Open configurable control system for precision farming

The goal of Agrix project is to develop a prototype of an open, generic and configurable automation platform for agricultural machinery. A typical configuration consists of a tractor and one or several implements. The main purpose of realizing the fast-prototype of the control system in 2003 was to get acquainted with the problems occurring in working with agricultural machines. Experiences from the fast-prototype are reported in this paper. The agricultural implement selected for the fast-prototype was a combined seed and fertilizer drill. The original hydraulic system was replaced with a new electro-hydraulic valve block. The tractor was equipped with ISOBUS (ISO 11783) compatible electronic control unit. A commercial CAN-controller with a high-power digital and analog I/O interface was used as the implement electronic control unit. The architecture of Agrix fast-prototype was designed according to ISOBUS standard. In industrial automation, standard inexpensive PCs are used as Human Machine Interface (HMI). Accordingly, it was tested if a standard PDA or handheld could be used as HMI or user terminal for the implement. The Agrix fast-prototype was finally tested in real drilling of wheat. The ISOBUS standard is very important as an open communication standard for agricultural machines. However, it does not have any features to support configurability. The biggest problems occurred with the PDA. Its display is quite small to be used as HMI in a moving vehicle. The inexpensive external keyboard was a bit too vague for its purpose. The processing power of the PDA was quite limited for this kind of use and real-time problems emerged in some situations.