Let's Make Robots!

The Climber - Third ride - It works!!!!!

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Prettybird's picture

Unusual but who cares. Necessity is the mother of invention. Do you see steering with some sensors in the future. It would be great to bring me a beer downstairs.

Thanks, i was in holiday so i couldt se about it did work ;)
dannytemmerman's picture

Why do you have blue paper and tape on the upper stair?

Is it for another project you are working on?

ArunioSmo's picture
This is only protection.  It is painted :)

I think i found a solution, its really comes in a game where you need to go over obstergoals, and then i juse that tactic, but to the subtjek. http://img208.imageshack.us/img208/9208/60319307.png There you see the front, that it does is when it hit the first wheel then it will lift up, but you need some thing to hold it, but you need lots of power. Then i put that arrow to see that when the secound wheel hit then you got exstra power....

 

Hope THIS helps :)

ArunioSmo's picture

It works.

I must still nice edit.

ArunioSmo's picture
This is a good idea. I must try it. :)
emuller's picture

Traction is absolutely the problem.

If you don't have stickier rubber wheels, how about adding some rubber belt tracks? Having said that, you need enough weight to make the rubber belts effective, but if you must add weight, add it only to the centre of mass, not to one end or the other...

 

OddBot's picture

I think this is a very nice design but your problem is not weight or power but traction, you need more wheels.

here is a video of a similar robot that has overcome the problem with more wheels:
http://www.youtube.com/watch?v=mW4LJW6j05E&feature=channel_page

Gareth's picture

For the first couple of seconds just make the back wheels a little bit faster than the front.

(or the other way not quite sure of my logic)

The wheels appear to have enough traction - maybe it just needs more "Push behind" than "Pull infront" for the first part or visaversa.

once its underway (maybe by tilt switch) it can revert to same speed back and front.........

ArunioSmo's picture
This is good but how can I do that? I can not change the speed. These are digit servos. I can only servo position change.
 
init:
servo 4,75 ‘ initialise servo
main:
servopos 4,75 ‘ move servo to one end
pause 2000 ‘ wait 2 seconds
servopos 4,225 ‘ move servo to other end
pause 2000 ‘ wait 2 seconds
goto main ‘ loop back to start

You should set more weight on the backend.... i think.

 

Then the front end should be leighter than the front end and the will push it up at the first step :)

Hope it helps...

PeterJacob's picture

no, that would totally stop it at the last step!

it need more weight on the middle!

AND as you said, the wheel need to be lighter!

ArunioSmo's picture
you 're right. I have to invent something else.
slick's picture
get motors with more torque that way you have more power to deal the the whole gravity thing
ArunioSmo's picture
The servos are already strongly 12kg/cm.
robologist's picture
Add another servo in the middle that has a weight on the end of a stick The servo shifts the weight back and forth according to the orientation of the robot, need an accel or tilt sensor to read orientation.
ArunioSmo's picture
you 're right. I have to invent something else.
emuller's picture

So the problem with the first and last stairs have to do with the weight distribution, I think.

during mid-flight, (i.e. flight of stairs...um. another bad pun..), the rear wheels are taking about 70% of the weight (square root of 2, assuming that the robot is at 45 degrees!), rather than half of the weight. In the case of the last step,  the downward weight vector on the front wheel is much smaller than it is while it's climbing, i.e. it's not pulling "up" as strongly, so has relatively smaller traction.

So you need to either have some way to dynamically change the weight distribution, which would make it more complex, or you could try using "stickier" rubber on the wheels - that would increase the normal forces that are the traction.

There's an important point here, in response to one of your comments - adding rubber spikes to the wheels actually DECREASES your traction, this is because by using spikes, you decrease the amount of contact between the wheel and the ground. If you want maximum traction, you need very smooth, sticky rubber - this is exactly why formula 1 race cars have "slicks", which provide maximum traction with the ground.

Great idea. Have you tried more traction to get over the first stair?
mikv's picture

I can imagine that as 1 foot(toes not inches) of a full standing robot walking up stairs with the ankle above the controller board,

don't ask me how it could balance but it would look awsome if it could work.

 

 

mintvelt's picture
Very cool. I love the simplicity. 
Super simple! It should be a manual for beginners.
emuller's picture

awsome!!!

Love it. Great and simple. 

 

what's the next step (pun intended)?

robologist's picture
That is amazing, very cool idea! Pretty fascinating to watch it work!
ArunioSmo's picture

Hi!

And now, I will show you the first ride (without sensors)
isotope's picture
Interesting. Do you have any video yet?
ArunioSmo's picture
Not yet. I am still waiting for my servos (4 x Tower Pro Servo MG946R with Stall torque 12kg/cm).
PeterJacob's picture
climb stairs.. ?
ArunioSmo's picture

One prototype was already finished, but i have two problems:

- first and last stair 

I think the first and the last in everything you do is the hardest.Anyways I guess some stairlifts are more practical , easier and attractive.
PeterJacob's picture

now i have seen the video i think i know how to fix that.

try to add some weight just below the micro-controller, and maybe add some small high-friction rubber spikes on the wheels

ArunioSmo's picture
Unfortunately does not work :(
PeterJacob's picture

TRY! to put the wheels a little off-center on the servos

that would make a low-(but still a little)bumby ride and maybe work!? :D

(would look funny if too off-center)