LQG Control for Dynamic Positioning of Floating Caissons Based on the Kalman Filter.

This paper presents the application of an linear quadratic gaussian (LQG) control strategy for concrete caisson deployment for marine structures. Currently these maneuvers are carried out manually with the risk that this entails. Control systems for these operations with classical regulators have begun to be implemented. They try to reduce risks, but they still need to be optimized due to the complexity of the dynamics involved during the sinking process and the contact with the sea bed. A linear approximation of the dynamic model of the caisson is obtained and an LQG control strategy is implemented based on the Kalman filter (KF). The results of the proposed LQG control strategy are compared to the ones given by a classic controller. It is noted that the proposed system is positioned with greater precision and accuracy, as shown in the different simulations and in the Monte Carlo study. Furthermore, the control efforts are less than with classical regulators. For all the reasons cited above, it is concluded that there is a clear improvement in performance with the control system proposed.

Feasibility of an Exoskeleton Armrest to Improve Ergonomics during Endoscopic Sinus and Skull Base Surgery.

OBJECTIVE: The main objective of this study was to develop and evaluate the feasibility and effectiveness of a novel exoskeleton system designed to provide ergonomic assistance to surgeons while preserving or improving the quality of endoscopic sinus and skull base surgical procedures. METHODS: To evaluate the functionality and ergonomic characteristics of the device, five experiments were conducted in different and increasingly realistic scenarios: silicone model of the nasal cavity, freshly frozen cadavers and finally in a real surgery. Each volunteer's task was recorded and timed. The National Aeronautics and Space Administration Task Load Index (NASA-TLX) rating scale was used to estimate the surgeons' workload while performing the tasks. RESULTS: Twenty-five volunteers took part in the experiments. Volunteers perceived more comfort and less fatigue and pain when using the armrest than when not using the device (3.3, SD 1.75 vs. 5.9 SD 1.49; p = 0.02). Participants found the device intuitive, comfortable, and improving accuracy and stability with endoscope use. CONCLUSION: A new system that provides ergonomic assistance to surgeons was tested in simulation surgery with acceptable usability. Initial results in terms of pain and fatigue reduction and efficiency were excellent, justifying further research into this technology. LEVEL OF EVIDENCE: NA Laryngoscope, 134:79-86, 2024.