Modelling and experimental evaluation of an electrohydraulic pitch trim servo actuator

Özturan, Ahmet
The pitch trim actuator is a hydraulic powered electro-mechanical flight control device of UH-60 helicopters which converts a mechanical input and an electrical command into a mechanical output with trim detent capabilities. In this thesis study, pitch trim actuator is investigated and a mathematical model is developed. From these mathematical equations, the actuator is modeled in MATLAB Simulink environment. While constructing the mathematical model, pressure losses in hydraulic transmission lines and compressibility of hydraulic oil are considered. To achieve a more realistic model for valve torque motor, particular tests are carried out and the torque motor current gain and the stiffness of torque motor flexure tube and the flapper displacement are obtained. Experimental data to verify the Simulink model is acquired with KAM-500 data acquisition system. A test fixture is designed for acquiring the experimental data. This test fixture can also be used to test the pitch trim actuator during depot level maintenance and overhaul. To verify the consistency of Simulink model, acquired experimental data is implemented in Simulink environment. The output of Simulink model simulation and the experimental data are compared. The results of comparison show that the model is good enough to simulate the steady state behavior of the actuator.


Modelling and simulation of power steering system for agricultural tractors
Gültekin, İdil İlke; Cömert, Samet A; Erkal, Gül; Ünlüsoy, Yavuz Samim; Balkan, Raif Tuna (null; 2016-10-11)
This paper presents the development of models for the hydraulic and mechanical parts of the power steering system of an agricultural tractor. The hydraulic model is built using the component blocks from the Fluids toolbox of the Matlab/Simulink platform. The hydraulic part of the model is then integrated with the mechanical model of the front axle developed using the SimMechanics toolbox. The modeling procedure of the hydraulic system, containing a steering control unit, is described. The overall model allo...
Yerlikaya, Umit; Balkan, Raif Tuna (2017-10-13)
Electromechanical actuators are widely used in miscellaneous applications in engineering such as aircrafts, missiles, etc. due to their momentary overdrive capability, long-term storability, and low quiescent power/low maintenance characteristics. This work focuses on electromechanical control actuation systems (CAS) that are composed of a brushless direct current motor, ball screw, and lever mechanism. In this type of CAS, nonlinearity and asymmetry occur due to the lever mechanism itself, saturation limit...
Modeling and experimental evaluation of variable speed pump and valve controlled hydraulic servo drives
Çalışkan, Hakan; Balkan, Raif Tuna; Department of Mechanical Engineering (2009)
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 reg...
Optimal Design of a Miniature Quad Tilt Rotor UAV
Kahvecioglu, Ahmet Caner; Alemdaroglu, Nafiz (2015-06-12)
This paper describes the design procedure of a convertible miniature (mini and micro) quad tilt rotor unmanned air vehicle (UAV), which has about 2 meters of wing span, one hour of mission time and 5 kilograms of total weight. The aircraft is driven by four brushless direct current motors, and the structure of it completely made of composite materials. When the wing and tail of the aircraft are dismounted, it operates as a quad- rotor with tilting rotors. The aircraft is planned to carry a gimbal camera wei...
Experimental investigation on sharp crested rectangular weirs
Şişman, H. Çiğdem; Altan Sakarya, Ayşe Burcu; Department of Civil Engineering (2009)
Sharp crested rectangular weirs used for discharge measurement purposes in open channel hydraulics are investigated experimentally. A series of experiments were conducted by measuring discharge and head over the weir for different weir heights for full width weir. It is seen that after a certain weir height, head and discharge relation does not change. Hence a constant weir height is determined. For that height; discharge and head over the weir are measured for variable weir width, starting from the full wi...
Citation Formats
A. Özturan, “Modelling and experimental evaluation of an electrohydraulic pitch trim servo actuator,” M.S. - Master of Science, Middle East Technical University, 2012.