Mysterious bouncing rover!?

[Arugela]

I have this rover:

http://www./download/3o9icrc925aac0v/The_Orion_Rover.craft

It has this problem of hitting mysterious spots in the ground(or I assume) and bouncing in the air like it hit a massive boulder and got air. This tends to break the rover or it's wheels making kerbaless driving less than ideal. On top of the endless glitches I seemed to run into with kerbals on the vessel for repairs... Does anyone know what causes this or how to get around it. I've moded the COM more to the middle by shoving the Monopropelliant tanks down but it didn't make any difference from what I remember.

This thing is also extremely sensitive to wheels breaking. Is it overweight?

Hotkeys:

1: Toggle torque (off by default) This is for getting flipped upright if upside down.

Here is the vehicle in the air after doing something similar to if you hit a rock and popped a wheely. Except you go upside down in the air and tumble:

I'm not refering to the vehicles tendency for the nose to go in the air when accelerating or anything similar. This is something that always happens when going over flat terrain and usually at high speeds to cover ground to get somewhere. It's like it hits a bump in the ground and flies up and crashes and sometimes blows up. It makes it basically unusuable for long distance travel as you cannot safely maintain high speed for long distances. It's also completely random. It sometimes happens at low speeds and sometimes breaks wheels or just flips over a little.

Edited October 26, 2015 by Arugela

[G'th]

Depends on where you're driving it. Most places rovers going too fast are going to cause some bad times.

The thing you have to realize is that most rovers are absurdly fast even though the metric speedometer doesn't really clue you in on that. You might think 10m/s is slow going but in reality you're going over 30mph at least (or something like that, think I might have the actual conversion off by, a lot Point still stands though). And those wheels in particular can get you going up to 15-20m/s.

When it comes to rovers, take it slow. Very slow. Otherwise as soon as you hit a bump in the ground you'll go flying especially on anything that doesn't have at least 1G on the surface. And even then.

Getting your COM lower will help, but what'll help even more is to pack even more mass into the rover so it hugs the ground as much as possible. If you want a fast rover, make it a fat one too. But even so, go too fast and you'll still have a bad time.

[Arugela]

My main problem is I wanted it to travel long distances and be able to fly with mono(or other RCS) on low gravity planets. It's designed to go with a mothership and I need it to be reusable. Hence the electricity packed in for the wheels and the other resources being near infinite for the vehicles use. I actually just took off a bunch of struts that I put on to see if it helped. This lightened the vehicle even more. And it was acting worse afterthis. I haven't tested how affective the RCS is yet or determined the range.

I'm guessing this stuff is normal for rovers then. any idea how heavy it should be? I could always put on verners or other propultion and more fuel to weight it down.

On a side note: Any idea how to get a sphere of 3 small RCS wheels to go in the direction it would if driving. Mine for some reason always goes in other direction while the reaction wheels are active. it's good for flipping over when needed but I can't control it to use like RCS in space potentially.

Edit: The rover even just mysteriously blew up without even hitting a bump... This game is cursed. Whatever I do I cannot get my rover to the beach!

Edited October 25, 2015 by Arugela

[G'th]

Indeed it is normal. Just got to learn to take it slow. You really only want to let loose the speed when you know you have a solid flat surface to travel over. Definitely don't travel under warp if you've been doing so.

As for how heavy, however heavy whatever you use to launch it wherever you plan on using it lets it be. I have a rover I made for Duna that masses around 20t depending on what I have on its trailer, and most of its mass is concentrated towards the ground, and its over 5m wide. It drives really well even at high speed in low gravity, but even so if you let the speed get out of hand or if you end up making one bad turn (or indeed, hit the random bump) it'll still flip.

As for the RCS placement question, that sounds possible but I'm not sure what you're referring to by "RCS wheels" and where you want them pointed.

[Arugela]

by RCS wheels I mean torque/reaction wheels. I have to turn on the reaction wheels torque then hit "d" to flip forward as opposed to sideways like if you were driving.

[Snark]

A couple of things:

Bear in mind that rover wheel suspensions have a fair amount of flex built into them. The view you get in the VAB is the ideal zero-gravity case where there's no sag at all. In general, it's a good idea when designing rovers to give them a fair amount of ground clearance. That shielded docking port that you have slung underneath looks like it's ground-scrapingly low. If I had to guess what's causing your weird behavior, it would be that the docking port is clipping into the ground and giving the physics engine indigestion. Suggest either getting rid of it, or else moving the wheels lower to get some ground clearance.

Regarding your broken-wheel woes: the wheels you're using are very fragile ones. As soon as you can upgrade your tech, try using the ruggedized ones available at the 550-science tier. They go a bit faster and are much more damage-resistant.

by RCS wheels I mean torque/reaction wheels. I have to turn on the reaction wheels torque then hit "d" to flip forward as opposed to sideways like if you were driving.

Call them reaction wheels, not "RCS" wheels, if you don't want to confuse KSPers.

"RCS" specifically means the multidirectional thruster system used for docking and the like, fueled by monopropellant (or LFO in the case of Vernor engines).

...Later...

Okay, I just loaded your craft, and see some other reasons for confusion here.

For one thing, you're making heavy use of part clipping, with pieces inside other pieces. Be aware that KSP can be finicky about clipping-- you can do it, but you're more likely to run into physics glitches if you do. With as much clipping as you're using, it's a miracle that the rover doesn't spontaneously blow up just sitting on the launch pad. If you can find a way to redesign your rover to not use so much clipping, you'll likely have a saner experience.

Also, you're using the RoveMate as your probe core. That means that when you're sitting on the surface, your navball will be very confusing: your rover is "looking" straight up at the sky, which will make it hard to steer. Suggest adding a forward-facing probe core (like an OKTO2) that you can then designate as "Control From Here" when you're landed, so that your navball will be sane (the horizon will show what a forward-facing driver sees, with sky above and land below).

This is no doubt contributing to your reaction-wheel problems. When you tell the reaction wheel "yaw left" by hitting the A key, that's based on an upward looking viewpoint, which means it doesn't steer the rover towards the left, it will try to roll it over sideways. Total confusion.

Added to this is the fact that (rather confusingly) KSP maps rover steering controls to the same WASD by default that are used for controlling torque rotation. I solved this by remapping the rover steering controls from WASD to the numpad keys 8456, so that when I'm steering my rover I'm not also causing confusing torque commands.

By the way, I noticed that in your rover you've got a set of three torque wheels intersecting each other at right angles. I know you didn't do this for cosmetic reasons, since they're clipped inside the rover and invisible. Therefore, I assume you're trying to accomplish some sort of control this way. Be advised that you don't need to do this. A single reaction wheel works for torque on all axes. You don't need to make a "sphere" out of them, just stack three of them normally if one isn't enough.

So, the summary of how to fix your rover:

1. Stop clipping all those parts inside each other. Yes, this will mean a total redesign of your rover.

2. Give it a forward-facing probe core that you can "Control From Here" when you're landed.

3. Upgrade to rugged wheels if you can.

4. Give it some ground clearance so that you don't have any parts scraping the ground. You only want the wheels touching the ground.

I'd also recommend giving it a much longer wheelbase (distance from front to rear wheels). Your wheelbase is really short, that will make it easy to flip over forwards when braking.

Edited October 26, 2015 by Snark

[Arugela]

Here is my updated version:

http://www./download/y0cyhuboubce8u1/The_Orion_Rover%282%29.craft

If you drive it on caplocks it is very stable. It still has some problems with blowing up if it flips to fast, but you can keep it manageble from what I can see now. I think most of the blowing up is from the parts stacking now. I will have to try to strut stuff down and see if I can control it without adding too much weight. Next step on this rover is to get it's flight characteristics how I want them with RCS.

I also found a cool acceleration bug unique to the area near the obelisk at KSC. It lets you accelerate to super speeds by hitting the breaks. Instead of stopping you fly forward really fast!

Edit: I can drive it at 4x time acceleration now. But It has a really hard time going up inclines. Is this normal for rovers?

Edited October 26, 2015 by Arugela

[Snark]

If you drive it on caplocks it is very stable. It still has some problems with blowing up if it flips to fast, but you can keep it manageble from what I can see now.

Glad it's working better for you!

By the way, a word about rovers and mass (per some discussion earlier in the thread):

any idea how heavy it should be? I could always put on verners or other propultion and more fuel to weight it down.

...There's never any reason to "weight down" a rover. Adding mass to a rover doesn't make it more stable or less prone to flipping. Adding weight makes it heavier, yes, but also increases its inertia too, which precisely mathematically cancels out the benefit from the added weight. Rovers are more stable on heavy-gravity worlds because that adds weight without adding mass.

It's also worth noting that the more kilograms of mass you have riding on each wheel, the easier it is for the wheel to break when you're rolling over terrain.

When you're designing the rover, therefore, lighter is better. Don't add mass just for the sake of adding mass. Much more important is geometry-- get the center of mass as low as you can. If it's prone to tipping forward/backward, make the wheelbase longer (i.e. bigger distance between front and rear wheels). Reaction wheels with SAS can help, too, though if you've got a lot of reaction torque on your rover, you need to learn how to steer with it in concert with your wheels, since otherwise you can end up with the reaction wheels fighting against you whenever you try to turn.

[Arugela]

If it has a hard time going up inclines is it likely overweight. The new version seems to not easily get up the hills going to the mountains behind KSC.

[Keldor]

One thing I've noticed is that there's a bug with wheel traction in physics warp. It seems to stay the same while the rest of the world moves faster, so it's like driving on ice. Thus, if you need to climb something, make sure to go to 1x time!

[Brainlord Mesomorph]

Did you use hyperedit?

Hyperedit once did a very weird things to a rover for me. I’d use that to telport into the orbit of Eeloo, and land there. And as soon as I drove any distance from the landing site, the nose of the vehicle just went up in the air.

Like the front end was on a string being pulled up, or the front wheels suddenly had antigravity, or I was the bottom of some invisible force cone. I could use RSC and SAS to push the nose down, but as soon as I stopped, SHWING! Up it went.

I blame it on file corruption caused by hyperedit.

[Arugela]

Nope I didn't use hyperedit. But I think the problem is solved sufficiently. If it flips is usually survives now. Except going fast downhill.

Latest version:

http://www./download/6qp008b96agxp0m/The_Orion_Rover%283%29.craft

Instructions are in the vehicles description in the VAB/SPH!