Column: Airspace
Saving weight brings bigger returns in urban air mobility
By Mark Patrick, Director of Technical Content, Mouser Electronics W
ith their substantial power demand yet finite quantity of energy
available, urban air vehicles (UAVs) must be lightweight and highly efficient. Considering that the cabling on
board a modern road-going electric vehicle (EV) can be about 70kg, the additional needs of an electric aircraft can easily exceed this weight and therefore must be minimised. Approximately 1500kW is needed for take-off, which is several times the power of an average EV that requires heavier cabling – that’s just simply to handle the peak current at maximum load – and largely unavoidable. Put another way, UAV take-off
10 April 2024
www.electronicsworld.com
requires motor currents up to 250A, and can be higher in UAVs with larger rotors. The current determines the cable gauge and required insulation.
Cable-saving technologies Weight savings can be achieved by minimising the thickness and quantity of electrical cables in the airframe. Keeping thick cables as short as
possible and locating batteries and high-power circuitry close to the motor also helps. Technologies like Ethernet 10BASE-
T1L, already widely used in industrial applications, enable data and power to be transmitted over a single twisted pair, simplifying the factory’s network setup. It supports 10Mbit/s data rates and cable lengths to 1km. In urban airspace mobility (UAM) applications, this technology can also simplify sensor and
actuator interconnects throughout the aircraft, saving weight. Bus architectures like Controller Area
Network (CAN) are already proven in automotive and industrial applications, too. In an aircraft, proper attention should be paid to redundancy and failover safety, if a cable or connector gets damaged or becomes disconnected. Where a suitable power cable is
available, powerline communication is another way to connect devices: It can be used to connect sensors monitoring the condition of a motor by allowing signals to ride on the power cabling. Another option is to use a powerline
transceiver with RS-485 signalling with on-off keying (OOK) modulation, like the THVD8000 from Texas Instruments; see Figure 1. This type of modulation is agnostic to data polarity, allowing data rates of about 500kbit/s. This
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