Robots in Virtual Manufacturing

In this study sponsored by the University of Michigan's Program in Manufacturing (PIM), we investigated the use of VRML, the Virtual Reality Modeling Language on the World Wide Web, for the modeling of robot operations. Functional robots can be modeled using VRML's scripting capability. This paves the way for a future Web environment where robots (or other functional machinery) can be downloaded from the supplier's Web site and placed in the virtual model of a factory. Ultimately, the downloaded equipment would be fully functional and would allow for the simulation of a production process before any hardware is being bought and installed.

Robot Libraries on the Web

Libraries for the selection of industrial robots are already available on the Web. Some of them provide three-dimensional models of these robots. At Robot Simulations Ltd. we found under "robot library" a virtual library of 174 standard robots. For each robot, a VRML model containing the robot's geometry is provided. The models are passive (not functional), but one can envision intelligent robot models on a supplier's Web site that can be downloaded and fed with a robot control program developed for a specific task by the user.

Sample robots from the virtual robot library

Robot Programming

To illustrate the principle of robot programming in VRML, we downloaded the MITSUBISHI MOVEMASTER EX from Robot Simulations Ltd. and expanded the VRML file to include control menus and a complete animation. This changed the initially passive geometry into a functional robot.

Screen shot: control menus of functional VRML robot
Web size (15K) - Screen size (23K)

Each pair of the color-coded "+" and "-" buttons operates the individual robot link of the respective color. The "Animate" button executes a predefined robot control program. In the future, we would like to control the robot by an externally provided robot control program.

Load the functional VRML 2.0 robot (8K) and operate the MITSUBISHI MOVEMASTER EX

Simulation of Production Process

In the next step, we made copies of the robot, programmed each robot individually, and placed them into a simplified VRML factory. The resulting simulation with animated robots allows to check for layout efficiency, correctness of robot programming, robot reach, clearances, interferences, collision events, and other aspects.

Screen shot of simplified VRML factory with robots at work
Web size (30K) - Screen size (41K) - Max size (42K)

Load the animated VRML 2.0 factory (42K) and use "Next Viewpoint" from the browser control panel to move through the scene

Welding Robot

Another functional robot illustrates the execution of a spot welding task. We adopted this robot from NIST (National Institute of Standards and Technology), modified the model, and placed it in our small production environment. After downloading the VRML file (below), click on the robot's gray pedestal to start the welding operation. Clicking on any of the robot's links will demonstrate its movement. Turning the browser's headlight off causes the scene to be illuminated only by the welding sparks.

Spot welding robot
Web size (59K)
Load the VRML 2.0 spot welding robot (60K), click on the robot's base to start operation

The Towers of Hanoi

Robots are flexible machines that can be used for a variety of tasks. Here is a specially designed VRML robot that will assist you in solving the classical brain puzzle "Towers of Hanoi" based on an ancient legend from India.

Objective and Rules: Instructions:

Web size (10K) - Screen size (8K)
Play the "Towers of Hanoi" in VRML 2.0 (8K)

Credits: Steffen Heise searched the robot library, programmed the MITSUBISHI MOVEMASTER EX, simulated the production process, and created the "Towers of Hanoi" in VRML. Diganta Saha contributed to the welding robot. The Program in Manufacturing (PIM) supported this study through an educational grant.

Last Update: December 7, 2002, kpb
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