[TC16] Marsupial

[MangaNOID]

Thanks guys, 

almost ‘finished’. I know how to improve this but no parts or time. It certainly presents some challenging mechanical issues in LEGO (that I haven’t really overcome properly) but maybe it’s just a stupid crazy idea that only belongs in a sci-fi world 

the only other thing I found close to this in real world is a straddle carrier on the docks.

https://en.m.wikipedia.org/wiki/Straddle_carrier#/media/File%3AStraddle_carrier_from_Port_of_Chittagong_(05).JPG

 

[MangaNOID]

Marsupial: failed

I have entered TC16 but only in the spirit of contest. Last is better than withdraw.

-there is way too much backlash/windup through the steering and it does not work.

-the backlash creates loose steering at the wheels so this can wander when moving it.

-the pneumatics are not strong enough for the weight of the vehicle so when the steering wanders the legs collapse with the direction of the wheels. Linear actuators could fix this as they are more rigid than pneumatics but I do not have enough of them to try.

-worm gears on the small turntables at the wheel could prevent wandering by tightening up the wheels.

-the legs are far to unstable in the lateral position and one small rock or LEGO brick can twist them backwards out of alignment.

In the video I did everything manually as it just was not working. I do not try to hide the failure of this model so the video is not great. at least i kept quiet when filming instead of swearing and laughing at it.

hopefully one day I can build something that is not beyond my capabilities 

The concept remains interesting and I may dabble with this near future on a smaller version...maybe

 

 

 

 

 

 

[1gor]

Idea is very cool and it is not your guilt that pneumatics work that way. Perhaps you should build it smaller scale so it could be more sturdy ...

The point is to push limits so you can develop and learn something new

[Seasider]

I hope you're still actually entering it. So what if the functions don't work perfectly. It looks REALLY great.

[syclone]

Sad to see that it didn't work quite as intended, but the concept of it is very unique nonetheless. And it looks taken straight out of a sci-fi futuristic movie) 

[sirslayer]

I wonder if the Eurobricks Gods can grant us our prayer and give us a few more days from the deadline...  

[ArsMan064]

It really needs motorization

[MangaNOID]

2 hours ago, I_Igor said:

The point is to push limits so you can develop and learn something new

I feel like I have done that in the last two MOC's which is good to do you are right you learn the limits of the media, but I need success on a build sometime soon! 

40 minutes ago, Seasider said:

I hope you're still actually entering it

I am, just because someone needs to come last 

26 minutes ago, syclone said:

And it looks taken straight out of a sci-fi futuristic movie

Tha'ts the only positive I see in this is creative expression 

16 minutes ago, sirslayer said:

I wonder if the Eurobricks Gods can grant us our prayer and give us a few more days from the deadline

you mean to try and fix this up? no way man. I'm ripping it apart right now 

12 minutes ago, ArsMan064 said:

It really needs motorization

having a think about it the only way I see to motorise is to have a motor in each leg for the steering to limit backlash, and another motor in each wheel hub for drive.

the only problem with that is steering angle and scrub radius type of thing if that is the right terminology as the wheels are so far apart from each other (left to right) that a large difference of steering angle is needed when turning (ackerman stuff). it can be done through many gears with central drive like I was trying before, but then you get into backlash again over so much distance and sets of gears... Oh! I am learning from these failures quite a bit actually  

[shadow_elenter]

Hey man,

It's always sad to se a project fail.
Having said that, I have enjoyed following this topic  A LOT!
I appreciate your sportsmanship as much as the fact that you're trying something radical and it looks amazing!

I'm afraid you won't win first prize, but your a winner in my book!

[Shiva]

What about a locking device? So the ... legs? get locked when in transport mode?

For advice on steering? no clue, I'm not an expert.

Mars? Gravity is... about 38% of that of Earth, source wikipedia https://en.wikipedia.org/wiki/Gravity_of_Mars . And this is tested on earth gravity, so no wonder if the vehicle might collapse.

Edited August 6, 2019 by Shiva

[MangaNOID]

6 hours ago, shadow_elenter said:

It's always sad to se a project fail.
Having said that, I have enjoyed following this topic  A LOT!
I appreciate your sportsmanship as much as the fact that you're trying something radical and it looks amazing!


I'm afraid you won't win first prize, but your a winner in my book!

Thank you for the Love!  I'll keep trying for sure. just a bit frustrating when things don't work out but in reality one could carry on with this idea and keep trying to make it work. Not for the contest of course.

Its a bit embarrassing to fail so hard amongst fellow enthusiasts but  'on the internet, no one know's who you are' 

 

5 hours ago, Shiva said:

What about a locking device? So the ... legs? get locked when in transport mode?

A locking device is a good idea but I really wanted this thing to travel along at any height. when i have 4 LA's I may try this setup again as that is where the success is I think.

there are some other really interesting effects of this setup if done right like moving one leg up at a time to go over a large rock whilst keeping the chassis stable...kind of like active suspension.

5 hours ago, Shiva said:

Mars? Gravity is... about 38% of that of Earth, source wikipedia https://en.wikipedia.org/wiki/Gravity_of_Mars . And this is tested on earth gravity, so no wonder if the vehicle might collapse.

no excuses please 

[Shiva]

1 hour ago, MangaNOID said:

no excuses please 

No no, that is no excuse, that is reality :D