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A hydraulic test stand for demonstrating the operation of Eaton’s energy recovery system (ERS)Wang, Meng (Rachel), Danzl, Per, Mahulkar, Vishal, Piyabongkarn, Damrongrit (Neng), Brenner, Paul 27 April 2016 (has links) (PDF)
Fuel cost represents a significant operating expense for owners and fleet managers of hydraulic off-highway vehicles. Further, the upcoming Tier IV compliance for off-highway applications will create further expense for after-treatment and cooling. Solutions that help address these factors motivate fleet operators to consider and pursue more fuelefficient hydraulic energy recovery systems. Electrical hybridization schemes are typically complex, expensive, and often do not satisfy customer payback expectations. This paper presents a hydraulic energy recovery architecture to realize energy recovery and utilization through a hydraulic hydro-mechanical transformer. The proposed system can significantly reduce hydraulic metering losses and recover energy from multiple services. The transformer enables recovered energy to be stored in a high-pressure accumulator, maximizing energy density. It can also provide system power management, potentially allowing for engine downsizing. A hydraulic test stand is used in the development of the transformer system. The test stand is easily adaptable to simulate transformer operations on an excavator by enabling selected mode valves. The transformer’s basic operations include shaft speed control, pressure transformation control, and output flow control. This paper presents the test results of the transformer’s basic operations on the test stand, which will enable a transformer’s full function on an excavator.
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Modeling And Experimental Evaluation Of An Electrohydraulic Pitch Trim Servo ActuatorOzturan, Ahmet 01 February 2012 (has links) (PDF)
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.
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A hydraulic test stand for demonstrating the operation of Eaton’s energy recovery system (ERS)Wang, Meng (Rachel), Danzl, Per, Mahulkar, Vishal, Piyabongkarn, Damrongrit (Neng), Brenner, Paul January 2016 (has links)
Fuel cost represents a significant operating expense for owners and fleet managers of hydraulic off-highway vehicles. Further, the upcoming Tier IV compliance for off-highway applications will create further expense for after-treatment and cooling. Solutions that help address these factors motivate fleet operators to consider and pursue more fuelefficient hydraulic energy recovery systems. Electrical hybridization schemes are typically complex, expensive, and often do not satisfy customer payback expectations. This paper presents a hydraulic energy recovery architecture to realize energy recovery and utilization through a hydraulic hydro-mechanical transformer. The proposed system can significantly reduce hydraulic metering losses and recover energy from multiple services. The transformer enables recovered energy to be stored in a high-pressure accumulator, maximizing energy density. It can also provide system power management, potentially allowing for engine downsizing. A hydraulic test stand is used in the development of the transformer system. The test stand is easily adaptable to simulate transformer operations on an excavator by enabling selected mode valves. The transformer’s basic operations include shaft speed control, pressure transformation control, and output flow control. This paper presents the test results of the transformer’s basic operations on the test stand, which will enable a transformer’s full function on an excavator.
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Modeling And Experimental Evaluation Of Variable Speed Pump And Valve Controlled Hydraulic Servo DrivesCaliskan, Hakan 01 September 2009 (has links) (PDF)
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.
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