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What are the basic needs of a rover?


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Bare minimum to function:

- 4 wheels (footnote)

- battery

- some sort of battery recharger - solar panel or RTG.

- a command core.

- whatever structural girders are needed to tie them all together.

Good ideas to enhance it:

- self-righter mechanism - either landing legs on the top that flip it when activated, or an upward-facing tiny engine that can be thrusted to flip it.

- kerbal-carrying seats. (a kerbal passenger can get out and repair broken wheels).

- design it as flat and low as you can to make it less likely to flip over in low-grav environments.

(footnote: Getting 3-wheel rover arrangements to work is hard because none of the wheels are designed to be attachable from above or between two forks - they're all defined to be mounted on one side, meaning you need a lopsided offcenter arrangement to get a single wheel centered.)

Advice for the VAB:

- The symmetry settings are hard to use for putting wheels on - often not letting you put the four wheels on correctly unless you do it manually. Placing manual wheels makes it very easy to make a lopsided wobbly lander. Be as careful as you can trying to keep it manually symmetrical. One hint: although you can't use 4-way symmetrical mode, you can use 2-way symmetrical mode to place one pair of diagonally opposite wheels, and then the other set of diagonally opposite wheels.

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Bare minimum to function:

- 4 wheels (footnote)

- battery

- some sort of battery recharger - solar panel or RTG.

- a command core.

- whatever structural girders are needed to tie them all together.

Good ideas to enhance it:

- self-righter mechanism - either landing legs on the top that flip it when activated, or an upward-facing tiny engine that can be thrusted to flip it.

- kerbal-carrying seats. (a kerbal passenger can get out and repair broken wheels).

- design it as flat and low as you can to make it less likely to flip over in low-grav environments.

(footnote: Getting 3-wheel rover arrangements to work is hard because none of the wheels are designed to be attachable from above or between two forks - they're all defined to be mounted on one side, meaning you need a lopsided offcenter arrangement to get a single wheel centered.)

Advice for the VAB:

- The symmetry settings are hard to use for putting wheels on - often not letting you put the four wheels on correctly unless you do it manually. Placing manual wheels makes it very easy to make a lopsided wobbly lander. Be as careful as you can trying to keep it manually symmetrical. One hint: although you can't use 4-way symmetrical mode, you can use 2-way symmetrical mode to place one pair of diagonally opposite wheels, and then the other set of diagonally opposite wheels.

What about the landing gear as the third wheel?

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What about the landing gear as the third wheel?

It's possible, but aircraft landing gear don't steer, as far as I remember. So it works for a wheel in back but would probably give very funky steering physics if it was a wheel in front (where only the back wheels steer).

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Oh, and another important thing for driving the rover: The maximum speed listed in the assembly building for the wheels is an outright lie. For example, if it says the max speed is 60 m/s, and you manage to make a rover stable enough to actually not flip over at high speed, you'll find that your controls utterly stop responding altogether (W and S keys have zero effect on your speed) long before you get to 60 m/s, and long before the wheels actually break. There seems to be an unpublished, un-mentioned super secret max speed that's quite a bit less than what's listed: A max speed at which the controls stop doing anything and you're helpless to reign in the speed if it's on a slight slope. I've found that for the ruggedized medium sized wheels, it's really about 25 m/s or so where the controls have no effect at all, even though the max speed is listed as 60 for them.

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Magic fairy dust, the more the better. Otherwise, it WILL flip over. And your self righting mechanism will explode (or fall off) on impact.

More seriously, drive slowly to avoid flipping over. I've found that if you keep the speed under 0.0m/s the thing almost never flips over.

Even more seriously, your rovers will flip over. Bring two.

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here's the smallest non-lame rover I've made:

u0FxJ2w.png

I could ditch the communotrons, lights and sensors and it would just be: Okto2 probe core, probe battery, solar panel, 2 cubic octagonal struts, 4 dinky wheels.

The battery depletes fast once it gets rolling as it never gets full sunlight and slows to a crawl when it's empty so you have to stop and timewarp till it charges.

I made a nuclear version with an RTG under the bottom, with 2 RTGs it can run at full blast without depleting batteries.

It's super stable, and can flip itself with the okto's reaction wheels, I've only broken 1 (out of about 12 landed) while driving, and that was down a near vertical cliff, I made it halfway down then made a mistake and tipped it a bit too much. It also only needs a oscarB, a torus and a 48-7S to get it down onto the mun.

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Rovers need a command authority part (pod, probe core and/or seat), batts, a way to recharge the batts, and wheels. That's all that's fundamentally needed. I recommend encasing the crucial crap in structural panels and girders (i.e. parts with high impact tolerance). A Reaction Wheel (for stability control) is always a good addition. For low gravity worlds, a system for adding downforce is also recommended; I suggest ion thrusters for that purpose. For all rovers, build it wide, build it low, have SAS on, and drive around in docking mode (or re-map your keyboard - you want to be using controls for translation, not rotation).

Obligatory screenshots of the Hellhound 7 on Minmus:

gUcC3gM.png

4WXONu0.png

I've had one of these flip over on me once - and I was able to upright it again on the probe core's torque alone: an OKTO2.

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With subassemblies in 0.22, you'll be able to build rovers in the SPH using the more suitable symmetry there, and then transfer to the VAB. Looking forward to this!

You've always been able to do this, you just had to manually copy over the craft file from the SPH folder to the VAB one.

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This thread has encouraged me to try out alternative rover types, here's the first.

SRB-powered rocket sled. Capable of roving a few hundred yards from its start point, then stopping dead and running out of charge. Prone to flip on rough ground.

I tried without the beam, with just Sepratron and QBE, but couldn't get it to survive intact.

P8wqzPm.png

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