Im finally getting some spare time now and have started my robot project. First I need to actually build the thing. Right now im just doing mockup and cutting some parts. Its bascially just going to be a front wheel drive, rear steering ground rover, with full independant suspension, 2x 6cell NiMH packs in parallel, 540 motor driven bot. All being controlled first by a HC11 chip AKA handyboard1. After I get tired of that I will probably step up to the BASIC Atom.
First mission is just to get something working. After that im going to do simple obstacle avoidance probably with ultrasonic sensors. After that probably add a magnometer and do a little dead recon. Then if all that is a success, by spring semester I will have GPS with a wireless connection to a PDA via 802.11b with simple waypoint navigation. Probably with a PDC-10 or what ever I can find simple that works. This is my first “real” robot…uh robot. I have built lego mindstorms ones before and the kit ones you can buy but nothing like this. So if anyone has any good pointers, especially when it comes to navigation, please dont hesitate to share your knowledge.
Do you find that driving fast RC cars in reverse is a bit tricky?
Because, with the drive wheels in the front, and the turning in the back, driving in reverse is practically what you’re doing.
I find that reverse setups make it really easy to oversteer at high speeds.
Do you not have those problems, or did you find a way to overcome them?
yes I found a way, drive slower. I plan on using a simple Mabuchi 540 32T single wind motor. Ill probably gear the tranny down to about a 6:1 ratio as well so top speed will probably only be about 5mph. I made it rear wheel steering so it could manuver better in tight areas. Otherwise it would have about a 2ft turning radius.
I’m probably just going to go to my hardware store and buy used chordless drills.
That way, I’ll have a moderately light and pretty powerfull motor and gearbox assembly, as well as batteries.
Plus, the continual ability to adjust the gear ratios is always nice.
It’ll probably be a bit expensive, though.
For decent torque I’ve been using Integy Matrix Pro 55T lathe motors.I have 2 of them pushing my 4wd/4ws rover(will climb a wall) figuratively speaking as I have yet to figure out that whole anti-gravity thing… They go for about 20 bucks at Tower Hobbies.
Iv used very high turn motors in my old TXT-1 rock crawler that I used to have and they moved it very well. My favorite set ups are very high turn motors with a lot of voltage. It always seems to work better then low turn motors with less voltage. I thought about using something like that for this bot but Im going to first try a 19t double just because I have it laying around.
