Evaluation of the Performance of a Hydraulic Divider in Synchronizing Actuators under the Influence of Different External Loads

Document Type : Research Paper

Authors

1 Department of Mechanical Engineering, Faculty of Mechanical Engineering, Jundi-Shapur University of Technology,, Dezful, , Iran.

2 Depatment of Mechanical Engineering, Faculty of Mechanical Engineering, , Jundi-Shapur University of Technology,, Dezful,, Iran

Abstract

Hydraulic flow dividers equipped with spool-shaped moving elements play a crucial role in synchronizing hydraulic actuators in power transmission systems, particularly in agricultural machinery. Their performance becomes especially significant when actuators are subjected to unequal external loads, which may lead to flow imbalance. This study investigates the influence of the geometric configuration of the spool element on the flow distribution among hydraulic actuators using both numerical simulations and experimental tests. The results demonstrate that under a load pressure difference of 20 bar, the resultant flow-induced force acting on the spool is reduced by 48.2% and 53.1% for edged and sharp-edged configurations, respectively, compared with the plain spool design. Furthermore, under the same operating conditions, introducing a simple edge on the control surfaces of the divider decreases the flow rate difference between actuators by 43.9%. Substituting the plain spool with a sharp-edged spool leads to a 51.7% reduction in flow imbalance. Overall, the findings highlight that modifications in the spool geometry-particularly the addition of edges on control surfaces-significantly improve the performance of hydraulic flow dividers under differential external loading. This improvement is attributed to the reduction of the effective area exposed to non-uniform oil pressure, thereby enhancing the uniformity of flow distribution among actuators. These results provide valuable insights for the optimized design of hydraulic flow dividers in applications where precise synchronization of actuators is required.

Keywords

Main Subjects

EXTENDED ABSTRACT

 

Introduction

Increasing the accuracy of synchronization of hydraulic actuators under the influence of various external loads is particularly important in the design of hydraulic power transmission systems for both stationary and mobile machines. In recent years, various studies have evaluated the accuracy of hydraulic dividers under the influence of functional quantities of hydraulic power transmission systems, as well as the use of closed-loop control systems, including controllers and intelligent control algorithms, to synchronize linear and rotary actuators. On the other hand, the use of hydraulic dividers, including the spool-shaped moving component, to synchronize the hydraulic actuators, in the structure of many mobile machines, is preferred over other available methods. In past years, no research has been done on improving the accuracy of dividing the oil flow between different hydraulic actuators under the influence of various external loads, through hydraulic dividers, including the moving part of the spool. In this article, due to the importance of the issue, the effect of the geometrical shape of the moving component of the hydraulic divider on the difference in oil flow received by different hydraulic actuators is investigated using numerical and experimental methods.

Method

For the numerical analysis of the oil flow passing through the pilot chambers and orifices resulting from the displacement of three types of moving components of a hydraulic divider, geometric modeling of the divider, definition of the computational domain, its meshing, definition of boundary conditions, and definition of initial conditions are performed, respectively, in Ansys software. For this purpose, a hydraulic divider is used, including a spool-shaped moving component, two inlet ports, and two outlet ports. In the numerical analysis of the flow of oil passing through the orifices resulting from the displacement of the spool-shaped moving component within the internal structure of the hydraulic divider, the Fluent section of the Ansys software utilizes the finite volume method and a pressure-based solver. On the other hand, to compare the results of numerical analysis of parameters related to the oil flow passing through the pilot chambers of a hydraulic divider, consisting of three different moving components, with experimental results, a special hydraulic power transmission system, consisting of two fixed displacement hydraulic motors, is designed and manufactured. In this study, the external load applied to the output shaft of one of the hydraulic motors is assumed to be a constant value. Then, the effect of the external load applied to the output shaft of another hydraulic motor on the force resulting from the flow on the moving component of the hydraulic divider, the oil flow rate sent to the inlet ports of the hydraulic motors, the rotational speed of the output shafts of the motors, and also, the displacement of the moving component of the divider are examined.

Result

The evaluation of the results showed that the average difference of the results obtained from the experimental measurement of the oil flow rate received by the hydraulic motor, under the influence of constant load pressure, through hydraulic dividers, including simple, edged and sharp moving components, with the results obtained from the numerical analysis of the oil flow, is approximately 5.06, 4.66 and 4.36%, respectively. On the other hand, the results obtained from the experimental measurement of oil flow received by the hydraulic motor, under the influence of variable load pressure, by hydraulic dividers, including simple, edged and sharp moving components, differ by 4.85%, 4.4% and 4.13%, respectively, with the results obtained from the numerical analysis of oil flow. Further investigations showed that, under the condition that the load pressure difference of hydraulic motors is equal to 20bar, the use of moving parts with edges and sharp edges, instead of simple moving parts, in the internal structure of the hydraulic divider, reduces the force caused by the flow by 48.2% and 53.1%. Likewise, under similar working conditions, creating a simple edge on the divided pilot surfaces reduces the difference between the received oil flow of hydraulic motors by 43.9%. However, if a sharp-edged moving component is used instead of a simple mobile component in the internal structure of the hydraulic divider, the difference between the oil flow received by the hydraulic motors will be reduced by 51.7%.

Conclusions

In this research, the effect of the geometrical shape of the moving part of the hydraulic divider on the magnitude of the force caused by the oil flow, and as a result, the accuracy of dividing the oil flow between different hydraulic actuators, under the influence of various external loads, was investigated by numerical and experimental methods. The evaluation of the set of results from this research showed that, by reducing the effective area of non-uniform oil pressure in the pilot chambers of the hydraulic divider (creating an edge on the pilot surfaces of the divided movable component), the performance of the hydraulic divider in dividing the oil flow rate between hydraulic actuators, under the influence of different external loads, is significantly improved.

Author Contributions

All authors contributed equally to the conceptualization of the article and writing of the original and subsequent drafts.

Data Availability Statement

Data available on request from the authors.

Ethical considerations

The authors avoided data fabrication, falsification, plagiarism, and misconduct.

Conflict of interest

The authors declare no conflict of interest.

References

Alamgir, A. C., Rodriguez, P. E. (2016). A modular system for energy efficiency study of hydraulic applications. ASEE Annual Conference and Exposition Proceedings. New Orleans, Louisiana, June 26-29. https://doi.org/10.18260/p.26362
Dun, T. A. N., Jianfeng, T., Xuyong, W. (2020). Synchronous control strategy of dual hydraulic motors based on an improved particle swarm optimization algorithm. Journal of Mechanical Engineering, 56(16): 254-261. https://doi.org/10.3901/JME.2020.16.254
Gao, B., Xu, B., Zhang, W.,  Zheng, L. (2024). Characterization of Position Synchronous Control System for Double Hydraulic Cylinder. Recent Advances in Electrical and Electronic Engineering, 17(7), 712–728. https://doi.org/https://doi.org/10.2174/23520965230821102529
Gomez, I., Gonzalez-Mancera, A., Newell, B., Garcia-Bravo, J. (2019). Analysis of the design of a poppet valve by transitory simulation. Energies, 12(5), 889. https://doi.org/10.3390/en12050889
Gu, H., Sun, C., Zhu, W. (2022). Analysis and Improvement of Open Cycle Synchronous Control Hydraulic System for Two Cylinders in a Wind Tunnel. Machine Tool and Hydraulic, 50(5), 124–128.
Havrylenko, O.,  Kulinich, S. (2019). Analyzing an error in the synchronization of hydraulic motor speed under transient operating conditions. Eastern-European Journal of Enterprise Technologies, 4, 30–37. https://doi.org/10.15587/1729-4061.2019.175033
Ledvoň, M., Hružík, L., Bureček, A., Polášek, T., Dýrr, F., Kolář, D. (2023). Experimental and numerical analysis of the flow force acting on the spool of a proportional directional valve. Processes. 11(12), 3415. https://doi.org/10.3390/pr11123415
Li, H., Pang, B. (2019). Research on the synchronization control system of the double hydraulic cylinder four-column Hydraulic Press. Machine Tool and Hydraulics, 47(2), 82-85. https://doi.org/10.3969/j.issn.1001-3881.2019.02.019
Li, J., Wang, Y., Kong, L. (2022). Synchronization characteristics of two vibrators in a novel hydraulic coupling system. Alexandria Engineering Journal, 61(12), 11663-11676.  https://doi.org/10.1016/j.aej.2022.05.040
Li, R., Yuan, W., Ding, X., Xu, J., Sun, Q., Zhang, Y. (2023). Review of research and development of hydraulic synchronous control system. Processes, 11(4), 981. https://doi.org/10.3390/pr11040981
Lu, X., Huang, M. (2018). Modeling, analysis, and control of hydraulic actuator for forging. Eastern European Journal of Enterprise Technologies, 4(7), 30-37. https://doi.org/10.15587/1729-4061.2019.175033
Perepelytsia, V., Kozlov, L., Buriennikov, I., Burennikova, N., Kozlov, S., Rusu, O., Rusu, I. (2023). Optimization of hydraulic drives for synchronizing working movements of the automated brick production installation. International Journal of Modern Manufacturing Technologies, 15(3), 199-207. https://doi.org/ 10.54684/ijmmt.2023.15.3.199
Rafa, A. B., Faraj, Y. A., Saad, A., Hanoon, S. (2014). Theoretical and Experimental Study of Hydraulic Actuators Synchronization by Using Flow Divider Valve. Journal of Engineering and Development, 18(5), 282–293. https://doi.org/10.13140/RG.2.2.11932.95367
Rybak, A., Ivanovskaya, A., Batura, P., Pelipenko, A. (2022). Synchronization in multi-motor hydromechanical systems. Advanced Engineering Research, 21(4), 337–345. https://doi.org/10.23947/2687-1653-2021-21-4-337-345.
Wang, X., Wang, Z., Wang, S., Cai, W., Wu, Q., Ma, W. (2024). Design and Control Performance Optimization of Variable Structure Hydrostatic Drive Systems for Wheel Loaders. Machines, 12(4), 238. https://doi.org/ 10.3390/machines12040238
Wen, Y., Teng, S., Li, Q., Tan, J., Song, Y., Sun, S. (2025). Investigating the Symmetric Control of a Hydraulic System Based on Status Feedback. Symmetry, 17(2), 246.  https://doi.org/10.3390/sym17020246
Wu, L., Wang, L., Zhang, C., Shi, H. (2018). Dynamic characteristics analysis and dual motor synchronous control of hydraulic lifting system for large cranes. The Journal of Engineering, 2019(3), 203-207. https://doi.org/10.1049/joe.2018.9001
Zhu, C., Zhang, H., Wang, W., Li, K., Zhou, Z., He, H. (2022). Compound control on constant synchronous output of double pump-double valve-controlled motor system. Processes, 10(3), 528. https://doi.org/10.3390/pr10030528
 
Iranian Journal of Biosystem Engineering
Volume 56, Issue 3
October 2025
Pages 1-20

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History

  • Receive Date: 19 August 2025
  • Revise Date: 27 September 2025
  • Accept Date: 06 October 2025

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