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-   -   pic: 6-sided tank drive (http://www.chiefdelphi.com/forums/showthread.php?t=130318)

AdamHeard 19-08-2014 13:18

Re: pic: 6-sided tank drive
 
Quote:

Originally Posted by GrifBot (Post 1396939)
Fair enough. It is true that they happened this season a lot, but this was due to the lack of mobility some robots had as they waited for the ball from the human player. On a good driver, t-bones tend not to be effective as a good driver will stay in motion as much as possible.

There must have been some AWFUL drivers on Einstein this year.... and 2011... They were getting T-boned all the time! ;)

Someone get these teams some better drivers :confused:

g_sawchuk 19-08-2014 13:24

Re: pic: 6-sided tank drive
 
Quote:

Originally Posted by AdamHeard (Post 1396942)
There must have been some AWFUL drivers on Einstein this year.... and 2011... They were getting T-boned all the time! ;)

Someone get these teams some better drivers :confused:

It really depends on the game. It's true, this year was difficult to avoid being T-boned as most robots were incapable of driving right by the human player station without stopping and successfully getting the ball. Mixed with that and the fact that it's hard to move and pass the ball, it was one of the better years for t-boning, but still, t-boning is not what I would consider a very effective defensive strategy most years.

Andrew Lawrence 19-08-2014 13:32

Re: pic: 6-sided tank drive
 
Quote:

Originally Posted by GrifBot (Post 1396943)
It really depends on the game. It's true, this year was difficult to avoid being T-boned as most robots were incapable of driving right by the human player station without stopping and successfully getting the ball.



Quote:

Mixed with that and the fact that it's hard to move and pass the ball, it was one of the better years for t-boning, but still, t-boning is not what I would consider a very effective defensive strategy most years.
Since Adam is too modest to boast about his team ( ;) ), I'll be the one to inform you that that is a very dangerous and mostly incorrect statement to make.

evanperryg 19-08-2014 16:08

Re: pic: 6-sided tank drive
 
Quote:

Originally Posted by AdamHeard (Post 1396933)
You can more efficiently optimize the use of the perimeter sizing by moving the front/rear wheels to inside the frame, and making the center wheel wider.

That's how I had it laid out originally. Thankfully, I kept the other design around :D

Quote:

Originally Posted by GrifBot (Post 1396939)
On a good driver, t-bones tend not to be effective as a good driver will stay in motion as much as possible.

A good driver should be able to avoid defense, yes, but a good defensive driver should be able to get a t-bone or two.

tickspe15 20-08-2014 03:18

Re: pic: 6-sided tank drive
 
If tbones were rare and could be easily avoided by good drivers you would not see teams like 254,971,973,148,1114,118,1730,33 and countless other elite teams dedicating engineering hours, money and weight to mechanical aids to get out of pins.

This year we were caught in pins constantly and it slowed us down significantly while simultaneously wearing down our wheels. Often less high scoring teams don't face the same level of defense as their higher scoring counterparts so their robots weaknesses are never exposed.

Abhishek R 20-08-2014 10:42

Re: pic: 6-sided tank drive
 
Wouldn't a hexagonal shape limit how close you can get to the outside walls of the field? I'd imagine if you skim the wall, you would end up being spun in some direction.

evanperryg 21-08-2014 07:08

Re: pic: 6-sided tank drive
 
Quote:

Originally Posted by Abhishek R (Post 1397108)
Wouldn't a hexagonal shape limit how close you can get to the outside walls of the field? I'd imagine if you skim the wall, you would end up being spun in some direction.

In some cases, this is good. Some bumper materials have a lot of friction, so if you get caught up on the wall, it can be a pain to get away.

Quote:

Originally Posted by tickspe15 (Post 1397084)
If tbones were rare and could be easily avoided by good drivers you would not see teams like 254,971,973,148,1114,118,1730,33 and countless other elite teams dedicating engineering hours, money and weight to mechanical aids to get out of pins.

I agree that tbones are very common and drivers should be prepared for them, but I don't think I've ever seen a team make a mechanism specifically to break pins.

Arpan 21-08-2014 12:18

Re: pic: 6-sided tank drive
 
Quote:

Originally Posted by evanperryg (Post 1397339)
In some cases, this is good. Some bumper materials have a lot of friction, so if you get caught up on the wall, it can be a pain to get away.



I agree that tbones are very common and drivers should be prepared for them, but I don't think I've ever seen a team make a mechanism specifically to break pins.

FRC 1114- drop down omni wheels

FRC 118- Drop down omni wheels

FRC 971 - Unique chassis shape

just 3 off the top of my head

Zaque 21-08-2014 12:58

Re: pic: 6-sided tank drive
 
Quote:

Originally Posted by Arpan (Post 1397385)
FRC 1114- drop down omni wheels

FRC 118- Drop down omni wheels

FRC 971 - Unique chassis shape

just 3 off the top of my head

I believe 1986 had a drop down omni wheel up front also.

Boe 21-08-2014 13:04

Re: pic: 6-sided tank drive
 
Quote:

Originally Posted by Arpan (Post 1397385)
FRC 1114- drop down omni wheels

FRC 118- Drop down omni wheels

FRC 971 - Unique chassis shape

just 3 off the top of my head

As well as a large number of teams using lower friction bumper materials, off the top of my head I can think of 971, 67, 1678, 1717, 254, 148, 1114, and 2056.

Andrew Schreiber 21-08-2014 13:30

Re: pic: 6-sided tank drive
 
Quote:

Originally Posted by Boe (Post 1397394)
As well as a large number of teams using lower friction bumper materials, off the top of my head I can think of 971, 67, 1678, 1717, 254, 148, 1114, and 2056.

In the 67 case I recall it was at least partially for their intake based on what my brother said.

mrnoble 22-08-2014 23:01

Re: pic: 6-sided tank drive
 
My students have spent a chunk of their summer designing a hex chassis 8WD because of this very problem; we saw lots of t-bones, and we contributed to a fair number of them. ;) We finished 3D printing the narrow/wide wheels this evening. I've been researching new bumper materials, and the mixing of materials for maximum benefit whether defending or trying to avoid pins. Great stuff!

evanperryg 23-08-2014 15:13

Re: pic: 6-sided tank drive
 
Quote:

Originally Posted by Andrew Schreiber (Post 1397397)
In the 67 case I recall it was at least partially for their intake based on what my brother said.

If that's true, then 67 is the only example of a separate mechanism being used to break defense. The drop down omnis/chassis shape are drivetrain-related mechanisms.

Aren Siekmeier 24-08-2014 19:38

Re: pic: 6-sided tank drive
 
Quote:

Originally Posted by evanperryg (Post 1397744)
If that's true, then 67 is the only example of a separate mechanism being used to break defense. The drop down omnis/chassis shape are drivetrain-related mechanisms.

What? 67's choice of bumper material may have been unrelated to the drivetrain and pinning, and driven rather by the intake, is what Andrew is trying to say. And drop-down omnis are definitely a separate mechanism.

Andrew Schreiber 24-08-2014 20:00

Re: pic: 6-sided tank drive
 
Quote:

Originally Posted by evanperryg (Post 1397744)
If that's true, then 67 is the only example of a separate mechanism being used to break defense. The drop down omnis/chassis shape are drivetrain-related mechanisms.

The bumper material was primarily a function of their intake mechanism.


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