Principles of Robot Simulation and their Application in a PC-based Robot Simulation System

This paper addresses some fundamental topics which have to be regarded during the design, implementation and usage of graphical robot Simulation systems.After a short summary of robot Simulation system purposes, we derive the basic requirements, which have to be satisfied, in order to obtain a useful Simulation system. We show, that different modeling steps are necessary to build up an internal representation of a robot arm and the robot work cell, which can be used to simulate and visualize the execution of robot tasks. The main parts of such a model are the geometrical and the kinematical representation. Different geometrical representations and possible modeling techniques are presented. In addition, general considerations about the computation of the robot kinematics and its inverse, which plays an important role in off-line robot program development, are made. An affixment technique which is used to combine the kinematical and the geometrical model is introduced and the working principle is demonstrated with the help of a modeled example world.Finally we focus on some special aspects of robot Simulation such as the graphical visualization and the different interpretations of time within a Simulation system; in addition, we outline the main Software modules, which are more or less incorporated in each graphical robot Simulation system.Many of the discussed principles of graphical robot simulation are illustrated by means of a PC-based graphical robot simulation system. This system was designed and implemented at our institute and is currently used to teach students some principles of robotics within practical courses.