Sunday, January 21, 2018

Day 15: More CAD

Hook geometry to starting to take shape. We love this video by Adam Heard and 973 for designing pneumatic linkages. 

Drive train is moving along, it now has a belly pan and more holes

Arm pivot is more flushed out, we'll be using a colson dead hub in a way it wasn't designed for but it should serve us well in this new role. 


- Spectrum

“Love life. Engage in it. Give it all you've got. Love it with a passion because life truly does give back, many times over, what you put into it.”  - Maya Angelou

Saturday, January 20, 2018

Day 14

Drive Train

Drive train CAD is starting to progress. We'll get the gearboxes and belly pan on over the weekend, and start working on the mounting points for the A F-frame. 



Intake

The prototype virtual 4 bar intake is progressing, but we still haven't gotten fully functional. Ideally this weekend we have version 2 to the point of collecting cubes. We'll need to make a decisions to continue optimizing this design or change course soon. Luckily the intake doesn't have to slow down progress on the rest of the robot.

Climber

Cable management is going to be a big issue for when we have the tailgate and winch installed in the robot. The rope needs to be able to move and extend with the arm during the match, and then pulley free from the arm to allow the winch to pull directly to the hook. Today we prototyped lexan flaps that are close with Velcro. The rope will ride in these flaps through out the match and then be able to pull open the doors once the winch cable is under tension. As for allowing the cable to extend and retract we are going to prototype a system that uses a coil of pneumatic tubing to spring the rope back when it's not in tension, the pneumatic tubing coil should arrive on Monday.

- Spectrum

“I’ve seen how you can’t learn anything when you’re trying to look like the smartest person in the room.” - Barbara Kingsolver

Friday, January 19, 2018

Day 13: Intake motion and Drive Train Speeds

We did have our first meeting back after the winter storm. Most of the team spent the day at Memorial Hermann Hospital getting a tour of the new "da Vinci Xi® Surgical System." We were able to see real world applications for the technology that we learn in FRC. We should have photos soon.

Intake

We progressed on the virtual four bar intake. This prototype has some issues and we have begun building the 2nd version to fix most of the problems. The gif below show you how the arms actually move. 


Climber

We are also looking into systems for folding out our climber hooks and also keeping our tailgate winch cable organized while it is attached to our extension arm, our current plan is use coiled pneumatic tubing to allow the cable to stretch and retract as needed before pulling it in to tension at the end of the match. 

Drive Train Speeds

This is our current drive train gearbox plan. This may still change but we are looking to be very fast this year. The amount of full field runs may down this year but it is very possible that we will crossing the field width wise regularly from portal to scale.


- Spectrum

"Through my education, I didn't just develop skills, I didn't just develop the ability to learn, but I developed confidence." - Michelle Obama

Thursday, January 18, 2018

Day 12: Second Ice Day

We couldn't meet Tuesday or Wednesday this due to hazardous road conditions and closed highways.

We are too the stage we call Block CAD. None of parts are how they would actually be manufactured but they are more than just two D sketches. If we have prototypes CADed of the systems we can use those as place fillers but a lot of the elements are just simple extrusions based on our previous sketches. This stages helps get robot from just a bunch of collective thoughts to something with a little more detail. You can start seeing in 3D where you care going to have packaging problems and where you need dedicate more thought to your final solutions.

Side view of the robot with the arm in multiple positions. The final intake won't have motors sticking out the top to allow it to flip from side to side. 


Side view of the robot with the tailgate attached and shown in the up and down positions.

Head on view with the arm straight up. Easy to see how a fold out hook will be able to latch on to the square tubing of the rung. 

 Head on view with the intake tilted at the frame perimeter, this is if we are potentially reaching over another robot that is already hanging to grab the rung.

 This position show the length of the robot during it's curled position. The final size will add a few inches for bumpers and any length that we make the hook. 


There are still tons of details to iron out with our systems.

Robozone Podcast

If you're looking for more FRC content check out the Robozone Podcast. Gives a bit of insight into FIRST in Michigan and their 500+ teams but also just general FRC information that is great to know.
The 2nd episode of this season was released yesterday.

https://www.chiefdelphi.com/forums/showthread.php?threadid=161599

You can also subscribe to their RSS feed in slack to get updates that way.
http://feeds.soundcloud.com/users/soundcloud:users:249285108/sounds.rss


- Spectrum


"If you can’t understand it, you can’t change it." -Eric Evans

Wednesday, January 17, 2018

Day 11: Ice day in Houston, this is weird

We actually didn't meet for the first time in recent memory. The roads were iced and we have a deep freeze for over 24 hrs which rarely happens in Houston.

Since we can't work on our prototypes, we wrote out our entire current robot plan also their is some updated CAD of the virtual 4 bar intake at the end.

Robot Plan

Drive train and base

- 28.5" long by 24.5" wide
- 4 wheel drive, 6" omnis
- 2"+ ground clearance, it won't be great over the corner but shouldn't get stuck. Should be fine up the platform.
- Not great up steep ramps but steep ramps are bad anyway. Arm may help us out of weird end game situations, forcing it in to the ground, etc.
- current plan is to go with a sheet metal inverted west coast drive (cantilevered wheels on the inside, like 118 last year) to get us a bigger belly pan. 24" is small, our normal wheel wells wouldn't leave us much room and vertical electronics are annoying.
- small size let's us drive under the scale when needed and through the null territory without getting in the way of a partner scoring on the scale. (Also drive under opponents scale if you want to risk it)
- Small size makes it easier for us to get on to tailgates (lifting platforms)
- omnis makes it real hard for us to tip sideways, arm can right us if we tip forward or backward, hopefully we don't need to do that ever.
- 6 miniCIM drive train
- balls shifters
- 5-7 low, 14-16 high gear, need the high gear for portal cycles.(those aren't set and will probably change as we run the numbers better)
- a frame for the arm also acts as frame members

Arm

- pink style arm
- single big rotation joint (about 28" from the ground)
- single telescoping extension
- all sheet metal, all bearings for extension.
- 3x 775pro on the arm with a disk brake so we aren't stalling the motors much. Gearing allows us to curl for the climb when we aren't lifting a partner.
- 1 or 2 775s on the extension, not climbing with the telescoping stage, just hanging from it (has to be able to hold the wait of the robot but not lift it)

Intake

- able to intake from both sides of the robot when the arm flips over
- still prototyping our final solution but worst case it's some version of a sideswipe intake (1114 2015). We want to get the virtual 4 bar intake(look below for a CAD sketch) working but it's definitely more complicated but it should let us intake 11" cubes easier.
- Every cube in this game matters and time wasted trying to turn cubes is time not spent score. Drivers may be able to just approach cubes from a different angle to avoid the 11" face but probably not everytime.
- intake is 2x 775pros, one for each side so we can spin the wheels at different speeds to help with I taking.
- wheels should be able to launch cubes 2-3' for pushing them up to the scale (arm will rest them on the side of the scale for up tilted scales). May include a pneumatic punch if we need more height/distance.
- intake opens and closes with pneumatics, let's us drop cubes and place them nicely.

Climbing

- hooks hard mounted to the arm extension. One on each side we can grab the square tubing from either attack direction.
- hooks fold out or extend to give us more reach for the bar then we get from the single extension.
- solo climb is a curl. That way we can climb second and as long as we can reach the rung we can curl away from the already hanging robot and both get points.
- dual climb is a forklift tailgate that folds out the front of robot, forks are stored along the a-frame for the arm.
- winch is attached to the tailgate so we can get our winch pull location as close to our partner as possible so our climb doesn't lean as much.
- forks have tread or other traction on them so robots don't slide off
- forks have ramps on the sides of them so teams can drive over them.
- some type of retaining bar goes over the partner so they can't tilt off, this won't need to actually tighten to their robot, just prevent them from tipping up.
-winch cable gets mounted to the same hooks we use for the solo climb, as we winch up the arm is back driven to allow us to get it height.
- winch is 2x 775pros
- tailgate and winch can be detached easily match to match, so we can be lighter when we don't need it.


Strategy

- own our switch and the opponents switch as fast as possible and maintain the lead.
- run cycles from portals to op switch and to the scale.
- climb around partners if needed, lift a partner if that's needed as well
- able to pull from the cube zone without knocking to many cubes out of the zone
-able to quickly grab cubes our opponents knock out of their cube zone.
- have third partner maintain your own switch lead and score at least 3 cubes in the vault.
-scoring on switches under defense will be hard since you have to get your bumpers touching the fence to be able to score (reasonably). Lots of spin moves.
favorite alliance task breakdown right now.
1. Score in op switch and the scale, defend them from scoring in their switch.
2. Score in the Scale and your switch
3. Score in your switch and vault, defend your switch
How much time each of those teams spends on each of their tasks and how efficient they are will decide the game. May need to call audibles and have #1 come back from far side and score your own switch to maintain ownership.

Intake CAD


The red sketches show the belts and shafts that would spin the wheels powered by the VP 180 degree adapter. The orange shafts show the movement of the two arms that will move the wheel plates in and out to compress the cube this is powered by a pneumatic cylinder since we only need about 90 degrees of rotation which is 45mm of belt travel. The green sketched belts are used to keep the wheel plate perpendicular to the motor mounting plate those 4 pulleys are directly mounted to the plates they are near and don't even touch the shafts they are around. Note these belt distances are done in CAD yet, this was just to figure out the stacking of all of the components. Many of the distances will change, for bolts, etc.

This gives a large range of open and close in a very small vertical displacement of the wheels.

Most of these pulleys will be printed, if needed most of these can be made from the hex versions but would required cutting a bearing hole into them.

This will allow us to adjust how far we close and open the claw by allow us to adjust hard stops on the pneumatic cylinder motion (or arm motion). 

- Spectrum

“Friends share all things.” - Pythagoras

Tuesday, January 16, 2018

Day 10: Wooden Chassis

Quick update again today. We are continuing some of the testing and finally deciding on a drive train. We didn't want to rush into our drive train design this year as we knew it could change a lot based on our robot design.

We still have some testing to do to make sure we can make the configuration we want work but we should be able to start getting it fully CADed this week.


 We also mounted the wooden arm on the robot base to make sure we will be stable with such a small wheel base (28.5 x 24.5). We added some weight (sand bag) to the arm as well to see if it looked like it would be unstable when we are holding a cube above our chassis..



The intake prototype is still in the works. Our 3D printer had some issues so it was slow going get all the pulleys we needed printed for the testing.

- Spectrum

“The ultimate measure of a man is not where he stands in moments of comfort and convenience, but where he stands at times of challenge and controversy.” - Martin Luther King Jr.

Monday, January 15, 2018

Day 9: Climber Progress and Intake Prototype CAD

Just a short update of what we are working on. 


Our current plan is to have two seperate climbing methods depending on if we need to lift a partner or if we can climb alone.

With a partner we will use our fork lift and winch to lift both our robots at the point between the bumpers. This will let us reduce the amount of tipping during the lift.

When we climb alone we will use a curl at our arm joint so that we can curl away from any robot that has already climbed or if they have bars mounted to their robots.


Intake Prototype
Our intake prototyping has gotten a bit more complicated to be able to meet all our requirements. It uses a virtual four bar belt and a pneumatic cylinder to move the pivots and compress the cube. It also has multiple co-axial movements.
Should have it built tomorrow if we are able to print all the pulleys we need for it. 

- Spectrum

"You cannot shake hands with a clenched fist." - Indira Gandhi