Dynamics and Control of a Tilt-Motor Quadrotor
The paper presents a dynamical model and a control loop structure for an unmanned aerial vehicle (UAV) with four tilt-motors. The advantage of the considered quadrotor design over the standard models is full controllability because of additional servomotors, which allow tilting the four motors responsible for the thrust force. The mathematical model describes the dynamics of a complex system consisting of the UAV body and the four rotors. The system's center of mass dynamics is influenced by the gravity force, the aerodynamic drag force, and the thrust force generated by the rotating propellers. The rotational dynamics of the UAV's body is modeled with the account of the aerodynamic torque, gyroscopic torques, and the thrust force torques. The attitude of the system is described with the use of quaternions. The proposed control algorithm allows to independently control position and attitude of the UAV. The considered model also takes into account the sensor's signal errors, which are processed by the Extended Kalman Filter. Numerical simulations are carried out to endorse the correctness of the model and the control algorithms.
 Bouabdallah S., Noth A., Siegwart R. PID vs LQ control techniques applied to an indoor micro quadrotor. Proceedings of the IEEE / RSJ International Conference on Intelligent Robots and Systems. Sendai, Japan, 2004, pp. 2451–2456.
 Bouabdallah S., Siegwart R. Full control of a quadrotor. IEEE / RSJ International Conference on Intelligent Robots and Systems, 2007, pp. 153–158.
 Mellinger D., Kumar V. Minimum snap trajectory generation and control for quadrotors. Proceedings of the IEEE International Conference on Robotics and Automation (ICRA
 Andersson O., Wzorek M., Doherty P. Deep Learning Quadcopter Control via Risk-Aware Active Learning. AAAI, 2017, pp. 3812–3818.
 Adams S.M., Friedland C.J. A survey of unmanned aerial vehicle (UAV) usage for imagery collection in disaster research and management. 9th International Workshop on Remote Sensing for Disaster Response, January 2011, p. 8.
 Pudelko R., Stuczynski T., Borzecka-Walker M. The suitability of an unmanned aerial vehicle (UAV) for the evaluation of experimental fields and crops. Agriculture, 2012, no. 99 (4), pp. 431–436.
 Beard R.W., McLain T.W. Small unmanned aircraft: Theory and practice. Princeton University Press, 2012 [in Russ.: Beard R.W., McLain T.W. Malye bespilotnye letatelnye apparaty: teoria i praktika. Moscow, Tehnosfera Publ., 2015, 312 p.].
 Ryll M., Bülthoff H. H., Giordano P.R. A novel overactuated quadrotor unmanned aerial vehicle: Modeling, control, and experimental validation. IEEE Transactions on Control Systems Technology, 2015, no. 23 (2), pp. 540–556.
 Hua M.-D., Hamel T., Samson C., Control of VTOL Vehicles with Thrust-direction Tilting. Proceedings of the 19th IFAC World Congress, August 2014, 9 p.
 Sholc G., Trommer G.F. Giroskopiya & navigaciya — Gyroscopy and Navigation, 2015, no. 4 (91), pp. 131–146.
 Sridhar S., et al. Non-Linear Sliding Mode Control of a Tilting-Rotor Quadcopter. ASME 2017 Dynamic Systems and Control Conference, 2017, pp. V001T09A007–V001T09A007.
 Kumar R., et al. Tilting-Rotor Quadcopter for Aggressive Flight Maneuvers Using Differential Flatness Based Flight Controller. ASME 2017 Dynamic Systems and Control Conference, 2017, pp. V003T39A006–V003T39A006.