Rover design

[sparty48]

I was just looking for some tips for a light rover to take to the mun. Where should I put the COM? Solar panels or otherwise?

[Nasakev]

Well, what kind of rover are you looking for here? Something small, Jebediah's First Rover style? Have you landed rovers on the mun before? There's a ton of variation in rovers.

[toomuchbrew]

Manned or unmanned?

Edited November 2, 2013 by toomuchbrew

[capi3101]

General principles - build it low, build it wide, include a reaction wheel, encase the critical bits in structural panels and girders. SAS on when you're not turning and either drive in docking mode or remap the keys so that you're using lateral controls, not rotational. Rovers do not necessarily have to be built off of rovemates; the more successful rovers I've built didn't include them and if electrical storage is a concern, add Z-100 packs. Keep all that in mind and you can build pretty much whatever you want.

Specific questions you asked - generally the CoM works best as long as it's somewhere along the rover's centerline axis (running from front to back). If that's not centered then steering it becomes problematic. The closer you have the CoM to the exact center of the rover, the easier it is to launch it to Mün; this can be off-center but you'll either need to add a counterweight on whatever delivery system you develop.

I've seen rovers that use panels and I've seen some that utilize RTGs. I prefer RTGs myself for rovers as they ensure that I won't completely run out of juice while driving at night (and trust me, I've done more than my fair share of night driving; a scary prospect on Mün). You can enclose RTGs in with structural panels and still have a drivable rover when it flips over; the same cannot necessarily be said of solar panels. That said, solar panels are of course lighter, and with good placement you can keep them relatively well protected and still functional. I've seen some successful designs that included solar panels, and if you're using ion engines for downforce they become essential.

[Tw1]

If you can, put your COM low. This will help with stability. Placing your wheels so they are even around the COM also helps a lot.

Rovers vairy a lot, but these are general tips. Also, avoid placing wheels in a way that the side that looks like it goes down, doesn't point down. They won't work well.

[toomuchbrew]

I've made a decent rover with deck plates with a gap inbetween them where i put all the electronics and it worked well and was pretty light. It didnt perform that well on minmus due to being so light and without any downforce. it's on one of my videos in the link in my sig

[Leatherneck]

General principles - build it low, build it wide, include a reaction wheel, encase the critical bits in structural panels and girders. SAS on when you're not turning and either drive in docking mode or remap the keys so that you're using lateral controls, not rotational. Rovers do not necessarily have to be built off of rovemates; the more successful rovers I've built didn't include them and if electrical storage is a concern, add Z-100 packs. Keep all that in mind and you can build pretty much whatever you want.

All of these are good points.

Also, test them on Kerbin. If it flips or does something crazy there (like the grassland), it will be 100x worse on Mun and Minmus. Of course, I've also had super stable rovers on Kerbin that freak out on Mun, but that's because I didn't widen or lower the CoM enough.

[keoki]

Sorry if this is a silly question, but when I search for how to remap keys, all I get is people saying you should remap your rover keys. But no one will offer a link on how to do it so searching for remapping is useless. I found a great page with rover hints, but what good is a hints page without links to information for following through on the hints??

http://www.reddit.com/r/KerbalSpaceProgram/comments/1lvf2v/rover_tips/

My rover worked great on Kerbin, but as soon as I got it to a planet with lower gravity, suddenly I realize just how incompatible SAS and wheel motions are when on the same keys. I was wondering about that before, but suddenly became painfully aware of how messy that linkage was. So I found lots of people agree, and the solution is agreed upon as well... but I guess no one expects their discussion of the remappings to be read by someone trying to figure out how to do a remapping...

I found the key bindings page, but it left me with even more questions, like how do you change modes, as it seems the same keys do different things in different modes, in addition to operate dissimilar systems such as rudders, wheels, jets, and reactions wheels.

It's pretty amazing that I can complete a single flight with nearly 1000 points worth of science, and I can't drive a darn rover a couple of clicks without blowing up, or rolling it real good... I tried a lot of different things for bumpers, roll cages, self-writing mechanisms... The best anti-explosion bumpers so far is some extra wheels. With a big tumble, using the wheels that look air filled, I frequently pop a tire, turns out you can fix blown tires with a right click menu. So my most robust rover so far is a capsule on a reaction wheel on a rover base, and the thing is covered with solar panels, some batteries shoved into the capsule walls with only the LED's showing, several antennas (so I can loose a couple when the rover rolls). a couple girder segments to protect soft parts of the capsule that get hit on rolls a lot, and wheels all around to protect bits that might snap off in a roll. I tried landing struts at first, but their impact tolerance is very limited, they just snap off if the thing tilts. The wheels and girders have very high impact tolerance, and I have some struts at the corners to keep the capsule from snapping off when the chutes deploy. But keyboard remapping so that RCS works for me rather than against me, would let me leave half of this stuff off, and have a roll-free rover with a lower mass, and a lower center of gravity.

While I wrote this I designed a new rover that doesn't tip over, but I still need to remap the wheels...

[700NitroXpress]

Check this little guy out for inspiration. It has landing legs, vertical take off engines, seats 4 Kerbals, has an RCS system, dual rear engines for long term movement control and boost for getting up steep incline hills.

[Tommygun]

You can make very small and light rovers out of the M-Beam 650 I-Beam.

I made these back before the Command Seat part became available, so all those hand hold parts aren't needed.

This one runs on a RTG, but you can line the floor with those small solar panels.

You also don't need lights on small rovers like this, as you can have the Kerbals just turn on their helmet lights.

There are many possibilities.....

Edited November 16, 2013 by Tommygun

[keoki]

So how do I remap my wheel motion keys?

[capi3101]

Personally, I find you can just put your rover in docking mode and save yourself the trouble of having to remap by driving around on WASD. That said, I'm pretty sure to re-map your keys you just do it under Settings off the game's main menu. One of the options there is for controls unless I'm mistaken.

[Deadweasel]

To switch control modes, use the buttons on the small display at the bottom left of the screen. To switch from flight to translation mode and back.

A couple more tips:

Four-wheeled rovers can flip out while braking or turning. You can decrease the chances of these happening by disabling the motors and steering in select wheels. Four wheeled turns can cause the vehicle to flip at-speed, so try locking the steering on the rear wheels if this happens to you. Steering will be slower, but it's just a matter of planning a little farther ahead when you want to change direction.

[astropapi1]

There are many possibilities.....

Gimme gimme?

[Rusty6899]

Light rovers tend to be a bit sketchy on bodies with low gravity, such as Mun. I normally build fairly heavy rover, and ensure a low centre of mass and as large a width/height ratio as possible. You can pretty much test any rover design on Kerbin, but a major problem comes with finding a way to land your rover and jettisoning the engines that you used without damaging it. Also it is important to keep your speed as low as possible when driving your rover on the Mun - just because you can max it out to 20m/s doesn't mean it's safe to drive it that fast. My rovers are all liable to break apart when I drive very fast, particularly when going through a change of gradient.

[zekes]

My favorite little rover is this one:

It has one SAS pod in the bottom for stability. It's amazing how well that works.

[keoki]

I have a really nice rover designed, but I really need to decouple the wheels from the flight controls. I don't just want to move the flight controls to other keys, I want the wheel controls to not be flight controls.

One issue I am having is that during construction, the parts are forced rto fit together in a manner that my rover's frontside is at a 45 degree angle to flight geometry. When you move the wheels for the first time they seem ok, but after running for a while, the wheels start to become directionally unstable and jitter left to right while turning. Usually it is just one wheel at a time, but it cannot decide which way to turn. After running for a while all of the wheels start to jitter in the turns. So you can try to turn right, and sometimes you go right, and sometimes you go left. This rover is very stable, but with unstable turning action in light gravity, it will still go sailing.

If I could actually define left and right for each wheel, and bind those directions to keys, separate from attitude control, I would probably cure the jitter. I think the jitter is from the off-axis assembly that I am forced to use. I see stabilizer fins jitter in the same manner during flight, depending on where they are connected, and what flight control is trying to do. When flight movements don't cleanly translate to an obvious physical motion, the shifting between the two possible motion directions appears to be how the program deals with the ambiguity. I'll continue to try other construction methods to see if I can align the axis, but I shouldn't have to if I could define the motion of the wheels myself.

Thanks for the clue on the docking mode. It didn't help me solve my steering jitter problem, but it pointed me in the right direction to understand what others are talking about when they talk about docking mode.

But to be clear, I don't care what keys do what. But it would be nice if I could leave sas on and use it with the attitude controls to help the rover be stable during high-speed risky driving, while independently with different controls drive the wheels. People are talking about doing that, so I know it is being done... Ok, so I looked in the settings again, this time after exiting the game, and I can see the places to configure the controls. I looked in settings once before, but I guess it was during the game and it didn't show this page. It also has axis bindings, so if I can figure out how to use that, I can probably fix my turn jitter problem... Excellent!

[Tommygun]

Gimme gimme?

I forgot where I parked them.....

I have at least 21 installs of KSP across 8 versions on my back up hard drive.

It's like trying to find the right silver SUV at the mega mall.

[wasmic]

The tracks from the Caterpillar Tracks mod work quite well for rovers.

[Tank Buddy]

Change rover throttle to up arrow and down arrow and steering to left and right arrow. This way you can independently manage torque and motion. Also, If you are still relatively new to docking and haven't gotten used to the controls, I highly recommend changing the translation controls for RCS to the arrow keys and Lctrl and Lshift. I find in much easier than memorizing the letter key. Hope this helps.