Meeting 1/12

[Sunny]

With the shooting mechanisms, possessing the ball mechanisms, and drive train set to go through the prototyping/testing phases, I think the only part of the robot that still has some fuzziness is the hanging portion of the bot.

From what I heard in the meeting, I think the grappling hook idea was really good, but of course we can't shoot it accurately/legally, so I think that idea is kinda not gonna fly. hahaha, fly..oh..jokes.

Towards the end of the meeting, Logan and I were talking about possibly doing a scissor lift.
Pros:
- Scissor lifts are compact, and we can achieve an extremely low center of gravity.
- Scissor lifts are pretty fast. Both in pulling and taking down.
- If the scissor lift, can't hold while the power is off, I can at least think of one way to manually lock the scissor lift in place.
- We can use BOTH pneumatics and a CIM to power the scissor lift & the strength we get by using both will be pretty amazing.
- We can mound the scissor lift in the center of the chassis and angle it to shoot out forward.
- Once the robot gets up, we can even create a latch that latches onto the bar, and thus relieves the scissor lift. (Carabiners)

Cons:
- Scissor lifts are a tricky mechanism. If they're built wrong, they can be horrible and clanky.
- When scissor lifts get too high, they can be shaky, and in the really unstable, but that all depends on how it's built.
- An arm can sit rather high and with the arm there, it would definitely raise our center of gravity.

IMO - I love scissor lifts and what they can do for us. I just feel that if we can built a structurally sound one, then we can create a good lift, but ONLY if it is extremely stable.


The second idea that got thrown around was a simple arm.
Pros -
- Simplicity. There's nothing too complicated about a arm with a couple of hooks
- We can use a worm gear to torque up the arm. Ultimately I believe that a worm gear is the only thing with enough torque to stay put after the power is turned off.
- We can create a system on the chassis so that when the chassis reaches up to the bar, the chassis can latch onto the bar.

Cons:
- An arm will most likely have to be put up on end of the chassis. That means that the arm will face significant torque when going up.
- The chain in the arm might not be able to hold the amount of the weight it most likely will hold.
- An arm can sit rather high and with the arm there, it would definitely raise our center of gravity.


Clarifications
1. When thinking of lifting/staying in place designs, I believe that it will be a good idea to create designs that can raise 120 pounds and support 360 pounds. Granted that 20 seconds is not a long time, and that the chances that 2 other robots can climb on top of us are low, but I think that the top tier robots will be able to do that.

2. When I was trying to figure out the distance between the rollers, I realized that there was discrepancy on the actual radius. A size 5 ball is said to have a circumference between 27-28 inches. Which translates into a radius between 4.29718346 and 4.45633841. I am going to assume a middle value and say the radius 4.375"

[Tanner]

A scissor lift sounds like a neat idea, though the hard part that I find would be getting the system to endure ~360 pounds of stress at maximum. With pneumatics, you've got lots of pressure on the piping/cylinder or with CIMs you've got a lot of stress on whatever you decide to use to power the lift. Either way you'd need to relieve stress off the system. There's like a one way gear which we could use to prevent the lift from collapsing, but that depends what we use to lift it up in the first place.

Only problem I see with anything for grabbing onto the bar is making sure the device stays attached to the robot under all that stress.

Bit confused on the arm idea, but I guess we can discuss that tomorrow at Lunch/Physics.

About your soccer ball wheels of science (sorry - had to), what if we use some sort of rubber band system to make sure the ball is snug, but have one of the wheels attached to a motor so it can swing out of the way to accept a new ball or get rid of one.

And to add to the oddities of the soccer ball sizes, there's talk on CD about every brand of ball being "different" though I kinda doubt that it will affect robots too much.

-Tanner

[Sunny]

A scissor lift sounds like a neat idea, though the hard part that I find would be getting the system to endure ~360 pounds of stress at maximum. With pneumatics, you've got lots of pressure on the piping/cylinder or with CIMs you've got a lot of stress on whatever you decide to use to power the lift. Either way you'd need to relieve stress off the system. There's like a one way gear which we could use to prevent the lift from collapsing, but that depends what we use to lift it up in the first place.

Talking on forums is not the same as talking in person. I'll try to explain tomorrow during lunch.

And like I said, it'll depend on how well built the scissor lift is as to whether or not it can lift 120 pounds.

Only problem I see with anything for grabbing onto the bar is making sure the device stays attached to the robot under all that stress.

As for staying attached...that's the hardest part...I know that the carabiners themselves are designed to handle lots of weight, but I think the actually attachment to the chassis might not stand. We might have to do a combination of glue, weld, and screws.

Bit confused on the arm idea, but I guess we can discuss that tomorrow at Lunch/Physics.

It's just like the arm in '07 but powered by a motor...

About your soccer ball wheels of science (sorry - had to), what if we use some sort of rubber band system to make sure the ball is snug, but have one of the wheels attached to a motor so it can swing out of the way to accept a new ball or get rid of one.

I think you mean the rollers? I'm not exactly sure what you mean, but I'm working out the dimensions of the system right now. I think if you're worried about the rollers sticking to the ball, I believe that the linear speed of the rollers will be faster than the ball ever will be. So once we "kick" we can have the roller start rolling outwards or whatnot.

[Tanner]

Yeah, we can talk tomorrow.

I think you mean the rollers? I'm not exactly sure what you mean, but I'm working out the dimensions of the system right now. I think if you're worried about the rollers sticking to the ball, I believe that the linear speed of the rollers will be faster than the ball ever will be. So once we "kick" we can have the roller start rolling outwards or whatnot.

Well, if we're worried about the variances in ball diameter, we can just have a simple system to adjust the rollers as so that it can take in a smaller/bigger ball while still being able to contain it.

-Tanner

[Sunny]

Well, if we're worried about the variances in ball diameter, we can just have a simple system to adjust the rollers as so that it can take in a smaller/bigger ball while still being able to contain it.

-Tanner

I think that we can allow a .075" room for error in ball radius. .