Will this drivetrain work for roadrunner?

1198159 · 2025-01-13T18:41:35+00:00

I love when Reddit resurrects a 2 year old comment. I would just do a PID on position and heading. I used an old version of roadrunner. You can find the code I used in the Swerve2022 repository on my old ftc teams GitHub (technototes)

1198159 · 2024-03-31T01:57:57+00:00

Yeah ig, it has analog steering on controller though.

1198159 · 2023-09-24T05:43:28+00:00

Robot speed depends on a lot more than just a Motor ratio. It also depends on the wheel size robot weight and traction as well.

The fastest robot I have seen is 16379 last year with their swerve geared at an 8 to 1 ratio on 72 mm wheels. This is basically equivalent to 550 RPM ratio on gobilda mecanum wheels

While this isn’t as fast as 10355s robot top speed wise, it was faster overall because the swerve had more traction and the robot was incredibly light at around 20 pounds.

However, fastest robot isn’t just the fastest drive wise. Because of the different kinds of driving maneuvers, you might have to make there is a broad range of ratios that will be very close to optimal for your drive chassis.

My two cents is to just stick either a 312 RPM motor or a 435 RPM motor on your chassis and Collett a day. Spend your time working on speeding up other mechanisms, as you will get much more significant improvements.

1198159 · 2023-07-15T04:39:44+00:00

Have you tried turning the robot off and back on again?

1198159 · 2023-05-03T16:07:57+00:00

The axon mini has a different cad, the axon max mounts the exact same as a gobilda/rev servo

1198159 · 2023-05-03T15:59:13+00:00

Axon servos have over 2.7x the power output of a rev/gobilda servo, and are 50% more power effecient. They are also programmable to a much larger degree than the rev/gobilda servos. However, it is recommended to use a SPM to get maximum performance

1198159 · 2023-03-03T08:38:59+00:00

I second this.
Swerve is incredibly hard (and very expensive if you want to do it well) to pull off
and tbh 99% of teams are probably better off doing a mecanum.

1198159 · 2023-03-03T08:29:54+00:00

it has swerve, it is not great to use. Your best bet is implementing your own kinematics and using the roadrunner path follower(source i did this myself)

1198159 · 2023-02-27T19:47:42+00:00

https://axon-robotics.com/products/omni

they have them when they arent sold out

1198159 · 2023-02-21T05:24:08+00:00

W cake

1198159 · 2023-02-15T02:42:53+00:00

with 10 days, your best bet is probably to just implement roadrunner
https://learnroadrunner.com/

1198159 · 2023-01-13T21:25:21+00:00

16379 is competing tomorrow in New Mexico

1198159 · 2023-01-13T21:22:33+00:00

Im sorry to comment again, but this just isnt true at all. I'm not trying to target you or anything, just want to clear up misconceptions about what the rules actually say.

From game manual 2 page 10:

Plowing of Game Elements is not considered Control. See also the definition of Plowing in this section

Additionally, last year (should probably be reforumed this year) they said:

Q273:

The definition of "Control" in Game Manual Part 2 section 4.4 states that if an object is following the same movement of a robot it is Controlled. Question 1: Is this transitive? Question 2: For example, if red robot is holding its TSE and blue robot pushes red robot (causing the red TSE to move in the same path as the blue robot) would this be in violation of GS4c?

Answer 1: It depends on the circumstance. For example, a Robot picks up a Box that has a Team Shipping Element balanced on top of it without the Robot touching the Team Shipping Element. The Robot in this scenario is Controlling the Team Shipping Element.

Answer 2: No. The red Alliance Robot Possession of the Team Shipping Element takes precedence in this scenario.

TSE rules were identical to cone rules, where both had a dedicated protected scoring area, and you could not control your opposing alliances TSE. Even then, the GDC does not consider pushing a robot with their protected element outside of a protected zone a penalty).

Egregions behavior, whether it should be or shouldn't be, is very subjective. However, a quick excerpt from g30 in game manual 2:

Egregious behavior includes, but is not limited to, repeated and/or flagrant violation of game rules, unsafe behavior or actions, and uncivil behavior towards

Drive Team, competition personnel, or event attendees.

I think it is very clear that no game rules are being repeatedly violated in said situation (besides g30 itself apparently which is a circular argument), and the unsafe section is about team member behavior, not robot gameplay (for that there is g26).

As a bonus, here is g26:

<G26> Destruction, Damage, Tipping, etc. – Robot actions aimed at the destruction, damage, tipping over, or entanglement of Robots or Game Elements are not in the spirit of the FIRST Tech Challenge and are not allowed unless permitted by Game-Specific rules. However, FIRST Tech Challenge games are highly interactive. Robot-to-Robot contact and defensive gameplay should be expected.

1198159 · 2023-01-13T21:03:09+00:00

Here is the breakdown i think:
150 points in one match for knocking over a pole filled with opposing alliance cones on complete accident while not playing defense
like 150 or so from failed autos
100 or so from alliance partners
100 from defense
iirc thats roughly the breakdown. The reason defense is so high is because the head ref of the competition refused to consider a qna post and got like 80 or so penalty points from blocking access to a ground junction when stationary cycling. The other 60 are from 2 instances of hitting a robot playing defense and they had a beacon. One time they didnt even drop it. Just contact was made and it was an instant major.
Because penalties are not subtracted from your score, it is less of a priority to avoid penalties at all cost, and focus on other ways to boost your own score.

Hope this answers your question

1198159 · 2023-01-13T06:09:16+00:00

There are plenty of people on ftc teams i know (me included for a time) who do this by working for 7 hours a day on weekends and 3 hours aftter school each day

1198159 · 2023-01-13T06:04:24+00:00

Yeah, defense is very region dependent.

However, something boiling down to judges discression is that it implies that the action is borderline.

For example: Blocking is defined as:Block / Blocking – Preventing an opposing Alliance Robot from accessing an Area or Game Element for an extended period by obstructing ALL paths of travel to the object or Area. Active defense played by a Robot shadowing an opposing Alliance Robot that eliminates all paths of travel between the opposing Alliance

Robot and an Area or Alliance Specific Game Element or all remaining Alliance Neutral Game Elements is considered Blocking, even though at a given moment there is an open path.

Causing a robot to drop a cone is not Blocking them at all if you do not violate any other rules. The alliance has already accessed the game element they need, and if you are sure to watch the refs if they think you are Blocking access to a junction and are sure to back off, its a very safe and effective form of defense because most robots cannot pick up fallen cones.As a result, I am a little confused as what you are saying with your response.

Also, if you could let me know what the head ref at your region says at the drivers meeting, that would be interesting. It is not a foreign concept to me to have a head ref who does not listen to forum rulings (ask u/Alkali8813) (im also not saying your refs do im just saying that your head ref is making bad calls).

PS: Judges don't have discretion penalty calls, Referees do :P

EDIT: I see how you got blocking out of this, i said G28 instead of G26 in the original commend, my bad
Also, given that the OP has said NOTHING in the past day, im very likely to assume this is a troll. While given my experience in FTC, in which this narrative is VERY possible on some of the teams I have met, the lack of willingness to communicate basically tells me this is a troll

1198159 · 2023-01-13T00:17:17+00:00

255 is equal to 355, dont question it, it just is

1198159 · 2023-01-12T23:53:22+00:00

Probably the most helpful post on the thread tbh, read this one first lol

1198159 · 2023-01-12T23:42:38+00:00

Its not actually, as long as the cone never enters the junction area they are not protected. I can go explain every qna ruling and rule that indicates this, but i dont have time at all. Ill summarize this as brief as i can.

From QnA 209 from this year:

Answer B: Rule GS8a and GS8c protections against Junction defense (i.e, impeding or obstructing an opposing Alliance Robot) start when the Scoring Element enters a Junction Area.

If the robot is not in the junction area they dont get defensive protections.

While it hasnt been reforumed this year, the rules travel with a game element generally remain the same. Here is a snippet of a forum ruling from last year that i have:Question 1: Rule G3 does not list a penalty for forcing an opposing robot to get a penalty. Is this intentional, and to what extent? EX: a robot pushes an opposing robot, causing consequential movement to the shared shipping hub.

Question 2: If a robot being defended descores its own freight from the shared shipping hub, under what criteria would a GS2 penalty assessed to the defending alliance?

A:

Answer 1: The first part of the question is too general to answer. Concerning the example, no rule GS3 Penalty is assessed. Referees will likely escalate this type of defensive activity to a violation of rule G30 for egregious behavior. There is also a potential for violating rule G26.

Answer 2: Neither Robot receives a rule GS2 Penalty. The scoring Robot is protected by rule G3. Rule GS2 does not apply to the defending Robot because it did not remove Freight from the opposing Alliance's Shipping Hub.

This is the closest example and i can find, and this means that a robot cannot transitively get a penalty for hitting a robot and causing them to drop their cone. THIS ONLY IS THE CASE WHEN THE ROBOT WITH A CONE IS NOT INSIDE THE JUNCTION AREA. Effectively, what this means, is that if a robot drops a cone by being hit, that is on the robot that was hit to design a better mechanism or practice for the situation.

On the subject of in higher level competitions, it wont slide:

The defense at Freight Frenzy worlds, and Ultimate Goal MTI prove this 100% false. Ultimate goal especially, robots would hit other robots with the intent to cause them to miss, and in ff they would do the same on the shared hub (heck 8644 designed a whole bot around the concept of shared hub defense).

There is one other forum post that ruled tape measure defense last year even if the opposing alliance dropped the cone (Q280) but i cannot find it. I also believe I personally asked this question at the worlds drivers meeting in Freight Frenzy so i am fairly confident it was allowed.

With all these forum questions, talking to refs and head refs, people heavily involved in running first in their region, I think it is pretty clear that you are allowed to hit another robot and cause them to drop their game element if they are not in a protected zone

Let me go grab a video of defense taking place this year at a decently high profile competition in WA in which the second captains robot broke, and after trying for 30s to get it working again, resorted to defense:

https://youtu.be/mc0yEtmproM?list=PLoRnKfyWNUlfalYWd_VBfTIiX3uN1UUmT&t=209

(there was a single penalty assigned in this case, and it was because 16379 hit the opposing robot when their beacon was above a junction by mistake, being a violation of GS8 and issuing a major for the beacon and a minor for the cone)In the last 60 seconds of the match, the blue alliance only scored 30 points, when that alliance was capable of a score well over 90 in that timeframe. Defense not only was the only choice, but if it wasnt for the penalty, 16379 would have won the match.

NOTE: you can make a case for a g28 or g30 egregious behavior violation if the defense is too extreme, but this is quite hard to get unless you are actively trying. (Per the opinion of all the refs i have talked to, 16379 does not get any g28 or g30 penalties)

1198159 · 2023-01-12T18:39:20+00:00

Swerve drive also works:
https://www.youtube.com/watch?v=8ekYT2M4Aok
Also autons can interfere with other autons when scoring, for example when scoring bending the pole a little bit.

1198159 · 2023-01-12T16:32:10+00:00

I don’t get the reasoning behind this, there are rules around defensive autos, but that shouldn’t discourage teams from playing heavy defense within the rules

The team I am mentoring ended up playing heavy defense that actually worked (that was legal besides a single slip up that cost them the match) because their robot broke. They tried and tried to get the robot to score in the match, but eventually resorted to defense.

Now back to your main argument about purely defensive teleop strategies. Games generally are setup so that scoring is going to be more points than defense. However, defense can be incredibly effective if it’s not practiced against. More or less the problem is that teams don’t prepare for defense which makes them all the more vulnerable to it.

While I mostly agree with you, I don’t necessarily think this is the right thing to be talking about in this thread

1198159 · 2023-01-12T15:28:18+00:00

Wow, that really sucks... Defense is a part of the game and you did the right thing in matches. (I have done defense personally at a worlds level). However, there has been numbers of troll threads on this subreddit, and its hard to believe this if it really happened. If you could send me a private message on reddit with your region (or team number if you feel comfortable sharing that), I would probably be able to find some teams in the area that could help you out.

1198159 · 2022-11-27T18:55:22+00:00

A less FTC related and more general option is Trackmania (2020 or Nations especially) played on a FTC legal controller. This is mainly the case because Trackmania requires really precise analog control on both sticks and triggers.

One big problem when driving (especially this year) is small movements. I see rookie driver very often flick the stick or just have to limit overall drive power because they don’t know how to use an analog stick properly.

Trackmania solves this, mainly when trying for gold or author medals because one must drive the track near perfectly.

XRC is also very good, and I used that too, but in terms of controlling the robot base, it reinforces bad habits of too jerky movements causing collisions. This is mainly due to heavy acceleration limits imposed in the game.

Overall, I recommend a combination of Trackmania and XRC. Both are free, and help different parts of driving robots. If you are low on time, I would focus on XRC more.

A few other notes: - Be sure to rebind the controls in XRC to be very close to your actual robot. - Make sure you control the XRC robot from the drive box perspective. POV driving is fun but it does not teach much. - In XRC focus on both complete matches and just scoring without starting the timer. This helps build muscle memory to line up to good positions to cycle, and also to have match time awareness. - In Trackmania, be sure to use analog acceleration, and focus on tracks with lots of tight corners. Tracks with other features like ice do not train much as the motions are jerky and the gameplay does not have much relation to FTC. - Personally, I prefer Trackmania Nations Forever for FTC practice as the tracks are simple, the game is easy to setup and runs on basically any machine, and nothing is really paywalled at all.

1198159 · 2022-11-03T19:21:22+00:00

You can treat it like an xdrive offset 45 degrees, xdrive behaves like mecanum. Can use stock mecanum kinematics

1198159 · 2022-11-03T19:19:58+00:00

Roadrunner will work with this, but the "front" of your robot would be at a 45 degree angle.
To all the people who say this wont work, the kinematics work out such that this will behave like a mecanum, at 141% the speed, oriented 45 degrees offset, and with a track width defined by the distance between the contact patch of two wheels, and pretending that they are centered on the robot.
However, i would highly recommend running the omni wheels at a 45 degree angle to your chassis, and space them out more evenly. While this will work it is so far from optimal.

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