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Dive into the research topics where Hongcai Li is active.

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Featured researches published by Hongcai Li.


Mathematical Problems in Engineering | 2014

Nonsingular Fast Terminal Sliding Mode Control with Extended State Observer and Tracking Differentiator for Uncertain Nonlinear Systems

Zhenxin He; Chuntong Liu; Ying Zhan; Hongcai Li; Xianxiang Huang; Zhili Zhang

A continuous nonsingular fast terminal sliding mode (NFTSM) control scheme with the extended state observer (ESO) and the tracking differentiator (TD) is proposed for second-order uncertain SISO nonlinear systems. The system’s disturbances and states can be estimated by introducing the ESO, then the disturbances are compensated effectively, and the ideal transient process of the system can be arranged based on TD to provide the target tracking signal and its high-order derivatives. The proposed controller obtains finite-time convergence property and keeps good robustness of sliding mode control (SMC) for disturbances. Moreover, compared with conventional SMC, the proposed control law is continuous and no chattering phenomenon exists. The property of system stability is guaranteed by Lyapunov stability theory. The simulation results show that the proposed method can be employed to shorten the system reaching time, improve the system tracking precision, and suppress the system chattering and the input noise. The proposed control method is finally applied for the rotating control problem of theodolite servo system.


Eurasip Journal on Wireless Communications and Networking | 2014

Searching algorithm of theodolite auto-focusing based on compound focal judgment

Chuntong Liu; Zhenxin He; Ying Zhan; Hongcai Li

Focusing of search judgment is one of the important parts of theodolite image measurement. Traditional hill-climbing search algorithm cannot usually focus accurately due to the interference of the evaluation function of the local extremum affected by measuring environment, such as light illumination. A compound auto-focal judgment combining image definition evaluation function and modulation transfer function (MTF) auxiliary function was introduced to improve the hill-climbing method. Definition evaluation function and MTF values of images were considered to judge the search direction together. Slanted-edge method was improved to calculate the image MTF values accurately based on the auto-selection of slanted-edge area. Lastly, the principle and implementation of the improved algorithm were given. In the theodolite auto-focusing system, the system imaging effect was validated, and different initial position and circumstances were considered using the proposed searching algorithm. The experiment results of theodolite auto-focus system show that the improved hill-climbing search algorithm can effectively eliminate the local extremum disturbance and make the system search focusing accurate and reliable.


AOPC 2017: Optoelectronics and Micro/Nano-Optics | 2017

Numerical analysis of focal depth for continuous phase filters

Hongcai Li; Yinpeng Wei; Zhili Zhang; Xiaofeng Zhao; Changqing Liu

The scalar diffractive theory for Gaussian beam has been taken into account to investigate the PSF of the focal plane. The simple slowly varying phase-only pupil filters are adopted to provide specific numerical descriptions to control the DOF of the optical systems. Simulated results of the continuous phase-only pupils in both axial and transverse directions have been presented. The impact of the structure parameters of pupil a and b on the performances of the light intensity distribution is discussed. Furthermore, some useful advices for the design of super-resolving pupils to increase DOF of the optical system based on Gaussian beam are given.


Archive | 2016

Modeling and Analyzing Electromagnetic Interference Signal in Complex Battlefield Environments

Chuntong Liu; Rongjing Wu; Zhenxin He; Xiaofeng Zhao; Hongcai Li; Pengzhi Wang

Electronic jamming is the key technology of electronic warfare, for which models and simulation are studied on noise jamming deception jamming and chaff jamming. In the noise jamming, the simulation analysis of radio frequency noise jamming is conducted and the theoretical models of other forms of noise jamming are built. The simulation analysis of RGPO is carried out in the deception jamming. In addition, theoretical modeling and simulation analysis of chaff jamming are carried out with the Monte Carlo method. Simulation results show that the models are correct and can be used to simulate the statistical characteristics of chaff jamming.


Archive | 2015

Finite Time Proportional-Integral Sliding Mode Control of Theodolite Aiming Chaotic Motor with Time Varying Parameters

Zhenxin He; Chuntong Liu; Hongcai Li; Zhili Zhang; Xianxiang Huang

In the angle measuring using theodolite, the telescope is driven by the aiming motor to sight the target automatically. The parameters of aiming motor will vary with duty conditions to bring about aiming control system chaotic, which is harmful for the aiming system and the aiming results. The aiming motor control system exist the time-varying load and the inside disturbances, the dynamic model is established and analyzed. The behavior of chaos is proved. Due to terminal sliding control with good robustness, fast dynamic response, finite time convergence and high tracking precision, The finite time proportional-integral (PI) sliding mode structure and control strategy are given, and the system stability is analyzed. The chaotic orbits of the aiming motor control system are stabilized to arbitrary chosen the fixed points and periodic orbits by means of sliding mode method. Simulation results show that finite time PI sliding mode control can realize the stability and accuracy of aiming motor control system, and overcome the negative influence of the chaos for the aiming system.


Eurasip Journal on Wireless Communications and Networking | 2016

Modeling and analyzing interference signal in a complex electromagnetic environment

Chuntong Liu; Rongjing Wu; Zhenxin He; Xiaofeng Zhao; Hongcai Li; Pengzhi Wang


Photonic Sensors | 2017

Optical Fiber Grating Vibration Sensor for Vibration Monitoring of Hydraulic Pump

Zhengyi Zhang; Chuntong Liu; Hongcai Li; Zhenxin He; Xiaofeng Zhao


2017 5th International Conference on Frontiers of Manufacturing Science and Measuring Technology (FMSMT 2017) | 2017

Research Progress of Fiber Grating Vibration Sensor

Zhengyi Zhang; Chuntong Liu; Hongcai Li; Zhenxin He; Xiaofeng Zhao


2017 2nd International Conference on Materials Science, Machinery and Energy Engineering (MSMEE 2017) | 2017

Application of Virtual Instrument in the Plunger Pump Vibration Test

Zhengyi Zhang; Chuntong Liu; Hongcai Li; Zhenxin He; Xiaofeng Zhao; Jianfeng Yu


Photonic Sensors | 2016

Research on one-piece structure target flow sensing technology based on fiber Bragg grating

Chuntong Liu; Zhengyi Zhang; Hongcai Li; Zhenxin He; Xiaofeng Zhao; Rongjing Wu

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