Disinfectant Robot

This project was awarded by the Nepal Academy of Science and Technology as part of its COVID-19 Combat and Innovation Program. The initiative aimed to address the rapid spread of the COVID-19 disease by devising a strategy to minimize human exposure through the deployment of robots for disinfection procedures within hospital settings in Kathmandu. The study also anticipated that this approach would prove instrumental in reducing the likelihood of secondary infections among COVID-19 patients, thanks to the effective removal of bacterial and fungal pathogens responsible for nosocomial infections. The anticipated outcome of the project was to safeguard valuable lives from exposure and decrease the mortality and morbidity rates associated with the disease. The project received approval in mid-July 2020 and was successfully concluded by the end of October 2020. 

Design

The updated version features a robust full-metallic body for enhanced strength and agility, replacing the previous transparent design. With a reduced overall size and increased ground clearance due to the new 15 cm diameter wheels, the internal space is now more compact and thoughtfully arranged for electronic component security. A dedicated compartment ensures the safety of the motherboard and power source. Version 2.0 also introduces a new mopping system at the rear. The frames, though smaller, efficiently house all major components. Enclosed in a fully covered metal body, indicator LEDs maintain a polished appearance. The upgraded robot stands at a mockup height of 60 cm from the ground, boasting a distinctive curvilinear design in dark green. 

Parts

The majority of electronic components remain consistent with the initial version in the new system. The electronic circuit board, along with its major components, was directly transferred to version 2.0. Minor adjustments were made to the circuit to accommodate the newly added mopping feature. All electronic elements and the power supply are now enclosed in a separate compartment easily accessible by opening the metal cover. A proximity sensor was removed from the rear to make room for the sweeping mop.

The primary modifications pertain to the physical structure, involving alterations or replacements of various mechanical parts and components. Notably, the disinfectant tank has been upgraded to a fully metallic construction, replacing the plastic jerrycan, with a reduced capacity of 3 liters from 5 liters. Larger tires have replaced smaller ones, and a robust support frame has been designed to hold the spray arms, serving as both structural reinforcement and an aesthetic enhancement. A high-torque 100 RPM 12-volt DC motor is a key addition to the second version, driving the sweeping mop after disinfectant application. The two lipo batteries have been substituted with a 12V lead battery, and the charging system has been adjusted accordingly. Furthermore, a new nozzle with variable dispersion capability is incorporated, housed within a fully metallic arm.

Mechanism

The new version retains the differential wheel drive mechanism. A significant addition is the 7-inch mop, powered by a high-torque DC motor, necessitating minor adjustments to the electronic circuitry. The arm design, now 35 cm in total height, features a base-shifted joint, replacing the initial two-half system. Arm movement maintains its 2 degrees of freedom, with an expanded range of 360 degrees horizontally, up from 180 degrees in the previous version. 

Notable features of Version 2.0 robot

• Full metal body

• Compact body structure

• High ground clearance

• Metal arm with base drive movement

• Metal tank for disinfectant liquid

• Mop addition at rear

• Improved nozzle performance

• 360 degree arm movement