NHRL Rules - 2023
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Builder Conduct Policy
It is a privilege to be part of the Havoc Robotics and Norwalk Havoc Robot League (collectively, “Havoc”) community. Everyone who is associated with Havoc 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 Havoc. As such, Havoc Robotics 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 Havoc, and is lawful. Even if the conduct does not result in a criminal charge or conviction, Builders found to have engaged in any of the following conduct will be subject to discipline.
Prohibited Conduct includes but is not limited to the following:
- 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 Havoc 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 Havoc 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 Havoc, its facilities, or its personnel.
“Havoc setting” means any physical or virtual location or conveyance used in connection with Havoc activities, including but not limited to event facilities, offices, private or off-site events, workshops, and social media platforms.
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 Havoc’s leadership.
Reports must be sent via email to firstname.lastname@example.org, 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, Havoc 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 Havoc deems it necessary. The timing and scope of any investigation will be based upon the particular circumstances of the matter. In conducting investigations, Havoc will make reasonable efforts to safeguard requests for confidentiality from complainants or others with information. In addition, Havoc 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, Havoc 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.
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 Havoc’s investigation, Havoc will determine what, if any, disciplinary action will be taken, and communicate its decision with the necessary parties involved.
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 with an opportunity to return, with Havoc’s approval, after a specified period of time. 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
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 allowances may be allotted to entrants that meet certain criteria.
Non-Traditional Motion Bonus
Any robot that falls outside the definition of a “Traditional Motion System” qualifies for the Non-Traditional Motion 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.
Any competitor with multiple independent robots fighting under a single name qualifies for the Multibot Bonus. Each bot in a Multibot must have independent active control and be capable of influencing the fight. Only the heaviest bot in a multibot must have an active weapon. Additionally, for a multibot to benefit from the Non-Traditional Locomotion Bonus, only the heaviest segment of the bot needs to meet the criterion to qualify for the weight bonus.
The weight of any segment of a multibot may not exceed 110% of the ‘base weight’ for its respective weight class, except in the 3lb class. If the bot also qualifies for the Non-Traditional Locomotion Bonus, the additional weight may also be factored into the base weight.
The 2-round Qualifier, summarized
Starting in March, our preliminary round for all weight classes will be updated to a 2-round Qualifier. Any bot that goes 0-2 in the Qualifier will be eliminated. All other bots will be seeded into the bracket depending on their performance in the Qualifier.
Seeding the Qualifier
Bots will be seeded into the first round of the Qualifier on the Tuesday before the event, in a bracket reveal livestream.
Any bots from the same individual builder will not meet in the Qualifiers, up to a maximum of 4 bots. They will also not meet in the bracket, as long as all related bots win all their Qualifier fights, in order to reduce opportunities for tactical forfeits.
To create the initial seeds for the Qualifiers, we will use the a seeding rubric based on a bot’s experience level.
- Level 1: Bots that have fought at NHRL before.
- If bots are tied in rank, they will be seeded randomly.
- Any unranked Level 1 bots (bots who haven’t fought at NHRL since 2021) will be seeded randomly below the ranked bots.
- Level 2: Bots that have fought outside of NHRL.
- These bots will be seeded randomly within the level.
- Level 3: New bots, from experienced builders.
- These bots will be seeded randomly within the level.
- Level 4: New bots, from new builders.
- These bots will be seeded randomly within the level.
Once we have an ordered list of Qualifier seeds, we do not have to worry about Levels anymore; we will go off the ordered list instead.
Bracket seeds are different from Qualifier seeds. We give bots Qualifier seeds the Tuesday before the event. We give bots bracket seeds based on their performance in the Qualifiers.
There are four kinds of Bracket seeds we can give a bot.
- Top seed - the highest seeds in the bracket, with the easiest path through the bracket.
- Upper-middle seed
- Lower-middle seed
- Bottom seed - the lowest seeds in the bracket, with the hardest path through the bracket.
Most bots will have to win a fight to earn a spot in the bracket. Bots with high Qualifier seeds are guaranteed to make the bracket, but will need to win a fight to earn a top bracket seed. Some bots will be eliminated before the bracket begins.
The Four Qualifier Groups
There will be four groups of bots in the Qualifiers.
In the first round of Qualifiers, we will have the Challenger Group and the Rival Group.
In the second round of Qualifiers, we will have the Boss Group and the Last Chance Group.
- Boss: The highest-seeded bots start the Qualifiers here, getting a bye in Qualifiers Round 1. They will be joined by winners from the Challenger Group.
- Challenger: This group is made up of the next-highest seeded bots, and will be twice the size of the Boss Group. This group fights in Qualifiers Round 1. The winners from this group challenge the Boss Group, while the losers have to go to the Last Chance Group.
- Rival: This group is made up of all remaining bots that did not go into the Boss or Challenger Groups. This group fights in Qualifiers Round 1. The winners from this group get a bye in Qualifiers Round 2 and are seeded directly into the bracket, while the losers have to go to the Last Chance Group.
- Last Chance: This group fights in Qualifiers Round 2. The winners from this group will make it into the bottom of the bracket, while the losers are eliminated. Bots eliminated this way will be eligible to fight Freestyle fights.
|Round||Group||On win||On loss|
|Qualifiers Round 1||Challenger||Go to Boss Group||Go to Last Chance Group|
|Qualifiers Round 1||Rival||Get a Lower-Middle bracket seed and a Qualifiers Round 2 bye||Go to Last Chance Group|
|Qualifiers Round 2||Boss||Get a Top bracket seed||Get a Upper-Middle bracket seed|
|Qualifiers Round 2||Last Chance||Get a Bottom bracket seed||Eliminated|
Boss Group forfeits
If a bot forfeits their Boss Group fight, they get a Bottom bracket seed. This is to discourage tactical forfeits in a Boss Group fight.
If a bot taps out of their Boss Group fight immediately after the start of the match, clearly showing no attempt to actually fight, we will consider it a forfeit in this case.
Bots from the same team
In the Qualifiers, we will make every effort to ensure that bots from the same team will not face each other. We will extend a similar effort to the bracket, but with a caveat: we can only ensure that all bots from the same team will not face each other early in the bracket as long as all of their bots win all their Qualifier matches. Any bot that loses a Qualifier fight may face a related bot early in the bracket.
This effort only applies for a team bringing 2-4 bots. If a team brings more, they may choose subteams, but one subteam may fight another.
Number of bots in each group
For information on how we determine the number of bots in each group, click here.
The single-elimination bracket
All bots will be placed into the single-elimination bracket according to how they did in the preliminary round.
At this point, the event will run with standard single-elimination brackets. All brackets will have an additional fight between the losers of each semifinal fight to determine third place.
Qualification for the NHRL World Championships
The top 4 bots of each bracket will qualify for the NHRL World Championships at the end of the year.
If a bot that has already qualified earlier in the year makes it into the top 4 again, the highest-ranked bot that lost its Quarterfinals fight (using rankings from before the event started) will qualify.
If there is a tie in the rankings, then all tied bots qualify.
Important: You may choose to forfeit a qualification slot. However, you may not gift your slot to another builder.
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.
All bots that participate in the Freestyle fights must pass safety.
Many Freestyle Fights will happen in the Titanium area at NHRL. This area allows for 3lb and 12lb Sportsman fights. Note that we reserve the right to decline a fight to certain 12lb Sportsman bots if we feel they’re a hazard to the cage.
All entrants 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.
At the end of your allotted repair time, you MUST check in with Pit staff for a status update. In certain circumstances, additional time may be available to builders before their next match, however, this is ultimately determined by match schedule and queuing time.
Builders who are not prepared for their upcoming match at the end of their repair window may be forfeited at the discretion of Pit staff, referees, or an event organizer.
Disclaimer: Any builder bringing multiple robots will be expected to manage their repair time effectively. NHRL does not guarantee extra time for builders who bring multiple robots, nor do we guarantee that repair windows will not overlap.
Due to scheduling and bracket structure, we cannot guarantee that any competitor will have the same amount of repair time as their opponent, only that each robot will have at least 20/25/30 minutes of repair time dependent upon their weight class.
Match Queuing, Cage Load-in and Unloading
When queuing for, loading, and unloading from your match, follow the instruction of event staff. Failure to comply may result in unnecessary scheduling delays, confusion or hazards and may be penalized via the demerit system in extreme cases. If you are unsure what to do or where to go, seek out the proper personnel for assistance or inquire at the “Pit Watch” desk.
At NHRL, safety is our #1 priority at all times when it comes to robot combat. While combat may look dangerous and exciting in the cage, we work hard to ensure that that excitement stays in the cage. Our safety rules extend to a variety of processes and locations including but not limited to safety inspection, pit behavior, and match load-in and unloading. Failure to comply with safety rules and procedures may result in a penalty via demerit system at least, all the way up through forfeiture from an event, or a ban period.
At NHRL, we use an escalating system of consequences, known as the Demerit system. Typically one infraction results in one demerit. However, Referees, Pit-watch staff, Safety officials or Event organizers may assign multiple demerits at their discretion depending on the severity of the infraction. Demerits are recorded by builder, not by team or robot. If a builder is associated with multiple robots, demerits will be recorded on all of their Builder/Robot ID tags. Demerits accrued reset after each event.
- 🟨 1st infraction: Yellow Card: Warning
- 🟧 2nd infraction: Orange Card: Match forfeit
- 🟥 3rd infraction: Red Card: Event forfeit
- ⬛️ 4th infraction: Black Card: Year forfeit
Each infraction recorded is accompanied by a debrief, during which a referee or safety official will discuss the incident and how to improve safety. We understand that accidents happen, especially in high stress environments. If you receive a demerit, don't panic—it is not a personal slight. We will do everything in our power to ensure a safe environment for all competition attendees, and will work together to correct the safety issues in question.
Demerits may also be given out for unsportsmanlike behavior. At NHRL we strive to create a competitive, comfortable, and fun environment.
At the beginning of every event, robots must pass a safety inspection, during which a safety official will ensure your robot is in compliance with all design and safety rules. Robots that do not pass safety inspection will be unable to compete. Safety inspection will only be open for a limited period of time, so be sure to get your robot checked as early as possible. Contact pit staff, safety officials or an event organizer for specifics on inspection availability.
This process includes:
- Robot weigh-in
- Including alternate configurations and spare robots.
- Weapon lock/weapon cover checks
- 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 robots design or weapon type (see Bot Design Rules for specifics)
All configurations of your bot must pass safety. If you configure a bot in a way that safety has not seen, you risk a demerit, forfeit, or other sanction.
After successful completion of safety inspection, your team captain or robot driver will be given a robot badge to attach to their builder ID. This must be kept with you at all times, as demerit marks are recorded on it.
The Pits & Robot Repair
In order to ensure a safe environment for both builders and staff, it is imperative that builders are not only aware of, but fully compliant with our pit safety rules. Just because your bot isn’t actively fighting doesn’t mean it, or the environment around it, is not hazardous!
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 and power tools do not mix.
- 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.
Though not required, it is good practice to have a lipo-safe bag and fireproof resistant gloves nearby when charging.
Hand and Power Tools
- Safety glasses and other appropriate PPE must be worn while working with power tools in the pits or machine shop. See a member of pit watch, safety inspection, or workshop staff if you are unsure what qualifies as appropriate PPE.
- 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 shop.
- 3D printers are allowed, but may not be left running overnight.
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 ring. Weapon locks are required during loading and unloading into the ring or test boxes. All robots with an active weapon must have a weapon lock. Failure to follow rules will result in a penalty via the demerit system.
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, pit-watch staff, or safety official.
What works well as a weapon lock:
- A metal pin, plug or stop that prevents any rotating or translating weapon from spinning, ideally painted or marked with a bright color.
- A plastic or foam cover (such as a pool noodle) over sharp edges, forks or lifters.
What isn't great as a weapon lock:
- Your hand or any other part of your body
- Anything that can easily fall out or be dislodged.
- Tools such as vice-grips, screw drivers, or clamps
- Weapon locks should be a dedicated safety measure and not something that can be misplaced, misconstrued or used for another purpose.
Testing your Robot
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 and/or minibots may not be driven on the floor of the pits, around the competition venue, or outside the test box, regardless of their weapon status.
Utilize your robot to disable your opponent’s robot by any means allowable by the tournament and design rulesets. The duration of each match 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.
These rules only cover head-to-head fights. NHRL does occasionally run fights with more than two competitors (“rumbles”), but they are run as exhibitions. Exceptions for exhibition fights are listed below.
The beginning of a match is signaled by an 8 second countdown followed by the words “Fight, Robots, Fight!” The match 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 match 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 as outlined here.
A false start occurs when any bot begins moving or activating their weapon before the match start countdown is complete.
False starts are considered to be unsportsmanlike and may be subject to penalty. False starts may additionally trigger a match reset, additional repair time for the bot that did not false start, or in extreme cases, a forfeit loss for the offending robot.
A fight can end in these ways:
Any robot that is unable to demonstrate controlled motion will receive a 10 second count-down. If the countdown is completed, the robot will be considered knocked out and the fight ends.
If the robot successfully demonstrates controlled motion during the 10 seconds or the robot is directly engaged by their opponent, the count-down ends and the match continues.
A robot is considered to be displaying controlled motion if they are capable of moving to a desired quadrant of the cage in a reasonable amount of time and can turn to face the opponent favorably.
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 will be considered unsportsmanlike behavior and may be subjected to penalty via demerit system.
All competitors have the option to “tap out” of their match. This immediately ends the match, giving their opponent the victory.
Note that tap out is not considered a “forfeit.” A forfeit implies that the fight was never contested. 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.
If a fight runs the full 3 minutes without a knockout, tap out, or other way of ending, it ends. Competitors must immediately stop engaging their opponent; however, as long as the cage door is not open or in the process of being opened, a competitor may drive around or spin their weapon without engaging their opponent to show which systems on their bot are still functional.
The winner of the fight will be determined by a panel of judges. There are usually 3 judges on a panel, but sometimes there may only be a single judge, if circumstances dictate that.
If both robots are disabled simultaneously, the referee may choose to count them both out at the same time.
If the countdown finishes uninterrupted, and neither bot shows signs of movement, then the fight will be treated as a Judge’s Decision, as above.
Fight stopped by referee
The referee has the option of stopping a fight before the full 3 minutes is over. This generally happens 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 Judge’s Decision, as above.
A fight reset may occur at the referee, event organizer, or production team’s discretion. This could be for a variety of reasons including but not limited to technical faults within the box or facility, safety concerns, or false starts.
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.
During the course of a fight, robots may get flipped or stuck in an orientation such that they cannot demonstrate controlled movement. In each match, competitors are entitled to one unstick attempt from the house bot. However, in the event that the house bot is unable to perform an unstick whether by faults or malfunctions internal or external to the house bot, the referee will notify the competitors and their allotted unstick attempt will be waived.
IMPORTANT: 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 may be initiated automatically in the event that a robot cannot demonstrate controlled motion. Alternatively, competitors may verbally call for their unstick attempt at any point in the match when their mobility is impaired, unless they are being actively engaged by their opponent.
An unstick attempt officially starts once the house bot has made contact with the immobile robot and will generally last no longer than 20 seconds. Unstick attempts may be requested verbally, or by hitting the “Unstick” button on the button box.
In the event that a competitor’s opponent has impeded a house bot’s unstick attempt, the house bot driver may spend additional time performing the unstick at their discretion. Additionally, the house bot may retaliate against any robot that takes aggressive action against it, regardless of whether or not it is with the intent of delaying an unstick.
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.
A pin may not last more than 10 seconds. At the end of the pin, the offending robot must release their opponent by giving them sufficient space to escape.
Holding a pin for longer than 10 seconds, or giving an opponent insufficient space, is considered unsportsmanlike behavior and may be penalized via demerit system. It is at the referee’s discretion to determine how much space is sufficient.
Though NHRL prohibits the design and use of entanglement devices, it is still possible that robots may become entangled with each other by accident.
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.
During disentanglement, the referee will attempt to free both robots such that both their drivetrains and weapon systems are in operable condition.
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.
Additionally, if robots get entangled multiple times in the same match, the match will be ended and the winner will be determined by the judge's decision.
Hazardous robots and behavior
If the referee or event staff 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.
Purposeful damage to the arena is considered to be both unsportsmanlike and unsafe, and will be subject to penalty. This includes but is not limited to a forfeit loss for the offending robot.
If a fight goes the full 3 minutes, or if the referee stops the fight early for any reason, the fight goes to the judges.
Judges score using the criteria Aggression (5 points), Control (6 points), and Damage (6 points). The bot that gets the most total points from a single judge gets that judge’s vote. The bot with the most judges’ votes wins.
We will almost always have a panel of 3 judges deciding fights. However, there may be times when we would be forced to use a single judge to decide a fight.
Judges’ decisions at NHRL are final and cannot be appealed. Judges’ names are not released with their scores.
During an event, competitors are not allowed to ask who judged a fight, nor are they allowed to talk to the judges, nor are they allowed to ask for an explanation of why the judges voted the way they did. Any competitor who confronts an NHRL staff member about their judges’ decision risks a demerit.
After an event, competitors may request more information about a particular judges’ decision. Information regarding this will be posted on this wiki soon.
For example, the heaviest segment of a 12 pound multibot may not exceed 13.2 lbs. However, if the robot also qualifies for the shuffler weight bonus, the maximum weight of the heaviest segment increases to 19.8 lbs (18lbs x 110%).
Competitors may choose to forgo their multibot bonus so long as their robot still meets the base weight for their weight class. If a competitor’s robot requires the multibot bonus to make weight, but arrives at the cage with a non-functional multibot, the match will be forfeited.
Any active cameras or recording equipment on the bot do not count towards the robot’s weight, but must be approved during safety inspection by an event organizer or head referee.
|Weight Class||Non-Traditional Locomotion||Multibot||Absolute Maximum|
|3lb||+2 pounds||+1 pounds||6 pounds total|
|12lb||+6 pounds||+3 pounds||21 pounds total|
|30lb||+15 pounds||+8 pounds||53 pounds total|
Batteries and Power
Bots must have an easily accessible master power cutoff in the form of a switch or 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 and may require additional inspection. Email email@example.com to discuss your design!
Battery charging must be done safely! Batteries may be charged within your robot, except for robots with flame or heat-based weapons. Unsafe charging procedures may result in a penalty via the demerit system.
Safe charging practices:
- Inspect batteries for damage or puffiness before charging.
- A team member must be present while a battery is charging.
- Balance charge leads must be used for any OTS battery that has them.
- Keep a sand bucket or liposafe bag nearby.
- Set an appropriate charge rate based on your battery.
While not a requirement, it is a good practice to make sure your robot has enough power to be idle for up to 3 minutes prior to the start of your fight.
Robot Control Systems
Robot controls and communication systems must pass a failsafe test. 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 multibots 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.
3 pound robots must be able to fit into a 30 x 30 x 24 inch box.
12 and 30 pound 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.
All entrants 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.
“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.
In a multibot, only the heaviest bot is required to have an active weapon.
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.
Addendum on specific weapon classifications
Flame and heat-based weapons are allowed. This includes but is not necessarily limited to flamethrowers and low or medium-power rocket motors. 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 8 ounces of fuel. 12lb and 30lb robots are allowed 16 ounces of fuel. Consumable fuel and gasses 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.
Rocket motors (also referred to as rocket engines) and fireworks are not allowed as of May 2023. This may change in the future.
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 to move. Consumable fuel and gasses do count towards your overall robot weight.
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.
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.
Designs that utilize pneumatics, hydraulics and subsystems using airbags are allowed, but must be approved by NHRL staff through the Design Approval Process.
The NHRL Design Approval Process
Any design that falls outside the parameters outlined in the NHRL Competition Handbook, OR that includes airbags, pneumatic or hydraulic systems MUST be approved by NHRL Staff.
To receive approval or discuss your robot design, please email firstname.lastname@example.org at least 3 weeks prior to the competition. We cannot guarantee that any proposal sent later will be approved in time for the competition.
Your email should include sufficient information to communicate/demonstrate your design intent. This can be in the form of hand sketch, pictures, video, CAD models, or written word, etc. During the approval process, builders may be asked to provide additional details as necessary.
Spare Robots & Batteries
Due to the fast pace of the competition, bringing multiple copies of your robot is allowed and encouraged at NHRL. Spare robots must be as close to exact copies of the original as possible. All copies of spare robots must pass safety inspection before competing.
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.
NHRL highly encourages competitors to bring spare batteries! Builders are only guaranteed 20, 25 or 30 minutes in between matches dependent upon their weight class for repair and recharge, which may not be enough to fully recharge a battery.
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.
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.
Liquids expelled from the robot are not permitted. 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.
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.
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 email@example.com. NHRL Staff would be more than happy to chat with you! We would rather see new and interesting bots fight than disqualify them!
Event Organizers, Safety Inspectors, or Head Referees 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.
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.
The basic rules...
- All robots must have a weapon lock that prevents any spinning weapons from moving outside of the cage.
- All robots must have a way to turn off power without disassembling the robot.
- All robots must pass a radio fail safe test.
Fighting robots are inherently dangerous. Safety is paramount. We require that all competitors abide by all the safety rules for their weight class. This is not just for your safety but everyone else's as well. Safety violations can occur for:
- Improper or non-use of weapon lock
- Unsafe weapon tests with box open
- Unsafe touching of the bot (grabbing an unlocked weapon)
- Improper load-in procedure
- Pit safety issues such as open test box testing, driving in pits, weapon test on table, etc
We will use an escalating system of consequences: These reset each event.
- 🟨 1st issue: Yellow Card: Warning
- 🟧 2nd issue: Orange Card: Match forfeit
- 🟥 3rd issue: Red Card: Event forfeit
- ⬛️ 4th issue: Black Card: Year forfeit
Each of these levels comes with a chat about what happened and how to improve safety. We 100% understand that accidents happen, especially under stress. If you get a card, please don't panic. It's not a sleight on you personally. We will do everything that we possibly can to make sure that we work together to correct the safety issues in question. As a competitor myself, the absolute last thing I want to do is tell a competitor they can't compete. However, if said competitor is putting themself or others in danger, we need to make sure those issues are corrected.
A weapon lock is anything that will keep your weapon from being dangerous when your robot is not in the ring. Weapon locks are required during loading and unloading into the ring or test boxes. Robots that don't use a weapon lock are a hazard to everyone at NHRL and are not allowed. Failure to follow rules will result in a verbal warning and a second failure will result in your robot being disqualified from the event for the day. If you have questions don't hesitate to ask the staff. Everyone is friendly and supportive, safety is just very important.
When must a weapon lock be used
- During robot load-in to the cage or test box
- Anytime your robot is powered up anywhere at NHRL
What works well as a weapon lock
- A metal pin or plug that prevents any rotating weapon from spinning, ideally painted a bright color.
- A plastic cover (pool noodles work well) over any sharp blade on your robot
What isn't great as a weapon lock
- Anything that can easily fall out or be dislodged
- Your hand or any other part of your body
- Using a tool such a vice grip is frowned upon as a weapon lock.
- Weapon locks should be a dedicated item and not something that could be confused in any way.
- If you drop your bot, a vice grip may disengage from the weapon. A dedicated weapon lock should not.
- A vice grip requires two hands to engage and disengage. A dedicated weapon lock should not.
Testing your Robot
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 and/or minibots 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. The station is conveniently located by the load-in dock, en-route between the pits and cages. It’s marked with appropriate signage and is blocked off by black and yellow stanchions. Failure to use the hazard station appropriately may result in a penalty via the safety demerit system.
The Robot Hazard Station is designed and equipped for two purposes:
- Firstly, it provides a designated location for builders of robots with flamethrowers, pneumatics, hydraulics, internal combustion engines, jets, rocket engines, ramset charges or airbags to safely load, fill, pressurize and depressurize their systems. Robots fitting into one of the listed archetypes MUST perform tasks here. Certain exceptions may be made depending on the weapon type and materials used.
- Additionally, it serves as designated post-fire robot inspection and clean-up station in the event that a robot is rushed out of the building after a match.
Hazard Station Rules:
- No more than 3 teams with 2 representatives each may work in the station at a time.
- Use appropriate PPE when working in the station.
- Return all tools to the cart/cabinet.
- Clean any spills or messes created while working.
- Do not charge batteries in the Hazard Station.
- If recovering from a fire, talk to the hazard station attendant for a check-in
- If you have any questions about the robot hazard station, hazardous robot types or best practices, please reach out to us.
Batteries, if mishandled or damage, present a fire hazard. Please be sure to inspect your batteries thoroughly before each use;
Signs that a battery has reached the end of its life:
- Any battery that has sustained damage or cuts to the metal foil that holds the cells.
- Puffy batteries. Batteries that are starting to fail will start to fill with hydrogen gas. This will make the battery puffy. A little puffy is likely OK for a few more matches.. but a very puffy battery is no longer safe
- Batteries which cannot be charged. If the charger rejects the battery due to bad cell voltage its not longer safe
- Batteries with bare balance leads or bare leads are a short circuit risk. Short Circuit = FIRE. Fix or dispose of right away.
- Batteries that have become too hot to touch are no longer safe
Even batteries that appear perfectly healthy can change at a moment's notice. It is important to monitor batteries while they are charging, and if possible use a LiPo bag to contain batteries as they charge.
NHRL has a number of battery disposal bins around the facility where you can surrender damaged LiPos safely.
If you do not feel safe handling a damaged battery, find a member of staff to assist you.
Fire and Flame-Based Weapons
NOTE: We may or may not be allowed to run flame-based weapons at our June event. We will know more closer to the event.
Fire-based active weapons are allowed at NHRL, with the following stipulations...
- Weapons which use fire or heat must be able to self light, and self extinguish.
- They should also self extinguish in the event that the connection to the transmitter is lost.
- A weapon is also considering self extinguishing if it flames out after 30 seconds from ignition
- Competitors must demonstrate for safety the appropriate respect and precautions when working with flame or heat based weapons.
As of March 18, 2023, bots at NHRL are limited in the mass of flammable gas that can be carried. Bots in the 3lb category are limited to 8 ounces of fuel. Bots in the 12lb and 30lb categories can carry up to 16 ounces of fuel.
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 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
In addition, 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. This would include standard camp-stove style canister hoses.
Matches may be stopped and your bot disqualified if cage equipment, including cameras or safety gear, is being damaged by fire.
Rocket Motors and Fireworks
Rocket motors and fireworks are not allowed at NHRL as of the May 2023 event.
Cage Load-in/Load Out Procedure
Please see the Cage Load-In and Load-Out for details on our cage load-in and load-out procedure.
We serve adult beverages on the premises at NHRL events. However, alcohol does not mix well with power tools and combat robots!
Builders are not allowed to drink alcohol as long as they have a robot they are working on active in the competition, or planning to fight in a grudge match.
Builders whose bots are no longer in the competition, not fighting any grudge matches, and who are 21 years of age or older, are allowed to drink alcohol.
Note that inebriated builders who are causing a disturbance will be asked to leave, even if they are no longer in the competition. Please drink responsibly!
All new rules for 2023 will show up in this color.
This criteria covers judging for head-to-head matches for full-combat bots. NHRL only runs fights with 3 or more bots as exhibitions, so we do not require strict judging criteria there.
If a fight does not end in a knockout or a tapout, the winner is determined by a panel of 3 judges, although we may occasionally use a single judge if circumstances force us to. If the match referee ends the fight early (if both bots are simultaneously incapacitated, both bots are so stuck together that the match can’t continue, or for other similar reasons), the judges will determine the winner of the match as if it had gone the full time.
Each judge rates the competitors across 3 categories: Aggression, Control and Damage. A judge allocates 6 points to the competitors each for 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.
All judges' decisions are final.
For example, consider a match between bots Foo and Bar that goes to a panel of 3 judges:
|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 is the intensity and frequency of intentional attacks, preferably with an active weapon. To score points here, you need to make attacks that could conceivably affect your opponent.
The key to aggression is attacking intensely and/or frequently with an active weapon, and an intention to affect your opponent.
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 fewer aggression points. For example, ramming an opponent with a disabled beater bar should score fewer aggression points than if the beater bar was working.
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 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 hit each other with their active weapons simultaneously and one gets sent in the air, both are showing equal aggression.
If a bot declines to engage its opponent, or is technically unable to engage for a significant period of time, it should lose aggression points. 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.
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.
Bots do not get aggression points for interfering with the house bot.
A bot may gain or lose up to 1 aggression point for actions performed by its minibot(s), whether they put themselves in harm's way to affect the fight, or they spend the fight avoiding contact or not moving at all.
(EXCEPTION: For sportsman fights in our March and April 2022 events, we are allowing bots without active weapons. So for these fights only, we will consider attacks with passive weapons on par with attacks from active weapons. Starting in May 2022, sportsmen will be required to have active weapons, and will be judged the same way as full-combat bots.)
Aggression judging matrix
- 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.
- 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 never used its active weapon to attack its opponent.
- The opponent spent a significant portion of the match actively avoiding engagement.
- 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 is how well you dictate the flow of the match. To score points here, you want to put your opponent in a bad spot, like pinning them or getting them stuck.
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.
If a bot sticks itself, that counts as if it was stuck by its opponent (although see the tiebreaker rule below).
A brief period of being stuck (e.g. getting a fork stuck in a divot for a second or two) should not count against a bot for control. A bot should be stuck long enough to affect the flow of a match in order to lose control points.
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.
Bots do not get control points for interfering with the house bot.
A bot may gain or lose up to 1 control point for actions performed by its minibot(s), whether they stick their opponent or get stuck by their opponent.
If bots seem to control the match equally, shift your focus to each driver’s control of their bot as a tiebreaker. Was a 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.
Control judging matrix
- 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.
- 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.
- 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.
- Both bots seemed to control the match equally.
- Neither bot seemed to take control of the match.
Damage is the condition of your opponent’s bot at the end of a match compared to how it started. To score points here, you need to hurt your opponent’s critical systems.
Damage is the relative state of the bot at the end of a match, as compared to at the start of the match, with its weapon and drive systems assumed to be fully functional 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 (Level 1), and least is at the bottom (Level 6).
- Level 1: Destroying or disabling the drive system and all weapon systems on its opponent will score maximum damage points. In this case, the opponent was likely only saved from a knockout by the fight timer running out.
- Level 2: Destroying or disabling some of an opponent’s drive or all its weapon systems. 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. It also means disabling an opponent’s drive to the point where they can translate around the arena just enough to avoid being counted out, but not so much that they can move anywhere at will.
- Level 3: Reducing the effectiveness of an opponent’s drive or weapon systems. This includes removing at least one wheel, doing enough damage to at least one wheel to make it inoperable in a way that significantly affects the bot’s driving, partially disabling an articulated weapon (disabling either the saw or the arm, but not both), or cutting a flamethrower line so that the other bot sprays fire on itself. It also includes compromising an opponent’s ability to drive somewhat, but not enough to initiate a count-out.
- Level 4: Doing structural damage to an opponent, like damaging its frame, doing significant damage to non-ablative armor, or damaging a wheel in a way that doesn’t significantly change a bot’s mobility.
- Level 5: Most ablative armor removed from at least one side of the opponent, or small gouges/holes in an opponent’s non-ablative armor.
- Level 6: Cosmetic damage to a bot, like scratches against paint. Or, some ablative armor removed.
Ablative armor is any non-structural component intended solely to absorb damage by being consumed.
Running out of fuel (i.e. flamethrower fuel, power from a weapons battery, pneumatic gas) does not count as damage, even though it would disable a weapon.
If a minibot takes more damage than its opponent’s minibot, or if only one bot brings a minibot that takes Level 3 or worse damage, the bot with the minibot should take up to two levels of damage more than it normally would. For example, if a bot finished a match at Level 4, but its minibot was completely destroyed, it should be considered at Level 2.
For multibots of roughly-equal size, average out the difference of damage levels between the multibots, rounding towards a higher damage level. For example, if one half of a multibot finished at Level 4 and the other half finished at Level 1, consider the bot at Level 2.
Judges may request that cage managers show damage to a bot on the livestream. This may not always be possible, but when it is, the cage manager should honor it. Judges should only make this request if they absolutely need it, as it does take up time.
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’s ablative armor or other removed material. In that case, damage is not counted against it.
Damage judging matrix
- There are at least 4 levels separating the two bots. For example, one bot is at Level 6, and the other bot is at Level 2.
- There are 3 levels separating the two bots. For example, one bot is at Level 4, and the other bot is at Level 1.
- There are no more than 2 levels separating the two bots. For example, one bot is at Level 5, and the other bot is at Level 6.
- Both bots did an equal amount of damage to each other.
- Neither bot did any damage to the other.