HYDRAULIC COMPONENTS STANDARD MATHEMATICAL MODELS FOR APPLICATION ENGINEERS

ABSTRACT
In order for the hydraulic component manufacturers to compete in the very tough
market, they must spend every effort to improve the characteristics of their
components. End users of hydraulic components have different interests depending
on the application e.g. cost, dynamics, efficiency, life time, operational conditions,
sensitivity to contaminations, noise, etc. Therefore, R&D sections at the hydraulic
component manufacturers are working day and night to investigate these issues
through developing detailed models. In some cases, probably several models are to
be developed for the same component where each model is dedicated to handle one
prospective, e.g. one model for dynamic response, second model for thermal
analysis, third model for stress analysis, etc.
Detailed models like these usually include dimensional parameters, operating
conditions and fluid properties. Most of these design parameters are known to the
component developer and considered critical and even classified info in the high tech
industry. Additionally, some of these design parameters may require to be carefully
assumed because it is not 100% known, e.g. viscous friction coefficients, leakage
coefficient, etc.
These expensive component-level models that are developed at the manufacturer’s
site may be dedicated for specific component/size/ brand and are not applicable for
other component/size/brand. Also it may be developed using software packages that
are not available for public.
System-level design is a totally different environment. First of all, system designers
have no access to all the critical design parameters of each component and it will be
tough for them to run after every unknown design parameter in every component.
Secondly, system designers are mostly interested only in the static and dynamic
characteristics of each component regardless the inside construction of the
component. System designer can mathematically model simple systems by a set of equations to be solved instantaneously. Part of the problem to follow such approach is that if the system layout is changed, the whole set of equation will be changed too. Therefore, system designer is mainly looking for more generic models that are flexible enough to be used repeatedly for similar components. In the past decade, a number of software packages were found in the market. These packages contains library out of which the user may grab premade models for hydraulic components to use in a system design. These software packages may give access to the user to see the mathematics behind the model, but not give access to change the way the models have been built. Recently a committee has been formed to formulate standard mathematical models
for various fluid power components. The main objective is to standardize the
mathematical models to facilitate the broader use, teaching and understanding of
fluid power systems in solving application-specific problems. This will raise the
technological level of the fluid power industry.
The purpose of this lecture is to update theaudience about the mission of the  
committee, give a case study and recruit senior faculty to join the committee as a
members or observers.