Study On Structural Characteristics Of Potato Tuber-Root Model And Design Of Reconstruction Algorithms

Excavating components are part of the key components of potato harvesting machinery,and the design of the excavating components directly affects the performance of the entire machine.The interaction between soil-tuber-root aggregates and excavation components is the basis of designing excavation components.In order to make sure that the theoretical basis of the design of potato excavating parts is more reliable and the simulation analysis is more in line with the actual situation,it is necessary to establish a reasonable potato tuber-root model.This paper relies on the project of National Natural Science Foundation of China "Study on Dynamic Fracture Characteristics of Soil-Potato Tuber-Root Aggregate and Its Coupling Mechanism with Excavation Shovel(51505305)".According to the biological characteristics of potato tuber-root system,the characteristic parameters were determined and obtained by field measurement during the harvest period of potato.The spatial coordinates of root axis were obtained by simulating the growth of root tips,thus the tuber-root model of potato was realized.The visualization module of potato tuber-root model based on characterization parameters was established by using object-oriented programming technology of MATLAB.The main research contents are as follows:(1)Determination and measurement of characterization parameters.The topological structure and the geometric structure of the model were analyzed to determine the characterization parameters needed to construct the potato tuber-root model.Three varieties of early white,Dutch fifteen and rich gold were selected,and 50 samples were selected for each variety to be able to count the number of roots.The excavation method is used to evaluate the characterization parameters of various rhizomes,and the shape and size of the tubers are measured by machine vision.(2)Statistical analysis and establishment of model parameter database.The spice software was used to analyze the parameters obtained from the field measurements,and the distribution rules of each characteristic parameter were found: the distribution function was established for the parameters with typical distribution characteristics;the probability distribution function was established according to the statistical results for the parameters without typical distribution characteristics.Finally,all the functions are summarized to establish a potato tuber-root model parameter table.(3)Model designs.Design data structure,containing the model's overall data structure,various rhizome organizational structures and single root data structures.Design the root modeling method,understanding the acquisition of the starting node,the acquisition of the root node and the simulation of the root axis.Visualization of various types of rhizomes ofpotato based on the morphological structure of numerous rhizomes: visualization of underground stems,seed roots,roots and stolons by means of round table splicing;visualization of tubers using elliptic functions;seedlings using semi-elliptic functions Visualization.The output parameters of the design model were calculated,including root depth,tuber distribution volume,root volume and root surface area.(4)Instance reconstruction and model checking.Based on MATLAB object-oriented technology,a simple potato tuber-root model building system was designed,including the structural design,process design and interface design of each stem.The tuber-root model of three varieties of potato was properly the authenticity of the seed root,alfalfa root and stolon model were tested.The 1:1 relationship between the simulated root value and the observed value of each root was linear.Good fits;RMSE values for each parameter are less than 20.The above results suggest that the potato tuber-root model constructed based on the model characterization parameters has good authenticity and reliability.In this paper,the structural characteristics of potato tuber-root model are analyzed,and a reconstruction algorithm is designed.The experimental results show that the model is real and reliable.The model can be used to simulate the interaction between excavation components and soil-tuber-root aggregates.It provides a theoretical basis for the design of the potato digging shovel and provides a reference for the construction of root models of fresh tuber crops.