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

capacity, and we don’t want to make either of those compromises.” Surprisingly, weight is just as critical for a small AUV as it is for its flying counterparts, because if it is to keep to its selected depth naturally – or even possess a slight tendency to rise – its weight must be exactly balanced or marginally overcome by its buoyancy. “Every gram on the vehicle that is not fulfilling an important function is lost potential battery capacity, so in the end any ballast you have should ideally be battery,” Schill says. Other work in progress is finalising the manufacture of the outer hull. Schill notes that they moulded the first ones in-house, but then had difficulty finding other manufacturers who could use the same process, so they are looking for other suppliers and processes. The surface finish may also change: the paint might be replaced with a plastic coating or some other option. “We have a solution for manufacturing the hulls; it is just more expensive than we’d like, and it doesn’t get cheaper with large quantities,” he adds. Propulsion and control Propulsion and control are intimately linked in the Vertex because both rely on using the five thrusters in combination. There are three horizontally mounted, vertically acting thrusters – one in the tail and one in each of the forward winglets – plus the main pair at the rear acting along the fore and aft axis. All are in fixed mountings and can only vary their speed and reverse their direction, but together they provide direct and positive control of motion in five axes: three in rotation and two in translation. Opposing the forward and aft horizontally mounted thrusters provides pitch control; opposing the left and right horizontally mounted thrusters gives control about the roll axis, while opposing the main generates yaw. Running together, the horizontally mounted thrusters provide control along the heave axis (straight up and down), while the main thrusters control the