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On-Line Conference (ONCON), Industrial Electronics Society Annual

作者： Zhiren Chen Ziyu Qiu Nuo Chen the Department of Mechanical & Industrial Engineering University of Toronto Toronto Canada Faculty of Computer Science Dalhousie University Halifax Canada Department of Mechanical Engineering Advanced Control and Mechatronics Lab Dalhousie University Halifax Canada

This project developed a novel attention algorithm for multi-stack bidirectional encoder-decoder RNN (including GRU and LSTM) sequence-to-sequence models, particularly for language translation tasks. The attention mechanism utilizes matrix rearranging and multiplication to compute the significance of the vectors in the encoder output to the vectors in the current decoder hidden states when predicting each word. Our approach achieved 98% of the performance of fine-tuned pretrained T5-small, with 30% to 50% fewer parameters depending on vocabulary size, making our model an ideal choice in cases of single-processor training, low processor resource, limited memory, small dataset, or tasks not supported by pretrained transformers.

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Experimental Study on the Influence of Surface Carbon Content on Crack Initiation for 20Cr2Ni4A Steel 152nd

Experimental Study on the Influence of Surface Carbon Conten...

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152nd Annual Meeting and Exhibition of The Minerals, Metals and Materials Society, TMS 2023

作者： Zhang, Yingtao Gong, Benxiang Guo, Yunpeng Wang, Gang Ji, Xiulin College of Mechanical and Electrical Engineering Hohai University Changzhou213022 China Inner Mongolia Fist Machinery Group Co. Ltd. Inner Mongolia Baotou014030 China Beijing Key Lab of Precision/Ultra-Precision Manufacturing Equipments and Control Tsinghua University Beijing100084 China Department of Mechatronics Engineering Shantou University Shantou515063 China

ISBN: (纸本)9783031225239

20Cr2Ni4A steel is a kind of low-carbon steel mainly used in manufacturing heavy-duty transmission gears. The carburizing and quenching process is a common strengthening method for gears to get the fine mechanical properties. For the reason of quenching deformation, grinding is used to improve tooth surface accuracy, leading to uneven distribution of surface carbon concentration. In this paper, the different carburizing processes are applied for the 20Cr2Ni4A samples. Different surface carbon content is obtained by grinding with different depths. Three-point bending fatigue test is conducted to study the relationship between crack initiation and surface carbon concentration. The crack initiation and propagation process is monitored by industrial cameras and strain gauges. The number of cycles of crack initiation is positively correlated with the surface carbon content within the range of 1%. And the carbide particles are the main fatigue source. © 2023, The Minerals, Metals & Materials Society.

关键词： Crack initiation

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Cooperative localization of UAV based on information synchronization

Cooperative localization of UAV based on information synchro...

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International Conference on mechatronics and Automation

作者： Qu, Yaohong Zhang, Youmin Zhou, Qingli School of Automation Northwestern Polytechnical University Xi'an 710072 China Dept. of Mechanical and Industrial Engineering Concordia University Montreal QC H3G 2W1 Canada Diagnosis Flight Control and Simulation Lab. Dept. of Mechanical and Industrial Engineering Concordia University Montreal QC H3G 2W1 Canada Mechanical and Industrial Engineering Department Concordia University Montreal QC H3G 2W1 Canada

ISBN: (纸本)9781424451418

Information synchronization is the key technology of multi-UAV in formation flight. Based on the linear update law, this paper develops a general analytical solution of synchronization for a ring communication topological structure. Considering the fact that GPS is vulnerable to fail in some circumstances which may lead to that the localization of the UAV cannot continue, we propose a localization method by other members' measurements in the UAV team. First, we assume that these UAVs construct a ring communication topological structure and all the units in the network can respectively obtain the position information of the UAV by measuring the relative range and the azimuth from the UAV. Next, the information is synchronized in the ring communication network and it converges to a same value. Finally, the data is communicated to the UAV whose GPS receiver works improperly so that the UAV is capable of continuing the navigation task. Simulation results in Matlab/Simulink show the effectiveness of the proposed approach. © 2010 IEEE.

关键词： Unmanned aerial vehicles (UAV)

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Constrained Holistic Cornering control

Constrained Holistic Cornering Control

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American control Conference

作者： Dhanaraja Kasinathan Amir Khajepour Shih-Ken Chen Bakhtiar Litkouhi Mechanical and Mechatronics Engineering University of Waterloo Waterloo ON N2L3G1 Canada Electrical and Control Systems Research Lab General Motors LLC Warren MI 48090 USA

ISBN: (纸本)9781479932757

The objective of the Holistic Corner control (HCC) is to keep the vehicle on a target path by minimizing the error between the actual and target center of gravity (CG) forces and moment. A real time optimization procedure has been proposed in order to calculate the necessary tire force adjustments to minimize the error and to give the driver a normal driving feel even though the road conditions differ from what is perceived. In this paper, we extend the HCC methodology by adding constraints to the optimization problem. Some important applications are (1) differential braking on all wheels (AWD), applicable to both electrically driven wheels or conventional cars;and (2) hybrid torque vectoring on front wheels (FWD) and differential braking on the rear wheels. Performance of the constrained HCC is compared against the HCC optimization using both simulation and experimental results.

关键词： Wheels Vehicles Torque Tires Optimization Force Vectors

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High-Precision Heading control of an Autonomous Sailboat: A Robust Nonlinear Approach

High-Precision Heading Control of an Autonomous Sailboat: A ...

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OCEANS

作者： Sean Smith Emmanuel Witrant Ya-Jun Pan GIPSA-lab Université Grenoble Alpes - CNRS Grenoble France Department of Mechanical Engineering Dalhousie University Halifax NS Canada Department of Mechanical Engineering Advanced Control and Mechatronics Laboratory Dalhousie University Halifax NS Canada

ISBN: (数字)9798331540081

ISBN: (纸本)9798331540098

This article investigates high-precision robust heading control for an autonomous sailboat. First, the mathematical model of an autonomous sailboat is highlighted and discussed, with a particular focus on the heading dynamics that must be robustly controlled under real-world conditions. Typical control difficulties such as system disturbances, modeling uncertainty, control actuation saturation, and measurement noise are considered and addressed with reference to the controller and system modeling. We propose a control method that ensures robust heading control of an autonomous sailboat in the presence of these challenges. A reference simulator in Matlab/Simulink is used as a simulation testbed to demonstrate the benefits of state-of-the-art robust control developments. A multiphase simulation is conducted to compare the advantages and disadvantages of model-based robust control with linear techniques such as proportional-integral-derivative (PID) control.

关键词： Robust control Uncertainty Sensitivity PI control Noise Sea measurements Systems modeling Mathematical models PD control Testing

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A Novel Cutting Method for Face-Hobbed Spiral Bevel Gears Based on Tool Path Modification

A Novel Cutting Method for Face-Hobbed Spiral Bevel Gears Ba...

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2021 International Conference on Advanced Technologies and Applications of Modern Industry, ATAMI 2021

作者： Li, Lingzhi Guo, Wenchao Yang, Huawei Mao, Shimin State Key Lab. of Comprehensive Technology on Automobile Vibration and Noise and Safety Control No.1 Xinhongqi Street Changchun130013 China School of Mechanical Engineering Xi'An Jiaotong University Xianning West Road 28 Xi'an710049 China

A novel tooth surface design method of face-hobbed spiral bevel gears is proposed, which utilizes a solid cutter without axis tilting through tool path control combining with optimized cutter blade profile to control tooth contact patterns and realize tooth lengthwise chamfering. Firstly, a gear tooth surface generating plan of tool path controlling actively is developed, the mathematical model of the tool path is built, and the equations are given in detail, the determination method of all control parameters is also described. Next, the tooth surface functions of generating gear and machined gear are established based on a mathematic model of the traditional cradle machine tool. Then, the machine setting is also given in concise equations. Finally, the tooth contact analysis is also conducted for a specific gear pair to validate the validity and the reasonability of the new tooth modification method. © Published under licence by IOP Publishing Ltd.

关键词： Machine tools

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Fabrication grammars: bridging design and robotics to control emergent material expressions

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Construction Robotics 2021年第1期5卷 35-48页

作者： Iremnur Tokac Johan Philips Herman Bruyninckx Andrew Vande Moere Design Department of Architecture KU Leuven Leuven Belgium Robotics Automation and Mechatronics Department of Mechanical Engineering KU Leuven Leuven Belgium Flanders Make@KU Leuven Core Lab ROB Heverlee Belgium Control Systems Technology Department of Mechanical Engineering Technical University Eindhoven Eindhoven Netherlands

Designers physically engage with a material to experience how certain characteristics allow the fabrication of unique expressions. In digital fabrication, however, this improvisational negotiation is typically replaced by a virtual simulation that predicts how a material expression can be fabricated, limiting the resulting design language to algorithmic forms. In contrast, we believe that digital fabrication can also produce ‘emergent’ material expressions that are so confounded that they appear slightly differently even when being produced by identical operations. This paper argues that such expressions can be executed by a domain-driven feedback paradigm, which integrates a human-in-the-loop to encode the tacit fabrication knowledge that is generated by reviewing intermediate outcomes. We encode this tacit knowledge by fabrication grammars, rule-based descriptions that causally relate fabrication parameters to qualitative descriptions of material expressions. By documenting a set of Single Point Incremental Forming experiments, this paper demonstrates how emergent material expressions can be controlled by semantically meaningful fabrication grammars, which even can be combined towards purposeful design goals. We believe our findings might allow the digital fabrication of material expressions that appear to have been produced manually or naturally; and support the future sharing of tacit fabrication knowledge.

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A Numerical Modelling for Laser Powder-Bed Fusion of Ti-Alloy with a Hybrid Heat Source: An Investigation on Solidification and Microstructure Formation

SSRN

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SSRN 2022年

作者： Hasanabadi, Mahyar Shahabad, Shahriar Imani Keshavarzkermani, Ali Eybel, Roger Gerlich, Adrian Toyserkani, Ehsan Lab Department of Mechanical and Mechatronics Engineering University of Waterloo WaterlooONN2L 3G1 Canada Lab Department of Mechanical and Mechatronics Engineering University of Waterloo WaterlooONN2L 3G1 Canada Safran Landing Systems 574 Monarch Avenue AjaxONL1S 2G8 Canada Department of Mechanical and Mechatronics Engineering University of Waterloo WaterlooONN2L 3G1 Canada

Among metal Additive Manufacturing (AM) methods, Laser Powder-bed Fusion (LPBF), is a proven fabrication method to produce complex-shaped parts with tailored properties. To achieve the desired properties, proper LPBF modelling facilitates the understanding of the correlation between input process parameters and output microstructure. In this paper, a numerical heat transfer modelling with a novel hybrid volumetric heat source has been proposed to simulate the LPBF of metastable beta titanium alloy (Ti-5553). The developed hybrid model, provides a reliable estimation of temperature distribution and thermal variables (e.g., temperature gradient G and solidification rate R), for any location of the melt pools, during solidification. For the process parameters which provide conduction melting mode, the simulated results agree well with experimentally measured melt pool dimensions where the verified model can also predict grain morphology, grain growth direction, and dendrite size. An in-depth analysis of predicted G/R values at the solidification front reveals that the center of the melt pool has a higher preference for equiaxed grain structure formation, while columnar grains are always dominant at melt pool boundaries. In addition, the scanning speed parameter was found to have a stronger influence on thermal conditions compared to laser power. © 2022, The Authors. All rights reserved.

关键词： Titanium alloys

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The Impact of Robots’ Facial Emotional Expressions on Light Physical Exercises

arXiv

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arXiv 2023年

作者： Abdulazeem, Nourhan Hu, Yue Active & Interactive Robotics Lab Department of Mechanical and Mechatronics Engineering University of Waterloo WaterlooONN2L3G1 Canada

To address the global challenge of population aging, our goal is to enhance successful aging through the introduction of robots capable of assisting in daily physical activities and promoting light exercises, which would enhance the cognitive and physical well-being of older adults. Previous studies have shown that facial expressions can increase engagement when interacting with robots. This study aims to investigate how older adults perceive and interact with a robot capable of displaying facial emotions while performing a physical exercise task together. We employed a collaborative robotic arm with a flat panel screen to encourage physical exercise across three different facial emotion conditions. We ran the experiment with older adults aged between 66 and 88. Our findings suggest that individuals perceive robots exhibiting facial expressions as less competent than those without such expressions. Additionally, the presence of facial expressions does not appear to significantly impact participants’ levels of engagement, unlike other state-of-the-art studies. This observation is likely linked to our study’s emphasis on collaborative physical human-robot interaction (pHRI) applications, as opposed to socially oriented pHRI applications. Additionally, we foresee a requirement for more suitable non-verbal social behavior to effectively enhance participants’ engagement levels. Copyright © 2023, The Authors. All rights reserved.

关键词： Robotic arms

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Time-varying port-representation of dissipative structures with gauge transformations 9

Time-varying port-representation of dissipative structures w...

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2007 9th European control Conference, ECC 2007

作者： Nishida, Gou Yamakita, Masaki Luo, Zhi-Wei Institute of Physical and Chemical Research Bio-Mimetic Control Research Center Environment Adaptive Robotic Systems Lab. 2271-130 Anagahora Nagoya AichiN463-0003 Japan Department of Mechanical and Control Engineering Tokyo Institute of Technology 2-12-1 Oookayama Meguro-ku152-8552 Japan Department of Computer and Systems Engineering Kobe University 1-1 Rokkodai Nada-ku Hyogo657-8501 Japan

ISBN: (纸本)9783952417386

A distributed-port-Hamiltonian system is a generalized model for passivity-based controls. The system representation has been extended to an infinite-dimensional conservative system derived from variational calculus, which is called a field-port-Lagrangian system. A lot of practical systems for control engineering include dissipative elements;however such a non-conservative structure usually cannot be defined by a variational problem. This paper shows that a system with the dissipative structure can be defined as a time-varying fieldport-Lagrangian system by a gauge transformation. First, we show that the gauge transformation generates a time-dependent Lagrangian density functional that introduces the time-varying port-representation. Next, we present that a class of dissipative systems can be identified with a conservative system possessing an internal irreversible energy flow. Finally, we illustrate an equation of elastic films with viscosity damping with the time-varying port-representation. © 2007 EUCA.

关键词： Variational techniques

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