Research On Intelligent Agricultural Vehicle Control System Framework And Fault Tolerant Control Based On CAN Bus

Intelligent agricultural vehicle equipment represents advanced agricultural productivity.It is the material basis for increasing production efficiency,transforming development methods,and enhancing comprehensive agricultural production capacity.It is also the focus of technological competition in the international agricultural equipment industry.For intelligent agricultural vehicles,their intelligence is affected by the underlying communications,hardware architecture,software architecture and algorithms.The underlying communication is the basis for achieving intelligence.The hardware is the support for the realization of intelligence.The software is the expression of intelligence.The algorithm is the core of intelligence.In order to narrow the gap with foreign smart agricultural vehicle,this thesis has studied these issues.(1)Study CAN bus topology optimization and protocol formulation and encryption.Aiming at the negative correlation between the upper limit of the communication speed and the length of the bus,the topology model of the network node is established.The practical problem is abstracted as the minimum spanning tree model.The PRIM algorithm is used to solve the optimal path.Based on the established topology,the CAN bus communication protocol was developed based on factors such as data importance,ease of transmission,and sensor physical parameters.Comprehensively consider real-time,hardware requirements and attack difficulty and other practical problems to measure various encryption algorithms,use XXTEA algorithm to encrypt transmission data,and verify the node topology optimization and real-time data encryption.(2)Design agricultural vehicle communication topology and software architecture.The intelligent agricultural vehicle control platform sets up a distributed hardware structure model and an experimental platform for intelligent agricultural vehicles based on the differences in performance requirements of different sensors.And on this basis,from the actual demand for intelligent agricultural vehicles,write a specific design program for distributed software.By abstracting the underlying sensor driver,communication protocol formulation,control,and decision-making issues in different levels and perspectives,each sensor-driven design,communication design,control and decision design are decomposed and modularized to solve the problem.The hardware platform and software have been experimentally verified.(3)Research on lidar-based path planning and path-tracking under fault tolerance.Considering that the application scenario is a standardized farm with standard line spacing and plant spacing,multi-line laser lidar is proposed for path planning and navigation.The effect of the grid filtering parameters on the filtering is experimentally analyzed to determine the filtering threshold and the number of grids.The neighborhood parameter model is designed based on the physical parameters of the lidar.On this basis,the influence of neighboring parameters on clustering clusters was experimentally analyzed to determine the neighborhood parameters of density clustering.The DBSCAN algorithm of variable neighborhood parameters is designed to perform obstacle clustering.Hough transform and optimal square approximation are used to carry out straight line detection and fitting of the cluster to plan the path.Considering the design of fault-tolerant control strategy when the GPS/INS positioning signal is lost,the lidar is used to re-plan the path and the possibility of lidar navigation is verified through experiments.