Monster 6WD

We are currently prototyping a new 6WD platform and we also have a cool robot arm kit, both are made of aluminium. I have decided to merge the two into a cool 6WD all terrain robot. The serial interface that comes with the robot arm can control 32 servos leaving most of my MCU pins free to deal with sensors and other motors.

At the moment the 6WD chassis needs better suspension and I am building a new arm, the same colour as the wheels. I am going to use a Picaxe 28X2 for the brain as I am learning how to use this chip at the moment. I will use a SplatBot X2 PCB as it has most of the circuitry I need built in.

The end result will be....

One problem to be overcome with the 6WD is the suspension. When I first built the 6WD it took a lot of searching to find suitable springs. The new chassis is bigger and heavier so we are starting from scratch. This was the original system

I had wanted to use ball joints instead of the rubber grommets and screws but the ball joints available dont seem strong enough and are hard to fit so we decided to stick with the original system but bigger springs.

We started out making them by hand from a length of 2mm diameter wire.

 The problem with this design has always been that the metal is over stressed at the corners and tends not to spring back properly when under a heavy load. So I changed the design to eliminate the sharp corners.

This works much better but 2 turns was too soft. Gao went to the local factory to experiment with different wire sizes, turn diameters and number of turns. We now have 1.5 turns of a different wire on the prototype.

This is still a work in progress. Although we are using 25mm conduit in the prototype the final version will have specially molded motor housings.

I've now rebuilt the Arm using red anodized aluminium parts as it matches the colour of the wheels better.

 Here are some photos showing how everything fits under the deck so far. Click on them for a larger image.

There are 2x 7.2V 4500mAH between the wheels and even with the servo controller and 28X2 processor board there is still room for more circuits.

Looking under the deck you can see there is plenty of room for wires, circuitry and even the odd servo.