Can an Inverted Pendulum Stand on End Indefinitely?

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In summary, the conversation is about calculating the movement of an inverted pendulum standing straight up with a small initial angle and a weight of 1.9kg and a radius of 0.42m. The equations of motion for an inverted pendulum are similar to those of a hanging pendulum, but the inverted pendulum tends to fall away from its equilibrium point. Theoretical calculations suggest that, without external factors such as vibrations or air motion, the inverted pendulum could stand indefinitely, but the uncertainty principle would cause it to fall after a few seconds.
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rotkiv4
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Hi!

I'm working on a thing that could be simplified as a pendulum standing straight up. I've found some formulas on how a pendel moves when it's hanging on "the lower 180°" but can't figure out if it's possible to apply them on the other upper half.

So what I'm trying to calculate is how many degrees a straight up standing (small initial angle/not standing stable) is turning/falling in 0.1 seconds. My measurement says it has m=1.9kg and r= 0.42m.

Reguards // Viktor
 
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  • #2
rotkiv4 said:
Hi!
I've found some formulas on how a pendel moves when it's hanging on "the lower 180°" but can't figure out if it's possible to apply them on the other upper half.

I guess it depends on which equations you're referring to. The equations of motion for an inverted pendulum are very similar to the equations of motion of a hanging pendulum, with the biggest difference being that the inverted pendulum tends to fall away from its equilibrium point, while the hanging pendulum falls towards it.

It's not difficult to derive these equations. Have you tried yet?

-Kerry
 
  • #3
Theoretically, without vibrations or air motion, there should be an inverted pendulum position that would allow it to stand on end indefinitely. However, if you apply the uncertainty principle, specifically delta-x, delta-p <= h-bar to the pendulum mass, this uncertainty will require the pendulum to fall in a few seconds. I recall a similar problem in Quantum Mechanics class of a pencil standing on end.
 

FAQ: Can an Inverted Pendulum Stand on End Indefinitely?

What is a straight up standing pendulum?

A straight up standing pendulum is a type of pendulum that is suspended vertically from a fixed point. It consists of a weight or bob at the bottom and a string or rod at the top. The bob is free to swing back and forth, creating a regular oscillation.

How does a straight up standing pendulum work?

The motion of a straight up standing pendulum is governed by the laws of physics, specifically the principles of gravity and inertia. As the bob swings back and forth, it experiences forces that cause it to accelerate and change direction. This results in a constant back and forth motion until it eventually comes to a stop due to friction and air resistance.

What factors affect the motion of a straight up standing pendulum?

The motion of a straight up standing pendulum is affected by several factors, including the length of the string or rod, the weight of the bob, and the angle at which it is released. The height at which it is suspended, air resistance, and friction also play a role in its motion.

What is the period of a straight up standing pendulum?

The period of a straight up standing pendulum is the time it takes for one complete back and forth swing. It is dependent on the length of the string or rod and the acceleration due to gravity. The period can be calculated using the equation T=2π√(L/g), where T is the period, L is the length, and g is the acceleration due to gravity.

What are the applications of a straight up standing pendulum?

Straight up standing pendulums have several practical applications, including timekeeping devices, seismometers for measuring earthquakes, and accelerometers for measuring acceleration. They are also commonly used in educational settings to demonstrate principles of physics and to study harmonic motion.

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