Pub Date : 2018-07-01DOI: 10.1109/GFPS.2018.8472372
Washington Fernandes de Souza, E. Rafikova, M. Meza, S. Gafurov
This paper represents the implementation of a control technique known as Backstepping for solution of the problem of trajectory tracking of an underactuated Hovercraft. The Hovercraft is a vehicle sustained by air cushion in its base, so it doesn’t have contact with the soil. The Hovercraft can move around over a solid or aquatic surface. The desired trajectory is presented as a virtual vehicle with the same dynamics as the actual one. The control methodology uses Backstepping to design the virtual velocity controls to globally asymptotically stabilize the positions at the origin. Controls for the torques also was designed the velocities of the vehicles. Numerical simulations were performed in order to demonstrate the effectiveness of the developed control design. This demonstration was done by means of the comparison of the reference trajectory and obtained theoretically. The considered Hovercraft converges to the reference trajectory for near initial conditions as well as for distant initial conditions. It results in a good performance of the proposed control strategy to solve the problem of trajectory tracking of an underactuated Hovercraft. In addition, the accommodation time was obtained to be smaller in exchange for an increase of the effort control due to increase of the gain of the controller.
{"title":"Backstepping Trajectory Tracking of Underactuated Hovercraft","authors":"Washington Fernandes de Souza, E. Rafikova, M. Meza, S. Gafurov","doi":"10.1109/GFPS.2018.8472372","DOIUrl":"https://doi.org/10.1109/GFPS.2018.8472372","url":null,"abstract":"This paper represents the implementation of a control technique known as Backstepping for solution of the problem of trajectory tracking of an underactuated Hovercraft. The Hovercraft is a vehicle sustained by air cushion in its base, so it doesn’t have contact with the soil. The Hovercraft can move around over a solid or aquatic surface. The desired trajectory is presented as a virtual vehicle with the same dynamics as the actual one. The control methodology uses Backstepping to design the virtual velocity controls to globally asymptotically stabilize the positions at the origin. Controls for the torques also was designed the velocities of the vehicles. Numerical simulations were performed in order to demonstrate the effectiveness of the developed control design. This demonstration was done by means of the comparison of the reference trajectory and obtained theoretically. The considered Hovercraft converges to the reference trajectory for near initial conditions as well as for distant initial conditions. It results in a good performance of the proposed control strategy to solve the problem of trajectory tracking of an underactuated Hovercraft. In addition, the accommodation time was obtained to be smaller in exchange for an increase of the effort control due to increase of the gain of the controller.","PeriodicalId":273799,"journal":{"name":"2018 Global Fluid Power Society PhD Symposium (GFPS)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125419126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-07-01DOI: 10.1109/GFPS.2018.8472383
R. Badykov, S. Falaleev, H. Wood, A. Vinogradov
This paper provides a numerical technique to determine the dynamic characteristics of a gas film inside a dry gas seal gap based on steady-state and transient CFD calculations. Two dry gas seals with spiral grooves were studied. Steady-state calculation results were compared with the experimental data. The transient dry gas seal model was created to obtain the dynamic characteristics of a gas film. This model is able to take into account the mutual influence of stator and rotor rings on a gas film. This is made by adding the mesh deformation within very small range (from 2 to 10 microns) along with adding for the mesh the ability to move freely within a big range (up to 500 microns). FSI simulation was added to solve Reynolds- averaged Navier-Stokes equations and dynamic equations of rigid body motion together. Using steady-state and transient gas film models, dynamic and static opening forces were obtained for the different gap values. Gas film stiffness was calculated. In order to determine the oscillation frequency of a gas film, Fourier transform was applied.
本文提出了一种基于稳态和瞬态CFD计算来确定干气密封间隙内气膜动态特性的数值方法。对两种带螺旋槽的干气密封进行了研究。将稳态计算结果与实验数据进行了比较。为了获得气膜的动态特性，建立了瞬态干气密封模型。该模型能够考虑定子环和转子环对气膜的相互影响。这是通过在非常小的范围内(从2到10微米)添加网格变形以及在大范围内(高达500微米)添加网格自由移动的能力来实现的。在求解刚体运动动力学方程和Reynolds- average Navier-Stokes方程时，加入了FSI仿真。利用稳态和瞬态气膜模型，得到了不同间隙值下的动、静态开启力。计算气膜刚度。为了确定气膜的振荡频率，应用傅里叶变换。
{"title":"Gas film vibration inside dry gas seal gap","authors":"R. Badykov, S. Falaleev, H. Wood, A. Vinogradov","doi":"10.1109/GFPS.2018.8472383","DOIUrl":"https://doi.org/10.1109/GFPS.2018.8472383","url":null,"abstract":"This paper provides a numerical technique to determine the dynamic characteristics of a gas film inside a dry gas seal gap based on steady-state and transient CFD calculations. Two dry gas seals with spiral grooves were studied. Steady-state calculation results were compared with the experimental data. The transient dry gas seal model was created to obtain the dynamic characteristics of a gas film. This model is able to take into account the mutual influence of stator and rotor rings on a gas film. This is made by adding the mesh deformation within very small range (from 2 to 10 microns) along with adding for the mesh the ability to move freely within a big range (up to 500 microns). FSI simulation was added to solve Reynolds- averaged Navier-Stokes equations and dynamic equations of rigid body motion together. Using steady-state and transient gas film models, dynamic and static opening forces were obtained for the different gap values. Gas film stiffness was calculated. In order to determine the oscillation frequency of a gas film, Fourier transform was applied.","PeriodicalId":273799,"journal":{"name":"2018 Global Fluid Power Society PhD Symposium (GFPS)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130390972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-07-01DOI: 10.1109/GFPS.2018.8472397
F. Paltrinieri, M. Milani, L. Montorsi, Stefano Terzi
In this paper the main design features of an innovative combined hydraulic valve for high-pressure washing applications have been investigated by means of numerical modelling and experimental testing. This particular type of hydraulic component is obtained joining together a relief and a bypass valve. When the washing system is activated, the relief valve limits the maximum admitted working pressure while, when the washing system is switched off, the bypass valve unloads the hydraulic circuit and a direct connection with the drain ambient is quickly established. First of all, a very detailed lumped and distributed numerical model of the combined valve has been developed, with particular care devoted to the coupling between all the mechanical internal components (piston with holes, bushing and related springs) and to the valve body inner hydraulic connections. Then, the predictive capability of this lumped and distributed numerical model has been verified by means of a numerical versus experimental comparison, performed for a wide range of operating conditions (inlet pressure and volumetric flow rate) and geometrical parameters (sealing gaps, springs' stiffness and nozzle size). Finally, the previously validated numerical model has been applied in order to identify reliable design solutions for typical washing conditions, characterized by fluid pressure values spanning in the range between 50 to 280 bar and inlet volumetric flow rates comprised between 10 and 40 l/min.
{"title":"Modelling and Testing an Innovative Combined Hydraulic Valve for High-Pressure Washing","authors":"F. Paltrinieri, M. Milani, L. Montorsi, Stefano Terzi","doi":"10.1109/GFPS.2018.8472397","DOIUrl":"https://doi.org/10.1109/GFPS.2018.8472397","url":null,"abstract":"In this paper the main design features of an innovative combined hydraulic valve for high-pressure washing applications have been investigated by means of numerical modelling and experimental testing. This particular type of hydraulic component is obtained joining together a relief and a bypass valve. When the washing system is activated, the relief valve limits the maximum admitted working pressure while, when the washing system is switched off, the bypass valve unloads the hydraulic circuit and a direct connection with the drain ambient is quickly established. First of all, a very detailed lumped and distributed numerical model of the combined valve has been developed, with particular care devoted to the coupling between all the mechanical internal components (piston with holes, bushing and related springs) and to the valve body inner hydraulic connections. Then, the predictive capability of this lumped and distributed numerical model has been verified by means of a numerical versus experimental comparison, performed for a wide range of operating conditions (inlet pressure and volumetric flow rate) and geometrical parameters (sealing gaps, springs' stiffness and nozzle size). Finally, the previously validated numerical model has been applied in order to identify reliable design solutions for typical washing conditions, characterized by fluid pressure values spanning in the range between 50 to 280 bar and inlet volumetric flow rates comprised between 10 and 40 l/min.","PeriodicalId":273799,"journal":{"name":"2018 Global Fluid Power Society PhD Symposium (GFPS)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130025089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-07-01DOI: 10.1109/GFPS.2018.8472376
Remzija Ćerimagić, P. Johansen, T. Andersen
In recent times the radial piston principle has been found particularly suitable for hydrostatic fluid power transmission systems for renewable energy applications. This forms an incentive to design these units for high efficiency. At present only little work has been dedicated to modeling of losses in radial piston units. The focus of this paper is an isogeometric tribodynamics model of a radial piston fluid power motor, which connects the rigid body dynamics with the models of hydrodynamic lubrication pressure in the sliding parts. The use of CAD models in the formulation of the tribodynamics eliminates the time and effort needed to manually parameterize the interface geometry. A NURBS-based isogeometric analysis approach is considered for the modeling of pressure dynamics of the fluid film lubrication. Isogeometric analysis is considered superior in terms of accuracy and efficiency compared to standard finite element methods, as it needs lesser degrees of freedom to produce same order of error. Moreover, it renders an exact representation of the lubrication domains in fluid power machinery possible. This makes isogeometric analysis very much convenient for boundary value problems on surfaces, such as hydrodynamic lubrication in joint clearances of fluid power machines. The paper explains the isogeometric tribodynamics model structure and gives a detailed description of the modeling of the piston-cylinder interface of a Calzoni type radial piston motor using the isogeometric approach.
{"title":"Isogeometric Tribodynamics of a Radial Piston Fluid Power Motor","authors":"Remzija Ćerimagić, P. Johansen, T. Andersen","doi":"10.1109/GFPS.2018.8472376","DOIUrl":"https://doi.org/10.1109/GFPS.2018.8472376","url":null,"abstract":"In recent times the radial piston principle has been found particularly suitable for hydrostatic fluid power transmission systems for renewable energy applications. This forms an incentive to design these units for high efficiency. At present only little work has been dedicated to modeling of losses in radial piston units. The focus of this paper is an isogeometric tribodynamics model of a radial piston fluid power motor, which connects the rigid body dynamics with the models of hydrodynamic lubrication pressure in the sliding parts. The use of CAD models in the formulation of the tribodynamics eliminates the time and effort needed to manually parameterize the interface geometry. A NURBS-based isogeometric analysis approach is considered for the modeling of pressure dynamics of the fluid film lubrication. Isogeometric analysis is considered superior in terms of accuracy and efficiency compared to standard finite element methods, as it needs lesser degrees of freedom to produce same order of error. Moreover, it renders an exact representation of the lubrication domains in fluid power machinery possible. This makes isogeometric analysis very much convenient for boundary value problems on surfaces, such as hydrodynamic lubrication in joint clearances of fluid power machines. The paper explains the isogeometric tribodynamics model structure and gives a detailed description of the modeling of the piston-cylinder interface of a Calzoni type radial piston motor using the isogeometric approach.","PeriodicalId":273799,"journal":{"name":"2018 Global Fluid Power Society PhD Symposium (GFPS)","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131137063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-07-01DOI: 10.1109/GFPS.2018.8472395
Stefano Terzi, M. Milani, L. Montorsi, B. Manhartsgruber
The paper investigates the multiphase flow through the plates of multi plate wet-clutches for hydro- mechanical variable transmission in order to address the performance of the lubricating systems and its influence on the thermo-mechanical stresses on the plates. The lubricating oil distribution is very difficult to measure experimentally on a real geometry, therefore, a numerical model for the prediction of the flow distribution within the clutch plates is proposed. The volume of fluid approach is used to model the multi-phase flow that characterizes the component and a modular approach is defined to reproduce accurately the real geometry. Furthermore, the numerical modeling is validated against measurements carried out on an ad-hoc designed test rig. The testing facility replicates both the geometry of a real clutch and the actual operating conditions. Transparent PMMA components and fast imaging techniques are used to capture the multiphase flow pattern within the gear distributor chamber, while a 3D printed component and a specific collector system have been designed in order to reproduce the disks position and measure the oil distribution through the plates’ clearances by varying the working conditions. A good agreement between the numerical and the experimental results was found and the analysis highlighted the importance of modeling the multi-phase nature of the lubrication process for the accurate prediction of the oil distribution within multi plate wet-clutches.)
{"title":"Experimental and numerical analysis of the multiphase flow distribution in multi plate wetclutches for HVT transmissions under actual operating conditions","authors":"Stefano Terzi, M. Milani, L. Montorsi, B. Manhartsgruber","doi":"10.1109/GFPS.2018.8472395","DOIUrl":"https://doi.org/10.1109/GFPS.2018.8472395","url":null,"abstract":"The paper investigates the multiphase flow through the plates of multi plate wet-clutches for hydro- mechanical variable transmission in order to address the performance of the lubricating systems and its influence on the thermo-mechanical stresses on the plates. The lubricating oil distribution is very difficult to measure experimentally on a real geometry, therefore, a numerical model for the prediction of the flow distribution within the clutch plates is proposed. The volume of fluid approach is used to model the multi-phase flow that characterizes the component and a modular approach is defined to reproduce accurately the real geometry. Furthermore, the numerical modeling is validated against measurements carried out on an ad-hoc designed test rig. The testing facility replicates both the geometry of a real clutch and the actual operating conditions. Transparent PMMA components and fast imaging techniques are used to capture the multiphase flow pattern within the gear distributor chamber, while a 3D printed component and a specific collector system have been designed in order to reproduce the disks position and measure the oil distribution through the plates’ clearances by varying the working conditions. A good agreement between the numerical and the experimental results was found and the analysis highlighted the importance of modeling the multi-phase nature of the lubrication process for the accurate prediction of the oil distribution within multi plate wet-clutches.)","PeriodicalId":273799,"journal":{"name":"2018 Global Fluid Power Society PhD Symposium (GFPS)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114805830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-07-01DOI: 10.1109/GFPS.2018.8472358
Rituraj, Thomas Ransegnola, A. Vacca
External gear machines (EGMs) are used in a variety of industries ranging from fluid power machinery to fluid transport system and fuel injection applications. To gain understanding of the performance and dynamic characteristics of operation of these units, several simulation tools have been developed in past. Some of these tools are based on lumped parameter approaches, which are useful for fast design studies and optimizations. However, most of these models are based on “a priori” assumptions, particularly as concerns the flow regime of the leakage flows. Internal leakages not only determine the volumetric efficiency of an EGM, they also affect the actual pressure loading on the gears. A simple Iaminar flow assumption is usually considered for the leakage flow at the tooth tip of the gears, but as this paper will show, for certain EGMs this hypothesis is not valid, and effects of turbulence at the tooth tip are observed. The goal of this paper is to propose a methodology for fast lumped parameter approaches to model the tooth tip leakage flow in EGMs, applicable for a broad range of operating conditions. The proposed model considers the occurrence of turbulent flow conditions as well as the entrance pressure drop, with considerations based on existing published work and CFD simulations. In order to show realistic simulation, the proposed model is implemented within the HYdraulic GEar machines Simulator (HYGESim), developed by the authors’ team over the past years. The proposed model is then used to study the tooth space volume pressurization and leakage flow on a reference pump working with Jet A-l fuel, showing the importance of the proposed modeling approach.
{"title":"An Investigation on the Leakage Flow and Instantaneous Tooth Space Pressure in External Gear Machines","authors":"Rituraj, Thomas Ransegnola, A. Vacca","doi":"10.1109/GFPS.2018.8472358","DOIUrl":"https://doi.org/10.1109/GFPS.2018.8472358","url":null,"abstract":"External gear machines (EGMs) are used in a variety of industries ranging from fluid power machinery to fluid transport system and fuel injection applications. To gain understanding of the performance and dynamic characteristics of operation of these units, several simulation tools have been developed in past. Some of these tools are based on lumped parameter approaches, which are useful for fast design studies and optimizations. However, most of these models are based on “a priori” assumptions, particularly as concerns the flow regime of the leakage flows. Internal leakages not only determine the volumetric efficiency of an EGM, they also affect the actual pressure loading on the gears. A simple Iaminar flow assumption is usually considered for the leakage flow at the tooth tip of the gears, but as this paper will show, for certain EGMs this hypothesis is not valid, and effects of turbulence at the tooth tip are observed. The goal of this paper is to propose a methodology for fast lumped parameter approaches to model the tooth tip leakage flow in EGMs, applicable for a broad range of operating conditions. The proposed model considers the occurrence of turbulent flow conditions as well as the entrance pressure drop, with considerations based on existing published work and CFD simulations. In order to show realistic simulation, the proposed model is implemented within the HYdraulic GEar machines Simulator (HYGESim), developed by the authors’ team over the past years. The proposed model is then used to study the tooth space volume pressurization and leakage flow on a reference pump working with Jet A-l fuel, showing the importance of the proposed modeling approach.","PeriodicalId":273799,"journal":{"name":"2018 Global Fluid Power Society PhD Symposium (GFPS)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122086625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-07-01DOI: 10.1109/GFPS.2018.8472399
N. C. Bender, H. Pedersen, B. Winkler, Andreas Plöckinger
This paper presents a framework to evaluate different power losses in regards to hydraulic valves used in Digital Displacement® Units (DDU). The feasibility of DDU may be compromised if internal leakage in the hydraulic valves develops over time, introduction of a time-dimension is the objective of this work. The actual leakage that will develop over time due to mechanical wear is unknown, which is the main reason why previous work has not addressed this research topic. The underlying assumption of the developed framework is that internal leakage propagates as a consequence of the amount of valve switching cycles. This assumption is combined with physical knowledge about a DDU into one theoretical framework, which is defined both as non-linear differential equations and as a timeaveraged static model to visualize the difference in accuracy when put into context of a specific machine. Thereby reducing the required simulation time and enhancing design possibilities. The main contribution of this work is a revision of the conventional efficiency curve of a DDU, where it now includes a novel trade-off between averaged displacement and efficiency (without partial strokes). Over a period of 25 years an average displacement of 55%. is shown to be optimal from an energy perspective.
{"title":"Evaluating the Influence of Leaking Active Check Valves in Digital Displacement® Units","authors":"N. C. Bender, H. Pedersen, B. Winkler, Andreas Plöckinger","doi":"10.1109/GFPS.2018.8472399","DOIUrl":"https://doi.org/10.1109/GFPS.2018.8472399","url":null,"abstract":"This paper presents a framework to evaluate different power losses in regards to hydraulic valves used in Digital Displacement® Units (DDU). The feasibility of DDU may be compromised if internal leakage in the hydraulic valves develops over time, introduction of a time-dimension is the objective of this work. The actual leakage that will develop over time due to mechanical wear is unknown, which is the main reason why previous work has not addressed this research topic. The underlying assumption of the developed framework is that internal leakage propagates as a consequence of the amount of valve switching cycles. This assumption is combined with physical knowledge about a DDU into one theoretical framework, which is defined both as non-linear differential equations and as a timeaveraged static model to visualize the difference in accuracy when put into context of a specific machine. Thereby reducing the required simulation time and enhancing design possibilities. The main contribution of this work is a revision of the conventional efficiency curve of a DDU, where it now includes a novel trade-off between averaged displacement and efficiency (without partial strokes). Over a period of 25 years an average displacement of 55%. is shown to be optimal from an energy perspective.","PeriodicalId":273799,"journal":{"name":"2018 Global Fluid Power Society PhD Symposium (GFPS)","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128603143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-07-01DOI: 10.1109/GFPS.2018.8472400
Samuel Kätnell, A. Dell’Amico, Liselott Ericson
Digital hydraulic piston pumps that use electrically controlled on/off valves to individually control the flow from each piston is a promising technique as these pumps are highly efficient at part displacement and respond quickly. However, digital pumps can still use check valves on the inlet, a fact that makes analysing wobble plate pumps (WPP) and their check valves interesting. Here, we measured the cylinder pressures of a WPP and compared these results with results from a simulation model we developed. In addition, we used linear analysis to investigate how different design parameters affect the valve’’s behaviour. From the measurements we found that the cylinder pressure is clearly affected the flow from other pistons and also that the system is not as stiff as expected. From the linear analysis, a criterion of how to design the valve to avoid instability was derived.
{"title":"Simulation and validation of a wobble plate pump with a focus on check valve dynamics","authors":"Samuel Kätnell, A. Dell’Amico, Liselott Ericson","doi":"10.1109/GFPS.2018.8472400","DOIUrl":"https://doi.org/10.1109/GFPS.2018.8472400","url":null,"abstract":"Digital hydraulic piston pumps that use electrically controlled on/off valves to individually control the flow from each piston is a promising technique as these pumps are highly efficient at part displacement and respond quickly. However, digital pumps can still use check valves on the inlet, a fact that makes analysing wobble plate pumps (WPP) and their check valves interesting. Here, we measured the cylinder pressures of a WPP and compared these results with results from a simulation model we developed. In addition, we used linear analysis to investigate how different design parameters affect the valve’’s behaviour. From the measurements we found that the cylinder pressure is clearly affected the flow from other pistons and also that the system is not as stiff as expected. From the linear analysis, a criterion of how to design the valve to avoid instability was derived.","PeriodicalId":273799,"journal":{"name":"2018 Global Fluid Power Society PhD Symposium (GFPS)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127441289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-07-01DOI: 10.1109/GFPS.2018.8472363
V. Donkov, T. Andersen, H. Pedersen, M. Ebbesen
In this paper, two Discrete Displacement Cylinders (DDCs) are used to drive the boom of a knuckle boom crane. DDCs operate by connecting one of several available pressure levels to each chamber in order to produce different forces. A trade-off exists with such systems, between the accuracy of tracking and energy dissipation due to switching. A popular way to approach this problem is a Force Shifting Algorithm (FSA). However, in this paper, the trade-off is managed by use of a Model Predictive Control (MPC) algorithm. The tracking accuracy and energy efficiency of the MPC and FSA strategies for DDCs are compared to a PID strategy for standard cylinders. The comparison is obtained by use of a computer simulation of a knuckle boom crane performing a realistic load cycle. The load cycle consists of the crane extending to pick up a load and then retracting to place it at an appropriate location. The main results show that MPC can deliver smoother and more accurate motion than FSA, while using less energy. Compared with standard cylinders and PID control, MPC uses less energy, but due to the switching of chamber pressures, the motion is smoother with the standard strategy. Both FSA and MPC can have degraded performance when a large change in load is introduced.
{"title":"Application of Model Predictive Control in Discrete Displacement Cylinders to Drive a Knuckle Boom Crane","authors":"V. Donkov, T. Andersen, H. Pedersen, M. Ebbesen","doi":"10.1109/GFPS.2018.8472363","DOIUrl":"https://doi.org/10.1109/GFPS.2018.8472363","url":null,"abstract":"In this paper, two Discrete Displacement Cylinders (DDCs) are used to drive the boom of a knuckle boom crane. DDCs operate by connecting one of several available pressure levels to each chamber in order to produce different forces. A trade-off exists with such systems, between the accuracy of tracking and energy dissipation due to switching. A popular way to approach this problem is a Force Shifting Algorithm (FSA). However, in this paper, the trade-off is managed by use of a Model Predictive Control (MPC) algorithm. The tracking accuracy and energy efficiency of the MPC and FSA strategies for DDCs are compared to a PID strategy for standard cylinders. The comparison is obtained by use of a computer simulation of a knuckle boom crane performing a realistic load cycle. The load cycle consists of the crane extending to pick up a load and then retracting to place it at an appropriate location. The main results show that MPC can deliver smoother and more accurate motion than FSA, while using less energy. Compared with standard cylinders and PID control, MPC uses less energy, but due to the switching of chamber pressures, the motion is smoother with the standard strategy. Both FSA and MPC can have degraded performance when a large change in load is introduced.","PeriodicalId":273799,"journal":{"name":"2018 Global Fluid Power Society PhD Symposium (GFPS)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114128932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-07-01DOI: 10.1109/GFPS.2018.8472360
D. Hagen, D. Padovani, M. Ebbesen
Self-contained electro-hydraulic cylinders that can be powered just by an electrical wire will be popular in the coming years. Combining electrical-drives and hydraulic cylin- ders exploits some excellent properties of these two technologies and enables flexible implementation. To fully benefit from such a drive solution, there is the need to develop electro-hydraulic cylinders capable of operating independently as opposed to standard hydraulic systems that are connected to a central power supply. Therefore, this paper presents a numerical investigation of a self-contained electro-hydraulic cylinder with passive load- holding capability. The corresponding dynamic model is proposed and used to predict the system behavior with a view to future implementation. The simulations show the proposed drive guar- antees proper functioning in four-quadrant operations.
{"title":"Study of a Self-Contained Electro-Hydraulic Cylinder Drive","authors":"D. Hagen, D. Padovani, M. Ebbesen","doi":"10.1109/GFPS.2018.8472360","DOIUrl":"https://doi.org/10.1109/GFPS.2018.8472360","url":null,"abstract":"Self-contained electro-hydraulic cylinders that can be powered just by an electrical wire will be popular in the coming years. Combining electrical-drives and hydraulic cylin- ders exploits some excellent properties of these two technologies and enables flexible implementation. To fully benefit from such a drive solution, there is the need to develop electro-hydraulic cylinders capable of operating independently as opposed to standard hydraulic systems that are connected to a central power supply. Therefore, this paper presents a numerical investigation of a self-contained electro-hydraulic cylinder with passive load- holding capability. The corresponding dynamic model is proposed and used to predict the system behavior with a view to future implementation. The simulations show the proposed drive guar- antees proper functioning in four-quadrant operations.","PeriodicalId":273799,"journal":{"name":"2018 Global Fluid Power Society PhD Symposium (GFPS)","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114828928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：