My Bot Idea

VEX Robotics Competition Discussion VRC > In The Zone (17/18)
#1

With so many people discussing their ideas on different aspects of the robot(Drive, Lift, Intake), I thought I would join the conversation and display my ideas as food for thought(or laughingstock). Here goes.

Drive:
I am planning on an H shaped[12.5"x12.5"(25 hole)] drive with 4" Omnis on each corner each driven by a separate motor(HS motors). I would have one 13" chassis rail on each side with the wheels on the outside. Then run two 12.5" C-Channels down the middle at 5" from each end of the rails. Questions?

Lift:
I plan on attaching one 15" small angle piece on the opposite side of the chassis rail as my wheels. Then I will attach another of the same metal piece with standoffs to the other one. Repeat the before on the other side. These will be the towers. Then mount a double reverse four bar onto the top of the pillars. The first section of the DR4B made of 4 bars will be 17.5" C-Channel the second section will be made of 2 17.5" C-Channels. The third section will only be made of two 17.5" C-Channels as there will not be two sides of bars, simply one vertical row of two C-Channels that would look like a “u” or “n” depending on the way they were oriented. The would be powered by four motors on the base tower the ratio will be a 15:1 external and Turbo Internal. DO THE MATH, IT SEEMS CRAZY, BUT IT IS IN BETWEEN A 7:1 TORQUE AND A 7:1 SPEED! Questions?

Mobile Goal Intake:
On the bottom of the second section on the DR4B I will run a C-Channel across and attach some hinges that are a little out from the actual lift metal. I will then put a 7.5" C-Channel out on each side going like an “n” or a “u” they will be spaced to fit under the lip of the mobile base and lift it when the DR4B lifts. Questions?

Cone Intake:
At the top of my DR4B I will run a C-Channel across and mount a solid C-Channel going out while beside it I will have a horizontal linear slide with a C-Channel attached to the moving box. Both C-Channels will have anti-slip mat. Then I could drive up to a cone and move the linear slide C-Channel it to grip the cone. Then simply lift it up. Questions?

#2

I am not sure if I am interpreting the drive section right but you should always have a bar on the outside to support your drive. You should think a bit more into the DR4B and how big you want it to be along with how you are going to power it. A two stage gearing really is never needed unless you are working with a flywheel, you will lose a decent amount of torque by having that ratio.

#3

??? A turbo internal 1:5 wouls be a 2:5… not sure how you think thats faster than 1.4:7 Or a 1:7 its a .4 speed vs a .2 speed and a .14 speed, so its double the speed of a HS 1:7, not judging because thats my ratio, but your math is off

#4

I’m using a DR4B as well, but if the high goals are

I’m actually not using a DR4B, but merely a simple 4B. I know. I’m crazy. but, when you think of how the high scoring zones are only 2ft, and how my gear tower is already 2ft tall, not to mention the 2ft long bars I use, I think a DR4B might be overkill, depending on your tower and lift height.

#5

for my robot, I already have:
a 4 ft high(fully extended) 4B lift and tower,
a 3 wheel drive train. its insane, but it works. I have 2 normal wheels on the outside of a box, and one omni wheel on the inside, allowing controlled turning, and controlled movement.

I’m not sure about intake yet… I was thinking something similar to the 24 hrs video…

#6

It says turbo 1:15

#7

the problem with a simple 4b is that its not 100% vertical lift, it does this while a rd4b stays a constant distance from your cone pile

also, a 1:15 just introduces more friction, why do that when you could have a 1:7 or 1:5 with more flexibility with internals
Drawing (6).png

#8

@9065_parker I can do it with ** SPROCKETS! ** Ba dum Ch
I like the sprockets better since they cannot slip or grind like gears. Their max 1 stage ratio is 1:5.

For Reference:
1:7 Speed =about 23 RPM
1:7 Torque =about 14 RPM
1:15 Turbo =about 17 RPM
I have seen videos of each speed and want something in the middle.

#9

How do you end up at 2’ towers when the starting height limit is 18"?
Can you somehow extend them after match start?

#10

@Robot Guy yeah, but with the playing objects being so light, you dont need that high of a ratio, i’m going 1:5 turbos with 2 motor RD4B, and it works fine with the objects.

edit: maybe he’s in vexU? you’d get 24 that way

#11

But I am planning on also using this lift for the Mobile Goals. For more info see original post under “Mobile Goal Intake”

#12

How will you even be able to control that XDDDDD
That’s insanely fast. I think a torque 1:7 is about the perfect speed…

#13

Same though!

#14

pid and presets :slight_smile: besides faster is always better, and its still not as aggressive as i was originally planning

#15

Yea because instead of that horrible grinding of the gears or slipping, snapping chain is better… (sarcasm)

#16

used chain all of this year with a two stage gear ratio never broke in competition

#17

i did at the beginning of the year, snapped like crazy, never using it in a high torque application again.

#18

was it high strength chain(I assume it was)

#19

During worlds, the opposing alliances were very lucky and a chain on our claw broke twice during the match. Since we were reliable, though, our robot was still able to dump 1 cube + 2 stars easy with a claw broken.
EDIT//: But yet again, I highly advise not using chain for your lift, because a stripped lift gear in certain areas can still keep you working, as a broken chain practically disables you. Another thing, the time our claw broke the first time was during the practice match, and the second time was a qualification match when we were with a pushbot.

#20

Boy, everyone but me seems to have had problems with it