Energy
Feed-forward Disturbance Compensation for Station Keeping in Wave-dominated Environments
Walker, Kyle L., Stokes, Adam A., Kiprakis, Aristides, Giorgio-Serchi, Francesco
When deploying robots in shallow ocean waters, wave disturbances can be significant, highly dynamic and pose problems when operating near structures; this is a key limitation of current control strategies, restricting the range of conditions in which subsea vehicles can be deployed. To improve dynamic control and offer a higher level of robustness, this work proposes a Cascaded Proportional-Derivative (C-PD) with Feed-forward (FF) control scheme for disturbance mitigation, exploring the concept of explicitly using disturbance estimations to counteract state perturbations. Results demonstrate that the proposed controller is capable of higher performance in contrast to a standard C-PD controller, with an average reduction of ~48% witnessed across various sea states. Additional analysis also investigated performance when considering coarse estimations featuring inaccuracies; average improvements of ~17% demonstrate the effectiveness of the proposed strategy to handle these uncertainties. The proposal in this work shows promise for improved control without a drastic increase in required computing power; if coupled with sufficient sensors, state estimation techniques and prediction algorithms, utilising feed-forward compensating control actions offers a potential solution to improve vehicle control under wave-induced disturbances.
The Capacity and Robustness Trade-off: Revisiting the Channel Independent Strategy for Multivariate Time Series Forecasting
Han, Lu, Ye, Han-Jia, Zhan, De-Chuan
Multivariate time series data comprises various channels of variables. The multivariate forecasting models need to capture the relationship between the channels to accurately predict future values. However, recently, there has been an emergence of methods that employ the Channel Independent (CI) strategy. These methods view multivariate time series data as separate univariate time series and disregard the correlation between channels. Surprisingly, our empirical results have shown that models trained with the CI strategy outperform those trained with the Channel Dependent (CD) strategy, usually by a significant margin. Nevertheless, the reasons behind this phenomenon have not yet been thoroughly explored in the literature. This paper provides comprehensive empirical and theoretical analyses of the characteristics of multivariate time series datasets and the CI/CD strategy. Our results conclude that the CD approach has higher capacity but often lacks robustness to accurately predict distributionally drifted time series. In contrast, the CI approach trades capacity for robust prediction. Practical measures inspired by these analyses are proposed to address the capacity and robustness dilemma, including a modified CD method called Predict Residuals with Regularization (PRReg) that can surpass the CI strategy. We hope our findings can raise awareness among researchers about the characteristics of multivariate time series and inspire the construction of better forecasting models.
A Self-attention Knowledge Domain Adaptation Network for Commercial Lithium-ion Batteries State-of-health Estimation under Shallow Cycles
Chen, Xin, Qin, Yuwen, Zhao, Weidong, Yang, Qiming, Cai, Ningbo, Wu, Kai
Accurate state-of-health (SOH) estimation is critical to guarantee the safety, efficiency and reliability of battery-powered applications. Most SOH estimation methods focus on the 0-100\% full state-of-charge (SOC) range that has similar distributions. However, the batteries in real-world applications usually work in the partial SOC range under shallow-cycle conditions and follow different degradation profiles with no labeled data available, thus making SOH estimation challenging. To estimate shallow-cycle battery SOH, a novel unsupervised deep transfer learning method is proposed to bridge different domains using self-attention distillation module and multi-kernel maximum mean discrepancy technique. The proposed method automatically extracts domain-variant features from charge curves to transfer knowledge from the large-scale labeled full cycles to the unlabeled shallow cycles. The CALCE and SNL battery datasets are employed to verify the effectiveness of the proposed method to estimate the battery SOH for different SOC ranges, temperatures, and discharge rates. The proposed method achieves a root-mean-square error within 2\% and outperforms other transfer learning methods for different SOC ranges. When applied to batteries with different operating conditions and from different manufacturers, the proposed method still exhibits superior SOH estimation performance. The proposed method is the first attempt at accurately estimating battery SOH under shallow-cycle conditions without needing a full-cycle characteristic test.
A Systematic Survey of Control Techniques and Applications in Connected and Automated Vehicles
Liu, Wei, Hua, Min, Deng, Zhiyun, Meng, Zonglin, Huang, Yanjun, Hu, Chuan, Song, Shunhui, Gao, Letian, Liu, Changsheng, Shuai, Bin, Khajepour, Amir, Xiong, Lu, Xia, Xin
Vehicle control is one of the most critical challenges in autonomous vehicles (AVs) and connected and automated vehicles (CAVs), and it is paramount in vehicle safety, passenger comfort, transportation efficiency, and energy saving. This survey attempts to provide a comprehensive and thorough overview of the current state of vehicle control technology, focusing on the evolution from vehicle state estimation and trajectory tracking control in AVs at the microscopic level to collaborative control in CAVs at the macroscopic level. First, this review starts with vehicle key state estimation, specifically vehicle sideslip angle, which is the most pivotal state for vehicle trajectory control, to discuss representative approaches. Then, we present symbolic vehicle trajectory tracking control approaches for AVs. On top of that, we further review the collaborative control frameworks for CAVs and corresponding applications. Finally, this survey concludes with a discussion of future research directions and the challenges. This survey aims to provide a contextualized and in-depth look at state of the art in vehicle control for AVs and CAVs, identifying critical areas of focus and pointing out the potential areas for further exploration.
Despite Iranian attack killing American abroad, Biden pursues nuclear deal with ayatollah's regime
National security analyst Dr. Rebecca Grant joins "Fox News Live" to weigh in on what steps President Biden can take to rein in Iranian-backed militia strikes on U.S. bases in Syria. The Iranian regime's recent drone attack on an American base in Syria, which resulted in the murder of a U.S. contractor, has not deterred the Biden administration from pursuing the controversial nuclear pact with Tehran that would dramatically enrich the coffers of the Islamic Republic. The White House remains wedded to the Joint Comprehensive Plan of Action (JCPOA) โ the formal name for the Iran nuclear deal โ that "would allow Tehran to access up to $275 billion in financial benefits during its first year in effect and $1 trillion by 2030." Veteran Iran experts have argued that the JCPOA is no longer tenable because it is riddled with serious defects about deterring Iran's malign behavior, including failing to stop Tehran's ongoing drone attacks against Americans. Iran's regime was caught enriching uranium to 84% purity in February โ just 6% short of weapons-grade uranium for a nuclear weapon.
Without AI, We Won't Meet ESG Goals And Address Climate Change - Liwaiwai
The current state of ESG programmes is not making an adequate difference for climate change fast enough. AI can help provide comprehensive ESG management solutions, reporting capabilities and actionable emissions insights. AI can ingest huge amounts of data, pull signal from noise and give companies a roadmap to meet ESG goals that make a real difference. The world is in a precarious condition due to climate change. Not surprisingly, companies are facing immense pressure from investors and customers to improve their transparency and performance on ESG issues, and many are getting positive feedback for their success. But the current stateโฆ
How Industrial Automation is Improving Safety in the Oil & Gas Industry
The oil and gas industry is one of the most dangerous and hazardous industries in the world. With a history of catastrophic accidents and a high rate of fatalities and injuries, the need for effective safety measures is paramount. Industrial automation technologies, such as robotics and artificial intelligence (AI), are being increasingly adopted to improve safety standards and reduce the risk of accidents and injuries. Industrial automation technologies have changed the way we work, with the oil and gas industry making use of robotics and AI to enhance safety measures. With a clear emphasis on improving safety in the workplace, these automation technologies have enabled advanced monitoring, analysis and process automation, eliminating human error and reducing accidents and injuries. Oil and gas production activities are inherently dangerous, with the possibility of explosions, oil spills, equipment failure, and other hazards.
FLUID: A Unified Evaluation Framework for Flexible Sequential Data
Wallingford, Matthew, Kusupati, Aditya, Alizadeh-Vahid, Keivan, Walsman, Aaron, Kembhavi, Aniruddha, Farhadi, Ali
Modern ML methods excel when training data is IID, large-scale, and well labeled. Learning in less ideal conditions remains an open challenge. The sub-fields of few-shot, continual, transfer, and representation learning have made substantial strides in learning under adverse conditions; each affording distinct advantages through methods and insights. These methods address different challenges such as data arriving sequentially or scarce training examples, however often the difficult conditions an ML system will face over its lifetime cannot be anticipated prior to deployment. Therefore, general ML systems which can handle the many challenges of learning in practical settings are needed. To foster research towards the goal of general ML methods, we introduce a new unified evaluation framework - FLUID (Flexible Sequential Data). FLUID integrates the objectives of few-shot, continual, transfer, and representation learning while enabling comparison and integration of techniques across these subfields. In FLUID, a learner faces a stream of data and must make sequential predictions while choosing how to update itself, adapt quickly to novel classes, and deal with changing data distributions; while accounting for the total amount of compute. We conduct experiments on a broad set of methods which shed new insight on the advantages and limitations of current solutions and indicate new research problems to solve. As a starting point towards more general methods, we present two new baselines which outperform other evaluated methods on FLUID. Project page: https://raivn.cs.washington.edu/projects/FLUID/.
Neural Laplace Control for Continuous-time Delayed Systems
Holt, Samuel, Hรผyรผk, Alihan, Qian, Zhaozhi, Sun, Hao, van der Schaar, Mihaela
Many real-world offline reinforcement learning (RL) problems involve continuous-time environments with delays. Such environments are characterized by two distinctive features: firstly, the state x(t) is observed at irregular time intervals, and secondly, the current action a(t) only affects the future state x(t + g) with an unknown delay g > 0. A prime example of such an environment is satellite control where the communication link between earth and a satellite causes irregular observations and delays. Existing offline RL algorithms have achieved success in environments with irregularly observed states in time or known delays. However, environments involving both irregular observations in time and unknown delays remains an open and challenging problem. To this end, we propose Neural Laplace Control, a continuous-time model-based offline RL method that combines a Neural Laplace dynamics model with a model predictive control (MPC) planner--and is able to learn from an offline dataset sampled with irregular time intervals from an environment that has a inherent unknown constant delay. We show experimentally on continuous-time delayed environments it is able to achieve near expert policy performance.
HybridFusion: LiDAR and Vision Cross-Source Point Cloud Fusion
Wang, Yu, Bu, Shuhui, Chen, Lin, Dong, Yifei, Li, Kun, Cao, Xuefeng, Li, Ke
Recently, cross-source point cloud registration from different sensors has become a significant research focus. However, traditional methods confront challenges due to the varying density and structure of cross-source point clouds. In order to solve these problems, we propose a cross-source point cloud fusion algorithm called HybridFusion. It can register cross-source dense point clouds from different viewing angle in outdoor large scenes. The entire registration process is a coarse-to-fine procedure. First, the point cloud is divided into small patches, and a matching patch set is selected based on global descriptors and spatial distribution, which constitutes the coarse matching process. To achieve fine matching, 2D registration is performed by extracting 2D boundary points from patches, followed by 3D adjustment. Finally, the results of multiple patch pose estimates are clustered and fused to determine the final pose. The proposed approach is evaluated comprehensively through qualitative and quantitative experiments. In order to compare the robustness of cross-source point cloud registration, the proposed method and generalized iterative closest point method are compared. Furthermore, a metric for describing the degree of point cloud filling is proposed. The experimental results demonstrate that our approach achieves state-of-the-art performance in cross-source point cloud registration.