pwc-archive/papers-with-abstracts huggingface dataset:
First Principles based High-precision Modelling and Identification of Piezoelectric Fast Steering Mirror
Authors: Sen yang, Xiaofeng Li
Date: 2024-12-11 00:00:00

We establish a high-precision composite model for a piezoelectric fast steering mirror (PFSM) using a Hammerstein structure. A novel asymmetric Bouc-Wen model is proposed to describe the nonlinear rate-independent hysteresis, while a dynamic model is derived to represent the linear rate-dependent component. By analyzing the physical process from the displacement of the piezoelectric actuator to the angle of the PFSM, cross-axis coupling is modeled based on first principles. Given the dynamic isolation of each module on different frequency scales, a step-by-step method for model parameter identification is carried out. Finally, experimental results demonstrate that the identified parameters can accurately represent the hysteresis, creep, and mechanical dynamic characteristics of the PFSM. Furthermore, by comparing the outputs of the identified model with the real PFSM under different excitation signals, the effectiveness of the proposed dual-input dual-output composite model is validated.
Thévenin Equivalent Parameters Identification Based on Statistical Characteristics of System Ambient Data
Authors: Boying Zhou, Chen Shen, Kexuan Tang
Date: 2024-12-11 00:00:00

This paper proposes a novel method for identifying Th\'evenin equivalent parameters (TEP) in power system, based on the statistical characteristics of the system's stochastic response. The method leverages stochastic fluctuation data under steady-state grid conditions and applies sliding window techniques to compute sensitivity parameters between voltage magnitude, current magnitude and power. This enables high-accuracy and robust TEP identification. In contrast to traditional methods, the proposed approach does not rely on large disturbances or probing signals but instead utilizes the natural fluctuation behavior of the system. Additionally, the method supports distributed implementation using local measurements of voltage magnitude, current magnitude, and power, offering significant practical value for engineering applications. The theoretical analysis demonstrates the method's robustness in the presence of low signal-to-noise ratio (SNR), asynchronous measurements, and data collinearity issues. Simulation results further confirm the effectiveness of the proposed method in diverse practical scenarios, demonstrating its ability to consistently provide accurate and reliable identification of TEP using system ambient data.
Toward Near-Globally Optimal Nonlinear Model Predictive Control via Diffusion Models
Authors: Tzu-Yuan Huang, Armin Lederer, Nicolas Hoischen, Jan Brüdigam, Xuehua Xiao, Stefan Sosnowski, Sandra Hirche
Date: 2024-12-11 00:00:00
Tasks: Model Predictive Control

Achieving global optimality in nonlinear model predictive control (NMPC) is challenging due to the non-convex nature of the underlying optimization problem. Since commonly employed local optimization techniques depend on carefully chosen initial guesses, this non-convexity often leads to suboptimal performance resulting from local optima. To overcome this limitation, we propose a novel diffusion model-based approach for near-globally optimal NMPC consisting of an offline and an online phase. The offline phase employs a local optimizer to sample from the distribution of optimal NMPC control sequences along generated system trajectories through random initial guesses. Subsequently, the generated diverse dataset is used to train a diffusion model to reflect the multi-modal distribution of optima. In the online phase, the trained model is leveraged to efficiently perform a variant of random shooting optimization to obtain near-globally optimal control sequences without relying on any initial guesses or online NMPC solving. The effectiveness of our approach is illustrated in a numerical simulation indicating high performance benefits compared to direct neural network approximations of NMPC and significantly lower computation times than online solving NMPC using global optimizers.
Neural Operator Feedback for a First-Order PIDE with Spatially-Varying State Delay
Authors: Jie Qi, Jiaqi Hu, Jing Zhang, Miroslav Krstic
Date: 2024-12-11 00:00:00

A transport PDE with a spatial integral and recirculation with constant delay has been a benchmark for neural operator approximations of PDE backstepping controllers. Introducing a spatially-varying delay into the model gives rise to a gain operator defined through integral equations which the operator's input -- the varying delay function -- enters in previously unencountered manners, including in the limits of integration and as the inverse of the `delayED time' function. This, in turn, introduces novel mathematical challenges in estimating the operator's Lipschitz constant. The backstepping kernel function having two branches endows the feedback law with a two-branch structure, where only one of the two feedback branches depends on both of the kernel branches. For this rich feedback structure, we propose a neural operator approximation of such a two-branch feedback law and prove the approximator to be semiglobally practically stabilizing. With numerical results we illustrate the training of the neural operator and its stabilizing capability.
Rigid Communication Topologies: Impact on Stability, Safety, Energy Consumption, Passenger Comfort, and Robustness of Vehicular Platoons
Authors: Amir Zakerimanesh, Tony Zhijun Qiu, Mahdi Tavakoli
Date: 2024-12-11 00:00:00

This paper investigates the impact of rigid communication topologies (RCTs) on the performance of vehicular platoons, aiming to identify beneficial features in RCTs that enhance vehicles behavior. We introduce four performance metrics, focusing on safety, energy consumption, passenger comfort, and robustness of vehicular platoons. The safety metric is based on momentary distances between neighboring vehicles, their relative velocities, and relative accelerations. Thus, to have access to these relative values, we formulate the coupled dynamics between pairs of neighboring vehicles, considering initial conditions (position, velocity, acceleration), leader vehicle's velocity/acceleration trajectory, deployed RCT, and vehicles' parity/disparity. By decoupling the dynamics using a mapping matrix structured on deployed RCT, vehicles' features, and control gains, precise formulations for distance errors, relative velocities, and relative accelerations between all neighboring vehicles, over the travel time, are obtained. Comparing performance metric results across RCTs highlights that downstream information transmission-from vehicles ahead, particularly the leader vehicle, to vehicles behind-significantly enhances platoon stability, safety, energy consumption, and passenger comfort metrics. Conversely, receiving state information from vehicles behind degrades metrics, compromising safety, increasing energy consumption, and reducing passenger comfort. These findings underscore that forward-looking, leader-centric communications between vehicles markedly enhance platoon efficiency and safety.
Offset-free model predictive control: stability under plant-model mismatch
Authors: Steven J. Kuntz, James B. Rawlings
Date: 2024-12-11 00:00:00
Tasks: model, Model Predictive Control

We present the first general stability results for nonlinear offset-free model predictive control (MPC). Despite over twenty years of active research, the offset-free MPC literature has not shaken the assumption of closed-loop stability for establishing offset-free performance. In this paper, we present a nonlinear offset-free MPC design that is robustly stable with respect to the tracking errors, and thus achieves offset-free performance, despite plant-model mismatch and persistent disturbances. Key features and assumptions of this design include quadratic costs, differentiability of the plant and model functions, constraint backoffs at steady state, and a robustly stable state and disturbance estimator. We first establish nominal stability and offset-free performance. Then, robustness to state and disturbance estimate errors and setpoint and disturbance changes is demonstrated. Finally, the results are extended to sufficiently small plant-model mismatch. The results are illustrated by numerical examples.
A Survey of Open-Source Power System Dynamic Simulators with Grid-Forming Inverter for Machine Learning Applications
Authors: Tong Su, Jiangkai Peng, Alaa Selim, Junbo Zhao, Jin Tan
Date: 2024-12-11 00:00:00

The emergence of grid-forming (GFM) inverter technology and the increasing role of machine learning in power systems highlight the need for evaluating the latest dynamic simulators. Open-source simulators offer distinct advantages in this field, being both free and highly customizable, which makes them well-suited for scientific research and validation of the latest models and methods. This paper provides a comprehensive survey and comparison of the latest open-source simulators that support GFM, with a focus on their capabilities and performance in machine-learning applications.
Survey on Human-Vehicle Interactions and AI Collaboration for Optimal Decision-Making in Automated Driving
Authors: Abu Jafar Md Muzahid, Xiaopeng Zhao, Zhenbo Wang
Date: 2024-12-11 00:00:00
Tasks: Decision Making

The capabilities of automated vehicles are advancing rapidly, yet achieving full autonomy remains a significant challenge, requiring ongoing human cognition in decision-making processes. Incorporating human cognition into control algorithms has become increasingly important, as researchers work to develop strategies that minimize conflicts between human drivers and AI systems. Despite notable progress, many challenges persist, underscoring the need for further innovation and refinement in this field. This review covers recent progress in human-vehicle interaction (HVI) and AI collaboration for vehicle control. First, we start by looking at how HVI has evolved, pointing out key developments and identifying persistent problems. Second, we discuss the existing techniques, including methods for integrating human intuition and cognition into decision-making processes and developing systems that can mimic human behavior to enable optimal driving strategies and achieve safer and more efficient transportation. This review aims to contribute to the development of more effective and adaptive automated driving systems by enhancing human-AI collaboration.
Data-Driven Assessment of Vehicle-to-Grid Capabilities in Supporting Grid During Emergencies: Case Study of Travis County, TX
Authors: Kelsey Nelson, Javad Mohammadi
Date: 2024-12-10 00:00:00

As extreme weather events become more common and threaten power grids, the continuing adoption of electric vehicles (EVs) introduces a growing opportunity for their use as a distributed energy storage resource. This energy storage can be used as backup generation through the use of vehicle-to-grid (V2G) technology, where electricity is sent back from EV batteries to the grid. With enough participation from EV owners, V2G can mitigate outages during grid emergencies. In order to investigate a practical application of V2G, this study leverages a vast array of real-world data, such as survey results on V2G participation willingness, historical outage data within ERCOT, current EV registrations, and demographic data. This data informs realistic emergency grid scenarios with V2G support using a synthetic transmission grid for Travis County. The results find that as EV ownership rises in the coming years, the simultaneous facilitation of bidirectional charging availability would allow for V2G to play a substantial role in preventing involuntary load shed as a result of emergencies like winter storms.
Fault Isolation for the Ink Deposition Process in High-End Industrial Printers
Authors: Casper van Peijpe, Farhad Ghanipoor, Youri de Loore, Pim Hacking, Nathan van de Wouw, Peyman Mohajerin Esfahani
Date: 2024-12-10 00:00:00
Tasks: Fault Detection

This paper presents a mathematical framework for modeling the dynamic effects of three fault categories and six fault variants in the ink channels of high-end industrial printers. It also introduces a hybrid approach that combines model-based and data-based methods to detect and isolate these faults effectively. A key challenge in these systems is that the same piezo device is used for actuation (generating ink droplets) and for sensing and, as a consequence, sensing is only available when there is no actuation. The proposed Fault Detection (FD) filter, based on the healthy model, uses the piezo self-sensing signal to generate a residual, while taking the above challenge into account. The system is flagged as faulty if the residual energy exceeds a threshold. Fault Isolation (FI) is achieved through linear regression or a k-nearest neighbors approach to identify the most likely fault category and variant. The resulting hybrid Fault Detection and Isolation (FDI) method overcomes traditional limitations of model-based methods by isolating different types of faults affecting the same entries (i.e., equations) in the ink channel dynamics. Moreover, it is shown to outperform purely data-driven methods in fault isolation, especially when data is scarce. Experimental validation demonstrates superior FDI performance compared to state-of-the-art methods.
Event-Triggered Memory Control for Interval Type-2 Fuzzy Heterogeneous Multi-Agent Systems
Authors: Sen Kong
Date: 2024-12-10 00:00:00

This study explores the design of a memory-based dynamic event-triggered mechanisms (DETM) scheme for heterogeneous multi-agent systems (MASs) characterized by interval type-2 Takagi-Sugeno (IT2 T-S) fuzzy models. To address the complex nonlinear uncertainties inherent in such systems, discrete IT2 T-S fuzzy models are employed to accurately capture system dynamics. In response to the limitations on communication resources and computational capabilities within MASs, this research introduces a distributed DETM approach based on a dynamic threshold method. This mechanism effectively minimizes unnecessary communication while maintaining robust performance. The proposed memory-based control strategy not only reduces the conservatism associated with controller design conditions but also enhances overall controller performance. Furthermore, leveraging a non-parallel distributed compensation (non-PDC) strategy, a novel derivation method is developed for controller design conditions that significantly decreases conservatism. This leads to sufficient conditions for the asymptotic stability of the closed-loop system. The designed distributed event-triggered controllers improve the overall performance of MASs, as evidenced by numerical simulations that validate the effectiveness of the proposed approach. Overall, these findings advance the state-of-the-art in control strategies for heterogeneous MASs, offering practical solutions for real-world applications where resource constraints are critical.
Little to lose: the case for a robust European green hydrogen strategy
Authors: Koen van Greevenbroek, Johannes Schmidt, Marianne Zeyringer, Alexander Horsch
Date: 2024-12-10 00:00:00

The EU targets 10 Mt of green hydrogen production by 2030, but has not committed to targets for 2040. Green hydrogen competes with carbon capture and storage, biomass and imports in reaching emissions reductions; earlier studies have demonstrated the great uncertainty in future cost-optimal development of green hydrogen. In spite of this, we show that Europe risks little by setting green hydrogen production targets at around 25 Mt by 2040. Employing an extensive scenario analysis combined with novel near-optimal techniques, we find that this target results in systems that are within 10% of cost-optimal in most considered scenarios. Setting concrete targets is important in order to resolve significant uncertainty which hampers investments. Targeting green hydrogen reduces the dependence on carbon capture and storage and green fuel imports, making for a more robust European climate strategy.
Disturbance Observer-Parameterized Control Barrier Function with Adaptive Safety Bounds
Authors: Ziqi Yang, Lihua Xie
Date: 2024-12-10 00:00:00

This letter presents a nonlinear disturbance observer-parameterized control barrier function (DOp-CBF) designed for a robust safety control system under external disturbances. This framework emphasizes that the safety bounds are relevant to the disturbances, acknowledging the critical impact of disturbances on system safety. This work incorporates a disturbance observer (DO) as an adaptive mechanism of the safety bounds design. Instead of considering the worst-case scenario, the safety bounds are dynamically adjusted using DO. The forward invariance of the proposed method regardless of the observer error is ensured, and the corresponding optimal control formulation is presented. The performance of the proposed method is demonstrated through simulations of a cruise control problem under varying road grades. The influence of road grade on the safe distance between vehicles is analyzed and managed using a DO. The results demonstrate the advantages of this approach in maintaining safety and improving system performance under disturbances.
CEEMS: A Resource Manager Agnostic Energy and Emissions Monitoring Stack
Authors: Mahendra Paipuri
Date: 2024-12-10 00:00:00
Tasks: CPU, GPU

With the rapid acceleration of ML/AI research in the last couple of years, the energy consumption of the Information and Communication Technology (ICT) domain has rapidly increased. As a major part of this energy consumption is due to users' workloads, it is evident that users need to be aware of the energy footprint of their applications. Compute Energy and Emissions Monitoring Stack (CEEMS) has been designed to address this issue. CEEMS can report energy consumption and equivalent emissions of user workloads in real time for HPC and cloud platforms alike. Besides CPU energy usage, it supports reporting energy usage of workloads on NVIDIA and AMD GPU accelerators. CEEMS has been built around the prominent open-source tools in the observability eco-system like Prometheus and Grafana. CEEMS has been designed to be extensible and it allows the Data Center (DC) operators to easily define the energy estimation rules of user workloads based on the underlying hardware. This paper explains the architectural overview of CEEMS, data sources that are used to measure energy usage and estimate equivalent emissions and potential use cases of CEEMS from operator and user perspectives. Finally, the paper will conclude by describing how CEEMS deployment on the Jean-Zay supercomputing platform is capable of monitoring more than 1400 nodes that have a daily job churn rate of around 20k jobs.
Learning k-Inductive Control Barrier Certificates for Unknown Nonlinear Dynamics Beyond Polynomials
Authors: Ben Wooding, Abolfazl Lavaei
Date: 2024-12-10 00:00:00
Tasks: LEMMA

This work is concerned with synthesizing safety controllers for discrete-time nonlinear systems beyond polynomials with unknown mathematical models using the notion of k-inductive control barrier certificates (k-CBCs). Conventional CBC conditions (with k=1) for ensuring safety over dynamical systems are often restrictive, as they require the CBCs to be non-increasing at every time step. Inspired by the success of k-induction in software verification, k-CBCs relax this requirement by allowing the barrier function to be non-increasing over k steps, while permitting k-1 (one-step) increases, each up to a threshold epsilon. This relaxation enhances the likelihood of finding feasible k-CBCs while providing safety guarantees across the dynamical systems. Despite showing promise, existing approaches for constructing k-CBCs often rely on precise mathematical knowledge of system dynamics, which is frequently unavailable in practical scenarios. In this work, we address the case where the underlying dynamics are unknown, a common occurrence in real-world applications, and employ the concept of persistency of excitation, grounded in Willems et al.'s fundamental lemma. This result implies that input-output data from a single trajectory can capture the behavior of an unknown system, provided the collected data fulfills a specific rank condition. We employ sum-of-squares (SOS) programming to synthesize the k-CBC as well as the safety controller directly from data while ensuring the safe behavior of the unknown system. The efficacy of our approach is demonstrated through a set of physical benchmarks with unknown dynamics, including a DC motor, an RLC circuit, a nonlinear nonpolynomial car, and a nonlinear polynomial Lorenz attractor.
A Distributed Deep Koopman Learning Algorithm for Control
Authors: Wenjian Hao, Zehui Lu, Devesh Upadhyay, Shaoshuai Mou
Date: 2024-12-10 00:00:00
Tasks: Model Predictive Control

This paper proposes a distributed data-driven framework to address the challenge of dynamics learning from a large amount of training data for optimal control purposes, named distributed deep Koopman learning for control (DDKC). Suppose a system states-inputs trajectory and a multi-agent system (MAS), the key idea of DDKC is to assign each agent in MAS an offline partial trajectory, and each agent approximates the unknown dynamics linearly relying on the deep neural network (DNN) and Koopman operator theory by communicating information with other agents to reach a consensus of the approximated dynamics for all agents in MAS. Simulations on a surface vehicle first show that the proposed method achieves the consensus in terms of the learned dynamics and the learned dynamics from each agent can achieve reasonably small estimation errors over the testing data. Furthermore, simulations in combination with model predictive control (MPC) to drive the surface vehicle for goal-tracking and station-keeping tasks demonstrate the learned dynamics from DDKC are precise enough to be used for the optimal control design.
Microcontroller-Driven MPPT System for Enhanced Photovoltaic Efficiency: An Experimental Approach in Nepal
Authors: Diwakar Khadka, Satish Adhikari, Atit Pokharel, Sandeep Marasinee, Aayush Pathak
Date: 2024-12-09 00:00:00
Tasks: Point Tracking

Solar energy utilization in places like Nepal, is often obstructed by unpredicted environmental factors and existing technological barriers. The challenges encountered often result in fluctuating energy outputs, hindering the transition to greener energy solutions. To tackle these issues, this study introduces a custom-designed Maximum Power Point Tracking (MPPT) controller, seamlessly incorporated into a microcontroller-based battery charging system. This approach seeks to enhance the efficiency of photovoltaic (PV) systems, aligning with the global shift towards renewables. The research's primary objective is to enhance PV module power yield employing MPPT techniques, thereby reducing dependency on non-renewable energy sources. Key goals include real-time MPP tracking for optimal power extraction from PV modules and the integration of a real-time monitoring mechanism for PV and battery states. Leveraging a coordinated interplay of sensors measuring temperature, voltage, and current, vital metrics are fed to the microcontroller. This, in turn, generates a precise Pulse Width Modulation (PWM) signal, fine-tuning the voltage regulation of the buck-boost converter Metal Oxide Semiconductor Field Effect Transistor (MOSFET) for optimal operation. The adopted approach emphasizes monitoring environmental metrics, overseeing power outputs, and generating PWM signals to adeptly manage the buck-boost converter MOSFET voltage. Concurrently, data is transmitted hourly to a cloud platform, facilitating real-time monitoring capabilities showcasing the IoT application. As a result of these integrations, an efficiency improvement of approximately 37.28% was observed. In essence, this research underscores the profound impact of merging advanced technologies within the renewable energy sector, offering a robust blueprint for enhancing energy stability and productivity.