Robust autopilot design for landing a large civil aircraft in crosswind

A comprehensive autolanding design for a representative model of a twin-engined commercial aircraft is presented in this paper. To facilitate the design task and minimize control law switching, a cascaded control structure is selected which resembles integrator chains. Classical loopshaping and robust control techniques are used to design the individual control loops. The emphasis is on providing a complete and comprehensive qualitative design strategy. The control system’s ability to safely land the aircraft despite strong crosswind in a variety of possible scenarios is demonstrated in an industry-grade verification campaign. Nonlinear Monte Carlo simulations of the airliner model are used to assess the risk of unsafe landing conditions and provide insight into the performance characteristics and limitations of the proposed control system

Partial Pole Placement using Static Output Feedback

For many dynamical systems it is required to specifically shift individual poles, especially when these poles are lightly damped or even unstable. To achieve that, a preferably large number of effectors and measurements are installed leading to multivariable control problems. In this paper, a novel control approach is presented for placing either a single pole or a conjugate complex pole pair at a predefined location using rank-one static output feedback. Rank-one feedback can be interpreted as blending inputs and outputs to define a single input and single output loop with a desirable root locus along which the pole is moved. The corresponding controller synthesis is reduced to an unconstrained optimization problem in a single variable that aims at minimizing the feedback gain. Although the approach is derived for a single pole or conjugate complex pole pair, it is easily extended to multiple poles. To this end, a repeated design and superposition of rank-one feedback gains is proposed. It is further shown how residual system dynamics as well as subsequently designed gains can be efficiently decoupled from each other in order to avoid undesired interactions and spillover effects. The effectiveness of the proposed control approach is demonstrated by means of a numerical example

Impact of Spinal Instrumentation on Neurological Outcome in Patients with Intermediate Spinal Instability Neoplastic Score (SINS)

Background: Adequate assessment of spinal instability using the spinal instability neoplastic score (SINS) frequently guides surgical therapy in spinal epidural osseous metastases and subsequently influences neurological outcome. However, how to surgically manage ‘impending instability’ at SINS 7–12 most appropriately remains uncertain. This study aimed to evaluate the necessity of spinal instrumentation in patients with SINS 7–12 with regards to neurological outcome. Methods: We screened 683 patients with spinal epidural metastases treated at our interdisciplinary spine center. The preoperative SINS was assessed to determine spinal instability and neurological status was defined using the Frankel score. Patients were dichotomized according to being treated by instrumentation surgery and neurological outcomes were compared. Additionally, a subgroup analysis of groups with SINS of 7–9 and 10–12 was performed. Results: Of 331 patients with a SINS of 7–12, 76.1% underwent spinal instrumentation. Neurological outcome did not differ significantly between instrumented and non-instrumented patients (p = 0.612). Spinal instrumentation was performed more frequently in SINS 10–12 than in SINS 7–9 (p < 0.001). The subgroup analysis showed no significant differences in neurological outcome between instrumented and non-instrumented patients in either SINS 7–9 (p = 0.278) or SINS 10–12 (p = 0.577). Complications occurred more frequently in instrumented than in non-instrumented patients (p = 0.016). Conclusions: Our data suggest that a SINS of 7–12 alone might not warrant the increased surgical risks of additional spinal instrumentation

Role of Decompressive Surgery in Neurologically Intact Patients with Low to Intermediate Intraspinal Metastatic Tumor Burden

Background: Surgical decompression (SD) followed by radiotherapy (RT) is superior to RT alone in patients with metastatic spinal disease with epidural spinal cord compression (ESCC) and neurological deficit. For patients without neurological deficit and low- to intermediate-grade intraspinal tumor burden, data on whether SD is beneficial are scarce. This study aims to investigate the neurological outcome of patients without neurological deficit, with a low- to intermediate-ESCC, who were treated with or without SD. Methods: This single-center, multidepartment retrospective analysis includes patients treated for spinal epidural metastases from 2011 to 2021. Neurological status was assessed by Frankel grade, and intraspinal tumor burden was categorized according to the ESCC scale. Spinal instrumentation surgery was only considered as SD if targeted decompression was performed. Results: ESCC scale was determined in 519 patients. Of these, 190 (36.6%) presented with no neurological deficit and a low- to intermediate-grade ESCC (1b, 1c, or 2). Of these, 147 (77.4% were treated with decompression and 43 (22.65%) without. At last follow-up, there was no difference in neurological outcome between the two groups. Conclusions: Indication for decompressive surgery in neurologically intact patients with low-grade ESCC needs to be set cautiously. So far, it is unclear which patients benefit from additional decompressive surgery, warranting further prospective, randomized trials for this significant cohort of patients

GNU Radio

GNU Radio is a free & open-source software development toolkit that provides signal processing blocks to implement software radios. It can be used with readily-available, low-cost external RF hardware to create software-defined radios, or without hardware in a simulation-like environment. It is widely used in hobbyist, academic, and commercial environments to support both wireless communications research and real-world radio systems