Heavy Metal

Jay Kickliter

Here's a few photos of my first robot chassis. I wanted to make it out of Aluminum, but I don't have a TIG welder, just a MIG. So, I went to the store and found some 16 ga. 1/2" box section mild-steel tubing. I dont have a scale, the chassis isn't as heavy as you'd expect, but add the gearmotors and the 12 V, 7 amp-hour lead-acid battery and the thing is pretty massive.

Now, I'm going to ressurect the code from a faild balancing robot I made a couple years ago and adapt it to this chassis. My only worry is the signifigant backlash in the gearmotors. But on the plus side, I attached the battery directly to the motors and they are so torquey and fast it is able to recover from very signifigant tilt.

You can find more photos here.

erco

Good start, but your backlash will definitely come back to bite you in a balancing bot. Hard to compensate for that deadband in software, and mechanically, it will probably get worse in a hurry from all the extra overshoot & reversing. I'd recommend fixing that backlash first.

Jay Kickliter

erco, I suspect they might not even work. To be fair the guy at BaneBots told me there was a little backlash when I ordered them, I just failed to conceptualize how much travel a degree of play makes at wheels that large. I wanted to go direct drive, but the battlebots sites where I was shopping for motors don't have much information on running their motors without gearing. I guess they're all about full speed and gearing. Also, I have the problem of all that weight. I imagine most motors, even with at 1/2" shaft, wont like supporting 20+ lbs. The great thing about steel is that if I do need to change motors, I can alway cut the lower unit off and weld on new mounts.