2 or 4 motor DR4B

So I have asked before about whether or not a 2 motor lift was a good idea for this game and, from what I could tell, I deemed the results underwhelming. I believe this was mostly due to my phrasing and/or my poor ability to present details in text form. So, all this aside, here is my new, rephrased and redone, question to ask you forum peeps.

So, from what I have seen, all the stacking robots so far have been able to make it with 2 motor DR4B lifts as opposed to a 4 motor DR4B. I was amazed to see that the DELTA robot makes it by with only 2 motors and still maintains good lift speed with full c-channels and a “not-quite-so-small”, very effective, intake. I have set my standard for cap bots with this awe-inspiring DELTA bot, but I am not quite so sure how anyone could go through with only a 2 motor DR4B this year with the heavier game objects, heavier intakes, and still maintain their lifting speed. What am I missing that allows other teams to do so well with 2 motor DR4Bs that our team wasn’t even able to do last year with lighter game objects and such? (of course we were a first year team, but the only thing I see to help a possible lift is making it all-aluminum, as opposed to us having only 2 steel channels and everything else aluminum)

Is there something I am missing? (better rubber banding, better lift planning, anything that could possibly allow us to make it by with a 2 motor lift this year)

Uh, this year’s objects are significantly lighter than ITZ’s comparable mobile goals. I don’t quite remember, but I don’t think caps are very different from cones. They may even be lighter. I just forget and don’t want to look it up.

Yes, your lift should be allumin. I’ve built lofts where the heaviest thing was the gears. Additionally, your intake doesn’t have to be too elaborate. Unless you’re feeling adventurous, start Simple and work your way up.

2 motor lifts are definitely doable this year. Rubber bands are certainly helpful, and there are threads detailing how to use them. It’s all about using a light gearbox with the minimum torque, resulting in maximum speed.

Another mistake I made my rookie year was to put my lift motors on the base tower, rather than in the middle section. I had to transfer energy such a longer way than I had to.

Another thing to watch out for is where you place your linkages. Putting them closer together allows for more reach, but it takes more torque to move it. It depends on how much space you have.

If you have V5, a One motor lift is probably pretty doable.

Pictures will help. The community tends to be more helpful with very specific problems, rather than a “Help, I need ideas” type post.

This thread is simply trying to either start a discussion between doing either 2 motor or 4 motor DR4B, trying to find the pros and/or cons of each, or the see if there is a clear winner. From my view, seeing what happened last year with our DR4B [rubber-banded (the effectiveness of which is still up to discussion), all aluminum (except for where limited parts restricted our use of aluminum, which was only on two bars) , and with mid-section mounted motors as opposed to tower mounted motors] The only videos or images I have was our “joke” reveal from last year showing our lift’s incapabilities (which were dealt with, but were exaggerated by the joke reveal). I simply put this conversation out here as a catalyst for a started a discussion for either side, with the end goal being, our team able to make up our mind about what to do about it.

If you would like to see our last year robot “reveal” I would be happy to oblige, but I do not think there is much to gain from seeing it.

While I don’t have much to add. I would firstly recommend that if you are using 2 393 motors to power from supporting towers so the motors wont have to lift their own weight. Also I dont see a reason not to use aluminum everywhere.

If you are using V5 you can do a one motor dr4b, if you are using 393 you can also do a one motor dr4b it just has to be really carefully build and rubberbanded. Also your cap intake has to be pretty light, and it has to be a compact dr4b.

Keep in mind with a dr4b you can not lift it outside of the expansion at all. With a 4 bar you can lift it a little. This should not matter if you use an active flipper.

So this is supposed to be with 393s, I guess I failed my goal of getting a better detailed explanation, but anyways…

And, just to be clear, im not saying there is a good reason not to use aluminum on a lift. I was simply saying that a limitation on parts prevented us from using aluminum for every single bar, in addition to the envy of other teams in our program, but we managed to get away with all aluminum except for just two bars.

Keep in mind this is not so much about our team specifically, just mainly talking about what you need to do to achieve a two motor DR4B or if a 4 motor DR4B would we better. Really we are just trying to provoke general conversation here, not just a “oh hey do the thinking for us” type thing, and we hope that other teams, not just our own, and the teams that participate in the conversation will be able to learn something from this.

You are free to bring up anything you deem necessary or specifically important to the conversation, it is meant to be fairly open-ended.

Hot dogs are sandwiches.

But really though, a four motor would be inevitably faster, at the expense of using more power and two more motors that could’ve been used elsewhere. A two motor is totally viable, though not the best choice if you have the extra motors to spare.

Personally, I would only use 2 motors on a dr4b for this game. I fell like 4 is a little unnecessary for the minimal amount of weight that needs to be lifted and the amount of times you actually need to lift up and down. Plus, if you wanted to do both, lift caps and shoot flags, you have a lot less flexibility if you’re investing 4 motors into a lifting mechanism. Nevertheless, a 2 motor dr4b will likely stall if you have friction, slop and lots of weight in your lift. More motors will never fix the problem of poor build quality. Use proper bracing, tune your rubber banding, use grease or lube, make sure there is no slippage, use screws as joints, etc… Good build quality Is the key to any fast, efficient lift. 202z, 929u and 5225a are all great examples of effective, fast, 2 motor dr4b’s if you want some inspiration.
Although I have to note, flywheel gang all the way!

i don’t think that reverse double four bar is even necessary this year, you could probably reach with a chain bar or four-bar, or maybe even a six-bar, but not a double reverse four-bar

I did a 2 torque 393 motor 1:7 rd4b lift and it worked just fine it also was able to carry a weighted flipper at the front. It wasn’t fast but not like it needed to be. I used rubber bands to assist it as well.

what is it with people overbuilding lifts this year?

DR4Bs are linear, so they outweigh 6 bars for me. Also, they take up less space on the robot.

The thread is called “2 or 4 motor DR4B.” Not “Should I build an rd4b?” or something similar. Please stay on topic instead of de-railing a thread for no reason.

As for the original question, definitely make all your lift aluminum; it helps immensely with weight. Past that it’s simply important to get rid of as much friction as possible and make sure the lift is braced well. If it leans a lot then it’ll be hard to get anywhere with it. Once you got that down you need to spend some time tuning your rubber bands. The lift should be able to be pushed almost anywhere within its range of motion and stay there from the rubber bands. Hope this helps!

I think however the 1010x rd4b design for turning point was pretty efficient. They were able to quickly score caps on both pole heights and still able to be fast and do balls. They did however use V5 but if someone were able to replicate it in V4 with a one motor lift and one motor flipper…that would be pretty cool

@dsibal 1010x? Mind linking a video? I don’t think I’ve seen their reveal. (Unless it doesn’t exist…)

link text
You will find them in the finals.

It really depends what your motor distribution is. if you can get by with a 2 motor dr4b, that’s great, but if you have 2 extra motors, I suggest putting them onto the dr4b as opposed to on the drive. I just don’t see dedicating 4 motors to lifting a cap really all that great.

Agreed. Motor distribution is important and ties directly to the objective of your bot. If you want to build a flywheel/2 ball catapult in addition to a dr4b because you want to be able to hit falgs as well as score caps, 2 motors is almost necessary. If your focus is purely caps, it depends on how strong you want/need your drive train to be and how experienced you feel in making dr4b’s. Making a 1:5 HS dr4b and making it well is difficult and not a good starting experience into the world of dr4b’s. I personally, if I was doing just caps, (but i’m not because flywheel op) I would use a 2 motor dr4b and have a really strong drivetrain, but thats my personal preference and that stems from making 5 dr4b’s and a love of 62A’s worlds bot.

What about a 1:7 One motor lift? I feel pretty good with DR4Bs, but maybe not the world authority on them. Definitely in my organization/school, though.

If you have a 1 motor dr4b, and a one motor cap flipper, making sure it super light yet sturdy, and plan to only be a cap bot, you could have a 10 motor drive train… I like the way you think!