The Experts below are selected from a list of 165 Experts worldwide ranked by ideXlab platform

J. Otsuka - One of the best experts on this subject based on the ideXlab platform.

  • Nanometer level positioning using three kinds of Lead Screws
    Nanotechnology, 1992
    Co-Authors: J. Otsuka
    Abstract:

    A one-dimensional table unit with a laser feedback control system is manufactured, aiming at ultraprecision positioning of nanometer level accuracy by step response, with the use of one of the three kinds of Lead Screws (a precision sliding screw, a precision ball screw, and a rolled ball screw). The following items are made clear. (i) A quantified error (offset error) is caused by the proportional gain and D/A converter. (ii) In an effort to overcome this obstacle, the author devises a 'bit control'. This control method proves to be very effective in dealing with the quantified errors for three kinds of Lead Screws allowing one to obtain nanometer accuracy for all three. (iii) The characteristics of these three kinds of Lead Screws in the very short stroke range (0.1 mu m) are clarified. The precision sliding screw has a stick-slip between the screw and nut. The precision ball screw behaves elastically between them. The rolled ball screw shows a nanometer level positioning in spite of its large variation in friction torque and it having lowest accuracy.

Hong-sen Yan - One of the best experts on this subject based on the ideXlab platform.

  • Geometry design of trapezoidal threaded variable pitch Lead Screws
    Computers & Mathematics With Applications, 2002
    Co-Authors: Jen-yu Liu, Hong-sen Yan
    Abstract:

    Abstract Our purpose is to derive equations for variable pitch helix and helicoids, based on screw matrix transformations. Also mathematical models for the surface geometry of single, double, and Archimedean double trapezoidal threaded variable pitch Lead Screws are presented. Ther result of this work is important in the computer-aided design and manufacturing of trapezoidal threaded variable pitch Lead Screws for industrial applications.

  • Geometric Design and Machining of Variable Pitch Lead Screws with Swinging and Translating Meshing Rollers
    Jsme International Journal Series C-mechanical Systems Machine Elements and Manufacturing, 1997
    Co-Authors: Hong-sen Yan, Hong Yih Cheng
    Abstract:

    The design of variable pitch Lead Screws with swinging and translating meshing rollers is proposed in this study. Mathematical expressions representing the surface geometry of the screw generated by an endmill cutter are derived for the purpose of calculating the meshing points on the threaded surface of the screw. This mechanism is modeled using a Silicon Graphics workstation for motion simulation. Two examples are given. Our results show that constant thickness of screw threads can be attained using the design proposed. Finally, the machining settings of a 5-axis CNC machine are provided for manufacture of the Screws.

  • CURVATURE ANALYSIS OF VARIABLE PITCH Lead Screws WITH CYLINDRICAL MESHING ELEMENTS
    Transactions of The Canadian Society for Mechanical Engineering, 1996
    Co-Authors: Yaw Hong Kang, Hong-sen Yan
    Abstract:

    Based on coordinate transformation matrices and theory of gearing, we derive the mathematical expressions of surface geometry and the location of contact point of variable pitch Lead Screws. Accord...

  • Geometric Design and Machining of Variable Pitch Lead Screws with Cylindrical Meshing Elements
    Journal of Mechanical Design, 1993
    Co-Authors: Hong-sen Yan, Jen-yu Liu
    Abstract:

    This paper derives the surface geometry and machine tool settings for a double threaded variable pitch Lead screw with four cylindrical meshing elements. A 4-axis machining center with a rotary milling head attachment is adopted for the manufacturing of the profiles of the Screws. And, based on the developed surface equations and the required settings, the authors develop a computer program for solid modeling to simulate the surface geometry of such a mechanism before and after machining. The result of this work is necessary for the task of computer-aided design and manufacturing of the variable pitch Lead screw transmission mechanisms for industrial applications, e.g., in shuttleless weaving looms.

Hao Guangbo - One of the best experts on this subject based on the ideXlab platform.

  • Accuracy modeling and analysis for a lock-or-release mechanism of the Chinese Space Station Microgravity Platform
    'Elsevier BV', 2018
    Co-Authors: Ding Jian, Liu Jinguo, Zhang Rongpeng, Lu Zhang, Hao Guangbo
    Abstract:

    With development of Chinese space science and technology, plenty of microgravity experiments will be conducted in the Chinese Space Station to be built, and therefore demand for high-precision electromechanical equipment increases substantially. In this paper, a comprehensive accuracy analysis of a new type of auto lock-or-release (L/R) mechanism, which is applied in the Space Station Microgravity Platform (SSMP), is implemented. Firstly, two models (vector analysis model and vector differential model) are, therefore, proposed to analyze output errors of the mechanism. Due to transmission errors from the transmission chain of the gear mechanism, influence factors on axial errors of Lead Screws are analyzed using design of experiment (DOE) for factor sensitivities. It shows that manufacturing tolerances of the Lead screw is the dominant factor. Then, verification of the two proposed accuracy models is comparatively implemented through Monte Carlo (MC) simulation and DOE. Using the present accuracy model, location errors of the Lead screw throughout the mechanism's working stroke are illustrated, where the non-synchronous error of the mechanism is particularly discussed. A linear relation between the variance of the non-synchronous error and that of the structural error is established, followed by analyzing influence factors on the non-synchronous error. (C) 2018 Elsevier Ltd. All rights reserved

  • Accuracy modeling and analysis for a lock-or-release mechanism of the Chinese Space Station Microgravity Platform
    'Elsevier BV', 2018
    Co-Authors: Ding Jian, Liu Jinguo, Zhang Rongpeng, Lu Zhang, Hao Guangbo
    Abstract:

    With development of Chinese space science and technology, plenty of microgravity experiments will be conducted in the Chinese Space Station to be built, and therefore demand for high-precision electromechanical equipment increases substantially. In this paper, a comprehensive accuracy analysis of a new type of auto lock-or-release (L/R) mechanism, which is applied in the Space Station Microgravity Platform (SSMP), is implemented. Firstly, two models (vector analysis model and vector differential model) are, therefore, proposed to analyze output errors of the mechanism. Due to transmission errors from the transmission chain of the gear mechanism, influence factors on axial errors of Lead Screws are analyzed using design of experiment (DOE) for factor sensitivities. It shows that manufacturing tolerances of the Lead screw is the dominant factor. Then, verification of the two proposed accuracy models is comparatively implemented through Monte Carlo (MC) simulation and DOE. Using the present accuracy model, location errors of the Lead screw throughout the mechanism's working stroke are illustrated, where the non-synchronous error of the mechanism is particularly discussed. A linear relation between the variance of the non-synchronous error and that of the structural error is established, followed by analyzing influence factors on the non-synchronous error

Thierry A. Blanchet - One of the best experts on this subject based on the ideXlab platform.

  • Continuous-Thread Model of Load Distribution and Nut Wear in Grease-Lubricated Lead Screws
    Tribology Transactions, 2007
    Co-Authors: Thierry A. Blanchet
    Abstract:

    Even under constant operating conditions, greases lubricating Lead screw assemblies, as well as materials comprising their nut and screw threads, must perform over a range of contact pressures that not only varies from thread to thread but also evolves with the sliding distance as most heavily loaded threads wear most rapidly. An example modeled here, consisting of a nut whose bulk body is rigid and an elastic screw body having continuous elastic meshed threads, reveals the broad distribution of load along the length of the nut threads in an unworn Lead screw assembly, as well as the distribution of wear depth that must accompany an eventual steady-state of uniform rate of nut thread wear. Thread load redistributions brought on by changes in operating conditions such as applied load, or even temperature in the case of a nut/screw pair of dissimilar materials, are similarly modeled. Such load redistributions in worn Lead Screws may cause either the top or the bottom positions of the nut thread to become mo...

  • coupled evolution of load distribution and wear on grease lubricated Lead screw threads
    Tribology Transactions, 2006
    Co-Authors: Thierry A. Blanchet
    Abstract:

    Even under constant operating conditions, greases lubricating Lead screw assemblies, as well as materials comprising their nut and screw threads, must perform over a range of contact pressures that not only varies from thread-to-thread, but also evolves with the sliding distance as the most-heavily loaded threads wear most rapidly. An example modeled here, consisting of a rigid nut and elastic screw body having flexible meshed thread pairs, describes a broad distribution of loads thread-to-thread on a new Lead screw assembly that gradually evolves towards uniformity as the coupled consideration of thread loading and wear depth approaches a steady-state of equal rates of thread wear. Thread load redistributions brought on by changes in the operating conditions such as applied load, or even temperature in the case of a nut/screw pair of dissimilar materials, are similarly modeled. Such load redistributions in pre-worn Lead Screws may cause either the top or the bottom nut threads to become most heavily load...

  • Continuous-Thread Model of Load Distribution and Nut Wear in Grease-Lubricated Lead Screws
    Part A: Tribomaterials; Lubricants and Additives; Elastohydrodynamic Lubrication; Hydrodynamic Lubrication and Fluid Film Bearings; Rolling Element Be, 2006
    Co-Authors: Thierry A. Blanchet
    Abstract:

    Even under constant operating conditions, greases lubricating Lead screw assemblies, as well as materials comprising their nut and screw threads, must perform over a range of contact pressures that not only varies from thread-to-thread, but also evolves with sliding distance as most-heavily loaded threads wear most rapidly. An example modeled here, consisting of a nut whose bulk body is rigid and elastic screw body having continuous elastic meshed threads, reveals the broad distribution of load along the length of the nut threads in an unworn Lead screw assembly, as well as the distribution of wear depth that must accompany an eventual steady-state of uniform rate of nut thread wear. Thread load redistributions brought on by changes in operating conditions such as applied load, or even temperature in the case of a nut/screw pair of dissimilar materials, are similarly modeled. Such load redistributions in worn Lead Screws may cause either the top or the bottom positions of the nut thread to become most heavily loaded, depending on whether an operating condition is increased or decreased, and the extents of these redistributions using this continuous thread model can significantly exceed those predicted by a preliminary model where threads were considered as discrete turns. Operating condition changes are shown capable of causing worn threads at either extreme of the nut to become momentarily unloaded and removed from contact, and this continuous-thread model indicates that even smaller changes in operating condition can initiate such unloading, as compared to predictions from the discrete-thread model.Copyright © 2006 by ASME

  • Coupled Evolution of Load Distribution and Wear on Lead Screw Threads
    World Tribology Congress III Volume 2, 2005
    Co-Authors: Thierry A. Blanchet
    Abstract:

    To prescribe simulative contact pressures in benchtop wear tests on materials and lubricants for threads of Lead Screws, it is necessary to understand how applied load is distributed over those threads. While in threaded fasteners it is known that the first engaged nut thread carries the greatest load and experiences the highest contact pressure, in a Lead screw application with considerable sliding this most heavily nut thread will correspondingly wear most rapidly. This suggests instead an eventually uniform steady-state load distribution over the nut threads that should be considered in arriving at a lower contact pressure for simulative wear testing. A model is therefore developed for this coupled evolution of thread load distribution and wear.Copyright © 2005 by ASME

Kenneth Renny Simba - One of the best experts on this subject based on the ideXlab platform.

  • contouring control for three axis machine tools based on nonlinear friction compensation for Lead Screws
    International Journal of Machine Tools & Manufacture, 2016
    Co-Authors: Ba Dinh Bui, Naoki Uchiyama, Kenneth Renny Simba
    Abstract:

    Abstract Friction is the main disturbance in mechanical systems especially in computerized numerical control machine tools with high precision, speed, and performance requirements. Much recent research have proven that a controller with friction compensation provides better performance. Some classical friction models such as the Coulomb–viscous–Stribeck friction model, the Lugre model, and the Generalized Maxwell Slip (GMS) model have been proposed to compensate for frictional effects to reduce the contour error and to improve the surface quality. However, most of the conventional friction models focus on frictional properties in pre-sliding regime and low velocity sliding regime. These models do not fully describe and compensate for friction in machine tool systems in case of high speed motion or insufficient lubrication. This paper presents a new friction model that combines the conventional Coulomb-viscous friction model and a nonlinear sinusoidal component for fully describing the friction behaviour of feed drive systems. In addition, this study presents controller design with feed forward compensation based on the proposed friction model. Experiments were conducted to compare the control performance between the proposed and the conventional friction models. Experimental results indicate that the mean contour error has been significantly reduced by 26% after applying the proposed controller.