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Journal of Zhejiang University-Science C(Computers and Electronics) 2014年第4期15卷 275-283页

作者： Qian BI Can-jun YANG State Key Laboratory of Fluid Power Transmission and Control Zhejiang University

Exoskeleton robots and their control methods have been extensively developed to aid post-stroke rehabilitation. Most of the existing methods using linear controllers are designed for position control and are not suitable for human-machine interaction(HMI) force control, as the interaction system between the human body and exoskeleton is uncertain and nonlinear. We present an approach for HMI force control via model reference adaptive impedance control(MRAIC) to solve this problem in case of index finger exoskeleton control. First, a dynamic HMI model, which is based on a position control inner loop, is formulated. Second, the theoretical MRAC framework is implemented in the control system. Then, the adaptive controllers are designed according to the Lyapunov stability theory. To verify the performance of the proposed method, we compare it with a proportional-integral-derivative(PID) method in the time domain with real experiments and in the frequency domain with simulations. The results illustrate the effectiveness and robustness of the proposed method in solving the nonlinear HMI force control problem in hand exoskeleton.

关键词： interaction force Adaptive control Exoskeleton Human-machine interaction(HMI) Impedance

interactions between bubble and particles of key minerals of diasporic bauxite through the extended DLVO theory

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International Journal of Mining Science and Technology 2022年第1期32卷 201-214页

作者： Ningning Zhang Tian Pang Rui Han Songjiang Chen Zhen Li Yuexian Yu Zhongyu Shi Lijun Liu Jinzhou Qu Anning Zhou College of Chemistry and Chemical Engineering Xi’an University of Science and TechnologyXi’an 710054China Key Laboratory of Coal Resources Exploration and Comprehensive Utilization Ministry of Natural Resources of ChinaXi’an 710021China

The flotation of diasporic bauxite is to separate diaspore(valuable mineral)from aluminosilicate minerals(gangue minerals,mainly including kaolinite,illite and pyrophyllite),and the microscopic interaction force between the two types of minerals and air bubbles determines the separation efficiency.In this paper,based on the extended Derjaguin-Landau-Verwey-Overbeek(DLVO)theory,the van der Waals,electrostatic and hydrophobic interaction between particles of the four minerals mentioned above and air bubbles in collectorless solution were calculated first,and then diaspore and kaolinite were taken as examples to analyze the influence of various factors such as electrolyte concentration,mineral particle size,air bubble size,collector type(dodecylamine hydrochloride(DAH)and sodium oleate(NaOL))and concentration,and pulp pH on the interactions between the particles of valuable mineral and gangue minerals and air bubbles.The results showed that the total extended DLVO interactions between the four minerals and air bubbles were repulsive in most cases in collectorless solution.The increase in electrolyte concentration reduced the interaction force or even changed the direction of the force under certain circumstances.The addition of DAH and NaOL can reduce the adhesion energy barrier of kaolinitebubble and diaspore-bubble respectively.Each type of minerals exhibited a specific interface interaction response with air bubbles in each collector with different pH values.The research results have theoretical guiding significance for the optimization and directional control of diasporic bauxite flotation conditions.

关键词： Particle-bubble interaction force Diaspore Aluminosilicate minerals Extended DLVO theory

Shear Stress in MR Fluid with Small Shear Deformation in Bctlattic Structure

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Journal of Wuhan University of Technology(Materials Science) 2008年第4期23卷 532-535页

作者： LIU Lisheng RUAN Zhongwei ZHAI Pengcheng ZHANG Qingjie State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China

A theoretical model based on BCT lattice structure was developed. Resultant force in the BCT lattice structure was deduced, following the interaction force of two kinds of magnetic particles. According to empirical FroHlich-Kermelly law, the relationship between the magnetic induction and the magnetic field was discussed, and a predictive formula of shear stresses of the BCT lattice structure model was established for the case of small shear deformation. Compared with the experimental data for different particle volume fractions, the theoretical results of the shear stress indicate the effects of the saturation magnetization and the external magnetic field on the shear stress.

关键词： magnetorheological fluids （MR fluids） body-centered-tetragonal（BCT） interaction force shear stress small deformation

A New Theoretical Model about Shear Stress in Magnetorheological Fluids with Small Shear Deformation

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Journal of Wuhan University of Technology(Materials Science) 2005年第1期20卷 52-56页

作者：祝长春 State Key Laboratory of Advanced Technology for Materials Synthesis and Process ing Wuhan University of TechnologyWuhan 430070China

Based on the single-chain structure model of magnetorheological fluids, a formu la for the calculation of shear stresses was established. The interaction force of two magnetic particles in an infinite single-chain was deduced using a new theoretical model which is founded on Ampere' molecular curr ent hypothesis, dipole theory and Ampere' law. Furthermore, the resultant force on a particle was then deduced by taking into account of the action caused by al l the other particles in the single-chain. A predictive formula for shear stres ses was made corresponding to the case that MR fluids were sheared by a small an gle and the calculating results fit well on the order with the yield stresses of the commercial MR fluids.

关键词： magnetorheological fluid Ampere' molecular curre nt hypothesis dipole theory interaction force shear stress