A New LuGre Friction Model for MR-9000 Type MR Damper

Author(s):  
Fan Yang ◽  
Ramin Sedaghati ◽  
Ebrahim Esmailzadeh

This paper presents a new hysteresis model, based on the LuGre friction model, to analyze the dynamic behavior of large-scale Magneto-Rheological (MR) damper (MR-9000 type MR-damper [1]) accurately and efficiently. The gradient based optimization technique and the least square method will be utilized to identify the modal parameters. The dynamic behavior of MR-damper under different types of excitation and input current have been predicted using the proposed model and then compared with those predicted using modified Bouc-Wen model to verify the validity of the proposed model.

Author(s):  
Yanto Mualim ◽  
Fathi H. Ghorbel ◽  
James B. Dabney

A novel approach to better model nanomanipulation of a nanosphere laying on a stage via a pushing scheme is presented. Besides its amenability to nonlinear analysis and simulation, the proposed model is also effective in reproducing experimental behaviors commonly observed during AFM-type nanomanipulation. The proposed nanomanipulation model consists of integrated subsystems that are identified in a modular fashion. The subsystems consistently define the dynamics of the nanomanipulator tip and nanosphere, interaction forces between the tip and the nanosphere, friction between the nanosphere and the stage, and the contact deformation between the nanomanipulator tip and the nanosphere. The main feature of the proposed nanomanipulation model is the Lund-Grenoble (LuGre) dynamic friction model that reliably represents the stick-slip behavior of atomic friction experienced by the nanosphere. The LuGre friction model introduces a new friction state and has desirable mathematical properties making it a well-posed dynamical model that characterizes friction with fidelity. The proposed nanomanipulation model facilitates further improvement and extension of each subsystem to accommodate other physical phenomena that characterize the physics and mechanics of nanomanipulation. Finally, the versatility and effectiveness of the proposed model is simulated and compared to existing models in the literature.


Meccanica ◽  
2021 ◽  
Author(s):  
Gábor Csernák ◽  
Gábor Licskó

AbstractThe responses of a simple harmonically excited dry friction oscillator are analysed in the case when the coefficients of static and kinetic coefficients of friction are different. One- and two-parameter bifurcation curves are determined at suitable parameters by continuation method and the largest Lyapunov exponents of the obtained solutions are estimated. It is shown that chaotic solutions can occur in broad parameter domains—even at realistic friction parameters—that are tightly enclosed by well-defined two-parameter bifurcation curves. The performed analysis also reveals that chaotic trajectories are bifurcating from special asymmetric solutions. To check the robustness of the qualitative results, characteristic bifurcation branches of two slightly modified oscillators are also determined: one with a higher harmonic in the excitation, and another one where Coulomb friction is exchanged by a corresponding LuGre friction model. The qualitative agreement of the diagrams supports the validity of the results.


2011 ◽  
Vol 204-210 ◽  
pp. 2196-2201
Author(s):  
Yan Tao Jiang ◽  
Si Tian Chen ◽  
Cheng Hua Li

In this paper, the fast multipole virtual boundary element - least square method (Fast Multipole VBE - LSM) is proposed and used to simulate 2-D elastic problems, which is based on the fast multipole method (FMM) and virtual boundary element - least square method (VBE - LSM).The main idea of the method is to change computational model by applying the FMM to conventional VBE - LSM. The memory and operations could be reduced to be of linear proportion to the degree of freedom (DOF) and large scale problems could be effectively solved on a common desktop with this method. Numerical results show that this method holds virtues of high feasibility, accuracy and efficiency. Moreover, the idea of this method can be generalized and extended in application.


Author(s):  
Kuo Liu ◽  
Haibo Liu ◽  
Te Li ◽  
Yongqing Wang ◽  
Mingjia Sun ◽  
...  

The conception of the comprehensive thermal error of servo axes is given. Thermal characteristics of a preloaded ball screw on a gantry milling machine is investigated, and the error and temperature data are obtained. The comprehensive thermal error is divided into two parts: thermal expansion error ((TEE) in the stroke range) and thermal drift error ((TDE) of origin). The thermal mechanism and thermal error variation of preloaded ball screw are expounded. Based on the generation, conduction, and convection theory of heat, the thermal field models of screw caused by friction of screw-nut pairs and bearing blocks are derived. The prediction for TEE is presented based on thermal fields of multiheat sources. Besides, the factors influencing TDE are analyzed, and the model of TDE is established based on the least square method. The predicted thermal field of the screw is analyzed. The simulation and experimental results indicate that high accuracy stability can be obtained using the proposed model. Moreover, high accuracy stability can still be achieved even if the moving state of servo axis changes randomly, the screw is preloaded, and the thermal deformation process is complex. Strong robustness of the model is verified.


2008 ◽  
Author(s):  
Ruan Jiuhong ◽  
Yang Fuguang ◽  
Qiu Xuyun ◽  
Li Yibin

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