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The ongoing work in our laboratory for multimodal human-computer interaction is focused on the development of a system for virtual reality with haptic feedback based on light weight arm exoskeletons. The key features of this system are a high degree of immersion into the computer generated virtual environment and a large working volume. The high degree of immersion will be achieved by multimodal human-exoskeleton interaction based on haptic effects, audio and three dimensional visualization. The large working volume will be achieved by a lightweight wearable construction which can be carried on the back of the user.

System overview

In order to achieve this, a system is being developed which consists of the following three main modules:

A lightweight wearable exoskeleton for the human arm which will provide haptic feedback in a largescale virtual environment. The design of the mechanics will be non-grounded and supported by the users body.
A high-fidelity head-mounted display with very good stereoscopic properties to display the threedimensional environment and give the user a sense of depth.
An optical tracking system in order to track the users position.
A highend rendering system which calculates the 3D-Scene and forces caused by the interaction of the user with the virtual environment.

System overview

Figure 1: Diagram of the multimodal virtual reality system

3D Tracking

The position and orientation of the user in the real workspace is going to be tracked by a state of the art motion tracking system. This will allow access to a larger workspace in the virtual environment which is one of the most important properties common multimodal virtual reality systems nowadays still lack. In addition to this the orientation of the users head will be tracked by a 3DOF tracking device so that the users movements of the head will be translated to rotation of the viewports orientation displayed by the graphics server.

Software Design

The software design will follow a modular approach so that the different domains of the multimodal system can interact even though they run with different update rates. This is necessary because of the fact that the human's sense of touch interpretes forces only in a natural way if these are being presented by the system with an update rate of at least 1000Hz whereas the visual render module only requires an update rate of approx. 60Hz for a smooth 3D visual experience.

Research Topics

The inherent mechanical properties of the haptic feedback arm in conjunction with the key features of a virtual reality system with haptic feedback lead to the following three main research topics which will be covered in the project:

The first resarch field is the development of algorithms for appropriate combination of the three modalities audio, vision and haptics for reproducing different interaction effects.
The control of mechanical constructions with bad stiffness in haptic applications will be the second research topic.
The third research field will cover efficient algorithms for visualization, collision detection and force rendering in large three dimensional virtual environments.

System overview

3D Tracking

Software Design

Research Topics

Links to other projects