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This paper focuses on the research and analysis of a typical large inertia electro-hydraulic position control system using single-rod cylinder. Firstly, the mathematical models of the main components such as the electro-hydraulic servovalve and cylinder are described. Then the model of the whole control system is established based on that. The control method of the system is the conventional PI algorithm. In order to find out the proper PI parameters, the computer simulations are performed. Finally, experiments are carried out to validate the proposed method. The experimental results show that the proposed model and control method are effective.

This paper describes a methodology for simultaneous identification of fault parame-ters and mode switching events for hybrid systems. The method is developed based on the notion of Global Analytical Redundancy Relations (GARR) from the bond graph model of the hybrid system. A unified formula with mode change time sequence and initial mode coefficients (IMC) is derived to represent the mode switching. It employs Genetic Algorithm (GA) to search for fault parameters and mode switching time stamps. Fault parameters, mode switching time stamps and all IMC are encoded into one chromosome as a potential solution of the identification process. GARRs are used as a fitness index in GA search. An electro-hydraulic system of vehicle is studied to illustrate the efficiency of the proposed algorithm.

The synthesis control of force and position in electro-hydraulic servo system has been applied to some special occasions. Analyzed a typical system which adopted this kind of control algorithm. Applying unchanged structure theory, the compensated transfer function has been deduced, the compensated state-space model is presented. Considering the synthesis control should meet the requirement to force and position at the same time , introduced the linear quadratic performance fonctionelle, the optimized control formula of the synthesis control of force and position on total state feedback has been deduced. The simulation results proved that the compensated state-space model has more superior performance.

The axial misalignment of steel belt is inevitable outcome of the speed-change way of metal V-belt type CVT. The axial misalignment of steel belt can result in the slipping and addition abrasion between the belt and pulley L and consuming extra energy, which will influence the transmission performance.On the basis of the analysis of the belt misalignment of the metal V-belt CVT, the reason of the belt misalignment has been discussed. In order to control the misalignment, an electro-hydraulic control system has been designed. After deeply analyzing the structure and principle of the electro-hydraulic control system, the belt misalignment control strategy for metal belt CVT has been put forward, and the mathematical model of the electro-hydraulic control system has been established. Being varieties of the working situation of car and the non-linearity of the electro-hydraulic control system, A Fuzzy PID algorithm has been designed. Then the simulation and experiment of the belt misalignment has been conducted, the results showed that the electrohydraulic control system could remarkably eliminated the belt misalignment, improved the dynamic performance of the metal V-belt CVT, reduced the belt's abrasion, prolonged the belt's using-life. (5 pages)

Now the modeling and collaborative simulation of electro-mechanical system is one of hotspots for studies and applications. In this paper, ADAMS, AMESim and Simulink software are selected as the software environment for collaborative simulation of electro-hydraulic system. The functions and characteristic of these softwares are introduced. The hydraulic-driven lift system is taken as an example, the basic sketch for modelling and collaborative simulation of electro-mechanical system based on the interfaces is discussed, and the realization methods of collaborative simulation using the interfaces are studied. The research is of significance for the collaborative simulation and optimization of complex electro-mechanical system.

Regenerative brake system (RBS) has been one of the most important systems which can improve vehicle economy efficiency along with the development of clean energy vehicle (CEV), such as HEV (hybrid energy vehicle) and FCV (fuel cell vehicle). This paper provides a simple and reliable Electro-Hydraulic Parallel Brake System (EHPBS) based on the conventional vehicle brake system. This EHPBS can implement parallel distribution strategy between regenerative brake force and the hydraulic brake force thereby achieves kinetic energy regeneration. Because of the difficulty and the danger of brake system experimentation, this paper tests the EHPBS in HILS (Hardware-In-the-Loop Simulation) environment, and the experiment data prove the system to be available and effective.

Using the biological immunology principle unifies the neural network and the immunity algorithm to form the immunity neural network, which is applied to electro-hydraulic servo valve breakdown diagnosis. The result indicated that, the immunity neural network can identify many kinds of failures pattern recognition accurately by the smaller network scale, and has the high efficiency, good fault-tolerant performance and formidable auto-adapted ability.

This paper presents a methodology for choosing the optimal PWM method for the 3-phase automotive drives applications for electric and electro-hydraulic power steering. It shows how some of the automotive specific requirements transpose to PWM requirements. A system overview with motor and control principles has been presented, followed by the method of power loss calculations based on datasheet parameters and, after that, an overview of the PWM Methods is given. These Methods are compared based on: power loss minimisation, usage of the battery voltage, quality of output current and noise emission minimisation.

Sufficient conditions for the robust stability and stabilizability of linear continuous-time polytopic systems are proposed in this paper. These conditions are based on a parameter-dependent Lyapunov matrix obtained from the feasibility of a set of matrix inequalities defined at the vertices of polytopic systems. Noting that an electro-hydraulic servo system can be modeled as a linear continuous-time polytopic system, the controller derived from the proposed condition is applied to the control of this system. A numerical example demonstrates that this method has satisfactory performance.

A practical solving method for nonlinear blending system (NBS) based on hierarchical fuzzy control is proposed. The solving method can reduce the required rule base size by using the hierarchical fuzzy control, and increase the robustness and response performance of NBS. In order to confirm, the proposed solving method is used in ethanol gasoline blending system in tank farm of PetroChina and SINOPEC. The control precisions meet the requirement of distributing and blending. It avoid that the electro hydraulic valves regulate frequently by using this method. The cost of NBS has been down. The system and approach proposed is applicability in other petroleum chemical control system.

The position tracking control of a missile electro-hydraulic servo system is studied. Since the dynamics of the system are highly nonlinear and have large extent of model uncertainties, such as big changes in parameters and external disturbance, a design method of sliding mode control (SMC) using recurrent fuzzy neural network (RFNN) is proposed. First a SMC system, which is insensitive to uncertainties including parameter variations and external disturbance, is introduced. Then, to overcome the problems with SMC, such as the assumption of known uncertainty bounds and the chattering phenomena in the control signal, an RFNN is introduced in conventional SMC. An RFNN bound observer is utilized to adjust the uncertainty bounds in real time. Simulation results verify the validity of the proposed approach.

The paper contains a summary of the experimental results of a long-term research program aiming to design, manufacture, setup and full industrial test a new type of electro hydraulic digital speed governor for Kaplan water turbines. Computational methods, control software, design problems, and mainly performance validation are shortly presented. The work represents the second part of a final research report on the modern electro hydraulic speed control of the power units.Copyright © 2007 by ASME

In this article, a degradation assessment model has been proposed for electro-hydraulic shift valve in power-shift steering transmission. Our work is motivated by the failure mechanism of abrasive wear with a mathematic model. Abrasive wear will consecutively enlarge the clearance between the friction pairs. It is an overwhelming wear mechanism in the degradation of shift valve within serious contaminated fluid. Herein, a mathematic model is proposed by considering particle morphology and abrasion theory. Such model has been verified for its applicability and accuracy through comparison between the theoretical and experimental results.

In this paper we attempt to apply some neural networks based methods in order to solve a control benchmark problem. The goal is to control an electro hydraulic velocity servomotor system. Firstly, some ordinary neural networks have been employed as a controller and simulation results are shown. Secondly, the FEL method is employed and the advantages are mentioned. Both "Dynamic" and "CMAC" neural networks are employed in FEL scheme.

Because some parameters are uncertain in loading system of electro-hydraulic load simulator, the controller designed by classical control theory has disadvantages such as dependency on model and weak robustness. Robust controller is designed by mixed sensitivity H? approach through choosing suitable weighted functions. It's solved through linear matrix inequality algorithm. It's testified by experiments that robust controller can satisfy robust stability and robust performance when spring stiffness changes. It also can eliminate superfluous force and improve passive loading performance with compensation of structure invariance principle.

This paper presents a novel robust sliding mode controller with fuzzy tuning for Stewart platform servo system, which suffers from high nonlinear dynamics and serious load coupling among channels. The controller consists of an equivalent control to assign desired dynamics to the closed-loop system, a switching control to guarantee a sliding mode, and a fuzzy control to enhance fast tracking and attenuate chattering. To verify the potential and effectiveness of the proposed controller, simulations and experiments are made. The results demonstrate its strong robustness against a large range of parameters variations and load disturbance and its capability of restraining the serious load coupling among channels and improving the trajectories tracking performance.

This paper describes an Electro-Hydraulics Laboratory (EH Lab) at the University of Missouri - Rolla (UMR), which was recently established with a gift from Caterpillar Inc. The goal of this laboratory is to provide students the opportunity for hands-on experience with signal processing, dynamic modeling, and real-time control of industrial-grade electro-hydraulic systems. Unlike most comparable educational laboratories, nearly all of the components used in this laboratory were originally intended for industrial use, yielding a much more real-world experience for students. The laboratory utilizes the xPC Target software for rapid prototyping and execution of real-time data acquisition and control systems using Simulink. Several laboratories, as well as a course project, that utilize the EH Lab are presented.Copyright © 2006 by ASME

This paper proposes a dynamic model of an electro-hydraulic three point hitch for farm tractors. The modeling technique is based on the Hamiltonian system framework and on power-port interaction between subsystems. The model allows fast and precise simulations and therefore can be used for the development and the validation of control strategies by simulations and hardware in the loop experiments. The proposed model has been validated comparing the simulation results with experimental measurements.

The paper analyzes the merits and drawbacks of the genetic algorithm and BP neural network, combines with the improved genetic algorithm and BP neural network to obtain a new algorithm. The new algorithm is used in the fault diagnosis of electro-hydraulic servo valve and justified its validity, accuracy and rapidity by experiment. The BP algorithm, the conventional GA-BP algorithm and the improved GA-BP algorithm are compared by the data of experiment. It is shown the superiority of the improved GA-BP algorithm in the fault diagnosis field.

A new type of piezoelectric direct drive electro-hydraulic servo valve is developed in this paper. Multilayer piezoelectric actuator is used as the electricity-machine converter in this new electro-hydraulic servo valve, which makes the electro-hydraulic servo valve system have higher dynamic and steady performance. Because the system exists complicated nonlinearity and uncertainty, the conventional control method cannot meet the speed and precise requirements for positioning. An improved fuzzy control method with self-adjusted function is designed and implemented. Because of eliminating the undesirable nonlinear effects, the proposed method demonstrates substantial improvements in the dynamic and steady characteristics of the system. The experimental results illustrate the effectiveness of the proposed control method.

Direct methanol fuel cells (DMFCs) are an attractive fuel cell choice option, particularly because of the capability to use liquid fuel without need for processing. The phenomenon of methanol crossover, however, substantially reduces cell power output and efficiency. The present work shows the benefits of periodically pulsed fuel supply and current load on the performance of a DMFC. It is determined that the enhanced performance resultant from such electro-hydraulic (EH) pulsing is realized due to temporary, cyclic mitigations of methanol crossover (as well as unstably high voltages given high frequency electronic pulsing).Copyright © 2004 by ASME

The paper aims to investigate two advanced methods used in fault diagnosis of electro-hydraulic (EH) control systems. The theoretical background of the neural network method and model-based approach are presented and the implementation of these methods is summarised with procedures in easy steps to follow for application. The pros and cons of these methods are also analysed based on fault detection capability. It is concluded that a combination of the neural network method and the model-based approach will be beneficial.

An electro-hydraulic system (EHS) that consists of a hydraulic pump driven by brushless DC motor is monitored for pump cavitation using feedforward fully connected artificial neural networks. The effectiveness of monitoring is demonstrated in a laboratory environment using open software architecture (OSA) framework.