In the MotionLab we study the integration of cues from the visual, auditory, vestibular and somatosensory system. The center piece of the MotionLab is a hexapod Stewart platform (Cuesim) with six degrees of freedom. Mounted on the platform is a cabin with two interchangeable screens, a flat screen and a curved screen, both with a field of view of 86°×63°. The projector has a resolution of 1400×1050 with a refresh rate of 60 Hertz. Beneath the seat and foot plate are subwoofers which can be used to simulate high frequency vibrations in driving and flight simulators and mask the vibrations caused by the platform electric motors. The MotionLab was designed as a distributed system that is driven by multiple computers. Software control is based on an in-house development (xDevL) that can be used both with C++ and Virtools ™ programs.

The characteristics of the Stewart platform have been objectively measured with a standardized approach. It was found that the dynamic response of the platform is determined by the platform filters implemented by the manufacturer, the system time delay, and the noise characteristics of the actuators. These characteristics have been modeled and simulated on the SIMONA Research Simulator at Delft University of Technology. Experiments on the influence of these characteristics on human control behavior have shown that the limitations of the platform filters cause humans to rely predominantly on visual cues in a closed-loop target-following disturbance-rejection control task.

We have employed a large screen, half-cylindrical virtual reality projection system to study human perception since 1997. Studies in a variety of areas have been carried out, including spatial cognition and the perceptual control of action. In 2005, we made a number of fundamental improvements to the virtual reality system. Perhaps the most noticeable change is an alteration of the screen size and geometry. This includes extending the screen horizontally (from 180 to 230 degrees) and adding a floor screen and projector. It is important to note that the projection screen curves smoothly from the wall projection to the floor projection, resulting in an overall screen geometry that can be described as a quarter- sphere. Vertically, the screen subtends 125 degrees (25 degree of visual angle upwards and 100 degrees downwards from the normal observation position).

In 2011 the image generation and projection setup was significantly updated. The existing four JVC SX21 DILA projectors (1400x1050) and curved mirrors were replaced with six EYEVIS LED DLP projectors (1920x1200), thereby simplifying the projection setup and increasing the overall resolution. In order to compensate for the visual distortions caused by the curved projection screen, as well as to achieve soft-edge blending for seamless overlap areas, we have developed a flexible warping solution using the new warp and blend features of the NVIDIA Quadro chipsets. This solution gives us the flexibility of a hardware-based warping solution and the accuracy of a software-based warping. The necessary calibration data for the image warping and blending stages is generated by a new camera-based projector auto-calibration system (DOMEPROJECTION.COM), Image generation is handled by a new high-end render cluster consisting of six client image generation PCs and one master PC. To avoid tearing artifacts resulting from the multi-projector setup, the rendering computers use frame-synchronized graphics cards to synchronize the projected images.

In addition to improving the visual aspects of the system, we increased the quality, number, and type of input devices. Participants in the experiments can, for example, interact with the virtual environment via joysticks, a space mouse, steering wheels, a Go-Kart, or a virtual bicycle (VRBike). Most of the input devices offer the possibility of force-feedback. With the VRBike, for example, one can actively pedal and steer through the virtual environment, and the virtual inertia and incline will be reflected in the pedals' resistance.

The quarter-sphere projection setup is complimented by a back-projection setup, which has the advantage that participants do not create shadows on the screen. This setup consists of a single SXGA+ projector (Christie Mirage S+3K DLP) and a large, flat screen (2.2m wide by 2m high). The projector has a high contrast ration of 1500:1 and can be used for mono or active stereo projections. This space has four VICON® V-series cameras for motion tracking, which has been used in recent studies investigating the influence of motion-parallax and stereo cues for depth and size perception.
For stereo projection setup, the NVIDIA 3DVision Pro active shutter-glasses are used. These glasses use RF technology for synchronization and therefore can also be used in conjunction with the infrared-based VICON® tracking system. The glasses have been modified with markers for the optical tracking system and thus can be used for head tracking.

Heli-Lab is a fixed-based flight simulator that affords a large field of view (i.e., 105°x100°). It is equipped to measure explicit and implicit behavioral responses — respectively, control stick inputs as well as eye-tracking and physiological measures. Thus, we are able to study the relationship between a pilot's actions and his cognitive workload during flight maneuvers.

The core system is an open-source flight simulator (FlightGear, www.flightgear.org) that accepts control inputs that are processed by a designated aircraft model to compute the appropriate world position and orientation of a modelled aircraft. Subsequently, these values are used to render the corresponding display of the world scene as seen from the cockpit, via a computing cluster for 10 wide-screen monitors.

Our system is equipped to record implicit behavioral responses. A remote eyetracking system (2 stereo-heads, 60 Hz; Facelab, Seeing Machines, USA) monitors the pilot's line-of-sight in the world scene as well as gaze on the heads-down instrument panel. Physiological measurements of the pilot are also recorded in tandem using a 16-channel active electrode system (g.Tec Medical Engineering GmbH, Austria). This system can be used to monitor the pilot's galvanic skin response, heart-rate variability and electro-encephalographic signals.

There are two control systems for the flight simulator that both feature generic helicopter controls such as a cyclic stick, a collective stick, and pedals. One system is unactuated and serves as any common joystick, while the other system consists of motorized controls (Wittenstein AG, Germany). This actuated system can be configured to resemble a wide range of control system dynamics, and can provide haptic feedback cues to the pilot. These cues can be used to support the pilot’s situational awareness.

The image here shows a schematic overview of the system (left). The information received by the user (red) and his control as well as physiological responses (blue) constitute part of this closed-loop system. A photo of the simulator in use (right) shows a participant performing a closed-loop control task (i.e., landing approach) while gaze is measured in real-time (inset).