Another Component Based Programming Framework for Robotics

Developing software for controlling robotic systems is costly due to the complexity inherent in these systems. There is a need for tools that permit a reduction in the programming effort, aiming at the generation of modular and robust applications, and promoting software reuse. The techniques which are of common use today in other areas are not adequate to deal with the complexity associated with these systems [1]. This document presents CoolBOT, a component oriented framework for programming robotic systems, based on a port automata model [2] that fosters controllability and observability of software components. CoolBOT [3] [4] is a C++ component-oriented framework for programming robotic systems that allows designing systems in terms of composition and integration of software components. Each software component [5] is an independent execution unit which provides a given functionality, hidden behind an external interface specifying clearly which data it needs and which data it produces. Components, once defined and built, may be instantiated, integrated and used as many times as needed in other systems. In CoolBOT, components are modelled as Port Automata [2]. This concept establishes a clear distinction between the internal functionality of an active entity, an automaton, and its external interface, sets of input and output ports. Fig. 1 displays the external view of a component where the component itself is represented by a circle, input ports, ii, by the arrows oriented towards the circle, and output ports, oi, by arrows oriented outwards. Fig. 2 depicts an example of the internal view of a component, concretely the automaton that models it, where circles are states of the automaton, and arrows, transitions between states. Transitions are triggered by events, ei, caused either by incoming data through an input port, or by an internal condition, or by a combination of both. Double circles indicate automaton final states. CoolBOT components interact and inter communicate each other by means of port connections established among their input and output ports. Data are transmitted through port connections in discrete