What do I need?
In order to compete in almost any robotic sport, you will need some way to move around in a controlled manner. Almost all bots in competition today use at least 2 wheels to accomplish this task.
In this section, we will review options for selecting and attaching wheels to your bot. We will also take a look at some alternatives; such as “tank style” tracks (technically a version of wheels) and robotic legs.
Types of wheels
There are literally thousands of different combinations of wheel shapes, designs, and materials. While this can seem overwhelming, below are some general questions to ask yourself and tips as you decide what works best for you.
- How many wheels to I need? (Most bots use either 2 or 4 wheels.)
- Where should I place the wheels? (This will depend heavily on the design of your bot. In general, you want to ensure your wheels are in a place where they can most easily move you around while limiting their exposure to damage during combat. You may want to also plan for getting flipped over or “inverted”.)
- How big should my wheels be? (This will also depend on placement on the design of your bot. Also, consider the weight of your wheels and if an increase in size is worth the increased weight. Lastly, remember there are two main components to your wheel size: Diameter and width. Do you want large thin wheels or short and fat wheels?)
- Do I want to use tank tracks on my wheels? (This is a fascinating design and viable option for many bots. The track will provide additional traction and stability but could add weight and more complexity to your design.
- Do I have to use wheels or tracks at all? (Nope. You can get creative with your design and use legs, shuffers, or any other sort of locomotion. In many cases, you can actually build your robot to a larger size for the competition if you don’t use standard wheels or tracks. (sometime up to 100% bonus!) As long as your bot meets the rules for the competition, you’re good to go.
How to attach wheels to motors
When designing and testing your wheels, it is important to consider how well your wheels move your bot around the arena. One of the biggest factors in this is your wheel’s “traction”.
Traction is the friction between wheels or tires and the ground that allows a vehicle to move forward. It is the resistance to spinning when a torque is applied to the axle the wheel.
Wheels coated in foam, latex, rubber, or silicon are commonly used in combat bots. Test different materials to see how well they perform.
Quick Tip: Dust and small pieces of debris from the arena can often become stuck to the outside of your bot tires. Make sure to inspect and clean your tires, as needed, to minimize the loss of traction before your next fight.
Understanding gears and how they are used in your robot can be extremely useful. While not necessary for the absolute beginner, many of the components you use (drive motors or servos for example) have gears inside them.
Here is a link to an amazing tutorial on how gears work; written and posted to the web by Bartosz Ciechanowski. It has many interactive visuals used to explain how mechanical motion is transferred by way of gears.