A system has been developed to interactively assemble modular and reconfigurable robotic systems in a computer animation environment. The modular robot is based on a set of one, two and three degree of freedom joint modules and generic links. These modules may be assembled into a large class of robotic systems that include serial, parallel, mobile and hybrid configurations. A model of the configured robotic system is immediately available for use in a wide variety of robotics
research areas, including: obstacle avoidance, redundant inverse kinematics, dynamic simulations, mobile platforms and world model databases.

INTRODUCTION

Computer animation provides a means of viewing robot motion to aid in human perception and decision making for both design and operation. Current applications of computer animation to robotics have focused on the simulation and programming of existing robots. The most common uses are workcell design, offline programming and the promotion of research programs. Since robots are usually purchased in their final configuration, there has been little demand for computer applications that aid in the design of the robot itself. The development of a modular reconfigurable robotic architecture presents an excellent opportunity to apply computer animation to the early stages of the robot design.
Interactive software packages that generate computer animations have found wide acceptance for programming and simulating industrial robots. Animated workcell design involves graphically placing the robot in its environment, also called the workcell. Machines, tools, parts and any other objects that the robot will interact with are also placed in the workcell. Computer animation is then used to visually simulate these interactions as the robot performs its task. Offline programming uses animation to replace the actual robot while programming the robot's motion and its interactions with its environment.

Current robots are purchased in their final configuration from the robot manufacturer. These robots are typically designed to perform a specific class of tasks, and if the application changes significantly the robot is rendered obsolete. The development of a generalised modular robotic architecture using a set of one, two and three degree of freedom joint modules and generic links greatly reduces the threat of obsolescence to the robotic system. A modular architecture also represents an excellent opportunity to use interactive computer animation in the development of robot technology through research enhanced by the use of three dimensional computer animation as a visualisation tool. Available graphics workstations can produce very smooth animations of a robot manipulator moving in a complex environment. Dedicated graphics hardware performs the calculations necessary to display solid-surface models on the computer screen.
The images can be displayed in colour, three dimensions, perspective and with hidden surfaces removed, resulting in very realistic animations. The main drawback to using these graphics workstations is that writing the programs for computer animation is complex and quite time consuming, often requiring thousands of lines of code to produce a single animation. The difficulty and significant time investment in writing the computer animation code has led to the development of application programs that aid in the production of computer animations on graphics workstations.