Matti Öhman

Simultaneous Localization and Mapping for Forest Harvesters

A real-time SLAM (simultaneous localization and mapping) approach to harvester localization and tree map generation in forest environments is presented in this paper. The method combines 2D laser localization and mapping with GPS information to form global tree maps. Building an incremental map while also using it for localization is the only way a mobile robot can navigate in large outdoor environments. Until recently SLAM has only been confined to small-scale, mostly indoor, environments. We try to addresses the issues of scale for practical implementations of SLAM in extensive outdoor environments. Presented algorithms are tested in real outdoor environments using an all-terrain vehicle equipped with the navigation sensors and a DGPS receiver.

Tree Measurement and Simultaneous Localization and Mapping System for Forest Harvesters

For the last decades, measurement and automation systems in Nordic cut-to-length forestry machines have evolved gradually. These heavy duty machines are lighter, faster and more accurate than ever before but the basic technologies and operation have remained the same. In many respects, their current automation systems have reached their limits. The Forestrix project studies how advances in mobile robotics could be applied in the field of forestry machine automation. Machine vision systems and scanning laser range finders have established themselves as standard equipment in mobile robotics. With the new sensor and computing technologies it is possible to get information about the surrounding forest, such as tree diameters, positions and stand density. This information can be used on-line in operator’s decision support system, or off-line in a forest asset management system. This paper describes the prototype measurement platform and the software algorithms developed in the Forestrix project. Results from tests with an all terrain vehicle are also presented.

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.

ISO 11783 –STANDARD AND ITS IMPLEMENTATION

Abstract For years electronic control has been used to enhance the performance of various components in agricultural machinery e.g. engine, transmission and implement functions. Yet networking these components has potential to significantly improve the performance and modularity of the total system. The ISO 11783 standard specifies the communication between a tractor and an implement. Standardized communication is needed to ensure compatibility and interoperability of components from different manufacturers. In the Agrix Project the automation of agricultural implements is researched. The Agrix Basic Prototype is based on the ISO 11783 standard. The ISO 11783 compatible commercial tractor and virtual terminal are shortly reviewed and the realised implement controller, task controller and GPS-adapter are presented in this paper.

Remote Maintenance of Agricultural Machines

Abstract 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. Fault tolerance and remote maintenance over mobile networks are essential research topics due to short seasons for agricultural operations especially in Nordic countries. 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, some initial tests to realizethe mobile communication system and principles of remote maintenance are reported in this paper. The agricultural implement selected for the fastprototype was a combined seed and fertilizer drill. The tractor was equipped with ISOBUS compatible electronic control unit. A commercial CAN-controller with a highpower 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 (ISO 11783) standard.

XML Based Graphical User Interface Editor and Runtime Parser for ISO 11783 Machine Automation Systems

Abstract Graphical user interface design is a very visual process which requires graphical tools. Modern integrated development environments have text editors for writing code and graphical user interface editors for designing the user interface. In ISO 11783 systems this distinction between the program logic and the user interface elements is even more pronounced as the program is executed by the electronic control unit on the agricultural implement while the user interface is being loaded to the virtual terminal in the tractor cabin. The ISO 11783 standard defines a binary format for loading user interfaces to the virtual terminal. However, using XML format for manipulating and storing user interfaces has many advantages. XML files can be validated and parsed by standard tools and libraries. They are human readable which makes debugging relatively easy. XML files can also be extended to contain new information without breaking existing implementations. Most importantly, describing user interfaces as structured documents allows efficient reuse of composite user interface objects such as entire displays.