Modeling And Control Of An Electro-Hydraulic Servo Motor Applying Velocity Feedback Control Strategy (original) (raw)

THE VELOCITY CONTROL OF THE ELECTRO-HYDRAULIC SERVO SYSTEM

In general two basic methods are used for controlling the velocity of a hydraulic cylinder. First by an axial variable-displacement pump for controls flow to the cylinder. This configuration is commonly known as a hydrostatic transmission. Second by proportional valve powered by a constant-pressure source, such as a pressure compensated pump, drives the hydraulic cylinder. In this study, the electro-hydraulic servo system (EHSS) for velocity control of hydraulic cylinder is investigated experimentally and its analysis theoretically. Where the controlled hydraulic cylinder is altered by a swashplate axial piston pump or by proportional valve to achieve velocity control. The theoretical part includes the derivation of the mathematical model equations of combination system. Velocity control system for hydraulic cylinder using simple (PID) controller to get constant velocity range of hydraulic cylinder under applied external variable loads. An experimental setup is constructed, which consists of the hydraulic test pump unit, the electro-hydraulic proportional valve unit, the hydraulic actuator unit , the external load control unit and interfacing electronic unit. The experimental results show that PID controller can be achieve good velocity control by variable displacement axial piston pump and also by proportional valve under external loads variations.

Modeling of electro-hydraulic servo-drive for advanced control system design (preprint

The paper describes the synthesis of a mathematical model of the electro-hydraulic servo-drive. Because of the complexity of the electro-hydraulic servo-drive system and the difficulty in determining all systems coefficients, the simplification of the mathematical model is proposed. The model includes different non-linearities such as the friction or the pressure-dependent oil bulk module. The simulation results are presented, and the comparison with the data collected from the real servo drive is discussed. With the proposed method it was possible to choose the values of physical parameters such that the real electro-hydraulic servo-drive is modeled with the accuracy suitable for the fast prototyping and design of the advanced control system.

Modeling and simulation of Hydraulic servo system with different type of controllers

Hydraulic servo systems are characterized by their ability to impart large forces at high speeds and are used in many industrial motion systems. The goal of this paper is to present a mathematical model of a complete hydraulic servo system (solenoid valve, hydraulic valve, actuator, and controller). The model is developed for the system and simulation is carried out with four types of controller namely Proportional (P) control, Proportional-Differential (PD) control, Proportional-Integral (PI) control and PID control. The results of simulation with different controller are discussed and compared.

The modeling and simulation of the servo-hydraulic linear motor

The tendencies obvious today in robot construction relate to flexible automation and mechatronics, i.e. increasing their intelligence level to compensate for nonlinearities and to adapt to distortions. The applied research programme developed by the authors was directed towards optimizing the static and dynamic performance of the linear hydraulic motors with the purpose of investigating nonlinear phenomena occurring while in operation and towards producing a package of numerical simulation software that provide useful information to their design to make them operate at the level of performance that is today required.

Improving the Accuracy of the Electro Hydraulic Servomechanisms by Additional Feedbacks

The paper contains a report on some theoretical and experimental researches aiming to create high accuracy electro hydraulic digital servomechanisms used in high tech applications as actuators, load simulators, fly control systems, dynamic test machines etc. Computational methods, control software, design problems, and experimental validation are shortly presented. The authors developed a new hardware and software solution in order to replace the old generation of two or three stage electro hydraulic servo valves, and to achieve maximum flexibility of the testing programs. By using one derivative feed forward path from the system input and one derivative path from the system output the authors developed a hardware and software configuration that eliminates steady-steady error for step, ramp and parabolic input. The Keythley ADwin PRO DSP high performance industrial computer and ADBasic programming language were used. Also, a configuration with PXI Controller from National Instrument...

On the Dynamic Behavior of Servo-Hydraulic Drives

Nonlinear Dynamics, 1998

A servo-hydraulic drive for position control with a flapper-nozzle type servo-valve is described by a 10th-order, non-linear system of ODEs. This system is partially singularly perturbed. The perturbation stems from the compressibility of the hydraulic fluid and the fast dynamics of some sub-systems of the valve. Center manifold theory in the version due to Fenichel is used to study the

A Study on Electro Hydraulic Servovalve Controlled by a Two Spool Valve

2013

This paper establishes a non linear dynamic model of a two-spool electro hydraulic servovalve. It provides the ability to control flow into and out of valves independently by two separate spools. In this valve there is a flapper/pilot and the boost stage uses two spools instead of a single spool without any feedback wire. The feedback is obtained by pressure. It is likely reduce the valve cost substantially, give higher degree of adjustment and greater safety. In this paper dynamic behavior in respect of armature deflection, spool displacement, chamber pressure, discharge and displacement of the actuator is analyzed using Matlab/Simulink to see if such a low cost servovalve can provide acceptable performance.

Pressure Control of Electro-Hydraulic Servovalve and Transmission Line Effect

2013

The effected of the long transmission line (TL) between the actuator and the hydraulic control valve sometimes essentials. The study is concerned with modeling the TL which carries the oil from the electro-hydraulic servovalve to the actuator. The pressure value inside the TL has been controlled by the electro-hydraulic servovalve as a voltage supplied to the servovalve amplifier. The flow rate through the TL has been simulated by using the lumped π element electrical analogy method for laminar flow. The control voltage supplied to servovalve can be achieved by the direct using of the voltage function generator or indirect C ++ program connected to the DAP-view program built in the DAPcard data acquisition connected to PC, to control the value of pressure in a selected point in the TL. It has been found that the relation between the voltage value and the output flow rate from the servovalve in most of the path is a linear relation. The MATLAB m-File program is used to create a representation state of the mathematical model to find a good simulation for the experimental open loop control test.

Pressure control by the hydraulic nonlinear servovalve

Facta universitatis-series: Mechanical …, 2005

Electrohydraulic servovalves are very often used as commanding devices in the hydraulic systems. For their control many algorithms are developed. This paper gives a control algorithm based upon digital sliding regime. The properties of the proposed algorithm are compared to those of the linear PD controller by computer simulation.