Aerospace & Defense
Army ditches helicopters for new radical air assault planes
Fox News contributor Brett Velicovich joins'Fox & Friends First' to discuss Secretary's Hegseth's sweeping Army transformation, how Russia has responded to the U.S. minerals deal with Ukraine and the military bolstering drone technology. This is how the Army will island hop in the Pacific to fend off China. And by the way, Chinese President Xi Jinping has nothing like it. With a stunning announcement, the Army did more than ax 40 generals and open the door to AI. The Army bet its future on this radical aircraft, whose engines swivel to take off and land like a helicopter, or fly high and fast like an airplane.
Robot Talk Episode 119 โ Robotics for small manufacturers, with Will Kinghorn
Claire chatted to Will Kinghorn from Made Smarter about how to increase adoption of new tech by small manufacturers. Will Kinghorn is an automation and robotics specialist for the Made Smarter Adoption Programme in the UK. With a background as a chartered manufacturing engineer in the aerospace industry, Will has extensive experience in developing and implementing automation and robotic solutions. He now works with smaller manufacturing companies, assessing their needs, identifying suitable technologies, and guiding them through the adoption process. Last year he released a book called'Digital Transformation in Your Manufacturing Business โ A Made Smarter Guide'.
Surrogate-based optimization of system architectures subject to hidden constraints
Bussemaker, Jasper, Saves, Paul, Bartoli, Nathalie, Lefebvre, Thierry, Nagel, Bjรถrn
The exploration of novel architectures requires physics-based simulation due to a lack of prior experience to start from, which introduces two specific challenges for optimization algorithms: evaluations become more expensive (in time) and evaluations might fail. The former challenge is addressed by Surrogate-Based Optimization (SBO) algorithms, in particular Bayesian Optimization (BO) using Gaussian Process (GP) models. An overview is provided of how BO can deal with challenges specific to architecture optimization, such as design variable hierarchy and multiple objectives: specific measures include ensemble infills and a hierarchical sampling algorithm. Evaluations might fail due to non-convergence of underlying solvers or infeasible geometry in certain areas of the design space. Such failed evaluations, also known as hidden constraints, pose a particular challenge to SBO/BO, as the surrogate model cannot be trained on empty results. This work investigates various strategies for satisfying hidden constraints in BO algorithms. Three high-level strategies are identified: rejection of failed points from the training set, replacing failed points based on viable (non-failed) points, and predicting the failure region. Through investigations on a set of test problems including a jet engine architecture optimization problem, it is shown that best performance is achieved with a mixed-discrete GP to predict the Probability of Viability (PoV), and by ensuring selected infill points satisfy some minimum PoV threshold. This strategy is demonstrated by solving a jet engine architecture problem that features at 50% failure rate and could not previously be solved by a BO algorithm. The developed BO algorithm and used test problems are available in the open-source Python library SBArchOpt.
Block Toeplitz Sparse Precision Matrix Estimation for Large-Scale Interval-Valued Time Series Forecasting
Modeling and forecasting interval-valued time series (ITS) have attracted considerable attention due to their growing presence in various contexts. To the best of our knowledge, there have been no efforts to model large-scale ITS. In this paper, we propose a feature extraction procedure for large-scale ITS, which involves key steps such as auto-segmentation and clustering, and feature transfer learning. This procedure can be seamlessly integrated with any suitable prediction models for forecasting purposes. Specifically, we transform the automatic segmentation and clustering of ITS into the estimation of Toeplitz sparse precision matrices and assignment set. The majorization-minimization algorithm is employed to convert this highly non-convex optimization problem into two subproblems. We derive efficient dynamic programming and alternating direction method to solve these two subproblems alternately and establish their convergence properties. By employing the Joint Recurrence Plot (JRP) to image subsequence and assigning a class label to each cluster, an image dataset is constructed. Then, an appropriate neural network is chosen to train on this image dataset and used to extract features for the next step of forecasting. Real data applications demonstrate that the proposed method can effectively obtain invariant representations of the raw data and enhance forecasting performance.
Move fast, kill things: the tech startups trying to reinvent defence with Silicon Valley values
Visit tech startup Skydio's headquarters on the San Francisco peninsula in California and you're likely to find flying robots buzzing on the roof overhead. Docking stations with motorised covers open to allow small drones that resemble the TIE fighters from Star Wars films to take off; when each drone lands back again, they close. The drones can fly completely autonomously and without GPS, taking in data from onboard cameras and using AI to execute programmed missions and avoid obstacles. Skydio, with more than 740m in venture capital funding and a valuation of about 2.5bn, makes drones for the military along with civilian organisations such as police forces and utility companies. The company moved away from the consumer market in 2020 and is now the largest US drone maker.
ProHOC: Probabilistic Hierarchical Out-of-Distribution Classification via Multi-Depth Networks
Wallin, Erik, Kahl, Fredrik, Hammarstrand, Lars
Out-of-distribution (OOD) detection in deep learning has traditionally been framed as a binary task, where samples are either classified as belonging to the known classes or marked as OOD, with little attention given to the semantic relationships between OOD samples and the in-distribution (ID) classes. We propose a framework for detecting and classifying OOD samples in a given class hierarchy. Specifically, we aim to predict OOD data to their correct internal nodes of the class hierarchy, whereas the known ID classes should be predicted as their corresponding leaf nodes. Our approach leverages the class hierarchy to create a probabilistic model and we implement this model by using networks trained for ID classification at multiple hierarchy depths. We conduct experiments on three datasets with predefined class hierarchies and show the effectiveness of our method. Our code is available at https://github.com/walline/prohoc.
Dimensional optimization of single-DOF planar rigid link-flapping mechanisms for high lift and low power
Nishad, Shyam Sunder, Saxena, Anupam
Rigid link flapping mechanisms remain the most practical choice for flapping wing micro-aerial vehicles (MAVs) to carry useful payloads and onboard batteries for free flight due to their long-term durability and reliability. However, to achieve high agility and maneuverability-like insects-MAVs with these mechanisms require significant weight reduction. One approach involves using single-DOF planar rigid linkages, which are rarely optimized dimensionally for high lift and low power so that smaller motors and batteries could be used. We integrated a mechanism simulator based on a quasistatic nonlinear finite element method with an unsteady vortex lattice method-based aerodynamic analysis tool within an optimization routine. We optimized three different mechanism topologies from the literature. As a result, significant power savings were observed up to 42% in some cases, due to increased amplitude and higher lift coefficients resulting from optimized asymmetric sweeping velocity profiles. We also conducted an uncertainty analysis that revealed the need for high manufacturing tolerances to ensure reliable mechanism performance. The presented unified computational tool also facilitates the optimal selection of MAV components based on the payload and flight time requirements.