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Model Predictive Control of a Direct Current Motor Utilizing Lookup Tables

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Model Predictive Control of a Direct Current Motor Utilizing...

International Conference on Power Drives systems (ICPDS)

作者： Alecksey Anuchin Andrei Bogdanov Galina Demidova Dmitrii Savkin Ksenya Fedorova Maria Gulyaeva Moscow Power Engineering Institute Moscow Russia Faculty of Control System and Robotics ITMO University Saint-Petersburg Russia

ISBN: (数字)9781728165387

ISBN: (纸本)9781728165394

The problem of unpredictable acoustic behaviour of the finite control set model predictive control (MPC) can be solved in continuous control set MPC. However, continuous control set MPC usually requires huge computation efforts or analytical solution of the non-linear equations of the motor, which is not always possible. This paper considers the option of precalculation of all control commands for each combination of the input variables. This approach is applicable for the drives with limited number of state variables, such as direct current motor or switched reluctance machine. An example of the control system of direct current motor with torque stabilization and minimization of the ohmic losses was implemented using simulation model. The 4-dimensional lookup table was used for armature current control and 2-dimensional lookup table was used for field winding control. The simulation results show rapid torque stabilization together with losses minimization.

关键词： Torque Memory management Switches DC motors Control systems Minimization Predictive control

Machine Vision-Based Assessment of Fall Color Changes in Apple Leaves and its Relationship with Nitrogen Concentration

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arXiv 2024年

作者： Paudel, Achyut Brown, Jostan Upadhyaya, Priyanka Asad, Atif Bilal Kshetri, Safal Davidson, Joseph R. Grimm, Cindy Thompson, Ashley Sallato, Bernardita Whiting, Matthew D. Karkee, Manoj Biological Systems Engineering Department Center for Precision and Automated Agricultural System Washington State University ProsserWA99350 United States Collaborative Robotics and Intelligent Systems Institute Oregon State University CorvallisOR97331 United States Mid-Columbia Agricultural Research and Extension Center Oregon State University Hood RiverOR97031 United States Irrigated Agriculture Research and Extension Center Washington State University ProsserWA99350 United States Department of Horticulture Washington State University ProsserWA99350 United States

Apple(Malus domestica Borkh.) trees are deciduous, shedding leaves each year. This process is preceded by a gradual change in leaf color from green to yellow as chlorophyll is degraded prior to abscission. The initiation and rate of this color change are affected by many factors including leaf nitrogen (N) concentration. We predict that leaf color during this transition may be indicative of the nitrogen status of apple trees. This study assesses a machine vision-based system for quantifying the change in leaf color and its correlation with leaf nitrogen content. An image dataset was collected in color and 3D over five weeks in the fall of 2021 and 2023 at a commercial orchard using a ground vehicle-based stereovision sensor. Trees in the foreground were segmented from the point cloud using color and depth thresholding methods. Then, to estimate the proportion of yellow leaves per canopy, the color information of the segmented canopy area was quantified using a custom-defined metric, "yellowness index" (a normalized ratio of yellow to green foliage in the tree) that varied from -1 to +1 (-1 being completely green and +1 being completely yellow). Both K-means-based methods and gradient boosting methods were used to estimate the yellowness index. The gradient boosting based method proposed in this study was better than the K-means-based method (both in terms of computational time and accuracy), achieving an R2 of 0.72 in estimating the yellowness index. The metric was able to capture the gradual color transition from green to yellow over the study duration. Trees with lower leaf nitrogen showed the color transition to yellow earlier than the trees with higher nitrogen. The onset of color transition during both years occurred during the 29th week post-full bloom (October 22 in 2021 and Nov 10 in 2023). This critical timing could be used for conducting nitrogen status analysis on apple trees using machine vision, enabling more precise and timely assessment of nutrient le

关键词： Fruits

A Novel Path Planning Approach with Bidirectional A* Algorithm Based on Road Characteristics

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A Novel Path Planning Approach with Bidirectional A* Algorit...

International Conference on Mechatronics and Machine Vision in Practice (M2VIP)

作者： Weihua Li Bowen Chen Pengpeng Li Xuewen Geng Jianfeng Wang State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China School of Automotive Engineering Harbin Institute of Technology-Weihai Weihai China SGCC Smart Energy and Electric Transportation Technology Innovation Center (Suzhou) Co.Ltd. Suzhou China

ISBN: (纸本)9781665431545

The global path planning of a traditional A* algorithm is investigated to obtain the shortest path, which considers only the straight-line distance between grids without considering the effects of road slope and road resistance on the path distance and the energy consumption for ground vehicles. The heuristic function of shortest path based on road slope and the heuristic function of minimum energy consumption based on road resistance coefficient are respectively developed in this paper. Combining the two improvements, a novel comprehensive heuristic function is proposed in this paper. Through the distribution of weight coefficients between the shortest path and the minimum energy consumption, one more reasonable path can be obtained. In addition, a bidirectional A* search algorithm is also applied. The case studies validate that the improved A* search algorithm in this paper can generate a more reasonable path considering the distance and the energy consumption.

关键词： Resistance Energy consumption Mechatronics Roads Heuristic algorithms Machine vision Focusing

Scientific Exploration of Challenging Planetary Analog Environments with a Team of Legged Robots

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arXiv 2023年

作者： Arm, Philip Waibel, Gabriel Preisig, Jan Tuna, Turcan Zhou, Ruyi Bickel, Valentin Ligeza, Gabriela Miki, Takahiro Kehl, Florian Kolvenbach, Hendrik Hutter, Marco Robotic Systems Lab ETH Zurich Zurich Switzerland State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China Laboratory of Hydraulics Hydrology and Glaciology ETH Zurich Zurich Switzerland Center for Space and Habitability University of Bern Bern Switzerland Department of Environmental Sciences University of Basel Basel Switzerland University of Zurich Dübendorf Switzerland Center for Theoretical Astrophysics and Cosmology University of Zurich Zurich Switzerland Institute of Medical Engineering Space Biology Group Lucerne University of Applied Sciences and Art Hergiswil Switzerland

The interest in exploring planetary bodies for scientific investigation and in-situ resource utilization is ever-rising. Yet, many sites of interest are inaccessible to state-of-the-art planetary exploration robots because of the robots’ inability to traverse steep slopes, unstructured terrain, and loose soil. Additionally, current single-robot approaches only allow a limited exploration speed and a single set of skills. Here, we present a team of legged robots with complementary skills for exploration missions in challenging planetary analog environments. We equipped the robots with an efficient locomotion controller, a mapping pipeline for online and post-mission visualization, instance segmentation to highlight scientific targets, and scientific instruments for remote and in-situ investigation. Furthermore, we integrated a robotic arm on one of the robots to enable high-precision measurements. Legged robots can swiftly navigate representative terrains, such as granular slopes beyond 25 degrees, loose soil, and unstructured terrain, highlighting their advantages compared to wheeled rover systems. We successfully verified the approach in analog deployments at the BeyondGravity ExoMars rover testbed, in a quarry in Switzerland, and at the Space Resources Challenge in Luxembourg. Our results show that a team of legged robots with advanced locomotion, perception, and measurement skills, as well as task-level autonomy, can conduct successful, effective missions in a short time. Our approach enables the scientific exploration of planetary target sites that are currently out of human and robotic reach. Copyright © 2023, The Authors. All rights reserved.

关键词： Robots

Research on impedance control of flexible joint space manipulator on-orbit servicing

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Research on impedance control of flexible joint space manipu...

2019 IEEE International Conference on robotics and Biomimetics, ROBIO 2019

作者： Liu, Dongyu Liu, Hong Liu, Yechao Li, Zhiqi China Academy of Space Technology Institute of Manned Spacecraft System Engineering Beijing China Harbin Institute of Technology State Key Laboratory of Robotics and System Harbin Heilongjiang Province China

ISBN: (纸本)9781728163215

In this paper, the positional accuracy and contact force index requirements of the manipulator are analyzed according to the tolerance index of the space manipulator screwing. An position-based in Cartesian space impedance control strategy based on friction identification and compensation is proposed. By using joint friction torque compensation to improve the system control precision and setting the desired Cartesian position of the manipulator end point to control the contact force, this strategy solves the contradiction between the positional accuracy index and the contact force index requirement of manipulator during contact operating. The control algorithm is designed based on the system dynamics model, and the stability analysis of the control algorithm is given. The correctness of the control strategy is verified by simulation and on-orbit implementation. China's space manipulator has successfully completed the actual on-orbit servicing mission based on impedance control for the first time. © 2019 IEEE.

关键词： Friction

Domain generalization for document authentication against practical recapturing attacks

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arXiv 2021年

作者： Chen, Changsheng Zhang, Shuzheng Lan, Fengbo Huang, Jiwu The Guangdong Key Laboratory of Intelligent Information Processing Shenzhen Key Laboratory of Media Security National Engineering Laboratory for Big Data System Computing Technology College of Electronics and Information Engineering Shenzhen University Shenzhen China Shenzhen Institute of Artificial Intelligence and Robotics for Society China

Recapturing attack can be employed as a simple but effective anti-forensic tool for digital document images. Inspired by the document inspection process that compares a questioned document against a reference sample, we proposed a document recapture detection scheme by employing Siamese network to compare and extract distinct features in a recapture document image. The proposed algorithm takes advantages of both metric learning and image forensic techniques. Instead of adopting Euclidean distance-based loss function, we integrate the forensic similarity function with a triplet loss and a normalized softmax loss. After training with the proposed triplet selection strategy, the resulting feature embedding clusters the genuine samples near the reference while pushes the recaptured samples apart. In the experiment, we consider practical domain generalization problems, such as the variations in printing/imaging devices, substrates, recapturing channels, and document types. To evaluate the robustness of different approaches, we benchmark some popular off-the-shelf machine learning-based approaches, a state-of-the-art document image detection scheme, and the proposed schemes with different network backbones under various experimental protocols. Experimental results show that the proposed schemes with different network backbones have consistently outperformed the state-of-the-art approaches under different experimental settings. Specifically, under the most challenging scenario in our experiment, i.e., evaluation across different types of documents that produced by different devices, we have achieved less than 5.00% APCER (Attack Presentation Classification Error Rate) and 5.56% BPCER (Bona Fide Presentation Classification Error Rate) by the proposed network with ResNeXt101 backbone at 5% BPCER decision *** Codes 94A08 Copyright © 2021, The Authors. All rights reserved.

关键词： Feature extraction

Deep learning-based forgery attack on document images

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arXiv 2021年

作者： Zhao, Lin Chen, Changsheng Huang, Jiwu the Guangdong Key Laboratory of Intelligent Information Processing Shenzhen Key Laboratory of Media Security National Engineering Laboratory for Big Data System Computing Technology College of Electronics and Information Engineering Shenzhen University Shenzhen China Shenzhen Institute of Artificial Intelligence and Robotics for Society China

With the ongoing popularization of online services, the digital document images have been used in various applications. Meanwhile, there have emerged some deep learning-based text editing algorithms which alter the textual information of an image in an end-to-end fashion. In this work, we present a low-cost document forgery algorithm by the existing deep learning-based technologies to edit practical document images. To achieve this goal, the limitations of existing text editing algorithms towards complicated characters and complex background are addressed by a set of network design strategies. First, the unnecessary confusion in the supervision data is avoided by disentangling the textual and background information in the source images. Second, to capture the structure of some complicated components, the text skeleton is provided as auxiliary information and the continuity in texture is considered explicitly in the loss function. Third, the forgery traces induced by the text editing operation are mitigated by some post-processing operations which consider the distortions from the print-and-scan channel. Quantitative comparisons of the proposed method and the exiting approach have shown the advantages of our design by reducing the about 2/3 reconstruction error measured in MSE, improving reconstruction quality measured in PSNR and in SSIM by 4 dB and 0.21, respectively. Qualitative experiments have confirmed that the reconstruction results of the proposed method are visually better than the existing approach in both complicated characters and complex texture. More importantly, we have demonstrated the performance of the proposed document forgery algorithm under a practical scenario where an attacker is able to alter the textual information in an identity document using only one sample in the target domain. The forged-and-recaptured samples created by the proposed text editing attack and recapturing operation have successfully fooled some existing document authenticat

关键词： Textures

Assessing the robustness of an optimization method for estimating muscle activity during gait: Preliminary findings

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Gait & Posture 2024年 113卷 135-135页

作者： Gheorghe Lisca Kim Kristin Peper Adam Park Thomas Grauschopf Veit Senner Sami Haddadin TUM School of Engineering and Design Associate Professorship of Sport Equipment and Sport Materials Munich Germany Audi Konfuzius-Institut Ingolstadt Microlab Ingolstadt Germany Technische Hochschule Ingolstadt Informatik Ingolstadt Germany Technical University of Munich Munich Institute of Robotics and Machine Intelligence- Chair of Robotics and System Intelligence Munich Germany

Tunable unidirectional compact acoustic amplifier via space-time modulated membranes

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Physical Review B 2020年第2期102卷 024309-024309页

作者： Xiaohui Zhu Junfei Li Chen Shen Guangyu Zhang Steven A. Cummer Longqiu Li State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin Heilongjiang 150001 China Department of Electrical and Computer Engineering Duke University Durham North Carolina 27708 USA

Space-time modulation has recently attracted considerable attention as it enables new possibilities in wave manipulation and control. Here we propose a tunable unidirectional acoustic amplifier based on a space-time modulated membrane system. The transfer matrix method is applied to design this system and optimize the modulation parameters for the realization of unidirectional amplification. Efficient one-way amplification of acoustic waves is demonstrated theoretically and numerically within a frequency range from 2260 to 2520 Hz, with overall dimension being less than 1/3 of the corresponding wavelength. Across this operation band, the amplification factor in the positive direction varies smoothly from 3.0 to 5.8, while the transmitted wave energy in the negative direction does not change significantly. Our work identifies a feasible approach to realize a tunable unidirectional acoustic amplifier via space-time modulated membranes, which offers a design platform for a number of applications in sensing, imaging, and communication.

关键词： Acoustic metamaterials Acoustic wave phenomena Sound waves