Trajectory Planning of Rail Inspection Robot Based on an Improved Penalty Function Simulated Annealing Particle Swarm Algorithm

Ruoyu Xu,Jianyan Tian,Jifu Li,Xinpeng Zhai 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.10

To ensure the smooth operation of each joint and shorten the joint movement time of a rail inspection robot, a trajectory planning method based on time optimization with a penalty function is proposed. According to the Denavit-Hartenberg (D-H) model of the inspection robot, a kinematic solution is found, and the trajectory of each joint is generated using a mixed polynomial interpolation algorithm. Taking time optimization as the standard, the traditional particle swarm algorithm cannot handle complex constraints, easily falls to local optimum solutions, and has a slow convergence speed. An improved simulated annealing particle swarm algorithm with a penalty function (IPF-SA-PSO) is proposed to optimize the trajectory generated by the mixed polynomial interpolation algorithm. The simulation results show that the proposed algorithm, compared with the mixed polynomial interpolation method, can limit the angular velocity and reduce the running time of each manipulator joint. The two algorithms are experimentally verified based on a rail inspection robot, and the results show that after adopting the optimization algorithm, the angular velocity of each joint is within the angular velocity limit, the run time is shorter, and the operation is smoother, which indicates the effectiveness of the proposed algorithm. The proposed algorithm can optimize the robot running time, improve the smoothness, and be applied to the fields of the automatic tracking of abnormal targets and video acquisition.

A nonlinear friction-cohesive model for characterizing mode II fracture of laminated composites

Ruoyu Li,Chaocan Cai,Zhonghai Xu,Xiaocan Zou,Chunxing Hu,Xiaodong He 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.5

In this paper, the Coulomb friction is incorporated into the exponential cohesive law, so a nonlinear friction-cohesive model combining sliding friction and interfacial debonding is developed to characterize the mechanical responses of mode II fracture. This model can well simulate the load-displacement curve of ENF test, after properly calibrating the parameters through the experimental data available in the literature. Then, a parametric study to investigate the effects of interfacial parameters on the load-displacement curves of ENF test has been carried out. The results show that, compared with the bi-linear cohesive model and exponential cohesive model, the proposed model is closer to the experimental data. Friction parameters will affect the initial delamination stage and stable delamination stage of ENF test, and interfacial characteristic lengths and interfacial shear strength will affect the peak load of ENF test.

Severe Cutaneous Adverse Reactions: A Single-Center Retrospective Study of 173 Patients in China

( Zhongyi Xu ),( Jie Shen ),( Yiwen Yang ),( Ruoyue Yuan ),( Leihong Flora Xiang ),( Chengfeng Zhang ) 대한피부과학회 2019 Annals of Dermatology Vol.31 No.5

Background: Severe cutaneous adverse reactions (SCAR) to drugs are a crucial public health issue and the use of systemic corticosteroids in SCAR has been controversial. Objective: To analyze clinical features, causative drugs, treatment, outcomes, and prognostic factors of SCAR in the case-series of 173 patients, and add more information to the debate of using systemic corticosteroids in SCAR management. Methods: A retrospective study of 173 SCAR patients diagnosed with drug reaction with eosinophilia and systemic symptoms (DRESS), Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) or acute generalized exanthematous pustulosis (AGEP) at a tertiary care institution in China between January 2014 and December 2017 was conducted. Results: Of 173 patients, allopurinol, carbamazepine, and antibiotics are the most frequently implicated drugs for DRESS (40.4%), SJS/TEN (26.0%), and AGEP (40.0%) respectively. Moreover, there is a strongly negative correlation between early corticosteroids use and the progression (p=0.000) and severity (p=0.01) of skin lesions. However, there is no association between early corticosteroids use and the mortality of SCAR (odds ratio: 1.01, 95% confidence interval: 0.95∼1.08). In addition, lymphadenopathy, eosinophilia, and interval from onset to corticosteroids treatment were correlated with SCAR prognosis. Conclusion: Prompt short-course systemic corticosteroids use is associated with early-stage skin lesions remission without influencing the disease mortality. Lymphadenopathy and eosinophilia were the independent poor prognostic factors of SCAR. (Ann Dermatol 31(5) 545∼ 554, 2019)

Idle Slots Skipped Mechanism based Tag Identification Algorithm with Enhanced Collision Detection

( Jian Su ),( Ruoyu Xu ),( Shiming Yu ),( Baowei Wang ),( Jiuru Wang ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.5

In this article, a new Aloha-based tag identification protocol is presented to improve the reading efficiency of the EPC C1 Gen2-based UHF RFID system. Collision detection (CD) plays a vital role in tag identification process which determines the efficiency of anti-collision protocols since most Aloha-based protocols optimize the incoming frame length based on the collisions in current frame. Existing CD methods are ineffective in identifying collision, resulting in a degradation of identification performance. Our proposed algorithm adopts an enhanced CD (ECD) scheme based on the EPC C1 Gen2 standard to optimize identification performance. The ECD method can realize timely and effective CD by detecting the pulse width of the randomly sent by tags. According to the ECD, the reader detects the slot distribution and predicts tag cardinality in every collision slot. The tags involved in each collision slot are identified by independently assigned sub-frames. A large number of numerical results show that the proposed solution is superior to other existing anti-collision protocols in various performance evaluation metrics.

Redundant rule Detection for Software-Defined Networking

( Jian Su ),( Ruoyu Xu ),( Shiming Yu ),( Baowei Wang ),( Jiuru Wang ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.6

The emergence of Software Defined Networking (SDN) overcomes the limitations of traditional networking architectures. There are some advantages in SDN which are centralized global network view, programmability, and separation of the data plane and control plane. Due to the limitation of data plane storage capacity in SDN, it is necessary to process the redundancy rules of switch. In this paper, we propose a method for active detection and processing of redundant rules. We use the result generated by the customized probe package to detect redundant rules. And by checking the forwarding behavior of probe packets in the data plane, the redundancy rules are further processed. Furthermore, in order to quickly check the dynamic networks, we propose an incremental algorithms for rapidly evolve the network strategies. We conduct simulation experiments on Matlab to verify the feasibility of the algorithm. The influence of some parameters on the result are discussed.

Experimental and theoretical studies on SHS column connection with external stiffening ring under static tension load

Bin Rong,Guangchao You,Ruoyu Zhang,Xu Ma,Xinxin Quan 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.28 No.2

In order to investigate mechanical properties in the core area of Square Hollow Section(SHS) column connection with external stiffening ring, four specimens were tested under the static tension load. The failure modes, load-displacement curves and strain distribution were analyzed to study the mechanical properties and the load transfer mechanism of the core area of connections. The connections behave good ductility and load-bearing capacity under the static tension load. Parametric analysis was also conducted, in which the thickness of steel tube, extended width and thickness of the stiffening ring were considered as the parameters to investigate the effects on mechanical properties of the connections. Based on the experimental results, an analytical method for the bearing capacity of connection with external stiffening ring under the static tension load was proposed. The theoretical results and the experimental results are in good agreement, which indicates that the theoretical calculation method of the bearing capacity is advisable.

The compressive behavior of CFRP laminates with delamination of different shapes using numerical and experimental approaches

Chunxing Hu,Yujiao Bai,Zhonghai Xu,Ruoyu Li,Rongguo Wang,Xiaodong He 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.9

Composite laminates often produce delamination due to a series of factors during the manufacture and service process. In order to research the effect of containing oblique elliptical and circular initial delamination damage on the compressive strength of composite laminates, numerical and experimental methods are used in this paper. Finite element models (FEMs) and the progressive damage subroutine USDFLD are developed to predict the damage initiation and extension behavior of the intralaminar of the laminate. Interlaminar damage is predicted based on cohesive zone models (CZM). At the same time, four compression tests containing different initial delamination damage are performed. The results show that experimental measurements of compression tests concur with the numerical predictions and validate the FEMs. The strength and stiffness of the specimens gradually decrease with the increase of the initial delamination area. It reveals that, for the compression process, the delamination damage extends from the edge of the initial damage to the surroundings. The bearing capacity of the composite laminates is mainly determined by the material properties of the fibers and matrix, rather than the initial delamination.