[TC11] Technic Contest Battle Bots - Discussion Topic

[dr_spock]

I don't think the specifications should change now that it has been out for almost a month.  But then again...clients changing specifications and requirements after work has started is a fact of life in some industries that I have worked in. 

As per the contest rules:

On 2/20/2017 at 0:18 PM, Jim said:

These rules can be changed whenever we see fit to ensure that people follow the intent of the contest.

 

[Appie]

2 hours ago, aminnich said:

I agree with you that you can make whatever you are building smaller, but in this case, some not have a ton of components for the not to perform like it should. 

You bring up the mini contest, the 200pcs maximum part count with the whole idea behind that contest. With the battle bot contest, the size constraint is just a percaution of "we don't want giant bots that would eat the other ones" which is fair, but I still think 45x45x45 is small. And Jim said the original size limit was 35x35x35

 

And rightfully so, Jim is being very generous. Seriously 45x45 is freakin huge: on most 1:8 scale supercars that's pretty much the entire wheelbase, wheels included. And you get a cube of that space. If you can't make a proof of concept in that size for a Lego robot then I don't know what to tell you...

[aminnich]

it can be done, but if the size constraint is increased, i am sure we will see much better bots.  

[AVCampos]

Remember the constraint is for the robot's initial size: after the round begins, it can "unfold" to whatever desired size. I'm sure that would score serious Cool Points with the judges.

[Jim]

18 minutes ago, AVCampos said:

Remember the constraint is for the robot's initial size: after the round begins, it can "unfold" to whatever desired size. I'm sure that would score serious Cool Points with the judges.

That is definitely a valid point. That's why I have added it to the rules in the first place. Okay, let's make it not anymore difficult, or unfair.....let's keep the size limit as it is.

I'm still thinking of adding a week or two to the deadline, because I have lots of things planned around the deadline. So that would work both ways.

I have addded ONE WEEK to the deadline. Size limit remains 45x45x45.

[aminnich]

Ok so with that being said, I would guess that not many bots are going to be 45L tall.  So we can have our bot fold upward, right? Does the bot need to fold down remotely? or can it enter the "arena" with whatever it is already folded down? 

I hope that makes sense.

[Milan]

7 minutes ago, aminnich said:

So we can have our bot fold upward, right?

On 2/20/2017 at 6:18 PM, Jim said:

When the robot is in battle mode elements can be outside of the bounding box.

You can have folded it in any way you want, forward, backward, sides, up and down.

 

10 minutes ago, aminnich said:

Does the bot need to fold down remotely?

On 2/20/2017 at 6:18 PM, Jim said:

Everything needs to be remotely controlled.

Yes.

[Aventador2004]

5 hours ago, Jim said:

That is definitely a valid point. That's why I have added it to the rules in the first place. Okay, let's make it not anymore difficult, or unfair.....let's keep the size limit as it is.

I'm still thinking of adding a week or two to the deadline, because I have lots of things planned around the deadline. So that would work both ways.

I have addded ONE WEEK to the deadline. Size limit remains 45x45x45.

Is the finish date April 17th now

[Seasider]

Not sure if I'm going to be able to enter this, work is chaos at the moment, I'm trying to apply (after a very long time) for my IMechE Membership and also my weekend toy (MX-5) is sick and needs some TLC!

If I can find the odd hour or 2 here and there I'll try, won't be as left-field as i normally do though !

[PKW]

On 20/2/2017 at 6:18 PM, Jim said:

The maximum size of your robot is 45Lx45Lx45L. This is the size when the robot is in idle/storage mode. When the robot is in battle mode elements can be outside of the bounding box. Mind you that there's a battle going on in the arena, so you cannot attach or detach things manually. Nor can you operate other functions manually. Everything needs to be remotely controlled. It is allowed to shoot rockets and other stuff, as long as the trigger is remotely operated.

 

can i make a bombshell replica? it has modular weapon so  a flywheel, an axe and a horizontal spinning bar, i read in the rules that "things cannot be attached or detached, this refer to battle mode only or also to storage mode? easily removable battery box (and maybe room to swap from lipo to normal BB) is counted as illegal? because lots of real robots has this feature and it really matter to change batteries or charge  them without wasting time for repairs.

(spent time reading again all 8 pages + rules , haven't found anything about that)

 

[Jim]

SImply choose one type of battery box for you final entry. Other than that, you cannot attach or detach things when you are operating the vehicle, so you have to choose one of the attachments for your final entry and video.

[PKW]

2 hours ago, Jim said:

SImply choose one type of battery box for you final entry. Other than that, you cannot attach or detach things when you are operating the vehicle, so you have to choose one of the attachments for your final entry and video.

this means (A) that if i build a modular weapon attachment (as bombshell) i can show building of both weapons on the [TC11] topic but i must show only one on the entry reply, or (B) that i must choose one weapon before starting the [TC11] topic, i'm not talking of operating functions, but weapon that need to be changed in the pit like this

http://robotwars.wikia.com/wiki/File:InterchangeableScoops.jpg 

but mine will be not two parts of a weapon but two different weapons

[Jim]

The contest is not about making multiple attachments. Sure you can make two and ask the members which one is better and use that one. So, the answer would be (A), but I don't encourage people building all kinds of stuff to show off in the discussion topic. 

[agrof]

Just an idea, which popped in my mind in the morning, maybe useful for someone.

Instead of BB boxes, there is a way to build rotating blades weight with Ninjago spinners, which are actually quite heavy for their size.

http://brickset.com/parts/design-92547

Combined with this part:

http://brickset.com/parts/6066952

You can build something like this, multiplied. The two spinners can be attached together by liftarms (LDD allows to place 1x1 beam only), or with Bionicle weapons, which have 2 pin holes connections.

If all the studs of the spinners are connected that way, it will result a very massive unit.

 

Edited March 17, 2017 by agrof

[PKW]

There are more simple way to build more heavier and deadly spinner blades: one is the use of motorcycle tyre as weight, I achieved to directly break lego parts with that, not sure if I will rework that spinner for my entry, still have to choose if build my most powerful flipper arm with out reload or a sliding disk that spin up and then slide again the opponent to maximise the momentum (something like dead  metal saw, but faster)

[allanp]

Weight is only half the equation and you can get enough of it by building very dense and beefy which will also make it strong. Speed is the other half of the equation and massively heavy bar spinners filled with battery boxes spin very slow compared to a lighter but solidly built spinner. Spinning bars and fly wheels will only store the energy given to them by the motors. But if they are too heavy friction and flexing causes energy losses resulting in a very weak spinner that bogs down the spinner motor causing it to draw too much power which may cause other issues. 

[PKW]

17 minutes ago, allanp said:

Weight is only half the equation and you can get enough of it by building very dense and beefy which will also make it strong. Speed is the other half of the equation and massively heavy bar spinners filled with battery boxes spin very slow compared to a lighter but solidly built spinner. Spinning bars and fly wheels will only store the energy given to them by the motors. But if they are too heavy friction and flexing causes energy losses resulting in a very weak spinner that bogs down the spinner motor causing it to draw too much power which may cause other issues. 

Don't forget momentum! Having the rubber part (heavier) of the motorcycle wheels on the largest diamever produce a better flywheel effect than the same mass but distributed in all the wheel area, so more weight on the edge can lead to a lighter disk with same energy (at same speef) and so less power consumed by friction and more speed: everything better!

[allanp]

A motorbike wheel I would say is a bit on the light side for this scale but like you say it is very efficient because of the tire on the outside edge. I would say that makes it an ideal spinner for a smaller scale of robot. 45x45x45 is quite large. You could spin the wheel faster using gearing up but that brings it's own inefficiencies. At the same time I would say big bar spinners with battery boxes are too heavy for Lego motors to be efficient. There is a balance you have to have between the power a lego motor can give to a fly wheel and the fly wheel itself for maximum effect. Another thing to consider is when considering the energy of an impact, not only do you have to consider the energy in the flywheel but also the inertia of the opposing robot. A big heavy slow bar may have a lot of energy but if it's not moving very fast it'll just move the opposing robot out the way without damage, whereas a fast moving spinner (like a motorbike wheel as you say) will impart more of it's energy. Think of a car with a scoop moving 1mph and a bullet moving thousands of feet the second. They both have the same energy but the bullet will cause far more damage. So too heavy is bad, but you do need enough weight to be able to store the energy given to it my a Lego motor and I'm not sure a motorbike wheel is quite heavy enough. But if that's what you want to use aim for at least 4000 rpms on that bad boy!

Having said all that, a flipper is a much greater challenge than a simple spinner. So that I think would be more impressive but really you need the V2 2x11 pneumatics minimum. Even better would be the old single acting long cylinders as they move with far less friction. Those really can flip a heavy opponent (or a car like 8448!) if you have enough of them.

Edited March 17, 2017 by allanp

[AVCampos]

9 minutes ago, allanp said:

Think of a car with a scoop moving 1mph and a bullet moving thousands of feet the second. They both have the same energy but the bullet will cause far more damage.

Actually, the bullet does more damage because it concentrates the same energy (which, according to the formula for kinetic energy, is proportional to the mass times the squared speed) in a smaller area.

If you attach a spike to the battery box, it will be much more damaging to a given area, but the area damaged will be smaller.

[allanp]

8 minutes ago, AVCampos said:

Actually, the bullet does more damage because it concentrates the same energy (which, according to the formula for kinetic energy, is proportional to the mass times the squared speed) in a smaller area.

If you attach a spike to the battery box, it will be much more damaging to a given area, but the area damaged will be smaller.

That is also true and should be considered. Good point  . What I was getting at is that because the opposing robot isn't fixed in place you are having to rely on it's own inertia otherwise it will just be pushed out the way immediately after the initial hit without any damage being caused to it. Take the same analogy of the car and the bullet, car is moving at 1mph but this time there is another bullet glued to the front bumper. So now we have two bullets, one moving bullet speed, the other glued to the front of a car moving 1mph, both having the same total kinetic energy. When colliding with a fixed object the damage will be great in both cases. But when colliding with an easily movable Lego model, the Lego model will just be pushed out the way by the slow moving bullet but will be completely obliterated by the fast moving bullet despite their both having the same amount of total kinetic energy and surface area. 

[PKW]

1 hour ago, allanp said:

1) smaller scale of robot. 45x45x45 is quite large.

2) a motorbike wheel is quite heavy enough. But if that's what you want to use aim for at least 4000 rpms on that bad boy!

3) really you need the V2 2x11 pneumatics minimum. Even better would be the old single acting long cylinders as they move with far less friction. Those really can flip a heavy opponent (or a car like 8448!) if you have enough of them.

1) i scale my robot to fit in a 33x33cm square and use only 1 BB so i think i'll stick on this sizes and limitations due to the fact i think bigger lego bots are just inefficient and often results only an artistic form of a sluggish robot with no fun

2) i have an 80.5g sipping disk at 2030 rpm, it is not that bad, it can easily flip bots up to 600g more or less, break lego parts and dismount lego connection

3) too bad lego pneumatic system it highly inefficient for a flipper unless you are working with 10bar and modified pistons, the defaults settings make lego  pistons too slow and really difficult to store a decent amount of air, my old flipper bot was able to flip 1kg of robot with no problem and even start causing structural damages after 3-4 flips, with unlimited (unless battery discharge) number of flips, if you are curious just visit my brickshelf or my youtube, don't want to reveal everyone the mechanism for free ahahah (in the brickshelf foldere there is a lxf file too)

another option, since pneumatics are so slow they only lift and not flip, linear actuators are just better at this

edit: just to clarify, the bot of mine i was talking about is a vertical spinner, not an horizontal one this and the fact of having two little lifting wedges make te robot able to lift the opponent (3-4cm) and hit it from the bottom/side with a more effective angle

Edited March 17, 2017 by PKW

[aminnich]

Do you guys want me to get my engineering professor in on the discussion?  you guys are really gettin deep into this contest, you only have to build a bot, not do calculation on the angular velocity and acceleration of the spinning object at t=5 secs (only my engineering friends will understand that one ) 

anyway, I have a question about SBricks in general; how many motors can I have on one channel? 

Lets say it's 4, can I have a total of 16 motors per SBrick than? Or would the 4 motors only be for one channel? 

Im debating on getting an SBrick or 2, because I can slowly speed up my motors instead of a sudden ON or OFF 

 

Edited March 17, 2017 by aminnich

[AVCampos]

41 minutes ago, aminnich said:

I have a question about SBricks in general; how many motors can I have on one channel?

I'm not sure, but almost certainly you'll hit the current limit built into the battery box before hitting the one on the SBrick. Having said that, I believe you can run at least 2 XLs on one output.

37 minutes ago, aminnich said:

you only have to build a boy

I don't think the moderators tolerate that kind of discussion here.

[aminnich]

Sorry about that, I was replying on my phone and auto correct always likes to correct me, I did not mean boy, I meant BOT 

[krtwood]

One advantage of a battery box is you can adjust the weight inside of it without changing anything else.  Also the bigger the weapon is the greater the chances of actually hitting something.  While you might mainly be only pushing the other bot away (and your own bot in the opposite direction) you are at least getting in a hit and hopefully keeping them away and not able to get close enough to hit you too.  Plus there is the psychological effect to consider.  A big weapon looks like it's going to do damage and our bots are not actually going to fight each other.  So it's as much a question of how people are going to imagine what the bot can do as what it can actually do.