Energy
The Morning After: Microsoft's new Xbox controller is partially made of ground-up CDs
Microsoft has announced a new, slightly more sustainable Xbox controller. Arriving as an Earth Day promotion, the Xbox Remix Special Edition wireless controller uses recycled materials from old gamepads, auto headlight covers and reclaimed CDs (among other sources) to give each accessory a unique look – but no special functionality. Microsoft describes the combination of recycled resins with regrind as creating "custom, earth-tone colors with subtle variations, swirling, markings, and texturing – giving each Remix Special Edition controller its own look and feel." While it's hard to see that on the press images, it should result in a satisfying textured pattern on the bumpers and side grip. The company also bundles an Xbox Rechargeable Battery Pack with each gamepad, ensuring fewer AA batteries head to landfills.
Design and Motion Planning for a Reconfigurable Robotic Base
Pankert, Johannes, Valsecchi, Giorgio, Baret, Davide, Zehnder, Jon, Pietrasik, Lukasz L., Bjelonic, Marko, Hutter, Marco
A robotic platform for mobile manipulation needs to satisfy two contradicting requirements for many real-world applications: A compact base is required to navigate through cluttered indoor environments, while the support needs to be large enough to prevent tumbling or tip over, especially during fast manipulation operations with heavy payloads or forceful interaction with the environment. This paper proposes a novel robot design that fulfills both requirements through a versatile footprint. It can reconfigure its footprint to a narrow configuration when navigating through tight spaces and to a wide stance when manipulating heavy objects. Furthermore, its triangular configuration allows for high-precision tasks on uneven ground by preventing support switches. A model predictive control strategy is presented that unifies planning and control for simultaneous navigation, reconfiguration, and manipulation. It converts task-space goals into whole-body motion plans for the new robot. The proposed design has been tested extensively with a hardware prototype. The footprint reconfiguration allows to almost completely remove manipulation-induced vibrations. The control strategy proves effective in both lab experiment and during a real-world construction task.
Data Quality Over Quantity: Pitfalls and Guidelines for Process Analytics
Siang, Lim C., Elnawawi, Shams, Rippon, Lee D., O'Connor, Daniel L., Gopaluni, R. Bhushan
A significant portion of the effort involved in advanced process control, process analytics, and machine learning involves acquiring and preparing data. Literature often emphasizes increasingly complex modelling techniques with incremental performance improvements. However, when industrial case studies are published they often lack important details on data acquisition and preparation. Although data pre-processing is unfairly maligned as trivial and technically uninteresting, in practice it has an out-sized influence on the success of real-world artificial intelligence applications. This work describes best practices for acquiring and preparing operating data to pursue data-driven modelling and control opportunities in industrial processes. We present practical considerations for pre-processing industrial time series data to inform the efficient development of reliable soft sensors that provide valuable process insights.
Emerging trends in machine learning for computational fluid dynamics
Vinuesa, Ricardo, Brunton, Steve
Machine learning (ML) is a rapidly developing field of research that has transformed the state-of-the-art capabilities for many traditional tasks in computer science, such as image classification and captioning, natural language processing, and recommender systems. The numerous success stories of ML have led to widespread adoption in the scientific and engineering communities as well, fueled by a growing wealth of data, computing resources, and advanced optimization algorithms. This is especially true in the field of fluid mechanics, where emerging technologies complement existing computational and experimental methods, providing a unified approach to building models from data [5]. Despite these advancements, there remains a gap in understanding how ML can be best integrated with computational fluid dynamics (CFD). This paper aims to explore the synergies between ML and CFD, showcasing the potential benefits and challenges in combining these fields. ML can advance CFD in areas such as turbulence modeling, development of inflow boundary conditions, subgrid-scale models for large-eddy simulations (LES), closures for Reynolds-averaged Navier-Stokes (RANS) equations, development of reduced-order models (ROMs), and flow control [29]. Our approach is to first examine established techniques, such as proper-orthogonal decomposition (POD) and dynamic-mode decomposition (DMD), alongside deep-learning techniques with autoencoders. Next, we delve into emerging opportunities where ML and CFD can be further integrated, highlighting ongoing challenges and potential solutions. We conclude by summarizing the insights gained and potential future directions for this interdisciplinary research.
GenPhys: From Physical Processes to Generative Models
Liu, Ziming, Luo, Di, Xu, Yilun, Jaakkola, Tommi, Tegmark, Max
Since diffusion models (DM) and the more recent Poisson flow generative models (PFGM) are inspired by physical processes, it is reasonable to ask: Can physical processes offer additional new generative models? We show that the answer is yes. We introduce a general family, Generative Models from Physical Processes (GenPhys), where we translate partial differential equations (PDEs) describing physical processes to generative models. We show that generative models can be constructed from s-generative PDEs (s for smooth). GenPhys subsume the two existing generative models (DM and PFGM) and even give rise to new families of generative models, e.g., "Yukawa Generative Models" inspired from weak interactions. On the other hand, some physical processes by default do not belong to the GenPhys family, e.g., the wave equation and the Schr\"{o}dinger equation, but could be made into the GenPhys family with some modifications. Our goal with GenPhys is to explore and expand the design space of generative models.
Learning Stability Attention in Vision-based End-to-end Driving Policies
Wang, Tsun-Hsuan, Xiao, Wei, Chahine, Makram, Amini, Alexander, Hasani, Ramin, Rus, Daniela
Modern end-to-end learning systems can learn to explicitly infer control from perception. However, it is difficult to guarantee stability and robustness for these systems since they are often exposed to unstructured, high-dimensional, and complex observation spaces (e.g., autonomous driving from a stream of pixel inputs). We propose to leverage control Lyapunov functions (CLFs) to equip end-to-end vision-based policies with stability properties and introduce stability attention in CLFs (att-CLFs) to tackle environmental changes and improve learning flexibility. We also present an uncertainty propagation technique that is tightly integrated into att-CLFs. We demonstrate the effectiveness of att-CLFs via comparison with classical CLFs, model predictive control, and vanilla end-to-end learning in a photo-realistic simulator and on a real full-scale autonomous vehicle.
Hybrid Zonotopes Exactly Represent ReLU Neural Networks
Ortiz, Joshua, Vellucci, Alyssa, Koeln, Justin, Ruths, Justin
We show that hybrid zonotopes offer an equivalent representation of feed-forward fully connected neural networks with ReLU activation functions. Our approach demonstrates that the complexity of binary variables is equal to the total number of neurons in the network and hence grows linearly in the size of the network. We demonstrate the utility of the hybrid zonotope formulation through three case studies including nonlinear function approximation, MPC closed-loop reachability and verification, and robustness of classification on the MNIST dataset.
MethaneMapper: Spectral Absorption aware Hyperspectral Transformer for Methane Detection
Kumar, Satish, Arevalo, Ivan, Iftekhar, ASM, Manjunath, B S
Methane (CH$_4$) is the chief contributor to global climate change. Recent Airborne Visible-Infrared Imaging Spectrometer-Next Generation (AVIRIS-NG) has been very useful in quantitative mapping of methane emissions. Existing methods for analyzing this data are sensitive to local terrain conditions, often require manual inspection from domain experts, prone to significant error and hence are not scalable. To address these challenges, we propose a novel end-to-end spectral absorption wavelength aware transformer network, MethaneMapper, to detect and quantify the emissions. MethaneMapper introduces two novel modules that help to locate the most relevant methane plume regions in the spectral domain and uses them to localize these accurately. Thorough evaluation shows that MethaneMapper achieves 0.63 mAP in detection and reduces the model size (by 5x) compared to the current state of the art. In addition, we also introduce a large-scale dataset of methane plume segmentation mask for over 1200 AVIRIS-NG flight lines from 2015-2022. It contains over 4000 methane plume sites. Our dataset will provide researchers the opportunity to develop and advance new methods for tackling this challenging green-house gas detection problem with significant broader social impact. Dataset and source code are public
A dynamic Bayesian optimized active recommender system for curiosity-driven Human-in-the-loop automated experiments
Biswas, Arpan, Liu, Yongtao, Creange, Nicole, Liu, Yu-Chen, Jesse, Stephen, Yang, Jan-Chi, Kalinin, Sergei V., Ziatdinov, Maxim A., Vasudevan, Rama K.
Optimization of experimental materials synthesis and characterization through active learning methods has been growing over the last decade, with examples ranging from measurements of diffraction on combinatorial alloys at synchrotrons, to searches through chemical space with automated synthesis robots for perovskites. In virtually all cases, the target property of interest for optimization is defined apriori with limited human feedback during operation. In contrast, here we present the development of a new type of human in the loop experimental workflow, via a Bayesian optimized active recommender system (BOARS), to shape targets on the fly, employing human feedback. We showcase examples of this framework applied to pre-acquired piezoresponse force spectroscopy of a ferroelectric thin film, and then implement this in real time on an atomic force microscope, where the optimization proceeds to find symmetric piezoresponse amplitude hysteresis loops. It is found that such features appear more affected by subsurface defects than the local domain structure. This work shows the utility of human-augmented machine learning approaches for curiosity-driven exploration of systems across experimental domains. The analysis reported here is summarized in Colab Notebook for the purpose of tutorial and application to other data: https://github.com/arpanbiswas52/varTBO
Adaptive Headway Motion Control and Motion Prediction for Safe Unicycle Motion Design
İşleyen, Aykut, van de Wouw, Nathan, Arslan, Ömür
Differential drive robots that can be modeled as a kinematic unicycle are a standard mobile base platform for many service and logistics robots. Safe and smooth autonomous motion around obstacles is a crucial skill for unicycle robots to perform diverse tasks in complex environments. A classical control approach for unicycle control is feedback linearization using a headway point at a fixed headway distance in front of the unicycle. The unicycle headway control brings the headway point to a desired goal location by embedding a linear headway reference dynamics, which often results in an undesired offset for the actual unicycle position. In this paper, we introduce a new unicycle headway control approach with an adaptive headway distance that overcomes this limitation, i.e., when the headway point reaches the goal the unicycle position is also at the goal. By systematically analyzing the closed-loop unicycle motion under the adaptive headway controller, we design analytical feedback motion prediction methods that bound the closed-loop unicycle position trajectory and so can be effectively used for safety assessment and safe unicycle motion design around obstacles. We present an application of adaptive headway motion control and motion prediction for safe unicycle path following around obstacles in numerical simulations.