Copacetic

(This is my second Science Week Post)

Well this was an easy one for me as I have mentioned it in the past. Landmine Detection, or more specifically a tool to detect the absence of landmines.  Absence is important because while the efforts of the miltary are devoted to finding a safe route through mine fields, the civilian population must establish that all their fields, paths, villages and workplaces are free from mines.

This device would have to be,

• Low cost
• Easy to manfacture locally (at all the locations where landmines exist)
• Capable of detecting and destroy plastic mines amongst others

The ultimate goal is of course a device that makes mining (especially anti-personnel mines) obsolete by making them completely ineffective.

I read in Time magazine (27-Nov-2006, Dublin Edition) about silly string (you know the spray can stuff that squirts out like string). It is in demand as a trip wire detection device  in Iraq. Apparently the marines squirt it into a doorway and it hangs on tripwires without triggering the attached mine.

These Self healing Minefields are just plain freaky. How the hell are you ever expected to clear them? Even if you wanted to keep a map, any intrusion would totally stuff up the map.

James Trevelyan writes cogently on why Robots are not an appropriate solution for landmine clearance. Readers will be aware of my previous post on this topic where I proposed a robotic solution. Well James well and truely sank my boat with his excellent analysis of why robots won’t work, then in the last paragraph he gives me renewed hope,

Sandia Laboratories and some other groups are working on highly sensitive chemical sniffers which could develop into devices to be carried by robots into unknown areas to see whether there are residual traces of explosive vapour. Dogs can also be used in this context – the MEDDS system used in South Africa for instance – see the US Army Website.

Here are some other relevant links from James’s website,

• General overview on Demining research
• Common myths about demining
• An excellent paper on robotics in general with some significant detail on a robot that could successfully shear sheep

Landmine clearance is an idea I’ve given some thought to, but I can’t execute on it right now. So I thought I’d park it here and update it as I find out more about the problem space. As far as my limited knowledge goes the problem is defined by the following parameters,

• The one common ingredient in all landmines is explosive
• One landmine costs about $3 dollars to lay and between $300 and $1000 to defuse
• Landmines (particularily anti-personnel mines) are often scattered indiscriminately over a wide area (often by air)
• There are over 110 million landmines extant today (mostly in the third world)
• Clearing landmines is an extremely dangerous occupation

Any solution to the problem must have the following characteristics (to my mind):

• Be of the same order of magnitude in cost as the cost of laying (lets say $5)
• Not involve any human interaction
• Detect all kinds of explosive devices (purpose built landmines and home made devices)

Ergo, build a self-contained, self-sustaining, insect-like robot. The robot will have,

• A chemical sniffer for detecting explosives
• Solar power so it can operate without recharging
• A wireless network capability so it can communicate with its peers
• GPS so it can pinpoint the location of landmines to its peers (and a master)
• A simple search algorithm so it can operate in isolation
• A more complicated search algorithm so it can collaborate with its peers if they are detected
• A non-lethal tamperproof mechanism to discourage theft, tampering

A network of these could be scattered by helicopter over affected areas and scour the area searching for mines. Once detected the mines need to be disarmed (I don’t know how we might do this at the moment, but detection is a great start). The GPS would allow each robot to indicate its search route and the master could be used to collect and upload search data to a central location. This map could be overlaid over a standard topo map to indicate danger areas, unscanned areas or areas left to be cleared. Each robot would attempt to link to all the others to form a mesh network. This network could then be used by the group to establish new areas to check or to scan existing areas twice etc.

The hard problem is not the individual components, its fitting them all into a resilient, cheap, easy to manufacture package that can be deployed with a minimum of expertise and used directly by locals with a minimum of training.

Potential Problems:

• Still don’t have a good plan for disabling them
• Getting everything into a small enough package is a challenge
• How do we prevent theft damage of the devices before they do their job
• What if you were to attach a mine to these devices and use them as the weapons they were intended to protect against
• Can a chemical sniffer be made that can detect all the most common kinds of explosives
• Is GPS accurate enough to allow safe detection (the mesh network may be able to triangulate itself, though)

My robotics links are on delicious.