To rove or not to rove

[Warzouz]

In late 1.0.5, I Iook at rover (finally...). I did a Elcano challege around Mun with a derivative of my Doggy rover, and also 50+ km tests on Eve, Duna and Laythe at x4 speed

In 1.1.2, I was wondering about sending rover on far planetary bodies. I tried my Doggy rover (a 2WD powered by 2 RTG). I noticed several points

• Wheels eat much more electrical power than before (6 time more ?).
• Speed is higher on flat groung (35m/s instead if 20m/s on Kerbin)
• The rover is less prone to flipping (that's good)
• The rover is more skiddy (especially when braking)
• Can't get to high physical time warp (even x2 seems to be dangerous).

Have some experience with using rover on planetary bodies ?

Did you tests physical timewarp ?

What tweaks do you recommend ?

How do you manage electrical power ?

[Brainlord Mesomorph]

Still researching new wheel dynamics for my high speed rover tutorial.

I can confirm everything you said. 

There doesn't seem to be a top speed on flat ground anymore (was 50 m/s) but there is this new question or "wheel stress" 

research is ongoing....

[Warzouz]

OK I did a quick test on Mun at x4 with MJ autopilot. it works quite well finally. the rover is MUCH less prone to flip but it's less stable in straight line.

Off course, jumping crater at 20m/s is still dangerous (probably more prone to crash than before - hard to tell).

In the end, the power increase is not an issue because the wheel don't apply power all the time to maintain speed.

 

 

[Geschosskopf]

17 hours ago, Warzouz said:

In 1.1.2, I was wondering about sending rover on far planetary bodies. I tried my Doggy rover (a 2WD powered by 2 RTG). I noticed several points

• Wheels eat much more electrical power than before (6 time more ?).
• Speed is higher on flat groung (35m/s instead if 20m/s on Kerbin)
• The rover is less prone to flipping (that's good)
• The rover is more skiddy (especially when braking)
• Can't get to high physical time warp (even x2 seems to be dangerous).

Have some experience with using rover on planetary bodies ?

Did you tests physical timewarp ?

What tweaks do you recommend ?

How do you manage electrical power ?

Your observations are all the same as mine.  The FATAL instability of ruggedized wheels at even 2x physical warp (and the M1 wheels at 4x) is particularly depressing because it makes long trips take too long to be fun.  Fortunately most mod wheels are more tolerant of physical warp.

As for tweaks, I recommend setting Traction Control to zero.  Traction Control appears to work the same as in real life, decreasing power to those wheels that the game thinks are slipping/spinning.  Problem is, wheels in Unity don't actually turn so there's no actual wheel RPM to measure to reach this decision---it all has to be inferred from other values that are not independent variables.  Thus, the Traction Control system seems to get a false positive when the rover goes up even a slight hill, meaning it decreases power just when you need it most, and thus you bog down on a 10^ slope.  Setting Traction Control to zero solves this problem.

Increasing Friction does what you'd expect, which also entails higher power consumption and greater wheel stress.  However, you need it on really steep slopes (especially just to stop on them, which you'd better do sideways to the slope), when you're not going fast anyway, so the stress isn't a problem.

As for the VASTLY increased electrical consumption, that's not as bad as it sounds.  As Newton dictates, it takes more power to get moving but once up to speed on reasonably flat ground, power consumption decreases a lot, so you end up needing way less power to keep moving at full speed than you needed to start.  But you need all the power you can get to go up hills.

So, if you stay on reasonably flat ground, you can get by with a few hundred battery and enough EC/sec generation for maybe 1/2 the max consumption of all your wheels.  The battery provides the extra oomph to get going but, once up to speed, the power required goes down enough for the generation to keep pace with.  However, this set-up will make climbing big hills very slow due to frequent stops needed to recharge the battery.  So for that, you either need a really big battery or enough generator to supply all the wheels at max consumption.

As to where the EC comes from, solar is of very limited usefulness due to the limited surface area on the rover to mount sufficient OX-STAT-XLs, the inability to use Gigantors in atmospheres while moving at any speed, and the general anemia of solar panels beyond Duna (or on the surface of Eve).  The smaller panels need not apply even where the sun shines.  So that pretty much leaves fuelcells.  Specifically, the big fuelcell array.  Which means your rovers now need LFO to go any distance, and will need refueling afterwards.  There's a mod fuelcell that uses LF and IntakeAir which is good on Kerbin and Laythe but useless everywhere else.  However, given that you can't physically warp much if at all with a rover these days, you have much less incentive to make long trips anyway.

Bottom line for me is, all this makes very little difference in how I use rovers.  I'm not the El Cano type of guy.,  I use rovers for limited purposes, such as prospecting for the best spot of Ore in a relatively small area that I already know from orbit (thanks to SCANsat) is pretty good.  Or driving around the neighborhood of my base.  Or building the base.  But I've never liked roving for exploration even when you could circumnavigate planets at x4 physical warp on a handful of OX-STATs (the small ones).  Why drive when you can fly?  Roving only beats flying where there's high gravity and no atmosphere, such as Tylo and (in OPM) Slate.  Everywhere else, I build either airplanes (if there's atmosphere) or hopping landers (where there's low gravity and no atmosphere).

 

 

 

[Jaeleth]

I have a long experience with rovers. I use them on all planets with gravity equal or higher than the Mun. but I am still using 1.0.4 for several reasons, hope to be able to migrate to 1.1.2 soon, but I am well aware of rover... Issues, in this late version, that is, actually, the main reason why I haven't migrated yet...

Rovers (used directly or as mobile bases) are the only practical way to effectively explore high gravity worlds, they are particularly usefull for building mobile mining bases which can attach to your larger craft and refuel them, among many other things. 

But... There is one secret... The ONLY way for rovers to be of practical use is to have mechjeb installed and use rover autopilot. The game time required for, say, an 80km land voyage (at safe speeds) is between 1hr to 2hrs if your computer has a 1:1 frames per second ratio, if not, it will be longer, so, mechjeb it all the way, watch a movie or go eat lunch, and remember to stop the journey and save game from time to time...

(note: no time warp, using time warp shortens the time, of course)

 

before using mechjeb rover autopilot I used to have many accidents since I literally would sleep at the wheel and go full throttle over a cliff....

 

 

Edited May 18, 2016 by Jaeleth

[bewing]

8 hours ago, Geschosskopf said:

As to where the EC comes from ... the inability to use Gigantors in atmospheres while moving at any speed

I never had any problem using Gigantors at speed. I just tested one on a plane on Kerbin, at sea level. It didn't break off until 73 m/s. I cannot imagine this ever being a problem on a rover.

[Geschosskopf]

3 hours ago, bewing said:

I never had any problem using Gigantors at speed. I just tested one on a plane on Kerbin, at sea level. It didn't break off until 73 m/s. I cannot imagine this ever being a problem on a rover.

Well, that's news to me.  Wonder when that changed.

[Warzouz]

Hmmm, fantastic ! One of my rover wheels blew up due to "overstress"... but the rover was in space...

OK, using cheat menu, I turn the part blow into 2 tires flat. Sadly, it's a rover probe. Maybe I can edit the save file.

PS : the rover wheels wasn't touching anything and I loaded the scene at least 5 times.

Edited May 18, 2016 by Warzouz

[bewing]

Was it inside a fairing?

[Warzouz]

19 minutes ago, bewing said:

Was it inside a fairing?

Nope, the fairing was dropped into Kerbin atmosphere. The wheels were destroyed in Eve SOI.

[Jaeleth]

15 hours ago, Warzouz said:

Hmmm, fantastic ! One of my rover wheels blew up due to "overstress"... but the rover was in space...

OK, using cheat menu, I turn the part blow into 2 tires flat. Sadly, it's a rover probe. Maybe I can edit the save file.

PS : the rover wheels wasn't touching anything and I loaded the scene at least 5 times.

In that case you may find the Hyperedit mod usefull. Some say it is the "best cheating mod" in ksp, and it probably is, but I do not use it for cheating... I use it to fix things when the game cheats on me

unfortunately the developers are taking some time to adapt it to 1.1.2... You'll have to wait.

anyway, when something "buggy" happens 2 years into a mission to anywhere and I cannot reload, for some reason, I kill the affected ship (carefull if it has kerbals in it) build another one and hyperedit it to the same place the other was, in seconds, editing the game file and refunding me the value of the lost ship... Resuming game as it were ans as it should've been, without the bug...

 

 

 

[Warzouz]

What I did

• Alt-F12 and use the "no crash cheat"
• Decoupled the 2 rovers (only one has the bug)
• Edit the save file and change the 2 tires to undamaged
• Remove the cheat.

Rovers are OK now.

I would have use HE.

 

[Warzouz]

I'm currently testing Eve roving.

the rover is a 1.2ton powered by 2 RTG. I use MJ autopilot.

I set the speed at 25m/s and the pysical timewapr at x3. it's quite freaky (the wheels are jittery) but after 10km no blow.

I removed the friction autocontrol and set it to 1.0 to avoid sliding.

To avoid electrical problem I set infinite electical power.

 

It's surely not as smooth as it was in 1.0.5 and much less enjoyable.

Edit : a tire just blew.... Wheel stress never went over 5%...

Edited May 19, 2016 by Warzouz

[KerikBalm]

My eve rover is much much much more flip resistant than before... it also skids all over the place.

I was driving it on a slope near the shore... and it started side slipping and ended in the water... the wheel traction was terrible ... at least in eves 1.7 Gs...

[Warzouz]

9 hours ago, KerikBalm said:

My eve rover is much much much more flip resistant than before... it also skids all over the place.

I was driving it on a slope near the shore... and it started side slipping and ended in the water... the wheel traction was terrible ... at least in eves 1.7 Gs...

On Eve, I was slinding on a 4° slope... I set the friction from auto to override : when your speed is very low, auto friction goes to 0.2 which seems to be not enough to stop sliding. I set the friction to 1.0 and the rover stopped sliding.

The other issue is dampers. At x1 or x2, it's quite OK, but try going to x3 or even x4. Even without moving, the rover starts jumping all around.