scholarly journals Parameter Identification of a Friction Model in Metal Cutting Simulations with GPU-Accelerated Meshfree Methods

Author(s):  
M. Afrasiabi ◽  
H. Klippel ◽  
M. Roethlin ◽  
K. Wegener
Author(s):  
Roger C. von Doenhoff ◽  
Robert J. Streifel ◽  
Robert J. Marks

Abstract A model of the friction characteristics of carbon brakes is proposed to aid in the understanding of the causes of brake vibration. The model parameters are determined by a genetic algorithm in an attempt to identify differences in friction properties between brake applications during which vibration occurs and those during which there is no vibration. The model computes the brake torque as a function of wheelspeed, brake pressure, and the carbon surface temperature. The surface temperature is computed using a five node temperature model. The genetic algorithm chooses the model parameters to minimize the error between the model output and the torque measured during a dynamometer test. The basics of genetic algorithms and results of the model parameter identification process are presented.


2020 ◽  
Vol 176 ◽  
pp. 105571 ◽  
Author(s):  
M. Afrasiabi ◽  
L. Meier ◽  
M. Röthlin ◽  
H. Klippel ◽  
K. Wegener

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 284 ◽  
Author(s):  
Bing Li ◽  
Yongde Zhang ◽  
Lipeng Yuan ◽  
Xiaolin Xi

Prostate cancer has one of the highest incidences of male malignant tumors worldwide. Its treatment involves the robotic implantation of radioactive seeds in the perineum, a safe and effective procedure for early, low-risk prostate cancer. In order to ensure precise positioning, the seed implantation needle is set at low terminal velocity. In this paper, the motion output position instability caused by the friction torque of the robot’s motor and rotating joint during low velocity motion was analyzed and studied. This paper also presents a compensation control method based on the LuGre friction model, which offers piecewise parameter identification with GA-PSO. First, based on an analysis of its structure and working principle, the friction torque model of the robotic system and the torque model of the driving motor are established, and the influence of friction torque on motion stability analyzed. Then, based on experimental data of the relationship between velocity and friction torque for no-friction compensation, the velocity point of the minimum torque of the rotating joint and the critical Stribeck velocity point were used for segmental parameter identification; cubic spline interpolation was used for segmental fitting. Furthermore, on the basis of the LuGre model identification method, parameter identification of the genetic algorithm-particle swarm optimization, and compensation control of the LuGre friction model, a control method is analysed and set forth. Malab2017a/Simulink simulation software was used to simulate and analyze the control method, and verify its feasibility. Finally, the cantilever prostate seed implantation robot system was tested to verify the effectiveness of the segmented identification method and the compensation control strategy. The results reveal that motion output position stability at low velocity meets the requirements of the cantilever prostate seed implantation robot, thus providing a vital reference for further research.


Author(s):  
LL Liu ◽  
ZY Wu

This paper presents a new parameter identification method of the Stribeck friction model based on limit cycles. A single degree of freedom mass spring system driven by a belt is studied, and the Stribeck friction model is established between the mass and belt. Limit cycle oscillation will occur when the system is unstable. The limit cycle curve is described by some main shape characteristic parameters using the modified Freeman chain code method. Thus, the Stribeck friction parameters can be identified by using the ergodic search method to minimize the Euclidean distance of the theoretical and identified limit cycle shape characteristic parameters. The parameter identification method based on limit cycles is different from the traditional identification methods. It only needs the displacement and velocity responses of the system instead of the measurement of the friction force or motor voltage/current. All of these works can provide the reference for the research work of the friction parameter identification.


2011 ◽  
Vol 117-119 ◽  
pp. 1788-1791
Author(s):  
Yue Feng Yuan ◽  
Wu Yi Chen

It is necessary for cutting simulation to determine the friction model at the tool-chip interface suitable for metal cutting process. Cutting force experiments in orthogonal turning titanium alloy TI6AL4V are carried out with cement carbide tool KW10. The Coulomb frictions at the tool-chip interface are calculated based on measured cutting force, and the friction model is regressed, where cutting speed and feed rate are presented.


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