Dynamic Path Planning Based on Fuzzy and Behavior Control Idea

Lei Yanmin,Xing Xiaoxue,Feng Zhibin,Guan Xiuli,Du Limin 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.12

In order to solve dynamic path planning problem of multi-robot systems in unknown dynamic environment, a kind of method based on fuzzy and behavior control idea was proposed in this paper. This method designs two fuzzy controllers, which are danger degree fuzzy controller and velocity fuzzy controller. They took fully into account the position and the velocity of the obstacle and the azimuth of the target. Fuzzy rules were designed based on behavior control idea and which reflected move-to-goal behavior, avoid-obstacle behavior and follow-obstacle behavior. The experimental results show that the proposed method is feasible and valid and is suitable for the dynamic and complicated environment in particularly.

Numerical Simulation of Site Deformation Induced by Shield Tunneling in Typical Upper-Soft-Lower-Hard Soil-Rock Composite Stratum Site of Changchun

Liyun Li,Xiuli Du,Jing Zhou 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.10

In China, with the rapid development of subway construction, the site deformation induced by subway construction is an interesting and hot issue in civil engineering. Focusing on the mechanism and characteristics of site deformation induced by parallel shield tunnel construction in typical soil-rock composite strata of Changchun region, and relying on the subway tunnel between Northeast Normal University Station and Gongnong Square Station, which belongs to the Changchun Metro Line 1, the tunnel construction process is simulated using FLAC3D software. In this paper, the numerical modeling and parameters for shield tunneling are described in detail, and the mechanism and characteristics of site deformation induced by shield tunneling are discussed systematically. Furthermore, the influence of construction parameters on site deformation, including construction sequence, tunnel spacing and earth chamber pressure, are studied. The results can provide reference for similar projects in the future.

Application of an extended Bouc-Wen model for hysteretic behavior of the RC structure with SCEBs

Huihui Dong,Qiang Han,Xiuli Du 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.71 No.6

The reinforced concrete (RC) structures usually suffer large residual displacements under strong motions. The large residual displacements may substantially reduce the anti-seismic capacity of structures during the aftershock and increase the difficulty and cost of structural repair after an earthquake. To reduce the adverse residual displacement, several self-centering energy dissipation braces (SCEBs) have been proposed to be installed to the RC structures. To investigate the seismic responses of the RC structures with SCEBs under the earthquake excitation, an extended Bouc-Wen model with degradation and self-centering effects is developed in this study. The extended model realized by MATLAB/Simulink program is able to capture the hysteretic characteristics of the RC structures with SCEBs, such as the energy dissipation and the degradation, especially the self-centering effect. The predicted hysteretic behavior of the RC structures with SCEBs based on the extended model, which used the unscented Kalman filter (UKF) for parameter identification, is compared with the experimental results. Comparison results show that the predicted hysteretic curves can be in good agreement with the experimental results. The nonlinear dynamic analyses using the extended model are then carried out to explore the seismic performance of the RC structures with SCEBs. The analysis results demonstrate that the SCEB can effectively reduce the residual displacements of the RC structures, but slightly increase the acceleration.

Radian of the vault influencing the seismic performances of straight wall arch underground structures

Chao Ma,Dechun Lu,Chengzhi Qi,Xiuli Du 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.78 No.5

Great efforts have been conducted to investigate the seismic performances of the arch and rectangular underground structures, however, the differences between seismic responses of these two types of underground structures, especially the vault radian influencing the seismic responses of arch structures are not clarified. This paper presents a detailed numerical investigation on the seismic responses of arch underground structures with different vault radians, and aims to illustrate the rule that vault radian affects the seismic responses of underground structures. Five arch underground structures are built for nonlinear soil-structure interaction analysis. The internal forces of the structural components of the underground structures only under gravity are discussed detailedly, and an optimum vault radian for perfect load-carrying functionality of arch underground structures is suggested. Then the structures are analyzed under seven scaled ground motions, amounting to a total of 35 dynamic calculations. The numerical results show that the vault radian can have beneficial effects on the seismic response of the arch structure, compared to the rectangular underground structures, causing the central columns to suffer smaller axial force and horizontal deformation. The conclusions provide some directive suggestions for the seismic design of the arch underground structures.

Seismic resistant design of highway bridge with multiple-variable frequency pendulum isolator

Xu Liang,Jianian Wen,Qiang Han,Xiuli Du 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.28 No.2

Multiple variable frequency pendulum isolator (MVFPI) has been recently developed as a superior alternative to the traditional friction pendulum bearing (FPB) especially for the seismic isolation in near-fault regions. The MVFPI is characterized by its variable frequency and self-adaptability, which are achieved by piecewise function of sliding surface and shape memory alloy (SMA). The objective of this study is to propose the design algorithm of the MVFPIs in highway bridge as an extension of the direct displacement-based design (DDBD) framework. The nonlinearities of the structural components are taken into account in the design procedure, and the corresponding damage states satisfy the two-stage design philosophy. The accuracy and robustness of the design procedure are verified by an isolated four-span highway bridge through nonlinear time history (NLTH) analyses. The analytical results indicate that the proposed design procedure can predict the profile of deck displacement and amplitude, as well as the damage states of the piers. From statistic aspect, the fragility analyses illustrate that the bridge isolated by MVFPIs exhibits better seismic performance than that of the bridge isolated by FPBs.

Artificial-Neural-Network-Based Mechanical Simulation Prediction Method for Wheel-Spoke Cable Truss Construction

Zhansheng Liu,Antong Jiang,Wenyuan Shao,Anshan Zhang,Xiuli Du 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.3

Cable force monitoring is an important step in cable truss structural health monitoring. Considering cost eff ectiveness, the accuracy and quality of safety assessments depend primarily on the usage of reasonable cable monitoring programs. Many monitoring methods have been proposed to design the cable truss structure. The emergence of artifi cial neural network (ANN) models has resulted in improved predictive abilities. In this study, an ANN-based model is used to estimate parameter changes in static and prestress loss tests during the construction of a cable truss. The fi nite element model data of 243 cases are analysed by ANSYS and MATLAB. Analysis results indicate the excellent prediction performance as well as high accuracy and generalization of the proposed ANN-based model. Furthermore, the successfully trained ANN-based model is used to predict new cases. As an alternative to fi nite element analysis and physical test, the proposed model can guide the static loading of the spoke cable truss structure and thus allow the safe usage of the structure during service.

PSO-based Machine Learning Methods for Predicting Ground Surface Displacement Induced by Shallow Underground Excavation Method

Fanchao Kong,Tao Tian,Dechun Lu,Bing Xu,Weipeng Lin,Xiuli Du 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.11

Four hybrid intelligent methods are developed to predict the maximum ground surface settlement (Smax) induced by shallow underground excavation method (SUEM). Particle swarm optimization (PSO) algorithm with k-fold cross validation is used to determine the optimal hyperparameters or random parameters in the four machine learning (ML) methods, namely that, back-propagation neural network (BPNN), extreme learning machine (ELM), support vector regression (SVR) and random forest (RF). 100 field engineering samples are collected from published papers. In each data sample, the effect of stratum mechanical conditions, tunnel geometric parameters and construction parameters on Smax is considered. Correlation laws among parameters are investigated through Pearson correlation coefficient, data distribution histogram and correlation confidence ellipse. The performance of four PSO-based ML methods is comprehensively compared by fitness function, time cost and prediction accuracy in the training and test processes. PSO-RF outperforms PSO-SVR, PSO-ELM and PSO-BPNN in the prediction accuracy for Smax owing to larger R2, smaller MAE and RMSE. Calculation time that the optimal hyperparameters are determined is the fastest for PSO-RF, and PSO-ELM has the smallest fitness function. The prediction performance of PSO-RF method for construction parameters is also discussed. This work can provide theoretical guidance for design and construction of SUEM.