ROBOTICS...

ROBOT TRAITS

2008-01-08T07:40:00.000-08:00

ROBOT
Pronunciation: 'rO-bot'
Function: noun
Etymology: Czech, from robota compulsory labor; akin to Old High German arabeit trouble, Latin orbus orphaned
Date: 1923

1a : a machine that looks like a human being and performs various complex acts (as walking or talking) of a human being; also : a similar but fictional machine whose lack of capacity for human emotions is often emphasized
b : an efficient insensitive person who functions automatically

2 : a device that automatically performs complicated often repetitive tasks

3 : a mechanism guided by automatic controls

A robot can be defined as a programmable, self-controlled device consisting of electronic, electrical, or mechanical units. More generally, it is a machine that functions in place of a living agent. Robots are especially desirable for certain work functions because, unlike humans, they never get tired; they can endure physical conditions that are uncomfortable or even dangerous; they can operate in airless conditions; they do not get bored by repetition; and they cannot be distracted from the task at hand.

The concept of robots is a very old one yet the actual word robot was invented in the 20th century from the Czechoslovakian word robota or robotnik meaning slave, servant, or forced labor. Robots don't have to look or act like humans but they do need to be flexible so they can perform different tasks.

Early industrial robots handled radioactive material in atomic labs and were called master/slave manipulators. They were connected together with mechanical linkages and steel cables. Remote arm manipulators can now be moved by push buttons, switches or joysticks.

Current robots have advanced sensory systems that process information and appear to function as if they have brains. Their "brain" is actually a form of computerized artificial intelligence (AI). AI allows a robot to perceive conditions and decide upon a course of action based on those conditions.

A robot can include any of the following components:

effectors - "arms", "legs", "hands", "feet"
sensors - parts that act like senses and can detect objects or things like heat and light and convert the object information into symbols that computers understand
computer - the brain that contains instructions called algorithms to control the robot
equipment - this includes tools and mechanical fixtures

Characteristics that make robots different from regular machinery are that robots usually function by themselves, are sensitive to their environment, adapt to variations in the environment or to errors in prior performance, are task oriented and often have the ability to try different methods to accomplish a task.

Common industrial robots are generally heavy rigid devices limited to manufacturing. They operate in precisely structured environments and perform single highly repetitive tasks under preprogrammed control. There were an estimated 720,000 industrial robots in 1998.

Teleoperated robots are used in semi-structured environments such as undersea and nuclear facilities. They perform non-repetitive tasks and have limited real-time control.

Robots are especially valuable to space exploration. Not only can they travel to environments too hostile or too distant for human explorers, but they can also enhance the work schedule of a manned space mission. Space telerobots perform non-repetitive tasks in semi- to unstructured environments. There is often a variable time delay for instructions between the operator and the robot. These robots need to be dexterous, lightweight and have flexible manipulators. They are usually deployed in hostile environments with excessive heat, radiation, a vacuum and variable lighting. These robots must be able to recover from unplanned events including system faults and errors.

BUILDING A RF REMOTE CONTROL

2008-01-04T00:56:00.000-08:00

Guys this is a circuit for a RF robot..It has been taked directly from TRI site..
This is much simpler and easier to make..check it out

Ever wondered how you can get rid of that long wired tail dangling out of your remote control robot? Well, transforming your wired remote control into a wire-less one isn’t as difficult as you may think!
The easiest solution would be to hack those cheap wireless toy cars, take their electronic guts out and use them in your robot. But if you want more flexibility, you can build a custom remote control system. And here’s an article on how we are going to do that:

The idea is to use off-the-shelf RF Tx/Rx modules. These modules, once a rare commodity, are now widely and cheaply available. In this particular discussion, we shall be using ASK (Amplitude Shift Keying) based TX/RX pair operating at 433 MHz. The transmitter module accepts serial data at a maximum of XX baud rate.
They can be directly interfaced to a microcontroller or can be used in remote control applications with the help of encoder/decoder ICs. The encoder IC takes in parallel data at the TX side, packages it into serial format and then transmits it with the help of a RF transmitter module. At the RX end, the decoder IC receives the signal via the RF receiver module, decodes the serial data and reproduces the original data in the parallel format.

ASK Transmitter ASK Reciever

Now in order to control say one motor, we require 2 bits of information while we need 4 bits of information to control 2 motors. HT12E and HT12D are 4 channel encoder/decoder ICs directly compatible with the specified RF module. The schematic is as shown below

In order to drive motors, we would need to connect a suitable motor driver at the output of the decoder IC. The motor driver circuit can consist of a Relay, transistorized H-Bridge or motor driver ICs like the L293D, L298 etc.

Datasheets:HT12E

HT12D

BEETLE BOT

2008-01-04T00:35:00.000-08:00

A Simple Beetle Bot For Begineers

Tools Needed:

soldering iron ( here's a helpful tutorial on soldering )
electronic solder
diagonal cutter
Mini glue gunComponents for the robot
2x - small 1.5 Volts motors
2x - small paperclips
2x - big paperclips
2x - batteries AAA or AA
1x - battery holder AAA or AA
1x - 2 cm of heat shrink
1x - wooden pearl (for the caster)
1x - meter of electric wire
2x - Sub-mini lever SPDT switches

Here are the serial numbers of the components and tools from RadioShack .
Component
Number
soldering iron
64-2184
electronic solder
64-006
diagonal cutter
64-2951
1.5 Volts motor
273-223
battery holder
270-398
SPDT switch

275-016 Most of the components can be bought for much cheaper at Digi-Key, Jameco, or similar. At Solarbotics you can find the dual AA battery holder and the Mabuchi motor. You can find these components at any good electronic store.Here is all the parts for the construction the beetle robot.

1. Cut the electric wires in pieces of 6cm each , 13 times

Strip 1 cm at each end

2. Regroup all the components.

3. Solder each wire to each components except the two batteries.

4. Take the battery holder and make a connection to the connection.

This will give a third connection.See picture below.

The blue wire is the third connections

5. Turn the battery holder up side down so the batteries point to the ground. Glue the two switches on the battery holder in V form.

6. Glue the motor beside each switch so that the shaft touches the ground

7. Take the big paperclip and make the caster like the picture below.

You can make a nice looking caster or a normal one

I prefer the nice one

8. How to make the connection

9. Take the small paper clip and bend them to make antenna.

Glue them to the switches and don't put to much glue.

Add 1 cm of heat shrink to the shaft of each motor.

10. Add the batteries in the battery holder and put it on a flat surface to see your creation take life.

BEGINNERS ROBOT

2008-01-04T00:14:00.000-08:00

For the basic Robot(level-1)

First of all lets understand the DC motors.

DC motors are geared motors. These contain a Gear box at the top and the silver coloured part in the picture is the main motor that drives the axle.
as u can see in the first fig. to the extreme left . there are various gears in it. these are step gears which reduce the high r.p.m to the desired r.p.m
The main motor gives around 2000 r.p.m whereas the gear box reduces it to the desired r.p.m { 15 r.p.m in this case }
Now, one thing to keep in mind that the Torque is inversly proportional to the speed.
TORQUE = k/ SPEED

where k is a constant.
In a laymans language Torque is the power given by the motor to overcome the obstacle.
If you want high speed then u have to compromise with the Torque and if u want high torque than compromise with the speed.
Generally for normal robotics competition {level 1} one should go for 300 r.p.m motors as they provide you the combination of torque as well as speed.
I hope you guys got the concept of torque and speed by now..

DRIVE FOR ROBOT:

You can use any material for the body of your robo. It can be either wood, M.S plate. Aluminium, etc. depending upon the weight requirements
Generally the cars on our roads are rear wheel drive. But for the competitions this won’t serve the purpose.Let us see the disadvantages In the fig the one with dark rear wheel is rear wheel drive while the other is four wheel drive.{ ie. All the four wheels powered by motors }
How do the robo car overcome an obstacle ? When a car is moving the wheel rotates in clockwise direction while moving forward. and hence the friction force acts in anticlockwise direction. This makes the car move forward. Similarly it overcomes an obstacle. Now if the car is climbing an inclined plane. Then in case of rear wheel drive there will be no friction force on the front wheels because they r not powered and hence unable to generate a reaction. Due to this the car will topple upside down.
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Same is the case while clearing an obstacle in rear wheel drive and it won’t be able to clear it.
But in four wheel drive each wheel generates a reaction . and there acts a friction force. Hence it is able to clear all the obstacles as well as climb the inclination with higher degree than that of rear wheel drive car.
The very fact that Centre of gravity plays an important role .
The C.G ON A FOR WHEEL DRIVE ACTS ON THE CENTRE OF THE BODY.
ON REAR WHEEL DRIVE IT ACTS BETWEEN THE TWO MOTORS.
by adding some dead weight on the front side and shifting the C.G somewhere in between can serve the purpose in rear wheel drive.

The very common example can be a normal four wheeler and a HUMMER. Hummer is a four wheel drive vehicle hence can even climb uneven terrains..
we can also use a belt as used in tanks on wheels as it can be seen in the pic. above. but again this har advantage on the sand. what is observed during robotics competitions is that the belt comes off while overcoming an obstacle or by excessive jerks. hence it is advisable to avoid such method.
For normal competitions in robotics we need to clear a track in minimum possible time or win a knockout race. So we need speed as well as enough torque to overcome all obstacles. As I wrote on my last post a 300 r.p.m motor would serve both purpose and also it should be a four wheel drive.

CIRCUITRY:

The circuitry of a normal robotic car. This circuitry will enable the robo to move forward, backward, left and right. Now starting with circuitry we need 2 two way switches. These switches conduct in both directions hence the name two way switches. Firstly we sort the terminals
1 and 6 { first switch}
2 and 5 { “ }
1’ and 6’ { second switch}
2’ and 5’ { “ } T
hen we choose the terminals of first switch ie. 5 as positive or 6 as positive . either way one wants to, can do so. But one thing has to be kept in mind that if 5 is positive in 1st switch then 5’ should be the + ve terminal of 2nd switch. The same convention for negative terminal. POWER SUPPLY
Terminals 3,4 from 1st switch and terminals 3’, 4’ from 2nd switch are the power supply terminals. In this too we have to use the same convention like the +ve and –ve terminals of either switches. If we take 3 as +ve than we have to take 3’ as +ve and give this combined combination to the powe supply as +ve. The same case for negative ie. Combination of 4 and 4’ for negative. Or the reverse can also be done.
The terminals 3 and3’ are sorted with the help of wires and similarly we sort the terminals 4 and 4’. The output single wire from 3 and 3’ combination will be given to + ve of the power supply and the output single wire from the combination of 4 and 4’ will be given to the – ve of the power supply.
Power supply can be an adaptor or an eliminator of 12 volts. This is the connection we make in switch. Now how to proceed with combining this connection with motors. MOTOR CONNECTION We will call the top and bottom motors on left hand side the left pair and The top an bottom motors on right side the right pair The above picture shows the left pair .
similarly we have to connect the right pair. LEFT PAIR MOTORS We will bring together the positive of both the top and bottom motor on left hand side and sort them . similarly we will sort the negative of both the motors of the left pair. RIGHT PAIR MOTORS Now as we did in the left pair we will sort the +ve wire of both motors together and sort the –ve of the motors .
So in all we get 4 output wires from the motor connection . 2 from left pair and 2 from right pair.
COMBINING THE SWITCH AND MOTOR CIRCUIT Now to connect the switch to motors we have to choose four output from the switch connection as we have four output from the motor connection.
We will consider the terminal 5 and 6 from the first switch and 5’ and 6’ from second switch. Considering the terminal 5 from first switch positive terminal 5’ will be positive from second switch. Similarly 6 and 6’ are considered as negative.
Now the connection goes this way positive wire combination from left pair motors will be connected to point 5 negative wire combination from left pair motors will be connected to point 6 positive wire combination from right pair will be connected to point 5’ negative wire combination from right pair will be connected to point 6’ these connections are made with the help of intermediate wires called the rainbow wires.
I suppose….. these are a bunch of thin wires used for internal circuitry. If suppose u connect positive wire from left hand pair from motors to red wire then the other end of red wire will be connected to point 5.
Similarly for all connections. The length of the intermediate wire depends on the user. Normally we take 8 to 9 meters. That will be the range of your robo.