Rover Control

[MPDerksen]

I got my first rover onto Minmus tonight. A couple things did not go as planned, however.  2 of my wheels were blown???  And in the process of driving it out from under my lander, I tipped the lander over, so now it is on it's side.  When I right-click on the rover body, I see I have some reaction wheel options.  But I have NO idea what I'm doing.  I can get the entire rover to do flips, but barely get it to just drive forward.  It just wants to do somersaults.....  I select the wheels and there are options for the motors, direction, etc.  I'm really not sure what I should do, since it didn't do this on Kerbin during the launch pad test.

I'm really not that concerned about the tipped lander.  I need to send a rescue craft anyway since the plan was to bring HALF of the deployable science on the first trip with the rover, then follow up with an engineer to place the solar.  But if there is a clever way to get it upright and back to orbit, then it makes my rescue a bit easier since Val can just head up to the mobile lab in orbit.

And finally, Bob collected some Green Sandstone from the Minmus Flats.  He has to return it to Kerbin.  I don't see it in his inventory slot, and nothing is noted when I right-click on him at all to indicate he is carrying it.  How do I make sure it doesn't get left behind in the rover when he goes home?

Advice?

Edited August 27, 2019 by MPDerksen

[vossiewulf]

Wheels on the left side of the rover should have motors set to normal. Wheels on the right side should have motors reversed.

Wheels forward of the center of mass should have normal steering. Wheels behind the center of mass should have steering reversed (or steering locked).

There are also low speed and high speed steering ranges, you can set the low speed limits fairly broad to give you good steering at low speed, but you should also limit the high speed steering to a very small range, to prevent overcontrol/turning over on high speed turns. I will set primary driving wheels to a high speed range of no more than .2.

Minmus isn't much fun for rovers. Rovers need some gravity to work reasonably well, and Minmus don't got it. Rovers are very hard to control and even harder to stop. The best use of a rover on Minmus is to set up something small like a Packrat with a bunch of science experiments with a rover autopilot and a Bon Voyage controller, and have BV drive it from biome to biome (or anomaly) and let it deal with the frustration of very low-g driving.

[AHHans]

1 hour ago, MPDerksen said:

And finally, Bob collected some Green Sandstone from the Minmus Flats.  He has to return it to Kerbin.  I don't see it in his inventory slot, and nothing is noted when I right-click on him at all to indicate he is carrying it.  How do I make sure it doesn't get left behind in the rover when he goes home?

These kinds of stones transform into a science experiment when they are picked up. So when you look at the science reports the Bob has on him, or in the capsule where he deposited them, then you should see a "Green Sandstone Analysis" in there. AFAIK that's the part that you need to bring back to fulfill the contract.

[bewing]

11 hours ago, MPDerksen said:

I can get the entire rover to do flips, but barely get it to just drive forward.  It just wants to do somersaults....

This is often caused by the probe core not pointing in the correct direction on the craft. It needs to point forwards. If this is the problem it's easiest to see by looking at your navball when your rover is sitting on its wheels. The navball should be half blue and half brown, and should be pointing at the correct compass heading as the nose of your rover.

If the probe core is pointing in the wrong direction, then wheel commands will be interpreted wrong.

Another possibility is that you have a lot of reaction wheel torque available, and you have not separated the "drive a rover" commands from the reaction wheel "rotate vessel" commands. By default, both are assigned to the WASD keys. You really don't want that. It's very inconvenient to have your rover try to spin and flip every time you tell it to just go forward. I moved my rover driving commands to the Home/End/Delete/PgDwn keys.

[Zhetaan]

12 hours ago, MPDerksen said:

I can get the entire rover to do flips, but barely get it to just drive forward.  It just wants to do somersaults.....

 

56 minutes ago, bewing said:

Another possibility is that you have a lot of reaction wheel torque available, and you have not separated the "drive a rover" commands from the reaction wheel "rotate vessel" commands. By default, both are assigned to the WASD keys. You really don't want that. It's very inconvenient to have your rover try to spin and flip every time you tell it to just go forward. I moved my rover driving commands to the Home/End/Delete/PgDwn keys.

Additionally, you can shut off the reaction wheels, though that leaves you unable to right the rover when you do flip.  As @bewing does, I prefer to disconnect the wheel controls from WASD, but I assign them to the number pad:  8 is forward, 4 is left, 6 is right, 2 is reverse, and 5 is brake.  I've seen 0 used as the brake, too.

[MPDerksen]

 

Tipped over lander, and rover with 2 blown wheels!  The wheels were blown in transit to Minmus, NOT on landing.  No clue how that could have happened, since it was in a fairing.  Plus, any advice on getting that lander upright?  The mission plan is to send Val up to the station, and Bob will stay behind until Lander #2 comes with the rest of the deployable science and an engineer.  Then everyone goes up, and Bob stays in the orbiting mobile lab.

Here are the options for my lander can.  When I click on the Reaction Wheels, I can cycle through options like "SAS only" and "Pilot", but I don't understand what these mean.  I'm also really not sure what settings to use on the wheels themselves.  From the picture above, my closest to success is driving it backwards, which is to the right.  I already harvested the science on this biome and want to head to the next.

[bewing]

1 hour ago, MPDerksen said:

The wheels were blown in transit to Minmus, NOT on landing.  No clue how that could have happened, since it was in a fairing.

When you blow the shell on a fairing, if the wheels are too close to the shell, they get destroyed.

1 hour ago, MPDerksen said:

Here are the options for my lander can.  When I click on the Reaction Wheels, I can cycle through options like "SAS only" and "Pilot", but I don't understand what these mean.

You understand that when you click between different SAS modes, that SAS uses the reaction wheels to turn your craft around? You understand that when you hit WASD, that also uses the reaction wheels to rotate your craft? Clicking that button disables either SAS or WASD from using the reaction wheels.

On minmus, sometimes just turning SAS to "Radial Out" can cause a vessel to stand up all by itself. Sometimes, doing that and then having a kerbal push themselves under your vessel and then jump will give your craft enough of a boost for it to stand up. Or, extending the landing legs, then retracting them, then immediately setting SAS to Radial Out works. If you don't have Radial Out as an SAS mode, then sometimes you have to do it yourself with WASD. You probably want your lander to rock upwards onto its nose, and then fall back down to start it rotating in the correct direction.

 

 

[MPDerksen]

3 hours ago, bewing said:

When you blow the shell on a fairing, if the wheels are too close to the shell, they get destroyed.

You understand that when you click between different SAS modes, that SAS uses the reaction wheels to turn your craft around? You understand that when you hit WASD, that also uses the reaction wheels to rotate your craft? Clicking that button disables either SAS or WASD from using the reaction wheels.

On minmus, sometimes just turning SAS to "Radial Out" can cause a vessel to stand up all by itself. Sometimes, doing that and then having a kerbal push themselves under your vessel and then jump will give your craft enough of a boost for it to stand up. Or, extending the landing legs, then retracting them, then immediately setting SAS to Radial Out works. If you don't have Radial Out as an SAS mode, then sometimes you have to do it yourself with WASD. You probably want your lander to rock upwards onto its nose, and then fall back down to start it rotating in the correct direction.

 

 

Ahhh, so I maybe need a slightly taller spacer between the bottom of the rover and the fairing part.  Thanks for that, it's not something I would have easily discovered on my own.

Seems like righting the lander will require some trial and error.  Val is only a level 1 yet (prograde and retrograde SAS thus far).  I love the idea of getting her onboard, then having Bob use his RCS under the lander to give it a bump. 

note that picture 2 of the Mk2 lander can is the ROVER, not the LANDER.  That is where I'm trying to understand my options for controlling the Rover and getting rid of the reaction wheels.  I don't believe my Lander has either RCS or Rxn Wheels, since I can only move it by playing with gentle throttle and the legs.

[VoidSquid]

On 8/28/2019 at 6:47 AM, MPDerksen said:

When you blow the shell on a fairing, if the wheels are too close to the shell, they get destroyed.

I also painfully have learned that additionally increasing the fairing ejection force helps a lot, still counterintuitive to me, but it works.

As for orientation, flipping, etc., my little "Unirover" here

has two probe cores, as you can see, one on top of the tank just below one of the solar panels, the other on its rear. The first one is for landing the rover, the other one for driving around.