The authors acknowledge the Beijing Institute of Precision Mechatronics and Controls for supporting this research.

<ol>
	<li>Ketelsen, S., Padovani, D., Andersen, T. O., Ebbesen, M. K., Schmidt, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Classification+and+review+of+pump-controlled+differential+cylinder+drives.">Classification and review of pump-controlled differential cylinder drives.</a> Energies. 12 (7), 1293 (2019).</li><li>Alle, N., Hiremath, S., Makaram, S., Subramaniam, K., Talukdar, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Review+on+electro+hydrostatic+actuator+for+flight+control.">Review on electro hydrostatic actuator for flight control.</a> International Journal of Fluid Power. 17 (2), 125-145 (2016).</li><li>Garrison, M., Steffan, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two-fault+tolerant+electric+actuation+systems+for+space+applications.">Two-fault tolerant electric actuation systems for space applications.</a> 42nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference &amp; Exhibit. , (2006).</li><li>Smith, S., Irving, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electro+hydrostatic+actuators+for+control+of+undersea+vehicles.">Electro hydrostatic actuators for control of undersea vehicles.</a> Joint Undersea Warfare Technology Fall Conference. , (2006).</li><li>Gao, B., Fu, Y., Pei, Z., Ma, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Research+on+dual-variable+integrated+electro-hydrostatic+actuator.">Research on dual-variable integrated electro-hydrostatic actuator.</a> Chinese Journal of Aeronautics. 19 (1), 77-82 (2006).</li><li>Yan, X., Yu, L., Pan, J., Fu, J., Fu, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Control+dynamic+performance+analysis+of+a+novel+integrated+electro+mechanical+hydrostatic+actuator.">Control dynamic performance analysis of a novel integrated electro mechanical hydrostatic actuator.</a> The Proceedings of the 2018 Asia-Pacific International Symposium on Aerospace Technology (APISAT 2018). APISAT 2018. Lecture Notes in Electrical Engineering. 459, 2563-2573 (2018).</li><li>Liu, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The researches of state space modeling method and dynamic properties for double variable electro-hydraulic servo control system. , (2015).</li><li>Jean-Charles, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Best+practices+for+model-based+and+simulation-aided+engineering+of+power+transmission+and+motion+control+systems.">Best practices for model-based and simulation-aided engineering of power transmission and motion control systems.</a> Chinese Journal of Aeronautics. 32 (1), 186-199 (2019).</li><li>Xue, L., Wu, S., Xu, Y., Ma, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simulation-based+multiobjective+optimization+design+method+for+pump-driven+electro-hydrostatic+actuators.">A simulation-based multiobjective optimization design method for pump-driven electro-hydrostatic actuators.</a> Processes. 7, 274 (2019).</li><li>Andersson, J., Krus, P., Nilsson, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimization+as+a+support+for+selection+and+design+of+aircraft+actuation+systems.">Optimization as a support for selection and design of aircraft actuation systems.</a> 7th AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization. , 4887 (1998).</li><li>Andersson, J., Krus, P., Nilsson, K., Storck, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modelling+and+simulation+of+heat+generation+in+electro-hydrostatic+actuation+systems.">Modelling and simulation of heat generation in electro-hydrostatic actuation systems.</a> Proceedings of the JFPS international symposium on fluid power. The Japan Fluid Power System Society. 314, 537-542 (1999).</li><li>Budinger, M., Reysset, A., Halabi, T. E., Vasiliu, C., Mare, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimal+preliminary+design+of+electromechanical+actuators.">Optimal preliminary design of electromechanical actuators.</a> Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering. 228 (9), 1598-1616 (2014).</li><li>Liscou&#235;t, J., Budinger, M., Mare, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+for+reliability+of+electromechanical+actuators.">Design for reliability of electromechanical actuators.</a> 5th International Conference on Recent Advances in Aerospace Actuation Systems and Components. , 174-182 (2010).</li><li>Arriola, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+model-based+method+to+assist+the+architecture+selection+and+preliminary+design+of+flight+control+electro-mechanical+actuators.">A model-based method to assist the architecture selection and preliminary design of flight control electro-mechanical actuators.</a> 7th International Conference on Recent Advances in Aerospace Actuation Systems and Components. , 166-174 (2016).</li><li>Baer, K., Ericson, L., Krus, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Framework+for+simulation-based+simultaneous+system+optimization+for+a+series+hydraulic+hybrid+vehicle.">Framework for simulation-based simultaneous system optimization for a series hydraulic hybrid vehicle.</a> International Journal of Fluid Power. , (2018).</li><li>Hong, G., Wei, T., Ding, X., Duan, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multi-objective+optimal+design+of+electro-hydrostatic+actuator+driving+motors+for+low+temperature+rise+and+high+power+weight+ratio.">Multi-objective optimal design of electro-hydrostatic actuator driving motors for low temperature rise and high power weight ratio.</a> Energies. 11 (5), 1173 (2018).</li><li>Sun, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiobjective+and+multiphysics+design+optimization+of+a+switched+reluctance+motor+for+electric+vehicle+applications.">Multiobjective and multiphysics design optimization of a switched reluctance motor for electric vehicle applications.</a> IEEE Transactions on Energy Conversion. 36 (4), 3294-3304 (2021).</li><li>Gerada, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Holistic+electrical+machine+optimization+for+system+integration.">Holistic electrical machine optimization for system integration.</a> IEEE 3rd International Future Energy Electronics Conference and ECCE Asia (IFEEC 2017-ECCE Asia). IEEE. , 980-985 (2017).</li><li>Golovanov, D., Papini, L., Gerada, D., Xu, Z., Gerada, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multidomain+optimization+of+high-power-density+PM+electrical+machines+for+system+architecture+selection.">Multidomain optimization of high-power-density PM electrical machines for system architecture selection.</a> IEEE Transactions on Industrial Electronics. 65 (7), 5302-5312 (2017).</li><li>Han, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multidisciplinary+model+for+preliminary+design+of+electro-mechanical+servo+pump.">Multidisciplinary model for preliminary design of electro-mechanical servo pump.</a> Scandinavian International Conference on Fluid Power. , 362-374 (2019).</li><li>Liscou&#235;t, J., Budinger, M., Mar&#233;, J. C., Orieux, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modelling+approach+for+the+simulation-based+preliminary+design+of+power+transmissions.">Modelling approach for the simulation-based preliminary design of power transmissions.</a> Mechanism and Machine Theory. 46 (3), 276-289 (2011).</li><li>Negoita, G. C., Mare, J. C., Budinger, M., Vasiliu, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Scaling-laws+based+hydraulic+pumps+parameter+estimation.">Scaling-laws based hydraulic pumps parameter estimation.</a> UPB Scientific Bulletin, Series D: Mechanical Engineering. 74 (2), 199-208 (2012).</li><li>Marc, B., Jonathan, L., Fabien, H., Mar&#233;, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimation+models+for+the+preliminary+design+of+electromechanical+actuators.">Estimation models for the preliminary design of electromechanical actuators.</a> Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering. 226 (3), 243-259 (2012).</li><li>Kauranne, H. O. J., Kajaste, J. T., Ellman, A. U., Pietola, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Applicability+of+pump+models+for+varying+operational+conditions.">Applicability of pump models for varying operational conditions.</a> ASME International Mechanical Engineering Congress. , 45-54 (2008).</li><li>Bergman, T. L., Incropera, F. P., DeWitt, D. P., Lavine, A. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Fundamentals of Heat and Mass Transfer. , (2011).</li><li>Whitaker, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Forced+convection+heat+transfer+correlations+for+flow+in+pipes,+past+flat+plates,+single+cylinders,+single+spheres,+and+for+flow+in+packed+beds+and+tube+bundles.">Forced convection heat transfer correlations for flow in pipes, past flat plates, single cylinders, single spheres, and for flow in packed beds and tube bundles.</a> AIChE Journal. 18 (2), 361-371 (1972).</li><li>Li, C., Jiao, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calculation+method+for+thermal-hydraulic+system+simulation.">Calculation method for thermal-hydraulic system simulation.</a> Journal of Heat Transfer. 130 (8), 1-5 (2008).</li><li>Li, C., Jiao, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermal-hydraulic+modeling+and+simulation+of+piston+pump.">Thermal-hydraulic modeling and simulation of piston pump.</a> Chinese Journal of Aeronautics. 19 (4), 354-358 (2006).</li><li>Andersson, J., Krus, P., Nilsson, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modelling+and+simulation+of+heat+generation+in+electro-hydrostatic+actuation+systems.">Modelling and simulation of heat generation in electro-hydrostatic actuation systems.</a> Proceedings of the JFPS International Symposium on Fluid Power. 1999 (4), 537-542 (1999).</li><li>Pawlus, W., Hansen, M. R., Choux, M., Hovland, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitigation+of+fatigue+damage+and+vibration+severity+of+electric+drivetrains+by+systematic+selection+of+motion+profiles.">Mitigation of fatigue damage and vibration severity of electric drivetrains by systematic selection of motion profiles.</a> IEEE/ASME Transactions on Mechatronics. 21 (6), 2870-2880 (2016).</li><li>Hu, B., Fu, J., Fu, Y., Zhang, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+system+design+for+a+novel+aerospace+electrically+actuator.">Measurement system design for a novel aerospace electrically actuator.</a> Proceedings of 2021 Chinese Intelligent Systems Conference. , 612-620 (2022).</li><li>De Giorgi, F., Budinger, M., Hazyuk, I., Reysset, A., Sanchez, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reusable+surrogate+models+for+the+preliminary+design+of+aircraft+application+systems.">Reusable surrogate models for the preliminary design of aircraft application systems.</a> AIAA Journal. 59 (7), 1-13 (2021).</li><li>Kreitz, T., Arriola, D., Thielecke, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Virtual+performance+evaluation+for+electro-mechanical+actuators+considering+parameter+uncertainties.">Virtual performance evaluation for electro-mechanical actuators considering parameter uncertainties.</a> 6th International Conference on Recent Advances in Aerospace Actuation Systems and Components. 2014, 136-142 (2014).</li><li>Sanchez, F., Budinger, M., Hazyuk, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dimensional+analysis+and+surrogate+models+for+the+thermal+modeling+of+multiphysics+systems.">Dimensional analysis and surrogate models for the thermal modeling of multiphysics systems.</a> Applied Thermal Engineering. 110, 758-771 (2017).</li></ol>

The authors have nothing to disclose.

The concept and other technical components of the EVDP have been presented in previous publications6,31, demonstrating the applicability and advantages of the EVDP. Instead of studying the EVDP itself, this paper continued to study the design method in relation to future real application needs. A specific design method is necessary for this type of highly integrated and multidisciplinary coupling product, which calls for delicate performance trade-offs and optimi...

Electro-hydrostatic actuators (EHAs) are receiving increasing interest for applications such as industrial presses, large mobile machinery, crane manipulators, and primary aircraft control due to their combination of the advantages of both electric actuators and hydraulic actuators1. Two basic types of EHAs can be identified: variable-speed EHAs and variable-displacement EHAs2. Currently, the variable-speed EHA is more popular than the variable-displacement EHA due to its higher efficiency and simplicity. However, along with the higher power level of the EHA, which is needed in heavy vehicles, such as heavy launch vehicles3 and submarines4, the driving motor and associated electronics of the variable-speed EHA have issues related to low dynamics, high thermal dissipation, high price, etc. Therefore, the variable-displacement EHA is being reconsidered for these high-power applications (&#62;30 kW), as its control is realized via a low-power device that regulates the pump displacement.
One major concern that prevents variable-displacement EHA being taken as a priority is its cumbersome pump displacement control unit, which itself is a complete valve-controlled hydraulic system. The electro-variable displacement pump (EVDP) has been proposed to address this issue by using a compact electric displacement control unit. This design improves the compactness, efficiency, etc., of the variable-displacement EHA, which resolves the previous weakness to a certain degree. Therefore, the use of variable-displacement EHAs for high-power applications may be facilitated by using the newly proposed EVDP. However, the complexity of the EVDP is significantly greater compared to the conventional hydraulically controlled variable-displacement pump as it integrates components from several new disciplines. Consequently, specific EVDP-based research activities have emerged. Our research group started the EVDP research5 and has continued to develop it6. Liu developed the EVDP for EHA applications and performed experimental tests7. Some hydraulic companies also provide EVDP products. In addition to the research regarding the technical components of the EVDP, the design method for responding to real application requirements is also significant for enhancing the EVDP&#39;s competence by further reducing the cost of using EVDPs and exploring their performance potential. Hence, a specific EVDP preliminary design method is necessary for optimizing trade-offs in its system-level performance by analyzing its coupled disciplines. The simulation-based preliminary design is of interest for this type of multidisciplinary coupling of mechatronic products8.
Although no specific simulation models for EVDP preliminary design have been proposed due to it being a newly proposed concept, much research has been invested in related mechatronic products. A dynamic EHA model has been built to optimize the weight, efficiency, and control performance in preliminary design9, but the lifetime, reliability, thermal characteristics, etc., were not involved, which are essential performance indexes that should be considered in preliminary design. Another dynamic EHA model has also been used to optimize cost, efficiency, and control performance10, and a thermal model was subsequently developed to evaluate the thermal characteristics of the optimized EHA11, but the reliability and lifetime were not considered. A comprehensive electro-mechanical actuator (EMA) preliminary design method has been presented12. Specific models with different functions capable of analyzing different characteristics have been proposed for this method, and reliability and lifetime models have also been developed13. The mechanical strength, power capability, thermal performance, etc., could hereby be evaluated, but the control performance was not involved. Another EMA preliminary design method utilized a dynamic EMA model and associated component sizing models14. The cost, weight, fatigue life, power capacity, physical constraints, etc., were involved in the simulation analysis, but reliability and control performance were not included. A dynamic model was proposed for the optimization design of a hydraulic hybrid drive train15. The power capacity, efficiency, control, etc., could be simulated, but the reliability and life were not considered. Models for analyzing an EHA-based flight control actuation system have been proposed, within which simple power transmission equations and weight functions were used16. Considering that the models were used for vehicle-level and mission-level analyses, the limited attribute coverage of the models was appropriate. As a major component of the EHA, servo motors have attracted separate attention regarding modeling and design, and the results are also instructive for EHA model development. Thermal networks, weight models, etc., can also be considered for EHA modeling17,18,19. The reviewed literature indicates that, even considering the results from products related to the EVDP, the developed models do not analyze all the influential performance attributes of the products for the preliminary design. The control performance, thermal performance, reliability, and lifetime are the attributes that have been most neglected in construction of the models. Therefore, this paper proposes a model package capable of analyzing all the most influential performance attributes for the EVDP preliminary design. The simulation analysis is also presented to better illustrate the model functions. This paper is an extension of a previous publication20, as it improves the parameter generation, involves the lifetime model, reliability model, and control model, optimizes the calculation cost, validates the model, and conducts in-depth simulation analysis, etc.
The conventional hydraulic control unit of a variable-displacement piston pump is replaced with an electric actuator to improve the compactness and reduce heat dissipation, as shown in Figure 1. The electric actuator consists of a ball screw, a gearbox, and a permanent magnet synchronous motor (PMSM). The electric actuator connects the swashplate via a bar to regulate the pump displacement. When applied in EHAs, the EVDP swashplate rotational position is closed-loop controlled by modulating the PMSM. The electric actuator is integrated with the piston pump in a mutual case to form an integral component. This design submerges the electric actuator in the working fluid and hereby strengthens the multi-domain coupling effects.
As the EVDP is a typical multi-domain mechatronic product, its preliminary design plays an essential role in optimizing trade-offs in its system-level performance and outlining the component design requirements. The process is illustrated in Figure 2 based on the simulation-based design scheme10,12. Step 1 firstly analyzes the selected EVDP architecture, as in Figure 1, and concludes the design parameters based on the specified performance requirements. Then, the design task is usually transformed into an optimization problem to explore the performance optimization of the EVDP. This is carried out by converting the design parameters into optimization variables and converting the performance requirements into objectives and constraints. It is worth noting that the design parameters need to be classified into active, driven, and empirical categories. Only the active parameters are used as optimization variables due to their independence features. The other two categories are automatically generated by estimation from the active parameters. Therefore, Step 2 develops the estimation models of the driven and empirical parameters. These estimation tools are used in each iteration of the optimization, as well as in Step 5 for formulating all the required simulation parameters. Step 3 builds the calculation models for each optimization objective or constraint, which reflects the required performance. These models should be computationally efficient; otherwise, the optimization calculation cost would be unacceptable. Step 4 performs the optimization calculation, which is usually multi-objective and multidisciplinary. It also deals with the parameter uncertainties in the preliminary design phase. Step 5 constructs an overall model of the designed EVDP and uses it for validating the optimization results by simulating the EVDP under typical duty cycles. This model is the ultimate tool for evaluating the preliminary design results. Therefore, this model should have the highest fidelity and involve all the influential characteristics in a tight coupling style. Finally, the preliminary design performance results and the system-level dimensioning results are obtained.
This paper focuses on the system modeling and simulation method of the EVDP, which involves conducting the parameter analysis in Step 1 and completing Steps 2 and 5. Firstly, the design parameters are derived based on the EVDP architecture and the design requirements, and they are classified into three sub-categories. Secondly, the estimation models for the non-active parameters are developed based on scaling laws, component catalogs, empirical functions, etc. Thirdly, the overall model of the EVDP is constructed using multidisciplinary coupling equations and additional lifetime and reliability sub-models, and the model is partially verified by experiments. Lastly, the previous sizing results are imported into the constructed model to perform simulation analysis under typical duty cycles. The system-level performance is deduced based on the simulation results. The parameter sensitivity and the robustness of the design are also evaluated. As a result, this paper develops a specific modeling and simulation method for EVDP preliminary design. The EVDP&#39;s performance for application in the EHA is comprehensively predicted. The proposed method stands as a practical tool for developing EVDPs and variable-displacement EHAs for high-power applications. The method can also be referred to for developing simulation tools for other types of mechatronic products. The EVDP in this paper refers to the electro-mechanically controlled variable-displacement pump, but the electro-hydraulically controlled variable-displacement pump is out of the scope of this paper.

<table><tbody><tr><td>Ball screw</td><td>NSK</td><td>PSS</td><td></td></tr><tr><td>EVDP prototype</td><td>Beijing Institute of Precision Mechatronics and Controls</td><td>customized</td><td>7.4 mL/rev, 7000 rpm, 21 Mpa</td></tr><tr><td>EVDP testrig</td><td>Beijing Institute of Precision Mechatronics and Controls</td><td>customized</td><td>Refer to Figure 7, can be adapted upon individual needs. Including Power PMAC controller, ELMO Whistle Driver, etc.</td></tr><tr><td>Gearhead</td><td>Maxon</td><td>GP</td><td></td></tr><tr><td>Matlab</td><td>Mathworks</td><td>R2020a</td><td></td></tr><tr><td>Permannet magnet synchronous motor</td><td>Maxon</td><td>393023</td><td></td></tr><tr><td>Piston pump</td><td>Bosch Rexroth</td><td>A10VZO</td><td></td></tr><tr><td>Simcenter Amesim</td><td>Siemens</td><td>2021.1</td><td>system simulation platform</td></tr></tbody></table>

a modeling and simulation method for preliminary design of an electro-variable displacement pump

Electro-hydrostatic actuators (EHAs) have been considerably researched in academia, and their applications in various industrial fields are expanding. The variable-speed EHA has now taken priority over the variable-displacement EHA, but its driving motor and associated electronics encounter issues when applied in high-power applications: low-dynamics, high thermal dissipation, high price, etc. Therefore, a variable-displacement EHA equipped with an electro-variable displacement pump (EVDP) has been considered. The EVDP itself is a mechatronic system that integrates a piston pump, a ball screw, a gearbox, and a permanent magnet synchronous motor (PMSM). Consequently, the EVDP needs to be investigated to ensure its system-level performance when applied in an EHA. In addition to the previous research on the technical parameters of the EVDP, a dedicated design method is necessary for further reducing the cost of using the EVDP and exploring its performance potential. Here, a simulation based EVDP preliminary design method is selected for designing a 37 kW EVDP. Firstly, a previously proposed multidisciplinary model of the EVDP is extended by improving the parameter generation, including the EVDP life, reliability, control models, etc. Secondly, the proposed model is partially verified using a downsized prototype. Thirdly, the EVDP is simulated at a system level, supported by the proposed model. The EVDP performance is evaluated according to the specified design requirements. The temperature, bandwidth and accuracy, reliability and lifetime, etc., are all predicted for the EVDP. The simulation results demonstrate the EVDP's applicability in variable-displacement EHA. The proposed modeling and simulation method can be used to evaluate diverse EVDP performance and respond to general design requirements. The method can also support the resolution of the preliminary design challenges in terms of limited information and robustness. Therefore, the proposed method is appropriate for the realization of the simulation-based EVDP preliminary design method.

This section presents the results obtained from performing all the protocol steps, which constitute part of Step 1, all of Step 2, and all of Step 5 of the EVDP preliminary design method in Figure 2. The input information in the protocol includes the EVDP schematics in Figure 1, the optimized active parameters (clarified in Step 5.1.1.) of the EVDP from Step 4 of Figure 2, and the EVDP performance simulation tasks, which relate to t...

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A Modeling and Simulation Method for Preliminary Design of an Electro-Variable Displacement Pump

A simulation model specifically supporting the preliminary design of an electro-variable displacement pump (EVDP) is developed and partially verified by experiments. The control performance, life, reliability, etc., can all be evaluated using the proposed model, which covers the main performance requirements under the EVDP preliminary design task.

Electro-hydrostatic actuators (EHAs) have been considerably researched in academia, and their applications in various industrial fields are expanding. The ...

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3.0K Views.  Beihang University. Elektrohydrostatische activatoren ondersteunen de elektrificatie van zware systemen. Om minder energieverbruik te bereiken, concentreert onze methode zich op optimalisatie, elektrovariabele verplaatsingspompgebruik van de systemen. Onze modellering en de simulatiemethode ondersteunen het voorontwerp.Onze elektrovariabele verdringingspomp, die moet kiezen voor volledige prestatievoorspelling, automatische parametergeneratie en ontwerprobuustheid. Begin met het classificeren van de param...

Video: A Modeling and Simulation Method for Preliminary Design of an Electro-Variable Displacement Pump

Simulation, Fabrication and Characterization of THz Metamaterial Absorbers

Metamaterials (MM), artificial materials engineered to have properties that may not be found in nature, have been widely explored since the first theoretical1 and experimental demonstration2 of their unique properties. MMs can provide a highly controllable electromagnetic response, and to date have been demonstrated in every technologically relevant spectral range including the optical3, near IR4, mid IR5 , THz6 , mm-wave7 , microwave8 and radio9 bands. Applications include perfect lenses10, sensors11, telecommunications12, invisibility cloaks13 and filters14,15. We have recently developed single band16, dual band17 and broadband18 THz metamaterial absorber devices capable of greater than 80% absorption at the resonance peak. The concept of a MM absorber is especially important at THz frequencies where it is difficult to find strong frequency selective THz absorbers19. In our MM absorber the THz radiation is absorbed in a thickness of ~ &lambda;/20, overcoming the thickness limitation of traditional quarter wavelength absorbers. MM absorbers naturally lend themselves to THz detection applications, such as thermal sensors, and if integrated with suitable THz sources (e.g. QCLs), could lead to compact, highly sensitive, low cost, real time THz imaging systems.

This protocol outlines the simulation, fabrication and characterization of THz metamaterial absorbers. Such absorbers, when coupled with an appropriate sensor, have applications in THz imaging and spectroscopy.

Metamaterials (MM),  artificial materials engineered to have properties that may not be found in  nature, have been widely explored since the first ...

A Cost-effective and Reliable Method to Predict Mechanical Stress in Single-use and Standard Pumps

Pumps are mainly used when transferring sterile culture broths in biopharmaceutical and biotechnological production processes. However, during the pumping process shear forces occur which can lead to qualitative and/or quantitative product loss. To calculate the mechanical stress with limited experimental expense, an oil-water emulsion system was used, whose suitability was demonstrated for drop size detections in bioreactors1. As drop breakup of the oil-water emulsion system is a function of mechanical stress, drop sizes need to be counted over the experimental time of shear stress investigations. In previous studies, the inline endoscopy has been shown to be an accurate and reliable measurement technique for drop size detections in liquid/liquid dispersions. The aim of this protocol is to show the suitability of the inline endoscopy technique for drop size measurements in pumping processes. In order to express the drop size, the Sauter mean diameter d32 was used as the representative diameter of drops in the oil-water emulsion. The results showed low variation in the Sauter mean diameters, which were quantified by standard deviations of below 15%, indicating the reliability of the measurement technique.

Shear stress investigations on an oil-water emulsion system result in drop breakup over the experimental time. To count drop sizes in pumping processes, the suitability of inline endoscopy was successfully demonstrated in this protocol.

Pumps are mainly used when transferring sterile culture broths in biopharmaceutical and biotechnological production processes. However, during the pumping ...

Design and Use of a Full Flow Sampling System (FFS) for the Quantification of Methane Emissions

The use of natural gas continues to grow with increased discovery and production of unconventional shale resources. At the same time, the natural gas industry faces continued scrutiny for methane emissions from across the supply chain, due to methane&#39;s relatively high global warming potential (25-84x that of carbon dioxide, according to the Energy Information Administration). Currently, a variety of techniques of varied uncertainties exists to measure or estimate methane emissions from components or facilities. Currently, only one commercial system is available for quantification of component level emissions and recent reports have highlighted its weaknesses.
In order to improve accuracy and increase measurement flexibility, we have designed, developed, and implemented a novel full flow sampling system (FFS) for quantification of methane emissions and greenhouse gases based on transportation emissions measurement principles. The FFS is a modular system that consists of an explosive-proof blower(s), mass airflow sensor(s) (MAF), thermocouple, sample probe, constant volume sampling pump, laser based greenhouse gas sensor, data acquisition device, and analysis software. Dependent upon the blower and hose configuration employed, the current FFS is able to achieve a flow rate ranging from 40 to 1,500 standard cubic feet per minute (SCFM). Utilization of laser-based sensors mitigates interference from higher hydrocarbons (C2+). Co-measurement of water vapor allows for humidity correction. The system is portable, with multiple configurations for a variety of applications ranging from being carried by a person to being mounted in a hand drawn cart, on-road vehicle bed, or from the bed of utility terrain vehicles (UTVs). The FFS is able to quantify methane emission rates with a relative uncertainty of &#177; 4.4%. The FFS has proven, real world operation for the quantification of methane emissions occurring in conventional and remote facilities.

Design and Use of a Full Flow Sampling System FFS for the Quantification of Methane Emissions

We have designed, developed, and implemented a novel full flow sampling system (FFS) for quantification of methane emissions and greenhouse gases from across the natural gas supply chain.

The use of natural gas continues to grow with increased discovery and production of unconventional shale resources. At the same time, the natural gas ...

High Speed Droplet-based Delivery System for Passive Pumping in Microfluidic Devices

A novel microfluidic system has been developed that uses the phenomenon of passive pumping along with a user controlled droplet based fluid delivery system. Passive pumping is the phenomenon by which surface tension induced pressure differences drive fluid movement in closed channels. The automated fluid delivery system consists of a set of voltage controlled valves with micro-nozzles connected to a fluid reservoir and a control system. These voltage controlled valves offer a volumetrically precise way to deliver fluid droplets to the inlet of a microfluidic device in a high frequency manner. Based on the  dimensions demonstrated in the current study example, the system is capable of flowing 4 milliliters per minute (through a 2.2mm by 260um cross-sectional channel). Based on these same channel dimensions, fluid exchange of a point inside the channel can be achieved in as little as eight milliseconds. It is observed that there is interplay between momentum of the system (imparted by a combination of the droplets created by the valves and the fluid velocity in the channel), and the surface tension of the liquid. Where momentum provides velocity to the fluid flow (or vice-versa), equilibration of surface tension at the inlet provides a sudden stop to any flow. This sudden stop allows the user to control the flow characteristics of the channel and opens the door for a variety of biological applications, ranging anywhere from reagent delivery to drug-cell studies. It is also observed that when nozzles are aimed at the inlet at shallow angles, the droplet momentum can cause additional interesting fluid phenomena, such as mixing of multiple droplets in the inlet.

A novel microfluidic system has been developed using the phenomenon of passive pumping and a user controlled fluid delivery system. This microfluidic system has the potential to be used in a wide variety of biological applications given its low cost, ease of use, volumetric precision, high speed, repeatability and automation.

A novel microfluidic system has been developed that uses the phenomenon of passive pumping along with a user controlled droplet based fluid delivery ...

Biology

A Rapid Method for Modeling a Variable Cycle Engine

The variable cycle engines (VCE) that combine the advantages of turbofan and turbojet engines, are widely considered to be the next generation aircraft engines. However, developing VCE requires high costs. Thus, it is essential to build a mathematical model when developing an aircraft engine, which may avoid a large number of real tests and reduce the cost dramatically. Modeling is also crucial in control law development. In this article, based on a graphical simulation environment, a rapid method for modeling a double bypass variable cycle engine using object-oriented modeling technology and modular hierarchical architecture is described. Firstly, the mathematical model of each component is built based on the thermodynamic calculation. Then, a hierarchical engine model is built via the combination of each component mathematical model and the N-R solver module. Finally, the static and dynamic simulations are carried out in the model and the simulation results prove the effectiveness of the modeling method. The VCE model built through this method has the advantages of clear structure and real-time observation.

Here, we present a protocol to build a component-level mathematical model for a variable cycle engine.

The variable cycle engines (VCE) that combine the advantages of turbofan and turbojet engines, are widely considered to be the next generation aircraft ...

Interactive and Visualized Online Experimentation System for Engineering Education and Research

Experimentation is crucial in engineering education. This work explores visualized experiments in online laboratories for teaching and learning and also research. Interactive and visualizing features, including theory-guided algorithm implementation, web-based algorithm design, customizable monitoring interface, and three-dimensional (3-D) virtual test rigs are discussed. To illustrate the features and functionalities of the proposed laboratories, three examples, including the first-order system exploration using a circuit-based system with electrical elements, web-based control algorithm design for virtual and remote experimentation, are provided. Using user-designed control algorithms, not only can simulations be conducted, but real-time experiments can also be conducted once the designed control algorithms have been compiled into executable control algorithms. The proposed online laboratory also provides a customizable monitoring interface, with which users can customize their user interface using provided widgets such as the textbox, chart, 3-D, and camera widget. Teachers can use the system for online demonstration in the classroom, students for after-class experimentation, and researchers to verify control strategies.

This work describes an online experimentation system that provides visualized experiments, including the visualization of theories, concepts, and formulas, visualizing the experimental process with three-dimensional (3-D) virtual test rigs, and visualizing the control and monitoring system using widgets such as charts and cameras.

Experimentation is crucial in engineering education. This work explores visualized experiments in online laboratories for teaching and learning and also ...

Modeling and Experimental Analysis of the Single-Shaft Coaxial Motor-Pump Assembly in Electrohydrostatic Actuators

An electrohydrostatic actuator (EHA) can be the most promising alternative compared with the traditional hydraulic servo actuators for its high power density, ease of maintenance, and reliability. As the core power unit that determines the performance and service life of the EHA, the motor-pump assembly should simultaneously possess a wide speed/pressure range and a high dynamic response.
This paper presents a method to test the performance of the motor-pump assembly through simulation and experimentation. The flow output characteristics were defined through simulation and analysis of the assembly at the beginning of the experiment, leading to the conclusion of whether the pump could meet the requirements of the EHA. A series of performance tests were conducted on the motor-pump assembly via a pump test bench in the speed range of 1,450-9,000 rpm and the pressure range of 1-30 MPa.
We tested the overall efficiency of the motor-pump assembly under various working conditions after confirming the consistency between the test results of the flow output characteristics with the simulation results. The results showed that the assembly has higher overall efficiency when working at 4,500-7,000 rpm under the pressure of 10-25 MPa and at 2,000-2,500 rpm under 5-15 MPa. Overall, this method can be utilized for determining in advance whether the motor-pump assembly meets the requirements of EHA. Moreover, this paper proposes a rapid test method of the motor-pump assembly in various working conditions, which could assist in predicting EHA performance.

We built a simulation model to evaluate pump flow characteristics and performance of the single-shaft coaxial motor-pump assembly in electrohydrostatic actuators and investigate the overall efficiency in a wide set of working conditions of the motor-pump assembly experimentally.

An electrohydrostatic actuator (EHA) can be the most promising alternative compared with the traditional hydraulic servo actuators for its high power ...

Design and Application of a Fault Detection Method Based on Adaptive Filters and Rotational Speed Estimation for an Electro-Hydrostatic Actuator

The electro-hydrostatic actuator (EHA) is a promising actuating apparatus used in flight control systems for more electric aircraft (MEA) due to its high power density and low maintenance. Since the reliability of the system decreases with increasing complexity, fault detection is becoming increasingly important. In this paper, an adaptive filter was designed based on a normalized least mean square (NLMS) algorithm, which could identify the resistance of the motor windings online to detect electrical faults in the EHA. Additionally, based on the analytical relationship between rotational speed and displacement, a rotational speed estimation method was designed. By comparing the actual rotational speed with the estimated one, hydraulic faults could be detected. To verify the efficacy of the aforementioned method, software was applied for the modeling and simulations, which included fault injection and detection. On this basis, an experimental platform was built and then subjected to a series of validation experiments. The results indicate that the fault detection method has the potential to detect electrical and hydraulic faults in an EHA.

In this paper, an adaptive filter based on a normalized least mean square (NLMS) algorithm and a rotational speed estimation method are introduced to detect the electrical and hydraulic faults of the electro-hydrostatic actuator (EHA). The efficacy and feasibility of the aforementioned methods are verified through simulations and experiments.

The electro-hydrostatic actuator (EHA) is a promising actuating apparatus used in flight control systems for more electric aircraft (MEA) due to its high ...

A Performance-testing Platform for a Conduction Micropump with an FR-4 Copper-clad Electrode Plate

Here, a conduction micropump with symmetric planar electrode pairs prepared on flame-retardant glass-reinforced epoxy (FR-4) copper-clad laminate (CCL) is fabricated. It is used to investigate the influence of chamber dimensions on the performance of a conduction micropump and to determine the reliability of the conduction pump when acetone is used as the working fluid. A testing platform is set up to evaluate conduction micropump performance under different conditions. When the chamber height is 0.2 mm, the pump pressure reaches its peak value.

This paper presents a protocol for the fabrication of a conduction micropump using symmetric planar electrodes on flame-retardant glass-reinforced epoxy (FR-4) copper-clad laminate (CCL) to test the influence of chamber dimensions on the performance of a conduction micropump.

Here, a conduction micropump with symmetric planar electrode pairs prepared on flame-retardant glass-reinforced epoxy (FR-4) copper-clad laminate (CCL) is ...

Bioengineering

Three-dimensional Printing of Thermoplastic Materials to Create Automated Syringe Pumps with Feedback Control for Microfluidic Applications

Microfluidics has become a critical tool in research across the biological, chemical, and physical sciences. One important component of microfluidic experimentation is a stable fluid handling system capable of accurately providing an inlet flow rate or inlet pressure. Here, we have developed a syringe pump system capable of controlling and regulating the inlet fluid pressure delivered to a microfluidic device. This system was designed using low-cost materials and additive manufacturing principles, leveraging three-dimensional (3D) printing of thermoplastic materials and off-the-shelf components whenever possible. This system is composed of three main components: a syringe pump, a pressure transducer, and a programmable microcontroller. Within this paper, we detail a set of protocols for fabricating, assembling, and programming this syringe pump system. Furthermore, we have included representative results that demonstrate high-fidelity, feedback control of inlet pressure using this system. We expect this protocol will allow researchers to fabricate low-cost syringe pump systems, lowering the entry barrier for the use of microfluidics in biomedical, chemical, and materials research.

Here we present a protocol to construct a pressure-controlled syringe pump to be used in microfluidic applications. This syringe pump is made from an&#160;additively manufactured body, off-the-shelf hardware, and open-source electronics. The resulting system is low-cost, straightforward to build, and delivers well-regulated fluid flow to enable rapid microfluidic research.

Microfluidics has become a critical tool in research across the biological, chemical, and physical sciences. One important component of microfluidic ...

A Modeling and Simulation Method for Preliminary Design of an Electro-Variable Displacement Pump

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