Three-dimensional Printing Path Planning Method For Large-size Free-form Surface Conformal Antenna

Sensor aircraft is an unmanned aerial vehicle used in combat environments.It adopts the idea of integrating sensors into aircraft to construct a sensor-aircraft that employs the sensors as structural parts.The antenna that collects radar signals and electrical signals serving as a carrier to become part of the fuselage structure.The traditional conformal load bearing antenna manufacturing process has many steps,complex processes,expensive equipment,and low yield,which have bottlenecked its development.3D printing technology can provide a better solution for these problems.In the background of 3D electronic integration,the application of 3D printing technology to prepare sensor aircraft antennas has become a highly potential manufacturing method.How to integrate a large-size antenna into the airframe is a key and difficult problem in the research of sensor aircraft.In response to the above problems,this thesis proposes a path planning method for array nozzle for 3D printing of large-scale free-form conformal antennas based on the principle of differential geometry.Simultaneously,interference inspection and droplet coverage processing of the array nozzle are studied.The main work of this thesis is as follows:(1)Aiming at the 3D printing of large-scale free-form surface conformal antennas,a path planning method for array nozzle based on offset curves on the curved surface is proposed.A series of curved surfaces generated by this method represent the path of the array nozzle,and the planned path can completely cover the entire surface of the substrate.First construct the initial path on the substrate,which is obtained by intersecting the reference plane determined according to the printing direction with the substrate to be printed;then,offset the initial path,including the selection of the offset direction and the calculation of the offset distance,and use the offset path as the new reference path;repeat the offset until the generated path can traverse the entire substrate.(2)In order to solve the local interference between the array nozzle and the substrate,an interference inspection method based on the curvature radius of the curved surface method is proposed.The minimum normal radius of curvature is compared with the print limit length of the array nozzle,combined with the unevenness of the curved surface where the point is located,to determine whether the array nozzle will have curvature interference around the point.In order to solve the global interference between the array nozzle and the substrate,an interference inspection method based on the minimum distance between the array nozzle axis and the substrate is proposed.By calculating the minimum distance from the bottom surface of the array nozzle to the substrate,and comparing the distance with the lower limit height of the array nozzle,it can be judged whether there is a collision between the array nozzle and the substrate.(3)The droplet coverage treatment is to solve the problem of droplet coverage defects at the junction of two adjacent printing paths.By comparing the distance between the center lines of the two printing paths and the half length of the two printing bandwidths,it can be judged whether there is an overlap or gap at the junction of adjacent printing paths.If there exists an overlap or gap in the printing path,the array nozzle should be controlled to eliminate the coverage defects at the junction.For the 3D printing path planning method of large-size free-form surface conformal antennas,a non-equidistant offset path planning method is proposed.Simultaneously,detailed interference inspection and droplet coverage processing methods in the conformal printing process are established.It ensures that the conformal antenna is efficiently and accurately co-formed on the curved surface,and provides great research value for the application of conformal antennas in the aerospace field.