MECHANICAL VENTILATOR DESIGN FOR COVID-19 PATIENT WITH RESISTIVE BELT SENSOR

: A ventilator is a machine that gives mechanical ventilation by moving breathable air into and out of the lungs, to convey breaths to a patient who is genuinely unfit to inhale, or breathing deficiently. In this paper, a resistive chest belt sensor based mechanical air ventilator is designed to give the COVID-19 patient the desired air volume to inhale based on the expansion of the patient chest for needing more air. The resistive belt sensor senses the expansion of the patient chest and controls a solenoid valve that attached with oxygen compressor. The ventilator performance has been tested with MATLAB/Simulink tool with the aid of a Proportional Integral Derivative (PID) Controller and a promising result has been obtained.

given to the solenoid valve increases so that more air volume will get out from the solenoid valve. The solenoid valve is attached to oxygen compressor and the amount of air volume is controlled by the solenoid valve. The block diagram of the ventilator system is shown in Figure 1 below.

 Resistive Sensor Chest Belt
The resistive chest belt is simply a belt with a resistor attached on it and when the patient air breath increases the belt expands and the resistor length will be changed and also the resistance of the belt increases. where G(s) is the transfer function between the input voltage and output air volume.  Tidal Volume (TV) It is the measure of air that can be breathed in or breathed out during one respiratory cycle]. This portrays the elements of the respiratory focuses, respiratory muscles and the mechanics of the lung and chest divider. The typical grown-up esteem is 10% of indispensable limit (VC), around 300-500ml (6-8 ml/kg); however, can increment up to half of VC on breathing incapacity happen. The relationship between the patient inhale air volume and the belt length is assumed to be linear. The chest diameter for adult person with age b/n 30-35 and height of 1.55 meter is 0.8 meter.
For normal berating the relationship becomes

PROPOSED CONTROLLER DESIGN
A PID controller is an instrument utilized in mechanical control applications to direct temperature, stream, pressing factor, speed and other cycle factors. PID (corresponding vital subordinate) regulators utilize a control circle input instrument to control measure factors and are the most precise and stable regulator. PID control is a grounded method of driving a framework towards an objective position or level. It's a basically universal as a method for controlling temperature and discovers application in heap synthetic and logical cycles just as robotization. PID control utilizes shut circle control input to keep the genuine yield from a cycle as near the objective or setpoint yield as could be expected.

RESULT AND DISCUSSION  System Parameters
Copper has a resistivity of 0.0171 Ohm · mm²/m and is, therefore, one of the best conductors for electric current and mentioned above the belt length is 0.8m and let the belt area becomes 40 mm2. Therefore, the normal air volume resistance becomes The Simulink block diagram of the mechanical ventilator is shown in Figure 3 below. Here in this system, a PID controller with auto tuner system, a solenoid valve transfer function, a sudden patient air volume, air volume to change in belt length, length to resistance converter, inhale air volume scope and output resistance scope blocks are shown below.

 Simulation of the Actual Belt
Resistance to Reference Resistance with Patient Normal Breathing The simulation result of the patient normal breathing for a given reference resistance output actual resistance and air volume inhale are shown in Figure 4 and Figure 5 respectively. The simulation result shows that the reference and actual resistances are the same and there is no error resistance signal and the solenoid valve will continue to give the patient an amount of air volume of 500 ml of oxygen volume.

 Simulation of the Actual Belt
Resistance to Reference Resistance with Patient Sudden Air Volume Inhale The simulation result of the patient sudden air volume inhale of 300 ml for a given reference resistance output actual resistance and air volume inhale are shown in Figure 6 and   The simulation result shows that the actual resistances increases because the increase in chest diameter or length of the belt and there is an error resistance signal which adjusted the solenoid valve to give the patient a sufficient oxygen volume and the patient will continue to breath with an air volume of 800 ml of oxygen.

CONCLUSION
In this paper, a resistive belt sensor based mechanical air ventilator has been designed for COVID-19 patients successfully. The resistive belt sensor attached to the patient chest to sense the resistance of the belt while the patient breathes. PID controller have been implemented to the mechanical ventilator in order to test the response of the system. The system response test has been done with the aid of MATLAB/Simulink for a patient with normal breathing and sudden breathing change. The simulation results shows that the system has a better response and for the future work the system performance may be improved if another controller implemented.