While the title is pretty self-explanatory, I think it would be nice to spark some active discussion on the topic now that we’ve all got the chance to see how both mechanisms run in competition.
My robot currently runs a claw, but I want to switch to a goliath because I believe it is faster and more efficient. The rest of my team, however, thinks we can do things like driver loads equally fast and efficiently with a claw.
I’d just like to get some other opinions on the matter so that my team can consider every aspect possible (perhaps some that were not thinking of, enter you guys) before we make our final decision.
I’ll start: I think a goliath, if built correctly, is the superior option between the two. Because you can just drop down onto cones and instantly pick them up, it makes driver loads extremely quick, reaching stacks of 10+ as exemplified by teams like 1961X (currently a powerhouse in the competition). While a claw is the simpler of the two and requires less build quality for the same results, its ceiling in efficiency is much lower than that of the goliath simply due to the fact that you have to drive into cones instead of just dropping down on top of them, not to mention the fact that claws often don’t drop the cones perfectly straight, so algorithms like an auto-stack become much harder to control.
It honestly depends on your lift and how your robot works. If your robot’s claw is constantly moving up and down, then the Goliath intake may be better. You will especially see goliath intakes on scissor lifts, due to the nature of them. If you are doing a more common chain bar or external loader, the claw is still the way to go. I do have to agree with you on some level, that goliath intakes are better for driver loads, but unless you have a cycling time of less than 2 seconds, there isn’t really a point. But that’s just an opinion of a satisfied claw user.
Personally, my team is a fan of the claw more. I have seen good roller intakes, but I feel like the claw is more consistent as many teams I see try to line up the roller intake which takes longer than the claw generally. I feel like the claw is superior at stacking cones on the field which in my opinion is more important than driver loads anyways
I would agree that your driver’s ability to line up on cones should be a big factor. Our B team has a great driver and rarely misses with a Goliath intake, however our D team uses a claw so that they can run into a cone and grab rather than free aligning in the air.
We use a Goliath intake and we’ve found that depending on how it’s oriented you can grab cones that are a couple inches to the left and right or front and back of the intake if the outer part of the rollers hits it. We’ve also found that it’s better for dropping a cone straight down, our robot can stack three cones without running the scissor lift and the drop we get with the Goliath intake is more reliable.
Just curious, does your team favor picking up field cones or driver loads during the match? And does the fact that the goliath can’t just drive into the cones like a claw (requires alignment in the air) impact you at all, or do you function just fine through that?
Just put the rubber band rollers sideways. Then, you can drive straight into cones to pick them up. I can’t believe how few people (other than ALBA, in their latest, unreleased bot) haven’t thought of that.
We do okay with aligning, driver loads are a lot easier but getting cones off of the field isn’t that bad. It’s gotten a lot better with practice and I think it’s worth it the more difficult alignment because it gives us the most consistent drop
https://youtu.be/6BW5xK2TS5s This looks like it could work Although it looks like it still has less space to get around the cone than a claw does so it would probably still take more precision than a claw. Personally I think that with good enough practice a Goliath that drops over the cones can be just a quick as a claw.
(I’m not sure what team this is, I couldn’t find a number on the channel)
Claws are not only limited to driving into cones. We use a design that can also passively intake the cones by dropping over the top of them. We used zip ties because they can bend around the cone when dropping over the top but also are strong enough to hold the cone when closing around them.
This year my team has used both the claw and the roller intake. We started with a claw and then moved onto rollers. Why did we change? The claw was not only more difficult to align but also had a good chance of not grasping the cone correctly either leading to a dropped cone or a non-level cone which means you need to be more ginger when scoring. While with the roller intake as long as the cone is inside it you can do whatever you want without dropping it. And I would also say the roller is quicker at grabing off the field than the claw just due to the larger tolerence allowed by the rollers. Plus as previously stated the rollers drop the cone very nearly the same everytime making it ideal for a internal stacker like ours as well as the ease of being able to just go down over the driver loads making our driver load stacking time much quicker.
This is slightly off topic, but is the best technique for rollers to gear them up, then program the motors to run at 15 (so they don’t stall when the cone is in there)? That’s the only way I can think of to keep the come in there consistently without stalling the motor if you hold on to it for too long.
What we have done to solve this is situate the rubber bands on the sprockets so each roller has a concave shape to the rubber bands that holds the cones much better even when no motors are running. If you don’t do this type of roller, yes you most probably will have to have a static when nothing is pressed.
By rotating which sprocket tooth they connect to, when we loop a rubber band on one side, we bring them across an then rotate around five teeth to the right which, when done with them all, creates a concave