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1.1 Valve Sizing and  Performance issues

1.2 Spreadsheet  Applicability

1.3 Conventions

        1.4   Spreadsheet

2.1 Data Entry

2.2  Spreadsheet Section 1 – ‘Cylinder and Pressure Supply Details’

2.3  Spreadsheet Section2 – ‘Valve Details’

2.4  Spreadsheet Section 4 – ‘Cylinder Drive Sizing Results’

2.5  Spreadsheet Section 3 – ‘Load and Pipe Details’

2.6  Spreadsheet Section 5 – ‘ Cylinder Drive Position Control Results’

4.1 Application  (Spreadsheet Default) Details

4.2 Selecting Supply  Pressure and Actuator Size

4.3 Valve Sizing

4.4 Mass and Pipeline  Considerations

4.5 Closed Loop Position  Performance

5.1 Component Sizing

5.2 Rules of Thumb for  Position Control Performance

6.1 Cylinder Effective  Mass Calculations

6.2 Three Port Operation

6.3 Pressure Control  Applications

6.4 Digital Controller  Calculations

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Valve sizing and  performance estimation for electrohydraulic servo systems is a necessary

step if the  required performance is to be assured. On some occasions the valve itself

provides a  natural limit to performance, either in terms of maximum flow rates and  therefore

actuator  velocities, or else in terms of the dynamic performance (as described by the  valve

frequency  response). In the later case the valve performance limits the control gain  and  so

also the closed  loop dynamic behaviour and static accuracy.

In other situations the  characteristics of

the actuator and  load being driven

provide a limit  to the closed loop

performance which  will not be improved

even with the  fastest, highest flowing or

most accurate of  servo valves.

Separating these  things out and

optimising  performance but without over

specifying the  valve is not always

obvious, and  generally requires a number

of calculations  to be undertaken. In this

Application Note  a spreadsheet is used

for this purpose.  A minimal amount of

data entry is  required from which the

maximum drive  capabilities and closed

loop static and  dynamic performance is

estimated.