The Effects of Oil Entrained Air on the Dynamic Performance of a Hydraulically Driven Multibody System

Mohammadi, Manouchehr; Kiani-Oshtorjani, Mehran; Mikkola, Aki

doi:10.15866/iremos.v13i4.18612

Cited by 2 publications

(1 citation statement)

References 29 publications

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“…In Equation (9),

is the cross-sectional area of the pressure relief valve. Similarly, the volume flow rate

through a directional control valve can be computed as [ 67 , 68 ]

where

is the semi-empiric flow rate coefficient, and U is the relative position of the spool. Equation (10) is complemented by the following first-order differential equation:

where

is the reference voltage signal, and

is the time constant.…”

Section: Parameter Estimation Methodologymentioning

confidence: 99%

Estimating the Characteristic Curve of a Directional Control Valve in a Combined Multibody and Hydraulic System Using an Augmented Discrete Extended Kalman Filter

Khadim

Kiani-Oshtorjani

Jaiswal

et al. 2021

Sensors

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The estimation of the parameters of a simulation model such that the model’s behaviour matches closely with reality can be a cumbersome task. This is due to the fact that a number of model parameters cannot be directly measured, and such parameters might change during the course of operation in a real system. Friction between different machine components is one example of these parameters. This can be due to a number of reasons, such as wear. Nevertheless, if one is able to accurately define all necessary parameters, essential information about the performance of the system machinery can be acquired. This information can be, in turn, utilised for product-specific tuning or predictive maintenance. To estimate parameters, the augmented discrete extended Kalman filter with a curve fitting method can be used, as demonstrated in this paper. In this study, the proposed estimation algorithm is applied to estimate the characteristic curves of a directional control valve in a four-bar mechanism actuated by a fluid power system. The mechanism is modelled by using the double-step semi-recursive multibody formulation, whereas the fluid power system under study is modelled by employing the lumped fluid theory. In practise, the characteristic curves of a directional control valve is described by three to six data control points of a third-order B-spline curve in the augmented discrete extended Kalman filter. The results demonstrate that the highly non-linear unknown characteristic curves can be estimated by using the proposed parameter estimation algorithm. It is also demonstrated that the root mean square error associated with the estimation of the characteristic curve is 0.08% with respect to the real model. In addition, all the errors in the estimated states and parameters of the system are within the 95% confidence interval. The estimation of the characteristic curve in a hydraulic valve can provide essential information for performance monitoring and maintenance applications.

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“…In Equation (9),

is the cross-sectional area of the pressure relief valve. Similarly, the volume flow rate

through a directional control valve can be computed as [ 67 , 68 ]

where

is the semi-empiric flow rate coefficient, and U is the relative position of the spool. Equation (10) is complemented by the following first-order differential equation:

where

is the reference voltage signal, and

is the time constant.…”

Section: Parameter Estimation Methodologymentioning

confidence: 99%

Estimating the Characteristic Curve of a Directional Control Valve in a Combined Multibody and Hydraulic System Using an Augmented Discrete Extended Kalman Filter

Khadim

Kiani-Oshtorjani

Jaiswal

et al. 2021

Sensors

Self Cite

View full text Add to dashboard Cite

show abstract

Real-Time Simulation of Fluid Power Systems Containing Small Oil Volumes, Using the Method of Multiple Scales

et al. 2020

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Machinery devices often consist of mechanical mechanisms that are actuated by fluid power systems. In many applications, the mechanical system can be modelled and analysed in terms of the multibody system dynamics. Fluid power systems, in turn, can be analysed via the lumped-fluid theory, with which simulation of fluid power systems requires smaller integration time steps than needed by multi-body solvers. This leaves simulation of the entire machinery device beyond reach for a real-time framework, with the main reason for the very small time steps in modelling of fluid power systems being the presence of a small hydraulic volume, which creates a numerical stiffness problem. The stiffness issue may arise from numerical singularity emerging in the fluid power system, which implies that solving the governing equations involves different time scales-small and large. To resolve the numerical singularity in hydraulic circuits, the authors developed a perturbed model to alleviate the stiffness problem demonstrated that it can increase the integration time step by an order of magnitude. Since the perturbed model does necessitate a correction factor for the volumetric flow rate, the method of multiple scales is applied to compute the pressure within the small volume to second-order accuracy, O(ε 2), in comparison with the perturbed model's O(ε). The results reveal that if the correction parameter is not set, the perturbed model's cumulative error leads to considerable deviation in piston position with respect to the reference model, whereas the multiple-scale model eliminates the issue of cumulative error without demanding any flow-rate correction factor. INDEX TERMS fluid power system, real-time simulation, singular perturbed model, small volumes.

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The Effects of Oil Entrained Air on the Dynamic Performance of a Hydraulically Driven Multibody System

Cited by 2 publications

References 29 publications

Estimating the Characteristic Curve of a Directional Control Valve in a Combined Multibody and Hydraulic System Using an Augmented Discrete Extended Kalman Filter

Estimating the Characteristic Curve of a Directional Control Valve in a Combined Multibody and Hydraulic System Using an Augmented Discrete Extended Kalman Filter

Real-Time Simulation of Fluid Power Systems Containing Small Oil Volumes, Using the Method of Multiple Scales

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