Issue 37 Unmanned Systems Technology April/May 2021 Einride next-gen Pod l Battery technology l Dive Technologies AUV-Kit l UGVs insight l Vanguard EFI/ETC vee twins l Icarus Swarms l Transponders l Sonobot 5 l IDEX 2021 report

6 Mission-critical info for UST professionals Platform one ePropelled has launched a series of electronic controller units that work across starter/generators and propulsion motors for UAVs (writes Nick Flaherty). The controllers have a combination of functions that support both the motors and the generators via a CAN bus. This can provide greater battery life for longer mission time in several different ways, said Nabeel Shirazee, chief technology officer of ePropelled. The facility starts with the Intelligent Power System (IPS) controller. “The IPS takes the three-phase supply from the starter and provides a DC output with battery back-up,” said Shirazee. “We are monitoring the temperature from the starter/generator in the IPS, so if you are doing a lot of cranking you know exactly when to stop before the generator gets too hot. “The other aspect is that there are a lot of diagnostics, and we let users know via CAN messaging whether they are at upper or lower limits so that they can set different levels of alerts.” The CAN bus operates at up to 1 Mbit/s. “The IPS also allows the starter/ generator to operate as a propulsion motor, to assist the engine during take- off. If you use the starter/generator propulsion motor [SGPM], the starter/ generator can give the extra power for take-off and landing.” “When the SGPM has finished as a propulsion motor it can just generate power for the rest of the flight and go back into propulsion mode for landing, so you save a lot of weight. “The transition [from SG to PM] is handled by the electronic engine starter motor controller (EESMC), and you have the IPS next to it, so the EESMC starts the engine, runs as a propulsion motor, then backs off the motor controller and lets the IPS generate the power. The EESMC and IPS also talk to each other over CAN.” The controller for the motor is optimised for performance as well, and links to the IPS via a CAN bus. “We also have a propulsion system with an Intelligent Air Motor Controller (IAMC). How we control the propulsion motor is based on the type of propeller put on, and again we are monitoring the temperature of the motor up to the point of a warning, such as 150 or 170 C.” The IAMC can also control the phase of the voltage to the motor to boost the lifetime of the battery pack. “We monitor the battery voltage, and as the voltage drops the speed will drop, so we can manage that with our software in the IAMC in real time with phase control to increase the current to increase the speed as the voltage falls. The benefit depends on the battery size and battery voltage warning, but it can be anything between 10 and 20% extra battery life.” Airborne vehicles CAN units boost UAV battery life April/May 2021 | Unmanned Systems Technology The controllers support both motors and generators via CAN messaging