2. Wheel Mounting

Wheel and Sensor Mounting

 

The frame is designed to be experimental. Nothing is permanent and can be moved where needed. The wheels are about the only important part that cannot be moved. As I mentioned earlier I mounted the servos in Aluminum U channel. However servos don't get you very far without wheels. I found a tutorial on mounting the omniwheels to the servos here: http://www.acroname.com/robotics/info/ideas/omnimod/omni_mod.html

 

However I didn't like the design so I modified it slightly. I didn't use the finishing washer. I just used a standard locking washer. Also I tried the nylon bolts but found them lacking in stability and strength so I upgraded them to steel bolts. These work great and have not failed me yet.

 

From ExMod

This small metal connector can be found at your local hardware store. Its called a T-nut. They work great. I bought this one at Lowes.

From ExMod

A big issue was finding a round servo horn. I finally had to break down and buy a bag of miscellaneous servo horns from two different hobby stores in two different states. Hobbytown USA sells them but I couldn't find them for much cheaper individually online. This way I have a few extra horn types for other projects.

 

The small metal peice is called a T-nut. They can be found at hardware stores. I purchased these ones at Lowes. They work great.

From ExMod
From ExMod
From ExMod
From ExMod

The servo horn screw didn't fit through the T-nut so I had to put it under the T-nut and bolt that down before I screwed it into the servo. A bit of a pain but the added benefit that you can't loose the screws. That was the hard part the rest is done by threading the other T-nut onto the bolt and screwing the bolt into the servo horn's nut. Don't forget the lock washer to keep things tight. Remember the idea is not to tighten it down as tight as possible but to secure the omniwheel to the servo. Watch you don't get over excited and damage your wheels.