Research On Key Technologies On Farm Task Allocation For Multi-machine Cooperative Operation

The multi-machine coordination technology of agricultural machinery is a key link to improve the utilization efficiency of agricultural machinery and increase the large-scale production capacity of farm machinery.Task allocation is an important evaluation index for the cooperative operation of agricultural machinery group.How to reasonably allocate each task to a suitable agricultural machine before the operation of the agricultural machinery group,or to re-allocate the operation plan of the agricultural machinery when a new(emergency)task occurred,so as to maximize the benefits of the group is a problem that has plagued agricultural machinery cooperatives or farms for a long time.In this study,a systematic research on the above problems was carried out.Initially,according to the task allocation requirements,the acquisition of the two key basic parameters of the agricultural machinery turning radius solution method and the agricultural machinery field operation path planning method were carried out.Then,according to the actual operation requirements,the static task allocation method and dynamic task allocation method of the same kind of agricultural machinery multi-machine cooperative operation were studied.The specific research contents are as follows:1.Multi-machine cooperative architecture was designed.The agricultural machinery multi-machine coordination system structure and the agricultural machinery automatic driving technology system structure were proposed.The GNSS positioning technology and the fusion technology based on GNSS and inertial navigation were studied.Based on data and related content derived form the "Agricultural Mechanization Precision Operation Platform",a method for solving the shortest path in the field based on the Dijkstar algorithm was establishe.2.Automatic turning control method of agricultural machinery was studied.In order to solve the problem that the turning radius of the crawler tractor cannot be accurately controlled,the mathematical model of the turning radius of the hydraulic steering control crawler tractor was deeply analyzed and established.The turning radius control method of the crawler tractor was proposed based on the Gaussian mixture model.The results showed that,when the initial heading angle was 0° and the vehicle speed was 1.0m/s and 1.5m/s,the average navigation error was-0.62cm and 0.28cm,and the absolute value of the navigation error was 10.14cm and 8.10cm.The mean absolute values of navigation errors were 2.34 cm and 2.57 cm,respectively,and the root mean square errors of navigation were 3.77 cm and 3.99 cm,meet the actual field operation requirements.3.The field path planning method of agricultural machinery was carried out.Taking agricultural machinery turning radius as an important parameter,the agricultural machinery field operation process,agricultural machinery field turning method,and the turning path length of various turning methods were studied.The agricultural machinery operating path direction planning method was established according to the minimum number of turns,and the minimum number of paths was skipped according to the bow-shaped turn.The problem established a method for planning farm machinery field operations based on bow turning.Laid the foundation for the task allocation method of multi-machine cooperative operation.4.Static task allocation for multi-machine cooperation of the same kind of agricultural machinery was studied.The cost function of multi-machine cooperative operation was established.Based on the genetic algorithm,the two-stage coding method,grouping crossover operator and multiple mutation operators were designed to solve the problem.The multi-variation group genetic algorithm was established.The test results show that the cluster cost of multi-machine cooperative static task allocation based on the multi-variation group genetic algorithm was reduced by 35.88%?55.00%compared with the actual operation cost under different weights.This method can meet the requirements of task allocation in the actual multi-machine cooperative operation of agricultural machinery.5.Dynamic task allocation for multi-machine cooperation of the same kind of agricultural machinery was studied.In order to solve the problems of increased work time and the inability to complete certain work tasks caused by emergencies in the process of agricultural machinery operations,based on the characteristics of the interaction between agricultural machinery and the related processes of contract network protocol,a bulletin board-based dynamic task allocation was proposed.The contract network protocol was improved by selecting tenderers,setting the bidding threshold,task redistribution of the successful bidder,and the most costly agricultural machinery task exchange.The test results show that,at different task allocation times,the cost based on the improved contract network protocol was reduced by 30.20%?34.09%compared to the actual theoretical cost,which can meet the dynamic task allocation requirements of the same type of agricultural machinery cluster in agricultural production.