- Try to pull a heavy object for a given time or distance
- RC with driving aid (Hybrid)
- Maby long range with a trailer (extra battery’s)
- Maby some other ideas I get from you…
About the first video: This is the first autonomous pull it ever did! It did pretty well, not as good as manual RC but above expectations. I tried to simulate a pull in the code. Start with a little bit of power to tention everything, Build up the power till it starts to roll, floor it and go!
The video also demonstrates whats wrong; the nose jumps a lot. Looks cool but doesnt go anywhere. Thats why you need traction control and some tilt sensing technique. Traction above raw power.
And how will it do that?
- With encoders at the back wheels
- An arduino
- A 20A RC speed controller
- Ordinary traction control
- Some things i havent figured out yet such as, line following sensors, an internal amp meter to measure power, distance measuring sensors and tilt sensors
- With help, A self learning traction system.
- Maybe some other techniques I get from you…
What works right now:
Servo steering
BEC Power from the speed controller for the arduino and servo. Only 1 battery needed and no extra circuitry!
Potentiometer Driving(running behind it turning knobs…)
What problems occured:
- the battery is flat after just one pull like in the video! Maybe because the battery is old, maybe because of the amps drawn when it is almost stalling…
pull things with intelligent traction control
Actuators / output devices: steering servo, 12v motor with differential
Control method: autonoumous, semi autonomous, rc hybrid
Sounds like an interesting Sounds like an interesting project, but I’m going to have to gently point you in the direction of the rules, which state that you shouldn’t post a robot project until at least some hardware has been assembled, and preferably a photo or two has been taken of said progress. The best thing to do until you get to that stage is to edit this robot page, and tick the ‘draft’ button at the bottom. When draft mode is activated you can continue to edit this project page without it coming up on the LMR frontpage, and thus avoiding the wrath of any of the proper mods (not really wrath as such, that’s reserved for people who write in txt/leet). When you’ve got some pretty photos for us, or even better some video, you can ‘undraft’ the page and let your new robot make a solid first impression =) In the mean time, the blog you’ve already started is a good place for people to comment on your ideas and concepts thus far.
That clears up the Tonka That clears up the Tonka, but not your Avatar. What is it? A Horizantel Owl with Rabies? Or maybe an Owl with Rabies in a Hotel?
The rubber is rather hard. Very like those old style lego tires. The newer ones are much softer. The traction on heavy clay(what we have around here) is about the same as on a wooden floor due to the profile of the tires.
I already did… And i won! It was a bit unfair, because my opponents were lego and knex pullers. The lego one had 4wd and a compressed air turbine, but it trashed all its gears and melt itself…
So now i am making it even better! looking to make a challenge one day against an nxt bot to test manoeuvrability, pulling power and intelligence.
You may ask yourself What is powering that thing!? Well its a heavily geared down(don’t how much) Mabuchi RC-280SA brushed motor. Sold for powering rc toys, hair clippers and Vibrators… It outputs 24 watt at max. There are 6 subtypes of this motor with different voltages. but i can’t read which one! So i dont know if i can take it to 9.6 or 12 volt. Help me out! How fast could i damage it?
Cool idea, a truck pulling Cool idea, a truck pulling robot. I’ve never seen this before. This could be an idea for some new robot challenges: ‘Truck pulling’ or ‘Tug of War’ for robots.
I suggest encoders on teh FRONT wheel rather than the rear. I realise you have the problem of the front wheels lifting, but you really need a “slave” or “jockey” wheel in order to do traction control: you need to know if the vehicle is moving. If you put the encoders on the back, you won’t know if the wheels are spinning.
One possibility is an encoder on the end of a shaft which can drop with gravity. That way you alwasy have this slave wheel onteh ground tellig you if you’re moving.
My kids have this exact tractor and one trick I did to enhance teh traction was a coat of liquid latex on the wheels. It doesn’t last very long because it picks up dust and stuff, but one quick wipe with warm soapy water and the “tyres” are as sticky as ever!!
Did the video look like a final test? It wasn’t meant to. It is just a quick test to test nothing will burn out and if the hardware is fine under stress.
Why not just add some weight to the front end? because it is more about power to weight ratio than to what it can pull. And I want to see just how much of an improvement it is if the power is regulated in a smart way.
Thanks for the feedback. I could find a lot on the internet about what traction control does, but not how it works.(I didn’t search very long) I was planning to reinvent the wheel and this will give a head start. I am thinking about putting encoders on all the wheels now. isn’t very much extra work, but it may come handy later on(information about cornering/drift) The final test will be outside on slippery surfaces, so the latex doesn’t seem nessasery.
thanks for your support!
Edit: I just realized why i wanted the encoders on the back, I read an article about an electronic limited slip diff type of traction control…
You know what would improve traction but add very little complexity or weight? A wheelie bar.
You could spring-load it and use a mechanical limiter to keep all 4 wheels on the ground, or failing that at least keep the back 2 on the ground with good force.
