Uncrewed Systems Technology 051 l Primoco One 150 l Power management l Ocius Bluebottle USV l Steel E-Motive robotaxi l UAVs insight l Xponential 2023 p Issue 51 Aug/Sept 2023 art 2 l Aant Farm TPR72 l Servos l Tampa Deep Sea Barracuda AUV

Servos | Focus Electrics While recent advances in small UAV electric motors and motor controllers have yet to feed into new types of motors for servos, there is a slight but noticeable trend towards higher voltages in actuation systems. Higher voltages mean a more energyefficient servo, as the high current rates needed for motor torque can be delivered more easily without significantly increasing energy losses through heat in the windings inside (or wires upstream of) the motor. As such, servo voltages up to 24 or 32 V are becoming increasingly common for UAVs across the 25 kg weight class and larger systems. In most UAV servos now, using a higher voltage does not require using bigger connectors or cables. In fact it can help with hardware design and servo lifespan by eliminating the need for regulators, as these are among the most failure-prone components in an actuator. In the future however, as UAM, HAPS and heavy UAV designs proliferate, actuators built for 300-400 V buses and higher will become increasingly widespread, with the 800-1000 V levels of the EV industry likely to follow as electric autonomous air freight and other applications needing extremely large vehicles become a reality. These will need heavier connectors, cabling and protection systems to go with the larger servo sizes, as electrical safety becomes paramount for integrators and technicians. Sensors Careful monitoring and maintenance of servos depends on installing and using quality sensors for feedback on operations and health. For the most part, sensors for parameters such as voltage and current are standardised, although a few innovations can be seen in areas such as speed or position sensing. For instance, advanced features such as the aforementioned torque limitation software cannot rely on current sensing to gauge the speed and torque of a servo. Current readings are extremely prone to noise interference from other electrical activity, and cannot therefore always be relied on to create a closedloop control system. Instead, deriving the speed of the servo from its position sensor – particularly a contactless position sensor using a method such as the Hall effect – can be far less prone to interference and will hence be much more reliable. Some actuator designs even integrate as many as three contactless position sensors, enabling triple redundancy and majority voting to make sure the speed and position of the servo are being read correctly. Contactless position sensing is increasingly standard among high-end servos because of their far longer lifespan than any sensor needing persistent contact and hence causing friction 20mm Case Servos North American Sales & Support San Diego, CA | www.hiteccs.com NON-CHINESE MANUFACTURING SOUTH KOREA • Research & Development • Engineering & Manufacturing UNITED STATES • Research & Development • Distribution, Sales & Support PHILIPPINES • Manufacturing • Logistics Stall Torque 60.0kgf•cm Wide Operating Voltage 8.0~32.0V Waterproof Case Rating IP67 MDB961WP Stall Torque 65.0kgf•cm Wide Operating Voltage 9.0~32.0V Waterproof Case Rating IP68 SG20BL INDUSTRIAL MULTIPLE COMMAND PROTOCOLS AVAILABLE: