Its realistic models for the large and small screen have won it BAFTA awards, and its projects have included the critically acclaimed BBC series Walking with Dinosaurs. The Buckingham firm Crawley Creatures has accumulated more than 28 years’ experience producing animatronics and prosthetics for feature films and television.
However, in the past decade, the company has moved into a more unlikely field – defence robotics. Its projects in this area involve building animatronic mannequins for global defence firms for the testing of chemical, biological, radiological
and nuclear defence (CBRN) suits and equipment to be used by
infantry soldiers.
So, how did the company make the move into a sector that is miles away from the glitz of the film industry? It was a bit of a strange jump, agrees Jez Gibson-Harris, chief executive of Crawley Creatures. But the defence industry was seeking to test its CBRN suits and equipment in ever more realistic conditions, and what caught its attention was the company’s ability to create lifelike, fluidly moving robotics.
The company’s first foray into the defence sector came about when a research scientist developing CBRN protective equipment at the Defence Science and Technology Laboratory (DSTL) – an executive agency of the Ministry of Defence (MoD) in Porton Down, Wiltshire – watched an episode of Walking with Dinosaurs.
“He spotted our company’s name on the credits and got in contact with us,” says Gibson-Harris. “They asked us to make a robotic head form to test respirators by simulating some movements that they would previously get squaddies to do.” The requirement included getting the robot to make various head and facial movements, and recite passages of text, while wearing the respirator in a small chamber filled with a harmless, vaporised saline.
The Crawley Creatures team developed the robotic head form, dubbed the Porton Head, by drawing upon their years of animatronics expertise. “It was fairly simple, and was made to move using radio-controlled servos – the kind of technology we would use in the film and TV industry,” says Gibson-Harris.
To make ‘skin’ for the head, they opted for materials normally used to create realistic-looking prosthetics for characters on TV and film. “We would normally use soft polymers such as silicon, foam latex and rubbers,” says Gibson-Harris. “We chose to create the skin from a soft elastomer, so that when they put a respirator on, it would create a similar sort of compression and seal around it, just like human skin.”
Later contracts with DSTL saw the team at Crawley Creatures develop sweating head forms, complete with cameras in the eyes, that were used to test and develop helmets for the Eurofighter Typhoon aircraft, with sufficient air flow to ensure the visor did not mist.
The firm’s innovative work with DSTL resulted in more defence projects from around the world starting to roll in, and led to the creation of a subsidiary company, i-bodi, which specialises in the development of computer-controlled test platforms for evaluating respirators and chemical biological (CB) protective clothing.
One of the focuses in this field for Gibson-Harris and his team has been the development of lifelike robotic mannequins to test CBRN protective clothing for clients including the Canadian, French and Australian governments. However, the past two years have seen i-bodi working with DSTL again to develop its most advanced animatronic mannequin to date. Using state-of-the-art technology, Porton Man can mimic a soldier’s movements. It can walk, sit, march, run, kneel and even lift its arms up as if to sight a weapon. The new mannequin replaces an original Porton Man that has been in use at DSTL, Porton Down, since the late 1990s.
Before the use of robotic mannequins, the military would develop protective clothing using subsystem testing, taking swatches of fabric and measuring how much agent penetrates the fabric, says Colin Willis, group principal of chemical biological radiological defence at DSTL. “This previous method shows whether the fabric is working, and allows comparisons between different fabrics. What it doesn’t do is tell you how that fabric will perform when it is turned into a suit, or system,” he says. So DSTL had little data to tell whether the fabric would be able to withstand the stresses and strains of movement, and what effect incident winds would have on its performance.
The lack of data prompted the government to pioneer system testing for CB suits and led to the creation of the first Porton Man animated mannequin. “It could simulate a marching motion, which was adjustable, and from the tests run on the original mannequin we were able to make dramatic improvements over existing clothing,” says Willis. “It was the first-generation Porton Man that was responsible for bringing our current Mark 4A CBRN suit into service.”
However, after a decade of use, the mannequin was starting to look tired. “It was built by a company that makes crash test dummies, and it was heavy and mechanical,” he says. The chemical biological radiological defence team wanted to create a new Porton Man that would take advantage of the latest engineering and materials. They managed to secure £1.1 million of internal funding, and put the proposal to develop a new mannequin out to tender. The contract was eventually awarded to i-bodi.
Dr Jaime Cummins, of DSTL’s chemical and biological physical protection group, says the brief given to i-bodi for the new Porton Man was simple: remove the limitations of the old mannequin. “The old mannequin had a very basic marching motion and the head couldn’t move,” he says. “It faced only one direction during the exposure period and incident winds. The mannequin was also heavy, weighing 75kg, and it required specialist lifting equipment to remove the mannequin from the frame to dress it properly.”
Mike Franklin, chief design engineer at i-bodi, says that as well as making the new mannequin lighter and giving it a greater range of motion and more realistic movements, the firm was also asked to make the mannequin look “more like a human being”. This effect was achieved using anthropometric data supplied by the MoD, with the new Porton Man created to be the same height and weight as the 50th percentile of 2,500 servicemen from all branches of the military.
Once this data was received, the i-bodi team used several processes to design Porton Man, once again drawing upon techniques and software regularly used in the film industry. “We used zBrush, a software program which is generally used in the film and gaming industry for character creation,” says Gibson-Harris. “It works fine, but unfortunately it has no measurements within it, so we had to create boxes that everything went into, and draw within these space frames. We then used another software program called GeoMagic and surfaced it before we could take it into our Inventor 3D CAD, to create all the joints and mechanical components to go within it.”
Considering which materials to use for the Porton Man was a slightly trickier task. “The UK is the only country that uses a real agent to test its CB protective clothing,” says Gibson-Harris. “These tend to be agents and stimulants such as methyl salicylate, which is used in deep-heating liniments such as Bengay.” This sticky substance, he says, can be vaporised and pumped into the test chamber, and is later washed down using bleach or peroxide. Working with this type of test left the firm with a limited palette of materials to choose from, he says.
It ended up opting for 316 stainless steel for the framework, as well as a lot of deep hard anodised aluminium components for lightness. For plastics, the firm chose polytetrafluoroethylene and polyvinylidene fluoride, that would survive the treatments and not absorb chemicals. Finally, to protect exposed cables, it over-heat-shrank them with a protective Viton fluoroelastomer covering.
Weight reduction was achieved by the use of light, but highly durable, carbon composite to create the mannequin’s body, drawing upon the expertise of useful neighbouring firms. “We used a couple of companies locally that do composites for Formula 1, that also five-axis machined our patterns for us,” says Gibson-Harris. The result was a significantly lighter mannequin, with Porton Man weighing in at a svelte 14kg.
The mannequin’s movement is based on pairs of drives and AC servomotors, which create a realistic range of motions. Creating bespoke hydraulic systems and actuators would have been ideal, but budget restrictions meant sticking with off-the-shelf parts wherever possible, says Franklin. In some cases, this led to some unusual creative solutions. “We used a right-angled drive, hollow-shaft gearbox, which I used to pass through the second axis from the first axis, to drive sections of the actuators. I don’t think gearbox supplier Parker ever thought its product would be used in that
way,” he says.
To ensure the Porton Man movements are as fluid and friction-free as possible, i-bodi opted to use igus iglidur Z and X bearings on all rotating shafts. Usefully, the bearings require no maintenance or lubrication and are resistant to the kinds of conditions the mannequin will experience in the DSTL test chamber, says Franklin.
The engineering team also had to ensure the mannequin could rotate in the chamber – a specification that DSTL requested so it could subject CBRN suits to different wind directions. To achieve this rotation, the mannequin is mounted on a wirelessly controlled turntable that rotates by ±180º. It also locks into place on the floor, with simple drop-down feet.
“Building a turntable isn’t too difficult,” says Franklin. “But building a turntable with 18 sets of cabling going through it, that has to do ±180º, as well as having to be decontaminable – that was probably one of the biggest challenges.”
This challenge was overcome by using an igus ‘reverse bending radius’ energy chain solution for the mounting platform for the mannequin. The system guides and protects cables as the mannequin rotates, ensuring there is no danger to the connections during the test.
However, Gibson-Harris and Franklin agree, the biggest challenge of all was getting the mannequin to fit through the narrow entrance to the test chamber, which involves transporting it manually up and down ramps and through small airlocks. It must then be set up by staff wearing often bulky protective gear. These considerations had a big impact on the design of the mannequin, says Gibson-Harris. The i-bodi team had to ensure that it was compact and easily transportable as well as quick to assemble, with the set-up time now reduced to just 15 minutes.
“The height restrictions also meant that the head had to be detachable,” says Franklin. “It is wireless and battery-powered. It can nod, tilt and rotate, but it is a totally sealed unit on a bayonet that snaps into the top of the neck.”
Porton Man is also fitted with around 280 stainless steel ports that house passive sensors: small stainless steel tubes that contain a powder called Tenax (a porous polymer resin). “If any chemical gets in, the Tenax absorbs that chemical,” says Gibson-Harris. “After the test, it will be put into a gas chromatograph and analysed – it will tell you how much material was absorbed and where the chemical came in.” However, to ensure even more accurate data, DSTL is hoping to install realtime sensors into Porton Man by next year.
DSTL is now in possession of the new, improved Porton Man, and will begin tests in earnest next year. The aim is to begin developing the next generation of considerably lighter clothing for use in hotter climates, moving on from the current Mark 4a suits originally designed for use in the Cold War, says Willis. “If it is going to be lighter, we want to make sure that it really does protect, so it is important to get these additional ranges of movements into the clothing, and an indication of how the clothing behaves in real time.” Further adaption to the existing mannequin may include upgrading it to heat or sweat, but it will depend on what technologies become available for these purposes.
Other exciting developments under way in CBRN suit testing include untethered robotic mannequins that Willis calls the “ultimate aspiration”. However, this technology is decades away from being developed in the UK, he says. For now, it seems, Porton Man’s job is safe