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The software for this unusual 3WD robot design is still being developed, but the completed build started with the visualisation images, as shown above, that were produced by FreeCAD when designing the circular 3D printed chassis plate.

It uses so-called omni-wheels that (should!) allow multi-directional movement with appropriate motor direction control as illustrated on the right.

The overall design adopts the basic single-plate chassis design approach used in previous 4WD designs (e.g. see here). It also uses the RPi-flex custom PCB - although this 3D chassis plate design is just focused upon overall system control with a Raspberry Pi 4 (2G memory version used). This limited build scope means that this 3WD robot chassis plate is not intended to have many 'flexible' build options, however the overall build does re-use many of the other 3D print components used previously in the 4WD designs (see here for some more details).

Commercially available omni-wheels were sourced, as shown below, but to use these a pair of custom 3D printed adaptor components are also required per wheel, and these are shown in more detail in the second set of images below.

Also shown immediately below are images of an initial full build that was completed and used for initial bench testing.

As shown below left some 3D printed omni-wheels have also been produced (albeit somewhat time consuming to print and assemble!) and these are a simple push-fit onto the axles of the geared motor drives.

Shown in all the other images below are visualisations of the 3D printed adaptor components needed when using the commercial omni-wheels.

These custom 3D printed wheel adaptors for the commercial omni-wheels use a 30mm M3 pan head screw inserted from the outside, through the hub cap, then through the wheel, and into the inner connector - screwing into a M3 nut inserted into the slot in the inner connector. A 6mm M2 self-tapping screw is then used to 'fix' the overall wheel/adaptor assembly to the axle shaft of a YG2900 geared motor drive used for each of the three wheels.

All the 3D print designs for this 3WD robot build can be downloaded from the Prusa web site here.

The images below show a complete build using the commercial omni-wheels with their adaptors:

This build uses a new updated design for the custom PCB, and the 'gerber files' for the design of this PCB can be downloaded from this GitHub repository - this repository will also make available the software that is being developed for the robot as soon as it is reasonably stable.

 

Wheeled robot projects:

 

 

Robotics projects:

 

All the currently available maker project information: