FIRST Robotics Competition Blog

Motor Rule Changes for the 2024 Season

Aug 22, 2023 Written by Jay O’Donnell, FIRST Robotics Competition Mechanical Engineer




On behalf of the FIRST® Robotics Competition game design team, I’m writing to share a change coming to the robot rules for the 2024 season. We are sharing this now to help teams and vendors make better informed decisions as they prepare for Kickoff.

For the 2024 season, teams will be limited to four motors that enable the robot to move around the field, which we are calling propulsion motors. This rule will not apply to motors that generate small amounts of thrust as a secondary or incidental feature, which include but are not limited to:

  • Motors that alter the alignment of a wheel in contact with the field surface (such as a swerve steering motor),
  • Motors that run game piece intake wheels that happen to contact the carpet, and
  • Motors that change the speed of the drive wheels using a shifting mechanism without significantly contributing to propulsion.

We felt this change was necessary for a few reasons:

  • Robot to robot impacts from very fast robots can often lead to a variety of what we call “feels bad” moments, such as robots getting tipped or breaking from quick interactions that have little driver influence. This is a problem both for teams affected by the impact and volunteer referees having to make tough calls that may decide the outcome of the match.
  • The potential for field damage from very fast robots is problematic for keeping the field running both during an event, and at future events where the field will be used. High energy impacts can also cause field elements to move or the field carpet to stretch, which makes it difficult to maintain consistent playing field dimensions.
  • We think this change is another step to give teams a more equal opportunity when faced with financial or supply chain constraints.

This is not a decision that the game design team takes lightly because we aspire to keep the robot design space as open as possible. While many 2023 robots would have been unaffected by this rule change, we anticipate that the frequency and severity of the high impact collisions described above would increase as more designs transition to using more than four propulsion motors.

This solution is one of many discussed; both among the game design team, and among a team of experienced community members. We invited the team of community members to work on recommendations in parallel, and their work converged in this direction too.

The exact wording of this rule will be released at Kickoff. We wanted to share the core function of this rule change as soon as possible, while still giving ourselves time to work through details and exact phrasing.

We recognize that this rule change will not always solve the challenges addressed above, and we will continue to evaluate this solution and other potential solutions for 2025 and beyond. We look forward to seeing what you bring to the field in 2024!

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My team has run 6-motor tank drives the last two seasons. It's a relatively cheap upgrade over the stock AM14U5 chassis (roughly $400 for everything--plates, motors, controllers), and it's felt like one of the few ways for a mid-budget team to physically keep pace with teams dropping thousands more on swerve drive systems.

While I understand the need to keep the highest-end teams in check because 8-propulsion-motor swerve was about to hit like a tsunami, this phrasing feels like it's going to drive an even bigger competitive gulf between teams who have resources to swerve and teams who do not. I'm not a fan of that.

Since I was trained to not complain unless proposing an alternative, here’s mine: if you make X weight, you get another two motors.

Hi Billfred,
We understand your concern, as trying to keep FIRST Robotics Competition an equitable experience for all teams is one of our goals. Please keep in mind that this rule change was not just made with an 8-propulsion motor swerve in mind, but all drivetrain styles. A 6 propulsion motor tank drive and a 6 propulsion motor swerve can create the same kinetic energy.

We appreciate that you are offering another solution and we will consider it as we explore options for 2025 and beyond.

How would this rule change affect differential swerve which uses both motors as steering and power motors?

Hi Quinn,
A differential swerve module that uses both motors for steering and propulsion would be considered to have two propulsion motors in it.

Does this preclude something like the holonomic H drive system we've been developing? (four motors driving forward and back, two motors in the H module for lateral motion) That would be very unfortunate, as we've been developing this as a more affordable way to compete in the age of swerve

Hi Clint,

This rule does not prohibit any style of drive system, just the amount of motors. In the specific case you mentioned, there are six propulsion motors which will not be allowed with this rule change for 2024. There are a number of ways you can still use this style of drivetrain without using more than four propulsion motors.

If very fast robots is the problem; how about limiting robot speeds? Or, peek drive current? This rule changes eliminates at least one class of drive currently used. Four corner (or tripod) differential swerve. And limits potential H-drive configurations. Or, limit the long open field runs available. Charged Up was designed for max speed collisions at center field. 

Hi Stephen,
We appreciate you looking at this as a problem statement and trying to come up with solutions. The FIRST Robotics Competition game design team as well as a team of experienced community members discussed many options to limit robot speed in other ways, and there were pros and cons to all options. The solution we’ve chosen for the 2024 season was the option that we felt best addresses the challenges stated in the blog, as well as being the easiest for teams to understand and design for and for volunteer inspectors and referees to check at events.

Like we said in the blog, we recognize that this rule change will not always solve the problems we are trying to address, and we will continue to evaluate this solution and others for 2025 and beyond.

Will differential swerve be permitted? Once the direction is established a differential swerve could be considered 8 motors driving the robot.

Hi Steve,
Please see my response to Quinn’s question above. Thank you!

limiting the number of motors doesn't seem as useful as limiting the top speed of the robots (during inspection, stick them on a treadmill and run them at their full speed, or present engineering specs that prove the top speed is less than the determined limit)

our current SDS swerve modules do 16ft/s, one of our competitors redesigned theirs to use belts rather than gears and claims they can get up to 26ft/s; we both use the same 4 motors...

Hi Ross,
Please see my response to Stephen above regarding the idea of limiting robot speed in other ways. We discussed ideas very similar to the ones you have provided.

Limiting the number of motors doesn’t necessarily limit your top speed, but it does limit your total motor power available, and therefore your acceleration. You can certainly adjust the gear ratios of a COTS swerve module to get a different top speed, but it will probably take you more time to get up to that top speed.

This rules out the possibility of differential swerve systems, correct?

Hi Marty,

Please see my response to Quinn’s question above. Thank you!

למה לא בסוף העונה יש קבוצות שכבר תכננו את העונה הבאה עם מספר המנועים

Hi Ofir,
Apologies if I have translated your question incorrectly, but I have translated it to: “Why not at the end of the season there are teams that have already planned the next season with the number of engines”. This is a great question. We started discussing this topic soon after the 2023 FIRST Championship and wanted to take an appropriate amount of time to explore different options to ensure we felt confident in the direction we have selected.

How will this ruling affect differential swerve modules Many of the modern serve modules use differentials between two motors to control direction. With 2 motors required per corner for this does this rule make 90% of current swerve modules illegal. Considering the cost of new modules will allowances be made for these existing modules.

 Hi Joel,
Please see my response to Quinn above about differential swerve modules. The majority of the swerve modules currently available from various FIRST Robotics Competition suppliers are not differential swerve modules; they use one motor for propulsion and one motor for steering. Therefore, you can run up to four of these swerve modules and still be compliant with the new rule.

Our current KOP tank drive has two drive motors on the left and two on the right powering just the center wheel.  So that would not be legal and we would have to remove one motor?

Based on your description you have four propulsion motors in your drivetrain, which does not violate the new rule, as you are allowed up to four.

Hey! I just wanted a clearer definition of what 'secondary and incidental feature' would mean? Our team is confused on the difference between swerve steering motor and what was mentioned in the comment by Quinn:

How would this rule change affect differential swerve which uses both motors as steering and power motors?

Hi Quinn,
A differential swerve module that uses both motors for steering and propulsion would be considered to have two propulsion motors in it.


Hi John, 

The exact wording of the rule will be released in the manual at Kickoff. Many teams that have swerve use modules where 1 motor controls the propulsion and 1 controls the steering. Alternatively, there is another type called "Differential Swerve" where both motors control propulsion and steering.

What about a game like Deep Space where many teams used a supplemental propulsion mechanism to move their bot forward when trying to climb to higher levels of the habitat? While this could be viewed as exceeding the number of motors if four are already used for the main drive on the field, use of an additional motor in this way seems in the spirit of the new rule. Thoughts?

Hi Bill,

Great question! This is a topic that we are continuing to discuss while preparing the manual for kickoff. 

Would these rules apply to endgame mechanisms with powered wheels/treads such as many habitat climbs in 2019 and a few charge station side climbs in 2023? I am not completely sure if that would fall under "small amounts of thrust as a secondary or incidental feature" or if endgame climbs would not be allowed to have powered wheels which touch the field from now on. Thanks!

Hi Kaushik,

Great question! Please see my response to Bill above. Thanks!

In the 22 season we built a working switchable gearbox - essentially a transmission where 3 motors worked towards driving and a servo flopped the gearing to use for climbing using the same motors. Can we do 2 driving and 3 climbing for example in the same gearbox - provided we can prove that only 2 are driving per side? This transmission was CAD'd by a freshman who only learned Solidworks the fall of 2021 and designed and built it with guidance only from our engineering mentor. She learned Solidworks from another student. Ultimately we went for a different climber approach but the transmission functioned great the whole season in 3D printed form with metal gears. I would hate to see that kind of innovation be stifled though this rule just means we have to be more innovative to solve problems of power vs speed.  

If it is only mechanically possible for a maximum of 4 motors to be “propulsion” motors as described above, additional motors in the same “gearbox” would be permitted. Software limits are unlikely to be sufficient based on current wording. As with other robot rules where it is possible for the robot to break the rule, but the robot is restricted from doing so via mechanical stops, it will be up to the team to clearly demonstrate to the Inspectors that the robot complies with the rules. For examples, please see R105 and I106 from the 2023 game manual.

Every season the game is ultimately about how many different (and repetitive) tasks can be done within the window of the match. It possible the game designers did not have the time to consider the effect on the game cycles that slow robots on the field would have to contend with. Has the rules and game play taken into account the 4 max drive train rule change?

Hi Jay - Yes, the game design team has reviewed the 2024 game with respect to the new drive train rule. Thank you! -Collin

Hi I just wanted to check if these are illegal these are the swerves mk4


Hi Peter,

Swerve modules like the MK4 use one motor for propulsion and one motor for steering. The steering motor does not count as a propulsion motor.

I find this is a good solution to help limit impact related damages that affects teams with lower budget. The price of these 3 motor swerve and replacement motor is also hard to sustain, especially for the championship. Good idea!

Does propulsion motors refer to the possible motors that could "touch" the ground during a match or the amount of motors that "touch" the game at any given time? To clarify, if there are smaller wheels that are in the center edges of the robot that only contact the ground when the robot is high-centered/ the front or back two wheels are not touching the ground in that instance. This assumes four motors in each corner for four wheels and two motors for the center edge wheels that only touch the ground when two of the main wheels aren't touching the ground. If this is illegal then it feels very limited in terms of drive architecture for a game with terrain field elements.




Hi Jackson,

Great Question. The intent of the rule is that only 4 motors are providing propulsion to the robot throughout the match. If 4 motors provide propulsion during part of the match, and another 4 provide propulsion during another part of the match, that would be 8 motors providing propulsion during the match.

As always, check out the 2024 game manual after kickoff to confirm the final wording of this rule.

Does the definition of propulsion motor refer to the motor's size and strength or the use of the motor. For instance, if we use brushless NEO's for both driving and steering our swerve drive, but the steering motor is amped down through the power distribution hub, would they both be considered propulsion motors. I believe this is the case, as the motor would not be capable of giving as large of thrust as the motor that drives the wheels.


The definition of propulsion motor refers to the motor's usage. If it is only being used to steer a drive wheel and not power driving, it is not a propulsion motor. The type of motor or its power output do not matter for defining if it is a propulsion motor. Please check the 2024 game manual for the final wording of this rule.

Good luck this season!

So does this mean that the REV Swerve is legal?

Hi Joshua,

Swerve modules like the Rev MAXSwerve use one motor for propulsion and one motor for steering. The steering motor does not count as a propulsion motor, so you can use four of these modules in a drivetrain.

Good luck this season!

In previous years we have seen so many types of driving styles, each with its unique features and characteristics.  The abundance of chassis designs is one of the reasons why we love FRC.  So I am deeply concerned that this new rule will eliminate any possible chassis innovation and limit the drive-train solution down to one: swerve drive.
Yes, technically, the rule did not prohibit any chassis design.  But the rule has made it almost impossible for teams to think about any chassis types other than a swerve. The primary advantage of innovative drive-trains we've seen today is that they implemented some kind of mechanism, like the mecanum wheel, that allows each motor to both provide propulsion for the chassis and control the direction of movement. This saves the team from using extra motors to control the direction and allows the team to more thrust.  But now that the amount of propulsive motors is limited, it makes swerve drive literally THE INVINCIBLE CHASSIS. 

A more significant and appropriate action, in my opinion, will be to limit the total power of the robot. According to the law of physics, that is the most straightforward way to limit momentum(power = force*velocity, momentum = mass*velocity), and it encourages teams to seek for more efficient driving style. It is very easy to achieve too, just apply a power limit to the PDP in its firmware.

You commented regarding a holonomic H-drive system; however, I still have the following question because any h-drive limited by your answer would by at a significant disadvantage to teams already possessing, or with the resources to acquire, swerves drive capability. Moreovrer, it also may promote the use of holononic mecanum-drive system which may be harder on the feild carpet than other drive systems and  have an even greater power propulsion disadvantage to swerve drive systems because of shear forces and power lost due to opposing drive vectors. Therefore, my question/thought is this:

Since it would not violate the spirit of purpose of the rule because speed is always limited to four or less motors causing propulsion at any moment in time, and the other wheels roll with insignificant sheer forces on the field carpet would it be reasonable to permitted, via the rule, the use an H-drive propulsion configuration with four forward/backward propulsion omni-wheels and two right/left drive omni-wheels if proving to be limited by programming that allows only the forward/backward propulsion omni-wheels or the two right/left propulsion omni-wheels to propel the robot at any moment of movement?


It is realized that this would create some additional efforts on the part of inspectors during inspection of robots that would use such a transport/propulsion system, yet this overhead should not be excessive.


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