Stabilizing hybrid switched motion control systems with an on-line trajectory generator

Abstract

This paper suggests the idea of a universal method for stabilizing discrete-time hybrid switched-control systems of robot manipulators. The core of this idea is based on an on-line trajectory generation algorithm that is able to generate continuous command variables from any arbitrary state of motion. We define a measurable criterion to on-line detect an instability or a potential instability of the plant, and right after this criterion is fulfilled, we switch to the on-line trajectory generator that acts as an open-loop pose control submodule in the switched-system. The on-line trajectory generation algorithm guides the system under consideration of kinematic motion constraints to a desired target state of motion that can be specified beforehand (e.g., zero-velocity in a pre-defined position). Systems with one and more degrees of freedom are regarded in this paper; finally, real-world experimental results achieved with a six-joint industrial manipulator are presented in order to demonstrate the potential and the high practical relevance of this concept.