National Aerospace Laboratories

About: National Aerospace Laboratories is a facility organization based out in Bengaluru, India. It is known for research contribution in the topics: Coating & Corrosion. The organization has 1838 authors who have published 2349 publications receiving 36888 citations.

Adaptive Nonlinear Neural Controller for Aircraft Under Actuator Failures

Abstract: This paper presents an adaptive backstepping neural controller design for aircraft under control surface failures. The control scheme uses radial basis function neural networks in an adaptive backstepping architecture with a full state measurement for trajectory following.13; The requirement for stability is separated from the network-learning part. This allows us to use any function approximation scheme (including neural networks) for learning. For the radial basis function neural networks, a learning scheme in which the network starts with no eurons and adds new neurons based on the trajectory error is developed. Stable tuning rules are derived for the update of the centers, widths, and weights of the radial basis function neural networks. Using Lyapunov's theory, a proof of stability in the ultimate bounded sense is presented for the resulting controller. The fault-tolerant controller design is illustrated for an unstable high performance aircraft in the terminal-landing phase subjected to multiple control surface failures of hard over type and severe winds. The design uses the full 6-degree-of-freedom nonlinear aircraft model, and the simulation studies show that the above controller is able to successfully stabilize and land the aircraft within tight touchdown dispersions.

Insights from a Pan India Sero-Epidemiological survey (Phenome-India Cohort) for SARS-CoV2.

Abstract: To understand the spread of SARS-CoV2, in August and September 2020, the Council of Scientific and Industrial Research (India) conducted a serosurvey across its constituent laboratories and centers across India. Of 10,427 volunteers, 1058 (10.14%) tested positive for SARS-CoV2 anti-nucleocapsid (anti-NC) antibodies, 95% of which had surrogate neutralization activity. Three-fourth of these recalled no symptoms. Repeat serology tests at 3 (n = 607) and 6 (n = 175) months showed stable anti-NC antibodies but declining neutralization activity. Local seropositivity was higher in densely populated cities and was inversely correlated with a 30-day change in regional test positivity rates (TPRs). Regional seropositivity above 10% was associated with declining TPR. Personal factors associated with higher odds of seropositivity were high-exposure work (odds ratio, 95% confidence interval, p value: 2.23, 1.92-2.59, <0.0001), use of public transport (1.79, 1.43-2.24, <0.0001), not smoking (1.52, 1.16-1.99, 0.0257), non-vegetarian diet (1.67, 1.41-1.99, <0.0001), and B blood group (1.36, 1.15-1.61, 0.001).