Mechatronic Design and Active Disturbance Rejection Control of a Bag Valve-Based Mechanical Ventilator

Abstract

This paper presents the mechatronic (mechanical and control system) design of a portable mechanical ventilator to treat patients with a compromised respiratory function. The portable ventilator ensures adequate oxygenation and carbon dioxide clearance while avoiding ventilator-associated lung injury (VALI). Oxygen is delivered through the compression of a bag valve (Ambu bag) using a moving strap. Carbon dioxide is cleared through the control of a pinch valve actuated by a low-torque servo motor. The positive end expiratory pressure (PEEP) is controlled by an adjustable mechanical valve the system. An Arduino Mega microcontroller board is used in this prototype to control the respiratory variables. All mechanical components as well as sensors, actuators and control hardware are of common use in robotics and are very inexpensive. The total cost of the prototype build in this work is about $425 U.S. dollars. The design is meant to be replicated and utilized in emergency conditions that involve an overwhelming number of cases, such as COVID-19 treatment, in places with no access to commercial MV technologies. In order to account for variations in the prototype as built, the software developed for this portable MV applies an active disturbance rejection control strategy (ADRC). This control strategy is presented as a universal control structure for any mechanical ventilator able to supply air flow with controlled pressure and volume.

Optimal Active Disturbance Rejection Control for Second Order Systems

“…Thus far, Active Disturbance Rejection Control (ADRC) has found widespread applications in various fields, including the control of robotic systems [8]- [10], energy systems [11], [12], autonomous vehicles [13], the chemical industry [14]- [16], civil engineering [17], and biomedical systems [18], [19]. ADRC has demonstrated its broad value in commercial applications, such as the InstaSPIN-MOTION motor control solution developed by Texas Instruments, which incorporates ADRC for high-performance control [20].…”

Low Cost and Portable Mechanical Ventilator

“…And portability adds a plus point because making it, this much portable will also eliminate many of its transportation difficulties and hazards. And in this way, it could be easily circulated worldwide, thus, the aim of serving humanity would be well accomplished [11][12][13][14][15][16][17].…”