Unmanned Systems Technology 016 | Hydromea Vertex AUV | Power management systems | Unmanned Space Vehicles | Continental CD-155 turbodiesel | Swift 020 UAV | ECUs | DSEI 2017 Show report

7 Platform one Unmanned Systems Technology | October/November 2017 While many sense-and-avoid technologies for UAVs are based on image processing techniques, these naturally require reasonably good visibility to be effective. However, smaller UAVs may not be big enough or have enough processing power to support a computer vision or phased array radar- based system (writes Peter Donaldson). That is why uAvionix has taken a different approach to the problem, with a patent for a gimbal-mounted continuous wave radar-based obstacle, collision and terrain avoidance radar for compact autonomous or semi-autonomous UAVs. The design centres on a low-power short-range radar mounted on brushless gimbals that enable movement about the pitch, roll and yaw axes. The idea is to provide track-ahead detection of obstacles before the UAV changes heading or altitude, or a view below the UAV’s flight path for altitude and terrain sensing during a landing approach, for example. Not only do the gimbals increase the radar’s field of view, they also enable it to centre on a detected obstacle, independently of the UAV’s flight path, to identify it more clearly under the control of the UAV’s integral processing. The radar would be able to receive flight plan data from the UAV signalling a planned change of heading or altitude and adjust its angular orientation, field of view or effective range accordingly. The maximum range for track- ahead detection is quoted as 150 m or so, while that for landing assistance including altitude measurement, obstacle avoidance and level landing site selection is anticipated to be about 10 m. The radar will probably have interfaces with the UAV’s onboard controller, navigation and positioning system, an onboard obstacle database and a secondary surveillance radar receiver to monitor ADS-B signals, for example, from other aircraft, ground vehicles or ground stations nearby. The radar itself would generate a continuous stable-frequency signal, probably in the millimetre wave band to be able to ‘see’ through dust, haze, dazzling sunlight or fog for example. It will exploit Doppler processing to gauge the size, shape and proximity of obstacles to enable the UAV to manoeuvre around them, and if possible establish their identity. Radar plan for small UAVs Collision avoidance Actuators from Volz Servos have played a key part in a record-breaking solar UAV flight across the Atlantic (writes Nick Flaherty). The 6 kg, 5.69 m wingspan AtlantiKSolar UAV was developed by the Autonomous Systems Lab at the Swiss Federal Institute of Technology Zurich using Volz’s DA 15-N actuators and solar cells from Sunpower. The DA 15-N is a 15 mm (0.59 in) wide ‘micro-actuator’ with brushless motor and contactless position sensing which Volz said makes it immune to wear, vibrations and shock loads. It was designed especially for use in harsh environments and safety-critical applications that require an actuator with high endurance. For the solar power, the 88 E60 cells supplied 60 cylindrical high energy density lithium-ion batteries from Panasonic, which also powered a Pixhawk PX4 autopilot, an ADIS16448 10-degrees of freedom IMU, a u-blox LEA-6H GPS receiver and a Sensirion SDP600 differential pressure sensor. The UAV covered 2338 km across the Atlantic in 81 hours, a major improvement on previous solar-powered UAV systems. Also using DA 15-N actuators is Textron Systems’ unmanned systems division, on its Aerosonde Mk4.7 small UAS, which since 2010 has clocked up more than 200,000 flight hours. Airborne vehicles The AtlantiKSolar’s Voltz actuators helped it on its way to a solar flight record Servos earn flying colours