scholarly journals A Lightweight Localization Strategy for LiDAR-Guided Autonomous Robots with Artificial Landmarks

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4479
Author(s):  
Sen Wang ◽  
Xiaohe Chen ◽  
Guanyu Ding ◽  
Yongyao Li ◽  
Wenchang Xu ◽  
...  
Keyword(s):  
Optimization Algorithm ◽  
Motion Compensation ◽  
High Speed ◽  
Feature Matching ◽  
Autonomous Robots ◽  
Lidar Data ◽  
Promising Alternative ◽  
Sharp Turn ◽  
Matching Mechanism ◽  
Matching Score

This paper proposes and implements a lightweight, “real-time” localization system (SORLA) with artificial landmarks (reflectors), which only uses LiDAR data for the laser odometer compensation in the case of high-speed or sharp-turning. Theoretically, due to the feature-matching mechanism of the LiDAR, locations of multiple reflectors and the reflector layout are not limited by geometrical relation. A series of algorithms is implemented to find and track the features of the environment, such as the reflector localization method, the motion compensation technique, and the reflector matching optimization algorithm. The reflector extraction algorithm is used to identify the reflector candidates and estimates the precise center locations of the reflectors from 2D LiDAR data. The motion compensation algorithm predicts the potential velocity, location, and angle of the robot without odometer errors. Finally, the matching optimization algorithm searches the reflector combinations for the best matching score, which ensures that the correct reflector combination could be found during the high-speed movement and fast turning. All those mechanisms guarantee the algorithm’s precision and robustness in the high speed and noisy background. Our experimental results show that the SORLA algorithm has an average localization error of 6.45 mm at a speed of 0.4 m/s, and 9.87 mm at 4.2 m/s, and still works well with the angular velocity of 1.4 rad/s at a sharp turn. The recovery mechanism in the algorithm could handle the failure cases of reflector occlusion, and the long-term stability test of 72 h firmly proves the algorithm’s robustness. This work shows that the strategy used in the SORLA algorithm is feasible for industry-level navigation with high precision and a promising alternative solution for SLAM.

scholarly journals High-Speed Railway EMUs’ Circulation Plan Optimization: A Two-Stage Optimization Algorithm Based on Column Generation

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 15611-15631
Author(s):  
Wen-Jun Li ◽  
Yu-Ting Wang ◽  
Lei Nie ◽  
Yinghui Wu ◽  
Liu Peng
Keyword(s):  
Column Generation ◽  
Optimization Algorithm ◽  
High Speed ◽  
Two Stage ◽  
High Speed Railway ◽  
Plan Optimization

scholarly journals Experimental and numerical analysis of incremental magnetic pulse welding of dissimilar sheet metals

2019 ◽  
Vol 6 ◽  
pp. 7
Author(s):  
Verena Psyk ◽  
Maik Linnemann ◽  
Christian Scheffler
Keyword(s):  
High Speed ◽  
Welding Process ◽  
Deep Understanding ◽  
Magnetic Pulse ◽  
Pulsed Magnetic Fields ◽  
Promising Alternative ◽  
Magnetic Pulse Welding ◽  
Pulse Welding ◽  
The Individual ◽  
Weld Seams

Magnetic pulse welding is a solid-state welding process using pulsed magnetic fields resulting from a sudden discharge of a capacitor battery through a tool coil in order to cause a high-speed collision of two metallic components, thus producing an impact-welded joint. The joint is formed at room temperature. Consequently, temperature-induced problems are avoided and this technology enables the use of material combinations, which are usually considered to be non-weldable. The extension of the typically linear weld seam can reach several hundred millimetres in length, but only a few millimetres in width. Incremental or sequential magnetic pulse welding is a promising alternative to obtain larger connected areas. Here, the inductor is moved relative to the joining partners after the weld sequence and then another welding process is initiated. Thus, the welded area is extended by arranging multiple adjacent weld seams. This article demonstrates the feasibility of incremental magnetic pulse welding. Furthermore, the influence of important process parameters on the component quality is investigated and evaluated. The suitability of different mechanical testing methods for determining the strength of the individual weld seams is discussed. The results of numerical simulation are consulted in order to obtain deep understanding of the observed effects.

Special Issue on New Challenges in Robotics Technology

2017 ◽  
Vol 11 (3) ◽  
pp. 343-343
Author(s):  
Terenziano Raparelli ◽  
◽  
Pierluigi Beomonte Zobel
Keyword(s):  
High Speed ◽  
Autonomous Robots ◽  
Control Strategies ◽  
Industrial Applications ◽  
Assistive Devices ◽  
Service Robots ◽  
Practical Case ◽  
Special Issue ◽  
New Challenges ◽  
Robotic Devices

Robotics has reached a top technological level in recent years, a level at which it can be successfully used not only in structured spaces (for less complex applications) but also increasingly in unstructured spaces. Robotics technology is now used effectively in hospitals for rehabilitation and assistive devices, in the home for domestic applications, in the space for autonomous robots and automated vehicles, in amusement parks for entertainment attractions, and on the ground for military applications. In industrial applications, robotics has enlarged its scope with high-speed robots, cooperative robots, and smart robotic devices for production set-ups. These new applications have created new challenges in robotics. New materials have been developed to make frames lighter and smarter, new actuators and sensors have been made in compliance with specific applications and for more advanced performance, new flexible gripper devices have been produced with superior control systems, and new interfaces have been developed that are integrated with the devices and easier to use. This special issue features 18 research articles related to the latest research results and practical case studies in robotics technology. Subjects include robots for rehabilitation, robots as assistive devices, robots for agriculture, robots for exploration, robots for automation and industrial applications, service robots, new actuators, new sensors, new gripping devices, new control strategies, and robotic systems. We deeply appreciate the careful efforts of all the authors and thank the reviewers for their incisive efforts. Without these contributions, this special issue could not have been printed. We hope that this special issue will trigger further research on robotics technology. Finally a special memory of Cesare Rossi, one of the authors, that died suddenly after the preparation of the manuscript.

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