Evolving AI-Driven Workflow Management, Part B: Non-Unique Engineering Workflows and Scalable Open-weight Agents

Workflow engines play an important role for modern engineering, especially when the complexity of the subject is high. Large Language Models could potentially provide a powerful user interface, if they can be set up to reliably transform natural language inputs into correct workflow instructions. Previous works investigated this possibility with a single proprietary Large Language Model as the only involved AI system. The accompanying part A of the current work enhances that method by implementing a multi-agent architecture of proprietary models and Open Weight Models resulting in reduced context window sizes, and by also incorporating a data provenance system. The present part B addresses the real-world problem of ambiguity of workflows and how to solve this problem in a scalable manner. The main contributions are twofold. First, the non-uniqueness of results of queries to knowledge graphs of realistic workflows for computational engineering is classified as either "by multi-fidelity" or "by redundancy". Second, it is shown that LLMs with large context window can be capable of resolving such non-uniqueness whereas fine-tuned Small Language Models contribute in other ways to the scalability of the multi-agent system of part A

Comparison of high performance hybrid variable reluctance fast steering mirrors

Actuated mirrors are a key element in free-space optical communications. This paper compares the two high performance, commercially available actuators with a hybrid variable reluctance drive principle. They feature a mechanical range of up to 3 degrees and achieve closed-loop bandwidths of more than 1 kHz in combination with eddy-current sensors. It is shown, that the choice of driver is closely linked to their achievable dynamics. In particular, the performance in the application area of optical communication on satellites is analyzed. Therefore, in addition to the dynamic properties, the integration, their power consumption and suppression of vibrations is also being considered. To ensure comparability, a parameter tuning algorithm is used. The breadboard utilizes the same control software and hardware for both devices. The FSM20B shows better passive rejection against external vibrations, a lower average power consumption, and allows the exchange of its angular sensors. The FSM3000 achieves a better steady-state jitter, features a larger operating range and is more compact in size with precalibrated, internal sensors

Motion Planning for Humanoid Locomotion: Applications to Homelike Environments

"What can your humanoid robot do?" is probably the most commonly asked question that we, as roboticists, have to answer when interacting with the general public. Often, the question is framed in the familiar household or office setting, with implied expectations of robust locomotion on uneven and cluttered terrain, and compliant interaction with people, objects, and the environment. Moreover, the question implies the existence within the humanoid robot of a set of embodied loco-manipulation skills implemented by a motion planner, skills that are retrievable when given the corresponding commands. In this article, we formulate an answer to this question in the form of an efficient, modular, and extensible motion planner. We demonstrate its use with three challenging scenarios, designed to highlight both the robot's safe operation and its precise movement in unstructured environments. Additionally, we discuss key techniques derived from our experience in the practical implementation of torque-controlled humanoid robots

Sentinel-1-Aided Mutual Calibration of TanDEM-X DEMs for the Estimation of Height and Volume Changes

Digital elevation models (DEM) derived from TanDEM-X single-pass interferometric SAR data are widely used for a large vary of applications. One of the main application fields regards the monitoring of topographic changes, which can be properly estimated by differentiating two DEM scenes acquired at different times. In this scenario, a critical aspect is represented by the precise mutual calibration of the two DEMs, which are normally affected by residual offsets and tilts caused by uncertainties in the baseline determination. This calibration is in general performed by utilizing reference tie-points, whose location and height is known a priori, or estimated through other reference sensors, such as GPS or LiDAR data. The manual procedure is time-consuming and can be jeopardized by the absence of available external reference points. In this paper, we present a novel technique for performing an automatic selection of reliable natural tie-points from Sentinel-1 repeat-pass time-series, by exploiting persistent scatterers candidates, and we discuss their applicability to TanDEM-X data. We propose a novel method for retrieving a set of reliable natural calibration targets and for performing an effective mutual calibration of TanDEM-X time-tagged DEMs. The approach is validated by considering the estimation of lava field volumes in the test-case scenario of the volcanic eruptions in the Reykjanes Peninsula, Iceland, occurred between 2021 and 2023. Thanks to the continuous global coverage of Sentinel-1, this approach can be applied when no a priori knowledge on reference tie-points is available, allowing for the precise estimation of height and volume changes

Development of Short-Range Laminar Aircraft: Conceptual Design with Integrated System Sizing

The aviation industry is currently facing significant pressure to enhance its sustainability by increasing aircraft energy efficiency and reducing its climate impact. A promising approach to fulfilling these demands is to improve the aircraft's aerodynamic performance through drag reduction by implementing laminar flow technologies, particularly Natural Laminar Flow (NLF) or Hybrid Laminar Flow Control (HLFC). Prior works assessing laminar flow technologies have mostly focused on evaluating their aerodynamic performance and, in the case of the HLFC, on the influence of system design. The impact of these technologies on the overall aircraft performance has received only limited consideration, with the majority of studies focusing on long-range aircraft, utilizing simplified models for HLFC systems, and considering only one laminar flow technology at a time. This study adopts a holistic approach to assess the potential fuel savings that could be achieved by combined application of NLF and HLFC technologies on the various components of a short-to-medium range aircraft concept, with an intended entry into service in 2035. To achieve this objective, a conceptual aircraft design process is employed. This process captures the aerodynamic effects of laminar flow technologies and fully integrates the HLFC system design to provide an accurate estimate of aircraft performance. The findings of this study reveal a potential for fuel savings of 5.9% on the design mission through the combined application of NLF and HLFC, compared to a turbulent aircraft with an equivalent technology level. Additionally, the results indicate that strategic combination of the two technologies on a single component can significantly reduce complexity while further enhancing fuel savings. A failure analysis also provides an initial estimate of the impact of various failure scenarios on the aircraft's performance. These findings demonstrate that, despite the aircraft's short range, the combined implementation of the two laminar flow technologies offers a potential for fuel savings with reduced complexity, motivating further research in their application to this aircraft category

Sensitivity of Propeller Whirl Flutter With Respect to Blade Parameters

New methods for propeller whirl flutter prediction emerge, enabling aeroelastic engineers to include more modeling parameters and more sophisticated methods into their analysis. However, the sensitivity of propeller whirl flutter with respect to modeling parameters like airfoil characteristics, blade sweep and stiffness is not clear. This makes it hard to decide, on which blade parameters to focus when choosing a modeling tool or a validation procedure. This paper aims to provide a comprehensive overview of the sensitivity of whirl flutter with respect to the above-mentioned blade parameters, identifying those with the highest impact on stability. For this purpose, the Transfer-Matrix method is used to assess the whirl flutter stability of the simplified pylon model and a generic turboprop aircraft, using a rigid and a flexible set of parametric propeller blades. The results show that blade sweep and an increase in stiffness are strongly destabilizing for whirl flutter. Regarding the blade aerodynamics, the lift characteristics (steady lift offset and lift curve slope) and their radial distribution are the most important aerodynamic parameters, followed by drag and last the airfoil moment characteristics