Real time implementation of socially acceptable collision avoidance of a low speed autonomous shuttle using the elastic band method

Mechatronics ◽  
2018 ◽  
Vol 50 ◽  
pp. 341-355 ◽  
Author(s):  
Haoan Wang ◽  
Antonio Tota ◽  
Bilin Aksun-Guvenc ◽  
Levent Guvenc
Keyword(s):  
Real Time ◽  
Collision Avoidance ◽  
Elastic Band ◽  
Low Speed ◽  
Band Method

MPC Based Automated Steering of a Low Speed Shuttle for Socially Acceptable Accident Avoidance

2016 ◽  
Author(s):  
Haoan Wang ◽  
Yue Cao ◽  
Bilin Aksun Güvenç ◽  
Levent Güvenç
Keyword(s):  
Collision Avoidance ◽  
Free Path ◽  
Path Following ◽  
Front Wheel ◽  
State University ◽  
Steering Control ◽  
Elastic Band ◽  
Road Users ◽  
Band Method ◽  
The Ohio State University

This paper presents a socially acceptable collision avoidance system for an automated vehicle based on the elastic band method. Both stationary and moving Vulnerable Road Users (VRUs: pedestrians or bicyclists) are considered in the proposed system. A collision free path is first determined and then Model Predictive Control (MPC) based vehicle front wheel steering is applied to track this collision free path. For the purposes of benchmarking and comparison, the results of a conventional PID steering controller are also presented. The designed system is tested with simulations on a path chosen from the west campus of the Ohio State University, whose waypoints are extracted automatically from OpenStreetMap (OSM). Simulation results show that the MPC based steering control system successfully achieves the required collision avoidance and path following and has comparable or better performance when compared with the conventional PID solution.

scholarly journals Ab Initio Investigation of Helium Mobility in La2Zr2O7 Pyrochlore

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 667
Author(s):  
Yanxia Lu ◽  
Qing Peng ◽  
Chenguang Liu
Keyword(s):  
Nuclear Waste ◽  
Density Functional ◽  
Minimum Energy ◽  
Elastic Band ◽  
Waste Forms ◽  
Band Method ◽  
And Migration ◽  
High Level ◽  
Migration Pathways ◽  
Nuclear Waste Forms

The α-decay of incorporated actinides continuously produces helium, resulting in helium accumulation and causing security concerns for nuclear waste forms. The helium mobility is a key issue affecting the accumulation and kinetics of helium. The energy barriers and migration pathways of helium in a potential high-level nuclear waste forms, La2Zr2O7 pyrochlore, have been investigated in this work using the climbing image nudged elastic band method with density functional theory. The minimum energy pathway for helium to migrate in La2Zr2O7 is identified as via La–La interstitial sites with a barrier of 0.46 eV. This work may offer a theoretical foundation for further prospective studies of nuclear waste forms.

Longitudinal and lateral collision avoidance control strategy for intelligent vehicles

2021 ◽  
pp. 095440702110240
Author(s):  
Ziyu Zhang ◽  
Chunyan Wang ◽  
Wanzhong Zhao ◽  
Jian Feng
Keyword(s):  
Real Time ◽  
Collision Avoidance ◽  
Decentralized Control ◽  
Control Strategy ◽  
Centralized Control ◽  
Lateral Control ◽  
Time Performance ◽  
Collision Avoidance Control ◽  
Avoidance Control ◽  
Control Accuracy

In order to solve the problems of longitudinal and lateral control coupling, low accuracy and poor real-time of existing control strategy in the process of active collision avoidance, a longitudinal and lateral collision avoidance control strategy of intelligent vehicle based on model predictive control is proposed in this paper. Firstly, the vehicle nonlinear coupling dynamics model is established. Secondly, considering the accuracy and real-time requirements of intelligent vehicle motion control in pedestrian crossing scene, and combining the advantages of centralized control and decentralized control, an integrated unidirectional decoupling compensation motion control strategy is proposed. The proposed strategy uses two pairs of unidirectional decoupling compensation controllers to realize the mutual integration and decoupling in both longitudinal and lateral directions. Compared with centralized control, it simplifies the design of controller, retains the advantages of centralized control, and improves the real-time performance of control. Compared with the decentralized control, it considers the influence of longitudinal and lateral control, retains the advantages of decentralized control, and improves the control accuracy. Finally, the proposed control strategy is simulated and analyzed in six working conditions, and compared with the existing control strategy. The results show that the proposed control strategy is obviously better than the existing control strategy in terms of control accuracy and real-time performance, and can effectively improve vehicle safety and stability.

scholarly journals COLREG-Compliant Optimal Path Planning for Real-Time Guidance and Control of Autonomous Ships

2021 ◽  
Vol 9 (4) ◽  
pp. 405
Author(s):  
Raphael Zaccone
Keyword(s):  
Path Planning ◽  
Real Time ◽  
Collision Avoidance ◽  
Autonomous Navigation ◽  
Optimal Path ◽  
Open Water ◽  
Optimal Path Planning ◽  
Guidance And Control ◽  
Real Time Applications ◽  
And Control

While collisions and groundings still represent the most important source of accidents involving ships, autonomous vessels are a central topic in current research. When dealing with autonomous ships, collision avoidance and compliance with COLREG regulations are major vital points. However, most state-of-the-art literature focuses on offline path optimisation while neglecting many crucial aspects of dealing with real-time applications on vessels. In the framework of the proposed motion-planning, navigation and control architecture, this paper mainly focused on optimal path planning for marine vessels in the perspective of real-time applications. An RRT*-based optimal path-planning algorithm was proposed, and collision avoidance, compliance with COLREG regulations, path feasibility and optimality were discussed in detail. The proposed approach was then implemented and integrated with a guidance and control system. Tests on a high-fidelity simulation platform were carried out to assess the potential benefits brought to autonomous navigation. The tests featured real-time simulation, restricted and open-water navigation and dynamic scenarios with both moving and fixed obstacles.

scholarly journals A Probabilistic Model for Real-Time Semantic Prediction of Human Motion Intentions from RGBD-Data

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4141
Author(s):  
Wouter Houtman ◽  
Gosse Bijlenga ◽  
Elena Torta ◽  
René van de Molengraft
Keyword(s):  
Real Time ◽  
Collision Avoidance ◽  
Probabilistic Model ◽  
Real Life ◽  
Human Motion ◽  
Model Based ◽  
Multiple Hypotheses ◽  
Navigation Algorithms ◽  
The Right ◽  
Motion Behavior

For robots to execute their navigation tasks both fast and safely in the presence of humans, it is necessary to make predictions about the route those humans intend to follow. Within this work, a model-based method is proposed that relates human motion behavior perceived from RGBD input to the constraints imposed by the environment by considering typical human routing alternatives. Multiple hypotheses about routing options of a human towards local semantic goal locations are created and validated, including explicit collision avoidance routes. It is demonstrated, with real-time, real-life experiments, that a coarse discretization based on the semantics of the environment suffices to make a proper distinction between a person going, for example, to the left or the right on an intersection. As such, a scalable and explainable solution is presented, which is suitable for incorporation within navigation algorithms.

Nudged Elastic Band Method for Molecular Reactions Using Energy-Weighted Springs Combined with Eigenvector Following

2021 ◽  
Author(s):  
Vilhjálmur Ásgeirsson ◽  
Benedikt Orri Birgisson ◽  
Ragnar Bjornsson ◽  
Ute Becker ◽  
Frank Neese ◽  
...  
Keyword(s):  
Elastic Band ◽  
Band Method ◽  
Molecular Reactions

scholarly journals CH4 dissociation on the Pd/Cu(111) surface alloy: A DFT study

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 790-798
Author(s):  
Aykan Akça
Keyword(s):  
Catalytic Activity ◽  
Adsorption Energy ◽  
Lower Cost ◽  
Relative Energy ◽  
Catalyst Design ◽  
Elastic Band ◽  
Efficient Catalyst ◽  
Energy Diagram ◽  
Band Method ◽  
Pure Cu

AbstractThe periodic four-layered model of the pure Cu(111) surface has been considered, and the effect of doping with palladium on CH4 dissociation has been investigated. The most stable adsorption geometries of CHx species (x = 1–4) and H atom on the PdCu(111) and pure Cu(111) surfaces have been obtained. Their computed adsorption energy results on the pure Cu(111) surface have been compared with the previously reported studies. Then, transition state geometries of CH4 dehydrogenation steps on both surfaces were calculated by the climbing image nudged elastic band method. Finally, the relative energy diagram for CH4 complete dehydrogenation has been represented. The results show that the PdCu(111) surface is more favorable than the Cu(111) surface in terms of the activation energies. The addition of Pd atoms to the Cu(111) surface significantly improves the catalytic activity. This knowledge can enable an efficient catalyst design at a lower cost using different strategies.

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