Soccer Entry Light Weight and Entry Standard Kit 2024 update #soccer-entry-rules-2024

RoboCupJunior Soccer
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Hello everybody,

we haven’t yet spent a lot of thought on the evolution of the Entry rule sets. We’d like to hear your ideas.

Especially if you are a mentor, team or regional representative from a region running any form of Entry (either the rules the committee has provided or other rule sets - we’re very interested to learn and adapt aspects from the regions).

I will collect links so separate per-suggestion-threads in this post so you can stay up to date if you follow this thread using the little bell symbol.

Best Regards
David

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Hi David,
thanks for starting this topic.

I see a large skill - difference between Entry Standard Kit and Entry Light Weight as it is intended at the moment. In fact, countries like Croatia already do not stick to the Standard Kit rules anyway as they allow some extra sensors an port multiplexer and glue at the standard kit competitions.
Keeping in mind that with the end of the LEGO Mindstorm kits the allowed sensors are hardly available anymore this is a way other countries could follow.
So I would love to open this league in the following way:

The Italians do this for quite a while and would love to see their well thought rules as a European agreement as far as I know.

The Idea is to open the Entry league for all material but reduce the number of drive motors to 2.
This would mean there are no omniwheels at all and the robots “behave” like “normal” Lego robots, no matter which material is used.
That would offer a robocup - start with LEGO or other “toys” and then improve to whatever is wanted without designing an omniwheel lightweight robot.

It could still be a subject of discussion how many actors are allowed in total so that we could use kickers and/or dribblers even in this league.

The next step for the kids to go would be the 1vs1 lightweight league.
There the kids could start (and win) with an omniwheel LEGO robot, if they want to stick to their LEGO kits for longer.

This again is a good skill-step towards 2vs2 lightweight.

I would absolutely love to take part at the “new” entry league in 2024 as I have lost of kids wanting to play soccer that are not experienced enough to build lightweight omniwheel robots but do not want to “play with LEGO”.

What do you think?

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@remosgro could you report some experiences from that league? Particularly what aspects of robot design and strategy get emphasized more and less and what aspects require significant adjustments for going to 2v2 leagues? We hoped building 1 LWL bot for 1v1 would make it significantly easier (both in effort and financially) to switch from 1v1 to 2v2.

Over a number of years I’d imagine some schools/clubs would hone in on that spec as well - but no solution lasts forever. We agree that we need 1v1 to not have robots previously used in 2v2 in it.

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Yes sure, here I’m.
As mentioned by Stiebel, in Italy, we had our own soccer entry rules, which we also utilized in the EURCJ 2018 competition.

http://2018.robocupjunior.eu/wp-content/uploads/2018/02/SuperLight-EN.pdf

We used similar rules until last year, at which point we adopted international regulations. This shift occurred because the Italian team selected last year encountered significant challenges due to the differences between national and international rules.

I believe it’s important to have standardized rules for all countries, even within entry-level leagues.

I was initially uncertain about the brand obligation. However, in Italy, we had more Lego-entry teams than Light-Entry teams (while in the European championship the numbers were similar). Starting with Lego is easier, but it’s also true that the availability of Lego sensors is decreasing.

I think that LightEntry is a god idea, a little step toward official leagues, but I also see some problem coming from the past. In the official leagues there introduced was a lot of rules in order to discourage brutal force game, but in the Entry Light i sow this year that this problem is back.

I think we require technical limitations to promote strategic gameplay. One potential solution is imposing restrictions on the number of motors (like old Italian rules), but we could also consider limitations on motor torque, or other form of limitations.

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Hi Raimondo,
thanks for your post.

The 1-page rule-set shows, how easy things could be…

However, inspired by your rules of 2 traction motors and your experience with that I would like to officially ask for this rule (max 2 traction motors) to become part of the “entry” leage combined with opening this leage to arduino (or other) based DIY Robots. I would be fine with 8V (7.2 nominal) but I think we need 9V to allow 6xAA Batteries in Lego robots.

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Just for clarification: the two motor suggestion is for soccer entry and not lightweight Entry leauge right?

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Yes, I would like to “open” the standard league to open platforms as you cannot buy Lego EV3 and sensors anymore as new parts. And to keep the level low we have to reduce the technological possibilities. Learning from Italy shows that 2 drive motors seems to be a good choice.

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So, there will be no more entry league for lightweight? Just the normal soccer entry league with and adapted ruleset.

If so, I have a few concerns:
First of all, schools who only have Lego will be annihilated by all the schools using electronic kits. Consequential, thousands of euros/dollars in Lego are practically waste (Yes, we know about the entry leagues in rescue. But schools without a rescue arena have no realistic chance to keep their students interested in the rcj).
And with no entry league for lightweight, new teams have no possibility to get “warm” with the use of electronic and omnidirectional robots.

I see the point of allowing other parts than Lego in the future, but not now.

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Hi Elias,
no, I think you misunderstood.

I would love to see both 1vs1 leagues like we had in 2023.
I simply want to open the lowest league to “non-standard” kits as well.
And to keep the level low I suggest the Italien 2drive motor rule.

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Hi stiebel,

sorry, I misunderstood.
With this background I fully agree with a limit of two motors for driving.
Changing the allowed materials is in my opinion something for next year, so Lego only school have some time to adapt.

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Hello everyone,

I completely agree with limiting the number of motors in the standard kit category, and I believe that introducing such a rule would turn that league into what it actually is – a developmental league for new teams. I think the ideal solution for these leagues would be to restrict the number of motors to 2 in the Standard kit category and 3 in the Lightweight Entry category (excluding kickers and dribblers).

In the LightWeight Entry category, we encountered a significant issue this year where robots mostly focused on power, which caused quite a few problems during the competition. Unfortunately, we even lost 2 Lightweight balls due to the force of impacts against the wall. There was also a lot of damage to the surface. Therefore, I would agree with a rule change to reduce the damage. This could mean either limiting the motor power (which could be harder to control) or even reducing the number in that category, limiting it to a maximum of three motors. Additionally, to decrease field damage, I would suggest another rule where all wheels must be made of a type of plastic that doesn’t harm the field – perhaps extending this rule to entire robot chassis to preserve the field walls as well.

I would also like to say that the rules used in the standard kit category at the European competition (https://rcjcroatia2023.eu/files/RoboCupJunior-Soccer-Entry-Rules-2023.pdf) were adhered to by all teams. As for the Croatian team, I got in touch with them; they had an external ball-tracking sensor, which is permitted by the rules. As far as I know, this sensor is available for purchase in the same form it was used in the competition. If I’m not mistaken, the team was compelled to acquire an external ball sensor because Fischertechnik kits do not include their own ball detection sensor. Regarding other components, all parts are from the Fischertechnik set. The team that competed this year didn’t use glue; it was the team that competed in Portugal who used it. Also is there a rule about the ban on glue usage, or am I mistaken? In Croatia, such a rule doesn’t exist. As far as I know, the Croatian robot was in compliance with all the rules, just like all the other robots at the European competition.

Regards,
Ivan Kolarić.

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Hi everyone who is following this thread, we’re having an open committee meeting on the topic of entry on Sep. 6th, see Soccer Rules Open Meetings #soccer-rules-2024

We will post stuff talked about on the call back to the forum because we know not everybody will be able to make it to the meeting and please do continue discussing here, there have been a lot of good ideas already.

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Hi Ivan,
sorry, if my comment hurt you, I did not want to say “the bad Croatians did it” but in fact “the Croations did, what we all should allow”.
Sorry for the “glue” missunderstanding. I actually only know about the team in Portugal, that is right.
In Germany we used to have a “whitelist” of allowed sensors for standard in the past and we simply want to use the extended sensors as well.

However your point of to much speed and power in 1vs1 lightweight is something I totally agree.
If we start with 2 drive motors in entry, allow only 3 drive motors (and omniwheels) in 1vs1 lightweight and than open it to whatever is wanted in 2vs2 IR-Leage (formally known as lightweight, but without the lightweight-part) we could have a smooth climax from entry to expert.

So I would love to see this in the rules whenever possible.

Thanks for this suggestion, I think this could be the “missing link” between the leagues.

Best regards,
Roland

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Here are the notes from today’s (9/6) meeting for those that missed it. Thanks to all those who attended. Please feel free to post if there is anything left out.

Issue: gap between building Lego/FischerTechnik robot and going into Entry LW

  • EV3 discontinued and no plans for official IR seeker for Spike
  • Different regions have different limitations (e.g. no glue, no port multiplexers). Regions have these limitations to make the competition more equal amongst the technologies easily available. Although opening up the rules to everything seems like a good idea, there should be a balance of limitations so that teams cannot take advantage with more advanced hardware than what most are using. Counterpoint that some of the standard parts (e.g. HiTechnic IR Seeker) are no longer available.
  • Suggestion from forum to adopt italian SuperLight rules:
    • Max 2 wheels/drive motors
    • max 9V (to allow AA batteries although most teams will use 2S lipos)
    • no specific brand of parts

Discussion to limit the torque of the motor based upon motor documentation. Counterpoint made that it will be difficult to verify during competition and if we open the rules we want to limit the discussions at competitions. Rebuttal that a 9V motor ran at 12V will run at the same torque since it will draw less current. Point made that torque restrictions may not easily be understood by young participants and we should stick to easily recognizable motors that are easy to verify. Lego Spike motors can easily have wires stripped to get access to control motors w/ open platform. Search ensued that discussed the many varieties of Lego motors especially the old Lego RC motors which are more powerful than what typically comes in a kit; suggestion to make a detailed list of acceptable motors. Suggestion to base it on the diameter of the motor.

Representative from Italy discussed what they experienced with having open solutions in the entry league and did have a mixture of Lego and other motors. Suggestion to measure torque. The open teams were better than the Lego teams. Suggestion to have two entry leagues.

Suggestion to have robots sumo each other for inspection. Using a datasheet was brought up again - suggestion to make the torque rules for non-kit motors to be lower than expected since datasheets often overestimate values and this would make those choosing an open set of motors to have a slight disadvantage. Clarification made that we’re talking about the final output torque specification including any gear boxes. Point made that this means it will limit teams bringing custom gear boxes. Conclusion to just restrict it to a standard list of components especially since it will be hard for newcomers to adhere/understand/want to follow the rules even if different regions may have different lists.

Question about restricting weight to 800g with 9V AA batteries makes it very difficult. Point made to make a limit up to 1100g is better even though making it lighter will help limit power. Upper limit should be what a typical kit robot weighs so an open robot would not have the advantage of being heavier. Of course, kit bots could also just add weight.

Clarification made to restrictions will be for only driving wheels or wheels that have traction. Casters or wheels that coast will not count towards the limit.

Any potential restrictions on kickers and dribblers on open platform entry robots can be discussed for future seasons if they become an issue.

Entry LW ideas to reduce old 2v2 bots in the league

  • No restriction on wheels b/c metal wheels may have plastic wheels and we can just DQ any teams that damage the carpet.
  • Restrict to 3 wheel robots.
  • Keep 1100g limit.
  • Keep 12V

Comment made that reducing the number of motors is a good thing since standard LWL bots cannot be recycled down. Agreements made that above proposed rule changes make a good progression from entry 1v1, entry 2v2, and LWL.

Comment made that the micro metal gearmotors will burn out easily if stalled/won’t work very well so suggestion to include larger gearhead motors on the whitelist that are more reliable and comparable to kit motors. Plans to discuss the final motor whitelist on the forum.

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Hi Mike, thank you for this summery.

It looks like the 2. league, the 1vs1 lightweight is sorted out and we could see these rule changes as settled. So we have to talk about the entry (former standard) league.

I would like to start the discussion about the motors.

I think a real “whitelist” is hardly possible for worldwide use as there are similar motors or even same motors with different brands. And to make it harder there are motors looking the same with completely different specs.
On of the resellers with a large variate of available motors is Pololu, but I am not sure if they possibly do buy there motors in China and the Asian market hat the same motors with just other names or product numbers.

So I would like to establish a rule that can be checked by easy measurement.
as rotations per minute and torque can be interchanged just by gear ratio the measurement of the consumed power sounds much more reasonable to me.

As we plan to reduce the maximum Voltage to 9V or practically 2S Lipo, that is slightly more then 8V with fully charged batteries, we can assume that all teams will have this very voltage for their motors.
So testing the stall power is easily measured by the stall current.

We had a 12V-2A power limit per motor at the former 1vs1 open rules in Germany (? or elsewhere) to avoid these wonderfull Pololu 25D12VHP motors with their 5A stall current consuming 60Watt per Motor.

The 12V-2A rule lead to a motor that fitted perfectly, and this is the Pololu 25D12VMP motor.
Combined with a 9.7:1 gear this motor is probably the most used motor in Germans soccer 1vs1 and as far as I could see the other European teams use this motor as well.
This is the link: Pololu - 9.7:1 Metal Gearmotor 25Dx48L mm MP 12V

So this motors are lying around in classrooms and garages already.
And they are affordable and very robust.
So why am I talking about this very motor?
Well, using this motor with only 8V will bring the stall current down to 1.2A
and this will reduce the maximum power to 10W.
This is roughly the power of large Lego Motors as far as I know.

The great advantage of allowing this type of motors is that they can be (re-) used for the next league as well, as they have have more than double the power at 12V. And this is probably a great sign of sustainability.

So my suggestion is not a whitelist but a stall current limit.
Make it 1.2A, 1.3A or even 1.5A to make sure there is no surprisingly superior motor within one series.
If a robot behave as expected, the motor datasheet should be fine. And if a robot looks far to powerful, referees should be allowed to measure the stall current at 8V.
If teams know that this could happen, they can be told to be prepared for it and have the ability to unplug the motor and plug it into a testing circuit of the referees. (That is a 2S Lipo and a multi-meter)
(Where “plugging” means connect cables per hand)

Consider this: we are not talking about hundreds of tests but only a few at the whole tournament, if at all.

If we use this current-limitation of 1.2A (or slightly more) we allow a large variety of other motors
but exclude the high current monsters you could get as well.
(like the Pololu - 9.7:1 Metal Gearmotor 25Dx48L mm HP 6V that hat 6A at 6V and 8A at 8V stall current consuming 64W)

We could find any other limit, but my main reason for the 1.2A is the usability of the widely spread 25D12VMP motors of pololu and alike.

What do you think?

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We are not going for worldwide use at the moment - the Americas don’t have a SuperRegional tournament and RCAP doesn’t run an entry league at present.

Given those circumstances for the EMEA SuperRegion downsides remain for the whitelist approach? The reason I am arguing for the whitelist is that it makes it easy for new schools and teams: pick the one from the list that fits best with what you already have/know, no checking of criteria or going on a big search mission. I also don’t think there is much point in using other motors - Pololu, Lego and FischerTechnik are a) already there in many schools, b) cheap enough that finding others doesn’t make a big difference c) hopefully well-matched enough that nobody overruns Lego bots. We can always extend the whitelist when people have something else we can determine to also be reasonable.

So we put it on the whitelist, right?

Maybe we should mention that as a hint to new teams so they can minimize their costs for going to the next league.

But what is the advantage of this over just putting them on the whitelist?

This introduces additional requirements (including particularly LiPo-Safety) for tournament organizers which we try to avoid wherever we can, particularly for Entry.

I would prefer for this preparation not to be necessary.

Unless there are strong reasons to deviate from it I will continue with the whitelist approach for creating the draft version of the rule set.

I don’t think the idea is bad but if we do something like that I’d rather see it in the second league they participate in, not when building their very first robot, frequently with very little assistance.

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Hi David, ok, the point is, we do have this motor anyway and a whitelist with this very motor is ideal for us, but I do not want to be the one creating a whitelist out of our stock…

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So here are the pololu motors that I would like to see on the whitelist:

Pololu - 9.7:1 Metal Gearmotor 25Dx48L mm MP 12V or any other 25Dx48L mm MP 12V motor
and
Pololu - 9.7:1 Metal Gearmotor 25Dx48L mm LP 12V or any other 25Dx48L mm LP 12V motor

Last year I bought a couple of these motors: China 16mm Micro High Torque DC Planetary Gear Motor Manufacturer and Supplier | TT Motor
These are 16mm motors with an excellent planetary gear.
The specs are lower than the pololu 25DMP motors:

grafik
grafik1654×2244 246 KB

The 6V version is rated as a 1W Motor but has a stall current of 1.3A. This is true but it is just producing heat. So if anyone agrees to allow this motor as well, we will have one team using it to check if it is of any good, if not, I am also fine using it at rescue.

Then I would ad any Lego Motor, any Fischertechnik Motor and any surrogate motors for Lego and Fischertechnik.

Is there any more for the whitelist?

If we give a whitelist, we should in fact list motors that are worth using and not “allowed but useless”.
So I would not put any pololu micromotors (overheat) or 20D Motors(gears break due to fast direction changes) or 37D motors (even if the 24V Motor would fit into 10Watts when used with 8V)

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Please add your motors!

I would just like to point out that there is no need to by in the US and pay taxes.
There are European shops selling pololu like https://eckstein-shop.de or https://www.exp-tech.de
and I am sure there are some more.

I just found another one:

This 11,50€ Motor seems to bee between the Pololu MP and the Pololu LP version and is by far the cheapest motor I have found.
If this motor is allowed, I will provide one of my Teams with this motor to check out components for a “bargain”- robot.

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Hi

  1. I have a suggestion for another motor.
    The 12V-2A rule led us to another motor that was also a perfect match and that is the Faulhaber 1741U 012 CXR geared Motor. We have been using this motor for several years and would like to continue using it
    The motor has a nominal voltage of 12V and a connection resistance of 5.8Ohm. A stall current is not defined. At 8V there is a calculated current of 1.38A.
    I suggest putting this moror on the whitelist,
    https://www.faulhaber.com/en/products/series/1741cxr/

  2. I think we need both a whitelist and a defined measuring procedure for approving the Motors The whitelist is ideal for beginners. For advanced users and also for the referees, there must also be a simple measuring procedure in order to qualify other motors.

  3. I would like to point out that a robot with 2 motors has a greater impact on the size of the robot than with 3 or 4 motors. This should be taken into account from the outset if the robots have to be smaller later.

Best regards,
Joachim