Прочитайте и переведите текст. 8. Ответьте на вопросы.

 

Supervisory actions

 

Apart from monitoring, a supervisory system should be capable of taking necessary action to influence operation of manufacturing system.

Changing the machining process parameters is the most common action taken in technological adaptive control systems (a change of tool, for example). When automatic changing of the tool condition in the machine tool is not possible the worn out tool may be automatically replaced by a new one. This is an easy operation for machining centers, because they are equipped with magazines for the automatic changing of tools.

In some cases of disturbances, such as collision between the tool and the production equipment, the automatic supervision in manufacturing system must interrupt the machining process as quickly as possible. An automatic recovery procedure may be applied later. This may involve changes to the process plans and certain types of machining operation may be eliminated.

In a typical system of automatic supervision the results of the manufacturing process are measured and necessary corrections are made to the process. In such a closed-loop system the influences of all disturbances on the measured result of manufacturing may be corrected, but a posteriori (that is, after they have already influenced the result). Another solution is to measure the value of the main disturbance and, knowing how it will influence the result, compensate this influence by appropriate changes in the work of the manufacturing systems. In such a supervisory system, only the influence of measured disturbances may be eliminated or reduced.

The automatic supervision in manufacturing systems may have different structures and work according to different control strategies. This is especially true for on-line manufacturing processes. Because of complicated processes and difficulties in process monitoring, a variety of techniques is often used.

 

8. Ответьте на вопросы.

1) What is the function of a supervisory system?

2) What is the most common action taken in technological adaptive control system?

3) When does the automatic system interrupt the machining process?

4) What may be the results of recovery procedures?

5) What may be corrected in a typical system of automatic supervision?

6) How are the influences of all disturbances corrected in a closed-loop system?

7) What characteristics can you measure in order to correct the process in a closed-loop system?

8) Does an on-line manufacturing process work only according to one control strategy?

 

Подберите пары близких по значению слов из данного ряда.

involve (v), act (v), manufacturing (n), include (v), changing (n), take an action, production (n), replacing (n), supervise (v), take care of.

 

Замените пропуски нужным глаголом (to debug, to wear out, to eliminate, to replace). Поставьте его в пассивной форме.

1) This tool…………; it must be…………by a new one.

2) Certain types of machining operation…………by means of some changes in the process plan.

3) The operation of the tool…………by automatic supervision.

 

Переведите текст письменно со словарем.

 

When designing an automatic supervision and recovery system, there are two factors to be considered:

1) The software must be easy to upgrade, debug and expand;

2) A good knowledge of types of errors that will be encountered must be available, as well as the sensors to be used.

Obviously, one cannot have full knowledge of all types of errors that will be encountered: hence the need to make the software as rich as possible, in order to enable an operator (not a programmer) to add new error which may be foreseeable. It is quite important to construct a software system in which robot and machine programs can be easily optimized, and, ideally, without creating any system downtime.

 

 

Урок 9

 

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