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Prediction of landslide displacement based on improved grey wolf optimizer and support vector regression
Shuai REN, Yuanfa JI, Xiyan SUN, Zhaochuan WEI, Zian LIN
Journal of Computer Applications    2024, 44 (3): 972-982.   DOI: 10.11772/j.issn.1001-9081.2023030331
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To address the issues of difficult prediction of landslide displacement and difficulty in selecting influencing factors, a model combining Double Moving Average (DMA), Variational Modal Decomposition (VMD), Improved Gray Wolf Optimizer (IGWO) algorithm and Support Vector Regression (SVR) was proposed for landslide displacement prediction. Firstly, DMA was used to extract the trend and periodic terms of landslide displacement, and polynomial fitting was used to predict the trend term. Secondly, the influencing factors of the landslide periodic term were classified, and VMD was used to decompose the original factor sequence to obtain the optimal sequence. Then, a grey wolf optimizer algorithm combining SVR with an improved Circle-based multi-tactic, called CTGWO-SVR (Circle Tactics Grey Wolf Optimizer with SVR), was proposed to predict the landslide periodic term. Finally, the cumulative displacement prediction sequence was obtained using a time series additive model, and the model was evaluated using post validation difference verification and small probability error in grey prediction. Experimental results show that compared with GA (Genetic Algorithm)-SVR and GWO-SVR models, CTGWO-SVR has higher prediction accuracy with a fitting degree of 0.979, and the Root Mean Square Error (RMSE) reduces by 51.47% and 59.25%, respectively. The model evaluation accuracy is level one, which can meet the real-time and accuracy requirements of landslide prediction.

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Control method of quadrotor UAV with manipulator based on expert PID
Bao CHEN, Zupeng ZHOU, Huan WEI, Yanzhao LYU, Zhicheng SUI
Journal of Computer Applications    2022, 42 (8): 2637-2642.   DOI: 10.11772/j.issn.1001-9081.2021060975
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Compared with the Unmanned Aerial Vehicle (UAV) without manipulator, the UAV with manipulator has large deviation in the flight trajectory and is more difficult to control stably. In order to solve the precise trajectory control problem of UAV with manipulator, a control method of quadrotor UAV with manipulator based on expert PID was proposed. Firstly, the manipulator was equipped to the UAV and the two was considered as a whole, and the kinematics and dynamics system models of UAV with manipulator was established through Lagrange equation. Secondly, an expert PID controller was designed to control the stability of the system. Thirdly, the trajectory planning of the manipulator of UAV with manipulator was carried out by using quintic polynomial. Finally, the effectiveness of expert PID control method for the stability control of UAV with manipulator is verified by simulation. The experimental results show that compared with conventional PID control, the proposed control method based on expert PID improves the response speed of the system and can effectively suppress external disturbances. This method can track the trajectory of the manipulator stably under the action, and has good immunity and robustness.

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