Robot combat is a type of robot competition in which custom-built machines fight using various methods to incapacitate each other. The machines have generally been remote-controlled vehicles rather than autonomous robots. Robot combat competitions have been made into television series, including Robot Wars in the UK and BattleBots in the US. These shows were originally broadcast in the late 1990s to early 2000s and experienced revivals in the mid-2010s. As well as televised competitions, smaller robot combat events are staged for live audiences such as those organized by the Robot Fighting League. Robot builders are generally hobbyists and the complexity and cost of their machines can vary substantially. Robot combat uses weight classes, with the heaviest robots able to exert more power and destructive capabilities. The rules of competitions are designed for the safety of the builders, operators, and spectators while also providing an entertaining spectacle. Robot combat arenas are generally surrounded by a bulletproof screen. Competitor robots come in a variety of designs, with different strategies for winning fights. Robot designs typically incorporate weapons for attacking opponents, such as axes, hammers, flippers, and spinning devices. Rules almost always prohibit gun-like weapons as well as other strategies not conducive to the safety and enjoyment of participants and spectators.

History

Among the oldest robotic combat competitions extant in the United States are the "Critter Crunch" (founded about 1987) in Denver and "Robot Battles" (founded in 1991) based in the southeastern U.S. Both events are run by members of the "Denver Mad Scientists Society".

Rules

Robot combat involves remotely controlled robots fighting in a purpose-built arena. A robot loses when it is immobilized, which may be due to damage inflicted by the other robot, being pushed into a position where it cannot drive (though indefinite holds or pins are typically not permitted), or being removed from the arena. Fights typically have a time limit, after which, if no robot is victorious, a judge or judges evaluate the performances to decide upon a winner.

Weight classes

Similar to human combat sports, robot combat is conducted in weight classes though with maximum limits even in the heaviest class. Heavier robots can exert more power and have stronger armor and are generally more difficult and expensive to build. Class definitions vary between competitions. The below table shows classifications for two organizations: the UK-based Fighting Robots Association (FRA) and the North American SPARC. There are also competitions specifically for Lego combat robots Most televised events are heavyweights. It's worth noting that the definitions of each weight category have changed over time - with European (FRA) rules for heavyweights advancing from 80 kg, to 100 kg, to 110 kg over time. Currently Battlebots has a weight limit of 250 lb. To encourage diversity of design, rules often give an extra weight allotment for robots that can walk rather than roll on wheels.

Safety precautions

Given the violent nature of robot fighting, safety is a central factor in the design of the venue, which is generally a sturdy arena, usually constructed of steel, wood, and bullet-resistant clear polycarbonate plastic. The smaller, lighter classes compete in smaller arenas than the heavyweights. Competition rules set limits on construction features that are too dangerous or which could lead to uninteresting contests. Strict limits are placed on materials and pressures used in pneumatic or hydraulic actuators, and fail-safe systems are required for electronic control circuits. Generally off-limits for use as weapons are nets, liquids, deliberate radio jamming, high-voltage electric discharge, untethered projectiles, and usually fire (allowed in heavyweight).

Robot fighting associations

The sport has no overall governing body, though some regional associations oversee several events in managerial or advisory capacities with published rulesets. These include: The major televised competitions have operated outside of these associations.

Combat robot weaponry and design

An effective combat robot must have some method of damaging or controlling the actions of its opponent while at the same time protecting itself from aggression. The tactics employed by combat robot operators and the robot designs that support those tactics are numerous. Although some robots have multiple weapons, the more successful competitors concentrate on a single form of attack. This is a list of most of the basic types of weapons. Most robot weaponry falls into one of the following categories:

Inactive weaponry

Inactive weaponry does not rely on a power source independent from a robot's mobility. Many modern rulesets, such as the rebooted versions of BattleBots and Robot Wars, require robots to have an active weapon to improve the visual spectacle, thus eliminating certain designs such as torque-reaction axlebots and thwackbots, and requiring other designs such as wedges and rammers to incorporate some other kind of weapon.

Spinners

Spinners are weaponry based around blades, cylinders, discs, or bars rotating at high speed around an axis. This is among the most popular and destructive forms of weaponry, thanks to its potential to quickly deliver a high amount of kinetic energy over a small area.

Control bot weaponry

Hammers and axes

Interchangeable weaponry

It is increasingly common for robots to have interchangeable weaponry or other modular components, allowing them to adapt to a wide range of opponents and increasing their versatility; such robots are often referred to as "Swiss army bots", in reference to Swiss army knives. Arguably the earliest example was Robot Wars Series 1 contestant Plunderbird, which could change between a pneumatic spike and a circular saw on an extendable arm. Successful Swiss army bots include Robot Wars Series 6 champion Tornado, BattleBots 2016 runner-up Bombshell, Battlebots 2020 quarterfinalist and 2023 semifinalist Ribbot, and top-ranked US Beetleweight Silent Spring. Sometimes, robots that were not originally Swiss army bots have had their weapons changed or altered on the fly, typically due to malfunctions. In BattleBots 2015, Ghost Raptor's spinning bar weapon broke in its first fight; builder Chuck Pitzer then improvised new weapons for each following fight, including a "De-Icer" arm attachment which it used to unbalance and defeat bar spinner Icewave in the quarter-finals.

Prohibited weaponry

Since the first robot combat competitions, some types of weapons have been prohibited either because they violated the spirit of the competition or they could not be safely used. Prohibited weapons have generally included: Individual competitions have made exceptions to the above list. Notably, the Robotica competitions allowed flame weapons and the release of limited quantities of liquids on a case-by-case basis. The modern series of BattleBots also permits the use of flamethrowers and, as of 2016, untethered projectiles, provided that the latter are merely for show. Competitions may also restrict or ban certain otherwise legal weapons, such as banning spinners and other high-power weapons at events where the arena is not able to contain these weapons, and the new Battlebots recently banned usage of carbon dioxide gas. A well-known example of this is the Sportsman ruleset. Arena traps have also been granted exceptions to the list of prohibited weapons. Robot Wars in particular used flame devices both in the stationary traps and on one of the roaming "House Robots".

Unusual weaponry and tactics

A very wide variety of unusual weapons and special design approaches have been tried with varying success and several types of weapons would have been tried had they not been prohibited.

Unusual propulsion

The great majority of combat robots roll on wheels, which are very effective on the smooth surfaces used for typical robot combat competition. Other propulsion strategies do pop-up with some frequency.

Robot-sumo

Robot-sumo is a related sport where robots try to shove each other out of a ring rather than destroy or disable each other. Unlike remote-controlled combat robots, machines in these competitions are often automated.