2010 2nd International Conference on Mechanical and Electronics Engineering (ICMEE 2010)
Development of Control System for Two Degree of Freedom Hydraulic Motion Base
Moussa A. Hamdan Electrical and Electronics Engineering Department Nasser Nations University Tripoli, Libya
[email protected]
Mouftah M. Mohamed Department of Control Engineering Higher Institute of Electronic Professions Tripoli, Libya
[email protected]
Abstract- this
paper introduces a mechanism of two degree of freedom hydraulic motion base used for flight simulator. The new system reduces the cost and complicity by using a ball as a base. The performance of the system is then evaluated by using Simscape Matlab Simulink. PI controller is added to improve the overall system response. This designed system has the ability to control a two degree of freedom on ball.
the control system may have some initial conditions. Figure (2) shows the steps of deriving physical system response.
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Keywords-Hydraulic motion base, Matlab Simscape.
I.
INTRODUCTION
Flight simulator training systems is considered to be a complex system and classical methods that had been used for deriving hydraulic systems response are time consuming and might be very difficult for large systems[I]; therefore simulation tools could be used instead of reproducing mathematical models for hydraulic components; These techniques are implemented here to show control system response for expected input signals. The designed system is tested using both Experimental and Simulations tools. Fluid SIM-H is a tool for simulating hydraulic systems. FluidSIM was developed as a joint venture between the University of Paderbom, Festo Didactic GmbH & Co. KG, and Art Systems Software GmbH, Paderbom. FlUID_SIM is used to simulate electro-hydraulic circuit diagrams. The advantage of this simulator is the ability in using ladder diagrams for controlling hydraulic systems. Figure (I) shows the hydraulic circuit diagram of motion base which used ON/OFF controller, ladder diagram is used to control the hydraulic valves directly. The important question is to determine the effect of varied load weight of motion base on the performance of flight simulator. Therefore the mathematical model of motion base must be derived to calculate the response of hydraulic motion base. II.
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Fig.6 Adding PIO controller to the Hydraulic system
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Fig.7 Response of Hydraulic system without PIO controller
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2010 2nd International Conference on Mechanical and Electronics Engineering (ICMEE 2010)
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Table 1 Controller tuning for Hydraulic system controller
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Controller Type
Over shoot
Rise Time
gain
gain
gain
0.5
PI
Zero
8
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0.5
Not
0.4
KP
KI
used
second PI
5%
4
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0.7
15%
3
03
Not
used
second PI
Kd
1
second
0.8
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Figure (8) shows that by introducing the PID controller to the system, and as compared to the graph of figure 7, the delay here is eliminated and also the simulated signal tracks the required signal. An enhanced version of SISO Matlab tool is used to determine the best values of PID terms, Examples of these values are shown in the table below. As shown in figure (7) there is a time delay between simulated movement and the required cylinder movement that results from the effect of loading components. Figure (7) shows tracking control system and it is clear that when making a comparison between simulated movement and the required cylinder movement; there is transient error at cylinder negative movement due to spring and damper model represented as under base movement. From the table above, it is clear that PI controller could improve the response of the system, Also with fine tuning for KI gain in the range between 0.5 to 0.7 could give the best response for the system, on the other hand Kd is not used because the system response is slow and contains delay time as shown in figure (7). VI.
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FIG.8 RESPONSE OF HYDRAULIC SYSTEM WITH PID CONTROLLER REFERENCES [I]
XIN Haitao,WANG Shaoping,JIAO Zongxia, " Multidisciplinary Modeling Technology for Virtual Test and Simulation Platform of Electro-hydraulic Actuator", University of Aeronautics and Astronautics , Beijing, China, 2004
[2]
Meftah Mohamed, " Control system for Hydraulic Pressing Machine", Advanced Research Center Workshop, Libya, 2008.
[3]
Pasadena, CA: Jet Propulsion Laboratory, " SimScape terrain modeling toolkit", National Aeronautics and Space Administration, 2006.
[4]
Graham C. Goodwin!, Stefan F. Graebe, Mario E. Salgado "CONTROL SYSTEM DESIGN", 2000
CONCLUSIONS
Classical methods in simulation hydraulic systems are time consuming and might be very difficult to model for large and complex systems; therefore computer aided design tools is used for simulation hydraulic system, H_Fluid Sim simulator is used for verifYing the motion sequence. But on the other hand; the disadvantage of this simulator is that we can not express the effect of loading weight effect on the system movement. In other way we cannot study the effect of changing load mass with respect the force of cylinder. For all these reasons we use SimScape Matlab Simulink. This paper focused on using a Matlab simulink library which called Hydraulic Simscape; The components of this library depends on using incremental model approach which is used for multi input- multi output system; we tried to improve the response of the system by using PI controller, where tuning of the controller is done by using enhanced version of Matiab SISO tool for making analysis for flight simulator motion base movement.
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