Controller Driven VRML Animation of the NIST Robotic Welding Cell

Abstract

Abstract Virtual objects in a web-based environment can be interfaced to and controlled by external real world controllers. A Virtual Reality Modeling Language (VRML) welding cell was created that models a robotic arc welding cell (the Automated Welding Manufacturing System project,) located at the National Institute of Standards and Technology (NIST). The VRML welding cell contains a model of a 7 degree-of-freedom robot, a welding table, torch and various fixtures and parts. The VRML robot is interfaced to, and can be controlled by, the real world robot controller. This is accomplished by a socket connection between the collaborator’s web browser and the real world controller. The current joint angles of the robot, which are stored in a world model buffer in the controller, are collected by a Java applet running on the web page. The applet updates the VRML model of the robot via the External Authoring Interface (EAI) of the VRML plug-in. Virtual welds, a series of VRML cylinders, are also dynamically created every 100 ms on the part based on the current robot position and colored according to the calculated weld quality of that section of weld obtained from the real world controller. This allows a collaborator to visually determine where a bad section of weld has occurred without being present in the physical welding lab.