• Title/Summary/Keyword: Ripples

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Method for Reduction of Pressure Ripples using the Parallel Pipeline in Fluid Pipeline (분지를 이용한 유압관로계의 압력맥동 저감 방안)

  • 이규원;장주섭;김경훈;윤영환
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.10a
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    • pp.299-302
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    • 1997
  • The pressure ripples are inevitabilitily generated by a fluctuation of flow rate caused pump mechanism, which occur noises, vibrations, and affect a control performance in tluid pipeline. The method for reduction of pressure ripples has been normally used a accumulator which is installed near the pump generating the pressure ripples. This paper introduces the parallel pipeline as a method to reduce pressure ripples in tluid pipeline, and confirms the usefulness of it in reducing the pressure ripples as compared with the fluid pipeline with a accumulator using AMESim(Advanced Modeling Environment for Simulations) Software.

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The Analytical Study on the Pressure Ripples in a Positive Displacement Vane Pump (유압 베인 펌프의 압력 맥동에 관한 연구)

  • 김기동;조명래;한동철;최상현
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1997.10a
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    • pp.225-231
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    • 1997
  • This paper reports on the theoretical study of the delivery pressure ripples of a positive displacement vane pump which is widely used for automobile power steering. Pressure ripples occur due to the flow tipples which induced cam ring profiles and reverse flow from the delivery ports. In this paper, the mathematical model for analyzing the pressure ripples has been presented, and set of the differential equationshave been solved using the Runge-Kutta method. As the results of analysis, instant ideal flow ripples, internal pressure, delivery pressure ripples, and delivery flow ripples have been presented. Internal pressure was related to delivery pressure variations, and amplitude of pressure tipples was increased with rotational speed and delivery pressure.

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Implementation of Thrust Ripple Reduction for a Permanent Magnet Linear Synchronous Motor Using an Adaptive Feed Forward Controller

  • Baratam, Arundhati;Karlapudy, Alice Mary;Munagala, Suryakalavathi
    • Journal of Power Electronics
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    • v.14 no.4
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    • pp.687-694
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    • 2014
  • This paper focuses on the analysis and compensation of thrust ripples in permanent magnet linear synchronous motors (PMLSM). The main drawback in PMLSMs is the presence of thrust ripples, which are mainly due to the interaction between the permanent magnets and armature slotted core. These thrust ripples reduce the performance of the drive system in high precision applications especially at low speeds. This paper analyzes thrust ripples using the discrete wavelet transform. These undesired thrust ripples are compensated by using an adaptive feed forward controller. It is observed that this novel controller reduces about 65 percent of the thrust ripples. An extensive simulation is performed through MATLAB and it is validated through experimental results using a d-SPACE system with a DS1104 control board.

REDUCTION OF PRESSURE RIPPLES USING A PARALLEL LINE IN HYDRAULIC PIPELINE

  • KIM K. H.;JANG J. S.;JUNG D. S.;KIM H. E.
    • International Journal of Automotive Technology
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    • v.6 no.1
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    • pp.65-70
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    • 2005
  • Pressure ripples, which are inevitably generated by a fluctuation of flow rate caused by a pump mechanism, include noises and vibrations in hydraulic pipeline. These noises and vibration deteriorate the stability and accuracy of hydraulic systems. The accumulator and hydraulic attenuator are normally used to reduce the pressure ripples. In this study, a parallel line is introduced to the hydraulic pipeline for the hydraulic system with a bent-axis piston pump as a method to reduce the pressure ripples. The dynamic characteristics of the hydraulic pipeline with a parallel line are analyzed by a transfer matrix in the frequency domain. The usefulness of the hydraulic pipeline with a parallel line was ascertained by experiment and simulation. The results from the experiment and simulation show that the hydraulic pipeline with a parallel line were effective in reducing the pressure ripples.

Flow and Pressure Ripple Characteristics of Hydrostatic Transmissions (유압전동장치의 유량 압력맥동 특성)

  • 김도태;윤인균
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.10 no.1
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    • pp.120-126
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    • 2001
  • This study deals with a flow and pressure ripple characteristics for a hydrostatic transmission(HST) consisting of a vari-able axial piston pump connected in an open loop to a fixed displacement axial piston motor. These flow ripples produced by pump and motor in HST interacts with the source impedances of the pump or motor and dynamic characteristics of the connected pipeline, and results in a pressure ripples, Pressure ripples. Pressure ripples in HSP is major source of vibration, which can lead to fatigue failure of components and cause noise. In this paper, the flow ripples generated by a swash plate type axial piston pump or motor in HST are measured by making use of hydraulic pipeline dynamics and the measured pressure data at two points along the pipeline. By using the self-checking functions, the validity of the method us investigated by comparison with the measured and estimated pressure ripples at the halfway section of the pipeline, and good agreement is achieved.

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A Study on the Discharge Pressure Ripple Characteristics of the Pressure Unbalanced Vane Pump (압력 비평형형 유압 베인 펌프의 토출 압력 맥동 특성 연구)

  • Jang, Joo-Sup
    • Journal of the Korean Society for Precision Engineering
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    • v.26 no.4
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    • pp.55-63
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    • 2009
  • This paper reports on the theoretical and experimental study of the pressure ripples in a pressure unbalanced type vane pump which have widespread use in industry. Because they can infinitely vary the volume of the fluid pumped in the system by a control. Pressure ripples occur due to the flow ripples induced by geometry of side plate, leakage flow, reverse flow from the outlet volume produced by pressure difference between pumping chamber and outlet volume when the pumping chamber connected with the outlet volume. In this paper, we measured the pressure variation of a pumping chamber, reaction force on a cam ring, the mathematical model for analyzing the pressure ripples which included vane detachment and fluid inertia effects in notch area has been presented, and was applied to predict the level and the wave form of the pressure ripples according to operating conditions.

A Study on the Reduction in Pressure Ripples for a Bent-Axis Piston Pump by a Phase Interference (위상간섭을 이용한 사축식 액셜 피스톤 펌프의 압력맥동 감소에 대한 연구)

  • 김경훈;최명진;이규원;장주섭
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.9
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    • pp.103-110
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    • 2004
  • Pressure ripples yield noise and vibration in hydraulic pipelines, which are inevitably generated by a fluctuation of flow rate in the pump mechanism, and such noise and vibration deteriorate the stability and accuracy of hydraulic systems. To reduce the pressure ripples, accumulator and hydraulic attenuator are normally used. In this study, parallel pipeline with a bent-axis piston pump is introduced to a hydraulic pipe system as a method for reducing the pressure ripples and using the transfer matrix method, the dynamic characteristics of the pipe system are analysed and compared with experimental results. The results show that the phase interference using parallel pipeline with a bent-axis piston pump is effective to reduce the pressure ripples in the hydraulic pipelines.

Automatic Velocity Ripple Compensation Algorithm by Feedforward Control (피드포워드를 이용한 속도리플 자동 보상 알고리즘)

  • Han, Ji Hee;Kim, Jung Han
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.9
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    • pp.951-959
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    • 2013
  • In order to improve the speed performance of the direct drive mechanical systems, a comprehensive analysis of the velocity ripples of blushless DC motors should be required. Every motor has a certain level of torque ripples when it generates power, and the generated torque ripple also makes the velocity ripples in the final output stage in speed control system. In this paper, a novel algorithm for reducing velocity ripples is proposed based on the modeling of torque ripples for BLDC motors. Various algorithms have been made for torque ripples, but usually they should be installed inside the amplifier logic, result in the difficulties of flexibility for various kinds of torque ripples. The proposed algorithm was developed for being ported in the controller not the amplifier, and it has the capability of the automatic compensation adjustment. The performance of the proposed algorithm was verified by effective simulations and experiments.

Current Variation Method for Reducing Torque Ripples of Linear Motor (선형 전동기의 상전류 조정을 통한 토크리플 저감법)

  • Kim, Min-Jae;Lim, Jae-Won;Jung, Hyun-Kyo
    • Proceedings of the KIEE Conference
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    • 2009.04b
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    • pp.85-87
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    • 2009
  • Linear motor is an energy conversion device which makes kinetic energy from electrical energy. This paper presents a method to reduce torque ripples by variation of the current. The torque ripples are basically caused by detent force so this method has a focus on reducing detent force. The torque ripples were calculated by finite element method.

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A Study on the Role of Notch and Radius Reduction Ratio in the Balanced Type Vane Pump (베인 펌프에서 노치와 반경 감소비의 역할에 관한 연구)

  • 김기동;조명래;한동철;최상현;문호지
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.1
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    • pp.87-93
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    • 1998
  • Pressure ripples of hydraulic vane pump results from flow ripples due to pump geometry and reverse flow through the discharge port due to compressibility of fluid and result in vibration and noise of connected hydraulic elements. In a balanced type vane pump, cam ring curve is important factor to influence the flow ripples. Therefore, to reduce the flow ripple, it has been required that optimal selection of seal region by proper design of cam ring and each port position, and notches for preventing the excessive reverse flow. This paper has been performed analytical study of compression characteristics with major design parameter in side plate and cam ring. and examined into the role of notch and radius reduction ratio.

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