/moment sensor calibrator, and so on. Thus, in order to accurately evaluate the relative expanded uncertainty of it, the concept of the uncertainty should be induced, and these errors must be contained in the relative expanded uncertainty. In this paper, the calibration method is exhibited and the evaluation method of the relative expanded uncertainty is also exhibited. And, a six-axis force/moment sensor was calibrated and the relative expanded uncertainty was evaluated.

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Force/Torque Control of Ultrasonic Motor with PWM Driving Method (PWM 구동방식을 이용한 초음파 모터의 힘/ 토크제어)

  • 최병현;최혁렬
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.11
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    • pp.2723-2731
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    • 2000
  • Ultrasonic motors(USM) has been emerging as one type actuators, which possess many advantages such as high torque, low weight, compact size and no magnetic field generation. In spite of these features, there are several problems to be solved, which are temperature rise in case of long term operation, non -linearity, and hysteresis. Among these, hysteresis cause the most serious problem in force/torque control applications. To cope with this paper we propose a new PWM driving method which can be applied to force/torque control applications. To cope with this problem, in this paper we propose a new PWM driving method which can applied to force/torque control of USM. To verify the proposed method, an experimental setup was built and several experiments were performed.

Simplified equations for Vierendeel design calculations of composite beams with web openings

  • Panedpojaman, Pattamad
    • Steel and Composite Structures
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    • v.27 no.4
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    • pp.401-416
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    • 2018
  • Composite beams with web openings are vulnerable to Vierendeel bending failure. The available methods provide quite conservative estimates of Vierendeel bending resistance. An alternative design method to compute the resistance was proposed in this study, based on quadratic nonlinear interactions of normalized shear force, axial force and Vierendeel bending moment. The interactions of the top and bottom Tee section must satisfy mutual conditions to prevent the Vierendeel failure. The normalized shear force and Vierendeel bending moment of the composite part were used instead in the top Tee interaction. The top Tee axial force was computed based on force equilibrium. Based on a rigid-plastic model, the composite resistance is estimated using an effective slab width of the vertical shear resistance. On using the proposed method, nonlinear reductions due to shear loads and axial forces are not required, in contrast to prior methods. The proposed method was validated against experiments from literature. The method limitations and accuracy as well as the Vierendeel behavior were investigated by finite element simulations, with varied composite beam parameters. The proposed design loads are less conservative than earlier estimates and deviate less from the simulations.