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Publication
Featured researches published by Hongcai Li.
Mathematical Problems in Engineering | 2014
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
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
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
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
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
Chuntong Liu; Rongjing Wu; Zhenxin He; Xiaofeng Zhao; Hongcai Li; Pengzhi Wang
Photonic Sensors | 2017
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
Zhengyi Zhang; Chuntong Liu; Hongcai Li; Zhenxin He; Xiaofeng Zhao
2017 2nd International Conference on Materials Science, Machinery and Energy Engineering (MSMEE 2017) | 2017
Zhengyi Zhang; Chuntong Liu; Hongcai Li; Zhenxin He; Xiaofeng Zhao; Jianfeng Yu
Photonic Sensors | 2016
Chuntong Liu; Zhengyi Zhang; Hongcai Li; Zhenxin He; Xiaofeng Zhao; Rongjing Wu