# Open-loop vibrational control of an inverted pendulum

Explanation 8 resources
Last Edited: 07/10/2022

This journey explains how inverted pendulums can be balanced with an open-loop vibrational controller.

All of these resources come from the excellent Twitter thread (referenced below) that @ahmedallibhoy posted on Feb. 1, 2022. The phase plane image in the thumbnail was generated by code written by Ahmed as well (also referenced below).

This Twitter thread is really all you need to click on.  Everything below this is just a listing of the resources that are called out throughout the thread.

Intermediate
Social Media
Application

This Twitter thread by @ahmedallibhoy walks through an explanation of controlling an inverted pendulum with an open-loop vibrational controller.

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This is the video that inspired the thread. Check out a vibrational controller in action!

## Suspending a pendulum in its inverted position using a jig saw (Take 1, norm...

1 min
Beginner
Video
Demonstration

When a pendulum is attached to a jig saw, strange things can happen! :)

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For more detailed information on the mathematics behind what's happening in the above YouTube video and Twitter thread, check out this paper ...

## Averaging and Vibrational Control of Mechanical Systems

Intermediate
Peer Reviewed Paper
Theory

Abstract. This paper investigates averaging theory and oscillatory control for a large class of mechanical systems. A link between averaging and controllability theory is presented by...

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... and this paper.

## Vibrational control of nonlinear systems: Vibrational controllability and tr...

Intermediate
Peer Reviewed Paper
Theory

In the first part of this work, the criteria for the existence of stabilizing parametric oscillations have been derived. In the present paper, the problem of choosing the stabilizing...

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If you want to generate the gifs and images in the thread yourself, Ahmed has posted all of the code on GitHub.

These next two books were recommended by Ahmed as great sources for those who are really interested in reading more about this theory.

## Nonlinear Oscillations, Dynamical Systems, and Bifurcations of Vector Fields...

Beginner
Book
Theory

From the reviews: "This book is concerned with the application of methods from dynamical systems and bifurcation theories to the study of nonlinear oscillations. Chapter 1 provides a review...

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## Averaging Methods in Nonlinear Dynamical Systems

Intermediate
Book
Theory

Perturbation theory and in particular normal form theory has shown strong growth during the last decades. So it is not surprising that the authors have presented an extensive revision of the...

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This video was recommended by Mario Figueiredo in the comments of the thread. It's a well-produced video explaining some research from UCI School of Engineering that shows vibrational control in insect flight.

## Vibrational Control in Insect Flight

7 min
Intermediate
Video
Application

Abstract: It is generally accepted among biology and engineering communities that insects are unstable at hover. However, existing approaches that rely on direct averaging do not fully...

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