I have a conceptual design that I've been evaluating which can be summarized as a simple pendulum extended to 3D (i.e. swing not limited to x-z plane). If I want to actually build the conceptual design, is it possible to have a pivot point that does not permit rotation about the pendulum leg axis, but does allow for it to swing "freely" in 3D space?
An easier way to probably ask is, if the pendulum is hanging statically, can I constraint the motion such there is no rotation about the leg-axis (statically coherent with z-axis) and later, dynamically, allow for it to swing "freely" in 3D space?.
I should emphasis, I'm looking for a "product" idea that permits such motion. I thought a universal joint may work, but I think that in order to swing "freely" the joint must be able to rotate about the z-axis.
In the end, the more and more I think about it, I'm wondering if it's theoretically possible? Does this give rise the the "elastic pendulum" idea, where a spring must be involved?