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AIAA SciTech Forum and Exposition, 2023

作者： Echigo, Kazuya Hayner, Christopher R. Mittal, Avi Açıkmeşe, Behçet Sarsılmaz, Selahattin Burak Harris, Matthew Department of Aeronautics and Astronautics University of Washington SeattleWA98195 United States Department of Electrical and Computer Engineering Utah State University LoganUT84322 United States Department of Mechanical and Aerospace Engineering Utah State University LoganUT United States

ISBN: (数字)9781624106996

ISBN: (纸本)9781624106996

This paper presents a convex optimization-based trajectory planner for close proximity relative-orbit operations using electric propulsion (EP). We target an EP system where the magnitude of thrust should be quantized. Traditional solution methods dealing with this input quantization-type constraint require solving computationally expensive mixed-integer programs. We propose an objective function that promotes quantization for the magnitude of the control input which, when combined with lossless convexifacation, results in a far more computationally tractable Second Order Cone Program (SOCP). A convex optimization problem minimizing this objective function is then formulated while satisfying a modified form of linearized relative orbital element (LROE) dynamics, control constraints, and boundary conditions. Additionally, we introduce a fuel sub-optimal constraint and propose a planner that relaxes the constraint recursively until a quantized solution is achieved. We demonstrate the capability of the proposed objective function through several numerical studies and provide a heuristic for achieving a quantized thrust profile. © 2023, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

关键词： Electric propulsion

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Safe Reference Tracking and Collision Avoidance for Taxiing Aircraft Using an MPC-CBF Framework

arXiv

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arXiv 2024年

作者： Butler, Brooks A. Cabrera, Zarif Nguyen, Andy Paré, Philip E. The Department of Electrical Engineering and Computer Science The University of California Irvine United States The Department of Electrical Engineering and Computer Science Howard University United States The Department of Mechanical Engineering Augustana College United States The Elmore Family School of Electrical and Computer Engineering Purdue University United States

In this paper, we develop a framework for the automatic taxiing of aircraft between hangar and take-off given a graph-based model of an airport. We implement a high-level path-planning algorithm that models taxiway intersections as nodes in an undirected graph, algorithmically constructs a directed graph according to the physical limitations of the aircraft, and finds the shortest valid taxi path through the directed graph using Dijkstra’s algorithm. We then use this shortest path to construct a reference trajectory for the aircraft to follow that considers the turning capabilities of a given aircraft. Using high-order control barrier functions (HOCBFs), we construct safety conditions for multi-obstacle avoidance and safe reference tracking for simple 2D unicycle dynamics with acceleration control inputs. We then use these safety conditions to design an MPC-CBF framework that tracks the reference trajectory while adhering to the safety constraints. We compare the performance of our MPC-CBF controller with a PID-CBF control method via simulations. © 2024, CC BY.

关键词： Aircraft accidents

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Probabilistic Uncertainty Quantification of Prediction Models with Application to Visual Localization

Probabilistic Uncertainty Quantification of Prediction Model...

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IEEE International Conference on Robotics and Automation (ICRA)

作者： Junan Chen Josephine Monica Wei-Lun Chao Mark Campbell Mechanical and Aerospace Engineering Department Cornell University Department of Computer Science and Engineering Ohio State University

The uncertainty quantification of prediction models (e.g., neural networks) is crucial for their adoption in many robotics applications. This is arguably as important as making accurate predictions, especially for safety-critical applications such as self-driving cars. This paper proposes our approach to uncertainty quantification in the context of visual localization for autonomous driving, where we predict locations from images. Our proposed framework estimates probabilistic uncertainty by creating a sensor error model that maps an internal output of the prediction model to the uncertainty. The sensor error model is created using multiple image databases of visual localization, each with ground-truth location. We demonstrate the accuracy of our uncertainty prediction framework using the Ithaca365 dataset, which includes variations in lighting, weather (sunny, snowy, night), and alignment errors between databases. We analyze both the predicted uncertainty and its incorporation into a Kalman-based localization filter. Our results show that prediction error variations increase with poor weather and lighting condition, leading to greater uncertainty and outliers, which can be predicted by our proposed uncertainty model. Additionally, our probabilistic error model enables the filter to remove ad hoc sensor gating, as the uncertainty automatically adjusts the model to the input data.

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How to deal with glare for improved perception of Autonomous Vehicles

arXiv

引用

arXiv 2024年

作者： Alam, Muhammad Z. Kaleem, Zeeshan Kelouwani, Sousso Department of Computer science Brandon University Canada Department of Electrical and Computer Engineering COMSATS University Pakistan Department of Mechanical Engineering UQTR Canada

Vision sensors are versatile and can capture a wide range of visual cues, such as color, texture, shape, and depth. This versatility, along with the relatively inexpensive availability of machine vision cameras, played an important role in adopting vision-based environment perception systems in autonomous vehicles (AVs). However, vision-based perception systems can be easily affected by glare in the presence of a bright source of light, such as the sun or the headlights of the oncoming vehicle at night or simply by light reflecting off snow or ice-covered surfaces;scenarios encountered frequently during driving. In this paper, we investigate various glare reduction techniques, including the proposed saturated pixel-aware glare reduction technique for improved performance of the computer vision (CV) tasks employed by the perception layer of AVs. We evaluate these glare reduction methods based on various performance metrics of the CV algorithms used by the perception layer. Specifically, we considered object detection, object recognition, object tracking, depth estimation, and lane detection which are crucial for autonomous driving. The experimental findings validate the efficacy of the proposed glare reduction approach, showcasing enhanced performance across diverse perception tasks and remarkable resilience against varying levels of glare. Copyright © 2024, The Authors. All rights reserved.

关键词： Autonomous vehicles

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Design of Microscale Magnetic Controls for Magnetic-Field Driven Actuation

Design of Microscale Magnetic Controls for Magnetic-Field Dr...

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2023 IEEE International Magnetic Conference - Short Papers, INTERMAG Short Papers 2023

作者： Cestarollo, Ludovico Cantu, Rodolfo Srinivasan, Karthik El-Ghazaly, Amal Cornell University Department of Materials Science and Engineering IthacaNY14853 United States The University of Texas at Austin Department of Mechanical Engineering AustinTX78712 United States Cornell University Department of Electrical and Computer Engineering IthacaNY14853 United States

ISBN: (纸本)9798350338362

Magnetic actuators require reproducible, small-scale approaches for controlling the magnetic field gradient and direction used to drive the actuation. Here a system of two control magnets is designed to generate the local magnetic fields that are required to actuate a magnetic system and elicit microscale, local deflections. The two control magnets are engineered to have magnetizations preferentially pointing along two orthogonal axes, leading to the coupling of the magnetic flux densities between them and the generation of a field (and gradient) localized with micrometer resolution. To demonstrate the ability of this field to exert an actuation force on a magnetic material, a system composed of the two control magnets and a microscale magnetic beam/cantilever is designed and simulated. © 2023 IEEE.

关键词： Magnetic anisotropy

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Leveraging Tethers for Distributed Formation Control of Simple Robots

Leveraging Tethers for Distributed Formation Control of Simp...

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IEEE International Conference on Robotics and Automation (ICRA)

作者： Sadie Cutler Kirstin Petersen Sibley School of Mechanical and Aerospace Engineering Cornell University Ithaca NY USA School of Electrical and Computer Engineering Cornell University Ithaca NY USA

ISBN: (数字)9798350384574

ISBN: (纸本)9798350384581

Tethers have great potential in multi-robot systems from enabling retrieval of deployed robots and facilitating power transfer, to use by the robots as a net or partition. In this paper, we show in simulation that tethers can also be used to do distributed formation control on very simple robots. Specifically, our simulated agents are connected in series by un-actuated, flexible, fixed-length tethers and use tether angle and strain, in conjunction with the physical constraints of the tethers, to adjust their position with respect to their neighbors. This presents a significant simplification over traditional formation control which, at a minimum, requires exteroceptive sensors to perceive bearing and/or distance to nearby agents. We present and evaluate an algorithm on a large set of transitions between formations with 5 agents and an example transition with 35 agents. The convergence time grows with the number of agents, however, the memory and computation time per agent remain constant. Future work will investigate the ability to use tethers and strain for reactive behaviors and more diverse tasks.

关键词： Encapsulation Robot kinematics Prediction algorithms Robot sensing systems Birds Formation control Sensors

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Parameterized Fast and Safe Tracking (FaSTrack) using DeepReach

arXiv

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arXiv 2024年

作者： Jeong, Hyun Joe Gong, Zheng Bansal, Somil Herbert, Sylvia Department of Mechanical and Aerospace Engineering University of California San Diego United States Department of Electrical and Computer Engineering University of Southern California United States

Fast and Safe Tracking (FaSTrack, Herbert* et al. (2017)) is a modular framework that provides safety guarantees while planning and executing trajectories in real time via value functions of Hamilton-Jacobi (HJ) reachability. These value functions are computed through dynamic programming, which is notorious for being computationally inefficient. Moreover, the resulting trajectory does not adapt online to the environment, such as sudden disturbances or obstacles. DeepReach (Bansal and Tomlin (2021)) is a scalable deep learning method to HJ reachability that allows parameterization of states, which opens up possibilities for online adaptation to various controls and disturbances. In this paper, we propose Parametric FaSTrack, which uses DeepReach to approximate a value function that parameterizes the control bounds of the planning model. The new framework can smoothly trade off between the navigation speed and the tracking error (therefore maneuverability) while guaranteeing obstacle avoidance in a priori unknown environments. We demonstrate our method through two examples and a benchmark comparison with existing methods, showing the safety, efficiency, and faster solution times of the framework. Copyright © 2024, The Authors. All rights reserved.

关键词： Dynamic programming

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Evaluating Dry Electrodes and Bioinstrumentation for Wearable Arm ECG Acquisition

Evaluating Dry Electrodes and Bioinstrumentation for Wearabl...

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2024 International Conference on the Challenges, Opportunities, Innovations and Applications in Electronic Textiles, E-Textiles 2024

作者： Veeturi, Suparna Ravichandran, Vignesh Cerullo, Alex Chomal, Shubham Shahriari, Yalda Carreiro, Stephanie Venkatasubramanian, Krishna Mankodiya, Kunal Solanki, Dhaval University of Rhode Island Department of Electrical Computer and Biomedical Engineering United States University of Massachusetts Chan Medical School Department of Emergency Medicine United States University of Rhode Island Department of Mechanical Industrial and Systems Engineering KingstonRI United States University of Rhode Island Department of Computer Science and Statistics United States

ISBN: (纸本)9783000804298

Arm-based electrocardiogram (ECG) offers a more comfortable and user-friendly alternative to traditional chest ECG for wearable cardiac monitoring in daily health applications. However, arm ECG faces challenges such as capturing extremely low-amplitude signals in the microvolt range and significant electromyogram (EMG) noise contamination. The aim of this study was to evaluate the performance of dry electrodes for arm and chest ECG monitoring using gold standard BIOPAC and proposed mDAQ systems. This study consisted of two phases. In Phase 1, we evaluated different dry electrode materials, including silver knit fabric and gold-plated electrodes, with six healthy adult participants (N = males and N =3 females) having upper arm circumference ranging from 27 to 42 cm. We used a BIOPAC system as a gold standard to collect arm ECG, upper arm EMG, and reference chest ECG during standardized movement tasks. Results showed that silver knit electrodes demonstrated superior QRS energy (0.705 ± 0.151), surpassing chest gel floating ECG QRS energy (0.328 ± 0.026), with lower EMG interference across movement conditions. In Phase 2, we developed a bioinstrumentation system (mDAQ) optimized for dry electrodes, demonstrating reliable ECG acquisition in both chest Lead I and arm configurations. -We validated our bioinstrumentation with sixteen healthy adult participants (N = 8 male and N = female. The mDAQ system maintained high signal consistency with a skewness effect size of 0.963 and showed a mean heart rate bias of only -1.842 bpm compared to the BIOPAC system, confirming its viability for wearable ECG monitoring applications. © 2024 Fraunhofer IZM.

关键词： Gold plating

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A Predictive Gradient Based LMS Filter for Micro-Opto-Electro-mechanical Systems

A Predictive Gradient Based LMS Filter for Micro-Opto-Electr...

引用

7th International Conference on Electronics Technology, ICET 2024

作者： Wang, Fumin Chai, Guo Tan, Yonghong Dong, Ruili Tan, Qingyuan Shanghai Normal University College of Information Electrical and Mechanical Engineering Shanghai China Shanghai Normal University College of Mathematics and Physics Shanghai China Donghua University School of Informstion Science and Technology Shanghai China University of Windsor Dept. of Electrical and Computer Engineering WindsorON Canada

ISBN: (纸本)9798350363951

In order to estimate the state of MEMS micromirror in the environment with random noise, in this paper, a so-called predictive gradient based least mean square (PG BLMS) filtering method is proposed. In this filtering method, a stochastic state space model with hysteresis is developed to describe characteristic of MEMS micromirror disturbed by random noise. Then, the PGBLMS filter is developed using the established model to eliminate the influence of random noise. Subsequently, the proposed filtering method is applied to the state estimation of an electromagnetic scanning micromirror disturbed by random noise. © 2024 IEEE.

关键词： Stochastic systems

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Design and Evaluation of a Low-profile Haptic Interface Based on Surface electrical Nerve Stimulation 1

Design and Evaluation of a Low-profile Haptic Interface Base...

引用

1st IEEE Conference on Telepresence, Telepresence 2024

作者： Jakes, Rachel S. Mesias, Luis Santos, Veronica J. Fu, Michael J. Tyler, Dustin J. Cwru Dept. of Biomedical Engineering United States Dept. of Mechanical and Aerospace Engineering United States United States Cwru Dept. of Electrical Computer and Systems Engineering United States The MetroHealth System Dept. of Physical Medicine & Rehabilitation United States Advanced Platform Technology Center Dept. of Va Northeast Ohio Healthcare System United States

ISBN: (纸本)9798331528249

Haptic feedback in telepresence applications is vital for remote task performance and object manipulation. To maximize telepresence capabilities, haptic systems need to be integrated with immersive telepresence interfaces such as virtual reality, which offer benefits such as improved spatial awareness and operator mobility. Compatibility with the mobility of these systems and their built-in optical hand tracking require low-profile wearable interfaces. Further, for full functional benefits, haptic systems must be able to elicit spatially congruent sensation without impeding operator movement and physical object interactions. In this paper, we describe the design of a lightweight, compact, and adaptable surface electrical nerve stimulation-based haptic interface. We demonstrate its capacity to consistently generate spatially congruent sensation on the all five fingertips without occlusion, as well as its compatibility with headset-based optical hand tracking. © 2024 IEEE.

关键词： Haptic interfaces

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