Safety

Overview

Safety is always the #1 priority at all times when it comes to robot combat. While things may look dangerous and exciting in the cage, we need to ensure that that excitement actually stays in the cage. Below you can find some safety information related to combat robotics;

Rocket Motors

Rocket motors, also sometimes referred to as rocket engines, are growing more common as a weapon in combat robotics. There are special safety considerations that must be made while using rocket motors.

Total Impulse & Peak Thrust

The total impulse of all rocket motors on a robot cannot exceed 80 N*s, this includes rocket motors split across multiple bots in a multi-bot configuration.

The peak thrust of your motor(s) also should not be enough to lift the robot off the ground.

Installation

Rocket motors should be fully constrained in a tight tube or clamp that holds onto 50% or more of the outside surface area of the rocket motor. In addition, the back of the rocket motor should be retained, to reduce the risk of the motor coming out of the bot. If possible, design your robot in such a way that the rocket motor can be installed at the cage quickly, rather than needing to be installed in the pits and brought to the cage.

Deployment Charge

Most rocket motors available commercially include a deployment charge, which is a secondary small explosive charge that will expel hot gasses from the top of the motor a set amount of time after the motor itself has burned out. If possible, booster motors (with a delay of 0 or no deployment charge) should be used. If it is not possible to use a booster motor, the deployment charge should be removed from the motor.

Igniters

Rocket motors are ignited using an electronically-initiated match, or e-match for short. These are also commonly referred to as igniters or initiators (although technically e-matches and initiators are different things, they serve a near-identical purpose in rocket motors). It is recommended not to use Estes e-matches, as they are more prone to misfires than other brands. MJG Firewire Initiators are recommended, as they generally have the lowest misfire rate. They are also the only commercial initiators that can be acquired without a license.

Igniters should not be installed in rocket motors until the bot is in the cage! Your electronics should be powered on before the igniter is put into the motor, in case there is an unexpected signal that triggers it on startup. Igniters must be inserted into the bot while the motor is facing into the cage.

Unloading & Misfires

If a bot has used its rocket motor more than 15 seconds before the end of a fight, it can be unloaded as a normal bot. If it has been less than 15 seconds, the cage manager may wait to ensure there is no secondary charge (such as a deployment charge or a smoke grain) still burning. After this time the bot can be unloaded as per normal.

If a bot has a rocket motor but does not fire it during the match, it is treated as a misfire. Misfires, also commonly referred to as hangfires, are when the signal is given to a rocket motor to fire, but for unknown reasons it does not. This may be due to a bad igniter, low power to the igniter, a wet motor grain, or a number of other reasons. The important thing is that the motor is still treated as live. At the conclusion of the fight, a hangfire bot must sit idle for at least 60 seconds after the match has concluded. Before being allowed to unload, the cage manager will cut the leads on the igniter and, if possible, remove the igniter from the motor. After this the bot must sit for at least another 60 seconds, after which it can be unloaded as per normal.

Destroyed Motors

If a bot has a rocket motor that is hit by the competitor's weapon and receives damage, it is treated as a hangfire (see above), unless it has been already fired. In addition to the hangfire response described above, the debris from a destroyed motor will require additional cleaning precautions. Any debris in the cage or on other bots should be removed with a soaking wet paper towel, which is then disposed of immediately.