Physical Lung Simulator

1. Physical Lung Simulator F. Zezulka, Drauschke A., Bures Z., Krejci I., Balcar J., Prochazka M. Polytechnics of Jihlava Department of Electrotechnic and Informatics University of Applied Sciences FH – TechnikumWienn zezulka@feec.vutbr.cz

2. Content • Introduction • Device overview • i-Lung simulator • Electronics of the simulator • Sensor network • Control and sensor parts • Conclusion

3. Introduction Operation program AT - CZ OP Researchand DevelopmentforInnovations ProjectElbik– M 00176 Dep. of Electrotechnics and Informatics College of Polytechnics Jihlava and University of Applied Sciences, Technikum Wien

4. Introduction • current exposure to aerosols nanoparticles and fine dust increasecases of pulmonary diseases • nowdays still little information about the distribution of inhaled particles in the lung • information is important for pharmaceutical industry providing inhalable diagnostics and therapeutics • the aim of the presented lung simulator i-Lung enables experiments to enhanced requested information

5. i-Lung module • i-Lung is an active mechanical lung simulator • offers the use of different lung equivalents • primed porcine lung or latex bags • i-Lung uses a non destructive aerosol measurement system for measuring the size and amount of in- and exhaled particles • a first step into the direction of replacing laboratory animals for inhalation test • the research corresponds orders of the EU REACH regulations

6. Device overview • the i-Lung 2.0 is an active physical lung simulator • different pathological breathing situations can be simulated • and inhaled and exhaled particles can be produced and detected • physical realization and electronics design will be presented • the next figure shows the whole i-Lung 2.0 system

7. Schematicdiagram of the i-Lung 2.0 setup

8. Principle of the i-Lung 2.0 • System consists from • chamber – plexiglass • negative pressure is created within the chamber • lung equivalents can be mounted via the connective flange • the chamber is connected to a bellows system and a vacuum pump • the bellow system is an operating system which create the negative pressure in the chamber • the vacuum pump compensates some leakages in the bellow in order to achieve a more realistic anatomical and physiological breathing situation

9. Principle of the i-Lung 2.0 • the bellows movement of compression and extension is in direct correlation to the ball-screw in the middle of the bellow • motor rotates the ball-screw which has the effect that the bottom of the bellows is moved downward or upward • pressure changes within the chamber cause an inflation and deflation of the used lung equivalent • speed of the motor evokes the air flow “F” to or from lung equivalent • the air flow is compared continuously with the desired course of respiratory curve “F = f (t)” (next figure)

10. Respiratory curve

11. Control and measurement • control of the flow and/or pressure • control of temperature • measuring of humidity in the chamber and in the ambient • UV sensor provides auxiliary function measurements during sterilization by UV radiation.

12. Electronics • consist of single board computer (SBC03), display and keyboard • SBC03 contains a ARM9 (Linux OS) which is connected to a Cortex M3 (real time processor) via SPI • Cortex M3 sends signals and commands to the Driver of the motor and the power switch of the vacuum pump • Cortex M3 collect all data from the sensor network and the limit switches of the bellows • switches the M3 again send signals to driver and vacuum pump as well as data to the ARM9 for further processing • data then can be displayed numerical or as graphs on the PC and display

13. Sensor network 1/2 • respiratory cycle, ie, inhale and exhale for a period T = 2 s, ie, the frequency of 0.5 Hz • for sampling during the reference breathing curve has been selected 100 samples per cycle, ie, Ts is the sampling frequency of 50 Hz • the sampling frequency allows implement appropriate modulation signals that occur in pathological breath, a frequency less than 25 Hz • the reference respiratory curves are stored in the data memory of control comp

14. Sensor network 2/2 • from memory the data will be released with the mentioned sampling frequency, which will also be sampling frequency of the regulation loop • auxiliary variables (temperature, humidity, pressure, etc.) are characterized as slow • these data do not have to be captured at each sample frequency (sampling rate 1 sec) • time-division multiplexing of samples to reduce the capacitive load for line. For this purpose RS485 communication protocol was used with baud rate of 115 kbps.

15. List of sensors The sensor network currently consists of sensors: • Box Flow meter • Box Temperature • Box Differential Pressure • Box Humidity • Ambient Temperature • Ambient Pressure • Ambient Humidity All of them are connected to the Cortex M3 using the RS485 bus and power with either 12V or 5V.

16. Control part • Control part consists of main control board processor based on Cortex M3 – for operation • Or by CompactRIO NI system – for experimentalpurposes • Reduced sensor system • direct connection of sensors to the microcontroller control system or CompactRIO • one – way air flow sensors • because of their big non – linearity in opposite flow directions • two flow sensors are connected in serial point – to point connection • option with pressure sensors in investigation

17. Conclusion 1/2 • physical realization of a Lung model • the i-Lung 2.0 is an active physical lung simulator • the goal of investigation is in research of influence of aerosols on human body (lung) by breathing • particular attention by such an investigation is in replacinglaboratory animals for inhalation test as ordered by the EU REACH regulation • authors describe electro - mechanical model of the i-Lung 2.0 system • the electrical and particularly sensor, communication and microcontroller based control sub – systems

18. Conclusion 2/2 • the i-Lung 2.0 system enhances the previous models of artificial lung • a bellows system and a vacuum pump • bellowshas more appropriate relation weight – power • next investigations – compensation of leakages in the bellows by more sophisticated control • implementation of an optimal tracking control of the flow • control of flow by control of the differential pressure

19. Acknowledgements Operational Program Researchand Development forInnovations Project Elbik– M 00176 Dep. of Electrotechnics and Informatics College of Polytechnics Jihlava and University of Applied Sciences, Technikum Wien

20. References • Forjan M, Stiglbrunner K, Zbynek B, Drauschke A: Overview of the "i-Lung" as developing active lung simulator including respiration aerosol measurement. Pittsburgh: ACTA Press, 2011 • European Commission: REACH. European Commis-sion, 2012. Available at: http://ec.europa.eu/environment/chemicals/reach/reach_intro.htm • Ari A, Hess D, Myers T, Rau J: A Guide to Aerosol Delivery Devices for Respiratory Therapists. 2nd Ed. American Association for Respiratory Care, 2009 • Forjan M, Stiglbrunner K, Steiner T, Zbynek B, Drauschke A: Sensor System Development for the Novel Spontaneous Active Breathing Lung Simulator, i-Lung. Vienna: UAS Technikum Wien, 2011

21. Thank you for your attention Any questions?