Virus Robotics scissor liftt improvment suggestions

Hi all,
We are team 4915 a UK based team. For this Skyrise season for the first time we have attempted a scissor lift system. Before building we trawled pretty much every scissor lift related post on the forum and we have attempted to implement as many of the things we read as possible. Overall we have been fairly happy with the end result. However, despite spending a long time tinkering it we are still encountering a few problems with our lift system (occasionally it wobbles or becomes lop sided and it is generally very slow.) With UK nationals coming up in a few weeks we want to attempt to make our lift as effective and fast as possible. we thought we would throw it open to the many experts on the vex forum to ask for suggestions or tips on how to improve our lift and/or what we should consider should we decide to rebuild our lift for nationals. Any suggestions would be much appreciated

Thanks in advance


Robot specs:
4 motor 1:1 drive
4 motor 1:21 lift
2 motor 1:1 intake

Videos of robot:


4 motors at 21:1?!

I would definitely make those speed motors if not speed motors on a 15:1 reduction. With strong elastics (you might want to add some more from what I can tell in the pictures) it should lift easily and be much faster at either of those ratios. Rubber bands are your best friend.

I can’t tell as much about the supports between your scissors from the photos, but if you’re having swaying issues, maybe make them a 1x5x1 c channel support instead.

Other than that, it looks really good. Best of luck!

We were running four motors on a 1:15 but we found that it resulted in our robot being unable to lift 3 cubes pretty much at all so we switched to a 1:21. Even now it seemse to struggle to lift three at times? Maybe more elastics is the key

Hmmm. I would definitely add some more elastics, but a ratio change right before nationals might be risky if it didn’t work for you before.
Maybe you should just focus on driving practice and programming? A strong robot with great drivers can be better than a stronger robot with inexperienced drivers.

Weight is the key here I think. Rubber bands will assist int he lift but can get rather springy with undesirable effects too.

You have aluminum but the conveyors tend to be much heavier than you think.

Any way to have a single conveyor in the center assisted by two chains where you currently have the conveyors? Those plastic tank tread elements weigh more than you think. The platform for the mechanism looks to have a lot of metal too that needs lifting that a cube might replace that weight. You’re looking for under 1.5 pounds difference in weight which may not be that much.

Your video has you grabbing three at one point. Does it not always work?

What we did to help ours was have three bars on each side, so we had one c-channel in the middle of the arm and two more on the outside to help with the stability. When we only had two bars on each side, we had a lot of problems with gears bending, diminishing the efficiency. I’m not the builder for our team, but this is what they did and it has been working for us.

Btw, we are 21:1, which works for us. 15:1 is possible, but you need to have a refined and very squared off lift.

and the most important things are elastics; they’re pretty much free motors :slight_smile:

It always picks up three but it ses that one side often lifts faster than the other when lifting three cubes, this results in the lift sometimes being unstable. The suggestions about reducing weight are good ones and something we will look into. The lift works fine but it never seems to be quite as smooth as we’d like it/have seen other teams have it.

Thanks for all the suggestions thus far, lots of good ideas- we aim to reduce the lift to 1:15 for nationals (three weeks time.)

Hi Virus, does the skyrise intake work alright? I know you are mainly a cube robot but whenever I saw you near the skyrise I didn’t really see it work all the time.

Also, can u run the intake of 1 motor and gear it somehow or does it need to be two?

See ya at nationals!