Measured Dynamic Properties of Flexible Hoses

Johnston, D N; Way, Tim M.; Cone, Kerry

doi:10.1115/1.4000774

Cited by 8 publications

(5 citation statements)

References 6 publications

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“…The model is able to predict very rapid transients accurately, but it also requires knowledge of the material properties, which are sensitive to the temperature, pressure and curvature. Johnston et al also investigate the static and dynamic properties of a range of hoses, providing the necessary parameter values for modelling [26].…”

Section: Passive Tuned Flexible Hosesmentioning

confidence: 99%

Novel Integrated Active and Passive Control of Fluid-Borne Noise in Hydraulic Systems

Pan

Yuan

Ding

et al. 2021

Journal of Dynamic Systems, Measurement, and Control

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Fluid-borne noise (FBN) is a major contributor to structure-borne noise (SBN) and air-borne noise (ABN) in hydraulic fluid power systems and could lead to increased fatigue in system components. FBN is caused by the unsteady flow generated by pumps and motors and propagates through the system resulting in SBN and ABN. New hydraulic technologies such as digital switched hydraulic converters also generate unavoidable FBN. This article reports on a novel integrated FBN attenuation approach, which employs a hybrid control system by integrating an active feed forward noise attenuator with passive tuned flexible hoses. The active system which consists of adaptive notch filters using a variable step-size filtered-X Least Mean Squares algorithm is used to control a newly designed high-force high-bandwidth piezoelectric actuator in order to attenuate the dominant narrowband pressure ripples. The passive hose is tuned in the frequency domain and used to cancel the high-frequency pressure ripples. A time-domain hose model considering coupling of longitudinal wall and fluid waves was used to model the flexible hose in the integrated control system. Very good FBN cancellation was achieved by using the integrated control approach in simulation and experiments. It is an effective, cost-efficient and practical solution for FBN attenuation. The problem of high noise levels generated by hydraulically powered machines has risen significantly in awareness within industry and amongst the general public, and this work constitutes an important contribution to the sustainable development of low noise hydraulic fluid power machines.

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Section: Passive Tuned Flexible Hosesmentioning

confidence: 99%

Novel Integrated Active and Passive Control of Fluid-Borne Noise in Hydraulic Systems

Pan

Yuan

Ding

et al. 2021

Journal of Dynamic Systems, Measurement, and Control

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“…where β o is the fluid bulk modulus, β ho represents the dynamic hose bulk modulus, β hoSS is the static hose bulk modulus, and r β is the ratio β ho /β hoSS . According to [27], the hose bulk modulus changes during the system operation, i.e., dynamic bulk modulus (β ho ) is higher than static bulk modulus (β hoSS ) due to a phenomena called dynamic hardening. Those authors state that the r β is about 4 to 5 for nylon braid hoses, which is the case of the HVE hoses used in this paper.…”

Section: Selecting a Commercial Hydraulic Hosementioning

confidence: 99%

“…According to the experimental results presented in [27], the static hose bulk modulus can be expressed by:…”

Section: Selecting a Commercial Hydraulic Hosementioning

confidence: 99%

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Force Control of Hydraulic Actuators using Additional Hydraulic Compliance

Pérez¹,

Pieri²,

Negri³

2018

SV-JME

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This paper presents an approach for improving the performance of hydraulic force control systems by adding hydraulic compliance. Typically, force control systems require a flexible coupling system, such as a spring between the actuator and the load, to achieve a non-oscillatory response. To avoid the use of springs, this study proposes the use of special hoses to add compliance to the system hydraulically. With this approach, a direct connection between the actuator and the load is feasible, simplifying the mechanical assembly and saving physical space in the axial direction. An analytical model is proposed to estimate the appropriate hydraulic stiffness value and to select a commercial hose based on catalogue data. Moreover, a robust controller based on quantitative feedback theory is designed to improve the stability, performance and disturbance rejection of the force control system. The system performance is demonstrated by dynamic simulation and experimental results. Keywords: hydraulic force control, hydraulic compliance, high expansion volumetric hose, QFT-based control Highlights • A hydraulic force control system with added hydraulic compliance is presented. • Passive compliance is provided with the use of hydraulic hoses instead of mechanical springs. • An analytical procedure for selecting and sizing hydraulic hoses is proposed. • The presented achievements are validated by dynamic simulation and experimental results.

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“…Johnston and Edge 5 included frictional effects and extended the method to work with unequally spaced transducers. This is beneficial as some methods for measurement of flow ripple, impedance and transfer matrices 1,6–9 also require three unequally spaced pressure transducers, to avoid ill-conditioned equations when the transducers are spaced a multiple of a half-wavelength apart. Johnston and Edge’s method was adopted as one of two alternatives in ISO 15086-2:2000, 10 in which it is recommended to use ‘at any time when the speed of sound is to be measured under the effective working conditions in a system’, as it is well suited for in situ use under normal working flow and pressure conditions.…”

Section: Introductionmentioning

confidence: 99%

High-precision in situ measurement of speed of sound in hydraulic systems

Johnston

2019

Proceedings of the Institution of Mechanical Engineers, Part I:

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An existing ISO standard frequency-domain method for measurement of speed of sound in a hydraulic pipeline is enhanced and extended in this article to include in situ measurement of pressure transducer calibration factors. Transducer mounting stresses are shown to cause variations in the calibration factors, and the proposed method can be used to eliminate these uncertainties, consequently improving the accuracy of the speed of sound. 95% confidence ranges in the speed of sound of less than ±0.1% have been achieved, and such high precision cannot be achieved by other practical methods. The method can also been extended to estimate viscosity and mean flow velocity, but accuracy is less good. Novel time-domain versions of the method are introduced. These may be valuable for real-time monitoring, and changes in speed of sound or calibration factor can be tracked with minimal delay. Some examples showing the effect of sudden aeration are presented; a sudden drop in speed of sound is apparent.

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Measured Dynamic Properties of Flexible Hoses

Cited by 8 publications

References 6 publications

Novel Integrated Active and Passive Control of Fluid-Borne Noise in Hydraulic Systems

Novel Integrated Active and Passive Control of Fluid-Borne Noise in Hydraulic Systems

Force Control of Hydraulic Actuators using Additional Hydraulic Compliance

High-precision in situ measurement of speed of sound in hydraulic systems

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