Kerbal Space Program

I’m seeing similar behavior on OSX, with Breaking Ground (and Making History).

My attempts have involved two vessels on the ground. One is a ‘stationary’ landed vessel with docking ports. The other is a ‘rover’, which is mobile using wheels. I’m using (stock) robotic parts to facilitate docking.

On the ‘rover’, I have a CanadArm style assembly, which consists of Servo, Hinge, Piston, Hinge. At the end of the last hinge is a docking port, which I’m trying to dock with the stationary, ‘landed’ vessel.

What happens: When the ‘rover’s’ robotic arm and docking port attach to the docking port of the other vessel, the two ports appear to try to line up with one port ‘flipped’ 180 deg. This ends up violently flipping the lighter vessel. Usually one vessel ends up clipped inside the other vessel. On low G bodies (Minmus) the process usually has enough energy to send one or both vessels flying and tumbling.

Adding screenshots.

I've tried reducing servo, hinge, and piston motor strength to the lowest settings.

Did some more testing, using simpler vehicles.

In attempt 1, I attached Dock Port Jr.'s to hinges on the ends of the vessel. The hinges were initially aligned for docking. This test was successful, no docking issues.

In attempt 2, I attached the same Dock Port Jr.'s to the same hinges, but this time the hinges were not initially aligned for docking. I needed to rotate the hinge(s) 90 deg. to dock. This resulted in the following bizarre results:

- The vessels lurched violently during docking.
- The docking ports were 'joined', however their alignment was not correct, roughly 90 deg. off.
- After undocking, one Dock Port Jr.'s attachment to it's hinge is now 90 deg. off, appears to have permanently changed the geometry of the pair.

One guess is that after docking, the docking port tries to orient itself how it was when the vessel was launched.

More screenshots.