Inverse Tripple Pendulum

This Qt-Application simulates and animates the motion of a 3-stick pendulum.

System

The system is build up with a carret, constraint to horizontal movement. Then a chain of 3 sticks is mounted onto the carret.

The calculation of the model is done in wxMaxima.

Features

• user defined masses, lengths and inertias, springs, dampings
• user defined initial coordinates
• user can drag the carret with the mouse, and try to balance the the inverse pendulum (easier with time lapse)
• user defined damping factors of each joint and for the carret
• slow motion by changing timefactor
• the springs are fixed to the initial relative angle between 2 linked sticks.

Not implemented

• a working regulator

Usage

• set dampings to zero, and watch the chaotic movement. Is like a burning fire - you can watch it for ever without getting bored. :)
• Enable "Pull by Mouse", set Time-Factor to 10, and try to balance the pendulum. It works for about 3 seconds, then normally it is too instable for balancing any more.

Known Bugs

• memory leak (C++ has no garbage collector :) )
• numeric (hopefully numeric only) instability, when spring constants are high, and dampings are low.

TODO

• calculate and print system-energy (if it should not increase with time, without any input)
• improved numerical stable solver

Compile & Run

Tested with Qt5.9 on Linux Mint 19 (based on Ubuntu 18.04)

mkdir build
cd build
qmake ..
make
chmod +x inverse-tripple-pendulum 
./inverse-tripple-pendulum