Research On Heading Control Allocation Of Multi-propeller Solar UAV

High-altitude Long-endurance solar unmanned aerial vehicle (HALEsolar UAV) received extensive attentions because of the characteristicssuch as long flight time, inexhaustible solar energy sources. Meanwhile,these features also make the solar UAV have a very broad applicationprospects in the military and civilian fields.Solar power is the main energy source of the HALE solar UAV whichis characterized by large scale, high aspect ratio, distributed propulsionsystems, and low-speed. Distributed propulsion systems bring differentcontrol problems for UAV. For example, large-scale requires the modulardesign of energy system and more constraints in terms of energy should beconsidered as the solar takes great part in energy supply.The special problems encountered in the course of solar UAV controlwere analyzed and solved, and the key aspects of the study included thefollowing three aspects. Firstly, a six-degree of freedoms nonlinear modeland a linear model were established to lay a foundation for the subsequentcontrol problem. Secondly, longitudinal and latitudinal controllers weredesigned using the classical PID method. The heading control was realizedby adjustment of rudder, propellers and the combination of rudder andpropellers respectively. The pseudo-inverse method, redistributedpseudo-inverse method, weighting pseudo-inverse method, daisy-chainmethod and quadratic programming method were respectively selected tosuccessfully accomplish the UAV s heading control. Then, the advantagesand disadvantages of these control allocation methods were analyzed andthe strong capability of disturbance-rejection. of heading controllers was proved. Thirdly, with the consideration of the properties of high aspectratio, multi-propeller solar of UAV, modular energy management methodwas discussed. A model of output of solar power was built. Potentialenergy storage approach and charge and discharge model storage batterieswere analyzed. Based on the modular energy management system andvariation of solar energy every moment, pseudo-inverse method withvariable weight and redistribution pseudo-inverse method with variableconstraint were proposed to realize heading control.The simulation results reveal that depending on the different actuatorsof the multi-propellers of the UAV, the stages and situations of flight, thedifferent control allocation methods and optimize functions in appropriateways can be selected to improve the efficiency and robustness of theheading control. The heading control methods proposed have certainsignificance in the future research of design of multi-propeller solar HALEUAV.