Unmanned Systems Technology 001 | UAV Factory Penguin C | Real-time operating systems | Hirth S1218 two-stroke twin | Base stations | ASV C-Enduro | Composites | Datacomms

59 The ASV C-Enduro | Dossier supplied (via the pump’s fuel rack) to the single injector. The fuel rack is infinitely adjustable via an electric servo actuator. There are three elements in the control of the engine – fuel flow rate (pump rack) and the voltage and current produced by the electrical machine. The crankshaft speed in efficiency or power operating mode is a function of the fuelling and the load imposed on the engine by the integrated electrical machine, both of which are under the control of the CAN ECU. The load is in turn primarily a function of the battery charging requirement (current can also go direct to the propeller motors). The Hyperdrive control unit The CAN ECU is described by Irish as “a very durable automotive-spec controller, developed in-house, with all the code written by us.” In summary, the CAN ECU controls the diesel engine lift pump, the engine fuel rack and the engine cooling system. It also controls the power electronics for the associated generator and the power electronics for the two traction motors, as well as the output of the solar panels and the wind turbine. In addition, it controls the BMS, which in turn interfaces with the BFG. The CAN ECU governs the current in the dc supply system, which links the various electrical elements, and also governs the dc-to-dc controllers that ensure the right voltage is supplied to each subsystem on the vessel. The CAN ECU has control algorithms to manage energy generation, storage and power flow, propulsion motor control, safety functions and auxiliary equipment control. It is the controller for the entire propulsion system, including, for example, battery operation. In turn, the ASV controller at the top of the command chain governs the parameters within which it operates the system. For example, if it asks for 2000 rpm on each propeller, the CAN ECU controller will govern how that is obtained by the propulsion system. If the boat is in autonomous operating mode and the battery is becoming depleted, the CAN ECU will govern how it is recharged. It looks after the entire operation of the propulsion system in line with the operational requirements set by the ASV controller, which at all times is aware of the operation of the propulsion system and can override the CAN ECU if that is deemed necessary for any reason. The CAN ECU arbitrates between the different sources of energy and, for example, can send power from the generator direct to the traction motors and/or to the battery, and can isolate the battery for safety reasons if it’s full. “The battery is often one of the most critical elements of any system,” says Shaw, “so you have to protect it at the expense of everything else.” Conclusion The C-Enduro is an example of what can be achieved through unmanned systems technology when the absence of human cargo is fully exploited. It can go to sea for months at a time, where it can sit unobtrusively and therefore in the best possible situation to monitor its surroundings. Its combination of concept, advanced propulsion system integration and hydrodynamics give it standard- setting range and duration performance. ASV’s managing director Dan Hook concludes, “ASV is driving the transformation of autonomous vehicle design and operations, and we have worked hard and fast to develop the C-Enduro using some excellent UK engineering companies. Dozens of organisations around the world have been following the C-Enduro’s development and we look forward to a really exciting future for this capability.” Unmanned Systems Technology | November 2014 The battery is often one of the most critical elements, so you have to protect it at the expense of everything else The Hyperdrive CAN ECU runs the C-Enduro’s sophisticated propulsion system