Method for combining valves with symmetric and asymmetric cylinders for hydraulic systems
Keywords:Electro-hydraulic system, hydraulic circuit design, component sizing, asymmetric and symmetric cylinder, proportional valve
Electro-hydraulic position control systems are widely applied in several fields. The valve and cylinder configuration and the dimensioning of these systems is dependent on the requested transient response and the load profile. One of the primary factors in this regards is the selection of an asymmetric or symmetric cylinder, considering issues such as the area available for installation and the asymmetry of the external loading. According to the classical literature, the valve control orifice areas must be matched with the cylinder areas to ensure balanced pressure variation in the cylinder chambers. Moreover, considering that several real applications use non-matched components, it is evident that, depending on the system parameters and load characteristics, good performance can be obtained with this system configuration. Based on non-linear dynamic modelling and experimental results, the transient instants when cavitation or high pressure peaks can occur are determined. Subsequently, a set of equations establishing the relationship between the valve control orifice ratio and cylinder area ratio are derived. A method for determining the valve characteristics, based on parameters such as moved mass, external load force and cylinder asymmetry, is presented. The results obtained are also valid for speed control in open or closed loop system.
Asaff, Y., De Negri, V.J., and Soares, J.M.C., 2015. Pneutronic
speed governor for small hydropower plants: a new application
for pneumatics. Journal of the Brazilian Society of
Mechanical Sciences and Engineering, 38, 2621–2633.
De Negri, V.J., Ramos Filho, J.R.B., and Souza, A.D.C.,
A design method for hydraulic positioning systems.
In: 51th National Conference on Fluid Power
(NCFP), Las Vegas, USA: NFPA, 669–679.
Destro, M.C., 2014. Análise de condições operacionais
críticas em posicionadores eletro-hidráulicos (in
Portuguese). Thesis (Master’s). Federal University of
Santa Catarina. Florianópolis, Brazil.
Detiček, E. and Župerl, U., 2011. An Intelligent Electro-
Hydraulic Servo Drive Positioning. Strojniški vestnik –
Journal of Mechanical Engineering, 57 (5), 394–404.
Furst, F.L., 2001. Sistematização do projeto preliminar de
circuitos hidráulicos com controle de posição (in
Portuguese), Thesis (Master’s), Federal University of
Santa Catarina, Florianópolis, Brazil.
Gomes, S.C.P. and Rosa, V.S., 2003, A new approach to
compensate friction in robotic actuators. In:
Proceedings of the International Conference on
Robotics and Automation, Taipei, Taiwan, Vol. 1, pp.
Guo, J.-C., et al., 2014. Research on Pressure Jump
Characteristics of Valve Controlled Asymmetric Cylinder
System. Research Journal of Applied Sciences, Engineering
and Technology, 7 (12), 2469–2474. doi:10.19026/
ISO 10770-1, 2009. Hydraulic fluid power — electrically
modulated hydraulic control valves — part 1: test methods
for four-port directional flow-control valves. Switzerland:
International Organization for Standardization.
Johnson, J.L., 1996. Design of Electrohydraulic Systems for
Industrial Motion Control. 2nd. Milwaukee: Parker
Kim, M.Y. and Lee, C., 2006. An Experiment Study on the
Optimization of Controller Gains for an Electrohydraulic
Servo System Using Evolution Strategies. Control
Engineering Practice, 14, 137–147. doi:10.1016/j.
Lei, J.-B., et al., 2010. Position Control for Asymmetrical
Hydraulic Cylinder System Using a Single On/Off
Valve. Journal Shanghai Jiaotong University (Sci.),
Springer Verlag, 15 (6), 651–656. doi:10.1007/s12204-
Muraro, I., Teixeira, P.L., and De Negri, V.J., 2013. Effect of
proportional valves and cylinders on the behavior of
hydraulic positioning systems. In: ASME/BATH 2013
Symposium on Fluid Power & Motion Control, 2013,
Sarasota, FL. Bath: ASME, 1–9.
Pereira, P.I.I., Guenther, R., and De Negri, V.J., 2007.
Tracking Control in Hydraulic Actuators Using Slow
Proportional Directional Valves. In: 19th International
Congress of Mechanical Engineering – COBEM. Rio de
Saad, J. and Liermann, M., 2015. Improved sizing of hydraulic
servodrives through inverse simulation approach using
Modelica and modified OpenHydraulics library.
International Journal of Fluid Power, 16 (3), 163–177.
Sun, P., Grácio, J.J., and Ferreira, J.A., 2006. Control
System of a Mini Hydraulic Press for Evaluating
Springback in Sheet Metal Forming. Journal of
Materials Processing Technology. doi:10.1016/j.
Szpak, R., Ramos Filho, J.R.B., and De Negri, V.J., 2010.
Theoretical and experimental study of the matching
between proportional valves and symmetric and asymmetric
cylinders In: 7th International Fluid Power
Conference – 7 IFK, 2010, Aachen-Germany. Aachen:
IFAS, 2010, v 2, 155–166.
Viersma, T.J., 1980. Analysis synthesis and design of
hydraulic servo systems and pipelines. New York:
Elsevier Scientific Publishing Company.