SIMpact is a system currently under development at the Robotics Laboratory at Stanford University to accurately model and simulate the interactions between robots and their environments. The ability to preview the behavior of a robotic system in a "virtual" environment allows different mechanisms, configurations and controllers to be tested before being applied to a real physical system.

The simulator we have developed takes robot actuator control signals from the controllers, determines if contact or collision between objects in the system has occured, and returns simulated sensor information as feedback. If a collision occurs the simulator applies the necessary collision impulses, or contact forces at the contact points in order to prevent penetration. In an ideal system, a robot controller that is connected to physical robots can be re-connected to our dynamic simulator to view the interactions between the robots and their environment. This allows many different ideas to be tested efficiently, and cost effectively, without the dangers normally associated with debugging on a real system.

This work builds on previous work, in computer graphics, to physically model simple rigid bodies but extends it to correctly model, and efficiently compute the motion of multi-link robots.


Diego C. Ruspini,
Oussama Khatib,


Simulation of two puma560 robots crashing into each other MPEG (335K)

Simulation of a puma560 robot playing with dominos MPEG (1.6MB)

Lee, Paul, Diego Ruspini and Oussama Khatib, "Dynamic Simulation of Interactive Robotic Environment", International Conference on Robotics and Automation, San Diego, CA, May 1994, pp 1147-1152. available Postscript(3.3MB)
Ruspini, Diego and Oussama Khatib, "Collision/Contact Models for the Dynamic Simulation of Compex Environmnets", IEEE/RSJ International Conference on Intelligent Robots and Systems:IROS'97, September 1997, Genoble, France. available Postscript(1.8MB)


e-mailDiego C. Ruspini (