Hydraulic power systems and actuators play an important role in modern industry because they have many advantages over other technologies with electric motors, high durability, and the ability to produce large force at high speeds. In order to improve the control performance of electro-hydrostatic actuators, the aim of this paper is to propose a novel parallel control strategy based on the self-tuning quantitative feedback theory (STQFT) technique and then applying it to control force and position of a new kind of hydraulic experimental system - the electro-hydrostatic load simulator (EHLS). The EHLS is very useful to test the force or/and position control of electro-hydrostatic actuators (EHAs). The STQFT controller is designed to satisfy the robust criterions based on the QFT technique. Then the parameters of the STQFT force and position controller are automatically tuned online to minimize the system error by using the gradient descent method and speed up convergence. Consequently, the EHLS using the novel controller is able to obtain the force and position control performance with high precision in a wide range of working conditions including perturbations. Experiments are carried out to evaluate the effectiveness of the proposed parallel force and position control method applied to the EHLS system.
RahmfeldR.IvantysynovaM.‘Displacement controlled linear actuator with differential cylinder: A way to save primary energy in mobile machines.’ In Proceedings of the 5th International Conference onFluid power transmission and control, Hangzhou, China, 2001, pp. 316–322.
3.
SuD.WangY.‘Development of electro-hydraulic load simulator with high precision.’ In Proceedings of the 5th International Conference onFluid power transmission and control, Hangzhou, China, 2001, pp. 4–8.
4.
LiY.‘Development of hybrid control of electro-hydraulic torque load simulator.’ASME J. Dynamic Systems, Measmt Control124 (3) (2002): 415–419
5.
MareJ. C.‘Dynamic loading systems for ground testing of high speed aerospace actuators.’Int. J. Aircraft Engng and Aerospace Technol78 (4) (2006): 275–282
6.
GrabbelJ.‘On the control of joint integrated servo actuators for mobile handling and robotic applications.’ In Proceedings of the 1st FPNI-PhD Symposium, Hamburg, 2000, pp. 449–465.
7.
RitoG. D.‘Experimental implementation of a motion-compensated force control in a hydraulic workbench for flight actuators.’ In Proceedings of the International Conference onRecent advances in aerospace actuation systems and components, Insa Toulouse, France, 2007, pp. 51–59.
8.
MareJ. C.MoulaireP.‘Force control of electrohydraulic actuators driving various load mechanical impedances.’ In Proceedings of the 2nd International Fluidtechnisches Kolloquium, Dresden, 2000, pp. 149–162.
9.
AnderssonJ.KrusP.WallaceD.‘Multiobjective optimization of hydraulic actuation systems.’ In Proceedings of ASMEDesign automation Conference, Baltimore, USA, 2000, pp. 11–13.
10.
GuoB.WangM. Y.ZhangJ.‘A dynamic fuzzy neural networks controller for dynamic load simulator.’ In Proceedings of the Fifth International Conference onMachine learning and cybernetics, Dalian, 2006, pp. 375–379.
11.
ChenY. N.LeeB. C.TsengC. H. A.‘Variable-structure controller design for an electro-hydraulic force control servo system.’J. Chin. Soc. Mech. Engrs11 (6) (1990): 520–526
12.
WuG.SepehriN.ZiaeiK.‘Design of a hydraulic force motion control system using a generalized predictive control algorithm.’IEE Proc. Control Theory Applic.145 (5) (1998): 428–436
13.
ConradF.JensenC. J. D.‘Design of hydraulic force control systems with state estimate feedback.’ In Proceedings of the IFAC 10th Triennial Congress, Munich, Germany, 1987, pp. 307–312.
14.
AhnK. K.TruongD. Q.ThanhT. Q.LeeB. R.‘Online self-tuning fuzzy proportional-integral-derivative control for hydraulic load simulator.’Proc. IMechE, Part I: J. Systems and Control Engineering222 (I2) (2008): 81-95 DOI: 10.1243/09596518JSCE484.
15.
YaoB.BuF.ReedyJ.ChiuG.‘Adaptive robust motion control of single-rod hydraulic actuators: Theory and experiments.’IEEE/ASME Trans. Mechatronics5 (1) (2000): 79–91
16.
HorowitzI. M.Quantitative feedback design theory (QFT), (QFT, QFT, Boulder, CO.1992)
17.
LeahyM. B.BossertD. E.WhalenP. V.‘Model-based control with quantitative feedback theory. In Proceedings of IEEE International Conference on’Robotics and automation1 (1990): 1982–1987
18.
ThompsonD.PruynJ. S.ShuklaA.‘Feedback design for robust tracking and robust stiffness in flight control actuators using modified QFT technique.’ In Proceedings of ACC Conference, San Diego, CA, 1999, pp. 754–758.
19.
RoberS. J.ShinY. C.NwokahO. D. I.‘A digital robust controller for cutting force control in the end milling process.’ASME J. Dynamic System, Measmt Control119 (2) (1997): 146–152
20.
NamY.‘QFT force loop design for the aerodynamic load simulator.’IEEE Trans. Aerospace Electronic Systems3 (4) (2001): 1384–1392
21.
NiksefatN.SepehriN.‘Robust force controller design for a hydraulic actuator based on experimental input-output data.’ In Proceedings of the American Control Conference, 1999 vol. 5, pp. 3718–3722.
22.
ThompsonD. F.KremerG. G.‘Quantitative feedback design for a variable-displacement hydraulic vane pump.’ In Proceedings of the American Control Conference, 1997 vol. 2, pp. 1061–1065.
23.
AhnK. K.ChauN. H. T.TruongD. Q.‘Robust force control of a hybrid actuator using quantitative feedback theory.’J. Mech. Sci. Technol.21 (2007): 2048–2058
24.
FerreiraJ. A.SunP.GracioJ. J.‘Design and control of a hydraulic press.’ In Proceedings of the 2006 IEEE Conference onComputer aided control systems design, Munich, Germany, 2006, pp. 814–819.
25.
KudomiS.YamadaH.MutoT.‘Development of a hydraulic master-slave system for telerobotics.’ In Proceedings of First FPNI-PhD Symposium, Hamburg, 2000, pp. 467–474.
26.
NguyenQ. H.HaQ. P.RyeD. C.Durrant-WhytelH. F.‘Force/position tracking for electrohydraulic systems of a robotic excavator.’ In Proceedings of the 39th IEEE Conference onDecision and control, Sydney, Australia, 2000, pp. 5224–5229.
27.
DunniganM. W.LaneD. M.CleggA. C.EdwardsI.‘Hybrid position/force control of a hydraulic underwater manipulator.’IEE Proc. Control Theory Appl.143 (2) (1996): 145–151
28.
SicilianoB.VillaniL.‘Parallel force and position control of flexible manipulators.’IEE Proc. Control Theory Appl.147 (6) (2000): 605–612
29.
D'AzzoJ. J.HoupisC. H.Linear control system analysis and design, (McGraw Hill, New York.1998)
30.
LennartL.System identification toolbox - for use with MATLAB, (The Mathworks Inc., Natick, Massachusetts.1995)
31.
SanadaK.‘A study on a full-electric control system of a hydro static transmission for construction machines.’ SICE Annual Conference, Sapporo, Japan, 2004, pp. 561–565.
32.
EduardE.‘Quantitative feedback design for tracking error tolerance.’J. Automatica36 (2000): 319–326
