• software and machine hardware modules.

- Convertibility. In a reconfigurable system the optimal operating mode is configured in batches that should be completed during one day. with short conversion times between batches. Conversion requires changing tools, part- programs, and fixtures, and also may require manual adjustment of passive degrees-of-freedom.

- Diagnosability. Detecting unacceptable part quality is critical in reducing time in RMS . As production systems are made more reconfigurable and are modified more frequently.it becomes essential to rapidly tune the newly reconfigured system so that it produces quality parts .

Modularity, integrability, and diagnosability reduce the reconfiguration time and effort; convertibility reduces cost. Therefore, these key RMS characteristics determine the ease and cost of reconfigurability of manufacturing systems. A system that possesses these key characteristics has a high level of reconfigurability

Word study

Practice1. Скажите, соответствуют ли данные предложения содержанию текста. Если нет, дайте правильный вариант отпета.

1. The common feature for existing dedicated and flexible systems is their use of reconfigurable hardware and reconfigurable software .

2. The use of rms allows simultaneous reconfiguration of the whole system, the machine hardware and the control software .

3. Machine and control modules are not designed with interfaces for component integration .

4. Conversion requires changing tools, part - programs, and fixtures, and may require manual adjustment of passive degrees-of-freedom .

5. Detecting unacceptable part quality is not critical in reducing time in rms.

6. Modularity, integrability, and diagnosability reduce time and effort, convertibility reduces cost.

7. A system that pocesses these key characteristics has a low level of reconfigurability .

Practice 2. Закончите предложения, выбрав соответствующий вариант в правой колонке.

The common feature for existing dedicated and flexible systems is...

Two technologies that are necessari for reconfiguration ...

These emerging technologies show ...

Reconfigurable systems must be created ...

Machines and control modules are designed ...

Conversion requires

Detecting unacceptible part quality is ...

Therefore, these key RMS characteristics ...

have emerged .

their use of fixed hardware and fixed software .

by using hardware and software modules ,

a trend toward the design of systems with reconfigurable hardware.

changing tools, part programs and fixtures.

with interfaces for component integration .

determine the ease and cost of reconfigurability.

critical in reducing time in RMS .

Practice 3. Образуйте свои предложения . используя словосочетания Practice 2.

Practice 4. Ответьте на вопросы к тексту 4 .

1. What is the common feature for existing dedicated and flexible systems?

2. What tendency do the emerging technologies show ?

3. What is the main purpose of an rms ?

4. Why must reconfigurable systems be designed at the outset to be reconfigurable ?

5. Describe the key characteristics of an rms ?

6. What factors reduce reconfiguration time and effort ?

7. What factors reduce cost ?

Practice 5. Перескажите текст, используя ответы на вопросы к тексту 4 в качестве плана.

Unit 5 Modular structure . Text 5.

1. Прочтите текст, назовите цель создания модульной конструкций рпс. Каким образом достигается взаимозаменяемость станочных модулей?

2. Какие факторы гарантируют лёгкую перестраиваемость ?

3. Насколько важна контролирующая программа в системе рпс ?

4. Какова причина разделения производственных систем на разные уровни?

5. При каких условиях возможна приспособляемость рпс ?

6. Какие типы интерфейсов используются в системе рпс ?

Active vocabulary.

modular structure - модульная конструкция ; changeability - заменяемость; control system - система управления ; interface - интерфейс ; exchangeability - взаимозаменяемость ; to take into account - принимать во внимание ; to update - модернизировать : proper flow - надлежащая подача (снабжение); supervisory program - контролирующая программа; choice - выбор ; machining center - обрабатывающий центр; module dimensions - размерность модуля ; subassemblies - подузлы ; spindle unit - узел шпинделя ; column - консоль ; modular set - набор (ряд) взаимозаменяемых модулей ; to transmit - передавать ; to align - выравнивать .

Reconfigurable manufacturing systems need a modular structure to meet the requirements for changeability, which is provided by a modular system structure. The primary goal in developing RMSs is to develop machine modules which can be quickly exchanged between different manufacturing systems. This exchangeability can be accomplished by equal structure of the machines and the control systems and the standardization of the interfaces combining the modules, which enables a short-term adaptability to market changes by reconfiguration of the manufacturing system.

16

To guarantee easy reconfigurability, not only the physical system must be updated, but also the management and control software must take into account the new characteristics of the plant. This is needed to ensure the proper flow of materials, tools, and information. One of the main reasons for the failure of the early FMSs was the rather problematic supervision of the system. In RMS the supervisory program must be adaptable to different system configurations.

The influence of the modular structure on the reconfigurability of manufacturing systems depends on the choice of the module dimensions. Thus, for example, machine tools can be used as modules in constructing an RMS similar to flexible manufacturing systems (Fig. 1) There are also other examples for manufacturing systems, which are divided into different system levels to enable the exchangebility of modules between workpiece- dependent subassemblies (spindle units, workpiece transport), standard subassemblies (machine column), and the basic machine.