A novel multicopter with improved torque disturbance rejection through added angular momentum

Abstract

This paper presents a novel multicopter design with an additional momentum wheel. The added angular momentum reduces the vehicle’s sensitivity to torque disturbances compared to a conventional multicopter. The mechanical design, coupled with intelligent feedback control, allows for operation of autonomous aerial systems in challenging environments where conventional designs may fail. Sensitivity to torque disturbances is shown to monotonically decrease with increasing angular momentum, and the effect scales such that a greater improvement in torque disturbance sensitivity is experienced by smaller vehicles. For a fixed vehicle size, a trade-off exists between the added torque disturbance rejection capability, the power required to carry the wheel’s added mass, and the kinetic energy of the rotating wheel. A cascaded controller structure is proposed that accounts for the additional angular momentum and that accelerates or decelerates the momentum wheel to gain additional control authority in yaw. Theoretical results are validated experimentally using two vehicles of different scales. The proposed vehicle design is likely to be of value in situations where precision control is required in the face of large disturbances.