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6 results on '"Li, Aitang"'

4. Stress Inversion and Fault Instability in the Source Region of the 2021 (M S 5.0) Yingjiang Earthquake.

Author

Li, Aitang, Xie, Chaodi, Ji, Yingfeng, Zhu, Weiling, Xu, Yan, Wang, Guangming, and Zhao, Xiaoyan

Subjects
TSUNAMI warning systems, EARTHQUAKE aftershocks, EARTHQUAKES, LOGICAL prediction
Abstract

Featured Application: Resource and environmental effects of the Tibetan Plateau. On 12 June 2021, an earthquake with MS 5.0 occurred in Yingjiang, adjacent to eastern Myanmar, where seismic activity is frequent due to plate collision. To explore the mechanism of this earthquake, the regional stress field of the Yingjiang zone was inverted using the focal mechanisms of 187 historical earthquakes in this area. Furthermore, based on the obtained orientation of the principal stress axes and the stress shape ratio, the fault slip tendency (Ts) was also estimated to evaluate fault instability in the study area. The stress variation results show that the diffusion and migration of the aftershocks suggested strike–slip-type stress accumulation in Yingjiang with a principal compressive stress axis direction-oriented NNE–SSW. Fault slip tendency results show that the seismogenic faults feature strikes within the ranges of 40~80° and 110~150° and dips of 60~90° and exhibit enhanced stress coupling. The distribution of the aftershock sequence is conjectured to have a high correlation with local fluid migration and was likely controlled by the hydrated rock-induced ruptures of the stressed fault systems near the source region. This study provides insights into potential earthquake risks in this region. [ABSTRACT FROM AUTHOR]

Published
2023
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5. Design of Hover Flying Adaptive PD Controller for Four Rotor Unmanned Aerial Vehicle

Author

Nie Yan, Cao Xiaowen, Yuhang Yang, Ye Zhang, Fan Dan, and Li Aitang

Subjects
Lyapunov function, Vehicle dynamics, symbols.namesake, Estimation theory, Computer science, Control theory, Rotor (electric), law, symbols, PID controller, Reference model, law.invention, Compensation (engineering)
Abstract

An adaptive PD controller design method based on model reference is proposed, which is used to control the suspension of the four rotorcraft with variable quality. The reference model is obtained by approximating the attitude angle of the hovercraft by the kinetic equation of the UAV, and a second order system is selected according to the reference model which is similar to the actual system and has the expected dynamic characteristics. Based on the method of Lyapunov’s stability theory, the parameters of the controller are determined by the error between the output of the controlled object and the output of the reference model. When the controlled object parameter changes, the adaptive mechanism adjusts the PD controller by parameter estimation so that the estimated value of the controlled object parameter can always track its actual value. The adaptive controller is compared with the conventional PD controller and the PD controller with speed limit compensation in the simulation experiment. The results show that the control signal of the controller is smaller than that of the conventional PD controller. It is faster and more stable than the PD controller with the speed limit compensation. It has better control effect on the hover of quadrotor drone.

Published
2020

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