When building a mobile robot, one of the easiest ways to allow it to roam about is to use a wheel on either side in a sort of tank-like configuration. An example from Macerobotics is shown in the image above. On the other hand, it’s a good idea to consider other options. Tank treads, Mecanum, and omni-wheels are all viable options.
One clever wheel option, which according to Wikipedia was patented in 1919, is the omni wheel. These devices, which have smaller rollers attached at 90° to the larger wheel’s axis of rotation can be extremely useful because of their ability to move items in two directions. In fact, they can often be seen transporting boxes in factories. Importantly for this discussion though, these wheels can be combined in the angular orientation seen above to allow a robot to slide and turn in any direction.
Another interesting option is Mechanum wheels. Instead of secondary rollers being attached at 90° to the main wheel, they’re attached at 45°. This means that a vehicle can be set up with the wheels in an orientation similar to a traditional car; when all the wheels move forward, the robot also moves forward. The trick comes when the wheels are rotated in different directions, allowing it to turn and slide in a similar manner to how omni wheels work.
So which type of wheel or drive system is the right choice for your next project? Of course it all depends on the situation, but its at least a good idea to keep different options in mind. Grab some more inspiration for you upcoming builds by browsing the Robot and Drone parts on Tindie!