الفهرس 
CHAPTER 1: GENERAL INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Electro hydraulic servo systems are non-linear systems and the nonlinearity of these systems arises from compressibility of the hydraulic oil, the complex flow properties of the servo-valve, valve overlap and friction in the hydraulic actuator. Aside from the nonlinear nature of the hydraulic dynamics, there are many considerable model uncertainties, such as internal and external leakages and external disturbances, which cannot be modeled exactly. These nonlinear features need to be discussed and modeled to design high performance controllers and simulating these systems and predicting its behavior with different applications. Therefore, the work in this dissertation focuses on constructing a detailed mathematical model to build a MATLAB SIMULINK model and design an efficient controller. This study proposes a simulation model for electrohydraulic servo motor system and investigates its pressure and flow characteristics. Also, the mathematical model of electro-hydraulic servo is proposed based on force balance equation, voltage equation, and flow equation. Based on the physical parameters and experimental works, the mathematical model is identified and validated for the electrohydraulic servo motor system. The validated model is used to design an adaptive robust controller.
EHS 160 servo mechanism was used to conduct experimental work and the
proposed mathematical model shows a very good agreement with experimental work. Moreover, its performance was improved by applying PI, PID, FLC, FPID, and FSTPID controllers. This leads to better tracking precision and robustness performance compared
to the conventional controllers. The step responses of EHS 160 system with applied controllers were investigated and compared each to others based on controller performance parameters such as rise time, settling time, overshoot amplitude and steady state error. In addition the ability of the controller to reject input and output load disturbances and white noise rejection was investigated. Self-tuned fuzzy PID controller offers the best performance, effort and controllability to the EHS 160 system with 0.087 sec rise time, 0.125 sec settling time, 0.505% overshoot and Zero steady state error. Also, the controller could handle the nonlinearities of the system that are found in the nature of electro hydraulic servo systems and give the best performance when the system is exposed to input and output load
disturbance (50% of load rejection within 0.2 sec) and limited band white noise in the feedback signal.