Robots

[mojam]

Ran out of floppy discs. Please don't delete this so i can open it at school.

 

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TABLE OF CONTENTS

 

TABLE OF CONTENTS I

TABLE OF ILLUSTRATIONS II

TABLE OF TABLES III

1 – INTRODUCTION 1

2 – BACKGROUND HISTORY 2

3 – BENEFITS OF ROBOTS 6

4 - USES OF ROBOTS 6

5 – INDUSTRIAL ROBOTS 11

6 – RADIO CONTROLLED TOYS 21

7 – ROBOTS IN THE FUTURE 30

8 – CONCLUSION 32

 

 

TABLE OF ILLUSTRATIONS

 

FIGURE 2-1: RUR 3

FIGURE 2-2: CLEPSYDRA 4

FIGURE 4-1:ROBOT WELDER 7

FIGURE 4-2: MARS EXPLORER 7

FIGURE 4-3: ROBOTIC SURGERY ROOM 8

FIGURE 4-4: ROBOTIC SURGERY END EFFECTOR 9

FIGURE 4-5: BOMB DISPOSAL ROBOT 10

FIGURE 4-6: LEGO MINDSTORMS 10

FIGURE 5-1: AUTOMOTIVE MANUFACTURING 11

FIGURE 5-2: ARTICULATED GEOMETRY 13

FIGURE 5-3: INDUSTRIAL ROBOTIC SYSTEM 13

FIGURE 5-4: ROBOTIC ARM 14

FIGURE 5-5: DEGREES OF FREEDOM 15

FIGURE 5-6: ELECTRIC DC MOTOR 17

FIGURE 5-7: RECTIFIER 18

FIGURE 5-8: COMPLETE AC TO DC CONVERSION CIRCUIT 18

FIGURE 5-9: STEPPER MOTOR 19

FIGURE 6-1: HELICOPTER 21

FIGURE 6-2: CONTROLLER 22

FIGURE 6-3: PULSE SEGMENT 24

FIGURE 6-4: INSIDE A RC TRUCK 25

FIGURE 6-5: PM 26

FIGURE 6-6: AM 26

FIGURE 6-7: FM 27

 

 

TABLE OF TABLES

 

 

TABLE 2-1: ROBOTIC TIMELINE 6

TABLE 5-1: COILS 20

TABLE 6-1: RC TOY MAIN PARTS 21

TABLE 6-2: COMMON FREQUENCY BANDS 28

TABLE 6-3: WIRELESS FREQUENCY BANDS 28

 

 

1 – Introduction

This technical report on robotics will touch on various subjects related to robotics. First a background history will be given on robotics. The background history will cover the very early robots, which by today’s definition wouldn’t be considered robots at all. However, these early machines can be considered to be the ‘ancestors’ so to say of robots as we know them today. In the last section of the background history section a brief history will be given on modern robotics. This includes when the first industrial robots were developed and used in assembling factories and also what companies were the major players in developing these robots.

 

After the background history, two sections of the report will be examined dealing with the benefits associated with robotics and also what different application robots are used for. Although, robots are used in unlimited different application only four of them will be presented in this report. They include industry, exploration, medicine, entertainment, police and military, and toys. Two of these topics will be discussed in detail later in the technical aspect of the report.

 

In the technical section of the report industrial robotics will first be discussed. In this section, topics dealing Electronics Engineering and also Mechanical Engineering will be discussed. In the section about the robotic arm the hydraulic, pneumatic, and electrical driving systems will be discussed in detail. Also a few schematic diagrams used in industrial plants will be presented, of which one is explained in detail.

 

Section six of the report covers the topic of radio controlled toys. Here the transmitter, controller will be explained in detail. Also, the three different communications principles involved with radio commutations will be discussed. Amplitude Modulation (AM), Frequency Modulation (FM), and Pulse Modulation (PM) are explained briefly with explanatory graphics. In the last section of the report the future of robotics will be discussed. Artificial Intelligence (AI) will be defined and where it’s going in the future will be discussed.

 

2 - Background History

The Idea of a Robot

The idea of a robot is not new. For thousands of years man has been imagining intelligent mechanized devices that perform human-like tasks. Throughout the years, man have built automatic toys and mechanism and imagined robots in drawings, books, plays, and science-fiction movies. Robots today, however, are nothing like what was portrayed in many science-fiction movies and stories. Today we find robots working for people in factories, warehouses, laboratories, and even farms. In the future, robots may show up in other places like our homes, schools, and even our bodies.

 

The Czech Play

The human being has always been looking for an easier way to accomplish different tasks. The word robot comes from the Czech word robota, which means drudgery or slave-like labor. This word was first used to describe fabricated workers in a fictional 1920s play by Czech author Karel Capek called Rossum’s Universal Robots (RUR). During the play, a scientist invents robots to help people by performing simple, repetitive tasks. However, once the robots are used to fight wars, they turn on their human owners and take over the world. A robot from that play is shown in figure 2-1.

 

Figure 2-1: RUR

 

 

Early Robots

In the early 1800s mechanical puppets were first built in Europe, just for entertainment value. These were called robots since their parts were driven by linkage and cams and controlled by rotating drum selectors. In 1801 Joseph Maria Jacquard made the next great change and invented the automatic draw loom. The draw loom would punch cards and was used to control the lifting of thread in fabric factories. This was the first to be able to store a program and control a machine. After that there were many small changes in robotics but we were slowly moving forward. One of the first robots however, appeared long before the 1800s.

 

The clepsydra or water clock (shown in figure 2-2) was made in 250 B.C. It was an alarm clock created by Ctesibius of Alexandria, a Greek physicist and inventor. Nikola Tesla built the earliest remote control vehicles in the 1890s. Tesla is best known as the inventor of AC electric power, radio, induction motors, Tesla coils, and other electrical devices. Other early robots (1940s - 50s) were Grey Walter's Elsie the tortoise (Machina speculatrix) and the Johns Hopkins beast.

Figure 2-2: Clepsydra

 

Shakey was a small unstable box on wheels that used memory and logical reasoning to solve problems and navigate in its environment. It was developed by the Stanford Research Institute (SRI) in Palo Alto, California in the 1960s. Refer to table 2-1 for a timeline of robotic development. The General Electric Walking Truck was a large 3 000 pounds four-legged robot that could walk up to four miles an hour. The walking truck was the first legged vehicle with a computer-brain, developed by Ralph Moser at General Electric Corp. in the 1960s. The first modern industrial robots were probably the Unimates, created by George Devol and Joe Engleberger in the 1950s and 60s. Engleberger started the first Robotics Company, called Unimation, and has been called the father of robotics. Robots have since become very popular in the industrialized nations.

Modern Robots

The first industrial robot saw service in 1962 in a car factory run by General Motors in Trenton, New Jersey. The robot lifted hot pieces of metal from a die-casting machine and stacked them. Japan, by comparison, imported its first industrial robot from AMF in 1967, at which time the United States was a good 10 years ahead in robotics technology. The enormous effort put forth by Japanese industry is best evidenced by the fact that Unimation was eventually reduced to handing over its pioneering robot technology to Kawasaki Heavy Industries in a licensing deal in 1968.

 

By 1990, there were more than 40 Japanese companies, including giants like Hitachi and Mitsubishi, which were producing commercial robots. By comparison, there were approximately one dozen U.S. firms, led by Cincinnati Milacron and Westinghouse's Unimation. In 1979 the U.S. leader, Unimation, was the only company in the world actively marketing an advanced assembly robot. In 1982, GM, the largest single user of robots in the world, signed a pact with Fanuc Ltd. for a joint robotics venture to make and market robots in the United States. In the first six months of operation, more than half of the 100 robots sold by the joint venture went to GM, locking out other U.S. companies from the largest single buyer in the market. There were other joint operations. Bendix signed to market Yaskawa robots, while Yaskawa was already selling through Hobart Industries and Nordson Corporation; IBM signed with Seiki to market the SCARA assembly robot, which sells for one-half the price of the Unimation advanced PUMA model but does 85% of what the PUMA does. As of 1987 the U.S. market was valued at more than $170 billion.

 

 

Year Event

1800s USA - Doll writes in two languages and makes simple drawings

1886 USA - A punch card is used for the census. The job is finished in 2.5 years.

1930 USA - The first analog computer for solving differential equations is developed.

1936 Britain - Alan Turing has an idea for a machine for solving logic problems.

1943 ENIAC (Electronic Numerical Integrator and Computer) is the first completely electronic computer, running under instructions from a digital program.

1956 USA - Term ‘Artificial Intelligence (AI)’ is used for the first time.

1959 A laboratory to study AI is started at Massachusetts Institute of Technology (MIT).

1960 First industrial Robot is used, controlled by electronic computers.

1968 First complete robot system is developed at Stanford Research Institute in California. It is a small, wheeled robot called ‘Shakey.’

1980 US industrial robot sales pass the 100 million-per-year mark.

1996 Honda ‘P2’ robot can walk, climb up and down stairs, and keep itself upright if pushed off-balance.

1997 Sojourner robotic explorer roves around on the surface of Mars.

Table 2-1 - Robotic Timeline

 

3 - Benefits of Robots

Robots offer specific benefits to workers, industries and countries. If introduced correctly, industrial robots can improve the quality of life by freeing workers from dirty, boring, dangerous, and heavy labor. In addition robots can save companies a lot of money, improve production rate, and also product quality. Of course, robots take away many jobs from humans but for every job that is taken by a robot, a new one is created because someone needs to design, program, and develop robots.

4 - Uses of Robots

Robots have many uses. They are used for general purpose but also to protect humans from danger. In industry, robots are used in many different industries ranging from food processing to automotive manufacturing. Typical applications include material processing, material handling, assembly welding, spray painting/ coating, die casting, press operations, foundry, inspection, and many more.

Industry

When doing a job, robots can do many things faster than humans can. Robots do not need to be paid, eat, drink, or go to the bathroom like people. They can do repetitive work that is absolutely boring to people and they will not stop, slow down, or fall to sleep like a human. Robots are also more accurate than humans when doing certain tasks. They can accomplish work in a very precise manner.

Figure 4-1: Robot welder

 

 

Exploration

People are interested in places that are sometimes full of danger, like outer space, or the deep ocean.

But when they can not go there themselves, they make robots that can go there. The robots are able to carry cameras and other instruments so that they can collect information and send it back to their human operators.

Figure 4-2: Mars explorer

 

 

Medicine

Sometimes when operating, doctors have to use a robot instead. A human would not be able to make a hole exactly one 100th of an inch wide and long. Robotic surgery is becoming popular as years pass.

The first generation of surgical robots are already being installed in a number of operating rooms around the world. Figure 4-3 shows a graphic of a robotic surgery room. These aren't true autonomous robots that can

Figure 4-3: Robotic surgery room

 

perform surgical tasks on their own, but they are lending a Mechanical helping hand to surgeons. These machines still require a human surgeon to operate them and input instructions. Remote control and voice activation are the methods by which these surgical robots are controlled. Robotics are being introduced to medicine because they allow for unprecedented control and precision of surgical instruments in minimally invasive procedures. So far, these machines have been used to position an endoscope, perform gallbladder surgery and correct gastroesophogeal reflux and heartburn. The ultimate goal of the robotic surgery field is to design a robot that can be used to perform closed-chest, beating-heart surgery.

 

 

According to one manufacturer, robotic devices could be used in more than 3.5 million medical procedures per year in the United States alone. Three different surgical robots that have been recently developed are da vincia surgical system,

Figure 4-4: Robotic surgery end effector

ZEUS robotic surgical system, and AESOP robotic system. When making medicines, robots can do the job much faster and more accurately than a human can. Also, a robot can be more delicate than a human. Some doctors and engineers are also developing prosthetic (bionic) limbs that use robotic mechanisms. Dr. David Gow, of the Prosthetics Research and Development Team at Princess Margaret Rose Orthopaedic Hospital, made the first bionic arm called the Edinburgh Modular Arm System (EMAS) in 1998.

Entertainment

At first, robots were just for entertainment, but as better technology became available, real robots were created. Many robots are still seen on T.V. (Star Trek - The Next Generation) and in the movies (The Day the Earth Stood Still, Forbidden Planet, Lost in Space, Blade Runner, Star Wars). These imaginary robots do a lot of things that the real ones can not do. Some robots in movies are made to attack people, but in real life they cannot really hurt people at all because they are not in control of themselves. Robots also attack humans in video and computer games.

Military and Police

Police need certain types of robots for bomb-disposal (figure 4-5) and for bringing video cameras and microphones into dangerous areas, where a human policeman might get hurt or killed. The military also uses robots for: locating and destroying mines on land and in water, entering enemy bases to gather information, and for spying on enemy troops.

 

Figure 4-5: Bomb disposal robot

 

Toys

The new robot technology is making interesting types of toys that children will like to play with. One new robotic toy is the "FURBY", which became available in stores for Christmas 1998 - and continues to be very popular.

Figure 4-6: Lego Mindstorms

 

 

Another is the "LEGO MINDSTORMS" robot construction kit. These kits, which were developed by the LEGO Company with M.I.T. scientists, lets kids create and program their own robots. Students at various colleges and universities use Lego mindstorms for engineering design purposes. A third is "Aibo" - Sony Corporation's robotic dog. Sony is selling limited numbers of Aibo in the U.S. Also remote controlled cars toys are very popular.

 

5 - Industrial Robots

The most usefull robots in the world are designed for heavy, repetative manufacturing work. They handle tasks that are difficult, dangerous, or boring to human beings. One particular robot, the robotic arm, is the most common manufacturing robot used. Robotic arms are shown in figure 5-1 working in an assembly line at General Motors. The robotic arm is used in a variety of industries ranging from food-procecessing to automotive manufacturing plants.

They are used for tasks such as moving and filling a bag of salt to welding the body of a car. Robots, like machine tools, are available in a variety of types, styles, and sizes. Generally, they are described as either servo or non servo.

Figure 5-1: Automotive manufacturing

 

Classifications

Industrial robots, are generally classified by:

 Arm configuration and reach.

 Power source and programmable speed.

 Load capacity.

 Application capabilities.

 Control technique and intelligence.

Configurations

Although, for the most part related to mechanical engineering and not electrical engineering. The following configurations are an important part of this report. The basic mechanical configurations of the robot are:

Cartesian Geometry

A robot with Cartesian geometry is able to move its gripper to any position within the cube or rectangle defined as its working volume. The rectangular work envelope of this type of robot is often used to move parts from a conveyor system into production machines.

Cylindrical Geometry

Cylindrical robot systems can move within a volume that is described by a cylinder. The cylindrical coordinate robot is positioned in the work area by two linear movements in the X and Y directions and one angular rotation about Z-axis.

Spherical Geometry

Spherical geometry arm robot robot position the wrist through two rotational and one linear actuation. This type of robots was used in early industrial applications.

Articulated Geometry

The jointed arm robots have an irregular work envelope, it has two main variants, vertically articulated and horizontally articulated. This Milacron Robot in figure 5-2 image is from Robots by Henson.

 

Figure 5-2: Articulated Geometry

Industrial Robotic System

The basic robot system includes a mechanical arm to which the end-of-arm tooling is mounted, a computer-based controller with attached tech station, work cell interface, and a program storage device. In addition, a source of pneumatic and/or hydraulic power is a part of the basic system.

Figure 5-3 – Industrial Robotic System

 

 

The work cell system connects to the robot through the robot work cell interface. Figure 5-3 above shows a diagram of a basic robotic system.

 

Selection and Justification for Applications

Integrating an industrial robot into an existing production station requires a detailed design process. The cost of a robot automation project depends on the complexity of the cell, the quantity and quality of existing production equipment, and the type of the robot selected.

 

Steps in Robotic Cell Development

1. Pick the best manufacturing situation for the implementation.

2. Pick the best robot for the specific job identified in step one.

3. Build the best work cell possible around the robot selected.

 

Computer Integrated Manufacturing

The robot is a part of the total CIM architecture and must be interfaced with the work-cell hardware and with the enterprise wide network. The architecture for the servo-controlled robot system includes a CPU, memory, peripheral input-output, discrete input-output, power supply, axes drivers, and feedback signal conditions.

 

The Robotic Arm

The most common manufacturing robot is the robotic arm. The typical robotic arm is made up of seven metal segments, joined by six joints. Industrial robots with six joints closely resemble a human arm – it has the equivalent of a shoulder, an elbow and a wrist. A robotic arm is shown in figure 5-4.

Figure: 5-4 – Robotic Arm

 

 

Degrees of Freedom

The robotic arm robot has six degrees of freedom, meaning it can pivot in six different ways. A human arm, by comparison, has seven degrees of freedom. The following are the degrees of freedom of a robotic arm. In figure 5-5, the arrows show the directions of rotation of the degrees. Notice how the wrist can move in three different directions.

 1st degree – Base rotation (left & right)

 2nd degree – Pivot arm base (up & down)

 3rd degree – Bend elbow (up & down)

 4th degree – wrist up and down

 5th degree – wrist left and write

 6th degree – rotate wrist

Figure 5-5: Degrees of freedom

 

Driving Methods

Drives are the source of motive power that drives the links to a desired position. Usually power is applied at the joints, directly or through cables, gearing, belts, or other means. There are four types of popular drive used in robotic systems today: Hydraulic, Pneumatic, DC electric motors, and Stepper electric motors.

Hydraulic drives:

Hydraulic drives in robots use oil under high pressure as the working fluid. Drives may be open loop or closed loop. Open loop drives can go from point to point accurately but cannot be controlled to stop at points in between. The main advantage of hydraulic drives over electrical drives is their safe operation. In certain industrial manufacturing processes electrical drives, if not sealed off, can be a danger because they can result in arcing or explosive reactions. Therefore, hydraulic drives are often used to avoid these situations. Hydraulic drives also need a pump to pressurize the fluid. Hydraulic drives like any other driving methods are wired to an electrical circuit. The circuit powers motors and solenoids directly, and it activates the hydraulic system by opening or closing electrical. The valves of course, can also be opened and closed manually.

Pneumatic drives

Pneumatic drives are the simplest of all drives. They are widely used in industry for many types of applications. Pneumatic drives are very similar to hydraulic ones, but vary considerably in detail. The working fluid of pneumatic drives is compressed air. Valves for pneumatic drives are simpler and less expensive than hydraulic ones. The pressures used are also much smaller. Pneumatic drives are lightest in weight and lowest in cost. Programmable controllers are often used for control with pneumatic systems. The controllers are usually microprocessors programmed to emulate relay systems.

DC Electric Motors

The motion of DC motors is smooth and continuous. A typical DC motor is shown in figure 5-6. DC motors are usually used in robots where precision and high power is required. Precise control of positioning in DC motors requires that a closed-loop servo be used with some type of positional feedback.

When controlled in a closed loop method, smooth operation and the ability to produce high torque is possible. In addition DC motors are also capable of high precision, fast acceleration, and high reliability.

Figure 5-6: Electric DC Motor

 

Torque control in DC motors can be achieved by controlling current in the DC motor with the use of a current amplifier.

 

Usually power supply available in industrial plants is single-phase or three-phase AC at 60Hz cycles at nominal voltages of 110, 220, or 440 volts. Power converters are required to convert this AC to DC in order to operate DC electric motors required to drive the robots. After conversion, the DC must be regulated to a reasonable constant voltage level and applied to a power amplifier or a switching circuit, which controls the current or voltage direction of power applied to the drive motors. Three types of circuits are used: rectifiers, power regulators, and power amplifiers. The steps in converting AC to DC is as follows:

Step 1: Input from an AC source is fed into a transformer (step-down transformer – usually) that changes the input voltage to a desired level. The output of the transformer is still AC.

Step 2: It is passed through a rectifier to convert it to DC. The step-down transformer and the rectifier are a single circuit as shown in figure 5-7. The output of the rectifier is a DC varying voltage level.

 

Figure 5-7: Rectifier

 

Step 3: The output of the rectifier is an unregulated power. It is passed through another circuit that stabilizes the voltage to a nearly constant value and applies it to a load. This can be achieved through filtering or by providing negative feedback. Filtering is done by putting large inductances in series with a current flow and large capacitors in parallel with both the input and the output. In the negative feedback method, voltage that opposes the high voltages and enhances the low voltages to generate a nearly constant output level, is fed back to the op-amp. A complete AC to DC converted is shown below in figure 5-8 using a voltage regulator and bridge rectifier.

 

Figure 5-8: Complete AC to DC Conversion

 

 

Electric Stepper Motors

Stepper motors are used in robots for applications where precise open-loop control and low torque is required. Stepper motors can be controlled in precise increments using electrical pulses, which allow the controller to move a robotic very precisely, repeating the same steps over and over again. Another attractive feature of stepper motors is that they respond to digital signals very well. On figure 5-9 a digital circuit is shown that can be used to control a stepper motor.

 

Figure 5-9: Stepper motor control

 

The circuit consists of resistors, inductors, diodes, and transistors. There are also two TTL logic gates used in the circuit, an inverter and an EX-OR gate (74LS86). The EX-OR gate is used as the input to the circuit. It produces a HIGH logic level for different input conditions and a LOW for the same logic levels. Since the gate has two inputs, four different output conditions can be achieved (22 = 4). The inverter is used to produce the right logic levels for the 4 coils. For example, When both inputs to the EX-OR are low, its output is LOW. The low output is fed through an inverter whose output forward biases transistor Q1. Transistor Q1s collector then energizes coil A. For the same input condition, one of the low inputs to the EX-OR gate is also fed through a different inverter to energize coil B. Therefore, when the input conditions are low, coils A and B are energized. On table 5-1, the full truth table is shown for all possible input conditions for the ex-or gate.

D1 D0 Q (COILS)

0 0 A, B

0 1 B, C

1 0 C, D

1 1 D, A

Table 5-1: Coils

This circuit described is good for a motor requiring up to 500mA. Obviously, this amount of current is not enough to produce the power required by an industrial machine. Rather this is good enough to operate a fax machine or a printer but not enough for a robot. More current can be achieved by replacing the BJT transistors with power transistors, such as Darlington pairs. The diodes in the circuit are to protect the circuit from transients. A two-bit up/down counter can be to this added circuit to control the direction and a 555 timer in the astable mode of operation can be used to control the speed.

 

 

6 - Radio Controlled (RC) Toys

RC toys come in a large variety of models, including cars, trucks, fantasy vehicles, airplanes, helicopters (shown is figure 6-1), robots – just to name a few. Different RC toys can go different speeds. High speeed RC toys of over 20 miles per hour exist.

Figure 6-1: Helicopter

 

How RC Toys Work

While the mechanics of how they operate can differ greatly between different toys, the basic principle is the same. All radio-controlled toys have four main parts, which include the transmitter, receiver, motors, and power source. A brief description of each is given in table 6-1 below.

Component Description

Transmitter You hold the transmitter in your hands to control the toy. It sends Radio waves to the receiver.

Receiver An antenna and circuit board inside the toy receives signals from the transmitter and activates motors inside the toy as commanded by the transmitter.

Motor(s) Motors can turn wheels, steer the vehicle, operate propellers, etc.

Power source The power source powers the motors.

Table 6-1: RC toy main parts

The Transmitter

RC toys typically have a small handheld device that includes some type of controls and the radio transmitter. The transmitter sends a signal over a frequency to the receiver in the toy. The transmitter has a power source, usually a 9-volt battery that provides the power for the controls and transmission of the signal. The key difference between radio controlled and remote controlled toys is that remote controlled toys have a wire connecting the controller and the toy, while radio control is always wireless. Most RC toys operate at either 27 MHz or 49 MHz. The FCC has allocated this pair of frequencies for basic consumer items, such as garage door openers, walkie-talkies and RC toys. Advanced RC models, such as the more sophisticated RC airplanes, use 72 MHz or 75 MHz frequencies. Manufacturers make versions of each model for both frequencies ranges (27 MHz and 49 MHz).

 

That way, you can operate two of the same model simultaneously, for racing or playing together, without having to deal with interference between the two transmitters. Some manufacturers also provide more specific information about the exact portion of the frequency band that the toy operates in.

 

Figure 6-2: Controller

 

 

A good example is Nikko of America, who offers the option to create racing sets of up to six toys with each model tuned to a different part of the 27-MHz frequency range. Transmitters range from single-function simple controllers to full-function controllers with a wide range of options. An example of a single-function controller is one that makes the toy go forward when the trigger is pressed and backward when it is released. To stop the toy, you have to actually turn it off.

 

RC Toy Controllers

Most full-function controllers have six controls including forward, reverse, forward and left, forward and right, reverse and left, and reverse and right.

In most full-function controllers, not pressing any buttons or turning any knobs causes the toy to stop and await further commands. Controllers for more advanced RC systems often use dual joysticks with several levels of response for precise control.

 

Radio Control Pulse Segment

We will assume that the exact frequency used is 27.9 MHz. Each sequence contains a short group of synchronization pulses, followed by the pulse sequence. For our receiver in the toy, the synchronization segment -- which alerts the receiver to incoming information -- is four pulses that are 2.1 milliseconds (thousandths of a second) long, with 700-microsecond (millionths of a second) intervals. The pulse segment, which tells the antenna what the new information is, uses 700-microsecond pulses with 700-microsecond intervals.

 

Here are the pulse sequences used in the pulse segment:

Forward: 16 pulses, Reverse: 40 pulses, Forward/Left: 28 pulses, Forward/Right: 34 pulses, Reverse/Left: 52 pulses, and Reverse/Right: 46 pulses.

 

 

 

 

Figure 6-3: Pulse segments

 

A: Pulse sequence, B: 29.7Mhz signal, C: Transmitting Signal, D: 4 Synchronization bursts each is  2.1ms long, width is  700s spacing, E: Burst sequence each is  700s long, width is  700s, F: Sequence repeats.

 

The transmitter sends bursts of radio waves that oscillate with a frequency of 27,900,000 cycles per second (27.9 MHz). Then the receiver (in the toy) is constantly monitoring the assigned frequency (27.9 MHz) for a signal. When the receiver receives the radio bursts from the transmitter, it sends the signal to a filter that blocks out any signals picked up by the antenna other than 27.9 MHz. The remaining signal is converted back into an electrical pulse sequence. Next pulse sequence is sent to the IC in the truck, which decodes the sequence and starts the appropriate motor. For our example, the pulse sequence is 16 pulses (forward), which means that the IC sends positive current to the motor running the wheels. If the next pulse sequence were 40 pulses (reverse), the IC would invert the current to the same motor to make it spin in the opposite direction. The motor's shaft actually has a gear on the end of it, instead of connecting directly to the axle. This decreases the motor's speed but increases the torque, giving the truck adequate power through the use of a small electric motor!

Inside of an RC Truck

Figure 6-4 below shows the inside of a RC truck. The figure shows that it is fairly simple: two electric motors, an antenna, a battery pack and a circuit board.

One motor turns the front wheel right or left, while the other motor turns the rear wheels to go forward or backward. The circuit board contains the IC chip, amplifier and radio receiver. A few simple gears connect the motors to the wheels. It is really amazing how versatile the range of movement is with so few components.

 

Figure 6-4: Inside an RC truck

 

 

Part of RC models

The body of RC models consists of a lower chassis, that holds all the mechanical and electronic components, and a shell that fits on top of the chassis. The shell provides most of the distinctive style of the car. Inside the car, you will find a circuit board with several capacitors, resistors and diodes, as well as the IC that controls the motors. The radio receiver consists of a crystal that oscillates at a specific frequency, inductors and an antenna. The electric motors receive power from the batteries. The IC regulates the flow of the power.

 

Transmitting Information

If you have a sine wave and a transmitter that is transmitting the sine wave into space with an antenna, you have a radio station. The only problem is that the sine wave doesn't contain any information. You need to modulate the wave in some way to encode information on it. There are three common ways to modulate a sine wave Pulse Modulation, Amplitude Modulation, and Frequency Modulation. They are described in detail below.

Pulse Modulation (PM)

In PM, you simply turn the sine wave on and off. This is an easy way to send Morse code. PM is not that common, but one good example of it is the radio system that sends signals to radio-controlled clocks in the United States. One PM transmitter is able to cover the entire United States!

 

Figure 6-5: PM

 

Amplitude Modulation (AM)

Both AM radio stations and the picture part of a TV signal use amplitude modulation to encode information. In amplitude modulation, the amplitude of the sine wave (its peak-to-peak voltage) changes. So, for example, the sine wave produced by a person's voice is overlaid onto the transmitter's sine wave to vary its amplitude.

 

Figure 6-6: AM

 

Frequency Modulation (FM)

FM radio stations and hundreds of other wireless technologies (including the sound portion of a TV signal, cordless phones, cell phones, etc.) use frequency modulation. The advantage to FM is that it is largely immune to static. In FM, the transmitter's sine wave frequency changes very slightly based on the information signal.

 

Figure 6-7: FM

 

Once the sine wave is modulated the information can be transmitted using a transmitter.

Radio Spectrum

A radio wave is an electromagnetic wave propagated by an antenna. Radio waves have different frequencies, and by tuning a radio receiver to a specific frequency you can pick up a specific signal. In the United States, the FCC (Federal Communications Commission) decides who is able to use which frequencies for which purposes, and it issues licenses to stations for specific frequencies.

 

When you listen to a radio station and the announcer says, "You are listening to 91.5 FM WRKX The Rock!," what the announcer means is that you are listening to a radio station broadcasting an FM radio signal at a frequency of 91.5 megahertz, with FCC-assigned call letters of WRKX. Megahertz means "millions of cycles per second," so "91.5 megahertz" means that the transmitter at the radio station is oscillating at a frequency of 91,500,000 cycles per second. Your FM (frequency modulated) radio can tune in to that specific frequency and give you clear reception of that station. All FM radio stations transmit in a band of frequencies between 88 megahertz and 108 megahertz. This band of the radio spectrum is used for no other purpose but FM radio broadcasts. In the same way, AM radio is confined to a band from 535 kilohertz to 1,700 kilohertz (kilo meaning "thousands," so 535,000 to 1,700,000 cycles per second). So an AM (amplitude modulated) radio station that says, "This is AM 680 WPTF" means that the radio station is broadcasting an AM radio signal at 680 kilohertz and its FCC-assigned call letters are WPTF.

Common frequency bands include the following:

Type Frequency bands

AM radio 535 kHz to 1.7 Mhz

Short wave radio bands from 5.9 Mhz to 26.1 Mhz

Citizens band (CB) radio 26.96 Mhz to 27.41 Mhz

Television stations 54 to 88 Mhz for channels 2 to 6

FM radio 88 Mhz to 108 Mhz

Television stations 174 to 220 Mhz for channels 7 to 13

Table 6-2: Common frequency bands

Wireless technology has its own little band. There are hundreds of them! For example:

Wireless Technology Frequency bands

Garage door openers, alarm systems, etc. Around 40 megahertz

Radio controlled airplanes: Around 72 megahertz

Radio controlled cars: Around 75 megahertz

Cell phones: 824 to 849 megahertz

Deep space radio communications: 2290 megahertz to 2300 megahertz

Table 6-3: Wireless frequency bands

 

Radio Scanners

The air around you is bursting with radio waves. You know that you can flip on the AM/FM radio in your car and receive dozens of stations. You can flip on a CB radio and receive 40 more. You can flip on a TV and receive numerous broadcast channels. Cell phones can send and receive hundreds of frequencies. And this is just the tip of the radio spectrum iceberg. Literally tens of thousands of other radio broadcasts and conversations are zipping past you as you read this article -- police officers, firefighters, ambulance drivers, paramedics, sanitation workers, space shuttle astronauts, race car drivers, and even babies with their monitors are transmitting radio waves all around you at this very moment!

 

To tap into this ocean of electromagnetic dialog and hear what all of these people are talking about, all you need is a scanner. A scanner is basically a radio receiver capable of receiving multiple signals. Generally, scanners pick up signals in the VHF to UHF range

 

Scanners typically operate in three modes, which are scan, manual scan, and search. In scan mode, the receiver constantly changes frequencies in a set order looking for a frequency that has someone transmitting. Lights or panel-mounted displays show what channel or frequency is in use as the scanner stops on a given frequency. The frequencies can be preprogrammed on some models or manually set on practically all models. In manual scan mode, the user taps a button or turns a dial to manually step through preprogrammed frequencies one frequency at a time. In search mode, the receiver is set to search between two sets of frequencies within a given band. This mode is useful when a user does not know a frequency, but wants to know what frequencies are active in a given area. If the frequency the scanner stops at during a search is interesting, the user can store that frequency in the radio scanner and use it in scan mode.

 

 

7 - Robots in the Future

Robots are here to stay. In the future they will be used more in space-exploration. Future missions to space will include many robotic vehicles designed to perform specific tasks both autonomous and remote controlled. They will be used more and more in combat and intelligence gathering by the military. We will also see more automation in plants. The robots of the future will be much smarter than the ones we know today. Robots will be able to hold more information and even learn on a limited basis through the use of artificial intelligence.

Artificial Intelligence (AI)

Artificial intelligence is arguably the most exciting field in robotics. It's certainly the most controversial: Everybody agrees that a robot can work in an assembly line, but there's no consensus on whether a robot can ever be intelligent.

 

Like the term "robot" itself, artificial intelligence is hard to define. Ultimate AI would be a recreation of the human thought process -- a man-made machine with our intellectual abilities. This would include the ability to learn just about anything, the ability to reason, the ability to use language and the ability to formulate original ideas. Roboticists are nowhere near achieving this level of artificial intelligence, but they have had made a lot of progress with more limited AI. Today's AI machines can replicate some specific elements of intellectual ability.

Computers can already solve problems in limited realms. The basic idea of AI problem-solving is very simple, though its execution is complicated. First, the AI robot or computer gathers facts about a situation through sensors or human input. The computer compares this information to stored data and decides what the information signifies. The computer runs through various possible actions and predicts which action will be most successful based on the collected information. Of course, the computer can only solve problems it's programmed to solve -- it doesn't have any generalized analytical ability. Chess computers are one example of this sort of machine.

 

Some modern robots also have the ability to learn in a limited capacity. Learning robots recognize if a certain action (moving its legs in a certain way, for instance) achieved a desired result (navigating an obstacle). The robot stores this information and attempts the successful action the next time it encounters the same situation. Again, modern computers can only do this in very limited situations. They can't absorb any sort of information like a human can. Some robots can learn by mimicking human actions. In Japan, roboticists have taught a robot to dance by demonstrating the moves themselves.

 

The real challenge of AI is to understand how natural intelligence works. Developing AI isn't like building an artificial heart -- scientists don't have a simple, concrete model to work from. We do know that the brain contains billions and billions of neurons, and that we think and learn by establishing electrical connections between different neurons. But we don't know exactly how all of these connections add up to higher reasoning, or even low-level operations. The complex circuitry seems incomprehensible.

 

 

8 Conclusion

 

Robots have proven to be very useful to us. The dream of a tireless servant that mankind has always imagined in fairytales, movies, and short stories have finally come true in last few decades. Early although not too advanced have helped shape the way for robots, as we know them today. Modern robots are excellent workers that unlike the human worker don’t get tired. In addition robots free the human worker from dirty, boring, and hazardous work.

 

Robots are used for many different applications including industry, exploration, medicine, entertainment and toys, and military and police. Industrial robots by far are the most useful types of robots that have been developed. As mentioned before they free workers from undesirable work. Industrial robots come in many different configurations and should be carefully chosen for the particular application. In addition industrial robots can be easily integrated with existing system in an industrial plant. They can be made to communicate with existing systems through the use of computer systems.

 

The robotic arm is the most popular industrial robot used. It is used in many different industries for various tasks. They come in all kinds of sizes and with different kinds of end effectors. The robotic arm closely resembles the arm of a human being but has one less degree of freedom. Various driving methods are used to power the robotic arm including hydraulic, pneumatic, and various electrical methods. Electronic circuits and systems are used to control a robotic arm. Some of the circuitry used are circuits used to control the speed, direction, and the amount and type of electrical power that is fed into the system. For conversion purposes of the electrical power that is fed into a robotic system, two main circuits are used, which are positive feedback and filtering.

 

Robots have a lot to do with various communications methods. For radio controlled toys three methods are used including Amplitude Modulation and Frequency Modulation. Wireless technology has its own frequency band assigned by the FCC. Typically RC planes operate at a frequency of 72Mhz and radio-controlled cars at around 75Mhz. By comparison cell phones operate at 824 to 849Mhz.

 

 

BIBLIOGRAPHY

 

 David, Jefferis. Artificial Intelligence – Robotics and Machine Evolution. New York: Grabtee Publishing Company, 1999

 Todd, D. J. Walking Machines – An Introduction to two-Legged Robots. New York: Chapman & Hill, 1985

 Everett, H.R. Sensors for Mobile Robots - Theory and Application.

Massachusetts: A K Peters, Ltd, 1995.

 Malcolm Jr, Douglas R. Robotics – An Introduction, Boston, Massachusetts: Breton Publishers, 1985

 Critchlow, Arthur J. Introduction to Robotics. New York: Macmillan Publishing company, 1986

 Floyd L, Thomas. Electronic Devices – Sixth Edition. Columbus, OH: Prentice Hall, 2002

 Bartelt, Terry. Industrial Control Electronics – Devices, Systems, and Applications. Albany, NY: Delmar Thompson Learning, 2002

 Miller M. Gary and Beasley S. Jeffrey. Modern Electronic Communications – Seventh Edition. Columbus, OH: Prentice Hall. 2002

 “Electronics World”

April 4, 2003

 “Robot Automation”

April 4, 2003

 “Robot Arm Technology”

April 3, 2003

 “Programmable Robotic Arm”

Apr 12, 2003

 “Robotic Control and Communication”

April 10, 2003

 “Robot Controllers”

April 17, 2003

[Caano Geel]

hello i'm an AI and Robotics person if you need any help get in contact

[mojam]

Caano Geel. Thanks a lot for offering to help me. This was just a one-time assigment I did on Robots but i'm not really planning to get into this field. I'm more geared towards communications. Are you working as an electrical engineer?