Fluid Power System Design Research Articles

Compositional Modelling of Fluid Power Systems using Predictive Tradeoff Models

AbstractSystem-level decisions can have a large impact on the success of any design project, including those in the fluid power domain. Regardless of efforts by designers to optimize individual fluid power components, poor decisions at the systems level can lead to poor system performance and unsatisfied design requirements. In this paper, the principles of system-level decision making are applied to the design of fluid power systems. Describe a methodology for modelling fluid power component technology using predictive modelling and data mining techniques in a way that facilitates system-level modelling and decision making is described. This approach is demonstrated on the design of a hydraulic log splitter.

LOAD SENSING WITH ACTIVE REGENERATION SYSTEM

The paper introduces a novel system design of fluid power systems which improves the control and energy use for multiple actuators systems with particular focus on mobile applications such excavators, loaders, tractors. The system hereinafter described is based on a new patented technology [1], the “Load Sensing with Active Regeneration System”. The main idea is to overcome one of the main drawbacks of multiple actuators conventional Load Sensing Systems: while the higher actuator load drives the pump delivery pressure the other active actuators are controlled by the local compensators in a dissipative mode. The goal of the novel architecture is to actively use pressure drops usually wasted in the local compensators and, in case of assistive or overrunning loads, dissipated over control valves.

Applications of modelling and simulation in mechatronics and fluid power system design – education and research

The development within the engineering industry is ever more in the direction of an integration of electronics both on the component level and the system level. This implies improved and more intelligent components with increased functionality at the same time as the variant creation is made in the electronics and software. On the system level the component only constitutes part of the functionality and must be adaptable to different systems. This makes heavy calls on the specification of the concept. In this context control engineering plays a central role, whose well-established methods forms very powerful techniques both in analysis and in synthesis of hydraulic systems. Before control engineering techniques can be applied it is required that hydraulic components and systems can be described in terms compatible with the language used in control engineering, thus, modelling and simulation are needed. The objective of this paper is to show how modelling and simulation and control can be used for analysis and design of mechatronic systems with fluid power actuation. The focus is on system aspects and describes several projects from education and research that utilises the above methods.

Fluid Power System Design for Super-GasTM Fueling Stations

The Composite Fuels Laboratory at the University of Oklahoma has designed and built two new fueling stations to produce and provide an alternative fuel, trademark Super-GasTM to be used for vehicle propulsion. Two fluid power systems have been designed and adapted to accomplish these requirements. Both the fluid power system and the automatic controller control the processes to produce Super-GasTM in a safety and reliable way. This paper will present the fluid power circuits and controller designs for the particular fueling stations. This design system has the capability to either produce the fuel on board the vehicle (BOB) or transfer it to the vehicle tank as a common fueling station. Super-GasTM is a liquid fuel mixture composed of a light hydrocarbon and compressed natural gas and it has somecharacteristics that make it behave as a hydraulic fluid.Super-GasTM made using the bubbling on board type design (BOB) produces 10 Gallon of the mixture in approximately 8 minutes on board the vehicle. A diaphragm pump was used to transfer the light hydrocarbon (LPG). The fast fuel design (FFS) has shown to produce the same amount of fuel in a time range from 5 to 7 minutes, but at any vehicle tank pressure, without reduction in the volumetric efficiency as long the circuit controls the flashing issue. It uses a basic concept of a drive piston pump.The paper will discuss technical hurdles that remain for improving the designs.

Development of a design support tool for fluid power system design

Development of bespoke design methodologies to make them recognizable to designers working in a specific engineering domain is a requirement to making them more acceptable. Application of domain-specific design methodologies by industry will promote the adoption of systematic design, bringing with it the inherent advantages of adopting a systematic approach. This paper examines the development of a domain-specific methodology for fluid power systems, a specialist design discipline within mechanical engineering, and describes the implementation of the methodology within a computerized design support tool. Key technical and methodological features of the design tool are described with specific reference to the knowledge capture and representation processes employed. As such, the need for design theory to be adapted to meet the needs of specific engineering domains within industry is demonstrated.

Knowledge and Reasoning: Issues Raised in Automating the Conceptual Design of Fluid Power Systems

Much progress has been made in the area of computer-aided designer support, but little has been made in that of de-sign automation. Where progress has been made, it has been largely in the analytical aspects of the task (for example, simulation and stress analysis) – tasks for which computers are more suited than humans. Less tractable is automation of the early, conceptual, phase of design, heavily reliant as it is on the expert knowledge of the design practitioner. Em-ulating this computationally is the domain of Artificial Intelligence (AI) and requires a detailed understanding of the nature of the design process (Darlington et al, 1998). This paper discusses some of the issues raised during an investigation in to the automation of the configuration phase of fluid power system design, and identifies some of the hurdles to be cleared before automation, supported by AI, becomes a reality. Two models, developed by the authors, are chosen to illustrate the way in which very different approaches can be taken to automating the same task with an emphasis on the knowledge that is used by designers, which must be acquired and used in automation.

Computational tools for fluid power system design: towards distributed AI and virtual reality

The paper provides an overview of research and development activities in the field of computational technologies for fluid power system design. It aims to identify key concepts and their applications for the development of the next generation of design tools for fluid power system design. Some of the drawbacks in the contemporary procedure for fluid power system design are presented. A new DAI-virtual prototyping approach for fluid power system design is proposed in this paper.

Parameter Sizing for Fluid Power Circuits Using Taguchi Methods

This paper describes the application of Taguchi methods [1-3] to the parameter sizing stage of fluid power system design. Taguchi methods have become almost synonymous with robust design and are used to design systems that are tolerant to the effects of noise factors. Noise factors are defined as anything that causes changes in the functional characteristics or performance of the system that are not controllable. In the hydraulic circuit example used in this paper, these noise factors are assumed to be effects of component failure. The method is therefore being used to select design parameter values such that the resulting circuits exhibit some tolerance to the initial development of faults in the system, which will allow the system to continue to operate for a short period of time without catastrophic failure occurring.

A methodology to automate the design of fluid power systems

This research introduces a methodology to automate the design functions for discrete part automation in manufacturing systems. The methodology is tested by developing a framework to design fluid power control systems. An object oriented modelling methodology, Object Modelling Technique, is used to model the framework, which acts as a road map for system development and future extension. The framework is then verified by means of a computer implementation. A design example is given for illustration.

The Use of Multi-Objective Parallel Genetic Algorithms to Aid Fluid Power System Design

This paper describes the use of parallel genetic algorithms to automate the component sizing stage of the design process. Experiences of applying the method to fluid power systems are discussed and problems encountered are highlighted. Refinements to the standard parallel genetic algorithm for use as a single objective optimizer and its adaptation for use as a method to locate Pareto optimal solutions of multi-objective optimization problems are described. The multi-objective algorithm is used to optimize a mathematical problem and two fluid power circuits.

Role of Simulation in the Design of Fluid Power Systems

Abstract In order to obtain a satisfactory fluid power system, an iterative design process must be employed. This will include circuit selection, component selection and performance assessment. Traditionally, performance assessment has been based on the use of steady state analysis and in some cases, dynamic analysis using linearisation techniques. However, even when this methodology is followed conscientiously systems can still fail to work correctly. Examples are presented which illustrate the type of problem which can arise. It is shown that these problems would have been identified at the design stage if simulation had been used. However, simulation is basically an analytical tool and, in itself, does not indicate directly how a system can be improved. The paper discusses how simulation can be used effectively within the design methodology. It is shown that the successful implementation of simulation depends on the correct interpretation of results together with the creative skills of the designer. The examples indicate that in order to exploit the full power of the analytical software tools available, there is a need for the tools to communicate directly. This requires the development of a standard interface. The likely impact of combining expert system techniques with simulation is discussed.

The Design of Fluid Power Systems Using Analogue Computers

Two important areas in design are formulation and solution of the mathematical model; this paper deals mainly with the latter problem and is primarily concerned with the application of analogue computers to the design of fluid power systems, although much of the work is applicable to general engineering design problems. Before reviewing some typical applications it is first necessary to consider the benefits to be obtained from the use of computers.