I am working on my first robot, I have dubbed him (Ralph)red, he is to eventually be part butler part dog. However I have run into a issue. I have a tire that slips when on the floor. It doesn't always do it, but sometimes it just spins. The kit I got the motors from is here. (Radio Shack closeout) I am using the lowest geared motors for the time being. He has managed to drive over extension chords and transfer from Linolum over a protective strip to carpet. He is upside down in the pic below, I was attaching the sensor brackets. Right over the motors in the center he has a motor controller, A little further back arduino mega, and just behind that (Touching on their edges) is a small bread board. Over the "Drivers side" tire is a 4 AA battery pack (for the motors), and the "Passenger side" there are three 18650 battery's with a buck converter. There is a ball caster on the back. So my question is, do I need more weight up by the motors? I could add some... I built the chassis from a erector set and there is a small tray there.
EDIT: Thought I should add it's usually the passenger wheel (Under the 18650s)
I assume you are doing a Mr Scotty "Giving it all she’s got Captain!"
Try to ramp up to the speed you want. do the speed setting in 25% increments. See if this helps any. You could try and redistribute the weight as you stated. For a quick test to could do two motor writes, one at half the speed you want then delay for say half a second and then a write to the motor the full power you want.
I will say, that these motors and wheels are nice and cheap, but are not perfect. They do get your bot going though.
If the robot weights more then 2 kg the motors may be strained or stall on small obstacles. If the wheels slip add some rubber bands and make sure the wheight center is near the wheels.
I apologize. By slipping I mean that the tire isn’t getting any traction, wheel spins but acts like it isn’t touching the floor. It crawls at a nice pace with the 220:1 gears, including over extension chords with ease. (in house that will probably be it’s largest obstacle). I will look at the motor link in a bit, I am using my phone at the moment.
Ok, so at the suggestion of my friend I checked the height of the board to the frame… and all the bolts I thought I had at the same height… one of them was a quarter inch off. Readjusted using a ruler and no more wheel lift. Hooray!
I am looking at cutting down the board some this weekend to reduce weight. I am also debating moving the batteries to the tray the motors are mounted to… If I can sourace a descent DPST (Or DPDT) Micro switch.
I also checked the little motors for heat (As best I could with the gear box there). It looks like they are running about 4-5F warmer than room temperature. Is that about normal?
I wouldn’t think that a 5 I wouldn’t think that a 5 degree above room temp is bad. I’m just surprised that they work at all, pushing that mass!
I now have a bunch of motors, including about four sets of the yellow motors. I also like the Dagu encoders that work with these motors. I have to find or find a good way to make quadrature encoders.
