Legged Robots

[davidthefat]

Were any legged robots actually been made by a team and competed with? I believe that it is a very good form of robot locomotion. There are 1, 2 , 4, 6 legged robots that I know of, even Leg/Wheel Hybrids like the RoboTrac. How come they were never really attempted by any teams? I completely understand the cost of the robots, but 1 competition is like 6k, I can make a decent sized 6 legged robot with that budget, just by not going to 1 regional.

RoboTrac:


The Epicest 4 legged robot in the world:
http://www.youtube.com/watch?v=cHJJQ0zNNOM

People can say that it is unstable... But you only need 3 points of contact to the ground minimum to be stable, the Hexaped robots are highly stable.
http://www.youtube.com/watch?v=-Soq9qpK5Ac

[Vikesrock]

Maybe I'm missing something. Can you list some advantages you see to a legged robot over a robot with wheels for FIRST applications?

I'm not even going to get into the disadvantages I see until I figure out what the benefits are.

[davidthefat]

Originally Posted by Vikesrock

Maybe I'm missing something. Can you list some advantages you see to a legged robot over a robot with wheels for FIRST applications?

I'm not even going to get into the disadvantages I see until I figure out what the benefits are.

Stability (6 Legged Robots)
Adaptability
Maneuverability
Innovation

[spacewolfx]

Originally Posted by davidthefat

Stability (6 Legged Robots)
Adaptability
Maneuverability
Innovation

how does it be more maneuverable than a regular wheeled robot?

[davidthefat]

Originally Posted by spacewolfx

how does it be more maneuverable than a regular wheeled robot?

You can literally walk over the bump, Not really affected by height change, You can even jump if you get that far, I applaud you. IDK but Dogs can go anywhere, they have 4 legs.

[Vikesrock]

Originally Posted by davidthefat

Stability (6 Legged Robots)

So you are suggesting that a legged robot that has 3 contact points at a given time is more stable than a wheeled robot with 4 or more contact points?

Maneuverability

I have never seen a video of a legged robot I would consider more maneuverable than a drop-center 6 wheel FRC drivetrain, not to mention something like a mecanum or swerve drive.

Adaptability may be debatable, I don't know enough about legged robots to say whether they are more or less adaptable to different terrains (assuming that is what you mean).

Innovation is definitely an advantage of a legged robot. If that is one of the goals of your team that should definitely factor in. Personally I don't value innovation for innovation's sake in this competition for teams I work with. I always work to have us design the best robot to play the game we can, if that means that some parts are tried and true, boring things then so be it; if it means that we need to go somewhere teams haven't gone before than that's fine too.

I definitely understand and respect teams that try each and every year to come up with something completely innovative. I think that's really cool. It's just not for me.

[BHS_STopping]

If we're going to be loose with our definition of "legged," I would consider Beatty's 2002 machine to be a "crawler" of sorts. Check out some of their videos on TBA, it's really an elegant mechanism. However, they weren't champions in 2002 because of the qualities you indicated. In fact, their machine was simply very slow and powerful, but guaranteed a victory if they could snag all 3 goals at the start of a match.

Their mechanism was simply two sets of one-way shoes which slide forward on the carpet. In this sense, the robot could easily be pushed forward, but impossible to stop if you were pushing backward. It would take a minute to get where it needed to go, but the simplicity of the design (469's mechanism reminded me of this this year) was just phenomenal.

[wo-bot 141]

team 71 in 2002 oe 2001 i cant remember. but any ways they would flip down garb the goals and crawl over to the other side of the field. call it the game breaker bot that year if you like. but they used legs to get across if i recall. so legs can be used for power when speed is not needed.

[davidthefat]

Originally Posted by BHS_STopping

If we're going to be loose with our definition of "legged," I would consider Beatty's 2002 machine to be a "crawler" of sorts. Check out some of their videos on TBA, it's really an elegant mechanism. However, they weren't champions in 2002 because of the qualities you indicated. In fact, their machine was simply very slow and powerful, but guaranteed a victory if they could snag all 3 goals at the start of a match.

Its the giant one that has the 2 big arms? Dang, thats pretty epic, but so slow

[Dancin103]

It's a pretty cool concept, legged robots can move pretty quickly. I still think wheels could move faster in the FIRST robotics world because it's a concept that we have developed and been working with for some time now. Just my two cents.

Cass

[Chris27]

Originally Posted by davidthefat

Stability (6 Legged Robots)
Adaptability
Maneuverability
Innovation

Definitely no...
(at least from my experiences working with Chiara and Nao robots).

[Rick Wagner]

As a design rule of thumb, legs should only be used where wheels won't work. Legs are more complicated, slower, less powerful, and difficult to program. Wheels are simple, fast, and reliable.

There aren't many places where wheels or tracks won't work.

That said, it would still be cool to see a fast legged robot in a FIRST competition. Not saying it can't be done, it's just not for rookies.

[davidthefat]

Originally Posted by Rick Wagner

As a design rule of thumb, legs should only be used where wheels won't work. Legs are more complicated, slower, less powerful, and difficult to program. Wheels are simple, fast, and reliable.

There aren't many places where wheels or tracks won't work.

That said, it would still be cool to see a fast legged robot in a FIRST competition. Not saying it can't be done, it's just not for rookies.

We will see next year in the LA regionals who's team has the Fully Autonomous Possibly legged robot... I am going more toward wheel, but a wheel/leg hybrid sounds cool

[Rick Wagner]

Originally Posted by davidthefat

We will see next year in the LA regionals who's team has the Fully Autonomous Possibly legged robot... I am going more toward wheel, but a wheel/leg hybrid sounds cool

Actually, if you know ahead of time that you'll be walking on a flat floor (where wheels work well), you can do a fairly simple mechanical linkage (one motor on each side driving three legs) hexapod that will scoot around and look impressive. It might not win a competition, but it might get a design award!

[davidthefat]

Originally Posted by Rick Wagner

Actually, if you know ahead of time that you'll be walking on a flat floor (where wheels work well), you can do a fairly simple mechanical linkage (one motor on each side driving three legs) hexapod that will scoot around and look impressive. It might not win a competition, but it might get a design award!

Or some weird robot with a wheel based drive system but also with legs on the outside. That would be so awesome.