Research On The Design Of Mechanized Harvesting Device And Harvesting Trajectory Planning For Aquatic Vegetable Brasenia Schreberi

Brasenia schreberi is an aquatic plant with high economic value.In addition to its young shoots,which are edible,the mature leaves can also be supplemented with medicinal uses and the production of skin care and cleaning products.In the production of Brasenia schreberi,harvesting is the most laborious,time-consuming and labor-intensive part of the process.At present,the harvesting of Brasenia schreberi relies entirely on manual work.The research and development of Brasenia schreberi picking devices and the automation of Brasenia schreberi picking are of great significance to liberate labor and accelerate the construction of agricultural mechanization.In this paper,through the investigation and analysis of the characteristics of Brasenia schreberi in the actual Brasenia schreberi fields and the Brasenia schreberi picking process,an unmanned boat design scheme was proposed for the picking of mature Brasenia schreberi leaves on the water surface,focusing on the mechanical structure design of the walking drive mechanism,the end picking actuator and the picking robot arm of the picking unmanned boat,and the trajectory planning study of single and multiple leaves picking was carried out based on this unmanned boat,realizing the picking process.The specific research work is as follows.(1)Based on the field research of Brasenia schreberi fields and the experimental results of the shear mechanical properties of aquatic plant stems,an unmanned Brasenia schreberi picking boat scheme with a bright wheel boat as the walking mechanism was determined.The mechanical structures of the open-wheel boat,six-degree-of-freedom robotic arm and end picking actuator were designed,in which the working principle and size determination of the end picking actuation were introduced in detail,and the mechanical structure of the end actuator was optimized and verified by using ADAMS software for optimization simulation.The final determination of the shape size of the bright ship is 3500×1600mm,the maximum travel speed of the bright ship is0.5m/s;the arm span of the six-degree-of-freedom robot arm is about 1000mm;the maximum opening and closing distance of the end picking actuator is 36.6mm,and the spacing between the blades is 52.2mm.(2)The kinematics study of the Brasenia schreberi picking robotic arm was carried out,the kinematic model of the Brasenia schreberi picking robotic arm was established based on the D-H parameter method,the kinematic inverse solution of the Brasenia schreberi picking robotic arm was obtained by the algebraic method,and the MATLAB program was designed to build the simulation model of Brasenia schreberi picking to verify the correctness of the kinematic equations.In addition,the picking workspace of the Brasenia schreberi picking robotic arm was derived by combining the Monte Carlo method simulation.(3)A “fast approach,slow picking,and smooth motion” picking scheme was proposed for picking leaves of Brasenia schreberi,and the picking paths of single and multiple leaves were investigated separately.For a single leaf of Brasenia schreberi,a trajectory planning method combining quintuple polynomial and linear interpolation was used;and a MATLAB program was written to communicate with the vision and robot arm controller modules,and the target position obtained by vision was used as input,which was converted by the trajectory planning program into information on the movement angle of each joint of the robot arm.For multiple Brasenia schreberi leaves,three path planning algorithms were compared,including ant colony,genetic and simulated annealing,MATLAB programs were written for the three algorithms,and it was simulated and compared for the shortest motion path with 89,127 and 173 leaf position points respectively.The simulation results show that: with 89 target points the path planned with ant colony algorithm is the shortest,and the shortest path is 8375.79 mm,which is 36.12% and 29.12% less than genetic algorithm and simulated annealing algorithm respectively.The shortest path is 8375.79 mm,which is 36.12% and 29.85% less than the genetic algorithm and simulated annealing algorithm respectively.The simulation results also show that with 127 and 173 target points the shortest motion path is planned by the ant colony algorithm.And the parameters of the ant colony algorithm were selected by simulation experiments,and the parameters were finally determined as m=50,α=1,ρ=0.7,β=4.5,Q=200.(4)An indoor Brasenia schreberi harvesting experimental platform was built,and single and multiple Brasenia schreberi leaves were harvested to verify the harvesting effect of the end harvesting actuator and the trajectory planning effect of the robotic arm.The single Brasenia schreberi leaf picking experiments showed that the robotic arm can basically complete the motion requirements of "fast approach,slow picking,and smooth motion",and has a better picking effect on the Brasenia schreberi leaves with a short diameter less than 80 mm and the angle between the rhizome and the leaf plane greater than 20°,and the picking time is about 25.5s/each,and the picking success rate is 65.63%.The multiple Brasenia schreberi leaves picking experiments showed that: the ant colony algorithm based on optimized parameters can meet the picking task of multiple leaves.