Shifu Xu^*, Yanan Jiang

CMES-Computer Modeling in Engineering & Sciences, Vol., , DOI:10.32604/cmes.2020.09608

Abstract Aiming at the problem that the trajectory tracking performance of redundant manipulator corresponding to the target position is difficult to optimize, the trajectory tracking method of redundant manipulator based on PSO algorithm optimization is studied. The kinematic diagram of redundant manipulator is created, to derive the equation of motion trajectory of redundant manipulator end. Pseudo inverse Jacobi matrix is used to solve the problem of manipulator redundancy. Based on the tracking ellipse of redundant manipulator, the tracking shape of redundant manipulator is determined with the overall tracking index as the second index, and the optimization method of tracking index is… More >

Hui Sheng Lim^1,*, Christopher K. H. Chin¹, Shuhong Chai¹, Neil Bose^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol., , DOI:10.32604/cmes.2020.011648

Abstract This paper presents an online AUV (autonomous underwater vehicle) path planner that employs path replanning approach and the SDEQPSO (selective differential evolution-hybridized quantum-behaved particle swarm optimization) algorithm to optimize an AUV mission conducted in an unknown, dynamic and cluttered ocean environment. The proposed path replanner considered the effect of ocean currents in path optimization to generate a Pareto-optimal path that guides the AUV to its target within minimum time. The optimization was based on the onboard sensor data measured from the environment, which consists of a priori unknown dynamic obstacles and spatiotemporal currents. Different sensor arrangements for the forward-looking sonar… More >

Ivan Paulo Canal^1,*, Manuel Martin Pérez Reimbold², Maurício de Campos²

CMES-Computer Modeling in Engineering & Sciences, Vol., , DOI:10.32604/cmes.2020.010741

Abstract An aircraft quadrotor is a complex control system that allows for great flexibility in flight. Controlling multirotor aerial systems such as quadrotors is complex because the variables involved are not always available, known, and accurate. The inclusion of payload changes the dynamic characteristics of the aircraft, making it necessary to adapt the control system for this situation. Among the various control methods that have been investigated, proportional-integralderivative (PID) control offers good results and simplicity of application; however, achieving stability and high performance is challenging, with the most critical task being tuning the controller gains. The Ziegler–Nichols (ZN) theory was used… More >

Hongyin Yang^1,2, Jiwei Zhong^1,*, Ying Wang³, Xingquan Chen², Xiaoya Bian²

CMES-Computer Modeling in Engineering & Sciences, Vol., , DOI:10.32604/cmes.2020.010936

Abstract In this paper, general interpolating isogeometric boundary node method (IIBNM) and isogeometric boundary element method (IBEM) based on parameter space are proposed for 2D elasticity problems. In both methods, the integral cells and elements are defined in parameter space, which can reproduce the geometry exactly at all the stages. In IIBNM, the improved interpolating moving leastsquare method (IIMLS) is applied for field approximation and the shape functions have the delta function property. The Lagrangian basis functions are used for field approximation in IBEM. Thus, the boundary conditions can be imposed directly in both methods. The shape functions are defined in… More >

Yuanchao Zhang¹, Zhiyuan Xia^2,*, Yujing Jiang¹, Miao Chen³, Jiankang Liu¹, Qian Yin⁴

CMES-Computer Modeling in Engineering & Sciences, Vol., , DOI:10.32604/cmes.2020.011076

Abstract Hole-like defects are very common in natural rock or coal mass, and play an important role in the failure and mechanical behaviors of rock or coal mass. In this research, multi-holed coal specimens are constructed numerically and calibrated based on UDEC-GBM models. Then, the strength, deformation and failure behavior of the porous specimens are analyzed, with consideration of hole density (P) and confining pressure (σ₃). The simulation results are highly consistent with those available experiment results, and show that the compressive strength decreases exponentially with the increasing hole density. The strength loss is mainly caused by the reduction of cohesion… More >

Xijun Zhang^*, Qirui Zhang

CMES-Computer Modeling in Engineering & Sciences, Vol., , DOI:10.32604/cmes.2020.011013

Abstract According to the time series characteristics of the trajectory history data, we predicted and analyzed the traffic flow. This paper proposed a LSTMXGBoost model based urban road short-term traffic flow prediction in order to analyze and solve the problems of periodicity, stationary and abnormality of time series. It can improve the traffic flow prediction effect, achieve efficient traffic guidance and traffic control. The model combined the characteristics of LSTM (Long Short-Term Memory) network and XGBoost (Extreme Gradient Boosting) algorithms. First, we used the LSTM model that increases dropout layer to train the data set after preprocessing. Second, we replaced the… More >

Daoyuan Yu, Shouyu Cai^*, Wenya Fan, Lan Zhang^*

CMES-Computer Modeling in Engineering & Sciences, Vol., , DOI:10.32604/cmes.2020.09936

Abstract In this study, a patch removing based Isogeometric analysis (PR-IGA) method is proposed to conduct the holed structural analysis with only one parametric domain, in which there are also no trimmed elements. The theoretical foundation of this novel patch removing approach is that any holed structure can be obtained by removing sub-patches (i.e., the holes) from an intact base patch. Since the parametric domains of these patches are all meshed by rectangular grids, the elements in the resulted holed structural parametric domain could all be untrimmed rectangles under certain mapping conditions. To achieve the special condition, a systematic technique consisting… More >

Liying Wang¹ , Zhiqiang Xu², Shuihua Wang^3,4,5,*

CMES-Computer Modeling in Engineering & Sciences, Vol., , DOI:10.32604/cmes.2020.010753

Abstract Artificial Intelligence (AI) becomes one hotspot in the field of the medical images analysis and provides rather promising solution. Although some research has been explored in smart diagnosis for the common diseases of urinary system, some problems remain unsolved completely A nine-layer Convolutional Neural Network (CNN) is proposed in this paper to classify the renal Computed Tomography (CT) images. Four group of comparative experiments prove the structure of this CNN is optimal and can achieve good performance with average accuracy about 92.07 ± 1.67%. Although our renal CT data is not very large, we do augment the training data by… More >

Zhenghao Yang, Erkan Oterkus^*, Selda Oterkus

CMES-Computer Modeling in Engineering & Sciences, Vol., , DOI:10.32604/cmes.2020.010804

Abstract In this study, a new state-based peridynamic formulation is developed for functionally graded Euler-Bernoulli beams. The equation of motion is developed by using Lagrange’s equation and Taylor series. Both axial and transverse displacements are taken into account as degrees of freedom. Four different boundary conditions are considered including pinned support-roller support, pinned support-pinned support, clamped-clamped and clamped-free. Peridynamic results are compared against finite element analysis results for transverse and axial deformations and a very good agreement is observed for all different types of boundary conditions. More >

Hao Li^1,2, Zhixia Wang^1,2, Wei Wang^1,2,*

CMES-Computer Modeling in Engineering & Sciences, Vol., , DOI:10.32604/cmes.2020.010061

Abstract Extracting nonlinear governing equations from noisy data is a central challenge in the analysis of complicated nonlinear behaviors. Despite researchers follow the sparse identification nonlinear dynamics algorithm (SINDy) rule to restore nonlinear equations, there also exist obstacles. One is the excessive dependence on empirical parameters, which increases the difficulty of data pre-processing. Another one is the coexistence of multiple coefficient vectors, which causes the optimal solution to be drowned in multiple solutions. The third one is the composition of basic function, which is exclusively applicable to specific equations. In this article, a local sparse screening identification algorithm (LSSI) is proposed… More >