This time I will present some photo’s and a video of revision 2 of my rotacaster bot.  I also gave it a name: Sidbot.

There are some small changes to the first model I made. These changes all serve one purpose, I want to be able to control the vertical angle between wheel and surface. This is in preparation of my NeXT project, more on that later.

The top of the platform has been modified, it now has the same triangular shape as the base. This more regular shape gives a better platform to expand and allows for better access to the NXT buttons and screen. The motor frames no longer are fixed to the platform. They are mounted with a hinge to the bottom of the platform, on top they are attached via shock absorbers. The shock absorbers diminish vibrations. But the real reason for this setup is that it allows me to modify the length of the top mount of the motors and thus to change the between wheel and surface.

Here’s some images of the robot and a video of the robot in action.

So, why on earth do I want to change the angle between wheels and surface. Well, I want this robot to be able to balance on a ball and move around. Just as the dog in the video below. For this the rotacaster wheels need to ride the surface of the ball, and this, as we all know, is round and the wheels must be perpendicular to the surface of the ball.