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Advanced Process Control for Atmospheric Pressure Plasmas

The work in this repository is done in the Chemical and Biomolecular Engineering Deparment at University of Californa, Berkeley in Graves Lab and Mesbah Lab

This repository is being regularly updated - 06/2018

Atmospheric Pressure Plasma Jet (APPJ) devices exhibit highly variable behavior in response to changes in their environment. Small changes in, for example jet-tip-to-substrate sepration distane can cause drastic changes in the APPJ behavior. Using feedback control, we can mitigate some of this variability allowing for reliable, reproducible and effective operation of APPJs. Below, you can see how feedback control can help regulate substrate temperautre while the seperation distance changes (6x sped up).

  • Left: No Control
  • Middle: Voltage Controls Temperature V=>T
  • Right: Flow Controls Temperature q=>T

Helium plasma jet

The maximum temperature measured at the surface for each case clearly demonstrates the need for and benefit of feedback control

Helium plasma jet

For practial applications, the APPJ should also be translated over the substrate as often the APPJ sources have an effect area (~few mm^2) much smaller than practical targets (several cm^2). We achieve this using a moving stage controlled by stepper motors akin to conventional 3D printers. This allows us to freely and precisely move the APPJ in 3D.

Watch the plasma translating over a surface!

Helium plasma jet

This repository contains code used for implementing classical (proportional-integral-derivative) and advanced (optimization-based) feedback control on a kHz-exctited atmospheric pressure plasma jet in helium

Hardware

The APPJ Control project makes use of open-soruce and DIY hardware where possible. With the exception of the high voltage amplifier, all components used, including the microcontrollers, single board computer, circuitry etc. are open source and comperatively cheap. Deatiled information about the used hardware can be funed under the /Hardware directory, including circuit diagrams and datasheets.

Firmware

The Arduino firmware allows exchanging commands with the Arduino via serial monitor. The latest version (as of 14/6/18) is version 14, available under /Firmware. The firmware is configured to manage two gas flow rates, 3D position, applied voltage and frequency. Default measurements include RMS voltage, RMS current, total emission intensity and ambient temperature.

Software

Detailed information about the software is under /Software. Bulk of the software is written in Python and can be easily modified for different applications. There is a client-server architecture in place based on TCP/IP protocol. This allwos information exchange with the data aquisiton software and allows for complicated calculations to be done on external computers, on the cloud etc.

Related Academic Publications

This repository has been forked and modified from Plasma Analysis and Control by Brandon Curtis