Robot arm aims to reach the unreachable

A novel snake arm robot developed by OC Robotics uses as many as 60 miniature motors to provide freedom of motion.

A snake arm robot - it sounds like science fiction.

But it is very much fact - and is proving invaluable in situations where no person ever wants to go.

Designed by OC Robotics of Bristol, the 'snake' is basically a robotic arm, comprising a number of individual segments, with a drive unit controlling one or more of them.

It is the fact that each individual segment can be controlled independently and has its own specific motors that makes the robot unique.

Many dangerous, time consuming and otherwise impossible tasks will be made simple by this machine which can reach the heart of a particular application without touching or damaging any components on the way.

For example, one of its prime tasks is expected to be the servicing of jet engines - the snake arm robot travelling down the air path to inspect inaccessible components - removing the need for manual access or dismantling and saving time and money.

Importantly, the snake arm robot can enter the engine and travel through the fan blades while components are still hot, reducing downtime and improving turn-around.

Other applications planned include operating TV cameras, searching vessels and vehicles for drugs, working in boilers or ovens or drilling underground.

In the medical world, the snake arm robot may be used in keyhole surgery - again the key advantage over current procedures being that the whole device can be controlled - not just the tip.

It will even be able to assist with one of the most dangerous applications of all - nuclear decommissioning.

Consisting of as many as 20 segments, the robotic arm is powered by ultra-compact Maxon motors.

A typical five segment machine would be powered by 15 Maxon A-max motors or EC with planetary gearheads and encoders.

For the really flexible 20 segment machines, as many as 60 motors would be used - all computer controlled and working in synchronised motion.

In situations such as nuclear decommissioning, working at the heart of fires, in avalanche or earthquake conditions, or underwater, the drive unit (including motors) can be housed in a shielded container many metres from the flexible arm.

While 'reaching the unreachable' may be the prime purpose of this extraordinary machine, what do you do when you get there? Apart from a 'tip vision' camera, other tools may include laser welders, ultrasound scanners and water jet cutting.

The snake arm robot can carry a payload of 10g right up to 100kg.

Based in Bristol, OC Robotics has close links with the aerospace industry and with local universities.

Formed five years ago and recent winner of two 'Smart' awards from the Department of Trade and Industry, the company launched its snake arm technology in January 2002.

"We've always used Maxon motors", said a company spokesman.

"We've never had one go wrong.

Although we have been offered what may appear cheap options by other manufacturers, we'd much rather stick with the reliability and quality that Maxon offer.

We are building an excellent relationship with them".

"I specified Maxon in the design because they work with me through the whole design and production engineering process.

For example, I particularly like the free Maxon product selector program.

I was able to try out different products and evaluate them.

With this program, I could chart across a whole range of speeds and currents and use the interactive facility to try things in situ.

The end result is much greater peace of mind".

"We're quite used to our motors going where people cannot", said Keith Ellenden of Maxon Motor UK.

"Our motors can be found in some extraordinary places - remote-controlled bomb disposal equipment, satellites in space, micro pumps in the human heart, probes surveying the rocks of Mars and inside furnaces where temperatures can reach 1700 degrees.

The snake arm robot is one more example of a Maxon motor going into a really demanding application".

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