Research Of Wireless Communication Technology For Agricultural Multi-robot Systems

In the field of agricultural production, the disadvantage of a single robot to perform tasksis more and more obvious. Therefore, scholars have begun to carry out research foragricultural multi-robot system. Face of domestic research is scarce of the wirelesscommunication technology for multi-robot systems, to eventually built a wirelesscommunicate system for wheat combine harvester multi-robot system, we have done someresearch in the theory and practice of wireless communication technology. We analyzed themeaning and application of current wireless communications technology in agricultural robot,discussed communication conditions and channel characteristics of agricultural multi-robotsystems by the method of combining theoretical analysis, field testing and simulation. Basedon research of related communication protocol, we set up communication system, designedrelated wireless communications agreements and prepared the related software.The main research works and the results are as follows:(1) Depth analyzed the technical characteristics of WPAN, WLAN, WIMAX andWMAN and their application status in the field of agricultural robot, we proposed theapplication of wireless communication technology has four levels in the field of agriculturalrobots. We pointed out that the level of agricultural robotics applications of wirelesscommunication technology is far behind the level of wireless communication technologydevelopment itself, and that building high-performance WLAN should be the key to researchagricultural multi-robot systems at present.(2) Based on the characteristics of wheat multi-robot systems that the communicationconditions are relatively vague, we found a calculation formula for the effectivecommunication range by analyzing the different formations of multi-robot systems. Use ofchannel measurement and curve fitting method, the regression curve of percentage signalstrength and transmission rate on the distance has been established. The impact of the crop onthe wireless signal propagation has been explored by comparing the signal strength in thewheat fields, the ground and the air in three different cases.(3) By NS2wireless simulation, we created the regression curve of packet loss rate,delay and throughput parameters on the distance in wireless channel under the conditions ofmovement, and investigated the effect of speed on the wireless transmission quality. Abovework made the communication conditions and performance of agricultural multi-robot system clear and provided theoretical guidance for deploying agriculture multi-robot systems.(4) On the basis of in-depth research on WLAN transmission protocol, a multi-robot SoftAP communication structure has been established. Based on Socket Programming Principle,we designed protocols and session’s process, designed communications interface to leaderand follow harvesters, finally completed program debugging. Program debugging andcommissioning results show that the software can be a good two-way data transmission with acentral multi-robot system, and its characteristics suitable for wheat combine harvestermulti-robot systems.