Rover problems and surface navigation

[Chik Sneadlov]

 

How do I navigate when on the ground, like when I'm driving a rover? Does it help to put the nav ball on surface?

How do I know which way I'm going? I tried putting a node on a previous landing site and then setting that as a target, but when I use the autopilot to set it to target, it tends to pull the rover off it's wheels. It seemed happiest when I was driving away from the target even though I'd selected target. Mind you it wasn't 180 degree to the target that I was traveling. It was some other odd angle. I probably should mention I'm at the bottom of Minimus as best I can tell. The south pole. Not the center, but near it. 

I left my pilot in the rover after breaking off all the solar and running out of electricity and that thing kept picking up speed. It was going about 24 M/sec just before it had some kind of catastrophic problem. This is just on wheel idling power. How do they explain this in a simulator. You've got some kind magic force that propels you across an entire planet with no fuel being used. I dont think it was going downhill. I don't believe that any vehicle would handle as bad as a KSP vehicle on one of these planets. 

The main question -

I landed near a previous landing site. I thought I'd visit the pilot and maybe switch with her and see her rover. I couldn't figure out how to get there. It was only about 5 km. I thought of some complicated, inaccurate ways involving the sun or my current trajectory, but it seems like there should be some simpler way of finding old space wrecks.

The rovers behave oddly on the moons. What is the best way to tame this beast?

Did I mention that the other day I landed a 100 meter tall rocket on Minimus and it slowly fell over but stayed intact? I then detached the rover and moved it out of the way and eventually got back in the huge rocket and took off from a horizontal position on the surface and made it back to Kerbin. I was close enough to walk to the space center in daylight. 

The big rocket scraped along and I ran out of gas and had to start up the next stage which gave me a little bit of angle to the ground. Of course on Minimus with a little speed you're going to be airborne for a long time so I got a little more perpendicular and gave it more thrust and pretty soon I was on my way home. 

I'm going to build a ball shaped cage rover with me and all the vitals on the inside. I'll put wheels all over the outside so that when it hits it'll be partly absorbed by the shocks and I won't have to concern myself with pitch and yaw anymore. 

If I put more wheels on a rover does it have more horsepower and go faster? Does it have better traction. So far I've been using 4 wheels. 

 

 

[Zhetaan]

It reads as though you have a few problems with your rovers.

First, don't set your navigation to target.  The autopilot assumes that you're in space and have three dimensions of rotation; it doesn't know that you can't travel through the centre of Minmus to get to a destination on the other side.

Second, the navball is going to assume the same orientation as the current control point:  this means that if you, for example, have a command pod sitting upright on the ground, then the navball will be oriented so that up is also forwards.  This is fine for flying but does not work for overland travel; you'll need either to use creative rover design or else to place a small docking port or some such on the front of the rover so that you can right-click it and select the option 'Control from here', which will reorient the navball so that your heading is forwards.  On rockets, you want the navball when you first begin to have only blue visible; on rovers, you want the navball always to have blue on top and brown on the bottom (that's the function of those colours; they serve as an artificial horizon).

Third and last, you should be certain to deactivate reaction wheels in your rover or else to bind separate rover wheel controls from the attitude controls; the default has W serve as forwards but it also tries to pitch your rover over its nose.  D by the same effect is both 'turn right' for the rover wheels and 'roll right' for the reaction wheels.  I prefer to bind my keypad for rover wheels; 8-4-6-2 serve the same purpose as W-A-S-D but without involving reaction wheels at all; I also use 5 as an alternate brake key.

As far as rover design, the main reason to add more wheels is to reduce the load on them; in some cases, more wheels add to the trouble without adding much benefit.  It depends on your design.  Honestly, if you have enough stuff on your rover that it breaks wheels, you're more likely overloading the design than anything else.

Navigation ought not to be so difficult; set your destination as the target and it should give you a marker--especially if you're only 5 km away.  I suspect that the reason you had so much trouble getting there was because of other issues I pointed out above, such as the reaction-wheel/rover-wheel dual binding.

Edited December 18, 2017 by Zhetaan

[Chik Sneadlov]

New prob. New ship and modified lander. I've run out of conventional fuel and all I have left is those nuclear decay things to produce electricity for my Xenon powered ion engines. I have lots of them. Anyhow, I mounted the lander on top of the rocket with the rocket blasts facing down, but for some reason when I set up a maneuver node, I'm burning in exactly the opposite direction that I wanted to hit with my target. There is no thing to aim for with the autopilot that is the anti maneuver. 

Its probably something to do with rotating the lander too many times in one of the directions. Its confused the computer. Or wait no, its because the engines are aimed opposite thrust. I wanted them to hold the rover down on the ground, but now I'm using them in space to go somewhere and there is no anti maneuver node to aim at with the auto pilot. 

Nuts I am going.

 

[Cpt Kerbalkrunch]

2 hours ago, Chik Sneadlov said:

New prob. New ship and modified lander. I've run out of conventional fuel and all I have left is those nuclear decay things to produce electricity for my Xenon powered ion engines. I have lots of them. Anyhow, I mounted the lander on top of the rocket with the rocket blasts facing down, but for some reason when I set up a maneuver node, I'm burning in exactly the opposite direction that I wanted to hit with my target. There is no thing to aim for with the autopilot that is the anti maneuver. 

Its probably something to do with rotating the lander too many times in one of the directions. Its confused the computer. Or wait no, its because the engines are aimed opposite thrust. I wanted them to hold the rover down on the ground, but now I'm using them in space to go somewhere and there is no anti maneuver node to aim at with the auto pilot. 

Nuts I am going.

 

When you want to use multiple points of control on a vessel (ie: one section is built upside-down or sideways), you just need to specify where you want to control it from at a given time. You then right-click the standard, "upside-up" command pod or probecore and hit "control from here" while flying (much like what @Zhetaan suggested above for your rover; which is an absolute necessity). This will ensure your rocket behaves normally while flying. You then switch the control point when you release your rover or lander. And be careful when you change focus off your ship. When you switch back to it, specify which control-point you want to use again. It can sometimes switch back to a different one while off-focus; which you probably won't realize until you start burning and see that your going the wrong way again. It can get a bit frustrating at first, but you'll get used to these things and they won't harm your mission anymore.

And one last thing about your rover: all excellent advice above. I would just say (in case you don't already) to always make sure you have a rovemate probecore (right-side up, preferably) horizontally placed somewhere on your rover. Then place the docking port or Klaw on the front or back (or both) as Zhetaan said. I find that, as long as I do this, I don't have to worry about disabling any reaction wheels. Males controlling it a bit less tedious. You'll get the hang of it.

Edited December 18, 2017 by Cpt Kerbalkrunch

[Zhetaan]

5 hours ago, Chik Sneadlov said:

There is no thing to aim for with the autopilot that is the anti maneuver.

Nuts I am going.

I know two relatively easy ways around this that do not require a mission restart.  I'm going to assume that your lander doesn't have a correctly-oriented control point (the solution to that is simply to select it as the control point, as @Cpt Kerbalkrunch said) and that you are stuck with your engine orientation.

First, you would need to remember the position of your manoeuvre marker on the navball and figure out the position that is the exact opposite of that; this isn't so difficult if you orient yourself to the marker and then use yaw to spin about exactly 180 degrees (you have a heading readout on the navball, so getting that exact isn't too difficult).  By changing only yaw, you don't need to correct your pitch or roll.

Second, instead of trying to find or make an anti-manoeuvre node, you can just plan an anti-manoeuvre.  What I mean by this is to take your planned burn (this would work best with uncomplicated purely-prograde or purely-retrograde burns) and note the required delta-V (this is the number above and to the right of the navball when you set up a burn), then cancel that burn and set up one that is the opposite of that but for the same amount of delta-V.  For example, let's say you want to break Minmus orbit and return to Kerbin.  That would usually be a prograde burn from Minmus for some mid-100's value of dV--let's say you set up the burn and it costs exactly 200 dV to get a good Kerbin return.  Now grab the retrograde handle and pull it back until the dV readout goes to zero and builds up again to 200 dV.  Set the autopilot to node hold and execute your burn.  You may need to switch from node hold to stability assist before the burn; I do not know whether such a node is stable.  The plan in map view will look as though you plan to drop straight into Minmus and the required dV for the burn will climb to 400 (the correct cut-off will always be double the needed dV), but since your engines are facing the wrong way, you actually break orbit for that good Kerbin return.

I'll grant you that neither of these help very much with a landing; for that, you're either going to need to try again or else see whether you can fly-by-luck.  Some can--I remember a YouTube video of a Tylo lander that sputtered out of fuel at about ten metres above the surface completely by accident.  Minmus is a lot easier because the weak gravity gives you time to arrest your fall, flip your lander, and contact the ground gently enough that you don't break anything important.  But you'll need to do some fairly fancy piloting to pull it off.

Edited December 18, 2017 by Zhetaan

[Chik Sneadlov]

Which way do you mount the centerline of the stabilizer on a rover? I've put it in the center with the centerline of the stabilizer vertical and in line with the rocket, but that seems wrong. It probably should be near the COM of the rover and in line with the direction you want to go.  On the moon it would help you keep the wheels on the same plane as the surface, right?