Modeling and experimental evaluation of variable speed pump and valve controlled hydraulic servo drives

Çalışkan, Hakan
In this thesis study, a valveless hydraulic servo system controlled by two pumps is investigated and its performance characteristics are compared with a conventional valve controlled system both experimentally and analytically. The two control techniques are applied on the position control of a single rod linear actuator. In the valve controlled system, the flow rate through the actuator is regulated with a servovalve; whereas in the pump controlled system, two variable speed pumps driven by servomotors regulate the flow rate according to the needs of the system, thus eliminating the valve losses. To understand the dynamic behaviors of two systems, the order of the differential equations defining the system dynamics of the both systems are reduced by using the fact that the dynamic pressure changes in the hydraulic cylinder chambers become linearly dependent on leakage coefficients and cylinder chamber volumes above and below some prescribed cut off frequencies. Thus the open loop speed response of the pump controlled and valve controlled systems are defined by v second order transfer functions. The two systems are modeled in MATLAB Simulink environment and the assumptions are validated. For the position control of the single rod hydraulic actuator, a linear state feedback control scheme is applied. Its state feedback gains are determined by using the linear and linearized reduced order dynamic system equations. A linear Kalman filter for pump controlled system and an unscented Kalman filter for valve controlled system are designed for estimation and filtering purposes. The dynamic performances of both systems are investigated on an experimental test set up developed by conducting open loop and closed loop frequency response and step response tests. MATLAB Real Time Windows Target (RTWT) module is used in the tests for application purposes.


Design and performance analysis of a pump-turbine system using computational fluid dynamics
Yıldız, Mehmet; Albayrak, Kahraman; Çelebioğlu, Kutay; Department of Mechanical Engineering (2011)
In this thesis, a parametric methodology is investigated to design a Pump-Turbine system using Computational Fluid Dynamics ( CFD ). The parts of Pump-Turbine are created parametrically according to the experience curves and theoretical design methods. Then, these parts are modified to obtain 500 kW turbine working as a pump with 28.15 meters head. The final design of Pump-Turbine parts are obtained by adjusting parameters according to the results of the CFD simulations. The designed parts of the Pump-Turbi...
Development of an electrical machines analysis and optimum design software package
Göynük, Yılmaz; Ertan, Hulusi Bülent; Department of Electrical and Electronics Engineering (2008)
In this study, three different programs are developed for the analysis of the three-phase induction motor, single-phase capacitor type induction motor and switched reluctance motor. The programs are developed by using Pascal and C++ programming languages. In the performance calculations of motors, analytical methods are used and these methods are tested for accuracy. These programs have also capabilities to design an optimum motor, which meets a set of performance, material and manufacturing constraints whi...
Universal command generator for robotics and cnc machinery
Akıncı, Arda; Dölen, Melik; Department of Mechanical Engineering (2009)
In this study a universal command generator has been designed for robotics and CNC machinery. Encoding techniques has been utilized in order to represent the commands and their efficiencies have been discussed. The developed algorithm generates the trajectory of the end-effector with linear and circular interpolation in an offline fashion, the corresponding joint states and their error envelopes are computed with the utilization of a numerical inverse kinematic solver with a predefined precision. Finally, t...
Design considerations and performance evaluation of a surge tank for diaphragm pump operation
Özdemir, Şahika; Albayrak, Kahraman; Kayılı, Serkan; Department of Mechanical Engineering (2010)
This thesis is performed to evaluate the design consideration and performance characteristics of a surge tank for a diaphragm pump operation and to evaluate the proper volume and inlet area of surge tank in order to reduce the pulsations of the discharge pressure. An experimental set up is constructed for a three diaphragm positive displacement pump and the experiments are conducted afterwards. The surge tanks having different volumes and the surge tank inlet area configurations are tested in order to achie...
Laboratory investigation of hydraulic efficiency of transverse grates in roads
Özbey, Cumhur; Tiğrek, Şahnaz; Department of Civil Engineering (2015)
In this study, hydraulic efficiency of transverse grated inlet systems to be used in small roads is experimentally investigated. For this purpose, an existing experimental setup in the Hydromechanics Laboratory of METU is utilized. Three sets of experiments are conducted in order to examine the relationship between the total flow rate and the grate efficiency with respect to several parameters. In the first set, the interdependence of the void ratio and grate efficiency is investigated. In the second set of...
Citation Formats
H. Çalışkan, “Modeling and experimental evaluation of variable speed pump and valve controlled hydraulic servo drives,” M.S. - Master of Science, Middle East Technical University, 2009.