The Challenge of Feedback in Fluid Power Tribotronic Control Systems

2020 ◽  
Author(s):  
Per Johansen ◽  
Nikolaj Grønkær ◽  
Andreas Langbak ◽  
Simon Krempin ◽  
Lasse Schmidt
Keyword(s):  
Control Systems ◽  
Simulation Models ◽  
Theoretical Work ◽  
Fluid Power ◽  
Measurement Technology ◽  
Control Loops ◽  
Modelling Analysis ◽  
Oil Whirl ◽  
Fluid Film Thickness

Abstract The hunt for increased efficiency and reliability of fluid power components have entailed a great deal of research on loss and wear mechanisms by means of computational tribology simulation in the last decades. The vast amount of theoretical work within tribology necessitates validation of the simulation models. The aim to validate such models has in recent years increased interest in sophisticated tribological measurement technology. A next level, for tribology in fluid power, is the integration of modelling, analysis and measurement technology with control to achieve active tribology, namely fluid power tribotronics. In this paper the challenge of feedback for tribotronic control loops in fluid power are addressed. Fundamental questions are in this regard to what extend do we need information? Is it necessary to measure fluid film thickness absolutely or dynamically, or do we even need in-situ information on the tribological joints? These questions are analysed in this paper by use of a dynamic lubricated journal-bearing model. From this analysis a conclusion on the oil whirl limit is found, which reveal an interesting perspective and potential risk in the application of feedforward in tribotronic control of lubricated journal-bearings. Finally, a discussion is concluded with the submission of relevant open research directions for fluid power tribotronic control systems.

State of the Art Review on Theoretical Tribology of Fluid Power Displacement Machines

2016 ◽  
Author(s):  
Remzija Ćerimagić ◽  
Per Johansen ◽  
Torben O. Andersen ◽  
Henrik C. Pedersen
Keyword(s):  
Wear Mechanisms ◽  
Interface Design ◽  
State Of The Art ◽  
Simulation Models ◽  
Theoretical Models ◽  
Theoretical Work ◽  
Fluid Power ◽  
Theoretical Approaches ◽  
Work Done ◽  
Efficiency And Reliability

Over the past 20 years an increasing focus on efficiency and reliability in fluid power displacement machines has provided an incentive to study loss and wear mechanisms. One example is the hydrostatic fluid power transmission systems for wind and wave energy applications. The loss and wear mechanisms are mainly attributed to the tribological interfaces in fluid power machines. Consequently, optimization of efficiency and reliability of fluid power machines imply consideration of tribological interface design. The majority of the work done by researchers and engineers on the study of loss and wear mechanisms in the lubricating gaps in fluid power machines is confined to simulation models, as experimental treatments of these mechanisms are very difficult. This means, that a complete verification of the theoretical work is difficult. The aim of this paper is a state of the art review on the theoretical work for the design and optimization of fluid power displacement machines, and also the work done to validate the theoretical models. This review is not a complete historical account, but aim to describe current trends in fluid power displacement machine tribology. The review considers the rheological models used in the theoretical approaches, the modeling of elastohydrodynamic effects, the modeling of thermal effects, and finally the experimental validation of the theoretical models.

Boosting the Capabilities of Gas Stand Data Acquisition and Control Systems by Using a Digital Twin Based on a Holistic Turbocharger Model

2021 ◽  
Author(s):  
José R. Serrano ◽  
Luis Miguel García-Cuevas ◽  
Vishnu Samala ◽  
Juan Antonio López-Carrillo ◽  
Holger Mai
Keyword(s):  
Data Acquisition ◽  
Control Systems ◽  
Heat Fluxes ◽  
Testing Time ◽  
Time Saving ◽  
Digital Twin ◽  
Dimensional Modeling ◽  
On Line ◽  
And Control

Abstract During the last decade, increasingly advanced turbocharger models have been developed for sizing, engine matching and one-dimensional modeling. This work goes further and, instead of using these models for turbocharged engines design or analysis, it implements them in the data acquisition and control system of a turbocharger gas stand. This way, interesting new capabilities arise. The paper shows that there are important synergies between advanced turbocharger gas stand data acquisition and control systems and the modern turbocharger holistic models that have not been deeply exploited until now. They can be summarized as: on-line heat fluxes analysis, in-situ outlier testing points detection, testing time saving and using digital-twin techniques to monitor turbocharger health during testing.

scholarly journals Simulating the Various Subsystems of a Coal Mine

2016 ◽  
Vol 6 (3) ◽  
pp. 993-999 ◽  
Author(s):  
V. Okolnishnikov ◽  
S. Rudometov ◽  
S. Zhuravlev
Keyword(s):  
Control Systems ◽  
Coal Mine ◽  
Simulation Models ◽  
Simulation System ◽  
Interactive Simulation ◽  
Coal Face ◽  
Visual Interactive Simulation ◽  
Process Control Systems ◽  
New Process ◽  
Actual Control

A set of simulation models of various subsystems of a coal mine was developed with the help of a new visual interactive simulation system of technological processes. This paper contains a brief description of this simulation system and its possibilities. The main possibilities provided by the simulation system are: the quick construction of models from library elements, 3D representation, and the communication of models with actual control systems. These simulation models were developed for the simulation of various subsystems of a coal mine: underground conveyor network subsystems, pumping subsystems and coal face subsystems. These simulation models were developed with the goal to be used as a quality and reliability assurance tool for new process control systems in coal mining.

scholarly journals Worst-Case Analysis of Digital Control Loops with Uncertain Input/Output Timing

10.29007/c4zl ◽  
2019 ◽  
Author(s):  
Maximilian Gaukler ◽  
Peter Ulbrich
Keyword(s):  
Control Systems ◽  
Digital Control ◽  
Worst Case Analysis ◽  
Real Time Systems ◽  
Input Output ◽  
Worst Case ◽  
Control Loops ◽  
Digital Control Systems ◽  
Uncertain Input ◽  
Time Systems

Benchmark Proposal: The implementation of digital control systems in complex multi- core or distributed real-time systems results in non-deterministic input/output timing. Such timing deviations typically lead to degraded performance or even instability, which in turn may jeopardize safety goals. We present the problem of proving worst-case guarantees for given input/output timing bounds as a benchmark for the verification of hybrid dynamical systems.

Design of Multi-Loop Modal Control Systems for Plants Having Complex Eigenvalues

1968 ◽  
Vol 1 (3) ◽  
pp. T61-T68 ◽  
Author(s):  
B. Porter ◽  
J. D. Carter
Keyword(s):  
Control Systems ◽  
Fourth Order ◽  
Design Procedure ◽  
Modal Control ◽  
The Real ◽  
Control Loops ◽  
Complex Eigenvalues ◽  
Oscillatory Response ◽  
Response Modes

In this paper a design procedure is developed which makes it possible to alter both the real and imaginary parts of any number of pairs of conjugate complex plant eigenvalues: this procedure alters one pair of conjugate eigenvalues at a time by the provision of a suitable pair of control loops. In this way, multi-variable linear plants can be designed so as to possess oscillatory response modes having any desired decrement and frequency. The procedure is illustrated by designing control loops for second- and fourth-order plants having matrices with conjugate complex eigenvalues.

Measurement and Numerical Simulation of the Velocity Profile in the Thin Film of an Impinging Water Jet

2021 ◽  
Vol 144 (3) ◽  
Author(s):  
Matthias Joppa ◽  
Mike Bermuske ◽  
Frank Rüdiger ◽  
Lars Büttner ◽  
Jochen Fröhlich ◽  
...  
Keyword(s):  
Velocity Profile ◽  
Simulation Model ◽  
Process Optimization ◽  
Low Cost ◽  
Simulation Models ◽  
Fluid Simulation ◽  
Doppler Velocity ◽  
Measurement Technology ◽  
Mean Velocity ◽  
Validation Data

Abstract Impinging circular free-surface water jets are used in challenging cooling and cleaning tasks. In order to develop simulation models for process optimization, validation data are required, which are currently not available. Therefore, the flow field of these jets is studied for the first time with the novel laser Doppler velocity profile sensor. The mean velocity field and fluctuations are measured within the stagnation and adjacent redirection region for radial coordinates up to three times the nozzle diameter. In the examined parameter range with jet velocities up to 17 m/s and nozzle diameters up to 5.2 mm, i.e., Reynolds numbers up to 69 500, thin films of a few hundred micrometers are formed, which hinder the measurement with common optical measuring systems. Based on the measurement results, a comparatively low-cost volume of fluid simulation model is developed and validated that presumes a relaminarized film flow. The profiles measured and the simulated flow show very good agreement. In the future, the simulation model provides a basis for process optimization and the innovative measurement technology used will prospectively provide further detailed insights into other flows with high velocity gradients.

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