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THIS IS THE TEST SITE OF EUROBRICKS!

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Posted (edited)

This is a project MOC I've been working on during my evenings and weekends for about 5 months. I really tried to cram in all the features I thought would be cool. The rover weighs just short of 3kg, has 11 motors, over 4 meters of pneumatic hose. It's controlled with two remote controls. Getting all those features with limited parts and tight space constraints was a huge challenge

 

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Main Functions:

  • 4W Drive, Steering
  • Switch between crab and 4-wheel steering
  • "Solar Panel" unfold/fold
  • Crane up/down, left/right, extension/retraction, "pincer"
  • Cargo bay door open/close
  • Pneumatic airlock
  • Fully RC

Other small stuff:

  • Rotating satelite dish
  • Detailed cabin
  • Independent suspension on all wheels
  • Two servos each control two pneumatic functions

Design process

I started with the chassis, and moved on from there.

Driving and steering worked a lot better before it put on all the weight! I had to plan ahead for everything I wanted to add and how it would fit together, which got really complicated so I had to start drawing out the connections. I basically had one drawing for how the modules physically fit together, one for the pneumatics connections, and one for the electronics. Even things like the lengths of the cables would determine which battery I could hook them up to, and every single battery connection and remote control button is in use.

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I used a few clever tricks to give motors more than one function. For example, each pneumatic pump is also a switch, depending on the direction it spins, using a design I borrowed from youtube. Each servo motor controls two switches each, because by design it was possible to make functions opposites of each other. The pneumatics engage in order of easiest to most difficult, so there are some rubber bands to set the order of activation. E.g. the up/down motion of the crane is paired with the storage lid.

Improvements

There are a lot of possible improvements that could be made, but I'm eager to move on to the next project and I'm happy enough with it already. Here's what I would change:

  • Less functions overall. My line of thought when I started this project was "ooh I'll make everything with pneumatics because they're cool, and make it all remote control, and add crab steering because why not, and etc etc". But then it really dragged on forever. Next time I'll keep it small and simpler. Especially now that I've ticked most of my idea boxes
  • No / fewer remote-control pneumatics switches. I did it, it's possible, but it takes up a lot of space and often doesn't work so well
  • More robust steering (and no crab steering). The crab steering takes up like a third of the space and adds a ton of weight, and doesn't work very well. After trying it myself, I'm even more impressed by Madoca's shaman
  • If a vehicle, all wheel drive
  • For something so heavy and high torque like this, i'll definitely keep each driveline on separate batteries. Having two drivelines (left and right) improved the performance a lot, but since I needed every single battery output I moved all motors to the same battery, which killed performance
  • I'll probably avoid exteriors and paneling — I'm not that great at it and it just adds weight

Inspiration

The idea and inspiration came from Eurobricks mars mission contest (ZeroBricks, Samolot, Kubic5), Simon stallenhag's artwork, and image searches for mars rover concept art

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I'll take more (and higher quality) pics of it as I take it apart, just need to wait for a free day with good lighting! Happy to answer any questions! Thanks for reading

Edited by teetertater
youtube embed
Posted

Cool Rover and great pneumatic functions. (I love pneumatics:wub:).

I don't think remote controlled pneumatic switches and crab steering are bad, do they work so poor? Without those it would still be a fantastic rover to drive on mars.:thumbup:

Posted

Very cool!  Thank you for sharing it.  And the bank of old-school printed display bricks brings back pleasant memories.

What do you think was the issue with the crab steering?  Was the pivot point too far from the wheel center, was it a structural issue, or something else?  Those portal axle parts are great for ground clearance but I could see them being tricky to steer smoothly.

Posted

 

 

33 minutes ago, The01 said:

Cool Rover and great pneumatic functions. (I love pneumatics:wub:).

I don't think remote controlled pneumatic switches and crab steering are bad, do they work so poor? Without those it would still be a fantastic rover to drive on mars.:thumbup:

 

13 minutes ago, Hrafn said:

Very cool!  Thank you for sharing it.  And the bank of old-school printed display bricks brings back pleasant memories.

What do you think was the issue with the crab steering?  Was the pivot point too far from the wheel center, was it a structural issue, or something else?  Those portal axle parts are great for ground clearance but I could see them being tricky to steer smoothly.

Thanks! :) 


I think the issue with both the RC pneumatic switches and crab steering was that I tried to do too many things at once and didn't focus on making them 100% robust. So e.g. combining multiple switches onto one servo makes it frequently not work as expected (only one side activates, the elastics don't bring the switch to the centre, etc etc. But these are issues with my execution, perhaps someone can come up with a better design! Perhaps I should also note that the video was heavily edited with multiple takes, IRL it seldom works so smoothly.

With crab steering the main issue was the gears sliding back and forth across their axles and creating leeway over time. Then since I piled so much stuff on top of the steering system it became a nightmare to repair. I basically have to do surgery to put the gears back in place haha (without taking half of it apart). The other big issue / design flaw was having to align the wheels perfectly prior to switching back and forth between steering modes. This is quite difficult with the XL motor and my gearing ratio -- I geared it so steering would be relatively fast, but that means it's really hard to precisely align all the wheels in a row. I think this design was okay when I started, but should've been more robust with all the rest on top.

Posted (edited)

Very nice! I love the complexity, especially in that crane arm. I also never really thought about how much harder it is to add crab steering to a 6-wheeled vehicle. Usually just adding an extra motor for the rear axle can make 4-wheeled crab steering work well, but it looks like that wouldn't work for a 6x6.

I'm also using those MouldKing pneumatics (That is what you have, right?) and have been very pleased with their performance and price.

1 hour ago, teetertater said:

I tried to do too many things at once and didn't focus on making them 100% robust.

That's me on practically every MOC I make :sceptic:

Edited by 2GodBDGlory
Posted
32 minutes ago, Zerobricks said:

Interesting design, glad to help with the inspiration. Lots of functionality in a small model, though it can be improved, so it's more reliable and more stiff.

Thanks again ;) Absolutely agree. 
Btw I really loved your and the other submissions for TC16, definitely my favourite contest! Also impressive how quickly the submissions were done, no way I would manage in that time restriction haha.

2 minutes ago, 2GodBDGlory said:

Very nice! I love the complexity, especially in that crane arm. I also never really thought about how much harder it is to add crab steering to a 6-wheeled vehicle. Usually just adding an extra motor for the rear axle can make 4-wheeled crab steering work well, but it looks like that wouldn't work for a 6x6.

I'm also using those MouldKing pneumatics (That is what you have, right?) and have been very pleased with their performance and price.

That's me on practically every MOC I make :sceptic:

Thanks! Yeah the crab steering was definitely tricky, I tried several designs. Reddit user pattspatt recommended this system for switchable crab steering, but I haven't tried it yet
https://rebrickable.com/mocs/MOC-8316/ErikLeppen/five-axle-crane/#details

Mould king motors, pneumatics, controllers, some pieces, yep :) Definitely agree, I wouldn't be able to afford any of this otherwise ha! My only gripe with MK pneumatics is that two of the pumps broke where the plastic meets the metal, but fortunately I was able to fix them with super glue. Loy from yourwobb offered to replace them free anyway with my next order.

>That's me on practically every MOC I make :sceptic:
Hahaha same. On this one I just wanted to get it over and done with, otherwise it would've taken me a year :laugh:

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