Robotics Education & Competition Foundation
Online Challenges

Improved 4 inch Omni Wheel. 8757C

1

HouseofScience
Entry ID #: 4551
Created: Sat, Jan 6, 2018 9:13 PM


Why we designed it The Improved 4 Inch omni wheel improved design I have modelled in Autodesk Inventor Professional 2018 was created to improve the functionality of drive trains. We noticed there is a slight amount of slop between wheels, sprockets and gears on normal sized axles which added with other slop causes results in a large collective slop throughout a drive. This project was set out to help minimise a part of this collective slop and provide more options on a driven wheel. How it would be used This omni wheel allows for drive trains to have less slop between the sprocket/gear and the wheel but directly attaching them together. This means a more responsive drive that will give an edge in controlling the robot. This also allows a driven wheel and sprocket/gear to be on a screw rather than an axle which means you won’t have trouble with an axle bending from the force pushing or bending from weight/load. This also allows better load sharing between the sprocket and the gear on the axle spreading out the distance of the load lowering the likelihood of twisting the axle. We would use this design on our drive in our existing robot to strengthen our front wheels with a screw rather than an axle for extra support and decreasing the slop between our sprockets and wheels. How it was Made: This part was made in Autodesk Inventor Professional 2018 64 Bit edition Build:112 I imported the STEP file of the 4-inch Omni wheel from the Vex website to use as a base for my Omni wheel. Using a Vex 30 tooth high strength sprocket as a reference and official measurements I created a disc with the sketch tool, extruding the round circle and using the hole tool to “drill” out the holes at the correct spots. I left a round circular hole in the centre with a diameter equal to the maximum width of a high strength axle as I planned to use the centre of the omni wheel with its space for inserts. Next using a dodecagon (12-sided polygon) sketch on both sides of the omni wheel I extruded to remove the existing spokes to make room for the plate. I used another omni wheel model to cut out the centre with a donut shaped sketch and more extruding. The reason I used a separate wheel’s centre rather than keeping the one from the main wheel I am already using is, so I could do extra touch ups and keep it individually editable from the main wheel. Now I inserted the disc I had previously created and positioned every part into the wheel. I made the Rollers into a single part, so I could move the whole set of them at a time to make repositioning easier. Finally, I added some fillets to round off some of the edges in the wheel and make the wheel more aesthetically pleasing. Conclusion From this project I learnt about how to CAD basic structures and modify existing structures. I gained a basic understanding into how to use Fusion 360 (which I initially started using) and Inventor Professional 2018. I plan to use 3D design software to produce robot systems to see whether they will meet the requirements I envision and fit within the allotted space I have. This will mean my team can get robot designs designed in a way without the need to construct them without any physical construction meaning if the design does not meet our requirements we do not have to disassemble a robot and the parts will not have been cut to size. Having these skills develop through projects such as these I may find it will open extra options into career paths and options as many employers now look for people with experience with 3D design. It will certainly be of help in the engineering course I plan to take when I leave school. I thank Autodesk for sponsoring this challenge that has sparked my interest in 3D designing. -Jacob Church 8757C

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