New electric actuators for aerospace
Novel actuator designs for transferring helicopter control signals to the main rotor blades could improve high-temperature performance and reduce weight and emissions. Safer air transport with reduced maintenance and lower fuel consumption will enhance the competitiveness of the EU aerospace industry. EU-funded scientists working on the HPEM (Development of key technology components for high performance electric motors) project exploited new permanent magnet motor and position sensor technologies. The electrically powered actuators were targeted as integral parts of an electromechanical system to control the swashplate of the main rotor of a medium-sized rotorcraft. These systems were designed to yield high power density and improved fault tolerance. Researchers selected an alloy comprising silicon cobalt and iron for use in motor magnetic circuits, providing high saturation magnetisation and reduced losses. Using finite element techniques for modelling different motor configurations, they showed that motors magnetised circumferentially have better thermal properties. At the critical design review, the team selected insulating motor materials that could withstand high temperatures (up to 200 °C). It used mica-based components, winding wires enamelled with aromatic polyimide, mica-reinforced Nomex for slot insulation and a samarium-cobalt alloy for the permanent magnets. Selection of the rotary position sensor – resolver – technology was based on its capability to withstand thermal shock under different operating conditions. Optimal winding configurations and their segmentation strategies were evaluated in terms of electromagnetic, fault tolerance and thermal behaviour. Single-layer winding configurations were ultimately favoured as they demonstrated better thermal behaviour. HPEM's electric actuator technology for helicopter rotor blade control addresses EU goals of more electric, more reliable and greener air transport. Integrating electrically powered speed and position sensors should also enhance capabilities for engine monitoring and diagnostics. The team made sure to spread the word to industry, certification bodies, national policymakers, schools and EU citizens.
