Monday, 5 April 2010

Vertical Limit concept bot

Here's a ONE concept robot i sketched for the Vertical Limit event :



Concept

The robot has 2 swinging arms attached to the main chassis of the robot. The swinging arms each has one or more rotating tires attached to them for gripping & climbing the poles. A simple hook mechanism is attached at the end of the swinging arms to push the ping pong ball into the basket.

Motors

  1. 1 motor for moving the robot front and back with no turning ability. (since that's all you need to move from pole A to pole B)
  2. 1 motor for swinging the arms to the front to hold on to pole A and swinging to the back to hold on to pole B.
  3. 1 motor for the rotating tires on the swinging arms for climbing the poles.

Sensors

I did not include the sensors in my sketch but you may use a Touch Sensor on each side for detecting when your robot has bump into a pole, or you may use an Ultrasonic Sensor if you want a non-contact option. You may use another Ultrasonic sensor for detecting when your robot has reach the top, or you can use light sensors to detect the different sections on the poles but remember the colour of wrappings on the poles are random, so you've been warned here. On the way down, you may use a third Touch Sensor to detect when your robot has reached the ground. As for moving from pole A to pole B, no sensors will be required since your robot can only move straight.

If you are daring enough, you may even choose not to use any sensors and rely solely on rotation alone but i wouldn't recommend it unless you are pretty confident with your design.

Programming

the program for this robot should be very straight forward, maybe something like:

  1. move straight until touch sensor 1 bump into pole A
  2. climb pole A until ultrasonic sensor 1 can no longer "see" the pole
  3. climb down until touch sensor 3 hits the ground
  4. whole robot reverse until touch sensor 2 bump into pole B
  5. repeat step 2 & 3.

Please bear in mind that this is just one of the many possible ways of solving the challenge. But my message here is always put your ideas into sketches & drawings using simple shapes and then list down the tasks your robot needs to complete, the constraints/limitations of your design, before you actually build the real thing out. Too often the students tend to dive straight into building the robot without having the big picture and eventually they get stuck very quickly.

So i hope this post helps to give you some idea on how to conquer the vertical limit challenge & also how to tackle a complicated problem in a simple way - put your ideas on paper first (^_^)

13 comments:

Unknown said...
This comment has been removed by the author.
Unknown said...

So, do u think one motor is strong enough to bring the robot up???

Keano said...

With enough gear reduction, yes. But of course you have to experiment with different gear ratios until you get the right balance between speed & power.

Unknown said...

i dont think so,, as u have to bring up the heavy NXT and motors.. have u tried? i think it's not as easy as in your concept..

Keano said...

well if you think one is not enough try to put two then. But you will be left with only one motor to do the rest of the stuff, including moving your robot from pole to pole, attaching/detaching your robot from the pole, & retrieving the ping pong ball.

But if you insist on using two motors to lift your robot up the pole, it is still possible despite incredibly difficult. If you use one motor to allow your robot travel from pole A to B, then it means your robot has no turning ability; 2 more motors for climbing, which means you will have to design a symmetrical mechanism that automatically grabs on to the poles on both sides the moment the robot bangs onto the pole, which is even more difficult to build if not impossible...

So i guess to best way to know whether something works is to try it out and let the results speak for themselves, do you agree ?

Unknown said...

@Julianus

Well If you think the your NXT si heavy just make sure you equip it with NXT rechargeable battery, for my understanding is more lighter then AA. ^^ . Any way ty so much for the tips

hafiz antlia said...

is it,the brick move up also?

Isaac said...

With only the top view of the desjgn, i am not be able to design the robot to climb on a pole. Can you provide some more description and picture of the designed robot?

Gerald Vaughn said...

How do the robot climb the pole while supporting the weight

Anonymous said...

Could you plz put up some more pics of the actual robot? It would be helpful if you could put it up as soon as possible.

Tan Jia Huei aka Sniper Grenade said...

1. There are no structure/mechanism to hold the robot onto the pole, robot will fall off once it started climbing
2.The poles are covered with rubber, making holding mechanism hard to make as it generates friction
3. The NXT is lied horizontally out, it adds more weight to the motor
3 problems which leaves me ^&%&^%&^%

Tan Jia Huei aka Sniper Grenade said...
This comment has been removed by the author.
Agrim Singh said...

hi man

i find your blog to be very useful. could you explain more about the program overall and the design? much appreciated :)