Optimal Reconstruction of Flight Simulator Motion Cues Using Extended Kalman Filtering

For evaluation of simulator motion and motion platform dynamics, the motion cues generated in flight simulators need to be measured. For the SIMONA Research Simulator at TU Delft, the availability of redundant kinematic motion sensors i.e. an Inertial Measurement Unit and sensors that measure the lengths of the motion system actuators was expected to allow for optimal estimation of the flight simulator motion state using an Extended Kalman Filter. As a starting point, this sensor fusion problem was evaluated for only symmetrical simulator motion, omitting the additional asymmetrical motion states. The highly nonlinear relation between the extension of the motion base actuators and simulator position and orientation was found to require the application of an Iterative Extended Kalman Filter to ensure adequate filter convergence. Using this iterative filter, optimal estimates of the symmetrical simulator state and the IMU biases could be obtained from the two sets of redundant kinematic observations

Impact of phenylephrine administration on cerebral tissue oxygen saturation and blood volume is modulated by carbon dioxide in anaesthetized patients †

BACKGROUND: Multiple studies have shown that cerebral tissue oxygen saturation ([Image: see text]) is decreased after phenylephrine treatment. We hypothesized that the negative impact of phenylephrine administration on [Image: see text] is affected by arterial blood carbon dioxide partial pressure ([Image: see text]) because CO(2) is a powerful modulator of cerebrovascular tone. METHODS: In 14 anaesthetized healthy patients, i.v. phenylephrine bolus was administered to increase the mean arterial pressure ∼20–30% during hypocapnia, normocapnia, and hypercapnia. [Image: see text] and cerebral blood volume (CBV) were measured using frequency domain near-infrared spectroscopy, a quantitative technology. Data collection occurred before and after each treatment. RESULTS: Phenylephrine caused a significant decrease in [Image: see text] during hypocapnia [[Image: see text]=−3.4 (1.5)%, P<0.001], normocapnia [[Image: see text]=−2.4 (1.5)%, P<0.001], and hypercapnia [[Image: see text]=−1.4 (1.5)%, P<0.01]. Decreases in [Image: see text] were significantly different between hypocapnia, normocapnia, and hypercapnia (P<0.001). Phenylephrine also caused a significant decrease in CBV during hypocapnia (P<0.01), but not during normocapnia or hypercapnia. CONCLUSION: The negative impact of phenylephrine treatment on [Image: see text] and CBV is intensified during hypocapnia while blunted during hypercapnia