AN EXPERIMENT WITH REACTIVE DATA-FLOW TASKING IN ACTIVE ROBOT VISION

This paper presents an experiment with the synchronous approach to rea ctive systems programming, and particularly the Signal language, appli ed to a significant problem in robot vision: active visual reconstruct ion. This application consists of the specification of a system dealin g with various domains such as robot control, computer vision and tran sitions between different modes of control. It illustrates the adequac y in such domains of Signal, a data flow programming language and envi ronment. The programming environment features tools for formal specifi cation, analysis, consistency checking and code generation. Signal and its language-level extension for task preemption SignalGTi are used a t the different levels of the application: data-flow function for the camera motion control (visual servoing), reconstruction method (in par allel to visual servoing, involving the dynamical processes), and reco nstruction of complex scenes (with transitions between several robotic s tasks). The combination of these levels constitutes a hybrid behavio r with (sampled) continuous control and discrete transitions. These te chniques are validated experimentally by an implementation on a roboti c cell. (C) 1997 by John Wiley & Sons, Ltd.