44mm Mecanum Wheel (Small, Solid and Low Cost)

thingiverse

These are Mecanum wheels designed for small factor robotic systems. It's a low-cost design, the only non-printed parts required is some dressmaker pins. Testing video: https://www.youtube.com/watch?v=WKruDl5lpHE. Specifications: Wheel Diameter: 44mm; Wheel Width: 21.4mm; Axle Diameter: 3mm; Accessory Parts: 27mm dressmaker pins. UPDATE - 2016/04/12. Some ask for more about the rover so I uploaded the basic parts I used to build the rover in the video. Please read the last section How to Build a Rover. Print Settings: Printer Brand: Up!; Printer: Up Mini; Rafts: Doesn't Matter; Supports: No; Resolution: 0.2mm; Infill: 0%; Notes: This model is easy to print for most printers, as long as you follow these instructions: Print with NO SUPPORTS. This is important because this model is designed as a self-supporting shell structure. Adding supports will not give better results but ruin the surface. Print also with NO FILLS. The model has a closed shell which is strong enough for any platform at this size. Post-Printing: How to Assemble: Put a roller into a slot on the wheel body, and push an dressmaker pin through to mount them together. BE VERY CAREFUL when working with those pins. You will need some practice before you can install a roller without bending the pin or hurting your fingers. Based on your printer's resolution, the mounting holes might be too small. If that happens, rework the holes with a drill. Make sure that the rollers can roll smoothly. 27mm Dressmaker Pins: How to Improve Performance: The performance of a Mecanum wheel depends heavily on the grip between rollers and ground. Print the rollers with finest resolution will improve it. Also, I found it helpful to cover the rollers with a piece of heat shrink tube. I tested it with 12mm heat shrink tube and it improves a lot, as shown in the video. Heat Shrink Tube can improve grip: How to Build a Rover: This design is about wheels, not about rover. The rover in the demo video was far from satisfactory. It only served as a testbench for the wheels. But if you would like to build a similar one, here is some advice: BOM: Printable: Top plate x1; Bottom plate x1; Mecanum wheel x4; Motor mount x4 Non-printable: N20 Gear Box Motor x4; L9110S Dual Motor Driver x2; Logeek Max10 Dev Board x1; ESP8266 Wifi Module x1; 2S Li-ion battery x1; and several Hex Rod Coupling Nuts & Screws. About Motors: Some will prefer servos instead of DC motor, like this one by @Madox. If you want a serious work, you should read his instructions instead of mine. I choose 100RPM N20 Motor because it's smaller and faster. However it might be tricky to handle speed differences between motors. About Electronics: As a FPGA engineer, I use Logeek Max10 which is a FPGA dev board, and my program is written in verilog instead of C code. That is why I suggest you look into other designs for algorithms. If you use Arduino UNO, there is a problem that L9110S requires two PWMs per motor, that gives eight PWMs in total. Since UNO does not have that many PWMs, I guess you have to hand code GPIO to emulate PWMs. For Arduino Mega or newer models, it is not a problem since they have enough PWMs. About RC: I use a ESP8266 WiFi module and a client App on Android for remote controller. In fact it is my colleague's work and I borrowed it. There should be a lot of reference designs for ESP8266. There is a simple principle for mecanum controller. To get full control on mecanum wheels, at least three control channels required. One for overall throttle, one for left/right differential, and another for front/back differential. The speed of each wheel is a sum of the three signed components. I truly hope this will help, but what you will get largely depends on what you already have on your hand. This why we call it DIY. Have fun! N20 Gear Box Motor Logeek MAX 10 Dev-Board