I would like to go off of what grammatically_uncorrect posted in another thread. Hanging on the bar gives the respective team additional points based on the height /ball they have. To hang the robot has to be touching its own colored bar and not touching any field tile. Lifting a robot off the ground asks for a large amount of power, this power can be acquired by using a higher torque ratio, but this results in a slower speed affecting overall gameplay. This brings me to my question as to how to efficiently hang on the bar without using massive torque ratios.
I would like to keep this thread open to discuss ways to hang on the 40" bar
Do note that a high torque lift that raises/lowers 14 inches would have enough lift to high hang. Then have a release on a rubber-band powered arm that vertically extends 28". A high torque 14" lift should raise/lower in under 5 seconds; pretty good hanging time, in my opinion.
I think that hanging would be a lot easier if the 12" barrier wasn’t there. (sigh) the people in VEX game design love to make us think…
Every game (except Round Up, I’d argue…) has easy, medium, and hard scoring.
EASY- middle zone
MEDIUM- goal zone
HARD- the goals themselves and… you guessed it… HANGING
Now, hanging would be way easier if you just ignored making a 12" robot. I mean, an 18" robot would have WAY more options for hanging. and a much easier time.
as far as hanging with a 12" robot, I’ve heard some of the locals (my team members mostly) express interest in scissor lifts with a latch on the end. This is because they compress so nicely.
Before I abandoned the idea, I was thinking something along the lines of JoeTPR’s idea. Having a normal lift with an extra extension would require little modification. I didn’t know how it would work, but I was thinking about using double acting pneumatic pistons for power on the second stage, though.
OH, and here’s an interesting lift that compresses nicely as well
I agree that the 12" defiantly creates challenges with hanging. I was planning on using a chain bar because of its high lifting height and its not as heavy as a six bar. However I have learned that the chain might snap as I’m trying to hang. Which is why I need something like JoeTPR’s idea also. However my only problem with a stronger torque ratio is that the arm would be slower for scoring the buckyballs and moving the large balls.
This gave me some ideas for new ways to hang, thanks for the input guys it really helped. Ill post an idea I have once its done.
thank you
If you wanted to hang, i would look into either lock and elastic systems, pneumatics, well placed linear lifts, elastic and winch systems, or projext drives
lock and elastic would probably be a system that has elastic powered stored and released when chosen. the trigger could be from shock or from a reloaded combination of systems
pneumatics is a bit crude, but i think you could brute force your way up there with 2 or 3 pistons. you may need a lock, but not entirely sure
a linear lift needs to be directly above the center of gravity. That way the ramp doesn’t angle back and forth. This would probably have to be your lift system due to the amount of motor power needed. However, maybe it’s possible to do raise at an angle. Technically it’s less force, but friction could grow greatly. Going up angled may be more attractive if you fabricate a linear slide with rollers inside
elastic and winch systems would probably be a system which is powered by elastic to raise, and have a huge torque ratio going down. I tried looking into lifts with a near instant raise and slow decline, but my team was disapproving due to the necessary complexity. the instant release and slow decline would nullify the issue with low speed ratios.
projext drives are a pretty clever way to hang, but they pose a huge engineering difficulty without pneumatics. The ability to “stand” and “crouch” can allow you to hang quickly and effectively, but it forces your robot to be light
You could always go with an eight bar similar to what 254D used in Sack Attack 254D 215 Point Robot Skills - YouTube. JoeG made a tread about an eight bar not too long ago https://vexforum.com/t/linkage-design-with-toss-up-potential/24052/1.
For the torque required to lift I see four main power sources, the three already discussed a high torque ratio, elastic assist, a pneumatic lift, and then two speed transmissions.
There was a thread on lift transmissions started by Cory323z a while ago entitled Lift Transmissions (https://vexforum.com/t/lift-transmission/23760/1&highlight=lift+transmissions) and it gives some good examples of VEX transmissions. and it gives some good examples of VEX transmissions.)
We started a thread on this a while ago and we’re happy the discussion has been revived! There’s a lot of good discussion on the old thread as well as a poll if you want to gauge what other teams are doing. If you missed out on it, the link is below: https://vexforum.com/t/climbing/23646/1&highlight=Toss+Hanging.
- Matt
. JoeG made a tread about an eight bar not too long ago https://vexforum.com/t/linkage-design-with-toss-up-potential/24052/1.
For the torque required to lift I see four main power sources, the three already discussed a high torque ratio, elastic assist, a pneumatic lift, and then two speed transmissions.
There was a thread on lift transmissions started by Cory323z a while ago entitled Lift Transmissions (https://vexforum.com/t/lift-transmission/23760/1&highlight=lift+transmissions) and it gives some good examples of VEX transmissions. and it gives some good examples of VEX transmissions.)
hey thanks! that other thread discussion had a lot of great view points and ideas. I think I’m going with a pneumatic/ elastic bar that deploys and nearly bounces my robot up.
No problem and I’m glad it helped. I look forward to seeing how your pneumatic/elastic bar turns out.