Multi-domain Unified Modeling And Multi-objective Optimization Design Of Quad-rotor Aircraft Based On Modelica

Quad-rotor aircraft is an excellent,flexible,innovative vertical take-off and landing Unmanned Aerial Vehicle which has important scientific value and broad market prospect.However,due to its high control difficulty,low actual load and short flight time,the development of the quad-rotor aircraft was extremely slow in the past 100 years.The quad-rotor aircraft system is a typical multi-domain system,involving many fields such as motor,aerodynamics,modern control theory.For the construction of multi-domain models,the usual way of traditional single field simulation methods is to model each domain separately by different softwares and then integrate them,which can lead to poor model system coupling degree and low simulation accuracy and efficiency.This cannot be qualified for the unified design and analysis of complex electromechanical systems.Based on the original model,this paper firstly use the multi-domain unified modeling method to add the aircraft dynamics model,and carries out the multi-domain unified modeling of the quad-rotor aircraft.The Latin Hypercube method was used to design the experiment,and the flight performance of the quad-rotor aircraft is optimized by using the NSGA-II multi-objective genetic algorithm.The main work of this paper is as follows:(1)The development process of the quad-rotor aircraft and its current status of research are described,and the multi-domain unified modeling method and optimization design are reviewed.(2)Referring to the domestic and foreign literature,the structural form and flight principle of the quad-rotor aircraft are reviewed.Based on the original kinematic model,the dynamic model of the aircraft was added.(3)The multi-domain modeling of quad-rotor aircraft was built on the multi-domain unified modeling platform MWorks by using Modelica language.Compared with the prototype system,the error was found within 3%,the correctness of the multi-domain unified model was verified by the simulation experiment.(4)The flight performance of the quad-rotor aircraft was simulated by Latin Hypercube design,and multi-objective optimization method NSGA-II was used to obtain the Pareto optimal solution for multi-objective optimization problems.Compared with the prototype system,the optimized quad-rotor aircraft not only reduced the quality of 1.4%,while the maximum flight speed increased by 37%,the minimum hovering speed of BLDC reduced by 20%.