Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on November 9, 2007) Vita. Includes bibliographical references.

Industrial applications increasingly require actuators that offer a combination of high force output, large stroke and high accuracy. The ElectroHydraulic Actuator (EHA) was designed by Drs. Habibi and Goldenberg originally as a high-performance actuator for use in robotics. However, it was determined that the EHA had the potential to achieve high positional accuracy. Little research has been performed in the area of high-accuracy hydraulic positioning systems. Therefore, the objective of this study to achieve nano-scale positional accuracy with the EHA while maintaining large stroke and high force output. It was planned to achieve this objective through modification of the prototype EHA and the use of fuzzy control. During this research project, both hardware and control system modifications to the EHA were performed. A high-precision optical encoder position sensor with a 50 nm resolution was mounted on the inertial load to directly measure the position of the load. A number of device drivers were written to interface the MATLAB real-time control environment with the optical encoder and servo motor amplifier. A Sugeno-inference fuzzy controller was designed and implemented in MATLAB. For comparison purposes, a switched-gain controller and a proportional controller were also implemented in the control environment. The performance of the fuzzy controller was compared to the switched-gain controller and the proportional controller in a number of tests. First, the regulatory and tracking performance of the EHA with an inertial load of 20 kg was examined. It was determined in the regulatory tests that the positional accuracy of the EHA with the fuzzy controller was excellent, achieving a steady state error of 50 ± 25 nm or less for step inputs in the range 5 cm to 200 nm. The positional accuracy during the tracking tests was found to be reduced compared to the regulatory tests since the actuator did not have sufficient time to settle to final accuracy due to the timevarying input signals. In all cases, it was found that the positional accuracy of the EHA with the fuzzy controller was significantly greater than with the switched-gain and proportional controllers for both regulatory and tracking signals. Testing with the inertial load eliminated or changed was not performed because the position sensor was mounted to the load, making it unfeasible to alter the load during the time frame of this study. The regulatory and tracking performance of the EHA with an inertial load of 20 kg plus external resistive loads of 90 to 280 N were investigated. It was found that the positional accuracy of the EHA decreased with the application of an external load to 3.10 ± 0.835 µm for a 1 cm step input (90 N load) and 8.45 ± 0.400 µm for a 3 cm step input (280 N load). Again, the positional accuracy of the EHA decreased during the tracking tests relative to the regulatory tests, for the reason stated above. This implies that the positional accuracy of the EHA with a resistive load is in the microscale, rather than the nano-scale as was put forth as the objective of this study. Nevertheless, the positional accuracy of the EHA with the fuzzy controller was found to be significantly greater than with the switched-gain and proportional controllers. It is postulated that the increase in positional error observed during the external load tests was due to an increase in cross-port leakage, relative to the inertial load tests, caused by the pressure differential induced across the actuator by the external load. Methods of reducing the increase in positional error caused by external loads on the EHA remains an area for future study.

Industrial applications increasingly require actuators that offer a combination of high force output, large stroke and high accuracy. The ElectroHydraulic Actuator (EHA) was designed by Drs. Habibi and Goldenberg originally as a high-performance actuator for use in robotics. However, it was determined that the EHA had the potential to achieve high positional accuracy. Little research has been performed in the area of high-accuracy hydraulic positioning systems. Therefore, the objective of this study to achieve nano-scale positional accuracy with the EHA while maintaining large stroke and high force output. It was planned to achieve this objective through modification of the prototype EHA and the use of fuzzy control. During this research project, both hardware and control system modifications to the EHA were performed. A high-precision optical encoder position sensor with a 50 nm resolution was mounted on the inertial load to directly measure the position of the load. A number of device drivers were written to interface the MATLAB real-time control environment with the optical encoder and servo motor amplifier. A Sugeno-inference fuzzy controller was designed and implemented in MATLAB. For comparison purposes, a switched-gain controller and a proportional controller were also implemented in the control environment. The performance of the fuzzy controller was compared to the switched-gain controller and the proportional controller in a number of tests. First, the regulatory and tracking performance of the EHA with an inertial load of 20 kg was examined. It was determined in the regulatory tests that the positional accuracy of the EHA with the fuzzy controller was excellent, achieving a steady state error of 50 ± 25 nm or less for step inputs in the range 5 cm to 200 nm. The positional accuracy during the tracking tests was found to be reduced compared to the regulatory tests since the actuator did not have sufficient time to settle to final accuracy due to the timevarying input signals. In all cases, it was found that the positional accuracy of the EHA with the fuzzy controller was significantly greater than with the switched-gain and proportional controllers for both regulatory and tracking signals. Testing with the inertial load eliminated or changed was not performed because the position sensor was mounted to the load, making it unfeasible to alter the load during the time frame of this study. The regulatory and tracking performance of the EHA with an inertial load of 20 kg plus external resistive loads of 90 to 280 N were investigated. It was found that the positional accuracy of the EHA decreased with the application of an external load to 3.10 ± 0.835 µm for a 1 cm step input (90 N load) and 8.45 ± 0.400 µm for a 3 cm step input (280 N load). Again, the positional accuracy of the EHA decreased during the tracking tests relative to the regulatory tests, for the reason stated above. This implies that the positional accuracy of the EHA with a resistive load is in the microscale, rather than the nano-scale as was put forth as the objective of this study. Nevertheless, the positional accuracy of the EHA with the fuzzy controller was found to be significantly greater than with the switched-gain and proportional controllers. It is postulated that the increase in positional error observed during the external load tests was due to an increase in cross-port leakage, relative to the inertial load tests, caused by the pressure differential induced across the actuator by the external load. Methods of reducing the increase in positional error caused by external loads on the EHA remains an area for future study.

Firing an underwater spark discharge generates an expanding plasma which causes a spherical shockwave to propagate through the surrounding water. The shockwave can have many effects, including resonance effects on bubbles, mechanical destructive effects on solid surfaces and living organisms, and sonochemical oxidative effects on particles and chemical species present in the water. This phenomenon has been shown to improve the efficiency of ink removal in a laboratory flotation deinking cell, while simultaneously decreasing fiber loss. These process improvements are attributed to the sonochemical oxidation of ink particle surfaces, caused by shockwave-induced cavitation. This finding is supported by zeta potential measurements. Sparking was found to reduce the zeta potential of ink particles by up to 20 mV. When sparking was performed during deinking, no effect was found on either ink removal or solids loss. However, when the pulp was pretreated with sparking before flotation, a significant improvement was seen in the brightness gain. Further, fiber loss was decreased by up to 25% in a single flotation stage. The economics of this process are attractive; payback is on the order of three months based on fiber savings alone. Also, at about 1.5 kJ per spark, the power requirements are minimal with respect to the benefit derived.

This contribution presents an operating strategy for a novel valve structure for mobile machines’ working hydraulics which combines the flexibility and energetic benefits of individual metering with the functionality of common primary pressure compensation (IPC). The aim is to set up a system that uses a minimal amount of sensors and simple control algorithms. A control strategy theoretically described in /1/ is modified to facilitate the practical implementation on a mini excavator implement as a test rig. This test rig consists only of components that are currently available off-the-shelf to show that it is possible to develop an individual metering system under these economic restrictions. The novel is more energy efficient than common flow sharing systems but provides the same functionality. The control algorithm is experimentally evaluated in terms of functionality and energy consumption. Simulations show potential for further improvements.

Due to good energy-efficiency of electrohydraulic compact drives a cooling aggregate often is not installed. The operating temperature is governed by the complex interaction between dissipative heat input and passive heat output. This paper targets the simulation of the thermo-energetic behaviour of an electrohydraulic compact drive by means of a lumped parameter model in order to predict the operating temperature. The developed thermo-hydraulic model is validated against measurements utilising thermocouples and a thermographic camera to capture temperatures. The results show, that the presented methodology enables a satisfying accurate prediction of the thermo-energetic behaviour of electrohydraulic compact drives. A further analysis of simulation results is given, highlighting the power losses and heat rejection capabilities of different components. Finally, measures for the improvement of the heat rejection capabilities are studied.

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.

Philosophiae Doctor - PhD / The aim of this study was to design and build an electrohydraulic discharge reactor in such a way that the synthetic immobilized TiO2 nanophotocatalytic components could be integrated, for the production of active species such as OH radicals, ozone and hydrogen peroxide, as a cocktail to clean drinking water without the addition of chemicals. The research objectives include: • To design and construct the different AOP prototypes based on various electrode configurations and compare their operation. • To optimize the discharge parameters and conditions of the best AOP system. • To determine the effectiveness of the best prototype for the degradation of methylene blue as model pollutant. • To compare the designed AOP system with the Sodis method for the disinfection of contaminated river water. • To prepare supported TiO2 nanoparticles via electro spinning, followed by combustion and study the effect on the morphology of TiO2 nanoparticles. • To determine the stability and robustness of composite nano-crystalline TiO2 photocatalysts by sonication • To determine the enhanced effect of combining the composite TiO2 in the AOP system on degradation of methylene blue under the same conditions. • To detect the active species promoting disinfection.

The content of this diploma thesis is proposal of repair, reconstruction of equipment and installation of electrohydraulic regulation of steam turbine. Thesis is given for specific case. At the beginning there is a basic description of repairing turbine. The next part of thesis deals with checking of main turbine parts and recalculation of gland steam. In the following part there is revisional report with repair or exchange suggestions of demaged turbine parts, followed by description of turbine regulation reconstruction. The last part deals with economical evaluation used innovation and recommendations for repairment procedure.

This contribution presents an operating strategy for a novel valve structure for mobile machines’ working hydraulics which combines the flexibility and energetic benefits of individual metering with the functionality of common primary pressure compensation (IPC). The aim is to set up a system that uses a minimal amount of sensors and simple control algorithms. A control strategy theoretically described in /1/ is modified to facilitate the practical implementation on a mini excavator implement as a test rig. This test rig consists only of components that are currently available off-the-shelf to show that it is possible to develop an individual metering system under these economic restrictions. The novel is more energy efficient than common flow sharing systems but provides the same functionality. The control algorithm is experimentally evaluated in terms of functionality and energy consumption. Simulations show potential for further improvements.