piflixe / ilr

iterative learning control on Arduino Due

ILR

iterative learning control on Arduino Due

This work was started for a master thesis at the Technical University of Berlin. The aim of this work is to establish a closed loop control for the excitation of mechanical test setups.

Problem description:

When performing mechanical oscillating tests on non-linear structures, it is very hard to establish a sober excitation force of only one single frequency.

"Normal" computer-controlled measuring eqipment is not able to adjust the output very fast since information is buffered and the adjustment of the real-time module is very limited.

Idea:

Usage of iterative learning control to improve the signal used to excite the mechanical non-linear structure from period to period.

The control is implemented on an ArduinoDue with high real-time standards. The Hardware is cheap and real-time behaviour can be examined and influenced. If needed, high-performance DACs or ADCs can be added

Usage

Copy all files in the ILR subfolder to your computer. Open ILR.ino with the Arduino IDE. Flash on an Arduino Due or compatible device.

The devices starts up in waiting mode and waits for commands on the serial interface. Just hitting enter on the serial will display help messages and the menu navigation. Parameters can be set and the experiment can be started / stopped / resetted.

In order to realise more complex tasks like a sweep experiment, external scripts can be used that send messages to the device on serial interface. I used simple matlab script for that. See SweepExperimentControl.m for more information.

Please note: An external electrical circuit might be needed to use the code on real measurement equipment. Please also be sure to have the right voltage levels. A IEPE compatible example can be found in the IEPE_Circuit subfolder.

Documentation

Full documentation is in my master thesis which can be found in main.pdf

ilr's Issues

Implement "proper" Serial messages to change parameters during runtime

Currently, messages over Serial are transmitted without any checks so things can get messed up.

-> Implement proper messages
-> one message per parameter setting (currently two due to meny structure)
-> implement complete and validity checks

Nsmooth changeable during runtime

ILCgain changeable during runtime

At the moment, ILCgain only influences SmoothingWeight, which is calculated in setup function. Hence it doesn't have any effect if ILCgain is changed during runtime.

Expected behaviour:
when ILCgain is changed, Smoothing Weight should be recalculated

Display current parameter values on serial interface

Stop Experiment with detachInterrupt

if statement in ISR changeindex() to stop experiment could be replaced by detachInterrupt and therefore making ISR faster