NHRL Rules - 2024

Here are our bot design rule changes for 2024.

Here are our tournament rule changes for 2024.

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Changes from the January rulebook will show up in this color.

The Spirit of The Rules

Above all, we are a builder-centric league. We do not make rules to stifle creativity or to look for ways to disqualify competitors. Instead, we want to make a place where builders feel welcome and safe.

Safety is vital. While we try to not be too restrictive with our rules in general, we must make sure all our fights are safe for competitors, audience, and crew.

• We want fights that are entertaining and fun for competitors and audience.
• We provide both an entry level for new competitors to learn about combat robotics, and the most competitive robot combat in the world for experienced builders.
• We love seeing new and weird ideas in play.
• We don’t mind competitors pushing boundaries, so long as it’s done safely and the result is entertaining.

Builder Conduct Policy

It is a privilege to be part of the Havoc Robotics and Norwalk Havoc Robot League (collectively, “NHRL”) community. Everyone who is associated with NHRL must refrain from illegal, violent, dangerous, or irresponsible conduct that is detrimental to the integrity of and public confidence in the league. We must show respect for others inside and outside our community and we must strive to conduct ourselves in ways that favorably reflect on ourselves, our sport, our teams, the communities we represent, and NHRL. As such, NHRL has established this Builder Conduct Policy (BCP), which applies to existing and former builders, builders who have registered to compete, prospective builders, and members of our social media community (collectively, “Builders”).

The BCP is intended to address and sanction conduct detrimental to the league and sport. In order to uphold our high standards, when violations of this BCP do occur, appropriate disciplinary action must follow.

Expectations and Standards of Conduct

Builders must conduct themselves in a way that is responsible, promotes the values of NHRL, and is lawful. Builders that NHRL determines have engaged in conduct that violates these rules or the values of NHRL including, but not limited to, any of the following (“Prohibited Conduct) will be subject to discipline.

• Actual or threatened physical violence against another person, including dating violence, domestic violence, child abuse, and other forms of family violence;
• Assault and/or battery, including sexual assault or other sex offenses;
• Violent or threatening behavior toward any person in any NHRL setting;
• Stalking, harassment, or similar forms of intimidation;
• Illegal possession of a gun or other weapon (such as explosives, toxic substances, and the like) in any NHRL setting;
• Illegal possession, use, or distribution of alcohol or drugs;
• Possession, use, or distribution of steroids or other performance enhancing substances;
• Crimes involving cruelty to animals as defined by state or federal law;
• Crimes of dishonesty such as blackmail, extortion, fraud, money laundering, or racketeering;
• Theft-related crimes such as burglary, robbery, or larceny;
• Disorderly conduct;
• Crimes against law enforcement, such as obstruction, resisting arrest, or harming a police officer or other law enforcement officer;
• Conduct that poses a genuine danger to the safety and well-being of another person; and conduct that undermines or puts at risk the integrity of NHRL, its facilities, or its personnel.
• Conduct that undermines the integrity of NHRL events and competitions or violates the letter or intent of the BCP.

“NHRL setting” means any physical or virtual location or conveyance used in connection with NHRL activities, including but not limited to event facilities, offices, private or off-site events, workshops, and social media platforms.

Reporting Misconduct

If you have witnessed Prohibited Conduct by a Builder, or are aware of any incident which, if the allegations were true, would constitute a violation of the BCP, you are obligated to promptly submit a report to NHRL’s Commission.

Reports must be sent via email to complaints@nhrl.io, and must contain:

• Your full name
• Your phone number
• Date(s) and time(s) of the incident(s), as applicable
• Any relevant information or context about the nature of the incident, identity of any all parties involved (including the legal first and last name of any individual(s) and contact information, as known or available)
• Any supporting evidence, like photographs, social media activity, emails, complete and unedited screenshots or transcripts, a news article, a police report, or other materials as applicable

Upon receipt of an incident report, the Commission will review it in a timely manner, and open an investigation. The investigation may include conducting interviews with the complainant, the accused, witnesses, and/or may include contacting the authorities if the Commission deems it necessary. The timing and scope of any investigation will be based upon the particular circumstances of the matter. In conducting investigations, the Commission will make reasonable efforts to safeguard requests for confidentiality from complainants or others with information. In addition, the Commission will not tolerate, and will discipline, any retaliation, threats of retaliation, intimidation, harassment, or any other adverse action against anyone who in good faith reports a possible violation or provides truthful information during an investigation.

In certain cases when further investigation is warranted, the Commission may choose to temporarily ban or restrict any individuals who are subject to said investigation until it has concluded, at which time the temporary ban may be lifted or extended or augmented with additional discipline.

Discipline

In the event where a Builder has been found in violation of the BCP, either by being formally charged with a crime or through the course of the Commission’s investigation, the Commission will determine what, if any, disciplinary action will be taken, and communicate its decision with the necessary parties involved. This decision is final and cannot be appealed.

Depending on the nature of the violation and other circumstances, discipline may be a suspension for a fixed or an indefinite period of time, or banishment from the league and/or its digital platforms. Discipline may also include a probationary period and conditions that must be met for reinstatement and to remain eligible to participate in the league. Repeat offenders will be subject to enhanced and/or expedited discipline.

Bot Design Rules

Weight Classes

NHRL offers 3 different weight classes to compete in: 3lb, 12lb and 30lb. All robots must be at or below the maximum weight listed for their respective weight class at the start of the fight. In any given class, additional weight bonuses and exemptions may be allotted to entrants that meet certain criteria set out in this Bot Design Rules section. Competitors can stack weight bonuses, but the total weight of the bot cannot exceed 1⅔ times the weight limit for bots without bonuses.

Weight bonuses are summarized in this table:

Weight Class	Non-Traditional Locomotion Bonus	Multibot Bonus	Maximum Bot Weight
3lb	+1.5 lbs	+1 lb	5 lbs
12lb	+6 lbs	+3 lbs	20 lbs
30lb	+15 lbs	+12 lbs	50 lbs

NHRL has sole and final discretion regarding awarding bonuses to competitors.

Non-Traditional Locomotion Bonus

Any robot that falls outside the definition of a “Traditional Motion System” qualifies for the Non-Traditional Locomotion Bonus. NHRL classifies Traditional Motion Systems as a robot that relies on rotational motion of a component in contact with the ground as its method of locomotion around the arena. This includes all forms of wheels (round, non-circular, spoked, or offset axis) as well as continuous tread, track or belt driven systems. This also includes any robot that uses unpowered rotating objects (wheels, drums, rollers, ball bearings, etc.) as a means of friction reduction with the ground.

Multibot Bonus

Any competitor with multiple independent robot components fighting under a single entrant qualifies for the Multibot Bonus. Each bot component in a Multibot must have independent active control and be capable of influencing the fight. At least 51% of the weight of a multibot must be on bot components with active weapons. Additionally, for a multibot to benefit from the Non-Traditional Locomotion Bonus, only the heaviest component of the bot needs to meet the criterion to qualify for the Non-Traditional Locomotion weight bonus.

The weight of any component of a multibot may not exceed 110% of the ‘base weight’ for its respective weight class, except in the 3lb class. Base weight is defined as the maximum weight the bot can be within the rules without applying the Multibot Bonus. If the bot also qualifies for the Non-Traditional Locomotion Bonus, the additional weight limit is a part of the base weight.

For example, the heaviest segment of a 12lb multibot may not exceed 13.2 lbs. However, if the robot also qualifies for the Non-Traditional Locomotion Bonus, the maximum weight of the heaviest segment increases to 19.8 lbs (18lbs x 110%).

If a competitor’s robot requires the multibot bonus to make weight, but arrives at the cage with a non-functional multibot, the competitor will lose the match by Technical Knockout.

Weight Exemptions

Any bots with flamethrowers, hydraulic-, pneumatic- or ICE-powered weapons systems will be weighed “dry” (without fuel).

Flamethrower bots will be weighed with no fuel in their tanks.

Pneumatic and ICE systems will have their tanks removed for weigh-in. Any tanks used must be commercially available tanks.

Competitors who bring hydraulic systems must declare in advance how much hydraulic fluid is in their system and how much it weighs. The fluid weight will be subtracted from the bot’s scale weight. These bots will be subject to random inspections, where the hydraulic fluid will be removed and measured.

Any active cameras or recording equipment on the bot do not count towards the robot’s weight but must be approved during bot inspection by a Bot Inspector.

Size Requirements

3lb robots must be able to fit into a 30 x 30 x 24-inch box.

12lb and 30lb robots must be able to fit into a 36 x 36 x 36-inch box.

In the case of a multibot, all segments of the robot must fit within the box size together.

Once the match begins, robots are allowed to expand or contract to any size.

Batteries and Power

Bots must have an easily accessible master power cutoff in the form of a switch or removable link (an easily accessible battery connector is an example of a removable link). The power cutoff must be accessible without disassembling the robot in any way. The power cutoff must be able to be deactivated in no more than 15 seconds.

Nominal battery voltage may not exceed 60 volts for 3lb bots, or 75 volts for 12lb and 30lb bots. It is understood that a fully charged battery pack will have an initial voltage above its nominal Voltage.

Any robot system that produces voltages above the robot’s battery voltage limit must be approved by NHRL prior to participating in any competition and may require additional inspection. Email safety@nhrl.io to discuss your design.

Robot Control Systems

Robot controls and communication systems must pass a failsafe test overseen by a Bot Inspector at Bot Inspection in order to compete. In the event of signal loss or transmitter power-down, the bot’s drive system must stop within 30 seconds and weapons must come to a complete stop within 60 seconds.

All robots and multibot components must have a dedicated receiver(s).

Autonomously controlled robots are allowed, but they must still retain a radio control module that can remotely activate and deactivate the robot.

Weapons

All robots must have an active weapon. An active weapon is defined as a weapon or mechanism that operates independently from the robot’s drivetrain or means of locomotion and is clearly designed to influence the opposing robot. In a multibot, at least 51% of the weight of a multibot must be on bot components with active weapons.

“Meltybrains” (bots that can show controlled movement while spinning at rapid speeds), and “Gyro Walkers” (bots that use spinning masses or weapons to generate inertia to induce translational motion) are exempt from this rule. “Thwackbots,” (robots which use momentum created by the robot’s drivetrain to ‘actuate’ an otherwise unpowered weapon) do not qualify as having an active weapon.

NHRL strongly encourages competitors designing a non-conventional active weapon to share their plans with NHRL in advance so confirmation can be given if the weapon is deemed active or not. In the event that a ruling on a weapon is required at a NHRL tournament, the Tournament Stewards will make a ruling once they have been alerted by the Bot Inspector. Here are some examples of criteria the Tournament Stewards will use to make a decision:

• A good-faith explanation of how the weapon is designed to influence an opponent.
• The proportion of bot weight dedicated to the weapon system.

Specific Weapon Classifications

Flame and heat-based weapons are allowed.

This includes but is not necessarily limited to flamethrowers. Robots with flame and heat-based weapons must be able to self-light and self-extinguish. In the case of signal/communication loss with the transmitter, flame and heat-based weapons must self-extinguish in 30 seconds.

3lb robots are allowed up to 6 ounces of fuel. 12lb and 30lb robots are allowed up to 16 ounces of fuel. Consumable fuel and gases do count towards your overall robot weight.

NHRL allows the use of propane, butane and other fuel sources that are gaseous at STP (standard temperature and pressure). Fuels cannot be self-oxidizing and flame systems must not include additional oxidizing systems (e.g. oxy acetylene torches and similar). Matches may be stopped, and your robot disqualified if cage equipment, cameras or safety gear, is being damaged by fire.

Matches may be stopped, and your robot disqualified, if cage equipment, cameras or safety gear, is being damaged by fire from the robot.

Any bot that uses flame or heat-based weapons must go through the NHRL Design Approval Process outlined below.

Rocket motors (also referred to as rocket engines) and fireworks are not allowed.

Drive systems and weapons powered by internal-combustion engines are allowed.

Combustion engines may be manually or electrically started during load in, provided they do not cause the weapon or robot to move. Consumable fuel and gases do not count towards your overall robot weight.

Any bot that uses internal-combustion engines must go through the NHRL Design Approval Process outlined below.

Projectile weapons, both tethered and untethered are allowed.

A fired projectile’s maximum speed may not exceed 150 miles per hour. Additionally, a tethered projectile must not be designed in a way that is likely to become entangled with the opposing robot.

Any bot that uses ramset charges must go through the NHRL Design Approval Process outlined below.

Modular weapon systems are allowed

Modular weapon systems are defined as mechanisms, subsystems, or subassemblies that are interchangeable between fights. For example, a modular weapon system may allow a competitor to choose between a horizontal spinner and a vertical spinner configuration between fights.

No more than 50% of a robot’s weight may change between configurations. Additionally, all configurations of the robot must qualify for the same weight bonuses.

Electrical and shock weapons such as tasers and cattle prods are not permitted.

Weapons that primarily act by obstructing visibility are not permitted.

However, weapons that produce smoke or fog as a by-product of their attack are allowed.

Any weapon that directly targets or that may result in harm to those outside the cage is not permitted.

This includes, but is not limited to lasers, high luminosity or strobing lights, or excessively loud noises.

Weapon Locks

All weapon systems must have a lock that stops their actuation, extension, expansion, rotation, ignition, etc. Weapons that move or rotate must have a lock or be constrained such that movement is restricted in all directions. Weapons that shoot a projectile or gas must have physical means to prevent firing AND block the expulsion of a projectile. Additionally, all means of fuel storage must be designed to default to the closed position if damaged or removed from the robot.

Weapon locks that force the competitor’s fingers to be in the path of the weapon for an extended period of time will not pass bot inspection. Clamps can only be used as weapon locks if they clamp to themselves and not to the bot or any other object.

Other Design Restrictions

Drones are allowed.

Drones can compete at NHRL as long as they adhere to all other design rules. Any competitor that operates a drone must be in compliance with all relevant FAA regulations.

Entanglement devices are not permitted.

An entanglement device is defined as a component, subsystem or armor configuration that is designed to be entangled in the rotational or moving parts of an opponent.

Fabric, foam, and other ablative armor is allowed.

However, ablative armor must not be designed in such a way that it presents a likely entanglement risk. The decision of what is a likely entanglement risk is up to the discretion of NHRL Tournament Stewards.

Liquids expelled from the robot are not permitted with the exception of bubbles.

However, liquids expelled from a robot that become gaseous shortly after leaving the robot and/or before hitting the opponent are permitted. Expelled liquids must be gaseous at STP conditions.

Designs that utilize pneumatics, hydraulics and subsystems using airbags are allowed, but must be approved by NHRL staff through the Design Approval Process (see below).

The NHRL Design Approval Process

Any design which includes pneumatics, hydraulics, combustion engines, flame or heat-based weapons, ramset charges, airbags or which falls outside the parameters outlined in the NHRL Rulebook must be approved by NHRL Safety Staff.

To begin the approvals process, please email safety@nhrl.io at least 3 weeks prior to the competition so that a review of the design can be conducted by NHRL Safety Staff. We cannot guarantee that any proposal sent later will be approved in time for the competition. Robots with unapproved designs shall not be allowed to compete and will not be allowed to remain in the competition venue.

Your email should include sufficient information to communicate/demonstrate your design intent. This can be in the form of hand sketches, pictures, video, CAD models, or written word, etc. During the approval process, builders may be asked to provide additional details as necessary.

Spare Robots and Batteries

Bringing multiple copies of your robot is allowed at NHRL. Spare robots must be as close to exact copies of the original as possible. All copies of robots must pass bot inspection before the bot’s first fight at an event to compete.

For any robot with modular weapon systems OR multiple armor configurations, all spare robots must be compatible with each modular system or armor configuration interchangeably.

The Spirit of the Competition

Have a unique, groundbreaking, wacky or super-secret design that isn’t covered by the rules? At NHRL, we love creative and fun designs that push the boundaries of what can be done in combat robotics. If you are unsure if your robot design qualifies, please contact us at safety@nhrl.io. NHRL Staff would be more than happy to chat with you! We would rather see new and interesting bots fight than disqualify them!

Tournament Stewards may disqualify any robot that has been designed in such a way that skirts or violates the spirit of the competition, whether intentionally or unintentionally. See Spirit of the Rules above.

Open Tournament Format

Tournament Format Summary

For each weight class, there are two separate stages: Qualifying and the Bracket. Not all bots will make it to the Bracket.

Qualifying

To qualify for the Bracket, a bot needs to win two fights over a maximum of three rounds.

The top 25% of the bots (by NHRL ranking) entered will be seeded. For seeding purposes, the number of bots will be rounded up to the next half bracket size. For example, if there are 83 bots entered, the next half-bracket size is 96, and there would be 24 seeds. All other bots will be unseeded. Seeded bots will not fight another seeded bot in the first two rounds of the qualification phase.

In the first round, each seeded bot will fight a random unseeded bot. The remaining unseeded bots will be drawn against each other.

After the first round, the bots that won their first fight will fight another bot that won its first round. The winner of that fight progresses to the single-elimination bracket.

Bots that lose their first-round fight will fight another bot that lost its first-round fight. The loser of that fight is eliminated.

All bots that went 1-1 in the first two rounds of qualifying will then fight one more time - the winner progresses to the single-elimination bracket and the loser is eliminated.

The Bracket

The Bracket phase will be a straight single-elimination bracket ending with a final and a champion. If Qualifying is using a half-bracket (12, 24, 48, 96 bots) the top seeds for the Bracket will receive a first-round bye.

In the Bracket, only bots that went 2-0 in the qualification phase will be seeded. Seed order will be determined first by Qualifying seeding and then (for any unseeded bots that went 2-0 in Qualifying) pre-tournament NHRL ranking. All other bots will be unseeded. No seed will face another seed in the first round of the single-elimination bracket.

There will be no 3rd Place Playoff. Bots that lose in the semi-final can agree to fight each other but this fight would not impact World Championship qualification and would not result in ranking points.

Bots from the Same Team

During Qualifying, bots from the same team will not face each other as long as the team comprises less than one eighth of the bots in that weight class. This effort only applies for a team bringing 2-4 bots per weight class. If a team brings more, they may choose subteams, but one subteam may fight another.

Qualification for the NHRL World Championships

The semifinalists at each Norwalk tournament will qualify for the NHRL World Championships. If a semifinalist has already qualified, the quarterfinalist with the highest pre-tournament ranking will take that qualification spot.

The qualification rules for tournaments outside out of Norwalk will be communicated before those tournaments.

NHRL Freestyle Fights

Freestyle fights are a series of grudge fights run throughout the day that ensure that every builder gets to fight as much as they can. Freestyle fights do not award NHRL rankings points.

All bots that participate in the Freestyle fights must pass safety.

Event Discipline

NHRL Commission

NHRL has created a Commission that will investigate allegations of violations of the Builder Conduct Policy, review safety and other disciplinary issues at events, and impose disciplinary actions if warranted.

Tournament Stewards

There will be two Tournament Stewards at each event. One will be a member of NHRL staff and the other will be a builder. The Tournament Stewards’ job is to make rulings on any possible rules infractions that need dedicated attention. Any resolution needs to be agreed to by both Tournament Stewards. If the Tournament Stewards disagree, no action will be taken against the bot team.

As far as possible, the identity of the Tournament Stewards for the event will be kept hidden so that they will not receive external pressure.

Referees

Referees are empowered to issue warnings, TKO points, and single-point demerits. If a Referee feels that a bot team should face greater disciplinary sanctions, the Referee will report that to the Tournament Stewards.

If a referee deems that a driver is deliberately ignoring Referee or Cage Manager instructions or is fighting in the cage contrary to the spirit of the sport, they will call for a Tournament Steward to come to the cage. The fight will continue. The Tournament Steward will determine the course of action on what they have seen from the fight, from talking to the cage crew and the drivers and from reviewing fight footage, if needed. A decision will be made cageside.

Demerits

To ensure that events run safely and fairly, NHRL has a disciplinary system called Demerits. Any bot that receives 3 Demerits will be disqualified from the event. A disqualified bot is immediately removed from the tournament. Its next opponent receives a bye. In addition, a disqualified bot is not allowed to enter Freestyle fights.

Demerits will be applied to the bot and not individuals. It is the Main Driver’s responsibility to ensure that their team stays safe and within NHRL rules.

In addition to issuing Demerits, Tournament Stewards can disqualify individual bots, and decide that individual competitors must leave the building or the pits. If a bot is disqualified but individuals are not made to leave, those individuals can continue to compete with any other teams that they are registered with for the event.

Single-Point Demerit Infractions

Single-point Demerit can be given by any Referee or tournament director. These can only be given for the following listed infractions:

• Leaving a lipo battery charging unattended.
• Weapon not locked when away from the designated pit table, workshop, bot inspection area, hazard area or inside the cage (unless with express permission from NHRL staff).
• Controlling the bot or activating the weapon before cage doors are closed.
• Working with hazardous materials outside of the Hazard Area.
• Using grinding tools outside of the grinding tent or machine shop.
• Touching a functional, unlocked weapon with a hand or any other human body part.
• Appear cageside with a bot but without a bot badge or wristband.

Any potential infraction not on this list must be sent to the Tournament Stewards for an investigation. The infractions on the list can be updated by the Commission.

Tournament Steward Investigations

An investigation can be triggered by any NHRL member of staff. Competitors cannot trigger an investigation but if they observe something that should be investigated, they should inform the nearest member of NHRL staff they can find.

A Referee or Tournament Director cannot issue a single-point Demerit if this would result in the bot’s disqualification. Instead, an investigation will automatically be triggered that will review all Demerits given to the bot up to that point.

Once the Tournament Stewards receive an investigation request, they will investigate in any way they see fit. This may or may not include talking to builders as part of the investigation. When the tournament stewards have reached a decision, they will inform a member of NHRL staff to relay the decision to the relevant builder. Tournament Stewards can decide to issue any number of Demerit points, disqualify the bot, request individuals leave the pits or the entire premises, retract Demerit points, or do nothing.

To prevent unsettling competitors unnecessarily, competitors will not be informed they are under investigation unless this is strictly necessary. If the Tournament Stewards decided that no action should be taken, the competitors will not be informed that they were under investigation.

Further Disciplinary Sanctions

In extreme cases, further sanctions beyond an event disqualification may be warranted. If this is the case, the Commission will meet to decide. In line with current NHRL policies, these investigations, along with the sanctions, will be kept private between the builder and NHRL.

Fight Rules

Objective

Utilize your robot to disable your opponent’s robot by any means allowable by the tournament and design rulesets. The duration of each fight is 3 minutes, if both entrants are still mobile at the end of the 3 minute timer, the winner will be declared by judges’ decision.

Fight Start

The beginning of a fight is signaled by a countdown followed by the words “Fight, Robots, Fight!” The fight officially begins at the enunciation of the first “F” in “Fight.” During the countdown, robots must be at a full stand-still.

Robots must start the fight in their assigned corner of the arena and must be oriented such that they fit within the constraints of their classes' respective bounding box size.

Fight Results

A fight can be decided in these ways:

Knockout

Any robot that is unable to demonstrate motion will receive a 10 second count-down started by the Referee. If the countdown is completed, the robot will be considered knocked out and the fight ends.

If the robot successfully demonstrates any self-propelled motion during the 10 seconds or the robot is directly engaged by their opponent, the count-down ends and the fight continues.

For a multibot, a knockout countdown will start if more than 51% of the robot is immobile.

A knockout ends the fight immediately. Any further engagement or attacks may be referred to the Tournament Stewards.

Tap Out

All competitors have the option to “tap out” of their fight. This immediately ends the fight, giving their opponent the victory. Tap outs are considered knockouts in NHRL statistics.

Competitors tap out by hitting the TAP OUT button on their side of the cage. If the button doesn’t work, they should inform the Referee immediately that they are tapping out.

A tap out ends the fight immediately. Any further engagement or attacks may be referred to the Tournament Stewards.

Judges’ Decision

If a fight runs the full 3 minutes without a knockout, tap out, or other ending, the winner of the fight is determined by a panel of judges. Competitors must immediately stop engaging their opponent. The Referee will conduct a functionality check to assess each bot’s drive and weapon systems. Every multibot component will undergo the check. The Referee will determine whether the system:

• Appears fully functional
• Appears damaged but operational
• Inoperable or severely damaged

Any multibot components that do not have an active weapon will only have their drive system checked.

The referee will be determining system functionality at the time of the check. The status of the system at the time the fight ends will not be taken into account.

The winner of the fight will be determined by a panel of judges following the NHRL Judging Criteria set out in Appendix A. The judges’ decision is final and cannot be appealed.

Technical Knockout

A Technical Knockout (“TKO”) will be issued when a bot has received 3 TKO Points at a single Open Tournament. TKO Points do not roll over to other Open Tournaments. TKO Points are issued by Tournament Stewards, Referees, and Pit Crew only. If a bot receives a TKO but is not eliminated from the tournament, 3 TKO points are deducted from their total. All remaining TKO Points are still scored against the bot.

Forfeit

If a bot refuses to fight its opponent, this is a forfeit. A forfeit is considered a loss in NHRL statistics while the opponent receives a win in NHRL statistics.

Double Knockout

If neither competitor is engaging after their unstick attempts, then both bots will be counted out. If the count-out is completed and the bots engaged at any point during the fight, then the judges will decide the winner.

If neither bot engaged at all during the fight, the Referee will determine the fight winner via a coin flip.

Fight Stopped

The Referee can stop the fight before the full 3 minutes is over if both bots are stuck together and cannot be easily separated, or there is a safety issue like an arena breach. In this case, the fight will be treated as a Judges’ Decision. The Referee has the final decision on all competitor conduct during a fight.

False Starts

At the start of the match, all parts of all robots must be completely stationary. Any non-kinetic and internal systems should remain in their unpowered and stationary failsafe states until the fight officially begins. For example, flame ignitors should be at roughly ambient temperature and internal flywheels should be stationary.

The only exception to this rule is that ICE systems can be in an “idle” state until the fight begins.

Systems that utilize springs, onboard air compressors, or other potential-energy based systems are permitted to “charge” their system before the match begins, but the charge systems must be inactive at the beginning of the match.

Any bot component that moves out of its unpowered and stationary failsafe state before the fight starts will be deemed to have committed a false start. If no contact is made with the opponent bot, one TKO Point will be given to the offending bot. If contact is made with the opponent bot, the offending bot will receive three TKO Points and an automatic TKO.

Fight Resets

A fight reset may occur at the Referee, event organizer, or production team’s discretion.

When a fight reset is called, robots must stop fighting immediately. Both robots are then repositioned to their starting corners, and the fight timer is reset.

Unstick Attempts

During the course of a fight, robots may get flipped or stuck in an orientation such that they cannot demonstrate self-propelled motion. In each match, competitors are entitled to one unstick attempt from the housebot. However, in the event that the housebot is unable to perform an unstick whether by faults or malfunctions internal or external to the housebot, the referee will notify the competitors and their allotted unstick attempt will be waived.

There is no guarantee that an unstick attempt will be successful. Additionally, it is possible that either robot may get damaged or end up in a less favorable position than they started when the unstick attempt was called.

When an unstick attempt is called, the housebot will drive to the impaired robot and try to right/free/reorient it. The effort will start slowly and deliberately, then gradually become more forceful.

Calling for an unstick attempt does not pause the match, or mandate that your opponent stop attacking.

Unstick attempts must be called for using the button box on the side of the cage. Verbal unsticks can be requested if the button box is not working correctly.

An unstick attempt officially starts at the time of the request and will generally last no longer than 25 seconds.

In the event that a competitor’s opponent has impeded a housebot’s unstick attempt, the housebot driver may spend additional time performing the unstick at their discretion. Additionally, the housebot may retaliate against any robot that takes aggressive action against it, regardless of whether it is with the intent of delaying an unstick.

Pins

A pin occurs when a robot is actively preventing their opponent from moving. This includes, but is not limited to lifting, grappling, blocking, or forcing against a wall. Pins are used by Judges to help score fights.

A pin is counted as a pin when it is held for 5 seconds but it must not last more than 10 seconds. At the end of the pin, the pinning robot must release their opponent by giving them sufficient space to escape.

If the pinning bot does not release the pin within 10 seconds, the Judges will disregard the pin. If the pin results in an entanglement (see below), the Judges will disregard the pin.

Disentanglements

Though NHRL prohibits the design and use of entanglement devices, it is still possible that robots may become entangled with each other by accident. The Referee determines if bots are entangled. Multibot components from the same bot that are entangled with each other cannot be determined as an entanglement.

If a housebot is able to successfully separate two stuck robots, it will not be ruled a disentanglement, nor will it count for either robot’s unstick attempt.

If entanglement lasts more than 10 seconds and cannot be rectified by the house bot, the match will be paused, and the referee will attempt to separate the robots manually.

If the referee is unable to safely separate the robots, or if either robot is unable to drive at the end of the disentanglement, the match will end, and the winner will be determined by judges’ decision.

Hazardous robots and behavior

If the Referee or Tournament Stewards deem a robot to be a hazard to the crowd, crew or competitors, or if a robot is inflicting considerable damage to the arena, the Referee may elect to end the fight early. In this case, the winner is determined by judges’ decision.

If a bot fouls the arena in such a way that the arena’s condition is materially impacted and there is no reasonable application of the fouling material, the bot will be immediately disqualified by the Tournament Stewards and there will be potential for further punishments. Glitter, bubbles, and confetti are not materials that can foul the arena.

Event Rules

Entering the Pits

All competitors must sign a NHRL Waiver Form. All competitors must have a valid wristband to enter the Pits.

Match Readiness

All bots are guaranteed a certain amount of repair time between the end of any given fight and the start of the next fight. 3lb bots get 20 minutes, 12lb bots get 25 minutes, and 30lb bots get 30 minutes.

Any bot that is not ready to fight 10 minutes before its scheduled fight time can use a single-use repair extension of 15 minutes. This extension can only be used once per event and any unused minutes cannot be used later at the same event. The bot will receive 1 TKO point for using the extension.

If the bot is still not ready after the 15 minute extension, or if the extension has already been used, the bot will receive 3 TKO points and an immediate TKO.

The repair extension cannot be used for the Quarterfinals, Semifinals of Finals of the Bracket in any weight class.

Bot Inspection

Before a robot’s first fight at an event, it must pass a bot inspection, during which a Bot Inspector will ensure the bot is in compliance with all design and safety rules. Robots must pass bot inspection before they are able to fight. If the bot has not passed bot inspection before it is due to fight, it will receive 3 TKO points and an immediate TKO.

The bot inspection process consists of:

• Weapon lock/weapon cover check.
• Checking that sharp edges are adequately covered when not fighting.
• Radio fail-safe testing for weapon and drive systems.
• Demonstration of general design requirements.
  • Active weapon and controlled motion.
  • Switch/removable link operation.
  • Any other functional, weight or design requirements specific to the robot’s design or weapon type.
• Multibot component check.
• Robot weigh-in (including alternate powered configurations, spare robots and alternate shells).
• Arena fouling material check.
• Camera equipment approval (if needed).

If the Bot Inspector believes the definition of active weapon is not reached or that a multibot is not capable of influencing a fight, they will contact the Tournament Stewards to make a ruling.

Robots will not pass bot inspection if they are overweight.

All powered configurations of a bot must be inspected before the event along with any alternate robot shells. Any powered configurations or shells that have not passed bot inspection before the first fight will not be eligible to fight at the event. Passive configuration changes (like unpowered forks/wedges, fireproof tape, or anti-drone poles do not need a full bot inspection but can be put through bot inspection to confirm they are not considered an entanglement device.

If material that could foul the arena is found, the Bot Inspector will warn the Main Driver, but the bot will still pass bot inspection.

Configurations And Check-ins

When a team checks into the Pit Desk with a bot, they must bring it in the configuration that they intend to fight with. They may not bring extra configurations to the Pit Desk or beyond. Bots cannot be replaced when they get to the Pit Desk.

Unless a weight check is required, the bot does not need to be visible at the Pit Desk. Configurations do not need to be declared before coming to the Pit Desk.

Pre-Fight Weight Checks

All competitors will be required to weigh their bots before each fight.

If a bot is overweight by up to 2.5oz it will be given 1 TKO point. If the team can quickly reduce the weight, they will be allowed to fight assuming the bot has not received 3 TKO points.

If a bot is over 2.5oz it will receive 3 TKO points and an immediate TKO.

A set of official calibrated NHRL scales will be made available in the pits for builders to use at any time to check their bot weight.

Automatic Pre-Fight Weight Checks

Any bot that has changed its configuration from its previous fight must inform the Pit Desk. The bot will then be weighed before its next fight. If it is overweight, the same sanctions apply as they would for a random pre-fight weight check.

Cage Load-In

Competitors must arrive at the cage with their bot unpowered and with weapon lock installed, their transmitter(s), wristbands and bot badge for the team.

When cageside, all competitors must follow directions from Referees and Cage Managers. Bots cannot use their drive or weapons systems at any time when the doors of the cage are open.

If, during load-in, a bot needs more work done to it than removing the weapon lock, powering it on, or performing a power cycle, the team will receive 1 TKO point and a maximum of one minute to get the bot ready to fight. If the bot is unable to fight after one minute, it will receive 3 TKO points and an immediate TKO.

Bots will be able to perform any tests inside the cage that they wish as long as the test can be completed within 1 minute. If it takes longer than 1 minute, this will incur one TKO point. If it takes longer than three minutes, three TKO points and an immediate TKO will be issued.

If multibot components totaling less than 50% of the bot weight are not working, the team can fight without these components as long as the remaining components would be allowed to fight (i.e. 51% or more of the multibot has active weapons and the remaining components fall within weight rules) or keep the components in the cage but this will have a significant impact on judges’ scores. If the multibot components total more than 50% then an immediate TKO will be issued.

If a competitor leaves the cage area for any reason, they are not permitted to return to the cage area until after the fight has finished.

Safety Rules

Battery Charging

• Any time a battery is charging, it must be attended by a builder or team member.
• Any lithium-chemistry battery must be charged using balance leads.
• If a battery catches fire or presents a safety hazard, make the situation as safe as possible and alert NHRL staff immediately.

Hand and Power Tools

• Safety glasses and other appropriate PPE must be worn while working with power tools in the pits or machine shop.
• Power tools that produce sparks, dust, or shrapnel may only be used in the workshop or in the designated “cutting and grinding” area in the pit.
• Power tools that produce flames or lasers may only be used in the workshop.
• 3D printers must not be left running overnight.

Weapon Locks

A weapon lock is defined as a mechanism or component that will keep your weapon from being dangerous when your robot is not in the cage.

When a weapon lock must be used:

• During robot load-in and unloading from a cage or test box.
• Any time your robot is in transit from one location to another.
• Anytime your robot is powered on at NHRL, unless otherwise instructed by a Referee, Cage Manager, Bot Inspector, or other NHRL safety official.

Robot Testing

All robot testing must be done in a test box. The only exception to this rule is ‘Wheels-up’ testing for robots with a second dedicated switch for their weapon system.

Robots may not be driven on the floor of the pits, around the competition venue, or outside the test box, regardless of their weapon status.

Robot Hazard Station

The Robot Hazard Station is an extension of our pit safety efforts. It ensures that potentially hazardous processes are done in a controlled and safe environment outside of the pits. Failure to use the hazard station appropriately may result in demerit points.

The Robot Hazard Station must be used for the following:

• Loading, filling, pressurizing or depressurizing all h flamethrower, pneumatic, hydraulic, internal combustion engine, jet, rocket engine, ramset charge or airbag systems
• Post-fire robot inspection and clean-up in the event that a robot is rushed out of the building after a fight.

Robot Hazard Station Rules:

• No more than 3 teams with 2 representatives each in the station at a time.
• Use appropriate PPE when working in the station.
• Do not charge batteries in the Robot Hazard Station.
• If recovering from a fire, talk to the hazard station attendant for a check-in

Flammable Gas Container Regulations

If the amount of gas used on a bot is such that it can be fully depleted in less than 60 seconds of continuous firing, it is exempt from this section.

Large volumes of flammable gas on bots must be stored in a container that defaults to the closed position. Examples include:

• "Lighter Filling" bottles where the nozzle must be depressed to release gas.
• Gas tanks that require an active pump or an inert gas to be pumped as a displacement.
• Tanks with a spring-loaded nipple.

These bottles cannot be implemented in a way that permanently depresses the opener. When the bot loses power or the bottle is severed from the rest of the bot, the canister must return to the closed position.

Alcohol

Though alcohol is served at NHRL, it is never allowed in the pits or workshop, nor is any active competitor or team member allowed to drink alcohol during a competition.

Appendix A: Judging Criteria

This criteria covers judging for head-to-head matches for full-combat bots.

Each judge rates the competitors across 3 categories: Aggression, Control and Damage. A judge allocates 6 points to the competitors for each of Control and Damage, and 5 points for Aggression. The bot with the most points is that judge’s choice. If there is a panel of 3 judges, the bot that is chosen by at least two judges wins the match.

When a judges’ decision is required, a recording of the fight will be watched by a panel of 2 judges. If both judges choose the same winner, that bot will win the fight. If the judges choose different winners, a third tiebreaker judge will watch the same recording of the fight and choose the winner.

For the quarterfinals of the single-elimination bracket onwards, a panel of three judges will watch the fight live and each will choose a winner. The bot that is selected as the winner by at least two of the judges will win the fight.

The judging process and number of judges on each panel will only vary from these two scenarios if there are technical issues requiring the activation of contingency plans.

All judges' decisions are final.

For example, consider a match between bots Foo and Bar that goes to a panel of 3 judges:

Judge	Aggression	Control	Damage	Winner
A	Foo 2, Bar 3	Foo 4, Bar 2	Foo 1, Bar 5	Bar 10-7
B	Foo 2, Bar 3	Foo 5, Bar 1	Foo 2, Bar 4	Foo 9-8
C	Foo 2, Bar 3	Foo 3, Bar 3	Foo 2, Bar 4	Bar 10-7

The winner of the match would be Bar, by split decision.

Aggression

Aggression is the intensity and frequency of intentional attacks, preferably with an active weapon. To score points here, the bot needs to make attacks that could conceivably affect the opponent.

Gaining Aggression Points

The key to aggression is attacking intensely and/or frequently with an active weapon, and an intention to affect the opponent. Missed attacks do not count toward aggression.

Whether the attack actually affects the opponent through damage or control is not important when scoring aggression. However, the intent to affect the opponent is important.

For example, a bot that uses a powered lifter to attempt to tilt its opponent against the wall will score aggression points, as they are attacking with an active weapon with an intent to affect them.

If a bot’s weapon is disabled, but it is still attacking with intent, it scores aggression points as if the weapon were working.

A bot that attacks consistently over the length of an entire match should score more aggression points than a bot that clumps all its attacks into a short duration of the match but spends significant portions of the match not attacking.

Losing Aggression Points

If a bot attacks without intent to do damage, even with a functional weapon, it should score even fewer aggression points. For example, striking an opponent’s armor repeatedly with a tapping stick would score very few to no aggression points, as there is no intent to affect the opponent. However, attempting to jam the tapping stick into an opponent’s spinning weapon would score aggression points, as there is an intent to affect the opponent’s weapon systems.

If a bot declines to engage its opponent, does not use its active weapon, or is technically unable to engage for a significant period of time, it should lose aggression points. This includes robots that spend a significant portion of the fight avoiding physical contact. Bots that are clearly attempting to use their active weapon but are unable to due to the actions of their opponent should not be penalized. Note that a bot that drives away from contact briefly to prepare its weapon should not lose aggression points, nor should a bot that shows willingness to attack its opponent but is circling briefly to find an opportunity.

Tiebreaker Considerations

In the case of effectively equal aggression the judges shall slightly favor the robot with the still functional weapon if one bot has lost weapon functionality.

If both bots have seemed to use active weapons equally as frequently, then consider how often they each used passive weapons like fixed wedges as a tiebreaker.

If both bots spend a significant portion of the fight not using their active weapon to attack, then attacks with passive weapons should be considered when determining aggression during those portions of the fight.

A bot that consistently waits for its opponent to engage or otherwise relies on its opponent creating engagements will be treated as less aggressive than a bot that actively searches for attack opportunities. This should only be factored into scoring when the aggression score is effectively at the midpoint between levels in the aggression matrix.

Other Factors

If both bots hit each other with their active weapons simultaneously and one gets sent in the air, both are showing equal aggression.

A bot being faster does not inherently make it the aggressor. A slower bot may demonstrate aggression by consistently moving toward its opponent in an attempt to attack even if the speed differential between the two bots makes this difficult.

Bots do not get aggression points for interfering with the house bot.

When scoring a fight with a multibot entry, consider the aggression of each segment of the multibot. If any portion of a multibot spends a significant portion of the fight avoiding engagement this should negatively impact the entries overall aggression score. This would not apply to a multibot segment that was rendered non-functional. Additionally, a multibot segment without a weapon being used as part of an attack involving an active weapon counts as aggression for the entry as a whole. To the degree practical the overall aggression score for a multibot should be the average of the scores you would assign to each individual segment. For segments that were rendered non-functional during a match their weighting should be balanced based upon the portion of the fight in which they were functional.

Aggression Judging Matrix

• 5-0:
  • This bot used its active weapon to attack its opponent with intent for almost the entire match. The opponent spent almost all of the match not actively attacking with an active weapon using intent.
  • The opponent spent almost the entire match actively avoiding engagement.
• 4-1:
  • This bot frequently used its active weapon to attack its opponent with intent. The opponent occasionally used its active weapon to attack its opponent with intent.
  • This bot often used its active weapon to attack its opponent with intent, but only for part of the match. The other bot rarely or never used its active weapon to attack its opponent.
  • The opponent spent a significant portion of the match actively avoiding engagement.
• 3-2:
  • This bot used its active weapon to attack with intent slightly more than its opponent.
  • Both bots’ active weapons were at least partially disabled, but this bot tried to attack more with its disabled weapon than its opponent.
  • This bot attacked consistently throughout the match with its active weapon. Its opponent bunched its attacks over a shorter period of the match but spent long portions of the match not attacking.

Control

Control is how well a bot dictates the flow of the match. To score points here, a bot will be putting its opponent in a bad spot, like pinning it or getting it stuck.

Gaining control points

The key to control is seeing your opponent put in a bad position. This could include:

• Inverting them
• Pinning them
• Getting them stuck against the wall
• Getting them stuck on a rough patch on the floor
• Getting them stuck on a side that the bot was not capable of self-righting from
• Getting them stuck on debris

Pinning a bot should not count as much as leaving them in a stuck position.

A bot that unsticks its opponent demonstrates more control than a bot that lets the house bot do the unstick. A bot that unsticks itself demonstrates more control than a bot that needs the house bot to unstick it.

If Bot A is able to use Bot B’s weapon against itself, then Bot A is considered to be showing control.

If Bot A acts in a way which prevents Bot B from successfully attacking with their weapon, then Bot A is considered to be showing control.

Following a weapon to weapon impact a robot should only gain control points if the outcome is one of the robots being put in a bad position once the bots have stabilized following the impact.

Losing control points

If a bot successfully pins their opponent but is unwilling to release the pin prior to the completion of the refs 10 count does not gain control points. A bot that is unable to release a pin without house bot intervention does not gain control points.

If a bot sticks itself, that counts as if it was stuck by its opponent (although see the tiebreaker rule below).

A bot should be stuck or inverted long enough to affect the flow of a match in order to lose control points. A brief period of being stuck (e.g. getting a fork stuck in a divot for a second or two) or inverted should not count against a bot for control.

Tiebreaker considerations

If bots seem to control the match equally, shift your focus to each driver’s control of their bot as a tiebreaker. Was the driver in control of their bot, or did they seem to frequently lose control of it? If one bot stuck itself, then the other bot should get more control points.

Other factors

Bots do not get control points for interfering with the house bot.

Long periods of neither bot maintaining control should be considered when determining the final score spread. Frequent, extended periods of no clear controlling bot should bring the overall score closer to an even split.

When scoring a fight with a multibot, focus on the overall control of the entry as a whole. A robot facing a multibot that uses one of the segments of the multibot against another segment of the multibot counts positively for the singular bots control score. Similarly, a multibot entry where the segments regularly interfere with each other counts negatively toward the multibot’s control score.

If a multibot segment is unwilling or unable to interact with the opposing robot this should negatively impact their control score.

In a situation where Bot A pins one multibot segment of Bot B it would gain control points. If another segment of Bot B were to attempt to pin Bot A into the already pinned portion of Bot B that does not gain control points. In this circumstance, if the second segment of Bot B prevents Bot A from releasing a pin this will not count as Bot A being unable to release their pin.

Control judging matrix

• 6-0:
  • This bot pushed the other bot around the cage at will, repeatedly putting them into bad situations while never itself being put in a bad situation.
  • The other bot got stuck far more often.
• 5-1:
  • This bot was able to get the other bot in bad positions in the cage several times, while it got put in bad positions occasionally, but less frequently.
  • The other bot got stuck somewhat more often.
• 4-2:
  • This bot got the other bot in bad positions slightly more often than it was put in bad positions.
  • The other bot got stuck slightly more often.
  • Both bots were stuck in bad positions about the same amount, but the other bot stuck itself in bad positions more.
• 3-3:
  • Both bots seemed to control the match equally.
  • Neither bot seemed to take control of the match.

Damage

Damage is the condition of the opponent’s bot at the end of a match compared to how it started. To score points here, a bot needs to hurt its opponent’s critical systems.

Gaining damage points

Damage is the relative state of the bot at the end of a match, as compared to at the start of the match. The highest damage score is awarded to the complete destruction/disablement of a subsystem, followed by the reduced effectiveness of a subsystem, damage to critical structural components, damage to ablative components, and lastly aesthetic or cosmetic damage.

Self-damage is weighted as being equal to damage from the opponent.

If a bot’s active weapon does not work from the very start of the match, or if its drive is compromised at the very start of the match, this will count as damage.

To score damage points, a bot must alter the state of their opponent’s bot. When scoring damage, consider this chart, where the most damage points is at the top (Class F), and least is at the bottom (Class A). The more damage a bot sustains, the higher its damage class, and the more damage points its opponent will score.

• Class F: At least half of the drive system and all weapon systems on the bot are disabled.
• Class E: At least half of the drive system or all weapon systems on the bot are disabled. This includes removing a spinner’s weapon belt so it no longer spins. An articulated weapon, like a hammersaw, must be completely disabled to count here; that is, both the saw and the arm must be disabled.
• Class D: Reduced effectiveness of drive or weapon systems. This includes at least one wheel removed or damaged such that the bot's ability to drive in a straight line is significantly compromised, disabled powered stabilization features like internal flywheels, a partially-disabled articulated weapon (disabling either the saw or the arm, but not both), or a cut flamethrower line so that the bot sprays fire on itself.
• Class C: Structural damage, like a damaged frame, significant damage to non-ablative armor, removed forks/wedglets, or a wheel damaged in a way that moderately changes a bot’s function. Examples of this would include a wheel being damaged such that the robot is consistently bouncing as the wheel rotates or the robot has some difficulty driving in a straight line, large gouges in a wedge that expose what it was protecting to attack, or wheel guards being removed.
• Class B: Most ablative armor removed from at least one side, small gouges/holes in non-ablative armor that doesn’t significantly hinder function, or a wheel or wheels damaged in a way that doesn’t noticeably change a bot’s mobility. Examples of this would include chunks of the wheel being removed or torn but not impairing the ability of the wheel to spin freely or causing noticeable driving issues.
• Class A: No more than cosmetic damage, like scratches against paint or some ablative armor removed.

Ablative armor is any non-structural component intended solely to absorb damage by being consumed.

Completely running out of fuel (i.e. flamethrower fuel and ICE fuel) does not count as damage, even though it would disable a weapon. Running out of electrical or pneumatic power does count as damage.

For multibots, average out the difference of damage classes between the multibots, rounding towards a higher damage class.

Multibot scoring

For any multibot segments without an active weapon class E damage will be scored as class F damage.

If a multibot segment avoids participating in the fight it will be excluded from the damage calculation.

Example 1: If one half of a multibot finished at class C and the other half finished at class F, consider the bot at class E (Class C is the 3rd damage tier, class F is the 6th damage tier. 3+6=9, 9/2=4.5, rounded up that’s 5 and the 5th damage tier is Class E).

Example 2: For a 3 part multibot consisting of Segment 1 at class B, Segment 2 at class A, and Segment 3 at class F, consider the bot at class C (A+B+F=9, 9/3=3, making the overall damage class C). The same approach applies for a multibot consisting of any number of segments.

Other factors

Bots do not get any damage points for damaging the house bot.

In most cases, any damage done to a bot is considered damage against it, whether it was dealt by its opponent, dealt by a house bot, or self-inflicted. The only exception to this is if a weapon has been stopped through entangled debris in its mechanism from an opponent. In that case, damage is not counted against it.

Damage judging matrix

• 6-0:
  • There are at least 4 classes separating the two bots. For example, one bot is at class F, and the other bot is at class B.
• 5-1:
  • There are 3 classes separating the two bots. For example, one bot is at class D, and the other bot is at class A.
• 4-2:
  • There are 1-2 classes separating the two bots. For example, one bot is at class E, and the other bot is at class F.
• 3-3:
  • Both bots are in the same damage class.

Appendix B: Weapon Lock Examples

A good weapon lock is clearly obvious as a weapon lock, has a sole purpose of being a weapon lock, does not fall out easily (even if the bot is dropped), and can be inserted and removed with one hand.

Here are some good weapon locks: