Meet the electric hospital porter

Motol University Hospital in Prague is supported by a network of autonomous vehicles that deliver vital supplies to doctors and patients. Sam Shead reports

The thought of robots in hospitals is enough to make the hairs on the back of your neck stand on end. Yet one particular hospital in the Czech Republic has just welcomed a further 10 to its work force.

Scared? Do not fear. The robots are in fact automated guided vehicles (AGVs) and will merely be used to transport surgical tools as opposed to wielding the instruments themselves.

AGVs can be programmed to open doors and use lifts
AGVs can be programmed to open doors and use lifts

AGVs are becoming increasingly popular in hospitals as a mode of transport for efficiently moving goods around.

These driverless vehicles typically move linen, refuse, medical waste, patient meals, soiled foot trays and even surgical instruments from A to B. They can be programmed to open doors and use lifts automatically, granting them access to practically any area in a building.

Motol University Hospital in Prague is the largest hospital in the Czech Republic and it’s already taking full advantage of AGV technology.

Hampshire-based E&K Automation provided the Czech hospital with a flexible AGV system in 1995 that has been significantly upgraded throughout the course of the last year.

Today, the institution’s infrastructure includes a 38-unit AGV network that transports goods within and between the different buildings, including the original children’s hospital complex and an adult hospital built some years later.

The vehicles are specifically designed to transport pre-loaded trolleys around the hospital. Mike Burke, a project manager at E&K Automation, told The Engineer: ’The AGV drives underneath the trolley and fits between the caster wheels. There are jacks built into the AGV that push upwards and lift the trolley off the floor.’

But how do the vehicles know where to go – and how do they get there?

“The wires create a magnetic field and each vehicle has an antenna onboard to detect that field”


’There’s a core system that takes in requests for containers to be moved,’ said Burke.

AGVs transport pre-loaded trolleys around the hospital
AGVs transport pre-loaded trolleys around the hospital

The requests can come from patient wards or from service areas in the hospital’s basement, such as the kitchen and the laundry area.
They are then distributed to a fleet of vehicles and the one that is best located is sent to collect the container and transport it to the desired location.

’The vehicles follow inductive wires in the floor,’ explained Burke. This technology, known as inductive guidance, involves a network of wires that carry alternating currents at different frequencies.

’The wires create a magnetic field and each vehicle has an antenna onboard to detect that field,’ said Burke.

The vehicles are programmed to detect and follow certain magnetic fields on their route in order to get them to their destination.

In 2006 the complex modernisation of the children’s hospital was instigated, which was only completed in April 2011. It included a €2.8m (£2.3m) project for E&K to supply 10 new AGVs to join the 28 existing ones and extend the AGV system to all of the children’s wards, bringing the total track length to 3,400m.

The reconstruction also involved installing 10 new lifts for the AGVs, so that they could access wings A, B and C of the children’s hospital.

Civil work involved adding extra underground corridors through which the AGVs would be able to access both the new lifts and a newly constructed operating theatre.

Motol’s AGVs transport 900 to 1,000 containers every day
Motol’s AGVs transport 900 to 1,000 containers every day

’The likelihood is that the new vehicles could run faster, but there’s no point because the old ones can’t,’ said Burke, pointing out that AGVs moving at different speeds could cause ’mayhem’ on the network.

It was also impractical to extend the AGV transport network and retain the old communication system.

’In the original system we used inductive communications, which relied on an additional wire in the floor for transmitting digital information between the vehicles and the control PC,’ said Burke. In the current system, a WLAN-based control and communication system is used to communicate with the AGVs.

Between 900 and 1,000 containers are now transported every day around the AGV network at Motol University Hospital. As you might expect, it was essential that the automated movement of goods around the hospital was not affected during the transition.

Switching between the old and new control systems was done by means of a simple changeover switch.

Each night, when batteries powering the 1995 vehicles were being recharged, the new vehicles, the control system, the lift controls and the WLAN were tested.

E&K found this to be the most difficult time during the modernisation of the project, because at 5:30 the next morning the entire system had to operate at full capacity again.

The presence of AGVs in UK hospitals is limited to one or two facilities.

Burke said that the AGVs don’t save time but do save labour, because they eliminate the need for porters. With the NHS looking to cut costs at every corner, are the porter-replacing AGVs a bargain for Britain?

Well, Burke claims they will reduce payload damage significantly because the AGVs won’t bash into things, ’whereas porters tend to do things like that’, he said.

’I have tried to get people interested in AGV networks in Britain but we don’t build hospitals over here like they do on the continent.

’The UK tends to build hospitals with large footprints and low-level hospitals; whereas on the continent they build tall hospitals with a small footprint, which means all the services can be put in the basement and things can be moved predominantly in lifts,’ added Burke.

What’s new

Copper control
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Direct order
Siemens has announced the signing of the UK’s largest contract for direct-drive wind turbines and will be supplying 17 direct-drive turbines for Eneco Wind UK, at Lochluichart wind farm in the Scottish Highlands. The 51MW project is the largest investment to date in the UK for Eneco Wind UK, a subsidiary or Eneco Wind in the Netherlands. Siemens will supply 17 SWT-3.0-101 direct-drive turbines, with a tip height of 125m, to the wind farm. Christopher Ehlers, UK managing director at Siemens Renewables, said: ’Siemens already has an extensive portfolio of onshore wind-power projects in Scotland, which play a key role in the Scottish government’s low-carbon strategy. Lochluichart is our second direct-drive contract in the UK and the largest in the UK to date. This latest order is an excellent sign of the development of the market.’ The wind farm will start being developed at the end of this year on the Lochluichart Estate, located on the higher land between Loch Glascarnoch and Lochluichart, and should be in full operation by 2014.

Super sewer
The Mersey Valley Processing Centre (MVPC) at Shell Green, Warrington, is the sewage processing centre for a huge swathe of the region, stretching from Liverpool to parts of Greater Manchester, handling and incinerating up to 87,000 tonnes of biosolid waste each year that is fed to it by the Mersey Valley Sludge Pipeline (MVSP). United Utilities, MVPC’s operator, has now completed a major upgrade to key elements of the plant, including the installation of a new and more efficient sludge processing and incineration stream. At the heart of the upgrade was the deployment of a Siemens Simatic PCS7 distributed control system (DCS), to give United Utilities real-time visibility and operational control across the plant and its sludge supply network. The adoption of the PCS7 DCS as a common control platform, in conjunction with Siemens S7-400 controller technology at key stages of the process, is expected to lead to a reduction of up to 50 per cent in operational expenditure per cubic metre of raw waste.

Design essentials
The key facts to take away from this article

  • Motol University Hospital has 38 automated guided vehicles (AGVs)
  • These transport items such as surgical tools and linen to different areas
  • Previously, the AGVs were guided by inductive wires in the floor
  • To extend the network, the control system was changed to WLAN