Large Mecanum Wheels

thingiverse

Human: 90mm (diameter) x 22mm (width) Mecanum wheels, used by our "Tigerbot" in PiWars 2018, measure 90mm in diameter and 22mm in width.\r\n\r\nPiWars sets a maximum width limit of 225mm for participating robots. The motor/encoder/gearboxes (Pololu 25mm gearmotors) took up most of the available space, leaving little room to spare. Commercially available mecanum wheels were too wide and expensive, so we had to design our own.\r\n\r\nThe rollers were printed in RigidInk TPU using a vertical printing technique with a brim and sequential printing option to minimize stringing between the rollers. We left plenty of space between each roller for the print head to move freely - 16 at a time on my Prusa print bed was the maximum.\r\n\r\nThe frames were printed in simple PLA material. Two halves bolt together using M3 nuts/bolts, providing a sturdy base for mounting the wheels. Three bolt holes are provided for attaching the wheels to a 25mm cylindrical hub (not included), which is secured to the motor with a grub screw. The rollers attach to the frames using 26mm dressmaker's pins, held in place with a dab of epoxy on each head - make sure the roller rolls freely before applying adhesive.\r\n\r\nFor a four-wheeled robot, you'll need two sets of wheels: one pair of clockwise wheels and another pair of anti-clockwise wheels. Mount them diagonally opposite to create a stable platform.