I’m working on this tankbot: Powerful Vex Robot Carries Dog - YouTube
It consists of 4 motors, geared down, connected to two large sets of tank treads. Together, the treads stretch longer than me. They are made up of two tread kits. The treads have 8 rollers, and 6 of those gear thingies (forgot what they’re called LOL).
I used quite a lot of metal, so the design is VERY sturdy. It can support my full weight. When it wasn’t so bulky and heavy, it was able to drive around with me on top. (I weigh 100 lbs) The design is supposed to allow room for cargo while staying strong and rigid.
The front of the bot is tapered to it has a wedge of tread to help it climb objects. It can climb bricks, wood, dirt, hills, rock, etc. Plus the extra metal in the front tapered part helps tilt the robot forward when it climbs an obstacle.
It consists of 4 motors, geared down, connected to two large sets of tank treads. Together, the treads stretch longer than me. They are made up of two tread kits. The treads have 8 rollers, and 6 of those gear thingies (forgot what they’re called LOL).
Have you thought about adding additional Motors, controlled with the Power Expander or a second Vex Controller. You could decrease the Gearing Ratio, and get more speed…
Thanks! I was actually thinking about getting some of those expensive (but worth it) high-strength motors and leaving the gear ratios alone. I really want to see what this thing can carry! I might also add a turret or something with another mcu.
And since I can’t afford many of those motors, maybe I could total 8 motors,bilk you said? Each drive roller could have two motors instead of one. Twice the awesome vex power!
You need to support the axle going into the encoder better.
You should think of the encoder as a wheel that will make contact with the floor and it should be supported as such. You should support the disc with at least two bearings per shaft hard mounted to the frame. Ideally a bearing on both sides of the encoder disc. Also, you should not try and support one of the axles with a metal part without a bearing. You should also not allow any part of the metal axle/collar to touch metal directly. Use a plastic washer or spacer to prevent this. Last, if you are going to run a chain or gear the encoder you should think about gearing it up, that will give you better resolution (try and keep it around 800rpm). FYI the Vex motors spin at 100rpm ish.
It looks to me like the shaft may be supported by two bearings the obvious one on the left and it looks like it could be supported by a piece of angle just to the left of the encoder as well. I could be wrong but it does look that way to me. Ideally you would avoid a cantilever but the encoder is basically no load.
You want to try to relieve all possible stress from the encoder disk if possible because the disk has a tendency to shift a bit inside the casing which could give odd values or damage the encoder.
Thanks for all the info! The axle is actually supported by the angled piece and it has round holes, FYI. I probably should add a couple of washers and I’ll gear it up! I think I got the axle pretty centered in the encoder. That was the tricky part. LOL there is actually only one bearing. The one on the metal piece sticking upwards. I found no need (or room) to add a bearing on the angle.
