1. Slide 1 Standard Grade Computing Automated Systems

2. Slide 2 Standard Grade Computing Why Use Automated Systems? These are systems in which computers are used to control machines and equipment. They are used because: (a)they are fast. Computers react in fractions of a second. Machines under their control will act and react much quicker than ones controlled by humans. (b)they can operate in dangerous environments. Eg North Sea oil platforms, chemical factories, nuclear power stations. (c)they can cope with repetitive tasks without making mistakes or slowing down.

3. Slide 3 Standard Grade Computing (d)they are accurate. Automated systems follow instructions precisely and can thus guarantee 100% accuracy. (e)they are efficient. Because they are accurate there is no waste and thus no time lost mending errors. Credit (f)they are adaptable (can be used for different tasks). Automated systems can be designed to be flexible and handle a range of different tasks eg spray painting, welding or carrying.

4. Slide 4 Standard Grade Computing Types of Automated systems (1)Robots What Is A Robot? A robot is a machine which is controlled by a computer. Robots are FLEXIBLE because they can be REPROGRAMMED to perform different tasks. A dedicated machine can only do ONE TASK.It is NOT REPROGRAMMABLE. eg A Washing Machine

5. Slide 5 Standard Grade Computing Robot Anatomy Shoulder Elbow Wrist End Effector Waist

6. Slide 6 Standard Grade Computing Interface Robots are connected to a computer by a device called an INTERFACE. The interface makes sure that the right messages are sent between the computer and the robot in a form that they can both understand. INTERFACE

7. Slide 7 Standard Grade Computing Credit End Effector Tool attached to the end of a robot arm. The part that carries out the function of the robot. Example: Welding electrode, suction cup, paint spray, gripper, electromagnet. LOOK UP - ‘Standard Grade Computing Studies’ p129 to see what some of these look like

8. Slide 8 Standard Grade Computing Stationary robots They are fixed in one spot to perform their task. Eg a stationary robot arm stationed at the side of a conveyor belt welding parts onto a car body. Mobile robots They are fitted with wheels or tracks and are powered by electric motors. A mobile robot might be used for transporting dangerous chemicals inside a chemical plant.

9. Slide 9 Standard Grade Computing (ii) Magnetic Guidance Systems An electric cable which gives off a magnetic field is set in the factory floor. The robot is fitted with magnetic sensors which can detect a magnetic field and feed the data to the control computer. The computer guides the robot along the correct path. Sensors Buried Wire Magnetic Field

10. Slide 10 Standard Grade Computing There are two ways to make robots mobile: (i) Light guidance system The path for the robot is set by a white line painted on the factory floor. A light source shines a light directly onto the white line. Light Sensors on either side of the light source detect and measure the amount of light reflected off the floor. If the amount of reflected light detected is uneven then robot is guided back onto the correct path. Light Sensor Lamp Light Sensor

11. Slide 11 Standard Grade Computing Credit Degrees of Freedom The number of different ways a robot arm can move. Example: 2 3 4 1 Shoulder Elbow Wrist End Effector Waist

12. Slide 12 Standard Grade Computing YAW, PITCH and ROLL are the terms used to describe the different types of movement made by the robot arm.

13. Slide 13 Standard Grade Computing Robots can be controlled by 1. A Computer Program The program is usually in a high level language. New programs can be written OFF-LINE. The advantage of this is that the robot is still working while the program is written. The robot can then be stopped and re- programmed to perform different tasks.. 2. Lead-through programming The human operator will lead the robot through the task that has to be done. The computer will store the movements of the robot performing the task. 3. Remote control Using a joystick/keypad a human can control the robot arm and record each movement of the arm.

14. Slide 14 Standard Grade Computing Control of Automated Systems Automated systems are controlled by instructions (software) stored in and sent out from a computer system. There are two types of control which can be used on any automated system: 1.Open loop In an open loop control system the processor is instructed to perform a task and it does not stop until it has finished the task. Example:dishwasher, washing machine etc.. ComputerMachine control information

15. Slide 15 Standard Grade Computing Open loop control systems In an open loop system the processor is instructed to perform a repetitive task and doesn’t stop until it has finished.

16. Slide 16 Standard Grade Computing More open loop control systems Washing Machine Toaster

17. Slide 17 Standard Grade Computing 2. Closed loop A closed loop control system uses one or more sensors to detect what is going on around it, and it can change what it’s doing depending on the information it gets from the sensors known as feedback. Computer sensors detect action machine takes action Decision feedback

18. Slide 18 Standard Grade Computing More closed loop control systems There are many different types of sensor that can be used for burglar alarms. All of them measure whether a person has entered or is about to enter a room. The most popular types of sensor for burglar alarms are door switches and infra-red detectors. Burglar Alarms

19. Slide 19 Standard Grade Computing More closed loop control systems Door switches are fitted somewhere around the edge of the door. When the door opens, the switch signals to the computer, which sounds the alarm. Burglar Alarms Infra-red detectors detect invisible infra-red light. All warm objects give out infra-red light. The detector constantly looks for any movement of infra-red light. When a burglar moves in front of the sensor it signals to the computer which sounds the alarm.

20. Slide 20 Standard Grade Computing More closed loop control systems Some greenhouses have computer- controlled equipment for growing crops such as strawberries all year round. Greenhouses Sensors measure the temperature inside the greenhouse. If the temperature is too high, the machine opens the windows. If the temperature is too low, the machine closes the windows and may switch on a heater. Watering, feeding and lighting can also be controlled automatically.

21. Slide 21 Standard Grade Computing Sensors Sensors can provide information to a robot about its surroundings. This allows the robot to respond to the changing environment. Example:A robot picking up an egg will not crack it if it can monitor the pressure applied to the egg.

22. Slide 22 Standard Grade Computing Types of sensors: (a)Pressure Sensors - used to sense pressure when handling objects, bumpers on mobile robots. (b)Heat Sensors - used in places of extreme temperatures eg. furnace or refrigeration plant. (c)Light Sensors - used to find light or lack of it. (d)Optical Sensors - it is possible to identify very simple objects by ‘sight’ eg. squares. (f)Magnetic Sensors - used to detect electromagnetic field around an underground cable for navigation.

23. Slide 23 Standard Grade Computing Sensors are devices which detect and measure levels of energy. Such measurements are known as analogue, because they vary continuously. However, computers are digital devices. 0 1 1 0 1 0 0 1 0

24. Slide 24 Standard Grade Computing A sensor converts the analogue signal into an electrical signal. This varying electrical signal is converted into digital data by the interface. There are two types of interfaces: Credit 1. Analogue to Digital (A/D) SensorA/D converter Computer Analogue signal Digital signal 2. Digital to Analogue (D/A) ComputerD/A converter Machine Digital signal Analogue signal

25. Slide 25 Standard Grade Computing Credit Types of Converter Transducer A transducer is a device which changes an external physical input (temperature, pressure or light) into a digital signal. Digitiser A digitiser converts a visual image from a video or TV camera into digital form that the computer can process.

26. Slide 26 Standard Grade Computing Credit A/D and D/A Converters The A/D and D/A converters are commonly stored on a ROM chip. The converters are in constant use in an automated system and storing them permanently in ROM avoids the need for constant loading and storing operations between backing storage and RAM. F/G/C Real Time Processing As the signal from the sensor is converted into digital data it is fed into the processor which then checks the data immediately and responds to it..

27. Slide 27 Standard Grade Computing Simulation A simulation is the imitation of a real - life system by a computer. Example: weather forecasting, where simulation can be used to predict likely developments in the weather pattern. Advantages: Mimic real - life situations for a fraction of the cost. Allow people to practice dangerous manoeuvres without any damage to them, others or machinery. Eg. training air plane pilots and nuclear power plant workers.

28. Slide 28 Standard Grade Computing CAD / CAM Computer Aided Design (CAD) This is a computer system used for commercial design work which consists of: a powerful computer, large high resolution colour monitor and a high quality colour plotter. Designers can create objects, plans or designs in 2 or 3 dimensions and store them on backing store. They can then be easily edited, rotated, viewed from different angles before being resaved or printed out.

29. Slide 29 Standard Grade Computing Computer Aided Manufacture (CAM) This is the use of computer controlled machines to produce objects. The machines can be either a range of robots or Computer Numeric Controlled (CNC) machines used for cutting shapes from metal. Once instructions are fed to them they will accurately cut the required shape eg car body parts

30. Slide 30 Standard Grade Computing Implications For Automation 1. Social Redundancies - computers are cheaper and quicker. Retraining - new jobs: maintenance, installation, updating hardware & software, managerial, supervisory etc. Improved life style - more leisure time - no more boring, repetitive and dangerous jobs. Health issues through prolonged use of computer: repetitive strain injury, eye strain etc..

31. Slide 31 Standard Grade Computing 2. Technical (i) Safety Moving parts of machinery must be covered. Area of movement of robot arm must be clearly marked with barrier. Path for robot vehicle must be marked with separate path for humans. Robot vehicles are fitted with collision detectors, lights and siren. (ii) Quality control Using automated systems the quality of a product can be kept consistent.

32. Slide 32 Standard Grade Computing Credit (iii) Systems Analyst The tasks performed by a systems analyst when changing to an automated workplace include: Is the workplace suitable for automation? Organise the layout of the workplace. Consider safety of people and robots in the design. Recommend hardware, including robots. Recommend software. Monitor, evaluate and improve process.

33. Slide 33 Standard Grade Computing (iv) Physical layout To design the physical layout of the factory the following details must be looked at: positioning of the robot arm paths for the mobile robots electrical or data communication wiring for the robot arms necessary safety procedures connected with the new system.

34. Slide 34 Standard Grade Computing 3. Economic (i) Cost Initial cost: cost of installing an automated system. Replacement cost: update hardware & software. Running cost: maintenance, consumables, power. Credit (ii)Manual system Labour Intensive - low level of equipment and lots of staff. Wage rises, holidays, sick, strikes... (iii)Automated system Capital Intensive - high level of equipment and few staff. Substantial initial investment.

35. Slide 35 Standard Grade Computing (iv)Production increases due to: increased speed of manufacture, accuracy and 24 hour operation. decreased costs in terms of wages and waste. high quality of goods produced. This leads to savings in the long term.