what kind of claw would be best for a six-bar lift in this competition? we tried everything we could think of, but nothing’s working
don’t build a 6 bar lift, Build a DR4B
Like what @The_Original_Kev said, don’t use a 6 bar, use a dr4B. If for some reason you really want to use a 6 bar, I would recommend a claw with a large margin of error. As for a passive claw, a ziptie design would most likely work best.
(keep in mind I have not tried using a 6 bar this season, so i do not have experience with it, i am just guessing)
Let me explain the problem with 6 bars: they move in an arc, a circular motion. Dr4b’s are nice because the intake end moves up and down in a vertical line, which is how you have to stack cones. For a 6 bar, I would recommend a very large Goliath/roller intake. Do you plan on internally stacking?
I wouldn’t be so quick to shoot down the idea of a 6-bar. Just because they aren’t in the meta right now doesn’t mean they don’t have potential. Using a chainbar and some clever programming, our team made a 4bar-chainbar internal stacker that has done really well at our regional tournaments. I don’t see why a 6-bar couldn’t achieve the same results. Even if a team uses a 6-bar without another mechanism for translation, they can make decent external stackers with some drive practice and programming. Regardless, there is no best claw design but for an external stacker, you can use basically any claw. Our team prefers claws that grab from the side because they are generally lighter than roller intakes, and they can pick cones up off of the field more efficiently than a roller intake.
Without another mechanism for translation, 6 bars are very inefficient. There’s a whole lot more effort the driver has to put forth and attention given to just the lift, whereas chainbars, and dr4b’s, and even adding a translation mechanism gives you a predictability and consistency to the movement of your intake that can easily be designed for and around that I couldn’t achieve with a 6 bar, nor have I seen anyone else achieve it. There’s just a lot of effort you have to put into making a simple 6 bar competitive with the other lifts that we’ve seen that this late into the season, I don’t see the advantage IMO. Just my opinion.
hmmm… I think that if you can build a succesful 6-bar, you should be able to build a dr4b. they’re not much harder, and a lot better.
we are using a 4 bar that is essentially like 4 bars or chain bars on the end of dr4bs right now. It picks up cones, we bring the lift all the way up, and the cone drops right onto the mobile goal. I would think that trying to do this with a six bar would be too inaccurate though because it lifts high enough that the cone won’t drop straight down and will miss the mobile goal.
On our robot in competition, our 4 bar stopped working. the problem was we did not have all of the bolts in the right spot, so it broke when it went up!!!
uh-oh. all of your joints should be in the right spot, or else bad things happen.
Yeah. I figured that out in our first round!!!
Be sure to test things and practice a ton before going to competitions!
Yeah. We didn’t even practice driving! We were not prepared!!!
Should we practice every meeting?
Every meeting that you have a completed robot, yes. Also test out functions with your hands to make sure they run smoothly.
thank you! Ill tell my team!!!
What is your team number?
Sadly, I forgot… I have not had a competition in a while. I have one next week!!!
Here was some pictures of my claw that I used in the past. The foam on the top is used to allow the robot to go down at any speed without the cone from slipping out. This increases your cycle time very well. The second thing is the foam pads on the claw, which allow the cone to have a snug fit and a tighter grip, as well as the zip ties are a secondary cone grabber if the cone doesn’t seem to be grasped correctly. The zip ties also double as a way to prevent the cones from swinging at higher speeds. I ran the claw with a 3-Wire servo, and it worked very reliably and consistently.
Hopefully this helps