An Advanced Anti-Slip Control Algorithm for Locomotives Under Complex Friction Conditions

2021 ◽  
Author(s):  
Yunfan Yang ◽  
Liang Ling ◽  
Tao Zhang ◽  
Kaiyun Wang ◽  
Wanming Zhai
Keyword(s):  
High Power ◽  
Control Algorithm ◽  
Three Dimensional ◽  
Time Estimation ◽  
Threshold Values ◽  
Dynamic Interactions ◽  
Slip Control ◽  
Heavy Haul Train ◽  
Control Threshold ◽  
Heavy Haul

Abstract The locomotive wheelsets configured with high-power AC traction motors are very prone to slip under poor friction conditions, which usually impair traction/braking efficiency. To avoid the adverse consequence caused by the conspicuous slipping behaviors of wheels, the anti-slip control modules are consequently equipped on high-power locomotives. This paper presents an advanced anti-slip control algorithm for heavy-haul locomotives travelling with complex wheel/rail friction conditions. The proposed anti-slip control model is implemented in a three-dimensional (3D) heavy-haul train-track coupled dynamics model, in which the real-time estimation of wheel/rail adhesion conditions and relevant optimization adjustment of control threshold values are considered. The wheel/rail dynamic interactions of the heavy-haul locomotive under traction/braking conditions and multifarious friction conditions are investigated. The control effects of the anti-slip controllers with changeable and constant threshold values are compared. It is shown that the traction/braking loads and friction conditions have a significant effect on wheel/rail interactions. The optimal traction/braking efficiency can be realized by adopting the anti-slip controller with alterable threshold values.

scholarly journals A Three-Phase Fundamental Diagram from Three-Dimensional Traffic Data

Axioms ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 17
Author(s):  
Maria Laura Delle Delle Monache ◽  
Karen Chi ◽  
Yong Chen ◽  
Paola Goatin ◽  
Ke Han ◽  
...  
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Time Estimation ◽  
Travel Time Estimation ◽  
Traffic Data ◽  
Fundamental Diagram ◽  
Model Based Clustering ◽  
Three Phase ◽  
Characterization Of Solutions ◽  
Two Phases

This paper uses empirical traffic data collected from three locations in Europe and the US to reveal a three-phase fundamental diagram with two phases located in the uncongested regime. Model-based clustering, hypothesis testing and regression analyses are applied to the speed–flow–occupancy relationship represented in the three-dimensional space to rigorously validate the three phases and identify their gaps. The finding is consistent across the aforementioned different geographical locations. Accordingly, we propose a three-phase macroscopic traffic flow model and a characterization of solutions to the Riemann problems. This work identifies critical structures in the fundamental diagram that are typically ignored in first- and higher-order models and could significantly impact travel time estimation on highways.

A three-dimensional porous LiFePO4 cathode material modified with a nitrogen-doped graphene aerogel for high-power lithium ion batteries

2015 ◽  
Vol 8 (3) ◽  
pp. 869-875 ◽  
Author(s):  
Bo Wang ◽  
Wael Al Abdulla ◽  
Dianlong Wang ◽  
X. S. Zhao
Keyword(s):  
Lithium Ion Batteries ◽  
High Power ◽  
Diffusion Length ◽  
Three Dimensional ◽  
Lithium Ion ◽  
Graphene Aerogel ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene ◽  
Lifepo4 Cathode

LFP@N-GA with (010) facet oriented LFP NPs embedded in N-GA provides both rapid Li+ and electron pathways in the electrode as well as short Li+ diffusion length in LFP crystals.

Finite Element Simulation of a Strong-Post W-Beam Guardrail System

SIMULATION ◽  
2002 ◽  
Vol 78 (10) ◽  
pp. 587-599 ◽  
Author(s):  
Ali O. Atahan
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Full Scale ◽  
Nonlinear Finite Element ◽  
Crash Test ◽  
Original Design ◽  
Dynamic Interactions ◽  
Crash Testing ◽  
Element Simulation ◽  
Test Requirements

Computer simulation of vehicle collisions has improved significantly over the past decade. With advances in computer technology, nonlinear finite element codes, and material models, full-scale simulation of such complex dynamic interactions is becoming ever more possible. In this study, an explicit three-dimensional nonlinear finite element code, LS-DYNA, is used to demonstrate the capabilities of computer simulations to supplement full-scale crash testing. After a failed crash test on a strong-post guardrail system, LS-DYNA is used to simulate the system, determine the potential problems with the design, and develop an improved system that has the potential to satisfy current crash test requirements. After accurately simulating the response behavior of the full-scale crash test, a second simulation study is performed on the system with improved details. Simulation results indicate that the system performs much better compared to the original design.

scholarly journals An anthropomorphic soft skeleton hand exploiting conditional models for piano playing

2018 ◽  
Vol 3 (25) ◽  
pp. eaau3098 ◽  
Author(s):  
J. A. E. Hughes ◽  
P. Maiolino ◽  
F. Iida
Keyword(s):  
Three Dimensional ◽  
Piano Music ◽  
Robotic Manipulators ◽  
Mechanical Stiffness ◽  
Dynamic Interactions ◽  
Conditional Model ◽  
Three Dimensional Printing ◽  
Behavioral Diversity ◽  
Research Challenge ◽  
Dimensional Printing

The development of robotic manipulators and hands that show dexterity, adaptability, and subtle behavior comparable to human hands is an unsolved research challenge. In this article, we considered the passive dynamics of mechanically complex systems, such as a skeleton hand, as an approach to improving adaptability, dexterity, and richness of behavioral diversity of such robotic manipulators. With the use of state-of-the-art multimaterial three-dimensional printing technologies, it is possible to design and construct complex passive structures, namely, a complex anthropomorphic skeleton hand that shows anisotropic mechanical stiffness. We introduce a concept, termed the “conditional model,” that exploits the anisotropic stiffness of complex soft-rigid hybrid systems. In this approach, the physical configuration, environment conditions, and conditional actuation (applied actuation) resulted in an observable conditional model, allowing joint actuation through passivity-based dynamic interactions. The conditional model approach allowed the physical configuration and actuation to be altered, enabling a single skeleton hand to perform three different phrases of piano music with varying styles and forms and facilitating improved dynamic behaviors and interactions with the piano over those achievable with a rigid end effector.

scholarly journals Three-dimensional stable lithium metal anode with nanoscale lithium islands embedded in ionically conductive solid matrix

2017 ◽  
Vol 114 (18) ◽  
pp. 4613-4618 ◽  
Author(s):  
Dingchang Lin ◽  
Jie Zhao ◽  
Jie Sun ◽  
Hongbin Yao ◽  
Yayuan Liu ◽  
...  
Keyword(s):  
High Power ◽  
Power Output ◽  
Three Dimensional ◽  
Rechargeable Batteries ◽  
Solid Matrix ◽  
Side Reactions ◽  
Surface Protection ◽  
Metal Anode ◽  
Practical Applications ◽  
Significant Step

Rechargeable batteries based on lithium (Li) metal chemistry are attractive for next-generation electrochemical energy storage. Nevertheless, excessive dendrite growth, infinite relative dimension change, severe side reactions, and limited power output severely impede their practical applications. Although exciting progress has been made to solve parts of the above issues, a versatile solution is still absent. Here, a Li-ion conductive framework was developed as a stable “host” and efficient surface protection to address the multifaceted problems, which is a significant step forward compared with previous host concepts. This was fulfilled by reacting overstoichiometry of Li with SiO. The as-formed LixSi–Li2O matrix would not only enable constant electrode-level volume, but also protect the embedded Li from direct exposure to electrolyte. Because uniform Li nucleation and deposition can be fulfilled owing to the high-density active Li domains, the as-obtained nanocomposite electrode exhibits low polarization, stable cycling, and high-power output (up to 10 mA/cm2) even in carbonate electrolytes. The Li–S prototype cells further exhibited highly improved capacity retention under high-power operation (∼600 mAh/g at 6.69 mA/cm2). The all-around improvement on electrochemical performance sheds light on the effectiveness of the design principle for developing safe and stable Li metal anodes.

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