Rover not driving straight

[zathras]

I've made several variations of this type of rover and all of them do not drive straight, they either pull to the left or right. All the parts "snapped" into place so everything should be symmetrical and the all the wheels should be contacting the ground the same. I've tried just four wheels on this frame and it still happens. Is this normal, or something with this type of design? Thanks.

[stupid_chris]

It could be due to Kerbin's rotation, since the wheels have literally zero friction.

[Tiron]

flex in the structure, possibly. Either between the arms or...well, in my experience using symmetry with wheels doesn't work very well...because the 2nd wheel doesn't really lock on to the part. It kinda vaguely floats there, and will move around quite a bit relative to what it's locked on to...I've taken to placing wheels individually.

[Benie]

I've had this happen to me several times, even using the standard rover chassis. This was a real problem on Duna for me.

Just get an SAS module on it to hold its heading. What I did, and it works.

[Jones-250]

It could be due to Kerbin's rotation, since the wheels have literally zero friction.

That´s a first. I´ve never heard that you´d have to take note of the Coriolis effect when driving a rover. And I am quite familiar with the beforementioned effect, I´m a trained sniper for Jebs sake!

[stupid_chris]

That´s a first. I´ve never heard that you´d have to take note of the Coriolis effect when driving a rover. And I am quite familiar with the beforementioned effect, I´m a trained sniper for Jebs sake!

Technically, the Coriolis effect doesn't take place at the equator. But the rover wheels have no friction. That's why if you don't engage the parking brakes, the rover will start rolling on it's own. Kerbin is rotating under it and the lack of friction in the wheels makes him want to stay stationary, so it starts rolling. Depending on it's orientation, it could make it roll sideways.

[sauliukas]

Try connecting beams with struts, that way the rover will be more rigid. Might solve the problem.

And the other problem might be that you have not enough power for all those wheels, add some solar panels or generators. Plus put some batteries too.

[Jones-250]

Technically, the Coriolis effect doesn't take place at the equator. But the rover wheels have no friction. That's why if you don't engage the parking brakes, the rover will start rolling on it's own. Kerbin is rotating under it and the lack of friction in the wheels makes him want to stay stationary, so it starts rolling. Depending on it's orientation, it could make it roll sideways.

Yeah, apparently I´m not quite familiar enough... yet. It´s still quite a strange theory you have there, however I must admit that it is plausible.

[zathras]

Thanks for the suggestions.

- Adding SAS had no effect

- Adding a lot of struts had no effect

- Adding weight had no effect.

I noticed this only happens while accelerating, if I just let it roll, it goes straight. If I let it roll down a hill and accelerate on it's own, it goes straight. So I think that means a frame flex problem or traction.

(stress/flex points that turn red would be a cool tool to find where problems are)

Edited July 4, 2013 by zathras

[zathras]

Lack of enough power for all the wheels. I added a few more generators to the rover and now it drives straight. :|

[Tiron]

Thanks for the suggestions.

- Adding SAS had no effect

- Adding a lot of struts had no effect

- Adding weight had no effect.

I noticed this only happens while accelerating, if I just let it roll, it goes straight. If I let it roll down a hill and accelerate on it's own, it goes straight. So I think that means a frame flex problem or traction.

(stress/flex points that turn red would be a cool tool to find where problems are)

I'll note you didn't say anything about trying placing the wheels individually rather than with symmetry to avoid all the wheels on one side being able to slide around on the end of the beam

[Tiron]

Lack of enough power for all the wheels. I added a few more generators to the rover and now it drives straight. :|

*Facepalm* why didn't I think of that. Gaaaah. I knew that too. Sorry Zathras.