Intelligent Optimization Design Method Of Quadrotor UAV Structure In Coal Mine

The coal mine tunnel is narrow,long and closed,and the environment is complicated.More seriously,there is a large amount of toxic,flammable and explosive gases after the mine accident.The direct participation of rescuers may lead to unpredictable consequences.At present,most of the detection work for mine tunnels uses rail-type detection robots,but in post-disaster environments,rail robots cannot meet actual needs.Micro quadrotor unmanned aerial vehicle(UAV)is widely used in military and our daily life,due to the relative simple structure,vertical takeoff and landing,and its high mobility.In this thesis will use the quadrotor UAV as the design basis to design a small UAV that can meet the underground flying environment.However,owing to the narrow space of underground tunnel,there is a high demand for the overall structural design of UAV.Traditional structural optimization design relies too much on theoretical calculations and the experience of designers.It mainly uses a large number of finite element simulations to experiment with the structure of the UAV which is time-consuming and low in precision.The pros and cons of the design depends entirely on the designer’s experience.Therefore,the surrogate model is used to replace the actual finite element model,and the evolutionary optimization algorithm is used to solve the UAV problem,which provides a scientific basis for the design of underground UAVs,and ensures that the design program is scientific,feasible,accurate,and efficient.The main work completed in this article is as follows:This subject takes the structure design of the UAV as the main research object.A reasonable quadrotor UAV design can suit the actual engineering needs and play a vital role in the actual rescue and gas detection work.In contrast,the unreasonable design scheme has the risk of secondary accidents.For the overall structural design,it is mainly to ensure that the UAV’s flight is smooth,the cost is low and the structure is stable.Due to the mine tunnel is long and narrow,and there are many factors that affect the UAV’s flight in the coal mine.We mainly evaluate the reliability and economy of the program from the appearance of the drone itself.Eight parameters inside the UAV structure are selected as decision variables,and the optimization targets of the UAV are set as the UAV quality,UAV lift and UAV cost.The quality of the UAV and the cost of the UAV can be directly established by mathematical models.For the lift of the UAV,there is a highly nonlinear relationship with the decision variables.The surrogate model is selected to replace the expensive finite element model.This thesis selects the Kriging method and RBF to construct surrogate model.The key parameters in the surrogate model are selected and analyzed.The surrogate model with higher precision is selected to construct the UAV lift model after discussing the decision parameters of the surrogate model.Experiments show that the selected surrogate model can replace the finite element model,which improves the optimization efficiency.Aiming at the multi-objective problem of quadrotor UAV structure,the multiobjective mathematical model is constructed by the UAV quality,UAV cost and UAV lift,and the multi-objective evolution optimization algorithm NSGA-Ⅱ is used to solve the multi-objective optimization problem to obtain the pareto solution of the optimization scheme.The performance of the NSGA-Ⅱ algorithm is verified by comparing with the performance of the multi-objective particle swarm optimization algorithm.According to the actual engineering needs,formulate the plan in the Pareto solution.The optimal solution that can balance multiple optimization objectives are selected,and the design scheme is verified by the finite element simulation method to analyze the prediction accuracy of the model.The overall optimization effect of the final design is obvious,which has theoretical and engineering guidance significance for the optimization design of the underground quadrotor UAV.The experiment proves that the overall optimization effect of the drone structure is obvious,which can meet the actual engineering needs.In this thesis,through the construction of the surrogate model and the NSGA-Ⅱ algorithm,the intelligent optimization design of the four-rotor unmanned aerial vehicle structure in the coal mine is realized,which provides the designer with a scientific design method and has certain guiding significance for the future mine detection and rescue work.The thesis includes 29 figures,14 tables and 76 references.