I haven’t worked with one in a while, but I was thinking about the standard advice on applying rubber bands to a DR4B. I think it’s a little bit off. The whole triangle thing is clever, and I’m not saying to avoid that. I’m saying the targets seem to be incorrect. Why? Maintaining uniform force on …

You are right - most teams are doing the triangle wrongly. This uniform tension rubber band method is a lot more than just spamming a triangle at the sides. If one is to look closely at how those pioneers teams did it, they will notice that the different lengths of the triangle matter. Maybe the …

[image] meng: You are right - most teams are doing the triangle wrongly. This uniform tension rubber band method is a lot more than just spamming a triangle at the sides. If one is to look closely at how those pioneers teams did it, they will notice that the different lengths of the triangle m…

[image] NyQuil: Do you have any specific examples of teams that do this well? I believed that the goal with triangle tension was to create a triangle with similar SA from down to up. +1 I’d like to take a look at these teams for future reference. No way to really easily tell the difference.

I actually disagree with this. A lift requires the most force when accelerating. Since the lift accelerates up when it’s fully down and down when it’s fully up, and since it doesn’t take much force to maintain the current velocity, or position if your velocity is 0, I think you actually want the m…

[image] NyQuil: Do you have any specific examples of teams that do this well? I believed that the goal with triangle tension was to create a triangle with similar SA from down to up. There are actually many teams that did it well. [image] Uniformly Tensioned Rubber Band System An…

[image] Anomaly: I actually disagree with this. A lift requires the most force when accelerating. Since the lift accelerates up when it’s fully down and down when it’s fully up, and since it doesn’t take much force to maintain the current velocity, or position if your velocity is 0, I think yo…

[image] Anomaly: I actually disagree with this. A lift requires the most force when accelerating. You’re not understanding what I’m saying. I’m not saying you should have less force at the bottom than you had. I’m saying you could adjust so that you have the same force near the bottom while …

[image] meng: Think you misunderstood the point. What I am saying is that this uniform tension rubber-band system (UTRS or triangle method to most ppl) is misleading, this is because what we are trying to achieve is not uniform tension (or force), but rather uniform acceleration (as much as pos…

[image] Anomaly: Oof, sorry for being unclear. Let me try to clarify: uniform acceleration isn’t really a realistic goal because the lift accelerates from different points. Uniform acceleration from the bottom will require more rubber band force when the lift is at the bottom, while uniform ac…

[image] Anomaly: Ok I think I did misunderstand what you said, but I think you also misunderstood what I said. :slight_smile: The truth is somewhere in the middle. Actually, I understood you really well. But some of it was that I recognized a physics error you were making and just didn’t ha…

Reconsidering DR4B Rubber Banding

VEX V5 General Discussion Technical Discussion

meng January 2, 2019, 12:20am 6

There are actually many teams that did it well.

this is the original idea.

DR4B Tutorial by 333A