scholarly journals Estimation And Compensation of Angular Misalignment At Robot End Brush Roller - Workpiece Contact Interface Via Elastic Contact Force Perception

2021 ◽  
Author(s):  
Xiaozhi Feng ◽  
Rui Lv ◽  
Chen Qian ◽  
Yudi Wang ◽  
Linli Tian ◽  
...  
Keyword(s):  
Contact Force ◽  
Error Compensation ◽  
Large Scale ◽  
Machining Process ◽  
Elastic Contact ◽  
Contact Interface ◽  
Angular Misalignment ◽  
Force Perception ◽  
Robotic Grinding ◽  
Control Command

Abstract When the non-standard customized brush roller tool is used for robotic grinding of large-scale components, the clamping and positioning error of the brush roller at the end of the robot is extremely easy to cause misalignment at the brush roller - workpiece contact interface, which will affect the machining accuracy and surface quality. In order to ensure the parallel contact between the brush roller and the workpiece surface during the machining process, a calculation model of the angular misalignment at the brush roller - workpiece contact interface is proposed based on the elastic contact force perception, and then the accurate positioning of the robot end brush roller is realized by a fast compensation method. Firstly, according to the geometric force relationship between the brush roller and the workpiece, as well as the determined brush roller material properties parameters, the estimation model of angular misalignment is established. Secondly, both the axial force and normal torque at the time of initial contact detected by the force-controlled sensor are regarded as the input parameters in the model. Further, the calculated brush roller - workpiece contact offset is used as the geometric error compensation amount, and the brush roller is deflected to achieve error compensation by the robot RAPID program control command. The finite element simulation results are compared with the theoretical calculation values, and the average relative error is 15.1%. The experiment on robotic grinding and brushing of high-speed rail body indicates that the compensated angle can be reduced to 0.024° from an average of 0.179° before compensation, coupled with uniform material removal depth. The proposed method can significantly improve the contour accuracy of large-scale components.

BRUSHFORM 65

Alloy Digest ◽  
2013 ◽  
Vol 62 (6) ◽  
Keyword(s):  
Physical Properties ◽  
Tensile Properties ◽  
Contact Force ◽  
Temperature Rise ◽  
Power Loss ◽  
High Reliability ◽  
Superior Performance ◽  
Contact Interface ◽  
Resistive Heating ◽  
Computer Power

Abstract BrushForm 65 is designed for both superior performance and high reliability in appliance, automotive, and computer power applications. Alloy BF-65’s combination of properties limits power loss at the contact interface, controls temperature rise from resistive heating, and provides stable contact force at temperatures to 200 C (390 F). This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fatigue. It also includes information on forming. Filing Code: Cu-821. Producer or source: Materion Brush Performance Alloys.

Research on Thermally Induced Deformation of Reinforcing Plate Based on Finite Element Simulation

2012 ◽  
Vol 197 ◽  
pp. 139-143
Author(s):  
Hua Bai ◽  
Yi Du Zhang
Keyword(s):  
Finite Element ◽  
Ambient Temperature ◽  
Finite Element Simulation ◽  
Temperature Change ◽  
Large Scale ◽  
Machining Process ◽  
Reinforcement Structure ◽  
Thermally Induced ◽  
Finite Element Software ◽  
Element Simulation

The change of ambient temperature will cause deformation during the machining process of large-scale aerospace monolithic component. Based on finite element simulation, thermally induced deformation of reinforcing plate is studied in such aspects as reinforcement structure, clamping method and temperature change, and contact function in finite element software is used to simulate the unilateral constraint between workpiece and worktable. The results indicate that reinforcing plate will produce warping deformation due to the change of ambient temperature. Different reinforcement structures and clamping methods have important influence on the deformation positions and degrees, and the deformation is proportional to the temperature change.

Nucleation Processes in Large Scale Vapor Explosions

1979 ◽  
Vol 101 (2) ◽  
pp. 280-287 ◽  
Author(s):  
R. E. Henry ◽  
H. K. Fauske
Keyword(s):  
Large Scale ◽  
Interface Temperature ◽  
Liquid Droplets ◽  
Contact Interface ◽  
Vapor Cavity ◽  
Spontaneous Nucleation ◽  
System Pressure ◽  
Nucleation Model ◽  
Vapor Explosions ◽  
Cold Liquid

A spontaneous nucleation model is proposed for the mechanisms which lead to explosive boiling in the free contacting mode. The model considers that spontaneous nucleation cannot occur until the thermal boundary layer is sufficiently thick to support a critical size vapor cavity, and that significant bubble growth requires an established pressure gradient in the cold liquid. This results in a prediction that, for an interface temperature above the spontaneous nucleation limit, large cold liquid droplets will remain in film boiling due to coalescence of vapor nuclei, whereas smaller droplets will be captured by the hot liquid surface and rapidly vaporize, which agrees with the experimental observations. The model also predicts that explosions are eliminated by an elevated system pressure or a supercritical contact interface temperature, and this is also in agreement with experimental data.

Mobile Agent-Based Computing Resource and Usage Monitoring at Large Scale Computer Centers

2011 ◽  
Author(s):  
Zhixin Tie ◽  
David Ko ◽  
Harry H. Cheng
Keyword(s):  
Monitoring System ◽  
Mobile Agent ◽  
Computer Games ◽  
Data Exchange ◽  
Large Scale ◽  
Agent Based ◽  
Computer Center ◽  
Control Command ◽  
Computer Centers ◽  
Computer Resources

Mobile agent technology has become an important approach for the design and development of distributed systems. However, there is little research regarding the monitoring of computer resources and usage at large scale distributed computer centers. This paper presents a mobile agent-based system called the Mobile Agent Based Computer Monitoring System (MABCMS) that supports the dynamic sending and executing of control command, dynamic data exchange, and dynamic deployment of mobile code in C/C++. Based on the Mobile-C library, agents can call low level functions in binary dynamic or static libraries, and thus can monitor computer resources and usage conveniently and efficiently. Two experimental applications have been designed using the MABCMS. The experiments were conducted in a university computer center with hundreds of computer workstations and 15 server machines. The first experiment uses the MABCMS to detect improper usage of the computer workstations, such as playing computer games. The second experimental application uses the MABCMS to detect system resources such as available hard disk space. The experiments show that the mobile agent based monitoring system is an effective method for detecting and interacting with students playing computer games and a practical way to monitor computer resources in large scale distributed computer centers.

A simple and rapid calibration methodology for industrial robot based on geometric constraint and two-step error

2018 ◽  
Vol 45 (6) ◽  
pp. 715-721 ◽  
Author(s):  
Jiabo Zhang ◽  
Xibin Wang ◽  
Ke Wen ◽  
Yinghao Zhou ◽  
Yi Yue ◽  
...  
Keyword(s):  
Coordinate System ◽  
Large Scale ◽  
Industrial Robot ◽  
Geometric Constraint ◽  
Machining Process ◽  
Kinematic Parameters ◽  
Robot Calibration ◽  
Positioning Accuracy ◽  
Content Type ◽  
Rapid Calibration

Purpose The purpose of this study is the presentation and research of a simple and rapid calibration methodology for industrial robot. Extensive research efforts were devoted to meet the requirements of online compensation, closed-loop feedback control and high-precision machining during the flexible machining process of robot for large-scale cabin. Design/methodology/approach A simple and rapid method to design and construct the transformation relation between the base coordinate system of robot and the measurement coordinate system was proposed based on geometric constraint. By establishing the Denavit–Hartenberg model for robot calibration, a method of two-step error for kinematic parameters calibration was put forward, which aided in achievement of step-by-step calibration of angle and distance errors. Furthermore, KUKA robot was considered as the research object, and related experiments were performed based on laser tracker. Findings The experimental results demonstrated that the accuracy of the coordinate transformation could reach 0.128 mm, which meets the transformation requirements. Compared to other methods used in this study, the calibration method of two-step error could significantly improve the positioning accuracy of robot up to 0.271 mm. Originality/value The methodology based on geometric constraint and two-step error is simple and can rapidly calibrate the kinematic parameters of robot. It also leads to the improvement in the positioning accuracy of robot.

Micro texturing on metallic surfaces: State of the art

2016 ◽  
Vol 232 (6) ◽  
pp. 941-964 ◽  
Author(s):  
Divyansh Patel ◽  
VK Jain ◽  
J Ramkumar
Keyword(s):  
Large Scale ◽  
Surface Texturing ◽  
Machining Process ◽  
Electrochemical Micromachining ◽  
Metallic Surface ◽  
Textured Surface ◽  
Textured Surfaces ◽  
Metallic Surfaces ◽  
Area Of Interest ◽  
Micro Channels

The study of surface texturing on a metallic surface has become a great area of interest of researchers in the last few decades. Surface texturing is employed for enhancing the performance of the surface in its working environment. As the characterization techniques have been evolving very fast, researchers have started mimicking the natural surfaces to take the advantages of their characteristics (such as self-cleaning, load capacity, reducing coefficient of friction). Manufacturing of natural inspired surface requires having a great control over the process to achieve the micro or nano features on the natural surfaces. Hence, the selection of the most suitable process and optimum parameters for machining of arrays of micro or nano features at large scale is highly desirable. This study reports an overview of different micromachining processes used for texturing on metallic surfaces and research gaps to be filled in the available literature. Electrochemical micromachining has tremendous potential on account of its versatility in different applications. It is a promising and economically viable machining process for micromanufacturing industries for fabrication of micro textures and micro features on metallic surfaces. Production of textured surface at large scale requires a sustainable technology, which can serve the purpose of enhancing the performance of the surface without changing the original properties of the surface. Indeed, laser surface texturing, through-mask electrochemical micromachining, lithography, micro- or nanocasting and so on are the existing methods which involve multiple steps for generation of textured surfaces. This article also reports some original experimental investigations for generation of different kinds of micro textures on metallic surfaces, namely, arrays of micro dimples, micro channels and micro pillars using a single-step maskless electrochemical micro-texturing process with a pre-patterned micro tool.

Positioning Error Compensation for Machining Center Based on Spline Interpolation

2012 ◽  
Vol 472-475 ◽  
pp. 3029-3034
Author(s):  
Peng Li ◽  
Ying Hu ◽  
Zi Ma
Keyword(s):  
Error Compensation ◽  
Laser Interferometer ◽  
Spline Interpolation ◽  
Machining Process ◽  
Accuracy Evaluation ◽  
Positioning Error ◽  
Positioning Errors ◽  
Machining Center ◽  
Compensation Function ◽  
Manual Correction

Related to the machining precision, especially for the middle and low end machining center, the positioning error is often considered as a major factor, which can be traditionally decreased by the pitch compensation function integrated in the CNC system. However, the function is just founded on that all of positioning errors remain constant in the machining process, and it is difficulty to meet the compensation needs in different machining condition. At the same time, it involves a mass of parameters that need professional manual correction. Therefore, the software error compensation method is put forward. Firstly, based on cubic spline interpolation, the error compensation model is designed through the processing of positioning error which is collected by the laser interferometer. Secondly, with the characteristics of G codes, the database is established for error compensation, which can effectively correct different machining G codes with enough error information. Finally, by the experiment and accuracy evaluation, results show that after the positioning error of machining center is compensated by the presented scheme, its precision is improved obviously.

Explicit Finite Element Models of Friction Dampers in Forced Response Analysis of Bladed Discs

2007 ◽  
Author(s):  
E. P. Petrov
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Dynamic Properties ◽  
Forced Response ◽  
Response Analysis ◽  
Contact Interactions ◽  
Contact Interface ◽  
Explicit Finite Element ◽  
Friction Dampers ◽  
Time Dynamic

A generic method for analysis of nonlinear forced response for bladed discs with friction dampers of different design has been developed. The method uses explicit finite element modelling of dampers, which allows accurate description of flexibility and, for the first time, dynamic properties of dampers of different design in multiharmonic analysis of bladed discs. Large-scale finite element damper and bladed disc models containing 104–106 DOFs can be used. These models, together with detailed description of contact interactions over contact interface areas, allow for any level of refinement required for modelling of elastic damper bodies and for modelling of friction contact interactions. Numerical studies of realistic bladed discs have been performed with three different types of underplatform dampers: (i) a ‘cottage-roof’ (called also ‘wedge’) damper; (ii) seal wire damper; and (iii) a strip damper. Effects of contact interface parameters and excitation levels on damping properties of the dampers and forced response are extensively explored.

Generalized definition and application of tolerance

2019 ◽  
Vol 233 (19-20) ◽  
pp. 6807-6814
Author(s):  
Hao Jianjun ◽  
Wang Youli ◽  
Wang Xiaohui
Keyword(s):  
Error Compensation ◽  
Extreme Values ◽  
Probabilistic Method ◽  
Tolerance Analysis ◽  
Machining Process ◽  
Negative Number ◽  
Absolute Value ◽  
Calculation Results ◽  
Relationship Of ◽  
Dimensional Homogeneity

Tolerance with upper deviation less than lower deviation is defined as virtual tolerance; the dimension between two extreme values required with tolerance (virtual tolerance) is expressed by a set. The changed characteristics of the set range when the tolerance value is continuously reduced from positive to negative are explored. The nature of virtual tolerance is that the absolute value of virtual tolerance is the error compensation amount, and the dimension between two extreme values is the error compensation range. On the basis of the concept of positive and negative number, the theory of dimensional homogeneity, the existing conditions of the general formula of the dimensional chain, the accuracy of the calculation results of tolerance, and so on, the concept of virtual tolerance and its relationship of unity of opposites with tolerance are proposed. Based on the concept of virtual tolerance, analysis and calculation processes of various assembly dimensional chains are unified, and general formulation of calculating the range of false waste is established, and the method of determining the range of false waste by using probabilistic method in machining process is deduced.

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