OPEN EMBEDDED CONTROL

Embedded control devices today usually allow parameter changes, and po ssibly activation of different pre-implemented algorithms. Full reprog ramming using the complete source code is not allowed for safety, effi ciency, and proprietary reasons. For these reasons, embedded regulator s are quite rigid and closed concerning the control structure. In seve ral applications, like industrial robots, there is a need to tailor th e low level control to meet specific application demands. In order to meet the efficiency and safety demands, a way of building more generic and open regulators has been developed. The key idea is to use pieces of compiled executable code as functional operators, which in the sim plest case may appear as ordinary control parameters. In an object ori ented framework, this means that new methods can be added to controlle r objects after implementation of the basic control, even at run-time. The implementation was carried out in industrially well accepted lang uages such as C and C++. The dynamic binding at run-time differs from ordinary dynamic linking in that only a subset of the symbols can be u sed. This subset is defined by the fixed part of the system. The safet y demands can therefore still be fulfilled. Encouraged by results from fully implemented test cases, we believe that extensive use of this c oncept will admit more open, still efficient, embedded systems.