rover problems

[hyperbolicj]

So I'm designing and testing a modular base and why testing if the pieces can connect properly on kerbin I had a problem.

The rover I'm using to ferry components around needs to raise itself via landing legs dock and the lower itself and move it around.

And it can do that. But occasionally I encounter a problem where after docking with the component and lowering my legs, taking

the breaks off. I simply can not move. Wheel motor is on, electricity is topped off, breaks are off, and landing legs up, but the

vehicle simply won't move. This is despite the fact that all the component pieces are mere 2-4t in weight. If it does somehow

snap out of it the rover lurches forward dramatically. Does anyone know the cause of this?

Edited December 22, 2014 by hyperbolicj

[SpacedCowboy]

Aside from the wheels, is there anything else touching the ground? Need some pics.

[capi3101]

There are a couple of things that come to mind. Let me start with an "is it plugged in" type of question - when you want to use your rover again, are you selecting the option to "Undock" first?

[hyperbolicj]

So here's my rover just after docking to a fuel tank component

And here it is after lowering the landing legs

And I think I just solved the problem with not moving. It seems that the break indicator at the top center turns off when I dock despite not turning the break off. So I just have to toggle on and off.

Still have a problem with the vehicle lurching forward. I suppose that's because of the high center of mass and low horizontal spread of the vehicle.

[SpacedCowboy]

The lurching problem is caused by the magnetism in the docking ports... I think, try turning off any and all gyroscopes and redirecting "control from here's". Could be wrong, (cause I'm not all that "Kerb Tech" smart) Just trying to help.

[hyperbolicj]

Well that could be it. But think about it. If you draw an imaginary line from the center of mass to the contact point of the wheel. That's the axis that the vehicle has to rotate on to tip right. If like me you have a 4 wheeled symmetrical design then it would tip in the four cardinal directions on the average of two of those axis. The more vertical those are the easier it should be to tip them. Thus The wider more spread out and low to the ground design would prevent tipping of the vehicle. As to why it lurches I think it's because the acceleration that the wheels give is a particular amount and unless I'm missing something I don't think I can throttle them. So unlike in a car where you gently up the velocity you can't seem to do the same in KSP.