Magnets
If permitted in the rules of the competition, magnets may be used in combat robots.
- If the arena floor is a ferromagnetic material like iron or steel, you can increase the apparent weight of the bot by having it pull itself down with magnets, making it harder for other bots to lift, push, or flip. Remember that when deployed, these make your drive motors work much harder! Conversely, magnets might help a lifter or suplex bot to get "solid footing" for a better grip when grappling. Consider any benefits or challenges related to your bot's weapon.
- It is possible to use magnets to attract steel parts on other bots. If you become stuck and can’t release the other bot, though, you may draw a forfeit or a loss.
This calculator may be useful for force estimates.
Permanent magnets
Rare-earth neodymium magnets are extremely powerful and can provide a significant advantage to a robot. If used on the bottom of your bot to add downforce the robot can have the pushing power of a much heavier robot. Also, with the increased down-force but no extra mass, robot acceleration can increase dramatically if the motors can provide the needed power. There are drawbacks to using permanent magnets. Loose debris in the arena can become attracted to them resulting in the robot becoming high centered. Another drawback is that these magnets attract all the time which can make safely handling the robot challenging, especially in larger robots.
- Safety:
Electromagnets
A simple coil of insulated wire around a suitable core material makes an electromagnet. Typically these require a lot of power and are typically used intermittently, e.g. to hold the bot to the floor during an attack. Because of their weight and added design complexity, electromagnets are rarely used.