Powering robots for medical sterilisation – and the fight against COVID-19…

Author : Eric Lind | Vice President of Commercial Operations & Business Development | Ultralife

01 August 2021

Hospital ward
Hospital ward

Effective decontamination & sterilisation of hospital wards & bathrooms is essential in reducing the risk of cross infection. This is particularly important during the current COVID-19 pandemic – especially when we consider that there are just 9 critical care beds per 100,000 people in the UK.

This full version of this article was originally featured in the August 2021 issue of EPDT magazine [read the digital issue]. And sign up to receive your own copy each month.

Here, Eric Lind, Vice President of Commercial Operations & Business Development at battery & power expert, Ultralife discusses the vital role robotics can play in sterilisation – and what to consider when specifying a power supply...

Public Health England, as well as other organisations spanning the UK & Ireland, recently published joint guidance for COVID-19 infection prevention and control in healthcare settings. In particular, patient isolation rooms must be terminally cleaned following each patient’s transfer or discharge from the hospital, including removing all detachable objects in the room and cleaning everything from the ceiling (lighting and air duct surfaces) down to the floor. It is a time consuming and, in light of the current pandemic, dangerous task.

A study from Duke Medicine, the medical school of Duke University in North Carolina, USA and one of the world’s foremost patient care & biomedical research institutions, showed that enhanced cleaning strategies, such as using portable ultraviolet (UV) machines, can kill drug and cleaning-resistant organisms, and demonstrated that these techniques can make meaningful differences in patient outcomes. These UV light technologies have been used for decades in water and air purification, but combining them with autonomous robots in healthcare settings is a recent — but much needed — development.

The robots emit UV-C light, a type of ultraviolet light that is not found on earth, unlike UV-A and UV-B, which are well-known to cause sunburn. Therefore, viruses and bacteria are not immune to UV-C. When this type of ultraviolet light shines onto germs, it attacks their DNA, so they cannot infect another person.

UV-C mobile robot
UV-C mobile robot

To emit UV-C light, a typical sterilisation robot incorporates a disinfection lamp with an accumulated intensity of 250 to 280 uv/cm2 and a coverage radius of six to eight metres. The lamp is connected to either a mains powered mobile cart on wheels, which staff have to move from room to room, or an autonomous mobile robot (AMR).

AMRs are similar to AGVs (automated guided vehicles) in a warehouse, autonomously navigating around buildings for most of the day, every day. They are therefore reliant on batteries as their main source of power. The power demands on the battery are particularly high due to the disinfection lamp, which may need to be recharged every few hours.

Therefore, AMR batteries are usually recharged in the same way that AGV batteries are. The robots are self-aware of how much power they have left and, when the battery is running low, they automatically navigate to a charging station to recharge.

Usually in AMRs, the battery is used as a ballast to keep the centre of balance low, but the weight must not be enough to inhibit mobility. This means that the strength and weight of the battery, as well as long run time and fast charge time, are key requirements in this application. Traditionally, sealed lead acid (SLA) batteries have been used in applications with similar requirements.


Nowadays, however, original equipment manufacturers (OEMs) tend to favour replacing SLA batteries with lithium iron phosphate (LiFePO4) alternatives, as these are three times lighter for the same energy...

UV-C robots play an important role in the fight against COVID-19, with studies suggesting that 99.9% of coronaviruses can be killed when exposed to far-UVC light. Batteries fulfil the equally important functions of powering the robot or transmitting data back to the user. Therefore, selecting the battery that meets the robot’s power and weight requirements is vital to ensuring smooth  and successful operation...

Read the full article in EPDT's August 2021 digital issue...

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