Pump controlled hydraulic actuators offer higher energy efficiency than valve controlled actuators. However, there exists mode switching in pump controlled systems and instability may arise when a single rod cylinder is implemented. This paper examines the problem of system stability in a pump controlled system with single rod cylinders. It is shown that the system dynamics have a stable tendency or an instable tendency corresponding to different cylinder movements. The paper shows system instability can be avoided by controlling fluid leakage, and two applicable methods are presented: physical leakage compensation and virtual leakage compensation, which can be applied depending on applications. Experiments and numerical simulations are presented. Results show that the proposed solutions can maintain circuit stability: physical leakage compensation can be a general approach while virtual leakage compensation offers higher energy efficiency and lower cost, but its applications are limited by some factors.

References

References
1.
Merritt
,
H. E.
,
1967
,
Hydraulic Control Systems
,
Wiley
,
New York.
2.
Berbuer
,
J.
,
1988
, “
Neuartige Servoantriebe mit primärer Verdrängersteuerung
,” Dissertation, RWTH Aachen, Germany.
3.
Lodewyks
,
J.
,
1994
, “
Der Differentialzylinder im geschlossenen hydrostatischen Kreislauf
,” Dissertation, RWTH Aachen, Germany.
4.
Achten
P.
,
Fu
Z.
, and
Vael
G.
,
1997
, “
Transforming Future Hydraulics: A New Design of a Hydraulic Transformer
,” The 5th Scandinavian International Conference on Fluid Power, SICFP’97.
5.
Heybroek
,
K.
,
Larsson
,
J.
, and
Palmberg
.
J.O.
2006
, “
Open Circuit Solution for Pump Controlled Actuators
,” Proceedings of 4th FPNI PhD Symposium, Sarasota, Florida, pp.
27
40
.
6.
Hewett Allan
J.
,
1994
, “
Hydraulic Circuit Flow Control
,” U.S. Patent No. 5,329,767.
7.
Rahmfeld
,
R.
, and
Ivantysynova
,
M.
,
2003
, “
Energy Saving Hydraulic Displacement Controlled Linear Actuators in Industry Applications and Mobile Machine Systems
,” The Fourth International Symposium on Linear Drives for Industry Applications (LDIA03), Birmingham, UK.
8.
Williamson
,
C.
, and
Ivantysynova
,
M.
,
2008
, “
Pump Mode Prediction for Four-Quadrant Velocity Control of Valveless Hydraulic Actuators
,” Proceedings of the 7th JFPS International Symposium on Fluid Power, Toyama, Vol. 2, pp.
323
328
.
9.
Wang
,
L.
,
Book
,
W.
, and
Huggins
,
J.
,
2012
,
“A Hydraulic Circuit for Single Rod Cylinders,”
ASME J. Dyn. Syst., Meas., Control
,
134
(
1
), p.
011019
.10.1115/1.4004777
10.
Yu
,
J.
,
Chen
,
Z.
, and
Lu
,
Y.
,
1994
,
“The Variation of Oil Effective Bulk Modulus With Pressure in Hydraulic Systems,”
ASME J. Dyn. Syst., Meas., Control
,
116
(
1
), pp.
146
150
.10.1115/1.2900669
11.
Shorten
,
R.
,
Wirth
,
F.
,
Mason
,
O.
,
Wulff
,
K.
, and
King
,
C.
,
2007
,
“Stability Criteria for Switched and Hybrid Systems,”
SIAM Rev.
,
49
(
4
). pp.
545
592
.10.1137/05063516X
12.
Wang
,
L.
,
Book
,
W.
, and
Huggins
,
J.
,
2012
, “
Application Singular Perturbation Theory to Hydraulic Pump Systems
,”
IEEE/ASME Trans. Mechatron.
,
17
(
2
), pp.
251
259
.10.1109/TMECH.2010.2096230
13.
Kokotovic
,
V.
,
Khalil
,
H.
, and
Reilly
,
J. O.
,
1986
,
Singular Perturbation Methods in Control: Analysis and Design
,
Academic Press
,
New York, NY
.
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