Hydraulic Component Design Library
Rev 9 – November 2009
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TABLE OF CONTENTS
1. Introduction (1)
2. Tutorial examples (3)
2.1. Constructing hydraulic check valves using HCD (3)
2.2. Constructing a hydraulic jack using HCD (10)
2.3. Constructing spool valves (15)
2.4. 3-position 3-port hydraulic directional control valve (18)
2.5. Hydraulic jack with moving body (23)
3. A Few General Rules (25)
3.1. Introduction (25)
3.2. Causality (25)
3.3. Use of special facilities for setting parameters (26)
3.4. Use of the mass dynamics blocks (26)
3.5. Setting chamber length at zero displacement (26)
3.6. Major reconstructions (27)
Using the
HCD Library
1. Introduction
HCD stands for Hydraulic Component Design (previously named Hydraulic AMEBel -which stands for AME Sim asic e lement ibrary-). You can use the HCD library to construct a submodel of a component from a collection of very basic blocks. HCD greatly increases the power of AMESim but it is a good idea to be thoroughly familiar with the standard AMESim submodels before you start using HCD.
Why was it necessary to create this library? This question will be answered in this section. After this, five examples of the use of HCD are presented. In the last section a few general rules are established to enable you to use HCD effectively.
The first four examples are concerned with absolute motion. The majority of applications of HCD that you will use will likely fall into this category. The fifth example is concerned with relative motion. It is recommended that you reproduce the first FOUR examples using AMESim.
When you use AMESim, you build a model of an engineering system from a collection of components. For these components AMESim originally used graphical symbols or icons based on standard representations (such as ISO symbols for hydraulic components). For an engineer working in a particular field, this makes the final system sketch look very standard and very easy to understand. However, there are two problems associated with this approach:
diversity of components,
diversity of skills.
The diversity of components problem can be stated quite simply: ‘no matter how many components you have, there are never enough’. As an example think of a hydraulic jack. Here are some possibilities
the jack can have one or two hydraulic chambers,
it can have one or two rods,
it can incorporate one, two or zero springs.
This gives 12 combinations and each would need a separate icon. Behind each icon must be at least one submodel. For many AMESim icons, one submodel is enough. In this case, we would have 12 submodels. If we consider telescopic jacks, the number of possibilities doubles. Sometimes it is useful to allow different causalities on the ports. With all the possible combinations of causality on ports there could be well over a hundred submodels of jacks.
It is not possible to provide huge numbers of icons and submodels within the standard AMESim libraries. Hence only the more common component icons and submodels are provided. The expert AMESim users can of course create extensions by using AMESet to add both new icons and new submodels but at this point we encounter the second diversity problem.
What skills are necessary to produce good submodels of components in AMESim or any other software? Here is a list:
an understanding of the construction and operation of the component;
an understanding of the physics governing the operation of the component;
an ability to translate the physics into a mathematical algorithm to determine the outputs
of the submodel from its inputs;
an ability to translate this algorithm into a working piece of code.
