Dr4b or Dr6b

I was thinking of using a double-reverse four bar, but I see a lot of people wanting to use Dr6b. Are there much differences between a double reverse four bar and a double reverse six bar, other than how many bars there are?

I’m sure that DR6B reach higher altitudes. The same concept of a 4 bar vs 6 bar.

A DR6B is pretty good for stacking cones really high, but most likely they can fall over. A DR4B can be used as Yerayrobotics said. I prefer using a RD4B because you can stack at a reasonable height.

Isn’t DR6B going to be insanely heavy? I’ve never actually seen one. How many motors and what ratio?

I believe that Team 202’s ITZ robot is a DR6B.

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@J_L_Picard Not unless you use steel on your robot. I would prefer all aluminum if you want it really light.

@Mudkip still that’s a lot of metal

@J_L_Picard I mean, it’s only really the added weight of the middle vertical bar added, right? The top and bottom cut pieces add up to about the bar you’d have with a 4b. Plus bearings and screws and stuff, but I wouldn’t think it’s heavier than a rd4b to the level not to use it bc of weight

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Disco (2587X) used a DR6B for their skyrise bot.

I don’t see the purpose of using a DR6B. I think it is just extra weight and gives you an unnecessary amount of height. Stacking cones that high will just result in them tipping over.

20 cones is: 19*2.75+7+4.8 = 64", so you’ll need a lift the same height as a skyrise lift.

Why would you need a 20 cone stack?

Sorry, wasn’t thinking. But at most, you’d need a lift that high.

I’m going to go out on a limb and say 80%-20% world champion alliance won’t have any stacks higher than 15

I agree with that. If anyone has their game elements kit, they would know once you get to around 15 the stack leans and wont stay very stable

I was guessing that a team that can do 30 cones by itself in a match would be good for Worlds, assuming they got a partner that can also do at least 30 cones (because 30+30 = 60 per Match = WORLD DOMINATION), so that sounds about right to me.

A 6 bar can fold up into a more compact space(front to back) because the outer portion of the parallelograms are vertically offset upward. It is much more complicated though and likely hard to make the extra components fit into that compact space. The middle bars create additional negative torques that increase the further away they are from the drive source. The DR4B is simple and lighter, but will not fold up as small(front to back)and not reach as high.

I can’t find the post, but someone did tests that showed the stacks just collapse after about 23 cones. So 30 might literally be impossible.

Each alliance has 4 mobile goals though so really each team could just score 15 on each mobile goal (which is still quite alot but not nearly as much as 30).

Actually, Karthik ruled that touching cones already stacked on a mobile goal does not count toward the possession limit, so you could theoretically brace the stack to stop swaying.