Effect of Rotor Cant on Trim and Autonomous Flight Dynamics of a Quadcopter

Rotor cant is simulated on an SUI Endurance quadcopter. Two types of rotor cant, flapwise and torsional cant, are defined, and multirotor coordinates are used to define four aircraft-level modes of cant for each type. Collective flapwise cant causes an increase in collective control and power required, and a positive correlation exists between collective flapwise cant and pitch control. It also causes the longitudinal and lateral poles to retreat from the origin. Postive longitudinal flapwise and negative lateral torsional cant cause a reduction in nose-down attitude in forward flight, reducing drag and negative lift on the fuselage by 13% and 31% at 15 m/s, which reduces power required by 6% while increasing hover power by only 0.5%. Lateral flapwise cant and longitudinal torsional cant affect the roll attitude, though no power savings is available. Differential flapwise cant causes forward speed to impose a net rolling moment, which is compensated by roll control. Differential torsional cant is positively correlated with roll control. Both differential cant modes cause some poles to move toward the origin while others move away, but differential torsional cant can increase yaw authority by up to 325%.

Reference

Niemiec, R., and Gandhi, F., "Effect of Rotor Cant on Trim and Autonomous Flight Dynamics of a Quadcopter ,"

Proceedings of the 74th American Helicopter Society Annual Forum, Phoenix, Arizona, May 15-17, 2018.