Searched for: author%3A%22Li%2C+S.%22
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Zhang, P. (author), Li, S. (author), Li, Z. (author)
Short pitch corrugation is a quasi-periodic rail defect that induces a high level of noise and accelerates track degradation. This paper proposes a methodology to mitigate short pitch corrugation by rail constraint design, including four steps. In Step 1, corrugation is numerically reproduced by employing a three-dimensional (3D) finite...
journal article 2023
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Li, S. (author), Naeimi, M. (author), He, C. (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)
The mechanism of rail short pitch corrugation has remained elusive in the past. The damage mechanisms of the corrugation are reported to be differential wear or plastic deformation. The former has been extensively studied, while the plastic deformation, especially under multiple wheel passages has been seldom studied. To uncover the facts...
journal article 2023
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Li, S. (author)
In response to the pressing demand for elderly care, care robots, the robots used by care receivers and/or caregivers for care purposes in various settings, such as hospitals, nursing homes, and personal residences were introduced and have been gaining traction as a technological solution to improve care quality and to enhance the value of...
doctoral thesis 2022
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Li, S. (author)
Short pitch corrugation is a (quasi-) sinusoidal rail vertical defect on rail surface, and it was first found more than one century ago. The wavelength of short pitch corrugation is 20-80 mm, and its amplitude can be up to 100 µm. It mainly develops on straight tracks or at gentle curves with comparatively light axle loads. Due to short pitch...
doctoral thesis 2022
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Li, S. (author), de Wagter, C. (author), de Croon, G.C.H.E. (author)
Wireless ranging measurements have been proposed for enabling multiple Micro Air Vehicles (MAVs) to localize with respect to each other. However, the high-dimensional relative states are weakly observable due to the scalar distance measurement. Hence, the MAVs have degraded relative localization and control performance under unobservable...
journal article 2022
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Li, S. (author), de Wagter, C. (author), de Croon, G.C.H.E. (author)
Relative localization is an important ability for multiple robots to perform cooperative tasks in GPS-denied environments. This paper presents a novel autonomous positioning framework for monocular relative localization of multiple tiny flying robots. This approach does not require any groundtruth data from external systems or manual labeling....
conference paper 2022
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Wang, L. (author), Li, S. (author), Wang, Ping (author), Chen, Rong (author), Li, Z. (author)
The continuous homogeneous rail constraint of embedded rail system (ERS) is realized by the encapsulation of rails with the elastic poured compound (EPC) which is a composite material. Previous treatment of EPC as linear elastic material was insufficient in the failure analysis of ERS. In this work, a hyperelastic model is developed to...
journal article 2022
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Li, Z. (author), Li, S. (author), Zhang, P. (author), Nunez, Alfredo (author), Dollevoet, R.P.B.J. (author)
This paper proposes a new hypothesis for the formation process of short pitch rail corrugation. An FE wheel-track dynamic model is utilized to verify the hypothesis by reproducing corrugation initiation and consistent growth. It is found longitudinal compression modes are responsible for corrugation initiation with necessary initial...
journal article 2022
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Pfeiffer, S.U. (author), Munaro, Veronica (author), Li, S. (author), Rizzo, Alessandro (author), de Croon, G.C.H.E. (author)
Relative localization is a key capability for autonomous robot swarms, and it is a substantial challenge, especially for small flying robots, as they are extremely restricted in terms of sensors and processing while other robots may be located anywhere around them in three-dimensional space. In this article, we generalize wireless ranging...
journal article 2022
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He, C. (author), Yang, Z. (author), Zhang, P. (author), Li, S. (author), Naeimi, M. (author), Li, Z. (author)
Polygonal wear is a common type of damage on the railway wheel tread, which could induce wheel-rail impacts and further components failure. This study presents a finite element (FE) thermomechanical model to investigate the causes of wheel polygonal wear. The FE model is able to cope with three possible causes of polygonal wear: thermal...
conference paper 2022
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Li, S. (author)
In the last decade, the research field of aerial swarms has grown at a rapid pace. These multi-robot systems possess desirable abilities including mobility in 3D spaces, efficient task execution in parallel, and redundant characteristics for fault tolerance. Many applications with multiple flying robots have already been demonstrated, such as...
doctoral thesis 2021
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Wu, Changsheng (author), Rwei, A.Y. (author), Lee, Jong Yoon (author), Ouyang, Wei (author), Jacobson, Lauren (author), Shen, Haixu (author), Luan, Haiwen (author), Xu, Yameng (author), Li, S. (author)
Background Current near-infrared spectroscopy (NIRS)-based systems for continuous flap monitoring are highly sensitive for detecting malperfusion. However, the clinical utility and user experience are limited by the wired connection between the sensor and bedside console. This wire leads to instability of the flap-sensor interface and may...
journal article 2021
document
Li, S. (author), de Wagter, C. (author), de Croon, G.C.H.E. (author)
Wireless ranging measurements have been proposed for enabling multiple Micro Air Vehicles (MAVs) to localize with respect to each other. However, the high-dimensional relative states are weakly observable due to the scalar distance measurement. Hence, the MAVs have degraded relative localization and control performance under unobservable...
conference paper 2021
document
Liang, Hongqin (author), Li, Wei (author), Zhou, Zhijun (author), Wen, Zefeng (author), Li, S. (author), An, Dong (author)
Based on the measured spectra of rail roughness and track structures longitudinal roughness, the rail grinding limit is studied with the help of an established coupled dynamic metro vehicle–track model and a rolling contact fatigue model. The results indicate that metro rail grinding control should be regulated according to corrugation...
journal article 2021
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Zhang, P. (author), Li, S. (author), Nunez, Alfredo (author), Li, Z. (author)
This paper investigates three-dimensional (3D) rail vibrations under fastening constraint up to 5000 Hz and provides insights into rail vibration control by fastening parameters. A methodology is proposed, including experimental investigation and numerical simulations of rail vibrations. Three steps are considered: 1) experimental investigation...
journal article 2021
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Zhang, P. (author), Li, S. (author), Nunez, Alfredo (author), Li, Z. (author)
In this paper, we present a solution method based on finite element (FE) modeling to predict multimodal dispersive waves in a free rail. As well as the modal behaviors and wavenumber-frequency dispersion relations, the phase and group velocities of six types of propagative waves are also derived and discussed in detail in the frequency range...
journal article 2021
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Li, S. (author)
Drones, especially quadrotors, have shown their great value for applications like aerial photography, object delivery and warehouse inspection. At the same time, with the de- velopment of Artificial Intelligence (AI), computers can replace humans and even per- form better than humans in some areas where it was impossible before like the AI pro-...
doctoral thesis 2020
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Li, S. (author), van der Horst, E. (author), Duernay, Philipp (author), de Wagter, C. (author), de Croon, G.C.H.E. (author)
Drone racing is becoming a popular e-sport all over the world, and beating the best human drone race pilots has quickly become a new major challenge for artificial intelligence and robotics. In this paper, we propose a novel sensor fusion method called visual model-predictive localization (VML). Within a small time window, VML approximates...
journal article 2020
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Wang, L. (author), Wang, Ping (author), Chen, Rong (author), Li, S. (author), Li, Z. (author)
Embedded rail system (ERS) is a new type of track structure with many advantages due to its continuous rail support. The rapid development of urban rail transit all over the world renders its application prospect broad. However, the cracks and debonds in ERS present a threat to the traffic safety and a possibility for high maintenance costs....
journal article 2020
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Li, S. (author), de Wagter, C. (author), de Croon, G.C.H.E. (author)
Autonomous robots heavily rely on well-tuned state estimation filters for successful control. This letter presents a novel automatic tuning strategy for learning filter parameters by minimizing the innovation, i.e., the discrepancy between expected and received signals from all sensors. The optimization process only requires the inputs and...
journal article 2019
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