Next Generation Task Controller for agricultural Machinery using OPC Unified architecture

Abstract

ISO 11783 is a communication protocol for tractors and implements. It specifies a network of control functions connected with a CAN bus. The task controller is a control function that is used to control implements based on planned tasks. Implements expose their structure to the task controller with Device Descriptor Object Pool XML files. The guidelines for modelling implements leave room for interpretation, which can lead to compatibility issues. The agricultural industry has decided that the physical layer of the future high-speed ISOBUS will use Ethernet, but the higher OSI layers are undecided. One Ethernet-compatible middleware to be considered is OPC UA, a platform-independent communication standard for systems and devices. It uses object-oriented information modelling techniques and allows users to define new information models based on the OPC UA base information model and its standardized extensions. In this article, an OPC UA information model was designed for data exchange between the task controller and implements, and its suitability for use in the high-speed Next-Generation ISO 11783 Task Controller was evaluated. Modelling rules for the information model were designed with a focus on modelling all types of implements that apply a product or products. OPC UA Implement Server and OPC UA Task Controller applications were developed to test the information model. The evaluation of these OPC UA applications showed that the OPC UA model (OPC UA for the Next Generation ISO 11783 Task Controller information model) presented is suitable for communication between the task controller and implements.