Last update, April 19. 1997 | Current Status of activities: completed (see the Home Page).
NOTE: This page contains some outdated material and is provided for historical reasons only (illustration of early ideas and developments). Do not use any of the suggested solutions.

Demining robots and vehicles

Introduction and warnings
Military breaching and mechanical mine clearance
Military sensor movers
Demining campaign vehicles
Humanitarian mechanical solutions
Humanitarian sensor movers
Others
Vegetation cutter
References

Introduction and warnings

A demining robot should find all mines within a given area and destroy or deactivate them. A robot performing this task completely may never exist. We have to make distinctions, and since humanitarian demining is mostly concerned about anti-personnel mines, we will not mention here specific approaches for anti-tank mines, helicopter mines, submarine mines, etc.

UXOs (Unexploded Ordnance) are abundant within most minefields, which are former battlefields. They usually have an important metal content which makes them easier to find. UXOs too have to be removed or destroyed.

When talking about demining robots, one should make a clear distinction between the following solutions:

military vehicles;
not yet existing humanitarian robots, with stringent requirements;
teleoperated police robots, for picking suspicious objects;
naive proposals or studies which solve only a small easy part of the problem.

Demining teams remove patiently all the mines within a given area with scarce funding. For 40 years now, they have been using the same proven, but slow, technique because nobody developed better solutions. A good description of the demining operations is provided by Intac (http://www.intac.com/PubService/human_rights/WEAP/LANDMINES/MINES/).

One should be aware of the following points:

Armed forces use expensive equipment only UN can buy. For instance, modified tanks which remove only 90% of the mines;
R&D on mine sensors and robots is nearly absent within universities and industry research labs, no proven commercial product is proposed besides metal detectors;
human deminers in Angola or Cambodia are cheap (US$200 to US$1000 per year) and have no life insurance.

This situation should change over the next years, if the political and scientific communities decide to invest a very small percentage of the GNP of rich nations to help the countries plagued with mines. There is a future for demining robots, but the work is difficult and a better coordination of all researchers in the world is required.

Military breaching and mechanical mine clearance

As a strategic weapon, mines are laid to deny the enemy access to some area. The enemy's objective is hence to go to this place and punch a path through the minefield with acceptable losses. This is named breaching and the speed of the operation is more important than the safety of the soldiers. Typically, a tank pushes a mechanical demining system and the troops follow; removing 80% of the mines is acceptable.

Mechanical mine clearance means either actuate the mine, or remove it for later destruction. Mine actuators imitate the target by hitting or pressing above mine operating force. The main problem is to find a method of applying the pressure that is relatively immune to the explosive effect of the mine [Blagden].

Flails beat the ground with weights at the end of chains. A number of chains are mounted on a central rotor which turns rapidly. The weights hit the mines and either break them up or cause them to detonate; they resist well to anti-personnel mines.
The Aardwark (Scotland, fax +44 464 20-985), is one of the commercial product proposed for a price of about 400'000 US dollars.
Rollers are pushed by a tank and are fairly effective except on undulated or stony grounds, or heavily vegetated areas. They rarely achieve the necessary levels of clearance needed for re-habitation. Passive heavy rollers are not efficient. It is clear they cannot press evenly on the soil.
Bofors (Sweden, fax +46 586 85-700) proposes a motorized roller carried by a teleoperated Leopard 1 battle tank chassis. The rotating roller is made of a series of blades fitted with carbide teeth that either ignite the mine or chew them into small harmless pieces (but mines which are damaged and do not explode badly pollute the soil). The roller digs 20 cm or more into the ground.

See the enlarged 80 kB figure on Bofors' Web page (http://www.bofors.se/minr.htm).

The Spitfire demining concept is proposed by Caterpillar and has been developed by BOA Sweden: the patented "rotator-tool" is covered with rotating heads adequate for rock-crushing. Since the upper soil is completely mixed, there is a good hope that all the mines are destroyed. The device is claimed to withstand impacts of up to 12 kg of TNT.
Ploughs are pushed by a tank or an armoured bulldozer. The plough relies on a set of parallel tines, pushed through the ground. Mines are scooped up by the tines and brought to the surface, being pushed off with a lot of earth to either side of the vehicle track by the angled plough blades. Several mines explode. Many are buried into the berm, and very difficult to remove later.
Plough in front of a tank (courtesy of Dr Ken Fyfe, Univ. of Alberta).

See his comprehensive description of mechanical means (http://www.mece.ualberta.ca/landmine.html).

Leopard tank in action.
Prodders dig out the mines with a rake, when they have been located. Mechem (South Africa, fax +27 12 803-7189) proposes such a rake at the end of an arm.
Safer than doing it by hand, but the vehicle will be seriously damaged if that antitank mine explode!
Prodding as used by deminers is an efficient method which needs a high sensibility, and is difficult to perform with a robot. A steel rod is used for probing the ground (at 30 degrees). The rod could be placed at the end of a robotic arm, with wrist sensors developed for robotic applications. The prodder could vibrate or rotate for an easier ground penetration. A sensor on the tip of the probe should provide information on the encountered materials. The vibrating probe is a project supported in 1995 by the DoD [Hambric95], but no results are published yet (June 96).
Several design projects for a multiple probing device carried by a remote-controlled 8-wheel vehicle are proposed at the University of Alberta (http://www.mece.ualberta.ca/landmine.html). A good idea is to have an heated probe tip, to help identify the located object (e.g., the plastic case of a mine will become soft and viscous).

Results of experiments with an accelerometer at the back of the probe are given. Three students supported by the DRES are continuing the work.

At the Croatian Ministry of Interior and the University of Zagreb, Davor Antonic and Igor Ratkovic have recently started to study the forces on a probe penetrating in the ground, planning to build later a mine probing robot (http://www.rasip.fer.hr/~d/KoREMA.html).
Explosive overpressure uses a fuel gas contained in a polythene tunnel, which is detonated. Many mines are made resistant to explosive overpressure.
Fire is sometimes used in minefields covered by dry grass. Buried mines are not affected, and most others remain dangerous. TNT is highly polluting when not destroyed by explosion.

Military sensor movers

Armed forces are interested in a vehicle travelling on a road at 20 km/h and detecting antitank mines. Metal detectors, GPR antennas are put in front of a teleoperated vehicle,

The Canadian Department of National Defense has a project ILDP (Improved Landmine Detection Project) [Hewish95]. The device consists of an array of ground penetrating radars, about 2 metres wide, in front of a vehicle having large tires. The purpose is to detect anti-tank mines (70 to 300 kg of activation pressure) on a road.

The similar vehicle proposed by Elta Electronic Industries (Ashod, Israel, fax +972 8 856-3930) in Israel has been selected by the US Army for extensive testing.

ELTA
The ELTA teleoperated vehicle.

Demining campaign vehicles

There is a need for vehicles to be used for carrying demining teams and providing a maximum of protection in case of accident. Mechem (South Africa, fax +27 12 803-7189) proposes vehicles [Mechem95] with metal wheels and boat-shaped chassis to better withstand explosions. Another light armoured vehicle is also used to collect vapour samples to be further analyzed by dogs.

Casspir A typical Mechem vehicle: the Casspir.

Humanitarian mechanical solutions

Many naive inventors have been proposing rollers, flails, hammers, not being aware of the insufficient reliability of mechanical solutions. Mechanical solutions can be used to identify mine fields and possibly remove most of them to accelerate the subsequent work of a sensor-based mine-detecting solution.

We also personally believe in the need for a mechanical solution to check a minefield where all mines are supposed to have been removed by a new technology of a not yet proven reliability. It will be very difficult to test any new solution and define its level of confidence. We favour the roller, and the only valid solutions we know of have been recently proposed by Prof S.H. Salter of Edinburgh University E-mail (shs@mech.ed.ac.uk).

The Dervish is a robot built with 3 wheels at 120 degrees actuated by independent compact hydraulic motors; a 125 cc motor generates the electricity for the electronic valves, as well as the hydraulic force for the motors. The steel wheels weigh about 80 kg, are 4-6 cm thick, and emulate rather well a human's leg.

Due to the position of the wheels, the Dervish can only turn on itself. Different motor speeds will make the Dervish's wheels describe spirals. A wide path can hence be stamped by a radio-controlled robot. In case of mine explosion, the wheel and the compact hydraulic motor should resist. The tetrahedral structure linking the three wheels and the central power source will be easily repaired.

Dervish
The Dervish proposed by S.H.Salter. A new design with two wheels at 90 degrees is under construction.

The Mattock is a very simple manually operated device, which could be made into a robot, should it prove to be too dangerous. A half-disk rolls from one side to the other and comes back to its central position. At its own resonance frequency, a minimum amount of energy is required to maintain the oscillation movement. A long bamboo stick (e.g., 6 m long) transmits the energy of a human operator from a safe distance. While the Mattock is oscillating, a horizontal movement of the handle makes the Mattock yaw and slowly move forward, pressing systematically every square inch, for a path width corresponding to the wheel size and the oscillation amplitude.

Mattock
The Mattock proposed by S.H.Salter (contact him or J.D.Nicoud before any implementation). S.H.Salter recommends to make the disk of soft steel. J.D.Nicoud made a test with the wheel built with water bottles. As shown in a report available by H. Salter, water is excellent to absorb the heat of an explosion. But the contact must be as good as possible, and the water wheel as tested, with the bottles being used both to provide the pressure and to be destroyed by the explosion, is inadequate.

The Hammer is a rough low-tech idea frequently suggested. The naive drawing below, made by J.D.Nicoud, is given here to stimulate better ideas, which could be developed in the countries plagued with mines. In addition to the vertical oscillating movement, there is a lateral scan of the width of the bicycle track. The drawback, supposing the operation sufficiently reliable and non dangerous, is a very slow progression (10 metres per hour).

Hammer

Prof James Trevelyan (Univ. Western Australia) proposes several ideas. One is to put the sensor and the hammer on a static robot with a long arm [Trevelyan96]. Having the robot fixed on the ground allows precise measurement of the position of the mines.

Another proposal of J.Tevelyan is to suspend the sensor and hammer with cables to three or four winch units at the edge of the mined areas.

Humanitarian sensor movers

The Pemex has been developed at the LAMI-EPFL (Lausanne, fax +41 21 693-5263). It is a lightweight vehicle (16 kg) which is not supposed to trigger the mines it detects. The motion is given by two wheels (bicycle wheels have been used for the prototype). When searching for mines, the Pemex head oscillates right and left, covering a 1 metre wide path. Technical info and pictures available courtesy of Ph. Maechler.

Pemex You can get an enlarged figure by clicking here and have access to other pictures.
Total weight is 16 kg, that is, a maximum of 6 kg per wheel, which should not trigger AP mines. The 70 W DC motors give to the vehicle a speed of 2 m/s and excellent cross-country capabilities.

The work on the Pemex will be resumed in cooperation with a company when a sensor system will be available. Work progresses anyway with students to improve of the structure, motors, and navigation sensors. It is clear that, as long as local deminers have no life insurance and are paid less than 1000 US$ per year, humanitarian demining team will not buy robots costing above 10'000 US$, including the sensors.

Others

Teleoperated robots save life, but are very expensive. The camera system used to observe the ground is far from having the resolution of the human eye. Adding a prodder in front of a robot is a dream.

Police Demining teams cannot justify the expenses for such robots, sold to affluent police departments of large cities.

Ariel Ariel prototype (from the Web reference below)

The legged underwater robot Ariel (http://www.isr.com/projects/ariel/default.html) is proposed by IS Robotics for searching mines in the surf zone using a population of randomly searching robots (project sponsored by ARPA).
IS Robotics also proposes a Highly Mobile Mine Marking, Mapping, and Detection system (HMMMMD, or Hum-De) (http://www.isr.com/projects/humd/default.html), designed to aid in the dismounted de-mining mission by providing a small ground based standoff vehicle.

Legged robot are proposed by the Royal Military Academy in Belgium within the Clawar project.

Cybernet System Corporation, Ann Arbour, has written a report suggesting the use of walking robots designed for Mars exploration for demining. They just ignore the sensor and the cost problems.

An original, but perhaps too expensive prototype, adequate for moving in marshland, has 6 wheels which are almost vertical when the soil is hard and flat in the mud. An additional proposal of J.Willer from Neu-Ulm (fax +49 731 7-5440) is to have the mine detectors inside the wheels.

Willer J.Willer's scaled-down prototype (60 cm long).

You can also see several drawings of simulated legged and caterpillar robots studied at the Naval Postgraduate School Monterey (http://cs.nps.navy.mil/research/eod/) and the one proposed by IS Robotics (http://www.isr.com/projects/fetch/default.html).

Within the PIRAIA project (http://www.sics.se/piraia/), a snake robot is proposed and one aim of the study is to develop a rough terrain for hazardous missions, such as mine clearing.

Surfing on the Web, you may find university projects which claim for demining activity in order to get funding. For instance, a student playing with a population of randomly-moving small robots claims that they are "Explosive Ordnance Disposal Robots".

Not a robot, but worth to mention, ODIS is an imaging induction coil sensor [borgwardt95] developed at DASA-Dornier (Box 1420, D-88039 Friedrichshafen) for the reconnaissance of buried metallic objects. The ODIS module contains a matched set of rotating detectors which scan 1 m in width at about 0.5 m/s. It is fixed in front of a Unimog.

ODIS The ODIS developed at DASA-Dornier carried by a Unimog.

Vegetation cutter

Vegetation is the major problem on most minefields, usually abandoned for several years. Big tanks may ignore the trees, but not most of the robots which are designed with cost-effectiveness in mind.

A solution experimented with success by HaloTrust and MGM is to use the kind of equipment used for clearing grass on the side of the highways: a long tele-operated arm carries a cutter. Halo-Trust added some wood sliders, so the wood will be destroyed in case the cutter triggers a mine.

References

References can be found in a separate html file (http://diwww.epfl.ch/lami/detec/refromine.html) which includes all the good references we are aware of from scientific journals and conference proceedings. If you have something which is missing in our list, please send us a copy of the missing item (J.D.Nicoud, LAMI-EPFL, CH-1015 Lausanne).

Another source of information on the Web is the list of general documentation on mines and sensors compiled by Claudio Bruschini. He also makes available a number of landmine related bookmarks, if you have time for surfing. A shorter list exists too, in case.

http://diwww.epfl.ch/lami/detec/rodemine.html | Last modified by CB 23.11.1997.

Current Status: completed (see the Home Page).

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Last update, April 19. 1997 | Current Status of activities: completed (see the Home Page). NOTE: This page contains some outdated material and is provided for historical reasons only (illustration of early ideas and developments). Do not use any of the suggested solutions.

Demining robots and vehicles

Last update, April 19. 1997 | Current Status of activities: completed (see the Home Page).
NOTE: This page contains some outdated material and is provided for historical reasons only (illustration of early ideas and developments). Do not use any of the suggested solutions.