Machinery
Scalability and Sample Efficiency Analysis of Graph Neural Networks for Power System State Estimation
Kundacina, Ognjen, Gojic, Gorana, Cosovic, Mirsad, Miskovic, Dragisa, Vukobratovic, Dejan
Data-driven state estimation (SE) is becoming increasingly important in modern power systems, as it allows for more efficient analysis of system behaviour using real-time measurement data. This paper thoroughly evaluates a phasor measurement unit-only state estimator based on graph neural networks (GNNs) applied over factor graphs. To assess the sample efficiency of the GNN model, we perform multiple training experiments on various training set sizes. Additionally, to evaluate the scalability of the GNN model, we conduct experiments on power systems of various sizes. Our results show that the GNN-based state estimator exhibits high accuracy and efficient use of data. Additionally, it demonstrated scalability in terms of both memory usage and inference time, making it a promising solution for data-driven SE in modern power systems.
Design of an Adaptive Lightweight LiDAR to Decouple Robot-Camera Geometry
Chen, Yuyang, Wang, Dingkang, Thomas, Lenworth, Dantu, Karthik, Koppal, Sanjeev J.
A fundamental challenge in robot perception is the coupling of the sensor pose and robot pose. This has led to research in active vision where robot pose is changed to reorient the sensor to areas of interest for perception. Further, egomotion such as jitter, and external effects such as wind and others affect perception requiring additional effort in software such as image stabilization. This effect is particularly pronounced in micro-air vehicles and micro-robots who typically are lighter and subject to larger jitter but do not have the computational capability to perform stabilization in real-time. We present a novel microelectromechanical (MEMS) mirror LiDAR system to change the field of view of the LiDAR independent of the robot motion. Our design has the potential for use on small, low-power systems where the expensive components of the LiDAR can be placed external to the small robot. We show the utility of our approach in simulation and on prototype hardware mounted on a UAV. We believe that this LiDAR and its compact movable scanning design provide mechanisms to decouple robot and sensor geometry allowing us to simplify robot perception. We also demonstrate examples of motion compensation using IMU and external odometry feedback in hardware.
Tech-hungry agricultural machinery producers benefit from Silicon Valley layoffs. - Pakistan Lead
Due to the growing demand for skilled labor, companies are using remote employees and constructing new facilities. Media reported that Midwest CEOs are contacting Silicon Valley tech employees affected by hiring restrictions and layoffs. Deere & Co. is the world's biggest tractor manufacturer, based in Illinois. After major IT layoffs, companies like Deere & Co. aggressively recruit computer specialists to create autonomous tractors, mining vehicles, and intelligent agriculture technology. Some firms are providing remote work and creating new offices in large cities like Austin and Chicago to entice employees who don't want to migrate to the small Midwestern towns where many enterprises are situated.
Support Generation for Robot-Assisted 3D Printing with Curved Layers
Zhang, Tianyu, Huang, Yuming, Kukulski, Piotr, Dutta, Neelotpal, Fang, Guoxin, Wang, Charlie C. L.
Robot-assisted 3D printing has drawn a lot of attention by its capability to fabricate curved layers that are optimized according to different objectives. However, the support generation algorithm based on a fixed printing direction for planar layers cannot be directly applied for curved layers as the orientation of material accumulation is dynamically varied. In this paper, we propose a skeleton-based support generation method for robot-assisted 3D printing with curved layers. The support is represented as an implicit solid so that the problems of numerical robustness can be effectively avoided. The effectiveness of our algorithm is verified on a dual-material printing platform that consists of a robotic arm and a newly designed dual-material extruder. Experiments have been successfully conducted on our system to fabricate a variety of freeform models.
Identification of Power System Oscillation Modes using Blind Source Separation based on Copula Statistic
Algikar, Pooja, Mili, Lamine, Hassine, Mohsen Ben, Yarahmadi, Somayeh, Almuatazbellah, null, Boker, null
The dynamics of a power system with large penetration of renewable energy resources are becoming more nonlinear due to the intermittence of these resources and the switching of their power electronic devices. Therefore, it is crucial to accurately identify the dynamical modes of oscillation of such a power system when it is subject to disturbances to initiate appropriate preventive or corrective control actions. In this paper, we propose a high-order blind source identification (HOBI) algorithm based on the copula statistic to address these non-linear dynamics in modal analysis. The method combined with Hilbert transform (HOBI-HT) and iteration procedure (HOBMI) can identify all the modes as well as the model order from the observation signals obtained from the number of channels as low as one. We access the performance of the proposed method on numerical simulation signals and recorded data from a simulation of time domain analysis on the classical 11-Bus 4-Machine test system. Our simulation results outperform the state-of-the-art method in accuracy and effectiveness.
Long Short-Term Memory Neural Network for Temperature Prediction in Laser Powder Bed Additive Manufacturing
Yarahmadi, Ashkan Mansouri, Breuß, Michael, Hartmann, Carsten
In context of laser powder bed fusion (L-PBF), it is known that the properties of the final fabricated product highly depend on the temperature distribution and its gradient over the manufacturing plate. In this paper, we propose a novel means to predict the temperature gradient distributions during the printing process by making use of neural networks. This is realized by employing heat maps produced by an optimized printing protocol simulation and used for training a specifically tailored recurrent neural network in terms of a long short-term memory architecture. The aim of this is to avoid extreme and inhomogeneous temperature distribution that may occur across the plate in the course of the printing process. In order to train the neural network, we adopt a well-engineered simulation and unsupervised learning framework. To maintain a minimized average thermal gradient across the plate, a cost function is introduced as the core criteria, which is inspired and optimized by considering the well-known traveling salesman problem (TSP). As time evolves the unsupervised printing process governed by TSP produces a history of temperature heat maps that maintain minimized average thermal gradient. All in one, we propose an intelligent printing tool that provides control over the substantial printing process components for L-PBF, i.e.\ optimal nozzle trajectory deployment as well as online temperature prediction for controlling printing quality.
Interview with AI Chatbot ChatGPT on the 3D Printing Market - 3Dnatives
Our interview today is truly unique: we have interviewed artificial intelligence (AI)! We wanted to test the now well-known ChatGPT and thought we would interview it as we would a 3D printing expert. ChatGPT (short for Generative Pre-trained Transformer) is a chatbot system developed by OpenAI, based on an artificial intelligence model using machine learning technology. When we asked it to introduce itself, it told us, "I'm here to help you solve your problems. I will be glad to help you in any way I can."
Hybrid thermal modeling of additive manufacturing processes using physics-informed neural networks for temperature prediction and parameter identification
Liao, Shuheng, Xue, Tianju, Jeong, Jihoon, Webster, Samantha, Ehmann, Kornel, Cao, Jian
Understanding the thermal behavior of additive manufacturing (AM) processes is crucial for enhancing the quality control and enabling customized process design. Most purely physics-based computational models suffer from intensive computational costs and the need of calibrating unknown parameters, thus not suitable for online control and iterative design application. Data-driven models taking advantage of the latest developed computational tools can serve as a more efficient surrogate, but they are usually trained over a large amount of simulation data and often fail to effectively use small but high-quality experimental data. In this work, we developed a hybrid physics-based data-driven thermal modeling approach of AM processes using physics-informed neural networks. Specifically, partially observed temperature data measured from an infrared camera is combined with the physics laws to predict full-field temperature history and to discover unknown material and process parameters. In the numerical and experimental examples, the effectiveness of adding auxiliary training data and using the pretrained model on training efficiency and prediction accuracy, as well as the ability to identify unknown parameters with partially observed data, are demonstrated. The results show that the hybrid thermal model can effectively identify unknown parameters and capture the full-field temperature accurately, and thus it has the potential to be used in iterative process design and real-time process control of AM.
Diatom-inspired architected materials using language-based deep learning: Perception, transformation and manufacturing
Learning from nature has been a quest of humanity for millennia. While this has taken the form of humans assessing natural designs such as bones, butterfly wings, or spider webs, we can now achieve generating designs using advanced computational algorithms. In this paper we report novel biologically inspired designs of diatom structures, enabled using transformer neural networks, using natural language models to learn, process and transfer insights across manifestations. We illustrate a series of novel diatom-based designs and also report a manufactured specimen, created using additive manufacturing. The method applied here could be expanded to focus on other biological design cues, implement a systematic optimization to meet certain design targets, and include a hybrid set of material design sets.