By Paolo Valpolini
The Unmanned Ground Vehicles (UGVs) arena is seeing every day new systems being added to the already consistent number of UGVs available on the market. Among OEMs that are active in that field we find Nexter of France, which started with small reconnaissance ground robots, the Nerva family, then installed its weapon systems on third parties unmanned chassis, and now has exhibited for the first time its own MULE concept, all developed in house. In fact the ULTRO was already shown at a couple of French Army events, but SOFINS, the Special Operations Forces Innovation Network Seminar, organised by the Cèrcle de l’Arbalète at Camp de Souges, north of Bordeaux, has been the first public event that saw the participation of this new UGV.
This electrically powered 4×4 unmanned system was designed in close cooperation with French forces, an iterative loop having been put into place during the development phase. At the front of the chassis we find, in the centre, a thermal camera and a daylight camera, while right and left 3D cameras are fitted providing obstacle awareness and allowing follow-me operations. A low light level camera is fitted at the back, while on the side of the chassis two cameras per side are fitted. The UGV is fitted with a Bren-Tronics 6T Li-Ion battery pack being hosted in a sliding compartment which allows to easily remove them. The battery module is fitted with a heating system, which in case of cold weather limits the efficiency reduction of the batteries, the power balance between energy used to warm the compartment and loss of energy being of course favourable. Nexter established a tentative mission profile in cooperation with the military, and the average endurance is estimated at 8-12 hours. When the unit needs to travel long distances, wheel hubs can be easily disengaged freeing the wheels, while tow bars can be pulled out, the ULTRO being thus towed behind the Infantry Fighting Vehicle until the deployment area is reached, considerably increasing not only the endurance but also the operational speed, the UGV batteries being capable to be reloaded while under tow.
When travelling autonomously the ULTRO can reach 18 km/h; it is fitted with Michelin Non-Pneumatic Tires (NPTs) that proved to perform very well on cross country terrain, the UGV being able to cope with 40° sloped and 35% side slopes, while it can overcome 400 mm vertical obstacles and ford up to 600 mm. As both axles are steerable, the ULTRO can pivot on itself, which makes it very agile, also due to its limited dimensions, Nexter’s UGV being 1.97 meters long, 1.30 meters wide and 1,18 meters high, the flatbed being at 0.9 meters height. The chassis is designed to be easily fitted with a mission module, the operation requiring only 6 bolts to be screwed. The vehicle has a weight of 800 kg unloaded, the payload allowed being 600 kg. At SOFINS the ULTRO prototype was fitted with the transport module, which has four folding side walls, lateral ones being useful also as emergency litters, to get out from sand traps, or to overcome vertical obstacles, increasing the obstacle maximum height from 400 to 600 mm. Other modules are available such as dismounted infantry battery charger, observation fitted with a telescopic mast, sensor carrier, etc.
Current modes of operation include tele-operation, follow-me, either man or vehicle, back on track, and trajectory replay. Nexter considers the ULTRO a technology demonstrator, on the way to a real product.
Photos courtesy P. Valpolini