Unit 21 Grammar: The Infinitive. Split Infinitives Word List:

1. features	особенности, черты, свойства
2. actuator	пускатель, исполнительный механизм регулятора, силовой привод
3. web pages	электронные страницы, сайты
4. power unit	блок питания
5. output	выходные данные, мощность, производительность, отдача, продукция
6. Hydraulic Power Unit HPU	гидравлический энергоблок/ силовой агрегат
7. symbolic representation	схемы, чертежи
8. dialog box	монитор в компьютере
9. weighting sum	сумма с учетом весовых коэффициентов, т.е. с учетом значимости каждого параметра
10. pressure settings	установки (указания), обеспечивающие давление
11. load interaction	влияние нагрузки
12. supply and return lines	вводящие и выводящие (исходящие) линии
13. ballpark figures	близкие к реальным значениям цифры
14. to size the prime mover	оценить размеры первичного двигателя

Expert Systems. Other Useful Features

Output from the prototype pays special attention to the circuit presentation, which includes a symbolic representation, description in text, and an explanation of the choice for a specific configuration. For an actuation circuit, this choice is determined based on corresponding load attributes. For the HPU, the choice is made according to pressure and flow demands of all actuators.

Another convenient feature that enhances the design process is the ability to easily change the HPU specifications or configuration. This is done by suggesting that a user verifies alternative HPUs. These alternatives are described in web pages using graphics and notes on cost, safety, and applicability.

After analyzing the design alternatives, a user can choose to accept or reject design options. Once a selection is made, the prototype updates all system diagrams and incorporates the user’s new choice of HPU. However, this process is reversible; the user can replace the power unit or reselect the previous one. This feature shortens the time to configure diagrams and redefine component lists and gives users freedom of choice to play “what if.”

The program provides multiple choices for actuation circuits, and the user selects the most appropriate for the specific application. To do this, the user defines and ranks a set of application parameters. This process is carried out through a dialog box where the user prioritizes five criteria. Once priorities are established, the prototype performs a weighting sum and establishes all ranking systems as guidelines for the user. This information is also accessible as web pages.

Another important feature is the ability to automatically size the circuits. Once the user defines the numerical parameters for all loads, the program guides the user through a series of steps to define pressure settings and load interaction. Then, the user can rapidly obtain ballpark figures for:

• total flow capacity required

• resonant frequencies of actuation circuits

• power requirement to size the prime mover

• diameters of supply and return lines to optimize flow dynamics, and

• component dimensions (in some cases).

With this tool, users can address the design problem in a hierarchy. First, they define generic mechanical characteristics, which does not require expertise in hydraulics. Next, they evaluate functional alternatives presented by the program, size circuits, and obtain the information necessary to properly select actual components.