We design the navigation and control system for unmanned aerial vehicle (UAV) with four tilting rotors. The considered UAV implements the so-called X-sceme, which implies the main body and four symmetrical beams, upon which rotors with propellers are mounted. It is different from the classical quadrotor by having four additional servomotors that may change the orientation of the rotors with respect t the main body, thus increasing the control parameters number. Greater number of the actuators in the system, on the one hand, opens new venues for UAVs’ applications but, on the other hand, makes the mathematical model of the UAV’s dynamics quite complicated. The latter calls for new control algorithms to be developed. We start by forming the mathematical models of the UAV’s dynamics. It is shown that the introduction of the tilting motors allows implementing independent control of the quadrotor’s position and attitude. The control loop is designed on the base on the analytical dynamics inversion. The expressions for the control parameters thus obtained are subjected to the numerical analysis, which allows taking into account technical constraints for maximal motor speed and tilt angles. Feedback in the control loop is implemented by simulation of the on-board sensors’ signals, whose characteristics correspond to those of the sensors used in the UAV’s experimental prototype design. The signals are processed with the aid of the unscented Kalman filter algorithm. The results of numerical experiments corroborate the efficiency of the developed control and navigation algorithms. The mission simulated in the numeric experiments is tracking of a pre-defined trajectory and pointing with a body-fixed camera at a mobile object, which, in turn, moves along a programmed trajectory.The results of the numeric experiments show that the UAV is capable of performing complex maneuvers with independent position and attitude control.
Logical model of mobile object control
