Research On The Flight Performance And Operation Area Evaluation Of Plant Protection UAV

As a new type of agricultural machinery platform,the UAV has many advantages such as flexible control,can be hovering in the air,easy to carry and so on.It has been widely used in plant protection in agriculture.But there were no uniform industrial norms and standards for the production and sale of agricultural aircraft,and the aircraft performance is not clearly defined.It is not conducive to the healthy and orderly development of agricultural aviation plant protection industry.Therefore,it is necessary to study and develop the flight performance and operation quality evaluation system of the plant protection UAV,and use the system to test and appraise the performance indicators of the agricultural aircraft platform to assess whether it meets the actual needs of the corresponding areas of agricultural production and management.So as to standardize the management,technical identification and better guide its development for China's agricultural aviation construction and development of detection and identification of technical services.In this paper,the research on the the key technologies about monitoring and evaluation of plant protection UAV performance,the assessment of route planning capability and the reconstruction of operational map were carried out.The specific research contents are as follows:(1)A real-time monitoring and evaluation system for UAV flight status based on LabVIEW was designed.The “IG-500N” was used to collect the flight status of the UAV.The data collected and pre-processed by “STM32F103ZE” was transmitted via the wireless transmission module “GE MDS EL805” to PC.Based on LabVIEW,the software program was designed for processing,analysis and display of the flight status parameters.A route processing smoothing algorithm and flight path deviation algorithm were proposed.The accuracy of the sensor,the performance of the UAV flight monitoring and evaluation system and the control level of the flying control were tested.The results shown that this system can accurately obtain rich real-time flight status and realize the visualization of the data.The output of the test system was reliable,which can be used as a reference for the evaluation of the performance of UAV or the control level of flight controllers.(2)In order to evaluate the capability of flight planning of plant protection UAV,a coverage path planning software was designed.This paper analyzed the planning method of coverage path of traditional agricultural machinery,determined the coverage path planning method of "reciprocating",and decomposed the path planning into the planning of the starting point,turning points and ending point.The minimum parallelogram rule and the abscissa extreme value of turning area were proposed,and the coverage path planning methods under different situations were analyzed.The evaluation indexes included the total length of the route,the number of turns,the redundancy coverage,the re-spray rate and the leakage rate.The method of calculating the route evaluation indexes was studied,and a route evaluation method based on weighted score was proposed.The software was tested for a pentagon land,the experiment results shown that the total length of the route is reduced by 39.41 m which is 15.49% of its own.It also shown this algorithm can be used for automatic route planning for plant protection UAV,also can be used to extract the detected operating parameters of the route planning object to evaluate the ability of route planning.(3)This paper analyzed the main methods of coverage area evaluation of plant protection UAV,and put forward a map reconstruction algorithm for plant protection UAV based on breakpoint segmentation.Firstly,the problem of operation quality evaluation was simplified as the construction and consolidation of the operation coverage sub-region,and the ideal model of the construction of the sub-area was described.The breakpoint was defined.The breakpoints and the intersection lines can be extracted according to the binarization result of the vertexes of the region.The vertexes of the region were divided into several effective connection segments by using the breakpoints.This paper analyzed all the cases where the two lines intersect,and then set the rules of intersection points of the intersection lines.Based on the number of breakpoints in the two regions,the region merging rules were formulated under different conditions.A software was designed based on the algorithm,and experiments were carried out with the theoretical route,straight route and irregular route.The results shown that this algorithm are consistent with the theoretical calculation with the maximum running frequency of 25 Hz.(4)In order to solve the problem that two regions intersect at non-breakpoints,an algorithm based on effective intersection was proposed.This algorithm firstly solved all intersections between boundary lines of two regions and extracted the intersection lines.The deletion rules of the multiple intersections were made according to the vertex validity of the intersection lines.Vertexes of the region were divided into several effective regional vertex connection section according to the indexes of the remained intersection lines.Then,we choosed the regions with fewer multiple intersections as the active area,and formulated different region merging rules based on the number of effective intersections.A software was design based on this algorithm,and experiments were carried out with the theoretical route,straight route and irregular route.The results shown that this algorithm are also consistent with the theoretical calculation and the maximum running frequency is 189 Hz.(5)In order to construct the operation map completely,a regional merging algorithm based on boundary meshing was proposed.Firstly,the grid scale was defined,and meshing rules of the regional vertexes were established.One of the grid of the vertexes was defined as the starting grid,and the rules of grid classification were established.Then all the boundaries can be transformed into a grid sequence.The grid sequence was divided into effective grids,invalid grids,coincidence grids and overlapping grids.Then the grid sequence was divided into several effective grid connection segments by using overlapping grids.Finally,based on the number of effective grid connection segments in each region,the grid connecting rules between two regions were formulated.A software was design based on this algorithm,and experiments were carried out with the theoretical route,straight route and irregular route under different grid scales.Experiment results shown that there were a few error,the operational speed was slow because of the grid scale.The larger the grid scale was,the smaller the error was,and the slower the operational speed was.Finally,the advantages,disadvantages and applications of the three operation map reconstruction algorithm were compared and analyzed.