Development of robust communication algorithm between machine vision and boom sprayer for spot application via ISO 11783

Abstract

A communication algorithm to send data via the standard communication protocol for agricultural implements, ISO 11783, was developed and tested in this research work. The goal was to enable a universal method to integrate machine vision systems to sprayers so that sensor-based real-time spot spraying becomes possible in the future. The algorithm receives pest detection results from a machine vision and constructs messages compatible with ISO 11783 (also known as ISOBUS), which gets sent to the sprayer. This allows for simultaneous opening of different nozzles on the sprayer even when pests are detected by different cameras at different locations across the boom. The results on our spraying apparatus which consisted of 6 nozzles showed that correct spraying commands were sent to the nozzles 100% of the times for all possible 64 simultaneous nozzle opening/closing combinations. The algorithm was designed to construct CAN frames based on arithmetic rather than logic operations. Also, the increase of data load on the ISOBUS of the sprayer was limited to 5.2%. Moreover, no data loss between the machine vision system and the sprayer was observed even when the data frames were sent every 10 milliseconds. The electronic control unit (ECU) on which the algorithm was written has two interfaces, one communicates with the machine vision system using serial communication, and the other communicates with the sprayer using the ISOBUS. The universal serial communication protocol used in this development allows for immediate integration to the ECU which creates the messages according to the specifications of the nozzle control unit of the sprayer.

Keywords

• Machine vision
• Isobus
• Controller area network
• Boom sprayer
• Spot application