Research And Design Of UAV Airborne Geophysical Equipment

With the decrease of surface mineral resources,the state puts forward the strategic policy of deep exploration.With the rapid development of UAV technology,airborne geophysical technology has a new development direction,which can solve large-scale,high-resolution operations.As an efficient,low-cost,large-scale and less disturbed geophysical method,airborne geophysical exploration is becoming more and more popular.In recent years,multi parameter and high precision aerogeophysical comprehensive research has been widely carried out in various metallogenic belts.Especially,the measurement system based on UAV can widely adapt to different terrain and geographical environment,and obtain high-quality airborne geophysical measurement data.Based on the national key research and development program-"research and development of intelligent geophysical special rotor UAV system",this paper carries out the research and design work of the full axis gradient carrying device and the hanging carrying device against the background of the airborne geophysical system.According to the requirements of various indicators in the project,the structural design of the full axis gradient carrying device and the hanging carrying device has been completed.With the help of the finite element analysis software,the static and dynamic analysis of the full axis gradient loading device is completed,and the weak part of the system is optimized.Based on the results of the finite element analysis,a lightweight optimization design is carried out to reduce the weight of the support frame to reduce the load of the unmanned helicopter and enhance the maneuverability of the helicopter.The research work completed in this paper mainly includes the following parts:(1)This paper introduced the characteristics and research status of different kinds of airborne geophysical exploration systems,summarized the structural characteristics of typical products at home and abroad,and expounded the research significance and main research contents of this paper.(2)Based on the theory of composite materials,the mechanical properties of composite laminates were analyzed,which provided a theoretical basis for the design of all axis gradient loading device.According to the project requirements,the overall layout of the full axis gradient loading device was determined,and the strength and rigidity of the transverse probe rod of the full axis gradient loading device were calculated and checked.(3)In this paper,the actual working condition of the full axis gradient loading device was analyzed,and the stress of the transverse and longitudinal probe rods under the static working condition was simulated by using the finite element analysis software.The finite element analysis results of the simplified model of the transverse probe rods were compared with the theoretical calculation results,which proved the accuracy of the finite element modeling.(4)According to the design requirements of relevant industry standards and projects for the onboard device,the modal analysis and random vibration analysis of the longitudinal probe and the transverse probe of the full axis gradient device were completed,the weak part of the longitudinal probe was optimized and improved,the natural frequency of the overall structure was improved,which avoided the excitation frequency range of the helicopter and prevented resonance happen.(5)According to the functional characteristics and structural design requirements of the hanging and carrying device,the structural design and finite element analysis of the hanging and carrying device were completed.The variable density method was applied to realize the topological optimization of the hanging and carrying support structure.Taking the strain energy and volume of the support as the design response and the objective function as the minimum strain energy,the topological optimization results of the hanging and carrying support were obtained Before optimization,the weight was reduced by 15.46%.The finite element analysis of the optimized support frame proved that the optimized support frame met the requirements of actual working conditions.The design of the full axis gradient carrying device and the hanging carrying device meets the requirements of the project.The research results of this paper laid the foundation for the practical application of the geophysical carrying device in the aerial geophysical exploration of the unmanned helicopter,and provides a reference for the research and design of the same kind of device.