ACKNOWLEDGMENT

Though perseverance and enthusiasm combined with effort in the

right direction can bring forth the thing called success. But the realization

of the harsh reality that the path towards success is full of myriads,

temptations, impediments and pitfalls often proves to be disheartening in

such situation, it is the able guidance of knowledgeable person that steers

one through difficulties and help me achieve success.

I am highly obliged to express my deep sense of gratitude and

grateful thanks to my erudite guide Prof. H.S.DESHMUKH and Head of

Department of Mechanical Engineering, Dr. P.A. POTDUKHE for his

valuable guidance and support which led to the successful and timely

completion of my project.

I am secondly very thankful to year in charge

Prof. A.V KARMANKAR, for his valuable suggestions & guidance.

Last but not the least; I thank all those who directly or indirectly

helpful during my seminar preparation.

ANKIT PRASAD

V SEMESTER

DEPT OF MECHANICAL ENGG

R.C.E.R.T, CHANDRAPUR

III

CONTENTS

CHAPTERS PAGE

1. INTRODUCTION 1

1.1 Mechatronics 1

1.2 Description 1

1.3 Application 2

2. SERVOMECHANISM 3

2.1 Introduction 3

3. CONTROL SYSTEM 6

3.1 Introduction 6

3.2 Logic control

6 3.3 On-off control

7 3.4 Linear control

7 3.5 Proportional control

8

4. SENSING 9

4.1 Introduction 9

4.2 Thermal 10

4.3 Electromagnetic 10

4.4 Mechanical 10

4.5 Chemical 11

4.6 Optical radiation 11

4.7 Biological sensors 11

5. AUTOMATION 12

5.1 Introduction 12

5.2 Social impact 13

5.3 Current emphases 15

5.4 Automation tools 15

6. ROBOTICS 16

6.1 Introduction 16

6.2 Etymology 17

6.3 Components of robots 17

6.3.1 Actuation 17

6.3.2 Manipulation 19

IV

6.4 Locomotion 20

6.4.1 Rolling Robots 20

6.4.2 Walking Robots 21

6.4.3 Other methods of locomotion 22

6.5 Human interaction 24

7. APPLICATION OF ROBOTICS IN NUCLEAR INDUSTRIES 26

7.1 Walking and Climbing Service Robots for Safety Inspection

of Nuclear Reactor Pressure Vessels 26

7.1.1 Abstract 26

7.1.2Introduction 26

7.2 Nero series of climbing robots 27

7.2.1 Design Constraints 27

7.2.2 Mechanical System 28

7.2.3 Operational Experience 30

7.3 Sadie climbing robot 32

7.3.1 Grinding Application 33

7.3.2 Non Destructive Testing Application 34

7.4 Robots cleaning hazardous nuclear waste 34

7.4.1 WALL*E Robots 34

7.4.2 Fold track 35

7.4.3 Salt Mantis 36

7.4.4 Possum 36

7.5 Conclusion 37

LIST OF FIGURES

Fig 1.1 Aerial Venn diagram describes the various fields that make up Mechatronics 1

Fig 2.1 Small R/C servo mechanism 4

Fig 5.1 KUKA Industrial robots engaged in vehicle underbody assembly 13

Fig 6.1 The Shadow robot hand system holding a light bulb. 16

Fig 6.2 A robot leg, powered by Air Muscles. 18

Fig 6.3 Segway in the Robot museum in Nagoya. 20

Fig6.4 iCub robot, designed by the RobotCub Consortium. 21

Fig6.5 RQ-4 Global Hawk Unmanned Aerial Vehicle. 23

Fig 6.6 Two robot snakes. 23

Fig 6.7 Kismet (robot) can produce a range of Facial expressions. 24

V

Fig 7.1 NERO Robot and Its Control Console. 28

Fig7.2 NERO III. 29

Fig7.3 Reactor Pressure Vessel. 30

Fig7.4 RPV Cooling Hood. 31

Fig7.5 SADIE Robot and Its Tool Packages. 32

Fig7.6 Sizewell A Air Cooling Duct. 33

Fig7.7 Real-Life WALL*E Robots Cleaning Up After Nuke Waste. 35

Fig 7.8 FOLDTRACK. 35

Fig 7.9 Salt Mantis. 36

Fig 7.10 Possum. 36

VI

CHAPTER 1

INTRODUCTION

1.1 Mechatronics

Mechatronics ( or Mechanical and Electronics Engineering) is the combination of mechanical engineering, computer engineering and software engineering. The purpose of this interdisciplinary engineering field is the study of automata from an engineering perspective and serves the purposes of controlling advanced hybrid system. The word itself is a portmanteau of 'Mechanics' and 'Electronics'.

1.2 Description

Fig 1.1 Aerial Venn diagram describes the various fields that make up Mechatronics

Mechatronics is centred on mechanics, electronics, control engineering,

computing, molecular engineering ( from nanochemistry and biology) which,

combined, make possible the generation of simpler, more economical, reliable

and versatile systems. The portmanteau "Mechatronics" was first coined by

Mr. Tetsuro Mori, a senior engineer of the Japanese company Yaskawa, in 1969.

Mechatronics may alternatively be referred to as "electromechanical system" or

less often as "control and automation engineering".

2

Engineering cybernetics deals with the question of control engineering of

mechatronic systems. It is used to control or regulate such a system ( see control

theory). Through collaboration the mechatronic modules perform the production

goals and inherit flexible and agile manufacturing properties in the production

scheme. Modern production equipment consists of mechatronic modules that are

integrated according to a control architecture. The most known architectures

involve hierarchy, polyarchy hetaerachy ( often misspelled as heterarchy) and

hybrid. The methods for achieving a technical effect are described by control,

algorithm which may or may not utilize formal method in their design. Hybrid-

systems important to Mechatronics include production system, synergy drives,

planetary exploration rovers, automotive subsystems such as anti lock braking

system, spin-assist and every day equipment such as autofocus cameras, video,

hard disks, CD-players, washing machines.

A typical mechatronic engineering degree would involve classes in engineering

mechanics , mathematics, machine component design, mechanical design,

thermodynamics, circuits and systems, electronics and communications, control

theory, programming , digital signal processing, power engineering , robotics and

usually a final year thesis.

1.3 Application

Servo-mechanics

Sensing

Control System

Automation, and in the area of Robotics.

CHAPTER-2

SERVOMECHANISM

2.1 INTRODUCTION

A servomechanism, or servo is an automatic

device which uses error-sensing feedback to correct the performance of a

mechanism. The term correctly applies only to systems where the feedback or

error-correction signals help control mechanical position or other parameters. For

example an automotive power window control is not a servomechanism, as there

is no automatic feedback which controls position—the operator does this by

observation. By contrast the car's cruise control uses closed loop feedback,

which classifies it as a servomechanism.

Servomechanisms may or may not use a servomotor. For example a household

furnace controlled by thermostat is a servomechanism, yet there is no closed-

loop control of a servomotor.

A common type of servo provides position control. Servos are commonly

electrical or partially electronic in nature, using an electric motor as the primary

means of creating mechanical force. Other types of servos use hydraulics,

pneumatics, or magnetic principles. Usually , servos operate on the principle of

negative feedback, where the control input is compared to the actual position of

the mechanical system as measured by some sort of transducer at the output.

Any difference between the actual and wanted values ( an "error signal") is

amplified and used to drive the system i the direction necessary to reduce or

eliminate the error. An entire science known as control theory has been

developed on this type of system.

Servomechanisms were first used in military fire-control and marine navigation

equipment. Today servomechanisms are used in automatic machine tools,

satellite-tracking antennas, automatic navigation systems on boats and planes,

and antiaircraft-gun control systems. Other examples are fly-by-wire systems in

aircraft which use servos to actuate the aircraft's control surfaces, and radio-

controlled models which use RC servos for the same purpose. Many autofocus

cameras also use a servomechanism to accurately move the lens, and thus

adjust the focus. A modern hard disk drive has a magnetic servo system with

sub-micron positioning accuracy.

4

Another device commonly referred to as a servo is used in automobiles to

amplify the steering or braking force applied by the driver. In this form this device

is not a true servo, but rather a mechanical amplifier.

In industrial machines, servos are used to perform complex motion.

RC servos

Fig 2.1 Small R/C servo

mechanism

1. electric motor

2. position feedback

potentiometer

3. reduction gear

4. actuator arm

RC servos are hobbyist remote control devices servos typically employed in

radio-controlled models, where they are used to provide actuation for various

mechanical systems such as the steering of a car, the flaps on a plane, or the

rudder of a boat.

5

RC servos are composed of a DC motor mechanically linked to a potentiometer.

Pulse-width modulation ( PWM ) signals sent to the servo are translated into

position commands by electronics inside the servo. When the servo is

commanded to rotate, the DC motor is powered until the potentiometer

reaches the value corresponding to the commanded position.

Due to their affordability, reliability, and simplicity of control by microprocessors,

RC servos are often used in small-scale robotics applications.

The servo is controlled by three wires: ground (usually black/orange), power (red)

and control (brown/other colour). This wiring sequence is not true for all servos,

for example the S03NXF Std. Servo is wired as brown(negative), red (positive)

and orange (signal). The servo will move based on the pulses sent over the

control wire, which set the angle of the actuator arm. The servo expects a pulse

every 20 ms in order to gain correct information about the angle. The width of the

servo pulse dictates the range of the servo's angular motion.

A servo pulse of 1.5 ms width will set the servo to its "neutral" position, or 90°.

For example a servo pulse of 1.25 ms could set the servo to 0° and a pulse of

1.75 ms could set the servo to 180°. The physical limits and timings of the servo

hardware varies between brands and models, but a general servo's angular

motion will travel somewhere in the range of 180° - 210° and the neutral position

is almost always at 1.5 ms.

Servo motors are often powered from nickel-cadmium battery packs common to

most RC devices. Voltage ratings vary from product to product, but most servos

are operated at 4.8 V or 6 V DC from a 4 or 5 cell battery.

CHAPTER 3

CONTROL SYSTEM

3.1 INTRODUCTION

A control system is a device or set of devices to manage, command,

direct or regulate the behavior of other devices or systems.

There are two common classes of control systems, with many variations and

combinations: logic or sequential controls,and feedback or linear controls. There

is also fuzzy logic, which attempts to combine some of the design simplicity of

logic with the utility of linear control. Some devices or systems are inherently not

controllable.

The term "control system" may be applied to the essentially manual controls that

allow an operator to, for example, close and open a hydraulic press, where the

logic requires that it cannot be moved unless safety guards are in place.

An automatic sequential control system may trigger a series of mechanical

actuators in the correct sequence to perform a task. For example various electric

and pneumatic transducers may fold and glue a cardboard box, fill it with product

and then seal it in an automatic packaging machine.

In the case of linear feedback systems, a control loop, including sensors, control

algorithms and actuators, is arranged in such a fashion as to try to regulate a

variable at a setpoint or reference value. An example of this may increase the

fuel supply to a furnace when a measured temperature drops. PID controllers are

common and effective in cases such as this. Control systems that include some

sensing of the results they are trying to achieve are making use of feedback and

so can, to some extent, adapt to varying circumstances. Open-loop control

systems do not directly make use of feedback, but run only in pre-arranged ways.

3.2 Logic control

Pure logic control systems were historically implemented by electricians with

networks of relays, and designed with a notation called ladder logic. Today, most

such systems are constructed with programmable logic devices.

7

Logic controllers may respond to switches, light sensors, pressure

switches etc and cause the machinery to perform some operation. Logic systems

are used to sequence mechanical operations in many applications. Examples

include elevators, washing machines and other systems with interrelated stop-go

operations.

Logic systems are quite easy to design, and can handle very complex

operations. Some aspects of logic system design make use of Boolean logic.

3.3 On-off control

For example, a thermostat is a simple negative-feedback control: when the

temperature ( the "measured variable" or MV ) goes below a set point (SP), the

heater is switched on. Another example could be a pressure-switch on an air

compressor: when the pressure (MV) drops below the threshold (SP), the pump

is powered. Refrigerators and vacuum pumps contain similar mechanisms

operating in reverse, but still providing negative feedback to correct errors.

Simple on-off feedback control systems like these are

cheap and effective. In some cases, like the simple compressor example, they

may represent a good design choice.

In most applications of on-off feedback control, some consideration needs

to be given to other costs, such as wear and tear of control valves and maybe

other start-up costs when power is reapplied each time the MV drops. Therefore,

practical on-off control systems are designed to include hysteresis, usually in the

form of a deadband, a region around the setpoint value in which no control action

occurs. The width of deadband may be adjustable or programmable.

3.4 Linear control

Linear control systems use linear negative feedback to produce a control

signal mathematically based on other variables, with a view to maintaining the

controlled process within an acceptable operating range.

The output from a linear control system into the controlled process may be in the

form of a directly variable signal, such as a valve that may be 0 or 100% open or

anywhere in between. Sometimes this is not feasible and so, after calculating the

8

current required corrective signal, a linear control system may repeatedly switch

an actuator, such as a pump, motor or heater, fully on and then fully off again,

regulating the duty cycle using pulse-width modulation.

3.5 Proportional control

When controlling the temperature of an industrial furnace, it is usually

better to control the opening of the fuel valve in proportion to the current needs of

the furnace. This helps avoid thermal shocks and applies heat more effectively.

Proportional negative-feedback systems are based on the difference between the

required set point (SP) and measured value (MV) of the controlled variable. This

difference is called the error. Power is applied in direct proportion to the current

measured error, in the correct sense so as to tend to reduce the error (and so

avoid positive feedback). The amount of corrective action that is applied for a

given error is set by the gain or sensitivity of the control system.

At low gains, only a small corrective action is applied when errors are detected:

the system may be safe and stable, but may be sluggish in response to changing

conditions; errors will remain uncorrected for relatively long periods of time: it is

over-damped. If the proportional gain is increased, such systems become more

responsive and errors are dealt with more quickly. There is an optimal value for

the gain setting when the overall system is said to be critically damped. Increase

in loop gain beyond this point will lead to oscillations in the MV; such a system is

under-damped.

CHAPTER 4

SENSING

4.1 INTRODUCTION

A sensor is a device that measures a physical quantity and converts it into a

signal which can be read by an observer or by an instrument. For example, a

mercury thermometer converts the measured temperature into expansion and

contraction of a liquid which can be read on a calibrated glass tube. A

thermocouple converts temperature to an output voltage which can be read by

a voltmeter. For accuracy, all sensors need to be calibrated against known

standards.

Sensors are used in everyday objects such as touch-sensitive elevator

buttons and lamps which dim or brighten by touching the base. There are also

innumerable applications for sensors of which most people are never aware.

Applications include cars, machines, aerospace, medicine, manufacturing

and robotics.

A sensor's sensitivity indicates how much the sensor's output changes

when the measured quantity changes. For instance , if the mercury in a

thermometer moves 1 cm when the temperature changes by 1 °C, the

sensitivity is 1 cm/°C. Sensors that measure very small changes must have

very high sensitivities.

Technological progress allows more and more sensors to be manufactured on a

microscopic scale as microsensors using MEMS technology. In most cases, a

microsensor reaches a significantly higher speed and sensitivity compared with

macroscopic approaches.

Because sensors are a type of transducer, they change one form of

energy into another. For this reason, sensors can be classified according to

the type of energy transfer that they detect.

10

4.2 Thermal

Temperature sensors: thermometers, thermocouples, temperature sensitive

resistors (thermistors and resistance temperature detectors), bi-metal

thermometers and thermostats

Heat sensors: bolometer, calorimeter, heat flux sensor

4.3 Electromagnetic

electrical resistance sensors: ohmmeter, multimeter

electrical current sensors: galvanometer, ammeter

electrical voltage sensors: leaf electroscope, voltmeter

electrical power sensors: watt-hour meters

magnetism sensors: magnetic compass, fluxgate compass, magnetometer,

Hall effect device

metal detectors

RADAR

4.4 Mechanical

pressure sensors: altimeter, barometer, barograph, pressure gauge, air speed

indicator, rate-of-climb indicator, variometer

gas and liquid flow sensors: flow sensor, anemometer, flow meter, gas meter,

water meter, mass flow sensor

gas and liquid viscosity and density: viscometer, hydrometer, oscillating U-

tube

mechanical sensors: acceleration sensor, position sensor, selsyn, switch,

strain gauge

humidity sensors: hygrometer

11

4.5 Chemical

Chemical proportion sensors: oxygen sensors, ion-selective electrodes, pH

glass electrodes, redox electrodes, and carbon monoxide detectors.

Odour sensors: Tin-oxide gas sensors, and Quartz Microbalance sensors.

4.6 Optical radiation

Light time-of-flight. Used in modern surveying equipment, a short pulse of

light is emitted and returned by a retroreflector. The return time of the pulse is

proportional to the distance and is related to atmospheric density in a

predictable way - see LIDAR.

Light sensors, or photodetectors, including semiconductor devices such as

photocells, photodiodes, phototransistors, CCDs, and Image sensors;

vacuum tube devices like photo-electric tubes, photomultiplier tubes; and

mechanical instruments such as the Nichols radiometer.

Infra-red sensor, especially used as occupancy sensor for lighting and

environmental controls.

4.7 Biological sensors

All living organisms contain biological sensors with functions similar to those

of the mechanical devices described. Most of these are specialized cells that

are sensitive to:

light, motion, temperature, magnetic fields, gravity, humidity, vibration,

pressure, electrical fields, sound, and other physical aspects of the external

environment;

physical aspects of the internal environment, such as stretch, motion of the

organism, and position of appendages (proprioception);

an enormous array of environmental molecules, including toxins, nutrients,

and pheromones;

estimation of biomolecules interaction and some kinetics parameters;

CHAPTER 5

AUTOMATION

5.1 INTRODUCTION

Automation (ancient Greek: = self dictated), roboticization or industrial

automation or numerical control is the use of control systems such as computers

to control industrial machinery and processes, reducing the need for human

intervention. In the scope of industrialization, automation is a step beyond

mechanization. Whereas mechanization provided human operators with

machinery to assist them with the physical requirements of work, automation

greatly reduces the need for human sensory and mental requirements as well.

Processes and systems can also be automated.

Automation plays an increasingly important role in the global economy

and in daily experience. Engineers strive to combine automated devices with

mathematical and organizational tools to create complex systems for a rapidly

expanding range of applications and human activities.

Many roles for humans in industrial processes presently lie beyond

the scope of automation. Human-level pattern recognition, language recognition,

and language production ability are well beyond the capabilities of modern

mechanical and computer systems. Tasks requiring subjective assessment or

synthesis of complex sensory data, such as scents and sounds, as well as high-

level tasks such as strategic planning, currently require human expertise. In

many cases, the use of humans is more cost-effective than mechanical

approaches even where automation of industrial tasks is possible.

Specialised hardened computers, referred to as

programmable logic controllers (PLCs), are frequently used to synchronize the

flow of inputs from ( physical ) sensors and events with the flow of outputs to

actuators and events. This leads to precisely controlled actions that permit a tight

control of almost any industrial process.

13

Human-machine interfaces (HMI) or computer human interfaces

(CHI), formerly known as man-machine interfaces, are usually employed to

communicate with PLCs and other computers, such as entering and monitoring

temperatures or pressures for further automated control or emergency response.

Service personnel who monitor and control these interfaces are often referred to

as stationary engineers.

Fig 5.1 KUKA Industrial robots engaged in vehicle underbody assembly

5.2 Social impact

Automation has had a notable impact in a wide range of highly

visible industries beyond manufacturing. Once-ubiquitous telephone operators

have been replaced largely by automated telephone switchboards and answering

machines. Medical processes such as primary screening in electrocardiography

or radiography and laboratory analysis of human genes, sera, cells, and tissues

are carried out at much greater speed and accuracy by automated systems.

Automated teller machines have reduced the need for bank visits to obtain cash

and carry out transactions.

14

In general, automation has been responsible for the shift in the world economy

from agrarian to industrial in the 19th century and from industrial to services in

the 20th century.

The widespread impact of industrial automation raises social issues,

among them its impact on employment. Historical concerns about the effects of

automation date back to the beginning of the industrial revolution, when a social

movement of English textile machine operators in the early 1800s known as the

Luddites protested against Jacquard's automated weaving looms— often

by destroying such textile machines— that they felt threatened their jobs. One

author made the following case. When automation was first introduced, it caused

widespread fear. It was thought that the displacement of human operators by

computerized systems would lead to severe unemployment.

Critics of automation contend that increased industrial automation

causes increased unemployment; this was a pressing concern during the 1980s.

One argument claims that this has happened invisibly in recent years, as the fact

that many manufacturing jobs left the United States during the early 1990s was

offset by one-time massive increase in IT jobs at the same time. Some authors

argue that the opposite has often been true, and that automation has led to

higher employment. Under this point of view, the freeing up of the labour force

has allowed more people to enter higher skilled managerial as well as

specialised consultant/contractor jobs (like cryptographers), which are typically

higher paying. One odd side effect of this shift is that "unskilled labour" is in

higher demand in many first-world nations, because fewer people are available to

fill such jobs.

At first glance, automation might appear to devalue

labor through its replacement with less-expensive machines; however, the overall

effect of this on the workforce as a whole remains unclear. Today automation of

the workforce is quite advanced, and continues to advance increasingly more

rapidly throughout the world and is encroaching on ever more skilled jobs, yet

during the same period the general well-being and quality of life of most people in

the world ( where political factors have not muddied the picture ) have improved

dramatically. What role automation has played in these changes has not been

well studied.

15

5.3 Current emphases

Currently, for manufacturing companies, the purpose of automation

has shifted from increasing productivity and reducing costs, to broader issues,

such as increasing quality and flexibility in the manufacturing process.

The old focus on using automation simply to increase productivity and reduce

costs was seen to be short-sighted, because it is also necessary to provide a

skilled workforce who can make repairs and manage the machinery. Moreover,

the initial costs of automation were high and often could not be recovered by the

time entirely new manufacturing processes replaced the old. ( Japan's "robot

junkyards" were once world famous in the manufacturing industry.)

Automation is now often applied

primarily to increase quality in the manufacturing process, where automation can

increase quality substantially. For example, automobile and truck pistons used to

be installed into engines manually. This is rapidly being transitioned to automated

machine installation, because the error rate for manual installment was around

1-1.5%, but has been reduced to 0.00001% with automation. Hazardous

operations, such as oil refining, the manufacturing of industrial chemicals, and all

forms of metal working, were always early contenders for automation.

5.4 Automation tools

Different types of automation tools exists:

ANN - Artificial neural network

DCS - Distributed Control System

HMI - Human Machine Interface

SCADA - Supervisory Control and Data Acquisition

PLC - Programable Logic Controller

CHAPTER 6

ROBOTICS

6.1 INTRODUCTION

Robotics is the science and technology of

robots, their design, manufacture, and application. Robotics requires a working

knowledge of electronics, mechanics and software, and is usually accompanied

by a large working knowledge of many subjects. A person working in the field is

a roboticist.

Fig 6.1 The Shadow robot hand system holding a lightbulb.

The structure of a robot is usually mostly mechanical and

can be called a kinematic chain (its functionality being similar to the skeleton of

the human body). The chain is formed of links (its bones), actuators (its muscles)

and joints which can allow one or more degrees of freedom. Most contemporary

robots use open serial chains in which each link connects the one before to the

one after it. These robots are called serial robots and often resemble the human

arm. Some robots, such as the Stewart platform, use closed parallel kinematic

chains. Other structures, such as those that mimic the mechanical structure of

humans, various animals and insects, are comparatively rare. However, the

17

development and use of such structures in robots is an active area of research

(e.g. biomechanics). Robots used as manipulators have an end effector mounted

on the last link. This end effector can be anything from a welding device to a

mechanical hand used to manipulate the environment. ISO 10248 defines a

robotic application on the industrial field.

6.2 ETYMOLOGY

According to the Oxford English Dictionary, the word robotics

was first used in print by Isaac Asimov, in his science fiction short story "Liar!",

published in May 1941 in Astounding Science Fiction. Robotics is based on the

word "robot" coined by science fiction author Karel Čapek in his 1920 theater

play R.U.R. ( Rossum's Universal Robots, in Czech "Rossumovi univerzální

roboti"). The word robot comes from the word robota meaning "self labor",

and, figuratively, "drudgery" or "hard work" in Czech (and many other Slavic

languages). Asimov was unaware that he was coining the term for a new field

– as the design of electrical devices is called electronics, so the design of robots

could be appropriately called robotics.[3] Before the coining of the term, however,

there was interest in ideas similar to robotics (namely automata and androids)

dating as far back as the 8th or 7th century BC. In the Iliad, the god Hephaestus

made talking handmaidens out of gold. Archytas of Tarentum is credited with

creating a mechanical Pigeon in 400 BC.Robots are used in industrial, military,

exploration, home making, and academic and research applications.

6.3 COMPONENTS OF ROBOTS

6.3.1 Actuation

The actuators are the 'muscles' of a robot; the parts which convert stored energy

into movement. By far the most popular actuators are electric motors, but there

are many others, some of which are powered by electricity, while others use

chemicals, or compressed air.

Motors: By far the vast majority of robots use electric motors, of which there

are several kinds. DC motors, which are familiar to many people, spin rapidly

18

when an electric current is passed through them. They will spin backwards if

the current is made to flow in the other direction.

Stepper motors: As the name suggests, stepper motors do not spin freely

like DC motors, they rotate in steps of a few degrees at a time, under

the command of a controller. This makes them easier to control, as the

controller knows exactly how far they have rotated, without having to use a

sensor.Therefore they are used on many robots and CNC machining centres.

Fig 6.2 A robot leg, powered by Air Muscles.

Piezo motors: A recent alternative to DC motors are piezo motors, also

known as ultrasonic motors. These work on a fundamentally different

principle, whereby tiny piezoceramic legs, vibrating many thousands of times

per second, walk the motor round in a circle or a straight line. The advantages

of these motors are incredible nanometre resolution, speed and available

force for their size. These motors are already available commercially, and

being used on some robots.

Air muscles: The air muscle is a simple yet powerful device for providing a

pulling force. When inflated with compressed air, it contracts by up to 40% of

its original length. The key to its behavior is the braiding visible around the

outside, which forces the muscle to be either long and thin, or short and fat.

Since it behaves in a very similar way to a biological muscle, it can be used to

construct robots with a similar muscle/skeleton system to an animal. For

example, the Shadow robot hand uses 40 air muscles to power its 24 joints.

Electroactive polymers: Electroactive polymers are a class of plastics which

change shape in response to electrical stimulation. They can be designed so

that they bend, stretch or contract, but so far there are no EAPs suitable for

19

commercial robots, as they tend to have low efficiency or are not robust.

Indeed, all of the entrants in a recent competition to build EAP powered arm

wrestling robots, were beaten by a 17 year old girl.

Elastic nanotubes: These are a promising, early-stage experimental

technology. The absence of defects in nanotubes enables these filaments

to deform elastically by several percent, with energy storage levels of perhaps

10J per cu cm for metal nanotubes. Human biceps could be replaced with an

8mm diameter wire of this material. Such compact "muscle" might allow future

robots to outrun and outjump humans.

6.3.2 Manipulation

Robots which must work in the real world require some

way to manipulate objects; pick up, modify, destroy or otherwise have an effect.

Thus the 'hands' of a robot are often referred to as end effectors, while the arm is

referred to as a manipulator. Most robot arms have replaceable effectors, each

allowing them to perform some small range of tasks. Some have a fixed

manipulator which cannot be replaced, while a few have one very general

purpose manipulator, for example a humanoid hand.

Grippers: A common effector is the gripper. In its simplest manifestation it

consists of just two fingers which can open and close to pick up and let go of

a range of small objects. See End effectors.

Vacuum Grippers: Pick and place robots for electronic components and for

large objects like car windscreens, will often use very simple vacuum

grippers. These are very simple astrictive devices, but can hold very large

loads provided the prehension surface is smooth enough to ensure suction.

General purpose effectors: Some advanced robots are beginning to use

fully humanoid hands, like the Shadow Hand and the Schunk hand. These

highly dexterous manipulators, with as many as 20 degrees of freedom and

hundreds of tactile sensors can be difficult to control. The computer must

consider a great deal of information, and decide on the best way to

manipulate an object from many possibilities.

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6.4 Locomotion

6.4.1 Rolling Robots

For simplicity, most mobile robots have four wheels. However, some researchers

have tried to create more complex wheeled robots, with only one or two wheels.

Two-wheeled balancing: While the Segway is not commonly thought

of as a robot, it can be thought of as a component of a robot. Several real

robots do use a similar dynamic balancing algorithm, and NASA's Robonaut

has been mounted on a Segway.

Fig 6.3 Segway in the Robot museum in Nagoya.

Ballbot: Carnegie Mellon University researchers have developed a new type

of mobile robot that balances on a ball instead of legs or wheels. "Ballbot" is a

self-contained, battery-operated, omnidirectional robot that balances

dynamically on a single urethane-coated metal sphere. It weighs 95 pounds

and is the approximate height and width of a person. Because of its long, thin

shape and ability to maneuver in tight spaces, it has the potential to function

better than current robots can in environments with people.

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6.4.2 Walking Robots

Walking is a difficult and dynamic problem to solve. Several

robots have been made which can walk reliably on two legs, however none have

yet been made which are as robust as a human. Typically, these robots can walk

well on flat floors, and can occasionally walk up stairs. None can walk over rocky,

uneven terrain. Some of the methods which have been tried are:

ZMP Technique: The Zero Moment Point (ZMP) is the algorithm used by

robots such as Honda's ASIMO. The robot's onboard computer tries to keep

the total inertial forces (the combination of earth's gravity and the acceleration

and deceleration of walking), exactly opposed by the floor reaction force (the

force of the floor pushing back on the robot's foot). In this way, the two forces

cancel out, leaving no moment (force causing the robot to rotate and fall

over). However, this is not exactly how a human walks, and the difference is

quite apparent to human observers, some of whom have pointed out that

ASIMO walks as if it needs the lavatory. ASIMO's walking algorithm is not

static, and some dynamic balancing is used (See below). However, it still

requires a smooth surface to walk on.

Fig6.4 iCub robot, designed by the RobotCub Consortium

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Hopping: Several robots, built in the 1980s by Marc Raibert at the MIT Leg

Laboratory, successfully demonstrated very dynamic walking. Initially, a robot

with only one leg, and a very small foot, could stay upright simply by hopping.

The movement is the same as that of a person on a pogo stick. As the robot

falls to one side, it would jump slightly in that direction, in order to catch itself.

Soon, the algorithm was generalised to two and four legs. A bipedal robot

was demonstrated running and even performing somersaults. A quadruped

was also demonstrated which could trot, run, pace and bound. For a full list of

these robots, see the MIT Leg Lab Robots page.

Dynamic Balancing: A more advanced way for a robot to walk is by using a

dynamic balancing algorithm, which is potentially more robust than the Zero

Moment Point technique, as it constantly monitors the robot's motion, and

places the feet in order to main stability. This technique was recently

demonstrated by Anybots' Dexter Robot, which is so stable, it can even jump.

Passive Dynamics: Perhaps the most promising approach utilises passive

dynamics where the momentum of swinging limbs is used for greater

efficiency. It has been shown that totally unpowered humanoid mechanisms

can walk down a gentle slope, using only gravity to propel themselves. Using

this technique, a robot need only supply a small amount of motor power to

walk along a flat surface or a little more to walk up a hill. This technique

promises to make walking robots at least ten times more efficient than ZMP

walkers, like ASIMO.

6.4.3 Other methods of locomotion

Flying: A modern passenger airliner is essentially a flying robot, with two

humans to attend it. The autopilot can control the plane for each stage of the

journey, including takeoff, normal flight and even landing. Other flying robots

are completely automated, and are known as Unmanned Aerial Vehicles

(UAVs). They can be smaller and lighter without a human pilot, and fly into

dangerous territory for military surveillance missions. Some can even fire on

targets under command. UAVs are also being developed which can fire on

targets automatically, without the need for a command from a human. Other

flying robots include cruise missiles, the Entomopter and the Epson micro

helicopter robot.

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Fig6.5 RQ-4 Global Hawk Unmanned Aerial Vehicle

Snaking: Several snake robots have been successfully developed. Mimicking

the way real snakes move, these robots can navigate very confined spaces,

meaning they may one day be used to search for people trapped in collapsed

buildings. The Japanese ACM-R5 snake robot can even navigate both on

land and in water

Fig 6.6 Two robot snakes. Left one has 32 motors, the right one 10.

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Skating: A small number of skating robots have been developed, one of

which is a multi-mode walking and skating device, Titan VIII. It has four legs,

with unpowered wheels, which can either step or roll. Another robot, Plen, can

use a miniature skateboard or rollerskates, and skate across a desktop.

Swimming: It is calculated that when swimming some fish can achieve a

propulsive efficiency greater than 90%. Furthermore, they can accelerate and

maneuver far better than any man-made boat or submarine, and produce less

noise and water disturbance. Therefore, many researchers studying

underwater robots would like to copy this type of locomotion. Notable

examples are the Essex University Computer Science Robotic Fish, and the

Robot Tuna built by the Institute of Field Robotics, to analyse and

mathematically model thunniform motion.

6.5 Human interaction

If robots are to work effectively in homes and other non-industrial environments, the way they are instructed to perform their jobs, and especially how they will be told to stop will be of critical importance. The people who interact with them may have little or no training in robotics, and so any interface will need to be extremely intuitive. Science fiction authors also typically assume that robots will eventually communicate with humans by talking, gestures and facial expressions, rather than a command-line interface. Although speech would be the most natural way for the human to communicate, it is quite unnatural for the robot. It will be quite a while before robots interact as naturally as the fictional C3P0.

Fig 6.7 Kismet (robot) can produce a range of Facial expressions

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Speech recognition: Interpreting the continuous flow of sounds coming from a human (speech recognition), in real time, is a difficult task for a computer, mostly because of the great variability of speech. The same word, spoken by the same person may sound different depending on local acoustics, volume, the previous word, whether or not the speaker has a cold, etc.. It becomes even harder when the speake has a different accent. Nevertheless, great strides have been made in the field since Davis, Biddulph, and Balashek designed the first "voice input system" which recognized "ten digits spoken by a single user with 100% accuracy" in 1952. Currently, the best systems can recognise continuous, natural speech, up to 160 words per minute, with an accuracy of 95%.

Gestures: One can imagine, in the future, explaining to a robot chef how to make a pastry, or asking directions from a robot police officer. On both of these occasions, making hand gestures would aid the verbal descriptions. In the first case, the robot would be recognising gestures made by the human, and perhaps repeating them for confirmation. In the second case, the robot police officer would gesture to indicate "down the road, then turn right". It is quite likely that gestures will make up a part of the interaction between humans and robots. A great many systems have been developed to recognise human hand gestures.

Facial expression: Facial expressions can provide rapid feedback on the progress of a dialog between two humans, and soon it may be able to do the same for humans and robots. A robot should know how to approach a human, judging by their facial expression and body language. Whether the person is happy, frightened or crazy-looking affects the type of interaction expected of the robot. Likewise, a robot like Kismet can produce a range of facial expressions, allowing it to have meaningful social exchanges with humans.

Personality: Many of the robots of science fiction have personality, and that is something which may or may not be desirable in the commercial robots of the future. Nevertheless, researchers are trying to create robots which appear to have a personality: i.e. they use sounds, facial expressions and body language to try to convey an internal state, which may be joy, sadness or fear. One commercial example is Pleo, a toy robot dinosaur, which can exhibit several apparent emotions.

CHAPTER 7

APPLICATION OF ROBOTICS IN

NUCLEAR INDUSTRIES

7.1 Walking and Climbing Service Robots for Safety Inspection of Nuclear Reactor Pressure Vessels

7.1.1 ABSTRACT: Nuclear reactor pressure vessels are often required regular

inspection and maintenance in order to ensure the safety of the reactors. Failing

to carry out proper maintenance could cause severe casualty. The usual way of

carrying out inspection in these hazardous environments is using long reach

fixed base manipulators. However, these manipulators suffer from low payload

capacity and relatively large end point deflections. Also, the installation and the

storage of these long manipulators could be costly. An alternative solution is to

use walking-climbing robots, which overcome the problems encountered by the

long reach manipulators. In this paper, two robots, NERO (Nuclear Electric Robot

Operator) and SADIE ( Sizewell A Duct Inspection Equipment) which have been

applied successfully to inspect two Magnox reactors in the UK are described.

The deployment and operational experience of these robots are also explained.

Finally the applications and the usefulness of these robots for improving safety

inspection of nuclear reactors in general are discussed in this paper.

7.1.2 INTRODUCTION

Inspection and maintenance is essential in the nuclear industry. Failure to carry

out proper maintenance could increase the chance of accidents which could

result in severe casualty not only inside the nuclear plant but also in the near-by

community. However, it is not easy to carry out such maintenance tasks since

the environments are usually highly radioactive and are unsafe for human

workers to work in such locations. The usual way of carrying out inspection and

maintenance tasks in these hazardous environments is using long reach fixed

base manipulators. However, these manipulators suffer from low payload

capacity and relatively large end point deflections. Also, the installation and the

storage of these long manipulators could be costly. An alternative solution is to

use walking-climbing robots, which overcome the problems encountered by the

long reach manipulators. Over the years, a number of climbing robots has been

27

Developed for various applications. However, most of these robots are only

engineering prototypes and have not been used for any extensive inspection and

maintenance operations . In this paper, we describe a number of teleoperated

walking-climbing robots developed by authors, which include NERO series and

SADIE series. These robots have been designed for remote inspection and

maintenance applications, especially for the nuclear industry. All of these robots

have been applied successfully in practical applications.

7.2 NERO SERIES OF CLIMBING ROBOTS

Magnox type Nuclear Reactors form the early generation of commercial nuclear

reactors in the U.K. In order to extend the life of an early-built reactor, a Non-

Destructive Test (NDT) programme was set up to inspect part of the Reactor

Pressure Vessel (RPV) at the Trawsfynydd nuclear power station. Since the

design of this reactor only provided limited access for engineering servicing, fixed

base manipulators with multiple linkages could not reach all the required areas of

the RPV. As a result, NEROs were designed to carry out various tasks of the

NDT programme. NERO (Nuclear Electric Robot Operator) was a pneumatically

driven nonarticulated legged vehicle. It used vacuum gripper feet to hold on the

RPV surfaces. It was originally designed to assist the installation of additional

thermocouples onto the RPV surface. Later designs, NERO II and NERO III,

were fitted with wire brush andmetal cutter respectively for surface preparation.

NERO had the ability to step over small obstacles and crawled under low

overhangs

7.2.1 Design Constraints

NERO were designed to work on the outside surface of an RPV. The RPV was

an 18.7m diameter welded steel sphere structure. The vehicle had to cope with

this curvature and with any local variations. A cooling hood was situated over the

top of the vessel to direct a flow of cooling air over the crown of vessel. The gap

between the cooling hood and the vessel was approximately 250mm. This gap

restricted the height of the mobile vehicle. There were a number of

thermocouples installed on the surface which were up to 25 mm high and which

the mobile vehicle was required to step over. Due to the prohibited access to the

RPV because of the radiation hazard, the vehicle had to be driven remotely by an

28

operator at the end of a 50m umbilical cable. Since the RPV surface was

potentially covered with contaminated substances, it was an important design

constraint that the feet did not collect loose material in order to allow the

operators service the vehicle. The surface preparation tools were heavy and

together with the weight of the umbilical power and communication cable, NERO

had to be powerful.

7.2.2 Mechanical System

All the NERO type of tele-operated vehicles shared the same

basic drive mechanism consisting of two rectangular structures - a Frame and a

Shuttle. The Frame was the outer moving structure and the Shuttle was the inner

moving structure. Each structure carried four specially designed vacuum gripper

feet which attached onto pneumatic extending 'leg' cylinders. This arrangement

allowed the vehicle to step over 25mm obstacles without the need of excessive

headroom. In order to ensure that the vehicle could operate on uneven and

rough surfaces, redundancy had been built into the system. The whole robot

could be held onto the surface with only two front feet or a diagonal pair gripping.

Compliance was obtained by adjustment of the leg cylinder pressures and was

also provided by ball joints between the 'leg' cylinders and the gripper feet.

Fig 7.1 NERO Robot and Its Control Console

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The translation movement of the structures were achieved by a double acting

pneumatic cylinder. The end of the cylinder rods were attached to Frame whilst

the cylinder body was attached to a metal plate on the Shuttle. This metal plate

was connected to the Shuttle rotary centre column. Rotary actuation was

achieved by a further double acting cylinder which was mounted on the Shuttle

plate and linked to the Shuttle rotary centre column. Both translation and rotation

pneumatic cylinders were controlled by solenoid valves. A Pulse Width

Modulation method was used to drive the cylinders in a force and position servo

control system. The choice of pneumatic actuation gives the vehicle the high

power to weight ratio and inherent compliance which had been found essential

for climbing vehicles.

Motion was achieved by sequences of stepping, sliding and rotating movements.

In order to move the vehicle, one structure would stand with its feet gripping on

the surface whilst the feet of the other structure would be lifted and free to move.

This allowed the structure with its feet lifted to rotate or translate. Movement in

the same direction was achieved by swapping the raised structure with the

gripping structure. An all eight feet gripping stage was implemented between

swapping gripping structure to ensure maximum safety while walking on the RPV

surface.

fig 7.2 NERO III

30

In order to avoid picking up contaminated substances from the surface, the

gripper foot developed its vacuum from a compress air ejector pump. By

reversing the flow, the air ejector cleaned the filter in the foot and at the same

time clears loose material on the surface prior to gripping. Safety was one of the

important issues in the design of NERO system. The pneumatic control valves

were arranged so that in the event of electrical power failure, the system would

failsafe by lowering the vehicle on to the surface so that it griped with all eight

feet in its lowest profile mode. The pneumatic supply system used two

compressors and an automatic selection valve to protect the NERO system from

pneumatic supply failure. Wherever possible a safety wire was taken up to avoid

damaging force in the event of a fall. Three NERO type vehicles were built.

NERO I carried a special tape feeder for installing additional thermocouples.

NERO II had a rotating wire brush for removing loose materials from the RPV

surface. NERO III (see Figure 4) had a 1.3HP rotary disc grinder fitted on a swing

arm and was mainly used for removing unwanted studs and weld splatter from

the surface.

7.2.3 Operational Experience

Due to the limited access to the RPV, all the mobile vehicles had to enter the

void containing the RPV from the 4 entrances at the base of the biological shield.

Fig 7.3 Reactor Pressure Vessel

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Fig7.4 RPV Cooling Hood

Vehicles had to be hoisted up around the equator of the RPV before it was

possible to place them onto the RPV surface. The 250 mm diameter Vessel

Viewing stand-pipe was found suitable for feeding a steel cable from the Charge

Face to hoist the vehicles. The umbilical cable of each vehicle was also fed

through the Vessel Viewing stand-pipe. This arrangement allowed the operator to

manoeuvre the position of the umbilical cable on the RPV surface and reduce the

weight of the cables that the vehicle had to carry. Because the convenience of

hoisting NERO from this position, the vehicle control stations were placed on the

Charge Face. Since the radiation level at the entrance of the void was high,

conveyor belts were set up at each entrance for transporting the vehicles into the

void. Several ground mobile vehicles were also used to assist vehicle launching.

Flat metal plates were installed on top of these ground mobile vehicles and the

wall climbing vehicle was placed on this plate during launching. The whole unit

was then placed onto the conveyor. Once the ground mobile vehicle was

transported inside the void by the conveyor, it carried the wall climbing vehicle to

a suitable location inside the void and the wall climbing vehicle was then hoisted

up onto RPV. Wires were attached at the rear side of the wall climbing

vehicle. These wires were also connected to ground mobile vehicles and were

used to manoeuvre the wall climbing vehicles onto the surface.

32

In-circuit television cameras and lights were placed inside the void to monitor all

the launching operations. Cameras could also be inserted through the Vessel

Viewing standpipe. However, all these cameras could only provide pictures

around the equator area. As soon as the wall climbing vehicle climbed above the

Vessel Viewing stand-pipe, it was solely dependent on its onboard cameras.

Once the vehicle had been launched onto the RPV surface, one operator was

required to drive the vehicle, one worker was needed to handle the umbilical

cable and one supervisor to oversee the operation. All the actions were

conducted with extreme care to ensure the safety of the operations.

7.3 SADIE CLIMBING ROBOT

The SADIE (Sizewell A Duct Inspection Equipment) robot was commissioned by

Magnox Electric plc to perform non-destructive testing of various welds on the

main reactor cooling gas ducts at Sizewell ‘A’ Power Station. It was determined

that a vehicle similar in size (640 mm x 400 mm x 180 mm) and concept to

NERO would be able to carry the necessary equipment for the range of tasks

required, including pre-inspection preparation and ultrasonic weld inspection. The

actual robot and its control console are shown in Figure 5 and 6 respectively. A

part of the requirement was that the robot would need to climb upside down at

the top of the duct to inspect some of the welds. It was therefore necessary to

develop a force controlled foot change over sequence.

Fig7.5 SADIE Robot and Its Tool Packages 33

The welds which required preparation and inspection were RC 24, RC 25,

RC 26, SC 12, M 1, L 1 and L 2.

Fig7.6 Sizewell A Air Cooling Duct

7.3.1 Grinding Application

During the initial design of the SADIE robot it was identified that some of the weld

which required inspection where obscured by ladder brackets welded on or

adjacent to them. A requirement of SADIE was to carry a specially designed

grinding package to remove the ladder bracket. It was important that the ladder

brackets were recovered from the duct and a grab mechanism was incorporated

on to the cutting tool.

The ladder bracket removal package (LBRP) was mounted on the front frame of

the vehicle and consisted of two main elements. An air powered disk grinder

mounted on a cross feed, and a pneumatically operated grab mechanism.

The grinding tool and cross feed was hinged about the axis of the cross feed. A

pivot allowed the cross feed to rotate on about axis perpendicular to the cross

feed axis. These degrees of freedom allowed the grinder to follow the curves in

the duct, providing compliance with the contours of the surface. This compliance

was stabilised by ball transferr units on either side of the grinder disk and a

34

Centrally positioned pneumatic cylinder applying a steady force ensuring the

transfer balls stayed on the surface.

The pneumatic cylinder also provided lift to allow the grinder to be raised off the

surface when manoeuvring in to position. The cross feed was driven by a force

controlled pneumatic cylinder.

The grab mechanism was positioned above the cross feed. The ladder bracket

was held in a U bracket with a spring return piston actuating a bolt through the

hole in the ladder bracket. The arm was actuated using additional pneumatic

cylinders to provide a lift/lower and extended/retract functions.

The mechanism used a camera for primary observation and micro-switches to

indicate the ends of the cross fed travel. The cross feed actuators utilised a

differential pressure sensor to provide force sensing.

To allow more than one ladder bracket to be removed per deployment a ladder

bracket box was designed. This box was mounted on the deployment scoop. Its

design incorporated a hinged lid which was kept shut with a spring. The lid traps

the ladder bracket within the box.

7.3.2 Non Destructive Testing Application

To inspect the welds Ultrasonic scanning was used.

An inspection tool was designed by Magnox Electric for SADIE which could carry

the Ultrasonic transducers. An array of sensors were used in what was known as

the probe pan. The probe pan was used a gimbal joint to ensure that is followed

the surface and was scanned across the weld by a servo controlled linear axis

mounted across the front of the vehicle. The probe pan contained a system for

squirting ultrasonic couplant around the transducers so that good quality signals

were produced. The ultrasonic couplant was a water based gel to avoid the need

for cleaning the gel after the inspection.

7.4 ROBOTS CLEANING NUCLEAR HAZARDOUS WASTE

7.4.1 WALL*E Robots

Robots are being used to clean humanity’s worst messes. At Hanford Nuclear

Reservation in Washington State, where plutonium for Cold War nukes was

made, robots are on the front line of the cleanup effort. The job is to empty about

150 basketball-court-sized tanks of nuclear and chemical waste before their

contents reach the Columbia River. Exposure to the material would kill a human

within moments. Sounds like a job for robots.

35

Fig 7.7 Real-Life WALL*E Robots Cleaning Up After Nuke Waste

Since there won’t be any attention from Pixar, we again salute the little guys

going a bit beyond the iRobot Looj in their daring damage control.

7.4.2 Fold track

Fig 7.8 FOLDTRACK

The only way in or out of most of the tanks is through foot-wide pipes in their

roofs, so engineers at Hanford use this robotic dozer, which opens into a string of

pieces that fit through the inlets. Once inside, Fold track reassembles like a toy

Transformer. The robot uses a 3000 psi water stream to blast at sludge from up

to 20 ft. away. A remote driver directs the robot as it uses a dozer blade to push

the waste toward a pump for transfer to safer, double-shelled tanks. Once its job

is done, the $500,000 robot is sealed, forever, in the empty tank.

36

7.4.3 Salt Mantis

Fig 7.9 Salt Mantis

This robot may not look like much but a glorified fire hose, but it’s hiding a

valuable secret. The Salt Mantis can shoot water at up to 35,000 psi to blast

tough toxic salts that build up inside nuclear waste tanks. The water jets from a

tiny orifice made of gems, including sapphires—the only material that can

(literally) stand up to the pressure. The robot’s crosslike body scissors together to

squeeze into the narrow opening of the sludge tanks. While inside it moves

around by remote control, since onboard electronics would fry from the exposure

to radiation.

7.4.4 Possum

Fig 7.10 Possum

It used to be that human cleaners had to just guess if the radioactive area they

were cleansing was, indeed, clean. Like a faithful retriever, the Possum rolls to

the far, dark reaches of waste tanks, scooping up samples with its bulldozer like

37

blade so engineers can tell exactly what, and how much, is left inside. The

Possum comes equipped with a camera so operators can locate target waste

and control the device.

7.5 CONCLUSION

Mechatronics is the vast field of mechanical engineering

which provide the idea, principles and design parameter for the mechatronics

application. After the revolution in the industrial sector the demand for machines

has been increased tremendously which lead to the development of the various

machines which working mechanism is mostly influenced by the electronics

and mechanical principles of working of machinery.

Mechatronics development provides support to various field of engineering and

non engineering field by its various sub fields like servomechanisms, sensing,

control system, automation etc.

Mechatronics is used in production of robots. All the features of robots are

influenced by the principles of electronics, mechanics , control and software.

Robots is widely used in many industries for better work, efficient production, and

is more reliable than human work force also it is more cost efficient.

Robots are mainly used in nuclear industries for various applications. In nuclear

industries various work can not be done by humans because of the radioactive

materials and radiations which damage human seriously and causes mutations

lethal disease . Also various repair and maintenance work is done by robots

where human invasion can not be possible.

In the last ,we have discussed about number of

climbing robots, which included NERO series and SADIE series. All these robots

used the same sliding frame walking mechanism. In order to allow these robots

to climb on different surfaces, vacuum gripping technology was used. For

handling uneven or rough surfaces, force control was implemented to control the

movements of the legs. All these robots have been applied successfully in real

applications and have confirmed the usefulness of these service robots for

remote inspection and maintenance applications. With the increasing demands in

health and safety, there is no doubt that this kind of service robots will become

essential in the near future.

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BIBLIOGRAPHY

1. MECHATRONICS, HMT Limited, TATA McGraw HILL, New Delhi, 1998.

2. PRODUCTION SYSTEMS AND COMPUTER INTEGRATED

MANUFACTURING, MIKELL P.GROOVER, EASTERN ECONOMY EDITION,

Prentice Hall, New Delhi, 2006.

3. Article, Walking and Climbing Service Robots for Safety Inspection of NuclearReactor Pressure Vessels, Department of Manufacturing Engineering and Engineering Management, City University of Hong Kong, Hong Kong

4. www.ocrobotics.com

5. www.mit.org

6. www.popularmechanics.com

7. www.howstuffworks.com

8. Wikipedia.