Fully Adaptive Feedforward Feedback Synchronized Tracking Control for Stewart Platform Systems

Dongya Zhao,Shaoyuan Li,Feng Gao 대한전기학회 2008 International Journal of Control, Automation, and Vol.6 No.5

In this paper, a fully adaptive feedforward feedback synchronized tracking control approach is developed for precision tracking control of 6 degree of freedom (6DOF) Stewart Platform. The proposed controller is designed in decentralized form for implementation simplicity. Interconnections among different subsystems and gravity effect are eliminated by the feedforward control action. Feedback control action guarantees the stability of the system. The gains of the proposed controller can be updated on line without requiring any prior knowledge of Stewart Platform manipulator. Thus the control approach is claimed to be fully adaptive. By employing cross-coupling error technology, the proposed approach can guarantee both of position error and synchronization error converge to zero asymptotically. Because the actuators work in synchronous manner, the tracking performances are improved. The corresponding stability analysis is also presented in this paper. Finally, simulation is demonstrated to verify the effectiveness of the proposed approach.

Nonlinear sloshing in rectangular tanks under forced excitation

Zhao, Dongya,Hu, Zhiqiang,Chen, Gang,Lim, Serena,Wang, Shuqi The Society of Naval Architects of Korea 2018 International Journal of Naval Architecture and Oc Vol.10 No.5

A numerical code is developed based on potential flow theory to investigate nonlinear sloshing in rectangular Liquefied Natural Gas (LNG) tanks under forced excitation. Using this code, internal free-surface elevation and sloshing loads on liquid tanks can be obtained both in time domain and frequency domain. In the mathematical model, acceleration potential is solved in the calculation of pressure on tanks and the artificial damping model is adopted to account for energy dissipation during sloshing. The Boundary Element Method (BEM) is used to solve boundary value problems of both velocity potential and acceleration potential. Numerical calculation results are compared with published results to determine the efficiency and accuracy of the numerical code. Sloshing properties in partially filled rectangular and membrane tank under translational and rotational excitations are investigated. It is found that sloshing under horizontal and rotational excitations share similar properties. The first resonant mode and excitation frequency are the dominant response frequencies. Resonant sloshing will be excited when vertical excitation lies in the instability region. For liquid tank under rotational excitation, sloshing responses including amplitude and phase are sensitive to the location of the center of rotation. Moreover, experimental tests were conducted to analyze viscous effects on sloshing and to validate the feasibility of artificial damping models. The results show that the artificial damping model with modifying wall boundary conditions has better applicability in simulating sloshing under different fill levels and excitations.

Nonlinear sloshing in rectangular tanks under forced excitation

Dongya Zhao,Zhiqiang Hu,Gang Chen,Serena Lim,Shuqi Wang 대한조선학회 2018 International Journal of Naval Architecture and Oc Vol.10 No.5

A numerical code is developed based on potential flow theory to investigate nonlinear sloshing in rectangular Liquefied Natural Gas (LNG) tanks under forced excitation. Using this code, internal freesurface elevation and sloshing loads on liquid tanks can be obtained both in time domain and frequency domain. In the mathematical model, acceleration potential is solved in the calculation of pressure on tanks and the artificial damping model is adopted to account for energy dissipation during sloshing. The Boundary Element Method (BEM) is used to solve boundary value problems of both velocity potential and acceleration potential. Numerical calculation results are compared with published results to determine the efficiency and accuracy of the numerical code. Sloshing properties in partially filled rectangular and membrane tank under translational and rotational excitations are investigated. It is found that sloshing under horizontal and rotational excitations share similar properties. The first resonant mode and excitation frequency are the dominant response frequencies. Resonant sloshing will be excited when vertical excitation lies in the instability region. For liquid tank under rotational excitation, sloshing responses including amplitude and phase are sensitive to the location of the center of rotation. Moreover, experimental tests were conducted to analyze viscous effects on sloshing and to validate the feasibility of artificial damping models. The results show that the artificial damping model with modifying wall boundary conditions has better applicability in simulating sloshing under different fill levels and excitations.

A New TSMC Prototype Robust Nonlinear Task Space Control of a 6 DOF Parallel Robotic Manipulator

Dongya Zhao,Shaoyuan Li,Quanmin Zhu 제어·로봇·시스템학회 2010 International Journal of Control, Automation, and Vol.8 No.6

In this study, a new terminal sliding mode control (TSMC) prototype robust nonlinear task space control approach is developed for 6 degree of freedom (DOF) parallel robotic manipulators in light of TSMC principle integrated with Lyapunov redesign method. Corresponding stability analysis is presented to lay a foundation for analytical understanding in generic theoretical aspects and safe op-eration for real systems. An illustrative example of a 6 DOF parallel robot is bench tested to validate the effectiveness of the proposed approach.

Layered double hydroxide functionalized biomass carbon fiber for highly efficient and recyclable fluoride adsorption

Tao Zhang,Bencheng Zhao,Qiuyun Chen,Xiaoming Peng,Dongya Yang,Fengxian Qiu 한국응용생명화학회 2019 Applied Biological Chemistry (Appl Biol Chem) Vol.62 No.-

The removing of fluoride from water is highly desired from the viewpoint of environmental protection and sustainable development due to the adverse impacts on human and ecosystem. In this study, the hierarchical porous layered double hydroxide (LDH)/biomass carbon fiber (BCF) has been successfully fabricated by the combined sol–gel, carbonization and hydrothermal processes using sustainable bamboo fibers as raw material based on the assembly the LDH nanosheets on BCF surfaces. Structural characterization indicates that the LDH nanosheets were attached to the BCF surface via in situ crystal growth. N2 sorption measurements show that the LDH/BCF has relatively uniform accessible mesochannel size of 3.56 nm, and the surface area is as high as 39.89 m2/g. The resulting LDH/BCF exhibit a noticeable enhanced adsorption capacity for fluoride removal compared to that of Al2O3/ BCF, accompanied by 15.21 mg/g of the adsorption capacity. The presence of the high negative charge anions had negligible influence on fluoride adsorption. Importantly, recovery adsorption capacity for fluoride was obtained for LDH/BCF for 5 consecutive cycles without a significant decrease in its adsorption properties. Therefore, the current research can offer a green approach to fabricate LDH/BCF with hierarchical structures for efficient removing fluoride from water, and the fabricated LDH/BCF will be an excellent candidate for pollution control based on the synergistic effects of BCF and LDH, high adsorption properties with good reusability.

A facile hydrothermal synthesis, adsorption kinetics and isotherms to Congo Red azo-dye from aqueous solution of NiO/graphene nanosheets adsorbent

Xinshan Rong,Fengxian Qiu,Jiao Qin,Hao Zhao,Jie Yan,Dongya Yang 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.26 No.-

A series of NiO/graphene nanosheets adsorbents (NGNS) were synthesized by a facile hydrothermal method, and characterized by UV–vis, XRD, TG, TEM, HRTEM, Raman, SAED and XPS methods. The NGNS was applied to deal with wastewater solution containing Congo Red (CR); and adsorption efficiency attained 99.56% at optimum condition. The adsorption kinetic and isotherm of adsorbent toward CR were investigated. The results indicated that pseudo second-order kinetic model and the equilibrium data were well fitted by Redlich–Peterson model. The adsorbent can be separated from system effectively and easily. The prepared adsorbent has potential application for the wastewater treatment containing CR azo-dye.

Asymmetric PET Hybrid Membrane Derived from Waste PET Plastic for Personal Thermal Management Applications

Tao Zhang,Xu He,Bencheng Zhao,Dongya Yang,Fengxian Qiu 한국섬유공학회 2023 Fibers and polymers Vol.24 No.12

Controllable fabrication of wearable polyethylene terephthalate (PET) hybrid membrane derived from waste plastic is essential from the viewpoint of waste utilization and personal thermal management. Herein, this work presents an effective and versatile strategy for the fabrication of the asymmetric hybrid membrane using waste PET plastic bottles as raw material for personal thermal management applications. The obtained ZnO/Ag@PET fibrous nanofibrous membrane (ZnO/Ag@PNM) shows the asymmetrical characteristics of infrared radiation for personal thermal management: the low IR-emissivity (~ 0.39) layer (Ag layer) is facing outside to reduce the human thermal radiation, and high IR-emissivity (~ 0.96) layer (ZnO layer) is facing outward to enhance the human thermal radiation. Notably, the excellent electrical conductivity of metal coating grants the superior Joule heating for extra warmth under a low supplied voltage (2 V). Moreover, the ZnO/Ag@PNM membrane exhibits excellent antibacterial activity, flexibility, and high breathability, which shows great potential and value for wearable material in the personal thermal management application. This work not only presents a promising approach to fabricating the wearable Janus composite membrane using waste PET plastic bottles as starting materials but also provides practical potentials for thermal management and waste utilization.

Production of biodiesel from soybean oil catalyzed by attapulgite loaded with C4H5O6KNa catalyst

Fengxian Qiu,Bin Ye,Yihuai Li,Chuanjia Sun,Zhenyu Zhao,Teng Ma,Dongya Yang 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.7

Biodiesel is a green, safe, renewable alternative fuel, which is of great significance to solving the problem of energy shortage and environmental pollution. A series of solid base catalysts were prepared with the support of attapulgite (ATP), the load of C4H5O6KNa by impregnation method, and were used to catalyze transesterification of soybean oil with methanol to biodiesel. The activities of prepared catalysts were investigated compared to pure ATP. The optimal conditions for the catalyst preparation were investigated: molar ratio of Na : ATP was 1.7 : 1 and calcination temperature was 400 oC. The prepared catalysts were characterized by several techniques such as Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, N2 adsorption-desorption measurements,X-ray diffraction and the Hammett indicator method. The prepared solid base catalyst can be separated from reaction system effectively and easily. The effects of the molar ratio of methanol to oil, reaction temperature and amount of catalyst on the biodiesel yield were investigated. The experimental results showed that a 22 : 1 molar ratio of methanol to oil, 10.0% of catalyst amount, 65 oC of reaction temperature and 3.0 h of reaction time gave the best results. The catalyst has longer lifetime and maintained sustained activity after being used for five cycles.

Removal of malachite green from the contaminated water using a water-soluble melamine/maleic anhydride sorbent

Xinshan Rong,Fengxian Qiu,Jiao Qin,Jie Yan,Hao Zhao,Dongya Yang 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

A novel water-soluble adsorbent (S-Me/MA) was prepared from melamine and maleic anhydride by two steps. The structure of material was characterized by FT-IR spectroscopy, SEM, and 1H NMR. The S-Me/MA was applied to deal with wastewater solution containing malachite green (MG). The influences of adsorbent dose, temperature, pH and contact time were investigated. At the same time, the adsorption kinetic and isotherm of S-Me/MA toward malachite green were investigated. The results indicated that the adsorption of malachite green was in line with pseudo-second order kinetics equation. Langmuir isotherm equation can be a fine description of the removal process.