Small robot platform

a small platform with wheels that can be used to mount a variety of sensors. the front wheels have independent axes so the silicon wheels won't get damaged as easily by friction. i modeled wheels very closely to the pololu wheels of the same size, which are the ones i will use in the real platform. Edit: the online 3d viewer shows the bearing holder wrong, i attached a picture of how it really looks in the step, sat and iges files. Edit: new bearing holder added. since in the real model i noticed some instability on the front wheels, i decided to add 2 bearings that roll against the platform. i also added a hole to be able to screw the bearing holder to the servo instead of using glue.