Light Weight Collective Pitch Control Systems for Swashplateless Rotors

Orbital Research Inc proposes to design and optimize a light-weight swashplateless helicopter rotor collective control system. One enabling technology for swashplateless rotors utilizes on-blade controls to control the lift created by each rotor blade. However, a limitation of on-blade controls is that utilizing the individual blade lift authority for collective blade control diminishes the range available for cyclic blade control. A collective control system that primarily adjusts the root blade incidence angle gives increased lift without reducing the authority of the on-blade controls. To provide reduced complexity and weight Orbital Research proposes utilizing all-electric redundant harmonic drive actuators to drive a single mechanism capable of increasing the root blade incidence while maintaining integrated pathways for access to on-blade control mechanisms. Benefits of the harmonic drive actuators include: 1) No backlash, 2) high torque, and 3) simplicity. Because the harmonic drive actuators consist of DC motors and a low-volume, high-gear-ratio harmonic transmission, they are extremely reliable. This will result in a design with low mass, compact geometry, reduced complexity, easy maintenance and ballistic damage resistance.