An amazing machine you have there under driver control. It looks like it has troubles with autonomous building, however. Why was it having problems? Did you ever get your IME problem figured out?
As for scissor lifts being stable, it seems like the biggest complaint I hear about scissors is that they are hard to keep stable. Your machine, on the other hand, looks very stable and agile at the same time.
Really? I was thinking I’ve seen quite a few scissors that are plenty fast. I’ll definitely take that into consideration though.
Looks like your robot hasn’t changed a whole lot since the last comp we had together either, at least between those two competitions. What’s the max you’ve scored solo in a match with it?
When I say fast, I mean relative to other lifts.
At the last tournament, I got 33 in robot skills and scored 81 with 2131D in the first finals match. But, like I said, I’ve built a new robot since then and 2131D will be better too.
Super cool skyrise manipulator, we are working on a new one, hoping to do 4 hopefully 5 skyrise in auto!
I think our scissor lift is pretty stable and pretty dang fast! Tons of PID loop work and it never leans or tilts. Lol! Scissors rock just have to be willing to tune all the time!
What’s your lift ratio? How many skyrises will you be able to score on?
Thanks, building in autonomous is difficult for us right now because the robot has to strafe to the correct position. If it’s off at all the skyrises miss. Another problem is that the current clamp for the skyrise sections doesn’t hold them as securely as I’d like. I never did completely fix the IME problem, there were more important things to work on. I was able to get it working to track distance on one wheel, but no autocorrecting functions. So, I just built a new robot to fix these problems 
I’ll show some competition videos in January.
Scissor lifts have very little sway front-to-back, while being difficult to manage side-to-side. But with some good programming and braces, this is easily fixed. On the other hand, RD6B’s and RD4B’s have both front-to-back and side-to-side sway. The side-to-side sway can be fixed with programming, braces, and balancing rubberbands, but it is difficult to adjust for front-to-back sway.
11.67:1 can run a 9:1 now that we have a new drive. We can fill on 6 and can place the last cube on 7.
I’m guessing a six motor lift and a needle or claw manipulator for cubes?
Good guess lol
I was right?
Yep, made some great additions in a total overhaul the last few days that make the new version amazing! Shooting for 50’s in both skills!
I would think that the large shaft that you have connecting the large gears in the back would have a tendency to cause a lot of friction and perhaps bind a little as your structure flexes during play. I’m guessing you are using that large shaft to synchronize the two sides of your robot. But is there a way to use sensors, pots or IMEs, to synchronize the two sides instead? Or have you tried that already?
It turns out that that shaft doesn’t really do much. It was a pain to put together and it wasn’t worth it. It has no noticeable effect on the stability of the robot.
I’ve mostly finished the new lift. On this one, I made sure everything lines up everywhere and the two sides of the lift are parallel and set square to the base in every way. Doing this and making sure all the spacing is correct makes the new lift much more stable even though there are less braces. So, build quality is the most important thing in how stable a lift is. Another thing we are doing to remove sway is using new shoulder bolts with longer and larger diameter shoulders. This makes all the joints less sloppy. High Strength axles on everything in the middle “tower” of the lift helps too.
Right now I’m tuning the PID for the lift and working on a program that uses two potentiometers to keep it level. The old program basically just changed power levels based on if a button was pressed or not. I’m liking PID more right now because it holds whatever position you want.
What Vex part is that? I know of only one type of shoulder screw, which I think has been around for a while, the size 8-32, and it’s just a stubby little thing.
http://www.vexrobotics.com/276-1408.html
Many thanks for the info on the large shaft that connects the two sides of your robot together. I have some middle schoolers who’ve been jonesing your gear design on a reverse double 4 bar (to avoid using sensors and writing software, I think) and I warned them I thought that the long shaft technique would create more friction than it’s worth.
The rules don’t prohibit you from buying any shoulder screw of your choosing. When it comes to screws and nuts you can *almost *buy anything you want.
This is true. For a while, I was looking at titanium carbonitride coated bolts, but at $10 a bolt…
OMG! Thank you! I didn’t know that! :eek: I’m flabbergasted.
How can I confirm this? Is there some mention of it in the rules somewhere? I’ve been googling this and I see a lot of reputable forum members singing the praises of shoulder screws, but what can I point to in the rules in case my kids get questioned about this at inspection?
Vex Skyrise Manual Rule R7c.
You can see the rule in the manual here
Excellent! Thank you very much!
Telemascope has the rules there. We got ours from McMaster-Carr. I would recommend using standard Vex shoulder bolts for prototyping and any custom sizes you purchase reserve for a final product. Another thing you can do with larger diameter shoulder bolts is drill out the square holes in Vex metal to make them round and much closer to the diameter of the shoulder bolts.