Standard Grade Standard Grade ComputingComputing

Automated SystemsAutomated Systems

What is an Automated SystemWhat is an Automated System

• The human provides the input.• The machine or computer processes the

data.• The machine or computer provides the

output.

Why use Automated Systems?Why use Automated Systems?• Faster than a human.• They do boring and repetitious jobs• They can be used in dangerous situations.• They are more efficient.• They can be programmed to do different

tasks - very flexible.• They are more accurate - don’t make

mistakes.

Open Loop ControlOpen Loop Control

Control computer

Control Information

Closed Loop ControlClosed Loop Control

Control computer

Traffic Sensor

Feedback from sensor

Control Information

What does a robot look like?What does a robot look like?

Stationary RobotsStationary Robots• Stay in one place all the time• e.g. used on factory assembly lines• Control programs are stored on disc or tape• Can be reprogrammed to do a different task

Anatomy of a Robot ArmAnatomy of a Robot Arm

• Some robots have parts that resemble human limbs

• A jointed robot arm has a– waist– shoulder– elbow– wrist– hand (specialised to suit the robot’s task)

Waist

Shoulder

Elbow

Wrist

Degrees of FreedomDegrees of Freedom

• Each moveable part of the arm is powered by an actuator.

• The number of degrees of freedom is the number of ways the arm can move.

• To work in three dimensions the arm must have at least three degrees of freedom.

• The human arm has eight degrees of freedom.

End EffectorsEnd Effectors• The ‘hand’ of the robot arm is specialised

to the task the robot is programmed to do.• The ‘hand’ could be a

– gripper– paint spray gun– welding electrode– suction cap– paint stripper– magnet

SensorsSensors• A sensor detects something e.g. heat, and

provides this input to the controlling computer.• Closed loop systems need sensors to

feedback information to the computer.• A thermostat controlling a heater is an example

of a closed loop.• A traffic sensor e.g. a loop of wire under the road

surface, sends information to the control computer.

Types of SensorsTypes of Sensors

• There are sensors to detect

– heat

– light

– collisions

– proximity

– magnetic fields

– pressure

Mobile RobotsMobile Robots

• Robots which move are called mobile robots.

CMU's Dante robot "walks" into volcanos. In 1994, NASA, Carnegie Mellon University and the Alaskan Volcano Observatory (AVO) used satellite and Internet connections to maneuver Dante into the active crater of Mt. Spur, an Alaskan volcano 90 miles west of Anchorage.

Mobile RobotsMobile Robots• Nomad is CMU's latest creation, a

four wheeled robot designed to traverse the solar system. The Nomad Robot has been looking for asteroids in Antartic.

• Carnegie Mellon built Nomad to explore the Antarctic in search of new meteorite samples in January 2000. Nomad spent nearly two weeks in the Arctic frost, examining over 100 indigenous rocks and ultimately classifying seven as bona-fide meteorites.

• "This is really the first time that a robot used its own intelligence to make a scientific conclusion about

something that it found."

Mobile RobotsMobile Robots• LePOT is a giant autonomous

mobile huge flower pot (on top of the Lakeside Technical College of Neuchatel (CPLN). Conceived by a group of local artists, the "moving flowerpot" concept was chosen as winner of a contest held to "beautify" the roof of the central building of CPLN.

• LePOT is 2 meters in diameter and 3 meters high, with a 23m carbon-fibre mast designed to sway aesthetically in the breeze.

Mobile RobotsMobile Robots• Problem: Stripping Paint from Very

Large Ship Hulls Ship owners now pay $400K - $800K to strip over 6 acres of painted surface with 150 sandblasting workers. They take 2 - 3 days, need a forest of scaffolding, damage the ship's surface, produce clouds of sand and 40 pounds of toxic sludge per square foot stripped, and halt other dry dock work by posing a health hazard. World market: over $100,000,000 per year. Major cost: shipping time lost in dry dock.

• Solution: M2000 Paint Stripping Robot

Automated Guided VehiclesAutomated Guided Vehicles

Remote-operated VehiclesRemote-operated Vehicles

Underwater ROV’s

Analogue SignalsAnalogue Signals

• Most electrical signals are analogue signals.

• Analogue signals vary continuously between two points.

Digital SignalsDigital Signals

• Computers can only work with digital signals.

• Digital signals have only two values - on or off.

Signal ConvertersSignal Converters

• A computer is connected to a device by an interface.

• The interface must be able to convert the computer’s digital signals to analogue signals if required.

• This is done by a digital to analogue converter.

• Signals can be changed in the other direction by an analogue to digital converter.

• A transducer is a device which changes a physical input e.g. heat, pressure or light into an analogue signal.

Control LanguagesControl Languages• Computer programs are always written in a

programming language.• You have learned to program in Visual

Basic.• Most robots are programmed to move using a

special control language.• They use meaningful commands like

forward, right, left, wait, grasp, up and down which relate to the robot world.

Teaching RobotsTeaching Robots• Programming by Example (lead-through programming)

– a human guides the robot– the positional sensors in the robot tell the computer

about the movement of each joint– the robot’s actuators (motors) repeat the stored

sequence of movements.• Programming Robots

– a programmer works out the whole sequence of movements and describes them in a high level language

– writing a new program will enable the robot to do a different task.

Social ImplicationsSocial Implications• Disadvantages

– workers will lose their jobs.– health risks associated with using a computer for

long periods of time.• Advantages

– workers can be retrained to do more interesting and skilled jobs.

– fewer people work in dangerous factory conditions.– workers who did boring jobs will have more leisure

time.– jobs will increase in the computing and leisure

industries.

Technical ImplicationsTechnical Implications• Safety

– moving parts of machine must be covered.– robot vehicles have sensors to detect if anything is in

the way– they can be programmed to move slowly so that

people can get out of their way– people are kept out of some areas of the factory– robot arms etc. should only operate when an item is in

position• Quality Control

Economic ImplicationsEconomic Implications• Automated Systems are Capital Intensive

– very expensive to install– but don’t demand wage rises– don’t require lunch breaks– don’t require canteens and toilet facilities– money will be saved in the long term

• Factories used to all be Labour Intensive– large number of workers required

• Increased Productivity– more goods manufactured in the same time for the

same cost

Robots in the FutureRobots in the Future

• Collecting the rubbish

• Hoovering the house