• 제목/요약/키워드: External force

검색결과 1,320건 처리시간 0.024초

이중 EHA의 제어 특성 개선 (Control-performance Improvement of Dual EHAs)

  • 이성렬;홍예선
    • 드라이브 ㆍ 컨트롤
    • /
    • 제13권3호
    • /
    • pp.32-38
    • /
    • 2016
  • For this paper, the position-control performances of dual EHA(electro-hydrostatic actuator) systems were investigated according to two cases wherein the double-rod- and single-rod-type hydraulic cylinders were combined. Since the control performance is significantly dependent on the load conditions including external forces such as the inertia load, it is proposed here that the two sub-EHAs are driven by separate position and force controllers, instead of two identical position controllers. According to the simulation results, the best performance was achieved by the position-controlled single-rod-type EHA that was combined with a force-controlled double-rod-type EHA. As the force-controlled double-rod-type EHA compensated for the external loads on the position-controlled single-rod-type EHA, the position-control performance was not influenced by external forces including the inertia load. In addition, the position-controlled single-rod-type EHA contributed to the enhancement of the damping ratio by absorbing the pressure peaks through its internal accumulator. Due to the symmetrical piston areas, the double-rod-type EHA is more suitable for force control than the single-rod- type EHA.

비대칭 이중화 EHA의 동기 제어 (Synchronous Control of an Asymmetrical Dual Redundant EHA)

  • 이성렬;홍예선
    • 드라이브 ㆍ 컨트롤
    • /
    • 제13권2호
    • /
    • pp.1-9
    • /
    • 2016
  • In this paper, an elementary force fighting problem was investigated. The problem is encountered when a double-rod type EHA(electro-hydrostatic actuator) is combined with a single-rod type EHA to build a redundant actuator system with synchronized motion. When the rod-side chambers of the two different types of EHAs have the same effective piston areas and are simultaneously pressurized by an external load, the two EHAs behave identically, sharing the external load equally. However, when the piston head-side chamber of the single rod type EHA, having a larger effective area than the rod-side chamber, is pressurized by the external load, an abnormal force fighting between the two EHAs occurs, unless their pump speeds are properly decoupled. In this study, the output drive forces of each EHA were obtained from the cylinder pressure signals and applied to the position control for each EHA to maintain the balance between their pump speeds. Adding minor force difference feedback loops to the position control, the force fighting phenomena could be eliminated and steady state synchronization errors were reduced. The power consumption of the pumps also could be remarkably reduced, avoiding unnecessarily high load pressures to the pumps.

Chaotic Behavior in a Dynamic Love Model with Different External Forces

  • Bae, Youngchul
    • International Journal of Fuzzy Logic and Intelligent Systems
    • /
    • 제15권4호
    • /
    • pp.283-288
    • /
    • 2015
  • In this paper, we propose a dynamic mathematical model of love involving various external forces, in order to analyze the chaotic phenomena in a love model based on Romeo and Juliet. In addition, we investigate the nonlinear phenomena in a love model with external forces using time series and phase portraits. In order to describe nonlinear phenomena precisely using time series and phase portraits, we vary the type of external force, using models such as a sine wave, chopping wave, and square wave. We also apply various different parameters in the Romeo and Juliet model to acquire chaotic dynamics.

Welding deformation analysis based on improved equivalent strain method to cover external constraint during cooling stage

  • Kim, Tae-Jun;Jang, Beom-Seon;Kang, Sung-Wook
    • International Journal of Naval Architecture and Ocean Engineering
    • /
    • 제7권5호
    • /
    • pp.805-816
    • /
    • 2015
  • In the present study, external restraints imposed normal to the plate during the cooling stage were determined to be effective for reduction of the angular distortion of butt-welded or fillet-welded plate. A welding analysis model under external force during the cooling stage was idealized as a prismatic member subjected to pure bending. The external restraint was represented by vertical force on both sides of the work piece and bending stress forms in the transverse direction. The additional bending stress distribution across the plate thickness was reflected in the improved inherent strain model, and a set of inherent strain charts with different levels of bending stress were newly calculated. From an elastic linear FE analysis using the inherent strain values taken from the chart and comparing them with those from a 3D thermal elasto-plastic FE analysis, welding deformation can be calculated.

외부 후긴장 보강 과정의 합성보 거동에 대한 실험 및 해석적 연구 (The Experimental and Analytical Study on the Behavior of Composite Beam in the Processing of External Post Prestressing strengthen)

  • 박용걸;박영훈
    • 한국구조물진단유지관리공학회 논문집
    • /
    • 제5권4호
    • /
    • pp.147-153
    • /
    • 2001
  • The major objectives of this study are to investigate experimental and analytical behavior of composite steel plate strengthened by external post prestressing method and to study the increasing magnitude of load carrying capacity by the external post prestressing method. With installed strain gauges and LVDT, the change of structural behaviors according to the amount of prestressing force is measured and the effects of shear strengthening according to the degree of angle in tendon are studied. The analytical structural behavior according to the amount of prestressing force is also investigated using finite element method. The effectiveness of strengthening of external post prestressing method is proved and an efficient FEM model is suggested by comparing the test results and analyzing results.

  • PDF

슬래브교 외부 강선 보강용 정착구 개발 (Development of the Braket for External Prestressing Method in Slab Bridge)

  • 한만엽;이상열
    • 한국콘크리트학회:학술대회논문집
    • /
    • 한국콘크리트학회 2001년도 봄 학술발표회 논문집
    • /
    • pp.93-98
    • /
    • 2001
  • This study is to develop the end anchorage of external steel reinforcement of RC slab bridges. External prestress method using the existing steel is that When the anchorage is installed in slab end, a plenty of anchor bolts were required because the only tangential stress of anchor bolt received a tendon force. Then, for this reason, the wide end anchorage was required and the shape was complicate. But this reinforcement method using method that inserts anchor key at concrete surface cut a groove gets big internal force comparing to the anchorage using existing anchor bolt. Furthermore, the number of anchor bolt for installing apparently will be reduced, and the operation will be convenient because a small anchorage of a simple shape will be received a great tendon force

  • PDF

콘크리트 교량의 외부강선 보강을 위한 앵커키 정착장치의 개발 연구 (Development of the Bracket for External Prestressing Method for Slab Bridge)

  • 한만엽;이상열
    • 한국콘크리트학회:학술대회논문집
    • /
    • 한국콘크리트학회 2001년도 가을 학술발표회 논문집
    • /
    • pp.1009-1014
    • /
    • 2001
  • This study is to develop the end anchorage of external steel reinforcement of RC slab bridges. External prestress method using the existing steel is that When the anchorage is installed in slab end, a plenty of anchor bolts were required because the only tangential stress of anchor bolt received a tendon force. Then, for this reason, the wide end anchorage was required and the shape was complicate. But this reinforcement method using method that inserts anchor key at concrete surface cut a groove gets big internal force comparing to the anchorage using existing anchor bolt. Furthermore, the number of anchor bolt for installing apparently will be reduced, and the operation will be convenient because a small anchorage of a simple shape will be received a great tendon force.

  • PDF

주기적인 외력을 가진 Van der Pol 발진기에서의 비선형 거동 해석 (Analysis of Nonlinear Behavior in Fractional Van der Pol Equation with Periodic External Force)

  • 배영철
    • 한국전자통신학회논문지
    • /
    • 제11권1호
    • /
    • pp.87-92
    • /
    • 2016
  • Van der Pol 발진기는 비선형 제동 현상을 가진 비보존 발진기로서 높은 진폭에서의 에너지는 소산적이며 (dissipative)이고 낮은 진폭들에서는 생성되는 구조를 가진다. 본 논문에서는 Van Der Pol 발진기 모델에서 다른 거동을 확인하기 위하여 주기적 외력을 인가하고 여기에서 파라미터 변화에 따라 어떻게 리미트 사이클이 변화하는지에 대한 패턴을 확인하고자 한다.

사람 인식에 근접한 외력을 가진 사랑 모델에서 비선형 거동 분석 (Nonlinear Behavior Analysis in Love Model with closing awareness of Human)

  • 배영철
    • 한국전자통신학회논문지
    • /
    • 제12권1호
    • /
    • pp.201-208
    • /
    • 2017
  • 본 논문에서는 기본적인 로미오와 줄리엣의 사랑모델을 기반으로 외력을 가진 사랑 모델에서 외력을 사람의 인식에 기반한 모델을 만들기 위해 퍼지의 삼각 소속 함수를 제시한다. 또한 이 소속 함수를 외력으로 사용한 후 여기에서 나오는 거동 현상을 시계열과 위상 공간으로 나타내고, 비선형 특성이 존재하는지를 확인한다.

A GENERAL UNIQUENESS RESULT OF AN ENDEMIC STATE FOR AN EPIDEMIC MODEL WITH EXTERNAL FORCE OF INFECTION

  • Cha, Young-Joon
    • 대한수학회논문집
    • /
    • 제22권4호
    • /
    • pp.597-608
    • /
    • 2007
  • We present a general uniqueness result of an endemic state for an S-I-R model with external force of infection. We reduce the problem of finding non-trivial steady state solutions to that of finding zeros of a real function of one variable so that we can easily prove the uniqueness of an endemic state. We introduce an assumption which was usually used to show stability of a non-trivial steady state. It turns out that such an assumption adopted from a stability analysis is crucial for proving the uniqueness as well, and the assumption holds for almost all cases in our model.