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A Conflict-Reducing Path Planning Algorithm in Automated Warehouses

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A Conflict-Reducing Path Planning Algorithm in Automated War...

IEEE International Conference on Networking, Sensing and control

作者： Ligen Feng Xinyu Chen Tingqi Zhang Weimin Wu State Key Laboratory of Industrial Control Technology Institute of Cyber-Systems and Control Zhejiang University Hangzhou China

ISBN: (纸本)9781665440493

With the development of modern logistics industry, automated warehouses are becoming more and more widely used. An automated guided vehicle (AGV) is often used to carry goods in warehouse. Under specific limitations of the road layout, AGVs are prone to conflict when moving. According to the layout characteristics of automated warehouses, this paper proposes a conflict-reducing path planning algorithm, which is an improvement of A-star algorithm. The conflict cost and turn cost are introduced to the algorithm to reduce the conflict probability and the number of turns of paths. Through simulation comparison, it is verified that the algorithm can reduce the probability of conflicts among AGVs and improve the overall efficiency of multi-AGV systems.

关键词： Industries Costs Remotely guided vehicles Roads Layout Path planning Sensors

A novel hierarchical charging algorithm for the AGV dispatching problem in a multi-robot system

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A novel hierarchical charging algorithm for the AGV dispatch...

IEEE International Conference on Networking, Sensing and control

作者： Haoyi Niu Weimin Wu Tao Zhang State Key Laboratory of Industrial Control Technology Institute of Cyber-Systems and Control Zhejiang University Hangzhou China

ISBN: (纸本)9781665440493

Charging problem for the AGVs (automated guided vehicles) in a multi-robot system based on a real-world intelligent warehouse aims to maximize the transportation efficiency of AGVs considering the charging process. For this purpose, a hierarchical charging algorithm is presented by taking into account both the continuity of transportation and the charging efficiency. A multi-level threshold scheme is designed to reduce the impact of the charging process on AGV scheduling. The numerical experiment results indicate that at the same charging rate, the number of completed tasks by AGVs can be increased from 18 to 28 an hour compared with traditional charging algorithm thus the efficiency can be improved from 34.62% to 51.86% correspondingly, which shows the superior performance of the presented algorithm.

关键词： Remotely guided vehicles Job shop scheduling Service robots Transportation Robot sensing systems Real-time systems Dispatching

Improved radar localization on lidar maps using shared embedding

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arXiv 2021年

作者： Yin, Huan Wang, Yue Xiong, Rong The State Key Laboratory of Industrial Control Technology Institute of Cyber-Systems and Control Zhejiang University Zhejiang China

We present a heterogeneous localization framework for solving radar global localization and pose tracking on pre-built lidar maps. To bridge the gap of sensing modalities, deep neural networks are constructed to create shared embedding space for radar scans and lidar maps. Herein learned feature embeddings are supportive for similarity measurement, thus improving map retrieval and data matching respectively. In RobotCar and MulRan datasets, we demonstrate the effectiveness of the proposed framework with the comparison to Scan Context and RaLL. In addition, the proposed pose tracking pipeline is with less neural networks compared to the original RaLL. Copyright © 2021, The Authors. All rights reserved.

关键词： Optical radar

A Dynamic Joint Real-time Scheduling Strategy of Truck and Yard Crane in Container Terminals

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A Dynamic Joint Real-time Scheduling Strategy of Truck and Y...

IEEE International Conference on Networking, Sensing and control

作者： Xiaojie Jin Xingkai Wang Weimin Wu Zhenrui Rong Quanling Zhang State Key Laboratory of Industrial Control Technology Institute of Cyber-Systems and Control Zhejiang University Hangzhou China

ISBN: (纸本)9781665440493

With the continuous growth of port container throughput, it is difficult to meet the port production demand by simply configuring automation equipments to improve the operation efficiency of machinery. The container truck scheduling and yard crane scheduling are the two important scheduling links in container terminals. At the same time, there is a tight coupling between them. Thus, the joint scheduling of container trucks and yard cranes is necessary to improve the operation efficiency of container terminals. In this paper, the joint real-time scheduling of trucks and yard cranes is mathematically modeled, and is solved by the elite genetic algorithm. Finally, a variety of scheduling strategies are compared to verify the effectiveness of the proposed strategy.

关键词： Cranes Loading Production Containers Dynamic scheduling Throughput Real-time systems

Efficient learning of goal-oriented push-grasping synergy in clutter

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arXiv 2021年

作者： Xu, Kechun Yu, Hongxiang Lai, Qianen Wang, Yue Xiong, Rong State Key Laboratory of Industrial Control Technology Institute of Cyber-Systems and Control Zhejiang University Hangzhou China

—We focus on the task of goal-oriented grasping, in which a robot is supposed to grasp a pre-assigned goal object in clutter and needs some pre-grasp actions such as pushes to enable stable grasps. However, in this task, the robot gets positive rewards from environment only when successfully grasping the goal object. Besides, joint pushing and grasping elongates the action sequence, compounding the problem of reward delay. Thus, sample inefficiency remains a main challenge in this task. In this paper, a goal-conditioned hierarchical reinforcement learning formulation with high sample efficiency is proposed to learn a push-grasping policy for grasping a specific object in clutter. In our work, sample efficiency is improved by two means. First, we use a goal-conditioned mechanism by goal relabeling to enrich the replay buffer. Second, the pushing and grasping policies are respectively regarded as a generator and a discriminator and the pushing policy is trained with supervision of the grasping discriminator, thus densifying pushing rewards. To deal with the problem of distribution mismatch caused by different training settings of two policies, an alternating training stage is added to learn pushing and grasping in turn. A series of experiments carried out in simulation and real world indicate that our method can quickly learn effective pushing and grasping policies and outperforms existing methods in task completion rate and goal grasp success rate by less times of motion. Furthermore, we validate that our system can also adapt to goal-agnostic conditions with better performance. Note that our system can be transferred to the real world without any fine-tuning. Our code is available at https://***/xukechun/Efficient_goaloriented_push-grasping_synergy Copyright © 2021, The Authors. All rights reserved.

关键词： Deep learning

Collaborative recognition of feasible region with aerial and ground robots through DPCN

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arXiv 2021年

作者： Li, Yunshuang Huang, Zheyuan Chen, Zexi Wang, Yue Xiong, Rong The State Key Laboratory of Industrial Control Technology Institute of Cyber-Systems and Control Zhejiang University Zhejiang China

Ground robots always get collision in that only if they get close to the obstacles, can they sense the danger and take actions, which is usually too late to avoid the crash, causing severe damage to the robots. To address this issue, we present a collaborative system with aerial and ground robots to gain precise recognition of feasible region. Taking the aerial robots' advantages of having large scale variance of view points of the same route which the ground robots is on, the collaboration work provides global information of road segmentation for the ground robot, thus enabling it to obtain feasible region and adjust its pose ahead of time. Under normal circumstance, the transformation between these two devices can be obtained by GPS yet with much error, directly causing inferior influence on recognition of feasible region. Thereby, we utilize the state-of-the-art research achievements in matching heterogeneous sensor measurements called deep phase correlation network(DPCN), which has excellent performance on heterogeneous mapping, to refine the transformation. The network is light-weighted and promising for better generalization. We use Aero-Ground dataset which consists of heterogeneous sensor images and aerial road segmentation images. The results show that our collaborative system has great accuracy, speed and stability. Copyright © 2021, The Authors. All rights reserved.

关键词： Image segmentation

A Decision-support Framework for Port Container Stowage Plan

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A Decision-support Framework for Port Container Stowage Plan

IEEE International Conference on Networking, Sensing and control

作者： Shuo Wang Tao Zhang Zichao Xing Weimin Wu State Key Laboratory of Industrial Control Technology Institute of Cyber-Systems and Control Zhejiang University Hangzhou China

ISBN: (纸本)9781665440493

With the development of international trade, container transportation increases rapidly. Loading large quantities of containers requires efficient port operations and an efficient container stowage plan (CSP). A CSP is the placement of containers onto the shipping plan slots, which should decrease loading cost and keep the ship stability. The yard operational efficiency, ship stability, and operational safety are the major factors that should be considered in port loading and unloading. Since, factors are related to others, to generate a CSP is proven to be NP-complete. This paper proposes a decision-support framework for determining a shipment plan, which is to achieve the optimal shipment objects by a planning model. The experimental results show that the proposed framework can improve the operating efficiency of the storage yard while keeping the ship’s stability and reducing the dangerous loading scenes.

关键词： International trade Loading Transportation Containers Stability analysis Sensors Safety

Consistent and Asymptotically Statistically-Efficient Solution to Camera Motion Estimation

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arXiv 2024年

作者： Zeng, Guangyang Zeng, Qingcheng Li, Xinghan Mu, Biqiang Chen, Jiming Shi, Ling Wu, Junfeng The School of Data Science Chinese University of Hong Kong Shenzhen Shenzhen518172 China The College of Control Science and Engineering The State Key Laboratory of Industrial Control Technology Zhejiang University Hangzhou310027 China Key Laboratory of Systems and Control Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing100190 China The Department of Electronic and Computer Engineering Hong Kong University of Science and Technology Hong Kong

Given 2D point correspondences between an image pair, inferring the camera motion is a fundamental issue in the computer vision community. The existing works generally set out from the epipolar constraint and estimate the essential matrix, which is not optimal in the maximum likelihood (ML) sense. In this paper, we dive into the original measurement model with respect to the rotation matrix and normalized translation vector and formulate the ML problem. We then propose a two-step algorithm to solve it: In the first step, we estimate the variance of measurement noises and devise a consistent estimator based on bias elimination;In the second step, we execute a one-step Gauss-Newton iteration on manifold to refine the consistent estimate. We prove that the proposed estimate owns the same asymptotic statistical properties as the ML estimate: The first is consistency, i.e., the estimate converges to the ground truth as the point number increases;The second is asymptotic efficiency, i.e., the mean squared error of the estimate converges to the theoretical lower bound - Cramer-Rao bound. In addition, we show that our algorithm has linear time complexity. These appealing characteristics endow our estimator with a great advantage in the case of dense point correspondences. Experiments on both synthetic data and real images demonstrate that when the point number reaches the order of hundreds, our estimator outperforms the state-of-the-art ones in terms of estimation accuracy and CPU time. Copyright © 2024, The Authors. All rights reserved.

关键词： Maximum likelihood estimation

Fuzzy PID controller Optimized by Improved Gravitational Search Algorithm for Load Frequency control in Multi-area Power System

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IAENG International Journal of Computer Science

IAENG International Journal of Computer Science 2022年第1期49卷 125-139页

作者： Chen, Gonggui Qin, Feng Long, Hongyu Zeng, Xianjun Kang, Peng Zhang, Jinming Professor of Key Laboratory of Industrial Internet of Things and Networked Control Ministry of Education Chongqing University of Posts and Telecommunications Chongqing400065 China Graduate student of Chongqing University of Posts and Telecommunications Chongqing400065 China Professor level senior engineer of Chongqing Key Laboratory of Complex Systems and Bionic Control Chongqing University of Posts and Telecommunications Chongqing400065 China Senior engineer of State Grid Chongqing Electric Power Company Chongqing400015 China Senior engineer of Economic and Technology Research Institute State Grid Chongqing Electric Power Company Chongqing401120 China

In this paper, an objective function considering performance index and an improved gravitational search algorithm (IGSA) are proposed to optimize the parameters of fuzzy PID (FPID) controller. IGSA is obtained by combining elite strategies and the mining capability of PSO algorithm. The IGSA FPID method which integrates IGSA and FPID controller is tested in a typical two-area non-reheat system, and system responses reflect the advantages of proposed objective function and IGSA. Additionally, the proposed IGSA FPID method still has excellent effects even on the two-area multi-source system with thermal power, hydropower and gas turbines. Meanwhile, the effect of high voltage direct current (HVDC) links in suppressing fluctuations is verified. Due to the popularity of wind power, a novel three-area interconnected power system with nonlinearity connected wind turbine (WT) is designed. Under the control of IGSA FPID, the good stability and dynamic performance of mentioned three-area system are verified. Therefore, FPID controller optimized by IGSA has excellent control effects, stability and universal applicability on the different power systems with multiple area and sources. © 2022. All Rights Reserved.

关键词： Wind turbines