Research And Implementation On The Generalized Svstem For Precision Farm

The precision agriculture based on IoT can realize the elaborate management of agricultural production,save investment,gain economic and environmental benefits,is an important development direction of agricultural modernization.The present system is various,in the process of agricultural modernization,do not have a unified standard,somewhat higher cost of development and application,all of those hindered the development of the IoT of agriculture. So how to develop a generalized framework or specification for agricultural IoT and design devices of IoT that low cost and high reliability is particularly important.The paper designs and implements a generalized system which is suitable for farm environment by proposing a system design model,optimizing the access control method of RS485 bus and the group control method of ZigBee network and developing the generalized equipments.This paper has mainly completed the work listed below:1.According to characteristics of agricultural IoT’s generalized system,this paper proposes the "end-to-end" system design model based on the architecture reference model of IoT to realize the patition of the generalized system.2.Proposing three bus access control methods containing the active and the passive to solve the problems of concurrent blocking response and response delays in fault condition when accessing bus stations in order.This helps to improve the response rate of bus under the nomal condition and fault condition.3.Proposing a group control method of ZigBee network based on dynamic multicast to improve the poor efficiency when ZigBee is requested to operate by a number of commands at the same time.This helps to improve the response rate of ZigBee network when encounting to the concurrent operation.4.According to the structure of the generalized system of precision farm,this paper designs the devices of systerm which including the middleware of gateway and low-power ZigBee devices.These works provide the interface for the remote application,the platform for the local management and the reliable ZigBee devices. After building the system, this paper evaluates the targets and checks functions through black box testing.By test verification,the access control method based on the modified CSMA/CA of RS485 optimizes the response rate and the group control method based on dynamic multicast optimizes the response rate of ZigBee network.The system makes regional management independent,the IoT device platform is universe for kinds of devices,and the system capacity is extensible. The experimental results draw the conclusion that the generalized system designed by this paper meet design targets.