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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Formulation and Experimental Demonstration of Design and Control Methods for Efficient Hydraulic Architecture Based on Multi-Chamber Cylinders

Mateus Bertolin (15343399) 04 June 2024 (has links)
<p>Amidst the increasing need to improve efficiency of fluid power systems for off-road vehicles, different architectures have been proposed in literature to reduce system throttling losses. Among the most cited ones, are architectures based on the use of common-pressure rails (CPR), which in some cases have been combined with multi-chamber cylinders to further reduce power losses. This kind of solution appears to be particularly attractive in systems with several actuators with many instances of overrunning loads, such as in earthmoving machines. In this scenario, a basic question arises concerning the maximum amount of energy that can be saved by adding extra pressure rails and/or cylinder chambers. Answering this question can be challenging given that many parameters such as cylinder areas, pressure levels and both actuator and supervisory level controls can affect the results for a given application. This work investigates energy savings potential of different architectures based on the previously mentioned concept. Based on the results of this investigation, a novel architecture combining multi-pressure rails and multi-chamber cylinders is proposed and investigated. The system is sized and simulated for the study case of an excavator. This work addresses controllers design, from the supervisory level power management control to the local cylinder actuation system. In addition, special care is taken in the area selection of the multi- chamber cylinder, with factors such as manufacturing cost and reliability being considered. The proposed design procedure allows the design of compact and efficient three-chamber cylinders on a wider range of applications. Results show the potential for power consumption reduction of up to 31% when compared to state-of-the-art machines available in the market. Additionally, the proposed cylinder design optimization allows a reduction of up to 25% in cylinder weight when compared to other design methods for multi-chamber cylinders. Within this scope, an experimental setup is designed for proof of concept of the proposed hydraulic circuit and cylinder control methods, with laboratory tests validating the feasibility of the proposed system. Test results demonstrated the ability of the proposed controller in efficiently controlling pressures within the actuator, while delivering stable speed tracking performance. Experiments also demonstrated the system capability in recovering energy and validated the expectation of obtaining hydraulic actuation with low pressure drop across control valves.</p>

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