Parametric Mecanum Wheel Generator Tool

thingiverse

This tool creates Mecanum wheels for various sizes and shapes using OpenSCAD. Downloading the three SCAD files is a straightforward way to get started, as it allows changing parameters in the wheel parameters file while watching resulting shapes change in the hub file. It generates roller shapes so that when the wheel spins, the contact surface matches a virtual "three-dimensional wheel" created by rotating a cross-sectional shape around the axle. A presentation explaining this concept is available above. Two objects are generated: a hub shape that holds rollers and fits onto a keyed motor shaft, and the shape of a single wheel spoke roller piece (1/2 of a roller) for a mecanum wheel. The roller pieces are created by taking the intersection of a cylinder defining the possible volume of the roller, and intersecting it with the virtual wheel shape. A slice of this intersection is then rotationally extruded to make the spoke shape. A few geometric features like a bearing spacer and captive nut holder for using a screw as an axle are added or cut into the spoke. This simplistic approach produced great results for the configurations I tried, despite its limitations. Because of the large number of parameters and the relatively tight constraints of mecanum wheels, it takes some tuning to get something that's mechanically workable. However, changing values and watching the entire assembly preview change in hub.scad makes the process not too painful. To make a set of Mecanum Wheels in the sample size provided here, you'll need to print two of each hub shape and 14 roller halves per wheel, for a total of 56 roller halves. These were used to make an All-3d-Printed Mecanum Wheel Rover using Parametric Wheels. For a more complete writeup of the project, BOM, and assembly process, check out this blog post. The most current source code for the SCAD objects, LPC1769 firmware, and PC software to drive it with a game controller are on github. The sample hub and roller included are sized for seven rollers per wheel, and assembly using MR63ZZ bearings and M3 screws. The bearing decision and layout for the sample wheel were inspired by the awesome Mecanum Wheel Rover 2 by Madox. https://youtu.be/EiNMUb7Gtos Print Settings Printer Brand: SeeMeCNC Printer: Rostock MAX Rafts: Doesn't Matter Supports: