Automated Control

Automated systems are designed to operate under automatic control. Automatic control means they will operate independently or without human intervention. These devices are given appropriate instructions through special programs.

Robots can be classified as computer systems which use automated control. Automated control devices manage themselves once given suitable instructions. Examples of automated control devices include washing machines and microwaves. Automated control devices use a feedback principle. The device must be able to measure or sense a physical quantity such as temperature, position or speed. It uses this data to control itself.

The refrigerator is another example of automated control. A refrigerator has a thermostat that measures the temperature, a controller that compares the set temperature with the temperature in the refrigerator and a compressor motor to remove heat. The controller turns the compressor motor on and off so that the refrigerator maintains the set temperature.

Automation

The application of automated control to industrial processes is called automation. Automation applies machines to tasks once performed by people. It has the ability to perform a set of complicated tasks repeatedly with great accuracy. The development of automation has become increasingly dependent on the use of computer technology. This has resulted in automated systems that have become increasingly sophisticated and complex. Advanced systems represent a level of capability and performance often greater than people, such as in aircraft navigation systems.

Automated Control Systems accept data, process this data and produce data signals or actions to change the operations of another system.

The purpose of an automated control system is to maintain a desired result. It achieves this result by manipulating one or more variables of another system. Example is an air conditioning unit which uses a thermostat to maintain a constant programmed air temperature. This involves:

  • input—the air conditioner reads the room temperature using a temperature sensor
  • process—this reading is compared to the set temperature entered by the user
  • output—signals are sent to turn the thermostat onto adjust the temperature.

Components of an Automated Control System

components of AS.emf.jpg

 Signal conditioners are used to ensure data signals can be understood and measured by a data acquisition device.

Often, control systems need to convert analogue data to digital data (and vice versa).

During this process, the signals may suffer from interference— sometimes referred to as noise.

Signal conditioners help remove any unwanted interference and may be used on both input and output data signals.

DEC Minicomputer

Automated Control System

Robotics Task 7

Create a page called Robotics Task 7 and complete the following.

  1. Research on the issue  "Scientists worry machines may outsmart humans" and answer the following question:

    Do you think automated systems are benefiting humans and improving society in general or are they perhaps moving us towards a technological catastrophe?

  2. Research one control system and write a report. Include the category of control system, list the inputs and outputs, describe the main processes, and explain the role of the computers in the system.

  3. Research the origins of automation and draw a timeline showing the major developments in this area of robotics.

  4. Smart homes use a variety of tools in an attempt to make our lives easier and more organised. Automated systems may also help reduce our impact on the environment. Investigate and present a report on how modern homes are being equipped with a variety of  technological tools that automate tasks and enhance living.

Note: This task is due on Week 7

Historical Perspective

The history of control systems is categorized according to developments in technology. There are four main periods:

  • mechanical and hydraulic
  • direct digital
  • minicomputer
  • microcomputer

Mechanical and Hydraulic

Began during the Industrial Revolution of the eighteenth and nineteenth centuries. The development of control systems at this stage was based on mechanical devices, with inventors having little understanding of how machines could be automatically controlled. Developments in control systems during this period were slow and not usually planned. However, a number of machines, such as looms and lathes, were designed to be self-regulating.

Direct Digital

In 1959, the first digital computer was used to control an automated system. Computers were installed to monitor the control system from a central location using analogue controllers. Development of control systems was still limited by slow and unreliable computers.

During the direct digital period there was a growing need for:

  • more organized methods of controlling systems, which could be achieved by viewing the whole system as dynamic
  • a set of good mathematical models to program computers correctly, which involved developing a better way of controlling computer hardware.

Transistors were developed during this period and built into computers.

Minicomputer

In 1965, the first minicomputer was introduced by Digital Equipment Corporation (DEC). During this period, improvements in computing technology had a direct effect on process control. Computers became extremely reliable and were able to process large amounts of data more quickly. The number of computers used in automated control grew considerably.

Microcomputer

In 1972, the microcomputer appeared and made significant changes to the way computers were used. Programmable controllers were developed and replaced the older styles, which used hard-wired relay logic. This meant that process controllers could be built for control systems.