How to Design a Sumo Attachment
3D printed extensions such as scoops and ploughs make an excellent addition to Rovers in a sumo battle. It is also a good introduction to Computer-Aided Design (CAD) and 3D printing.
This activity will explore how to design extensions that attach to the rover bolt clip adapter. The clip adapter can be purchased from the Micromelon store, or the files can be downloaded from either Printables or Thingiverse.
For an introduction to sumo, check out our sumo activity guide.
Exercise Setup
You will need 2x M3 bolts to attach extensions to the rover. You will also need a Rover Bolt Clip Adapter. It would be best to have a piece of paper and a pen on hand, which will be used to sketch out initial designs before transferring them into CAD. A computer with CAD software installed is also required. TinkerCad, Onshape and Autodesk Fusion 360 are excellent options with free versions available. Being familiar with CAD before this activity would be beneficial but is optional.
Here’s Our Approach
Stage 1
Designing your extensions on paper is important before transferring them into CAD. Start off by drawing some rough sketches of your ideas. Once you have done that, choose a few of your favourite drawings and draw the side profiles for each.
The side view will be the most important as this will form the basis of the CAD model. Remember to add holes where bolts can pass through and connect to the bolt clip adapter. You will also need to consider a cut-out for the ultrasonic sensor on the front face of your attachment.
Example of side profiles of a sumo attachment
Stage 2
Dimensions for the example attachment
Once you are happy with your sketch, you should transfer your design into CAD. Ensure that you dimension your part accordingly. Note that the dimensions of your 3D printed piece will differ slightly from the CAD due to 3D printing inaccuracies.
The dimensions for the example sumo ramp scoop used in this exercise may be helpful when designing the portion of the attachment, which will connect to the robot bolt clip adapter.
Stage 3
Once you have 3D printed your extension, try and see if it fits on the rover bolt clip adapter. It may not fit perfectly first go, so correcting any issues may take a few redesigns. You can also try experimenting with different print infills to see what this does to the strength and rigidity of the part.
