Historically, robots have been designed to operate on the outsideof objects or to work in an environment where there are very fewconstraints. But there are situations when working on the insideis essential. Examples include inspection of nuclear facilitiesor industrial equipment or a submarine where the hazards or costsprohibit disassembly.
That's where snake-arm robots come in.Many dangerous, time-consuming and otherwise impossible tasks canbe simplified by these machines, which can reach the heart of aparticular application without touching or damaging anycomponents on the way.
A snake robot doesn't have wheels orlegs, but moves by flexing its joints.
By using its own body asscaffolding, the robot acquires an extensive motion range,including the vertical direction.
Since a snake robot is composedof a number of similar co-operating cells, where each cell is anindependent unit, it becomes easy to manufacture, inexpensive andeasy to maintain.
In principle, a snake robot can climb bywriggling up a pole, and climb vertical steps by using its ownbody as scaffolding.
Applications could include clearing mines orfinding survivors after natural disasters, always assuming theywould also withstand the shock of seeing an artificial snakecoming to rescue them! Snake robots are examples ofhyper-redundant robots, or robots with a large number of degreesof freedom.
Interestingly, such robots borrow inspiration fromanimals, in this case from jellyfish, worms and colonies ofone-cell animals such as amoebas and volvox.
From a roboticspoint of view, these life forms have many interesting features.They consist of many small parts, which are not complicated, butwhich combined have advanced properties.
The snake is basically arobotic arm, comprising a number of individual segments, with adrive unit controlling one or more of them.
Taken to itsultimate, each individual segment can be controlled independentlyand has its own specific motors.
A typical five-segment machinewould be powered by 15 motors.
The company is using Maxon MotorA-max or EC models with planetary gearheads and encoders.
For areally flexible 20-segment machine, as many as 60 motors would beused, all computer controlled and working in synchronised motion.One of the prime target applications is servicing jet engines.The snake arm robot travels down the air path to inspectinaccessible components, removing the need for manual access ordismantling.
Importantly, the snake arm robot can enter theengine and travel through the fan blades while components arestill hit, reducing downtime and improving turnaround.
Otherapplications planned include operating TV cameras, searchingvessels and vehicles for drugs, working in boilers or ovens anddrilling underground.
In the medical world, the snake arm robotmay be used in keyhole surgery - again, the key advantage overcurrent procedures is that the whole device may be controlled,not just the tip.
These snakes need to be long and flexible -ideally like a piece of steerable string.
OCRobotics isconsidering arms as long as 15m with a diameter of only 80mm.These are seriously flexible devices which need support fromtheir environment, but they would be ideal for exploring acollapsed building or exploring the drains.
In effect thesedevices take the advantages of endoscopes and combine them withthe motion control of a robot creating a device that is bothflexible and can be controlled to follow a path.
Another key areafor snake arm robots is for shorter devices that need to carry asignificant payload - lets say an arm with a reach of 3m and apayload of 20kg.
Such an arm is ideal when the workingenvironment is not benign or static.
Oil and gas exploration isnow being conducted at depths of more than 2000m.
At this deptheverything is conducted remotely so examining a wellhead orremoving it at the end of its life requires some very capableremote technology.
Snake-arm robots also create the opportunityto explore old and new worlds in a different way.
So recent pressabout space exploration being conducted by robots is relevant -it's great to have a set of wheels or legs to manoeuvre overrough terrain but arms are very useful for going beyond a justlooking mode and getting your hands dirty - picking up bits ofrock to take a closer look or to stick them in your pocket.Clearly there is a whole load of interest in unmanned militaryoperations.
But whilst there is significant investment inunmanned aircraft and subs, the challenges with traversing adesert or forest or beach are considerable.
Solutions to thesechallenges are available although the next range of vehicles islikely to be aimed at what may appear more straightforwardapplications - for instance guarding military or industrialfacilities.
One thing that is difficult to get across is just howstraightforward it is to control these things.
Basically, theoperator sees where the snake-arm is going using a tip-mountedcamera and changes direction using a joystick - like flying anaircraft.
The clever bit is the software that keeps track ofwhere the rest of the device is and makes sure that it keeps asclose as required to the path the camera has traced.
This meansit can avoid obstacles and makes it possible to interactivelyexplore a structure - going forwards then backing up creating atree of paths.
Of course if the path is known offline then motioncontrol becomes much more straightforward.
OCRobotics is based inBristol and has close links with the aerospace industry and withlocal universities.
Formed five years ago, the company hasrecently won two Smart Award from the DTI.
It launched the snakearm technology in January of this year.
The company presented apaper at a prestigious international workshop in Toulouse thisOctober on the issue of robots in human environments.
The aim ofthe workshop was to gather the world's leading researcherstogether to discuss applications ranging from surgery todelivering the internal post.
In this environment, OCRobotics isslightly out of place because our focus is commercial notacademic - but OCRobotics will be demonstrating a reliablehardware platform that could be used by researchers to take thesubject further.
If robots are to find their way into our homesthey will certainly need a map and a way of getting around.
Theywill also need to be able to get out of the way.
One of the keyrequirements for a robot interacting with people will be that,when they collide, the robot moves first - but doesn't spillthe coffee in the process.
Snake-arm robots offer the right sortof capability to achieve this - you can push the middle of thedevice out of the way whilst leaving the coffee cup in the sameplace.
We also have plans to put a skin on our arms so that theycan detect and react to contact, heat or chemicals.
