Virtual Environments

Contact: Frank van der Stappen

Training systems for planning and mastering of delicate maneuvers or complex manipulation tasks will only be successful if their users have the impression that they are fully immersed in the virtual environment. The response of the system to the user's actions should therefore be immediate as well as physically realistic, which are two conflicting objectives.

Navigation (or motion) and interaction (often in the form of manipulation) are key issues in virtual environments. We concentrate on planning and simulation of motion and manipulation in complex environments. Examples are power plants and oil platforms where navigation is rendered difficult by huge numbers of often cluttered obstacles, and in medical applications such as minimally-invasive surgery where the situation is further complicated by the fact that the environment exhibits complex physical behavior such as deformation. Motion planning and collision detection techniques are necessary to plan and simulate these motions.

Motion is often not a goal in itself but a means of reaching a target area where a manipulation task is to be performed, such as the assembly of a spare part in a virtual factory or the removal of a tissue sample in virtual minimally-invasive surgery. For realistic simulation of these tasks we apply knowledge of techniques from robotics such as kinematics and the mechanics of manipulation. Manipulation regularly affects the geometry of an object. These changes in the geometry present interesting problems when combined with sophisticated models of physical behavior.

The research in the group focusses on the following topics:

Motion Planning in Virtual Environments
In virtual environments motion plays an important role. For example, in maintenance operations in factories we want to use the CAD models to plan the removal of malfunctioning parts, in large scale computer simulations there are computer controlled entities whose motion needs to be planned, and in games the motions of (large groups of) opponents must be determined. Such motions need to be effective and natural to enhance the feeling of immersion of the user/student/player. We study efficient algorithms to compute such motions.

Robotic Manipulation
Computer-supported design of industrial part handling processes can lead to a substantial cost reduction in automated manufacturing. We study efficient algorithms for planning low-cost and robust solutions (which are based on simple hardware elements performing simple physical action) to common part handling tasks such as part feeding and singulation, grasping or fixturing, and assembly and disassembly. We require our algorithms to be complete: they must find a solution whenever one exists.
We have also studied manipulation in the context of surgery simulation. In surgery simulation, physical actions such as cutting affect the geometry of the object under consideration. This poses challenges when combined with a need for realistic deformation.

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