Model-based constrained motion. a. Modeling, specification and control

Model-based constrained motion is presented as an extension to Mason´s ´task frame´ or ´compliance frame´ formalism (1981). The basic model building blocks are the constraint´s ´features´. Their explicit use of symbolical, geometrical and analytical models of the motion constraints increases the flexibility in specification and control. This results in a larger range of possible applications in uncertain environments, and better interfaces, not only to the human user, but also to the off-line task planner and the online task monitor and executor. This text describes the ideas underlying the ´feature frame´ approach, as well as the extra programming and design efforts needed to realize the increased flexibility. A simple task is given as an example application: ´incompatible seam tracking´. This task cannot be specified, nor executed, by means of the classical task frame approach.<>