This paper addresses the stability problem of pump controlled asymmetric hydraulic actuators and proposes a physical solution for it. The system under consideration utilizes a shuttle valve to compensate for unequal flow rates due to the asymmetry in the actuator. Possible hydraulic circuit configurations resulting from various valve positions are defined on the load pressure versus velocity plane and a generalized linear model of the system is derived. The investigation shows that there exists a critical load pressure region in which any equilibrium point requiring a partially open spool position is unstable during the retraction of the actuator. A particular valve underlap is proposed in order to avoid the instability and a shuttle valve selection guide is presented. Theoretical findings are validated by both numerical simulations and experimental tests. Results show that the undesired pressure oscillations are removed up to certain actuator velocities with the use of an underlapped shuttle valve.

References

References
1.
Axin
,
M.
,
Eriksson
,
B.
, and
Krus
,
P.
,
2014
, “
Flow Versus Pressure Control of Pumps in Mobile Hydraulic Systems
,”
Proc. Inst. Mech. Eng., Part I
,
228
(
4
), pp.
245
256
.10.1177/0959651813512820
2.
Scherer
,
M.
,
Geimer
,
M.
, and
Weiss
,
B.
,
2013
, “
Contribution on Control Strategies of Flow-On-Demand Hydraulic Circuits
,”
13th Scandinavian International Conference on Fluid Power
(
SICFP2013
),
P.
Krus
, ed., Linköping, Sweden, June 3–5,
Linköping University Electronic Press
, Vol.
92
, pp.
531
540
.10.3384/ecp1392a53
3.
Helduser
,
S.
,
1999
, “
Electric–Hydrostatic Drive—An Innovative Energy Saving Power and Motion Control System
,”
Proc. Inst. Mech. Eng., Part I
,
213
(
5
), pp.
427
437
.10.1243/0959651991540250
4.
Navarro
,
R.
,
1997
, “
Performance of an Electro-Hydrostatic Actuator on the F-18 Systems Research Aircraft
,” Dryden Flight Research Center, Edwards, CA, Report No. NASA/TM-97-206224.
5.
Watton
,
J.
,
2009
,
Fundamentals of Fluid Power Control
,
Cambridge University Press
,
New York
.10.1017/CBO9781139175241
6.
Çalışkan
,
H.
,
Balkan
,
T.
, and
Platin
,
B. E.
,
2009
, “
Hydraulic Position Control System With Variable Speed Pump
,”
ASME
Paper No. DSCC2009-2693.10.1115/DSCC2009-2693
7.
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
, Linkoüping, Finland.
8.
Wang
,
L.
,
Book
,
W. J.
, and
Huggins
,
J. D.
,
2012
, “
A Hydraulic Circuit for Single Rod Cylinders
,”
ASME J. Dyn. Syst., Meas., Control
,
134
(
1
), p.
011019
.10.1115/1.4004777
9.
Rahmfeld
,
R.
, and
Ivantysynova
,
M.
,
2003
, “
Energy Saving Hydraulic Displacement Controlled Linear Actuators in Industry Applications and Mobile Machine Systems
,”
The 4th International Symposium on Linear Drives for Industry Applications (LDIA03)
, Birmingham, UK.
10.
Parker Compact Electro Hydraulic Actuator (EHA)
,
2011
,
Instruction Manual Bulletin HY22-3200A/US
,
Parker Hannifin Oildyne Division
,
New Hope, MN
.
11.
Rahmfeld
,
R.
,
2002
, “
Development and Control of Energy Saving Hydraulic Servo Drives for Mobile Systems
,” Ph.D. Thesis, Technischen Universitat Hamburg-Harburg, Hamburg, Germany.
12.
Hewett
,
A. J.
,
1994
, “
Hydraulic Circuit Flow Control
,” U.S. Patent No. 5,329,767.
13.
Demirer
,
S.
,
Balkan
,
T.
, and
Çalışkan
,
H.
,
2012
, “
Energy Efficient Hydrostatic Transmission Circuit for an Asymmetric Actuator Utilizing a Single Four Quadrant Pump
,” International Patent Application No: PCT/TR2012/000074.
14.
Williamson
,
C.
and
Ivantysynova
,
M.
,
2008
, “
Pump Mode Prediction for Four-Quadrant Velocity Control of Valveless Hydraulic Actuators
,”
7th JFPS International Symposium on Fluid Power
, Toyama, Japan, Vol.
2
, pp.
323
328
.
15.
Wang
,
L.
, and
Book
,
W. J.
,
2013
, “
Using Leakage to Stabilize a Hydraulic Circuit for Pump Controlled Actuators
,”
ASME J. Dyn. Syst., Meas., Control
,
135
(
6
), p.
061007
.10.1115/1.4024900
16.
Akova
,
H. U.
,
2014
, “
Design, Construction and Control of an Electro-Hydraulic Load Simulator for Testing Hydraulic Drives
,” M.Sc. Thesis, Middle East Technical University, Ankara, Turkey.
You do not currently have access to this content.