Variable Parameter Sliding Controller Design for Vehicle Brake with Wheel Slip

Hong Liang,Kil To Chong 대한기계학회 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.11

In this paper, a 4-wheel vehicle model including the effects of tire slip was considered, along with variable parameter sliding control, pushrod force as the end control parameter, and an antilock sliding control, in order to improve the performance of the vehicle longitudinal response. The variable sliding parameter is made to be proportional to the square root of the pressure derivative at the wheel, in order to compensate for large pressure changes in the brake cylinder. A typical tire force-relative slip curve for dry road conditions was used to generate an analytical tire force-relative slip function, and an antilock sliding control process based on the analytical tire force-relative slip function was used. A retrofitted brake system, with the pushrod force as the end control parameter, was employed, and an average decay function was used to suppress the simulation oscillations. Simulation results indicate that the velocity and spacing errors were slightly larger than the results that without considering wheel slip effect, the spacing errors of the lead and follower were insensitive to the adhesion coefficient up to the critical wheel slip value, and the limit for the antilock control on non-constant adhesion road condition was determined by the minimum of the equivalent adhesion coefficient.

Infinite horizon optimal control problems of backward stochastic delay differential equations in Hilbert spaces

Hong Liang,Jianjun Zhou 대한수학회 2020 대한수학회보 Vol.57 No.2

This paper investigates infinite horizon optimal control problems driven by a class of backward stochastic delay differential equations in Hilbert spaces. We first obtain a prior estimate for the solutions of state equations, by which the existence and uniqueness results are proved. Meanwhile, necessary and sufficient conditions for optimal control problems on an infinite horizon are derived by introducing time-advanced stochastic differential equations as adjoint equations. Finally, the theoretical results are applied to a linear-quadratic control problem.

Effects of Bath Temperature on Electrodeposited Permanent Magnetic Co-Pt-W(P) Films

Hongliang Ge*,Qiong Wu,Guoying Wei,Xinyan Wang,Qiaoying Zhou 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.12

The effects of bath temperature on electrochemical behavior, alloy composition, crystallographic structure, morphology and the magnetic properties of electrodeposited Co-Pt-W(P) films were investigated. Electro- chemical studies show that alloy electrodeposition has been shifted to more positive potentials and the critical time for nucleation decreased as electrolyte temperature increased. As the temperature increased from 40 oC to 80 oC, tungsten content in the deposit increased, while phosphorus content decreased. The films deposited at T = 40 oC exhibited soft magnetic properties. However, electrodeposited at T = 70 oC, the films exhibited hard magnetic properties. It is also demonstrated that higher temperature more than 70 oC could weaken hard magnetic properties. XRD results indicated that the deposits obtained at 50 oC-70 oC showed enhancement of [00.1] P.O. (preferred orientation) with the bath temperature, which resulted in the stronger perpendicular magnetic anisotropy.

A tunable dynamic vibration absorber for unbalanced rotor system

Hongliang Yao,Tongzhao Wang,Bang-chun Wen,Baijun Qiu 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.4

A tunable dynamic vibration absorber for unbalanced rotor system which is made up of coil springs and magnetic spring is presented. The structure of the absorber is introduced and the stiffness tuning mechanism of the magnetic spring is explained. A finite element model of the rotor-absorber system was built and the influencing factors to the appearance of the absorber were studied numerically. Finally, experiments were carried out to verify the numerical results, and PID control strategy was tested. The numerical and experimental results show that the present absorber is effective for vibration suppression of an unbalanced rotor system, and the control strategy is effective.

Evaluation of Solar Temperature Field under Different Wind Speeds for Shanghai 65 m Radio Telescope

Hongliang Qian,Deshen Chen,Feng Fan,Ye Liu,Shi-zhao Shen 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.2

The Shanghai 65 m radio telescope is currently the largest full range rotatable radio telescope in Asia. Gravity, wind and temperature are the three main factors which may have a bad effect on the reflector’s surface precision. To study the effect of the thermal deformation caused by daily non-uniform temperature fields on the surface precision of the main reflector, both the temperature field and its effect were studied in detail for two typical days (January 15th and July 15th). The method to simulate temperature fields was studied initially, considering heat conduction, solar radiation, shadowing, air convection, sky radiation and ground radiation. Then, an integral parametric thermal finite element model (FEM) of the telescope was established using the ANSYS thermal analysis module. Finally, the effect of non-uniform temperature fields on the surface precision of the main reflector was estimated in terms of the Root Mean Square (RMS) deformation based on temperature transient analysis. The proposed methods and conclusions drawn can provide valuable information for thermal design, thermal monitoring and thermal control of the Shanghai 65 m radio telescope and other similar giant antenna structures.

Influences of Pump Spot Radius and Depth of Focus on the Thermal Effect of Tm:YAP Crystal

Hongliang Zhang,Ya Wen,Lin Zhang,Zhen Fan,Jinge Liu,Chunting Wu 한국광학회 2019 Current Optics and Photonics Vol.3 No.5

The thermal effect and the light output of a laser crystal under different pumping depths were reported., Based on the thermal model of a single-ended pumped Tm:YAP crystal, the thermal stress coupled model used Comsol to theoretically calculate the effect of changing the pump spot size and pump depth on crystal heat distribution and stress distribution. The experimental results showed that the laser output power first increased and then decreased with increasing pump spot size. As the depth of focus increased, the laser output power first increased and then decreased. The experimental results were consistent with the theoretical simulation results. The theory of pump spot radius and depth of focus in this paper provided an effective simulation method for mitigating thermal effects, and provided theoretical supports for laser crystals to obtain higher laser output power.

The self-excited vibrations of an axially retracting cantilever beam using the Galerkin method with fitted polynomial basis functions

Hongliang Hua,Zhenqiang Liao,Xiangyan Zhang 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.1

In the present study, the self-excited vibrations of an axially retracting beam under gravity is investigated. A GFB method is presented to discretize the system energy functions, in which the orthogonality relationships between the basis functions are needless. In this way, the motion equations can be derived in a much simpler way of matrix. The presented method and the derived motion equations are validated by comparing the computed results with which from previous literature. Based on the computed dynamic responses, the effect of gravity on beam dynamic behavior is investigated. An interesting phenomenon of self-excited vibration is observed as the beam retracts with a certain axial speed. Finally, the effects of retracting speed, structural damping and static tip deflection on self-excited vibration are investigated.

Dynamic analysis of an axially moving beam subject to inner pressure using finite element method

Hongliang Hua,Ming Qiu,Zhenqiang Liao 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.6

A dynamic model of an axially moving flexible beam subject to an inner pressure is present. The coupling principle between a flexible beam and inner pressure is analyzed first, and the potential energy of the inner pressure due to the beam bending is derived using the principle of virtual work. A 1D hollow beam element contain inner pressure is established. The finite element method and Lagrange’s equation are used to derive the motion equations of the axially moving system. The dynamic responses are analyzed by Newmark-β time integration method. Based on the computed dynamic responses, the effects of inner pressure on beam dynamics are discussed. Some interesting phenomenon is observed.

DMRUT-MCDS: Discovery Relationships in the Cyber-Physical Integrated Network

Hongliang Lu,지아농챠오,Weiping Zhu,Xianlong Jiao,Shaohe Lv,Xiaodong Wang 한국통신학회 2015 Journal of communications and networks Vol.17 No.6

In recent years, we have seen a proliferation of mobilenetwork- enabled smart objects, such as smart-phones and smartwatches, that form a cyber-physical integrated network to connect the cyber and physical worlds through the capabilities of sensing, communicating, and computing. Discovery of the relationship between smart objects is a critical and nontrivial task in cyber-physical integrated network applications. Aiming to find the most stable relationship in the heterogeneous and dynamic cyber-physical network, we propose a distributed and efficient relationship-discovery algorithm, called dynamically maximizing remaining unchanged time with minimum connected dominant set (DMRUT-MCDS) for constructing a backbone with the smallest scale infrastructure. In our proposed algorithm, the impact of the duration of the relationship is considered in order to balance the size and sustain time of the infrastructure. The performance of our algorithm is studied through extensive simulations and the results show that DMRUT-MCDS performs well in different distribution networks.

Ultrasonic Synthesis of Au/AgCl Hybrid Cubes and Their Evolution Under Electron Beam Irradiation

Hongliang Cao,Xiaoli Miao,Mengqin Zhu,Chang Li,Feifei Wei,Xin Chen 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.6

The utilization of ultrasound offers a facile tool for the synthesis of Au/AgCl hybrid particles. We have obtained the architectures of Au nanoparticles on AgCl sub-micrometer cubes by simply ultrasonic irradiating their precursors in ethylene glycol (EG). The formation process of Au/AgCl hybrid particles in the reaction solution has been studied based on the optical absorption spectra and the scanning electron microscope (SEM) images of the particles obtained at different ultrasonic irradiation stages. The dynamic changes of Au/AgCl hybrid particles under electron beam irradiation have been investigated in both SEM and in situ liquid cell transmission electron microscope (TEM). Hollow Au/AgCl hybrid particle structures have been obtained under the electron beam irradiation in liquid, with the cuboid contour shape preserved.