Heavy chassis

[radonek]

So I wanted something on wheels to haul fuel from ISRU rig, with a decent sized tank. My problem is that big Rovemax XL wheels are awfuly heavy and TR-2L too small. After some deliberation and with a bit of help from robotic parts from Breaking Ground  I came up with this:

Spoiler

My problem is that wheel suspension goes kraken-crazy in this configuration. I was able to tackle it somewhat by attaching wheel beam a bit off-center and fiddling with a spring/damper override until it became driveable (and as far as offroad capabilities go, it works great) but… it depends on vehicle weight, wheel units tend to rock like crazy and when docked to mining rig it went krakening again. When I set hinges to powered and rotate  until only one wheel in pair touches ground, all problems go away, which makes me think that hinge is not the main culprit here.

I would be grateful for either advice how to make this work, or suggestions of better chassis configuration.

[bewing]

Where is this going to be landed? Generally when the suspension goes crazy, it's because you've got too much suspension (as in too many wheels for the local gravity). Can you remove some wheels, fill it full, then teleport it and test it on your favorite moon?

[sturmhauke]

I used a configuration somewhat like that for a heavy cargo vehicle, used for delivering a base from a shuttle cargo bay to the Munar surface. In addition to the rocker hinge, I added a piston between that and the vehicle body. I also limited the range of motion and turned down the spring and damper settings on everything.

This video is of an earlier version, using mod wheels that I have since swapped out due to bugs. But I kept the piston and hinge arrangement.

 

[king of nowhere]

this one look like a rockomax jumbo 36 ton tank. incidentally, i use the same fuel tank for my rover, and i use 8 ruggedized wheels for it, just like your model. My rover has a few extra funcionalities that raise its weight to 50 tons, still, i never had any problem with suspensions. and that's both with full tank or empty tank, on mun and on minmus equally.

P.S. why are the wheels attached to hinges? i cannot figure out their purpose

P.P.S. i also cannot figure out why your rover has RCS thrusters. i don't see rockets on it to make it fly

[radonek]

11 hours ago, bewing said:

Where is this going to be landed? Generally when the suspension goes crazy, it's because you've got too much suspension (as in too many wheels for the local gravity). Can you remove some wheels, fill it full, then teleport it and test it on your favorite moon?

Will try. So far, I test it unladden on Kerbin, under assumption that lower gravity on Mun or Ike should be roughly balanced by fuel load.

13 minutes ago, king of nowhere said:

why are the wheels attached to hinges? i cannot figure out their purpose

Hinges are unpowered and unlocked so that each wheel pair can follow terrain slope. Ruggerized wheels don't have enough suspension travel length to handle this and inner wheels would come out of grip.  (You can also see terriers on each end for propulsion.)

Spoiler

 

[king of nowhere]

4 hours ago, radonek said:

Will try. So far, I test it unladden on Kerbin, under assumption that lower gravity on Mun or Ike should be roughly balanced by fuel load.

Hinges are unpowered and unlocked so that each wheel pair can follow terrain slope. Ruggerized wheels don't have enough suspension travel length to handle this and inner wheels would come out of grip.  (You can also see terriers on each end for propulsion.)

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while those hinges do indeed look cool, they are not strictly needed, and may be causing the problem. you could try removing them just to see how it goes. i use robotics a lot, but they are kraken bait.

it is also possible that this only happens in high gravity. have you tried this rover on mun? maybe the problems will just disappear.

I failed to notice the rockets at first.