R06 Questions

[SamM]

<R06> states that

The ROVER WHEELS must
be used in a “normal” orientation (i.e. with the tread of the wheel in contact with the ground,
with the axis of rotation parallel to the ground and penetrating the wheel hub).

My first question is: what defines the axis of rotation? Is it only the axis that the wheel rotates about to produce motion of the robot, or does it apply to any and all rotations of the wheel.
For example, by my understanding any wheel that uses a 'steering' system, has two axes of rotation, one through the wheel hub, and one through whatever axes the wheel turns around to change its orientation.
Similarly, many suspension systems, allow the wheel to move up or down based on slight angular rotations about a pivot point that is parallel to the wheel's rotation but passing through a point on the frame, well outside the wheel.

Second axis of rotation
|
|.......................Wheel
|..................._ /
o------------I o I
....................--

o----____........._
..............-----I o I
.......................--
Secondly: Would a suspension system like this, either on springs, or controlled, be legal, assuming that its motion does not result in a significant change in robot height that would affect bumper, and trailer height calculations?