The Tracked Robot Project 2010

Page 2

To begin construction you will need to have the three main components of the robot which form the basis chassis. You will need to have the laser-cut wooden chassis, or you can cut one yourself using the plans and common woodworking tools... or you can come up with your own unique design based loosely on this chassis. The chassis presented here is open source... you may develop it into anything you like... if you publish a project based on it I would like to get credit for the basic design.

Wooden Chassis Parts
parts layout
These are what the parts should look like for the default kit with no modifications.

Tamiya Track and Wheel Set - Part Number TAM70100
Track Set
I purchased this unit from the local Hobbytown store.

Tamiya Twin-Motor Gearbox - Part Number TAM70097 - Front View
Gearmotor - Front
I purchased this unit from the local Hobbytown store.

Let's start with the Twin-Motor Gearbox set. This unit contains two independent motors which will allow us to run each track forward or reverse independent of each other for skid steering. The motor kit can be configured in one of two ways, 58:1 where the motor turns 58 times for every 1 turn of the output shaft, or 203:1 where the motor turns 203 times for every 1 turn of the shaft. It is VERY important that you build the motor set to use the 203:1 setting. You need to do this because of two factors... you will need the extra power this configuration gives you which is 3.5 times more than the 58:1 configuration. It will also turn 3.5 times slower... using the 58:1 configuration would likely mean the robot would be under-powered and could cause damage to the motor unit.

Tamiya Twin-Motor Gearbox - Part Number TAM70097 - Back View
Gearmotor - Back
The configuration on the right is the one you want to assemble.

Additionally... and also very important... the robot chassis was designed to have the shaft of the motor use the center-rear power port. Building the motor in the 58:1 configuration would cause you to use the upper-front or lower-front port... and the motor shaft would not align with the hole in the chassis. (If you did modify the chassis... the tracks would not fit properly and would also need adjusting by relocating the rear hole.)

motor assembled
The assembled motor with capacitors and wires added.

Follow the instructions to assemble the motor carefully as there are many small parts. I recommend that you place everything into a tray or shallow bowl / container so that you don't drop any parts on the floor and loose them. Assembly can be tricky, if you do not get it right take the unit apart and try again... it just takes a bit of patience.

I added small capacitors to the motor to remove some of the power spikes from the supply and to make them run slightly more quiet. The motors come with some silicone grease... but if you wish to add a bit more it probably would not be a bad idea. Avoid oil as petroulium products can cause plastics to dry out and crack over time... be sure to only use silicone grease as lubricant.