Duh

So I do get to work on my machine skills - cut one of the wheels too deep. Bonus is finished wheel is now down to 2.66 ounces. Lighter is better right. Never knew dumb could actually work out.

Am trying to figure out the suspension right now. Probably going to use RC off road shock absorbers and some sort of unequal length heim jointed rods. Sounds good in my head. Also really trying to narrow down my motor choices. Probably brushed gear heads for now. Guess I gotta finish the platform, calculate weight and figure out what size I need.

Remember, as I have learned. With motors, its the stall current that matters since a locked up motor could fry a bunch. Some small motors that draw less than 1/2 amp can easily exceed 5 amps at stall. And also remember that a motor that isnt moving must quickly go through stall therefore there is a momentary current draw spike at the stall current. Four motors like that would be 20 amps total!

3D Modeling

So for those of you who have used or have access to a 3D modeling suite like Autodesk Inventor, you are probably aware of the capabilities of this software. For those of you who dont, here is a little example. The wheel I created out of 6061 aluminum weighed 2.71 ounces. Inventor says it should weigh 2.704 ounces. Really amazing. Guess I need to work on my machining skills!

Let there be wheels

So any project presents the dilemma, buy or make... Well I look at making as kinda the fun part and really labor costs are the worst in any project and relative to the rest of the world, my labor is cheap.

So now there is a real prototype wheel for the as yet unnamed robot. Several hours slaving over a benchtop lathe and voila. The specifics so far are as such. Extruded billet started around 9 ounces. The mid point was down to 7.5 and the final form, speed holes and all, was a scant 2.71 ounces. Could always be lighter but this is pretty good. With the Traxxas tire the unit weight is 3.96 ounces which will make the full set right at a pound.

The next model might have something better but this will work for now. Keep it light keep it simple right?

Wthere the rubber meets the road

So for anyone aspiring to build a robot the question of tracked vs wheeled comes up. Well for my purposes the wheeled idea won out. I hope to have independent drive motors, and control, for each wheel eliminating the need for transmissions or differentials.

Now, that said, I thought I would start in in the R/C car world and man... There are a TON of tires and wheels available. I ended up hitting the local shop and with their help I found a Traxxas Anaconda 2.2 inch tire that will suit my needs, for now. The R/C tires use foam inserts for support, come in all varieties and sizes. There are also wheels ranging from cheap plastic to CNC bead lock varieties that will set you back a ton (100+ bucks!)

Being a real adventurer I am going to make my own aluminum wheels with the help of a cheap, benchtop lathe. More on that process as it evolves.

For now I will post the drawings of the 3D wheel model, both as it will be made and the 'cool' version that I dont have the machinery for. Both are intended to help anyone that wants to follow along on their own.

The Beginning

So I have decided to document publicly my attempt to build a robot. I hope it will be a good learning experience for me and for anyone that chooses to read this.

A little background. I am a CS student at the University of New Mexico and hope to use this as a platform for autonomous control and machine development.

The specs, as I have them in my head, so far are.

Controller - Arduino Uno (a great, low cost, open-source hardware processor)

Chassis - four wheeled with independent drive motors on each wheel. Platform will be a flat plate that will carry electronics and sensors.

Power - proof of concept will probably be corded power supply that will migrate to batteries and hopefully solar charging.

Wish list - I hope to add wireless programming, onboard SD card, GPS and some sort of display for diagnostics.

As yet the design is in the early stages of 3D modeling with Autodesk Inventor and as I develop more ideas I will post them here.