RoGeorgeWhile was trying to see how much the RPM can be reduced while still keeping some decent torque, Lady Serendipity started to troll the experiment with a strange but funny phenomena:
The motor have a tendency to stand-up and to self-balance, apparently in a non-stable position. This is not a case of gyroscopic stabilization, the RPM is too low (motor at 2V). Also, if the RPM is increased, the self-balance doesn't happen any more.
I noticed this strange self-centering phenomena before, it was happening to other objects too (i.e. when a short flexible rubber hose is put instead of a drill bit, or the washing machine that suddenly tries to demolish the house at 1000 RPM, but works smooth at 1600). Always given them various explanations, but now I think the explanations were all wrong.
- The self-centering was noticed only in a certain RPM range, to fast or too slow, and it won't happen.
- The equilibrium happens at a certain rate of load increase, or RPM increase, then keep them constant
- If the self-centering equilibrium is lost, even if the RPM is kept constant, the self-centering doesn't happen until a new ramp-load
- All the time there is some flexible articulation involved, that allows a lot of free giggling between the load and the motor
Will add 'investigate self-centering' to the bucket list, not enough time for it now.
Grrr..., I can hardly keep myself not to go for the self-centering right now!
Discussions
Become a Hackaday.io Member
Create an account to leave a comment. Already have an account? Log In.
Hey RoGeorge :-)
What you are looking at is a parametric phenomena. All oscillating and rotating systems have at least one harmonic frequency where they will shake themselves apart, fall over, creep across the floor or even stand up. It's the exact same one that allows an opera singer to shatter a glass with her voice (apocryphally lol).
There exists a complex relationship between the forces exerted by the wires supplying the device and the direction of travel, the grip on the surface and the weight and centre of gravity, which at one point will all roughly cancel or go wildly out of control - the process is called Hysteresis.
In your experiment the ball comes to a point where it falls into a natural orbit, a band of frequencies where forces roughly cancel that is echoed in our solar system as well as the arrangement of electrons orbiting a group of protons and neutrons.
This banding is responsible for our periodic table; without it the elements would fuse at random and produce a slurry rather than distinct phased matter configurations. I cannot tell you how the mechanism works; the mathematics are beyond the means I have to study them, but I can tell you it is part of the natural order, and probably worth studying for what you are doing because it is repeatable as a result.
Orbital mechanics is a study in itself ;-)
Are you sure? yes | no
Thank you for the starting points, I'll search for them after the contest.
Are you sure? yes | no